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• 2231. [Article] All in a DNA's work : conservation genetics and monitoring of the New Zealand endemic Maui's and Hector's dolphins

  The critically endangered Maui's dolphin (Cephalorhynchus hectori maui) and the endangered Hector's dolphin (C. h. hectori) are endemic to the coastal waters of New Zealand, where their primary threat ...

  Citation × Citation Citation Abstract Copy Title: All in a DNA's work : conservation genetics and monitoring of the New Zealand endemic Maui's and Hector's dolphins Author: Hamner, Rebecca Marie The critically endangered Maui's dolphin (Cephalorhynchus hectori maui) and the endangered Hector's dolphin (C. h. hectori) are endemic to the coastal waters of New Zealand, where their primary threat is fisheries-related mortality. The Maui's dolphin is among the most critically endangered cetaceans in the world, with its remnant population primarily concentrated in approximately 140 km along the central west coast of New Zealand's North Island. Its closely related sister subspecies, the Hector's dolphin, is more abundant and offers a useful comparison for studying the Maui's dolphin. My work used genetic tools to examine demographic and genetic parameters relevant for conservation considerations regarding Maui's and Hector's dolphins, as well as to build upon past genetic baselines for the purpose of long-term genetic monitoring of these subspecies. Three genetic datasets formed the basis for most analyses: (1) Maui's 01-07, including 54 Maui's dolphin individuals sampled between 2001 and 2007 (n = 70 biopsies, 12 beachcast); (2) Maui's 10-11, including 40 Maui's dolphin individuals sampled in 2010 and 2011 (n = 69 biopsies, 1 beachcast); and (3) Hector's CB11-12, including 148 Hector's dolphin individuals sampled in Cloudy Bay in 2011 and 2012 (n = 263 biopsies). Microsatellite genotypes were used to identify individuals for a genotype recapture abundance estimate of individuals age 1⁺ (N₁₊) and for the estimation of effective population size (N[subscript e]). Both populations exhibited a high N[subscript e] relative to N₁₊, consistent with expectations given their life history characteristics and the limited data available for other dolphin species. The abundance of Maui's dolphins was confirmed to be very low, Maui's 10-11 N₁₊ = 55 (95% CL = 48 - 69), and as expected, it had much lower linkage disequilibrium N[subscript e] (61, 95% CL = 29 - 338) than Hector's CB11-12 (N[subscript e] = 207, 95% CL = 127 - 447; N₁₊ = 272, 95% CL = 236 - 323). The slightly higher Ne/N₁₊ ratio of the Maui's dolphin compared to the Hector's dolphin is consistent with a recent decline in the Maui's dolphin. Although the point estimates of both N[subscript e] and N₁₊ decreased between the two Maui's dolphin datasets (Maui's 01-07: N[subscript e] = 74, 95% CL = 37 - 318; N₁₊ = 69, 95% CL = 38 - 125), the confidence intervals widely overlapped. Maui's 10-11 had significantly fewer alleles (average 4 alleles/locus) and lower heterozygosity (H₀ = 0.316, H[subscript e] = 0.319) than Hector's CB11-12 (average 7 alleles/locus, H₀ = 0.500, H[subscript e] = 0.495; all P <0.001). Interestingly, one microsatellite locus (PPHO104) had anomalously high diversity (31 to 63 alleles) in both Hector's and Maui's dolphins and appears to be influenced by diversifying selection. The observed and expected heterozygosity, internal relatedness, and F[subscript IS] of Maui's dolphins all showed patterns consistent with a decline of the subspecies, although none differed significantly over the short time interval between the two datasets collected in 2001-07 and 2010-11. The lack of significant decline in any of the parameters analyzed for Maui's dolphins is not surprising given the low power to detect a low to moderate decline over the short interval (<1 generation) between the two sampling periods. Compared to minimum viable effective population sizes proposed to guide management decisions, the Maui's dolphin has declined below the recommended threshold of N[subscript e] = 50, recently increased to N[subscript e] ≥100, thought to be necessary to avoid inbreeding depression in the short term (5 generations, ~65.2 years for Maui's and Hector's dolphins). Additionally, both the Maui's dolphin and Cloudy Bay Hector's dolphin populations are below the recommended threshold of N[subscript e] = 500, recently increased to N[subscript e] ≥1000, thought to be necessary to preserve long-term evolutionary potential. This is less of a concern for the Cloudy Bay Hector's population, which is thought to maintain gene flow with neighboring populations. However, for the small, isolated Maui's dolphin population, inbreeding depression is likely to be an increasing concern. Furthermore, each Maui's dolphin individual holds a disproportionate amount of the total genetic variation of the subspecies and would represent a disproportionately large demographic and genetic loss if it died before realizing its reproductive potential in the population. There is, however, potential for genetic restoration by interbreeding with Hector's dolphins, as genetic monitoring of Maui's dolphins revealed the first contemporary dispersal of four (two living females, one dead female, one dead male) Hector's dolphins into the Maui's dolphin distribution. Two Hector's dolphins (one dead female neonate, one living male) were also sampled along the North Island's southwest coast, outside the presumed range of either subspecies. Together, these records provide evidence of long-distance dispersal by Hector's dolphins (≥400 km) and the possibility of an unsampled Hector's dolphin population along the southwest coast of the North Island or northern South Island. These results highlight the value of genetic monitoring for subspecies lacking distinctive physical appearances, as such discoveries are not detected by other means but have important conservation implications. Although the Maui's dolphin is critically endangered, it is not necessarily doomed to extinction. The subspecies appears to be maintaining an equal sex ratio and connectivity within its remnant range, and the highly diverse locus PPHO104 could potentially offer clues to an inbreeding avoidance mechanism. If Maui's dolphins interbreed with the recently identified Hector's dolphin immigrants, it could provide genetic restoration, enhancing chances of long-term survival of the Maui's dolphin. Continued genetic monitoring and examination of recovered carcasses for phenotypic signs of inbreeding are important for gauging genetic threats to the survival of Maui's dolphins, as well as determining if any Hector's dolphin populations appear to be declining toward the critically endangered state of the Maui's dolphin. The results of this work contributed to the decision by the New Zealand Department of Conservation and Ministry for Primary Industries to conduct an updated risk assessment for Maui's dolphins and accelerate the review of the Maui's Dolphin Threat Management Plan. Consequently, commercial and recreational set net restrictions were extended slightly to reduce entanglement risk to Maui's dolphins utilizing the southern part of their distribution, as well as any Hector's dolphins that disperse north into that area. The results related to the population of Hector's dolphins in Cloudy Bay provide information that will contribute to the upcoming review of the Hector's dolphin component of the Threat Management Plan. Title: All in a DNA's work : conservation genetics and monitoring of the New Zealand endemic Maui's and Hector's dolphins Author: Hamner, Rebecca Marie The critically endangered Maui's dolphin (Cephalorhynchus hectori maui) and the endangered Hector's dolphin (C. h. hectori) are endemic to the coastal waters of New Zealand, where their primary threat is fisheries-related mortality. The Maui's dolphin is among the most critically endangered cetaceans in the world, with its remnant population primarily concentrated in approximately 140 km along the central west coast of New Zealand's North Island. Its closely related sister subspecies, the Hector's dolphin, is more abundant and offers a useful comparison for studying the Maui's dolphin. My work used genetic tools to examine demographic and genetic parameters relevant for conservation considerations regarding Maui's and Hector's dolphins, as well as to build upon past genetic baselines for the purpose of long-term genetic monitoring of these subspecies. Three genetic datasets formed the basis for most analyses: (1) Maui's 01-07, including 54 Maui's dolphin individuals sampled between 2001 and 2007 (n = 70 biopsies, 12 beachcast); (2) Maui's 10-11, including 40 Maui's dolphin individuals sampled in 2010 and 2011 (n = 69 biopsies, 1 beachcast); and (3) Hector's CB11-12, including 148 Hector's dolphin individuals sampled in Cloudy Bay in 2011 and 2012 (n = 263 biopsies). Microsatellite genotypes were used to identify individuals for a genotype recapture abundance estimate of individuals age 1⁺ (N₁₊) and for the estimation of effective population size (N[subscript e]). Both populations exhibited a high N[subscript e] relative to N₁₊, consistent with expectations given their life history characteristics and the limited data available for other dolphin species. The abundance of Maui's dolphins was confirmed to be very low, Maui's 10-11 N₁₊ = 55 (95% CL = 48 - 69), and as expected, it had much lower linkage disequilibrium N[subscript e] (61, 95% CL = 29 - 338) than Hector's CB11-12 (N[subscript e] = 207, 95% CL = 127 - 447; N₁₊ = 272, 95% CL = 236 - 323). The slightly higher Ne/N₁₊ ratio of the Maui's dolphin compared to the Hector's dolphin is consistent with a recent decline in the Maui's dolphin. Although the point estimates of both N[subscript e] and N₁₊ decreased between the two Maui's dolphin datasets (Maui's 01-07: N[subscript e] = 74, 95% CL = 37 - 318; N₁₊ = 69, 95% CL = 38 - 125), the confidence intervals widely overlapped. Maui's 10-11 had significantly fewer alleles (average 4 alleles/locus) and lower heterozygosity (H₀ = 0.316, H[subscript e] = 0.319) than Hector's CB11-12 (average 7 alleles/locus, H₀ = 0.500, H[subscript e] = 0.495; all P <0.001). Interestingly, one microsatellite locus (PPHO104) had anomalously high diversity (31 to 63 alleles) in both Hector's and Maui's dolphins and appears to be influenced by diversifying selection. The observed and expected heterozygosity, internal relatedness, and F[subscript IS] of Maui's dolphins all showed patterns consistent with a decline of the subspecies, although none differed significantly over the short time interval between the two datasets collected in 2001-07 and 2010-11. The lack of significant decline in any of the parameters analyzed for Maui's dolphins is not surprising given the low power to detect a low to moderate decline over the short interval (<1 generation) between the two sampling periods. Compared to minimum viable effective population sizes proposed to guide management decisions, the Maui's dolphin has declined below the recommended threshold of N[subscript e] = 50, recently increased to N[subscript e] ≥100, thought to be necessary to avoid inbreeding depression in the short term (5 generations, ~65.2 years for Maui's and Hector's dolphins). Additionally, both the Maui's dolphin and Cloudy Bay Hector's dolphin populations are below the recommended threshold of N[subscript e] = 500, recently increased to N[subscript e] ≥1000, thought to be necessary to preserve long-term evolutionary potential. This is less of a concern for the Cloudy Bay Hector's population, which is thought to maintain gene flow with neighboring populations. However, for the small, isolated Maui's dolphin population, inbreeding depression is likely to be an increasing concern. Furthermore, each Maui's dolphin individual holds a disproportionate amount of the total genetic variation of the subspecies and would represent a disproportionately large demographic and genetic loss if it died before realizing its reproductive potential in the population. There is, however, potential for genetic restoration by interbreeding with Hector's dolphins, as genetic monitoring of Maui's dolphins revealed the first contemporary dispersal of four (two living females, one dead female, one dead male) Hector's dolphins into the Maui's dolphin distribution. Two Hector's dolphins (one dead female neonate, one living male) were also sampled along the North Island's southwest coast, outside the presumed range of either subspecies. Together, these records provide evidence of long-distance dispersal by Hector's dolphins (≥400 km) and the possibility of an unsampled Hector's dolphin population along the southwest coast of the North Island or northern South Island. These results highlight the value of genetic monitoring for subspecies lacking distinctive physical appearances, as such discoveries are not detected by other means but have important conservation implications. Although the Maui's dolphin is critically endangered, it is not necessarily doomed to extinction. The subspecies appears to be maintaining an equal sex ratio and connectivity within its remnant range, and the highly diverse locus PPHO104 could potentially offer clues to an inbreeding avoidance mechanism. If Maui's dolphins interbreed with the recently identified Hector's dolphin immigrants, it could provide genetic restoration, enhancing chances of long-term survival of the Maui's dolphin. Continued genetic monitoring and examination of recovered carcasses for phenotypic signs of inbreeding are important for gauging genetic threats to the survival of Maui's dolphins, as well as determining if any Hector's dolphin populations appear to be declining toward the critically endangered state of the Maui's dolphin. The results of this work contributed to the decision by the New Zealand Department of Conservation and Ministry for Primary Industries to conduct an updated risk assessment for Maui's dolphins and accelerate the review of the Maui's Dolphin Threat Management Plan. Consequently, commercial and recreational set net restrictions were extended slightly to reduce entanglement risk to Maui's dolphins utilizing the southern part of their distribution, as well as any Hector's dolphins that disperse north into that area. The results related to the population of Hector's dolphins in Cloudy Bay provide information that will contribute to the upcoming review of the Hector's dolphin component of the Threat Management Plan. Close

• 2232. [Article] Statistical Methods for Tissue Culture Medium Optimization and A Multiplexed Fingerprinting Set for Hazelnuts

  Hazelnut is one of the most important nuts in worldwide production and the European hazelnut (Corylus avellana L.) is the most economically important of the 11 recognized hazelnut species. Development ...

  Citation × Citation Citation Abstract Copy Title: Statistical Methods for Tissue Culture Medium Optimization and A Multiplexed Fingerprinting Set for Hazelnuts Author: Akin, Melekşen Hazelnut is one of the most important nuts in worldwide production and the European hazelnut (Corylus avellana L.) is the most economically important of the 11 recognized hazelnut species. Development of new cultivars is continuous, with emphasis on better nut quality, high yield and disease resistance. Hazelnuts are highly heterozygous, and clonally propagated. Traditional propagation methods in hazelnut are not rapid enough to provide the required nursery stock for newly released hazelnut cultivars, but micropropagation can provide rapid production of hazelnut planting stock. Several growth media are available for specific cultivars, but many are not suitable for the wide range of germplasm used in new cultivars. Micropropagation of hazelnuts remains challenging due to the various responses of diverse genotypes to in vitro growth. Several studies incrimentally improved the growth medium, but determining exact nutrient requirements was difficult. The aim of this study was to determine which statistical methods would make the growth medium optimization process more practical and to develop an optimal micropropagation medium for diverse hazelnuts by testing salts and ions as factors within the experimental design. In addition an SSR fingerprinting set suitable for a diverse group of hazelnuts was developed. The first study was designed to test the effect of salts on three hazelnut genotypes and compare two methods of data analysis. Driver and Kuniyuki Walnut medium (DKW) macro-salts (NH₄NO₃, Ca(NO₃)₂∙4H₂O, CaCl₂∙2H₂O, MgSO₄∙7H₂O, KH₂PO₄ and K₂SO₄) were varied from 0.5× to 3× DKW concentrations with 42 combinations in a IV-optimal design. Shoot quality, shoot length, multiplication and callus formation were rated and analyzed using Response Surface Methodology (RSM) and the Chi-Squared Automatic Interaction Detection (CHAID) data mining algorithm. Both analyses indicated that NH₄NO₃ was a predominant nutrient factor. RSM results were genotype dependent while CHAID included genotype as a factor in the analysis, allowing development of a common medium rather than several genotype-specific media. Overall, CHAID results were more specific and easier to interpret than RSM graphs. The optimal growth medium for diverse hazelnut genotypes was formulated as: 0.5× NH₄NO₃, 3× KH₂PO₄, 1.5× Ca(NO₃)₂ and and the rest of the macro salts set at 1× DKW with modified minor nutrients [4× H₃BO₃, 4× Na₂MoO₄∙2H₂O, 4× Zn(NO₃)₂∙6H₂O, 0.5× MnSO₄∙H₂O, 0.5× CuSO₄∙5H₂O]. The second study was to determine the effects of ions on tissue culture medium optimization. NH₄⁺, Ca²⁺, Mg²⁺, SO₄²⁻ and PO₄³⁻ ions were used as factors in a D-optimal design. K⁺ and NO₃⁻ ions were used to bring the pH level to neutral, and as factors in the statistical analysis. The CHAID data mining algorithm was used to analyze shoot growth responses of three hazelnut genotypes. The algorithm trees revealed significant variables and their interactions, and provided exact cut-off amounts for each of the ions for the related growth response by incorporating genotype as an independent factor. The critical cut-off values for good shoot quality, elongation, multiplication and medium callus formation were suggested to be: NO₃⁻ <88 mM, NH₄⁺ <20 mM, Ca²⁺ <5 mM, Mg²⁺ >5 mM and K⁺ <46 mM. Another step of the research was to develop a reliable and economical fingerprinting set consisting of high core-repeat SSRs (≥3) for genotype identification of 102 hazelnut accessions. Identification of trueness-to-type by phenotypic observation is very difficult and labeling mistakes during the several steps of micropropagation can result in costly errors. The use of SSRs for plant identification is preferred over other molecular markers because they are reproducible across laboratories, exhibit co-dominant inheritance, have a large number of alleles per locus and are randomly distributed throughout the genome. Twenty SSRs containing repeat motifs of three or more nucleotides distributed throughout the hazelnut genome were screened on eight genetically diverse cultivars to assess polymorphism, allele size range, and ease of scoring. Six SSRs were discarded after genotyping 96 hazelnut samples, either due to large allele bin widths and/or alleles that do not match the motifs, complicating allele scoring. Fourteen polymorphic, easy-to-score SSRs with non-overlapping alleles were selected and amplified in a single multiplex. The multiplexed set generated the same alleles that were obtained when amplifying each SSR individually in the eight test accessions. SSR primer concentrations were then optimized to generate a clear signal for each locus. This 14-SSR fingerprinting set was used to genotype 102 hazelnut accessions, and distinguished unique accessions mainly according to parentage and in some cases based on geographic origin. As a result of these studies, salt- and ion-based optimized tissue culture medium formulations were developed for diverse hazelnuts. The importance of salts and ions as factors within the experimental design and analysis was examined, and using salts as factors results in complexity within the design as the effects of ions can not be determined. Although salt optimization studies are still a powerful tool, and are experimentally easier, optimization at the ionic level provided a clearer evaluation of the ion-based growth responses, because the plants take up minerals as ions of the corresponding salts. Data mining (CHAID) was used to make the tissue culture optimization process more practical compared to analysis with the standard ANOVA, regression and RSM. CHAID delineated specific concentrations that were effective and allowed easier analysis of nutrient content for an improved medium. A reliable and cost-effective multiplexed fingerprinting set of 14 SSR markers was developed for confirming identity and paternity in diverse hazelnut cultivars and species and 102 accessions were fingerprinted. Title: Statistical Methods for Tissue Culture Medium Optimization and A Multiplexed Fingerprinting Set for Hazelnuts Author: Akin, Melekşen Hazelnut is one of the most important nuts in worldwide production and the European hazelnut (Corylus avellana L.) is the most economically important of the 11 recognized hazelnut species. Development of new cultivars is continuous, with emphasis on better nut quality, high yield and disease resistance. Hazelnuts are highly heterozygous, and clonally propagated. Traditional propagation methods in hazelnut are not rapid enough to provide the required nursery stock for newly released hazelnut cultivars, but micropropagation can provide rapid production of hazelnut planting stock. Several growth media are available for specific cultivars, but many are not suitable for the wide range of germplasm used in new cultivars. Micropropagation of hazelnuts remains challenging due to the various responses of diverse genotypes to in vitro growth. Several studies incrimentally improved the growth medium, but determining exact nutrient requirements was difficult. The aim of this study was to determine which statistical methods would make the growth medium optimization process more practical and to develop an optimal micropropagation medium for diverse hazelnuts by testing salts and ions as factors within the experimental design. In addition an SSR fingerprinting set suitable for a diverse group of hazelnuts was developed. The first study was designed to test the effect of salts on three hazelnut genotypes and compare two methods of data analysis. Driver and Kuniyuki Walnut medium (DKW) macro-salts (NH₄NO₃, Ca(NO₃)₂∙4H₂O, CaCl₂∙2H₂O, MgSO₄∙7H₂O, KH₂PO₄ and K₂SO₄) were varied from 0.5× to 3× DKW concentrations with 42 combinations in a IV-optimal design. Shoot quality, shoot length, multiplication and callus formation were rated and analyzed using Response Surface Methodology (RSM) and the Chi-Squared Automatic Interaction Detection (CHAID) data mining algorithm. Both analyses indicated that NH₄NO₃ was a predominant nutrient factor. RSM results were genotype dependent while CHAID included genotype as a factor in the analysis, allowing development of a common medium rather than several genotype-specific media. Overall, CHAID results were more specific and easier to interpret than RSM graphs. The optimal growth medium for diverse hazelnut genotypes was formulated as: 0.5× NH₄NO₃, 3× KH₂PO₄, 1.5× Ca(NO₃)₂ and and the rest of the macro salts set at 1× DKW with modified minor nutrients [4× H₃BO₃, 4× Na₂MoO₄∙2H₂O, 4× Zn(NO₃)₂∙6H₂O, 0.5× MnSO₄∙H₂O, 0.5× CuSO₄∙5H₂O]. The second study was to determine the effects of ions on tissue culture medium optimization. NH₄⁺, Ca²⁺, Mg²⁺, SO₄²⁻ and PO₄³⁻ ions were used as factors in a D-optimal design. K⁺ and NO₃⁻ ions were used to bring the pH level to neutral, and as factors in the statistical analysis. The CHAID data mining algorithm was used to analyze shoot growth responses of three hazelnut genotypes. The algorithm trees revealed significant variables and their interactions, and provided exact cut-off amounts for each of the ions for the related growth response by incorporating genotype as an independent factor. The critical cut-off values for good shoot quality, elongation, multiplication and medium callus formation were suggested to be: NO₃⁻ <88 mM, NH₄⁺ <20 mM, Ca²⁺ <5 mM, Mg²⁺ >5 mM and K⁺ <46 mM. Another step of the research was to develop a reliable and economical fingerprinting set consisting of high core-repeat SSRs (≥3) for genotype identification of 102 hazelnut accessions. Identification of trueness-to-type by phenotypic observation is very difficult and labeling mistakes during the several steps of micropropagation can result in costly errors. The use of SSRs for plant identification is preferred over other molecular markers because they are reproducible across laboratories, exhibit co-dominant inheritance, have a large number of alleles per locus and are randomly distributed throughout the genome. Twenty SSRs containing repeat motifs of three or more nucleotides distributed throughout the hazelnut genome were screened on eight genetically diverse cultivars to assess polymorphism, allele size range, and ease of scoring. Six SSRs were discarded after genotyping 96 hazelnut samples, either due to large allele bin widths and/or alleles that do not match the motifs, complicating allele scoring. Fourteen polymorphic, easy-to-score SSRs with non-overlapping alleles were selected and amplified in a single multiplex. The multiplexed set generated the same alleles that were obtained when amplifying each SSR individually in the eight test accessions. SSR primer concentrations were then optimized to generate a clear signal for each locus. This 14-SSR fingerprinting set was used to genotype 102 hazelnut accessions, and distinguished unique accessions mainly according to parentage and in some cases based on geographic origin. As a result of these studies, salt- and ion-based optimized tissue culture medium formulations were developed for diverse hazelnuts. The importance of salts and ions as factors within the experimental design and analysis was examined, and using salts as factors results in complexity within the design as the effects of ions can not be determined. Although salt optimization studies are still a powerful tool, and are experimentally easier, optimization at the ionic level provided a clearer evaluation of the ion-based growth responses, because the plants take up minerals as ions of the corresponding salts. Data mining (CHAID) was used to make the tissue culture optimization process more practical compared to analysis with the standard ANOVA, regression and RSM. CHAID delineated specific concentrations that were effective and allowed easier analysis of nutrient content for an improved medium. A reliable and cost-effective multiplexed fingerprinting set of 14 SSR markers was developed for confirming identity and paternity in diverse hazelnut cultivars and species and 102 accessions were fingerprinted. Close

• 2233. [Article] Potentiation of acute carbon tetrachloride hepatotoxicity by dietary exposure to chlorophenothane (DDT) in rats

  There has been no toxicologic proof that the long-term, low-level exposure of man to chlorophenothane (DDT) is linked with an increased susceptibility to toxicity or disease. Acute pretreatment of rats ...

  Citation × Citation Citation Abstract Copy Title: Potentiation of acute carbon tetrachloride hepatotoxicity by dietary exposure to chlorophenothane (DDT) in rats Author: Koeferl, Michael Tallyn There has been no toxicologic proof that the long-term, low-level exposure of man to chlorophenothane (DDT) is linked with an increased susceptibility to toxicity or disease. Acute pretreatment of rats with 75-100 mg/kg DDT has been demonstrated to potentiate CCI₄-induced hepatotoxicity in that species (McLean and McLean, 1966). Since the hepatotoxic response to CC1₄ is similar among mammalian species, it was believed man's response could also be altered by prior exposure to DDT. Chronic pretreatment of rats with DDT more closely duplicates man's exposure situation, which is mainly dietary. Therefore, this present investigation was undertaken to quantify the DDT-CCI₄ hepatotoxic interaction in rats from the standpoint of a chronic dietary exposure to DDT. Chronic and acute pretreatments with DDT were compared for their relative effects on acute CC1₄ hepatotoxicity. Subgroups of rats fed DDT at concentrations of 6-65 ppm for three weeks and 65 ppm for 24 weeks attained body burdens of DDT and its metabolites ranging from 6.1 to 30.6 ppm, compared to 0 ppm (no detectable) for controls. In the acute study, subgroups of rats were dosed with 35-150 mg/kg DDT by gavage 24 hours prior to CC1₄ exposure. Doses of CC1₄ ranging from 0.125 to 1.0 mi./kg were administered by gavage. All pretreatments with DDT, chronic or acute, resulted in a potentiated elevation of serum transaminase (SGPT and SGOT) activities following treatment with CC1₄. The degree of potentiation was dose-related to CCI₄ and to the total DDT body burden. In a temporal study, the onset of the potentiated response was noted six hours after CC1₄. All of the above-mentioned results were confirmed by histopathology. Plasma BSP disappearance, dose-response and temporal studies were conducted in control and DDT-fed rat groups, utilizing the BSP test as an index of hepatic functional impairment, CC1₄-induced BSP retention was greatly potentiated by prior dietary exposure to DDT. This potentiation effect was obscured at a dose of 2.0 ml/kg CC1₄, due to the severe hepatic damage produced by this dose of CCI₄ given alone. The onset and development of the potentiated hepatic dysfunction paralleled that of the parenchymal cell destruction. The potentiated CC1₄-induced increases in SGOT activity and centrilobularly-oriented coagulative necrosis in the DDT-fed animals were prevented by spinal cord transection at the level of the seventh cervical vertebra. Chronic DDT pretreatment did not enhance CC1₄ uptake into the blood or livers of intact rats, and this was ruled out as a possible mechanism for the potentiation effect. Cord-sectioning did enhance tissue CC1₄ uptake, yet these animals were protected against CC1₄-induced central necrosis. Neither cord-sectioning nor the resultant hypothermia reduced the microsomal cytochrome P-450 content in control or DDT-fed rats. Hypothermia depressed the in vitro N-demethylation of ethylmorphine, so that oxidative drug metabolism was probably also decreased in vivo in the cordotomized animals. Maximal blood and liver concentrations of CC1₄ were measured between 2-4 hours in the intact control and DDT-fed groups. These tissue CC1₄ concentrations decreased more rapidly between 4-12 hours in the DDT-fed rats, thus suggesting an increased rate of CC1₄ metabolism could have occurred at this time in vivo in these animals. Unlike the other indices of hepatic damage, the cytochrome P-450 response preceded rather than followed the hepatocellular destruction. About 75% of the induced cytochrome P-450 concentration in the DDTfed rats was destroyed within six hours after CC1₄, at which time the onset of potentiated hepatic damage was detected. In the controls, the cytochrome P-450 concentration regenerated from a low value at 18 hours to normal by 48 hours after CC1₄. Hepatic regeneration was impaired in the DDT-fed rats, since the cytochrome P-450 concentration continued to decline between 24-48 hours. The amount of cytochrome P-450 destruction appeared to correlate with the degree of hepatic damage observed. Lower absolute concentrations of cytochrome P-450 were measured in controls 24 hours after dosing with 0.125-2.0 ml/kg CC1₄. More cytochrome P-450 was destroyed in the DDT-fed group, however, as a result of the induced microsomal concentrations of this cytochrome present initially before CC1₄ was given. Thus, the CCI₄- cytochrome P-450 interaction could play an integral role in the potentiation phenomenon, as McLean and McLean (1969) have suggested. Liver weight increased in a dose-related manner to CC1₄ in both control and DDT-fed groups, but the response was greater in controls. In the control animals, the liver weight increased rapidly to a maximal value at 18 hours, but returned to normal by 48 hours after CC1₄. Although the onset of the response was slower in the DDT-fed rats, the liver weight continued to increase at 48 hours. Rectal temperatures declined between 6-24 hours only in the DDT-fed animals. The pharmacologic agents SKF 525-A (drug metabolism inhibitor) and lead (porphyrin biosynthesis inhibitor) were utilized to assess the role of cytochrome P-450 in potentiation. SKF 525-A provided protection against the potentiated CC1₄-induced centrilobular necrosis at 11 hours after CC1₄. This protection could not be positively ascribed to SKF 525-A binding with cytochrome P-450 or inhibiting CC1₄ metabolism, since SKF 525-A has been reported to alter the gastrointestinal absorption of CC1₄ (Marchand, McLean and Plaa, 1970). Lead significantly reduced the effect of prior DDT feeding in potentiating CC1₄ hepatotoxicity, but this protection did not result from a lowered microsomal cytochrome P-450 content. Thus, the role of cytochrome P-450 in the potentiation effect remains to be conclusively elucidated. Mecamylamine pretreatment was used to determine the importance of the sympathomimetic properties of DDT in potentiation. This ganglionic blocking agent produced an insignificant tendency to decrease the potentiated CC1₄- induced BSP retention. However, the histologic evidence of protection against CC1₄ -induced hepatic necrosis was not apparent in mecamylamine-pretreated animals. Thus, the central sympathetic nervous system stimulatory effects of DDT are probably not directly involved in potentiation. The basis for extrapolation of these results from rat to man could be the total DDT body burden, which was similar in these rats (6.1 -30.6 ppm) to that estimated for man, e.g., 10 ppm by Durham (1965). Since rats and man respond similarly to CC1₄, these results indicate that man's chronic exposure to DDT could render him highly susceptible to a secondary exposure to CC1₄. Title: Potentiation of acute carbon tetrachloride hepatotoxicity by dietary exposure to chlorophenothane (DDT) in rats Author: Koeferl, Michael Tallyn There has been no toxicologic proof that the long-term, low-level exposure of man to chlorophenothane (DDT) is linked with an increased susceptibility to toxicity or disease. Acute pretreatment of rats with 75-100 mg/kg DDT has been demonstrated to potentiate CCI₄-induced hepatotoxicity in that species (McLean and McLean, 1966). Since the hepatotoxic response to CC1₄ is similar among mammalian species, it was believed man's response could also be altered by prior exposure to DDT. Chronic pretreatment of rats with DDT more closely duplicates man's exposure situation, which is mainly dietary. Therefore, this present investigation was undertaken to quantify the DDT-CCI₄ hepatotoxic interaction in rats from the standpoint of a chronic dietary exposure to DDT. Chronic and acute pretreatments with DDT were compared for their relative effects on acute CC1₄ hepatotoxicity. Subgroups of rats fed DDT at concentrations of 6-65 ppm for three weeks and 65 ppm for 24 weeks attained body burdens of DDT and its metabolites ranging from 6.1 to 30.6 ppm, compared to 0 ppm (no detectable) for controls. In the acute study, subgroups of rats were dosed with 35-150 mg/kg DDT by gavage 24 hours prior to CC1₄ exposure. Doses of CC1₄ ranging from 0.125 to 1.0 mi./kg were administered by gavage. All pretreatments with DDT, chronic or acute, resulted in a potentiated elevation of serum transaminase (SGPT and SGOT) activities following treatment with CC1₄. The degree of potentiation was dose-related to CCI₄ and to the total DDT body burden. In a temporal study, the onset of the potentiated response was noted six hours after CC1₄. All of the above-mentioned results were confirmed by histopathology. Plasma BSP disappearance, dose-response and temporal studies were conducted in control and DDT-fed rat groups, utilizing the BSP test as an index of hepatic functional impairment, CC1₄-induced BSP retention was greatly potentiated by prior dietary exposure to DDT. This potentiation effect was obscured at a dose of 2.0 ml/kg CC1₄, due to the severe hepatic damage produced by this dose of CCI₄ given alone. The onset and development of the potentiated hepatic dysfunction paralleled that of the parenchymal cell destruction. The potentiated CC1₄-induced increases in SGOT activity and centrilobularly-oriented coagulative necrosis in the DDT-fed animals were prevented by spinal cord transection at the level of the seventh cervical vertebra. Chronic DDT pretreatment did not enhance CC1₄ uptake into the blood or livers of intact rats, and this was ruled out as a possible mechanism for the potentiation effect. Cord-sectioning did enhance tissue CC1₄ uptake, yet these animals were protected against CC1₄-induced central necrosis. Neither cord-sectioning nor the resultant hypothermia reduced the microsomal cytochrome P-450 content in control or DDT-fed rats. Hypothermia depressed the in vitro N-demethylation of ethylmorphine, so that oxidative drug metabolism was probably also decreased in vivo in the cordotomized animals. Maximal blood and liver concentrations of CC1₄ were measured between 2-4 hours in the intact control and DDT-fed groups. These tissue CC1₄ concentrations decreased more rapidly between 4-12 hours in the DDT-fed rats, thus suggesting an increased rate of CC1₄ metabolism could have occurred at this time in vivo in these animals. Unlike the other indices of hepatic damage, the cytochrome P-450 response preceded rather than followed the hepatocellular destruction. About 75% of the induced cytochrome P-450 concentration in the DDTfed rats was destroyed within six hours after CC1₄, at which time the onset of potentiated hepatic damage was detected. In the controls, the cytochrome P-450 concentration regenerated from a low value at 18 hours to normal by 48 hours after CC1₄. Hepatic regeneration was impaired in the DDT-fed rats, since the cytochrome P-450 concentration continued to decline between 24-48 hours. The amount of cytochrome P-450 destruction appeared to correlate with the degree of hepatic damage observed. Lower absolute concentrations of cytochrome P-450 were measured in controls 24 hours after dosing with 0.125-2.0 ml/kg CC1₄. More cytochrome P-450 was destroyed in the DDT-fed group, however, as a result of the induced microsomal concentrations of this cytochrome present initially before CC1₄ was given. Thus, the CCI₄- cytochrome P-450 interaction could play an integral role in the potentiation phenomenon, as McLean and McLean (1969) have suggested. Liver weight increased in a dose-related manner to CC1₄ in both control and DDT-fed groups, but the response was greater in controls. In the control animals, the liver weight increased rapidly to a maximal value at 18 hours, but returned to normal by 48 hours after CC1₄. Although the onset of the response was slower in the DDT-fed rats, the liver weight continued to increase at 48 hours. Rectal temperatures declined between 6-24 hours only in the DDT-fed animals. The pharmacologic agents SKF 525-A (drug metabolism inhibitor) and lead (porphyrin biosynthesis inhibitor) were utilized to assess the role of cytochrome P-450 in potentiation. SKF 525-A provided protection against the potentiated CC1₄-induced centrilobular necrosis at 11 hours after CC1₄. This protection could not be positively ascribed to SKF 525-A binding with cytochrome P-450 or inhibiting CC1₄ metabolism, since SKF 525-A has been reported to alter the gastrointestinal absorption of CC1₄ (Marchand, McLean and Plaa, 1970). Lead significantly reduced the effect of prior DDT feeding in potentiating CC1₄ hepatotoxicity, but this protection did not result from a lowered microsomal cytochrome P-450 content. Thus, the role of cytochrome P-450 in the potentiation effect remains to be conclusively elucidated. Mecamylamine pretreatment was used to determine the importance of the sympathomimetic properties of DDT in potentiation. This ganglionic blocking agent produced an insignificant tendency to decrease the potentiated CC1₄- induced BSP retention. However, the histologic evidence of protection against CC1₄ -induced hepatic necrosis was not apparent in mecamylamine-pretreated animals. Thus, the central sympathetic nervous system stimulatory effects of DDT are probably not directly involved in potentiation. The basis for extrapolation of these results from rat to man could be the total DDT body burden, which was similar in these rats (6.1 -30.6 ppm) to that estimated for man, e.g., 10 ppm by Durham (1965). Since rats and man respond similarly to CC1₄, these results indicate that man's chronic exposure to DDT could render him highly susceptible to a secondary exposure to CC1₄. Close

• 2234. [Article] Geology of the Hamlet-North Fork of the Nehalem River area, southern Clatsop and northernmost Tillamook Counties, northwest Oregon

  The middle to late Eocene tholeiitic Tillamook Volcanics compose the oldest rock unit in the Hamlet-North Fork of the Nehalem River area. Geochemical plots and field relationships indicate that these rocks ...

  Citation × Citation Citation Abstract Copy Title: Geology of the Hamlet-North Fork of the Nehalem River area, southern Clatsop and northernmost Tillamook Counties, northwest Oregon Author: Rarey, Phillip Jay The middle to late Eocene tholeiitic Tillamook Volcanics compose the oldest rock unit in the Hamlet-North Fork of the Nehalem River area. Geochemical plots and field relationships indicate that these rocks were produced in an extensional tectonic setting in the developing forearc and formed an extensive tholeiltic oceanic island. The volcanics consi5t of a thick sequence of normally and reversely polarized subaerial basalt and basaltic andesite flows in the Hamlet-North Fork of the Nehalem River area. The "Gray's River area" Goble Volcanics in southwest Washington are chemically and stratigraphically correlative to the Tillamook Volcanics. Cessation of Tillamook volcanism resulted in thermal subsidence and transgression of the overlying Hamlet formation. Upper Narizian (middle to upper Eccene) nearshore fossiliferous basaltic boulder-pebble conglomerates and basaltic sandstones of the Roy Creek member of the Hamlet formation (informal) were deposited along a rocky basaltic coastline over the subsiding volcanic "island". Scanning electron microscopy shows that radial pore-filling chloritic cement has significantly reduced porosity in Roy Creek member sandstones. Micaceous and carbonaceous silty mudstones and rare thin basaltic turbidite sandstones of the Sweet Home Creek member of the Hamlet formation (informal> were deposited on the outer shelf to upper slope above the Roy Creek member as the basin continued to deepen. The Sweet Home Creek member contains abundant bathyal benthtc foraminifera assignable to the upper Narizian stage. Calcareous nannofossils collected from the unit have been assigned to subzone CP-14a which is in agreement with foraminifera data. The upper part of the Sweet Home Creek member is in part a deep marine correlative to shelf arkosic sandstones of the Cowltiz Formation which pinches out into the Sweet Home Creek member in eastern Clatsop County. Much of the detritus in the Sweet Home Creek member was derived from plutonic and metamorphic sources in contrast to the locally derived Roy Creek member. Calc-alkaline Cole Mountain basalt (informal) intrudes and overlies the Sweet Home Creek member. Cole Mountain basalt was formed in a compressional tectonic environment and emplaced on the outer continental shelf as shallow intrusions and submarine flow. The unit is chemically and petrographically distinct from the Tillamook Volcanics and chemically similar to and stratigraphically correlative to the type Goble Volcanics (e.g. low Ti02 and low P205). Unconformably overlying the Cole Mountain basalt and the Sweet Home Creek member is the bathyal, Refugian (upper Eocene), Jewell member of the Keasey Formation. It consists of three parts a basal glauconitic sandstone-siltstone, a laminated tuffaceous sandstone unit with rare small arkosic sandstone channels and occasional clastic dikes, and an upper laminated to bioturbated tuffaceous silt-mudstone. trkosic sandstones were derived from an ancesteral Columbia River system whereas abundant tuffaceous detritus was derived locally from the Cascade arc. The Refugian lower Smuggler Cove formation (informal) gradationally overlies the Jewell member and consists of bioturbated, tuffaceous, bathyal mudstones. Outer shelf, very fine-grained tuffaceous sandstones of the David Douglas tongue (informal) of the Pittsburg Bluff Formation and deeper marine correlative outer shelf to upper slope glauconitic sanstones of the middle Smuggler Cove formation overlie the lower Smuggler Cove formation. The upper Smuggler Cove formation consists of uppermost Refugian to Zemmorian bathyal, bioturbated, fossiliferous, well-indurated tuffaceous siltstone. Laminated carbonaceous mudetones and thin (<1/2 m) arkosic sandstone beds of the ball park unit in the Smuggler Cove formation overlie and interfinger with (7) the upper Smuggler Cove formation. The ball park unit is late Zemorrian (Oligocene) or Saucesian (Early Miocene) in age. Fluvial-deltaic to shallow marine sandstones and conglomerates of the lower to middle Miocene angora Peek member of the astoria Formation unconformably overlies the Smuggler Cove formation. Numerous middle to upper Miocene basalts and gabbros intrude the sedimentary rocks in the thesis area. The intrusive rocks are chemically, magnetically, petrographically, and chronologically correlative to the Grande Ronde Basalt, Frenchman Springs Member, and Pomona Member of the Columbia River Basalt Group on the Columbia Plateau. The Grande Ronde Basalt intrusives have been divided into three chemical-magnetostratigraphic units in the thesis area and correlated to subaerial Columbia River Basalt flows located approximately 35 km to the northeast. The intrusive rocks are thought to have formed by invasion of voluminous subaerial flows into soft, semiconsolidated marine sediments as first envisioned by Beeson et. al. (1979). Uplift of the Coast Range forearc ridge from late Miocene to present has resulted in subaerial erosion and exposure of rock units. Thin alluvial gravels and sands were deposited in the southeastern corner of the thesis area during the Quaternary. Structure in the thesis area is dominated by a series of east-west trending high angle faults and a younger series of conjugate northeast-and northwest-trending high angle oblique slip faults. Proton precession magnetometer traverses confirm the presence of the faults. The structure may have been produced by partial coupling of the forearc region with the subducting Farallon plate. The thesis area has been actively explored for hydrocarbons. Geologic mapping, however, shows that significant sandstone reservoirs are not present in the subsurface and, therefore, the area has low potential of hydrocarbon production. Mudstones in the thesis area average approximately 0.9-1.1% total organic carbon with vitrinite reflectance values ranging from 0.53% Ro (unbaked) to 0.72% Ro (baked). Therefore, the mudstones are a marginal to poor source of thermogenic gas but a possible source of methane gas. Title: Geology of the Hamlet-North Fork of the Nehalem River area, southern Clatsop and northernmost Tillamook Counties, northwest Oregon Author: Rarey, Phillip Jay The middle to late Eocene tholeiitic Tillamook Volcanics compose the oldest rock unit in the Hamlet-North Fork of the Nehalem River area. Geochemical plots and field relationships indicate that these rocks were produced in an extensional tectonic setting in the developing forearc and formed an extensive tholeiltic oceanic island. The volcanics consi5t of a thick sequence of normally and reversely polarized subaerial basalt and basaltic andesite flows in the Hamlet-North Fork of the Nehalem River area. The "Gray's River area" Goble Volcanics in southwest Washington are chemically and stratigraphically correlative to the Tillamook Volcanics. Cessation of Tillamook volcanism resulted in thermal subsidence and transgression of the overlying Hamlet formation. Upper Narizian (middle to upper Eccene) nearshore fossiliferous basaltic boulder-pebble conglomerates and basaltic sandstones of the Roy Creek member of the Hamlet formation (informal) were deposited along a rocky basaltic coastline over the subsiding volcanic "island". Scanning electron microscopy shows that radial pore-filling chloritic cement has significantly reduced porosity in Roy Creek member sandstones. Micaceous and carbonaceous silty mudstones and rare thin basaltic turbidite sandstones of the Sweet Home Creek member of the Hamlet formation (informal> were deposited on the outer shelf to upper slope above the Roy Creek member as the basin continued to deepen. The Sweet Home Creek member contains abundant bathyal benthtc foraminifera assignable to the upper Narizian stage. Calcareous nannofossils collected from the unit have been assigned to subzone CP-14a which is in agreement with foraminifera data. The upper part of the Sweet Home Creek member is in part a deep marine correlative to shelf arkosic sandstones of the Cowltiz Formation which pinches out into the Sweet Home Creek member in eastern Clatsop County. Much of the detritus in the Sweet Home Creek member was derived from plutonic and metamorphic sources in contrast to the locally derived Roy Creek member. Calc-alkaline Cole Mountain basalt (informal) intrudes and overlies the Sweet Home Creek member. Cole Mountain basalt was formed in a compressional tectonic environment and emplaced on the outer continental shelf as shallow intrusions and submarine flow. The unit is chemically and petrographically distinct from the Tillamook Volcanics and chemically similar to and stratigraphically correlative to the type Goble Volcanics (e.g. low Ti02 and low P205). Unconformably overlying the Cole Mountain basalt and the Sweet Home Creek member is the bathyal, Refugian (upper Eocene), Jewell member of the Keasey Formation. It consists of three parts a basal glauconitic sandstone-siltstone, a laminated tuffaceous sandstone unit with rare small arkosic sandstone channels and occasional clastic dikes, and an upper laminated to bioturbated tuffaceous silt-mudstone. trkosic sandstones were derived from an ancesteral Columbia River system whereas abundant tuffaceous detritus was derived locally from the Cascade arc. The Refugian lower Smuggler Cove formation (informal) gradationally overlies the Jewell member and consists of bioturbated, tuffaceous, bathyal mudstones. Outer shelf, very fine-grained tuffaceous sandstones of the David Douglas tongue (informal) of the Pittsburg Bluff Formation and deeper marine correlative outer shelf to upper slope glauconitic sanstones of the middle Smuggler Cove formation overlie the lower Smuggler Cove formation. The upper Smuggler Cove formation consists of uppermost Refugian to Zemmorian bathyal, bioturbated, fossiliferous, well-indurated tuffaceous siltstone. Laminated carbonaceous mudetones and thin (<1/2 m) arkosic sandstone beds of the ball park unit in the Smuggler Cove formation overlie and interfinger with (7) the upper Smuggler Cove formation. The ball park unit is late Zemorrian (Oligocene) or Saucesian (Early Miocene) in age. Fluvial-deltaic to shallow marine sandstones and conglomerates of the lower to middle Miocene angora Peek member of the astoria Formation unconformably overlies the Smuggler Cove formation. Numerous middle to upper Miocene basalts and gabbros intrude the sedimentary rocks in the thesis area. The intrusive rocks are chemically, magnetically, petrographically, and chronologically correlative to the Grande Ronde Basalt, Frenchman Springs Member, and Pomona Member of the Columbia River Basalt Group on the Columbia Plateau. The Grande Ronde Basalt intrusives have been divided into three chemical-magnetostratigraphic units in the thesis area and correlated to subaerial Columbia River Basalt flows located approximately 35 km to the northeast. The intrusive rocks are thought to have formed by invasion of voluminous subaerial flows into soft, semiconsolidated marine sediments as first envisioned by Beeson et. al. (1979). Uplift of the Coast Range forearc ridge from late Miocene to present has resulted in subaerial erosion and exposure of rock units. Thin alluvial gravels and sands were deposited in the southeastern corner of the thesis area during the Quaternary. Structure in the thesis area is dominated by a series of east-west trending high angle faults and a younger series of conjugate northeast-and northwest-trending high angle oblique slip faults. Proton precession magnetometer traverses confirm the presence of the faults. The structure may have been produced by partial coupling of the forearc region with the subducting Farallon plate. The thesis area has been actively explored for hydrocarbons. Geologic mapping, however, shows that significant sandstone reservoirs are not present in the subsurface and, therefore, the area has low potential of hydrocarbon production. Mudstones in the thesis area average approximately 0.9-1.1% total organic carbon with vitrinite reflectance values ranging from 0.53% Ro (unbaked) to 0.72% Ro (baked). Therefore, the mudstones are a marginal to poor source of thermogenic gas but a possible source of methane gas. Close

• 2235. [Article] Land use distributions and changes in the Willamette Valley in relation to soil characteristics

  A study was undertaken in the Willamette Valley, Oregon, to document 1971 land use patterns as well as land use change in a smaller study area in the 16 years prior, and to relate these to soil characteristics. Quantification ...

  Citation × Citation Citation Abstract Copy Title: Land use distributions and changes in the Willamette Valley in relation to soil characteristics Author: Wiens, John Herbert A study was undertaken in the Willamette Valley, Oregon, to document 1971 land use patterns as well as land use change in a smaller study area in the 16 years prior, and to relate these to soil characteristics. Quantification of these inter-relationships was aided by use of computer tabulation and graphic methods. Use of the data base generated and methods developed was expanded somewhat and applied to calculation and mapping of composite indices of suitabilities and limitations of soils for selected uses. Mapping of land use for 1971 and 1955 was done on color and black and white photos respectively, having a scale of about 1:62,500. To avoid creating artificial, apparent land use changes by differences in delineation and classification, mapping was done first on the higher quality 1971 color photos and then by comparison on 1955 black and white photos. Importance of various photo-interpretive factors to legend development and consistent delineation and classification became apparent and was documented. The legend utilized was, with some modification, the 1972 U.S.G.S. proposed national system for use with remote sensor data. To facilitate comparison of land use and land use change with soil survey map information, photo mapped land use information and available soil association map information was transferred to transparent mylar film over planimetric U.S.G.S. 15' topographic quadrangle sheets. This also allowed use of the square, 1000 meter Universal Transverse Mercator (UTM) grid as reference for point sampling and geo-referenced coding of land use and soil information for computer storage. Tabulation of land use classes for the entire study area for 1971 showed the largest proportion of land to be in agricultural (53.5 percent) and forest land (38 percent) use. A further 6.5 percent was in urban use. Within the selected townships of the land use change study area the proportions were different; 65.7 percent, 14.3 percent and 17.2 percent for agricultural, forest, and urban uses respectively. Analysis of changes in land use between 1955 and 1971 in the land use change study area was done by means of transition matrices; diagonal elements represent areas of land not subject to change; off diagonal elements represent components of change. In total, between 55.9 and 72.4 percent of the land in the area studied experienced no use change, the range being due to uncertainty of classification of some land on the 1955 black and white photos. Urbanization was shown to have occurred largely at the expense of agricultural land and particularly non-irrigated cropland, pasture and orchard land uses. Some conversion of forest to urban land use (0.9 percent of the area) was documented, however. The most significant agricultural use change was a net increase in irrigated land of between 5 and 8.4 percent. A net decrease in orchard land was also recorded. Land use for 1971, not unexpectedly, showed significant concentration in certain physiographic areas and in areas with particular soil characteristics. Thus for example, urban uses were found more frequently than expected on valley-floor and stream-cut terraces, and forest land uses more frequently on foothills and mountainous uplands. Irrigated cropland was somewhat concentrated on soils in sandy, coarse loamy, coarse silty and fine silty particle size classes. Urban and cropland agriculture use classes have obviously avoided steeply sloping areas. Irrigated cropland and orchard land uses have avoided soil areas with high shrink-swell potential whereas grass seed producing croplands have not. Numerous other examples could be given. In summary, Chi-square analysis on the contigency tables of land use class and physical land characteristic classes gave highly significant values (eg. for 1971 land use/physiographic areas x ² calc = 9108.25 and x ² tab = 137.68), and thus the null hypotheses of no association between land use classification and these physical land characteristics were rejected. Three-way tabulation of soil characteristics and physiographic area classification against 1971 and 1955 land use classification allowed analysis of land use change in relation to these physical properties. The idea of composite model soils was used to provide a framework for summary of the kinds of soils subject to smallest and largest changes in particular kinds of urban, agricultural, and forest land uses. As examples, it appeared that greatest relative increases of residential and industrial uses occurred on poorly drained, fine textured, slowly permeable soils; greatest relative losses of agricultural land occurred on soils having the highest capability for agriculture, and; greatest relative increases in irrigation cropland uses occurred on soils rated good to excellent for irrigation. Other examples and trends were observed. A method for computer calculation of composite soil suitability or limitation indices for various uses was developed. Ranked indices were compared to interpretive groupings by best subjective judgement. Class frequency correlations were found to be generally good. Indices were further mapped using a computer graphics system, GRIDS. The index calculation method interfaced with a mapping capability was shown to have potential for rapid, flexible display of various soil, land use, as well as soil and land use patterns for land use planning purposes. Title: Land use distributions and changes in the Willamette Valley in relation to soil characteristics Author: Wiens, John Herbert A study was undertaken in the Willamette Valley, Oregon, to document 1971 land use patterns as well as land use change in a smaller study area in the 16 years prior, and to relate these to soil characteristics. Quantification of these inter-relationships was aided by use of computer tabulation and graphic methods. Use of the data base generated and methods developed was expanded somewhat and applied to calculation and mapping of composite indices of suitabilities and limitations of soils for selected uses. Mapping of land use for 1971 and 1955 was done on color and black and white photos respectively, having a scale of about 1:62,500. To avoid creating artificial, apparent land use changes by differences in delineation and classification, mapping was done first on the higher quality 1971 color photos and then by comparison on 1955 black and white photos. Importance of various photo-interpretive factors to legend development and consistent delineation and classification became apparent and was documented. The legend utilized was, with some modification, the 1972 U.S.G.S. proposed national system for use with remote sensor data. To facilitate comparison of land use and land use change with soil survey map information, photo mapped land use information and available soil association map information was transferred to transparent mylar film over planimetric U.S.G.S. 15' topographic quadrangle sheets. This also allowed use of the square, 1000 meter Universal Transverse Mercator (UTM) grid as reference for point sampling and geo-referenced coding of land use and soil information for computer storage. Tabulation of land use classes for the entire study area for 1971 showed the largest proportion of land to be in agricultural (53.5 percent) and forest land (38 percent) use. A further 6.5 percent was in urban use. Within the selected townships of the land use change study area the proportions were different; 65.7 percent, 14.3 percent and 17.2 percent for agricultural, forest, and urban uses respectively. Analysis of changes in land use between 1955 and 1971 in the land use change study area was done by means of transition matrices; diagonal elements represent areas of land not subject to change; off diagonal elements represent components of change. In total, between 55.9 and 72.4 percent of the land in the area studied experienced no use change, the range being due to uncertainty of classification of some land on the 1955 black and white photos. Urbanization was shown to have occurred largely at the expense of agricultural land and particularly non-irrigated cropland, pasture and orchard land uses. Some conversion of forest to urban land use (0.9 percent of the area) was documented, however. The most significant agricultural use change was a net increase in irrigated land of between 5 and 8.4 percent. A net decrease in orchard land was also recorded. Land use for 1971, not unexpectedly, showed significant concentration in certain physiographic areas and in areas with particular soil characteristics. Thus for example, urban uses were found more frequently than expected on valley-floor and stream-cut terraces, and forest land uses more frequently on foothills and mountainous uplands. Irrigated cropland was somewhat concentrated on soils in sandy, coarse loamy, coarse silty and fine silty particle size classes. Urban and cropland agriculture use classes have obviously avoided steeply sloping areas. Irrigated cropland and orchard land uses have avoided soil areas with high shrink-swell potential whereas grass seed producing croplands have not. Numerous other examples could be given. In summary, Chi-square analysis on the contigency tables of land use class and physical land characteristic classes gave highly significant values (eg. for 1971 land use/physiographic areas x ² calc = 9108.25 and x ² tab = 137.68), and thus the null hypotheses of no association between land use classification and these physical land characteristics were rejected. Three-way tabulation of soil characteristics and physiographic area classification against 1971 and 1955 land use classification allowed analysis of land use change in relation to these physical properties. The idea of composite model soils was used to provide a framework for summary of the kinds of soils subject to smallest and largest changes in particular kinds of urban, agricultural, and forest land uses. As examples, it appeared that greatest relative increases of residential and industrial uses occurred on poorly drained, fine textured, slowly permeable soils; greatest relative losses of agricultural land occurred on soils having the highest capability for agriculture, and; greatest relative increases in irrigation cropland uses occurred on soils rated good to excellent for irrigation. Other examples and trends were observed. A method for computer calculation of composite soil suitability or limitation indices for various uses was developed. Ranked indices were compared to interpretive groupings by best subjective judgement. Class frequency correlations were found to be generally good. Indices were further mapped using a computer graphics system, GRIDS. The index calculation method interfaced with a mapping capability was shown to have potential for rapid, flexible display of various soil, land use, as well as soil and land use patterns for land use planning purposes. Close

• 2236. [Article] Physiological Responses of Loblolly Pine and Douglas-fir Seedlings from Various Provenances to Timing and Frequency of Drought Stress

  Drought is expected to increase in many parts of the world and has been shown to affect tree physiology and growth, with seedlings being particularly vulnerable. Seedling drought responses are often species ...

  Citation × Citation Citation Abstract Copy Title: Physiological Responses of Loblolly Pine and Douglas-fir Seedlings from Various Provenances to Timing and Frequency of Drought Stress Author: Mosel, Jamie E. Drought is expected to increase in many parts of the world and has been shown to affect tree physiology and growth, with seedlings being particularly vulnerable. Seedling drought responses are often species dependent, and even within species different populations may demonstrate a spectrum of responses to drought, from susceptibility to resistance. As both loblolly pine (Pinus taeda) and Douglas-fir (Pseudotsuga menziesii) have broad geographic ranges, they provide an opportunity to assess drought resistances of provenances associated with a variety of site climate conditions across their ranges. Furthermore, while studies of singular drought events have revealed important information about seedling stress responses, it has been shown that drought may impart effects even following the release from drought. In some cases, effects of drought exposure can be detrimental or lethal; however, exposure to non-lethal drought may also lead to drought acclimation, which could potentially enhance seedling functioning under subsequent droughts. This potential phenotypic plasticity, i.e. the extent to which a seedling can acclimate to drought conditions, may vary across species and across provenances within a species. This study used physiological (electron transport rate, fluorescence, and water potentials) and growth (biomass accumulation and height increment) responses for two goals: 1) to assess the drought resistances of three provenances of loblolly pine and three provenances of Douglas-fir associated with varying site climate conditions, and 2) to investigate whether previous exposure to a drought results in acclimation to a second drought. We hypothesized that: 1) drought responses would differ among the provenances in accordance with associated site climate conditions (i.e., provenances associated with mesic site climates as characterized by low climatic moisture deficit and high mean annual precipitation would be drought susceptible, and more xeric site climates as characterized by high climatic moisture deficit and low mean annual precipitation would be more drought resistant) as evidenced by physiological measures of electron transport rate, fluorescence, water potentials and growth; and 2) previous exposure to drought would result in acclimation to drought as evidenced by maintenance of physiological function (i.e., higher levels of electron transport and fluorescence) in previously drought exposed seedlings compared to previously unexposed seedlings. We also hypothesized that levels of acclimation would vary among provenances. The study yielded some evidence to support the first hypothesis regarding provenance differences in drought resistances in both species. Provenance drought resistances conformed largely to expectations, though differences were less than expected. In loblolly pine, although not statistically significant, during the second drought there was a pattern of lower maximum electron transport rates, which appeared sooner in the more mesic provenance than in the other two provenances. There were also provenance differences in seedling heights, with the most xeric of the three provenances being shorter at the beginning and the end of the study. In Douglas-fir, there were significant differences in provenance and in the interaction of treatment and provenance for maximum electron rates and fluorescence. Dark-adapted fluorescence was lower in the Coos Bay (mesic site climate) provenance during drought than in the Cascades (mesic site climate) and New Mexico (xeric site climate) provenances. The New Mexico provenance showed the least differences in fluorescence between droughted and watered treatments. The study also yielded some evidence to support the second hypothesis regarding drought acclimation in both species and among provenances. During the second drought, there was a pattern of higher maximum electron transport rates and fluorescence in previously drought exposed seedlings as compared to seedlings previously unexposed to drought. This difference was significant in the mesic provenance (North Carolina) of loblolly pine, with maximum electron transport rates significantly higher in the previously drought exposed treatment compared to the newly exposed treatment during and following the second drought. Patterns of lower electron transport rates in seedlings previously unexposed to drought compared to seedlings previously exposed to drought also appeared in Douglas-fir during the second drought, though not with statistical significance. However, the most xeric provenance showed the reverse pattern during and following the second drought, with lower maximum electron transport rates in the previously drought exposed treatment compared to the treatment previously unexposed to drought. Chlorophyll fluorescence values were significantly higher during the second drought in the previously droughted treatments compared to newly drought-exposed treatments in some provenances of loblolly pine and Douglas-fir. Lastly, seedlings exposed to an early drought had significantly lower final heights than seedlings unexposed to an early drought in both species, although the differences were greater in loblolly pine than Douglas-fir. It may be that growth acclimation, especially in the form of height reductions, influenced physiological responses during a second drought. Further studies are necessary to provide more conclusive evidence in support or against the two hypotheses. Nonetheless, this study provides valuable information on the drought responses of young, greenhouse-grown seedlings of two species that are widespread in North America and that are economically important throughout the world. Further studies in a wider range of age classes, incorporating field studies or more natural settings, may help better predict plant responses in the face of changing climate. Title: Physiological Responses of Loblolly Pine and Douglas-fir Seedlings from Various Provenances to Timing and Frequency of Drought Stress Author: Mosel, Jamie E. Drought is expected to increase in many parts of the world and has been shown to affect tree physiology and growth, with seedlings being particularly vulnerable. Seedling drought responses are often species dependent, and even within species different populations may demonstrate a spectrum of responses to drought, from susceptibility to resistance. As both loblolly pine (Pinus taeda) and Douglas-fir (Pseudotsuga menziesii) have broad geographic ranges, they provide an opportunity to assess drought resistances of provenances associated with a variety of site climate conditions across their ranges. Furthermore, while studies of singular drought events have revealed important information about seedling stress responses, it has been shown that drought may impart effects even following the release from drought. In some cases, effects of drought exposure can be detrimental or lethal; however, exposure to non-lethal drought may also lead to drought acclimation, which could potentially enhance seedling functioning under subsequent droughts. This potential phenotypic plasticity, i.e. the extent to which a seedling can acclimate to drought conditions, may vary across species and across provenances within a species. This study used physiological (electron transport rate, fluorescence, and water potentials) and growth (biomass accumulation and height increment) responses for two goals: 1) to assess the drought resistances of three provenances of loblolly pine and three provenances of Douglas-fir associated with varying site climate conditions, and 2) to investigate whether previous exposure to a drought results in acclimation to a second drought. We hypothesized that: 1) drought responses would differ among the provenances in accordance with associated site climate conditions (i.e., provenances associated with mesic site climates as characterized by low climatic moisture deficit and high mean annual precipitation would be drought susceptible, and more xeric site climates as characterized by high climatic moisture deficit and low mean annual precipitation would be more drought resistant) as evidenced by physiological measures of electron transport rate, fluorescence, water potentials and growth; and 2) previous exposure to drought would result in acclimation to drought as evidenced by maintenance of physiological function (i.e., higher levels of electron transport and fluorescence) in previously drought exposed seedlings compared to previously unexposed seedlings. We also hypothesized that levels of acclimation would vary among provenances. The study yielded some evidence to support the first hypothesis regarding provenance differences in drought resistances in both species. Provenance drought resistances conformed largely to expectations, though differences were less than expected. In loblolly pine, although not statistically significant, during the second drought there was a pattern of lower maximum electron transport rates, which appeared sooner in the more mesic provenance than in the other two provenances. There were also provenance differences in seedling heights, with the most xeric of the three provenances being shorter at the beginning and the end of the study. In Douglas-fir, there were significant differences in provenance and in the interaction of treatment and provenance for maximum electron rates and fluorescence. Dark-adapted fluorescence was lower in the Coos Bay (mesic site climate) provenance during drought than in the Cascades (mesic site climate) and New Mexico (xeric site climate) provenances. The New Mexico provenance showed the least differences in fluorescence between droughted and watered treatments. The study also yielded some evidence to support the second hypothesis regarding drought acclimation in both species and among provenances. During the second drought, there was a pattern of higher maximum electron transport rates and fluorescence in previously drought exposed seedlings as compared to seedlings previously unexposed to drought. This difference was significant in the mesic provenance (North Carolina) of loblolly pine, with maximum electron transport rates significantly higher in the previously drought exposed treatment compared to the newly exposed treatment during and following the second drought. Patterns of lower electron transport rates in seedlings previously unexposed to drought compared to seedlings previously exposed to drought also appeared in Douglas-fir during the second drought, though not with statistical significance. However, the most xeric provenance showed the reverse pattern during and following the second drought, with lower maximum electron transport rates in the previously drought exposed treatment compared to the treatment previously unexposed to drought. Chlorophyll fluorescence values were significantly higher during the second drought in the previously droughted treatments compared to newly drought-exposed treatments in some provenances of loblolly pine and Douglas-fir. Lastly, seedlings exposed to an early drought had significantly lower final heights than seedlings unexposed to an early drought in both species, although the differences were greater in loblolly pine than Douglas-fir. It may be that growth acclimation, especially in the form of height reductions, influenced physiological responses during a second drought. Further studies are necessary to provide more conclusive evidence in support or against the two hypotheses. Nonetheless, this study provides valuable information on the drought responses of young, greenhouse-grown seedlings of two species that are widespread in North America and that are economically important throughout the world. Further studies in a wider range of age classes, incorporating field studies or more natural settings, may help better predict plant responses in the face of changing climate. Close

• 2237. [Article] Northern fur seal reproductive rates and early maternal care

  The majority of the world's breeding population of northern fur seals (Callorhinus ursinus) is found on the Pribilof Islands (St. Paul and St. George) in the Bering Sea, Alaska. Pup production on these ...

  Citation × Citation Citation Abstract Copy Title: Northern fur seal reproductive rates and early maternal care Author: Kunisch, E. (Erin) The majority of the world's breeding population of northern fur seals (Callorhinus ursinus) is found on the Pribilof Islands (St. Paul and St. George) in the Bering Sea, Alaska. Pup production on these islands experienced an irregular but overall decline since the early 1970's. Between 1998 and 2010, pup production declined precipitously at an annual rate of 4.9% on the Pribilof Islands, and 5.5% on St. Paul Island. Specific reasons for this decline remain unknown, and contemporary estimates for many vital rate parameters including reproductive rates are unavailable. This study determined a contemporary estimate of natality and fertility rates, as well as reproductive timing on the Polovina Cliffs rookery of St. Paul Island during the 2008 (30 June-31 August) and 2009 (1 July-25 August) breeding seasons. Natality rate (defined as the number of pups born divided by the number of reproductively mature females) was determined from visual observations of parturition or associated maternal behavior in 208 and 217 individually marked females (via flipper tags) in 2008 and 2009, respectively. Data yielded observed natality estimates of 0.79 in 2008 and 0.88 in 2009. The fertility rate (defined as the number of pups born divided by the total number of females present, irrespective of reproductive maturity/age) was determined for the 2008 breeding season only. This ratio of total pup to female counts was derived from adjusted daily cross-sectional counts conducted through the breeding season. Maximum pup and female counts were derived as asymptotes of sigmoid growth models fitted to corrected daily counts. Live pup counts were corrected for mortalities by estimates of cumulative pup mortalities. Daily counts of females present in the rookery were corrected for reduced detection probabilities resulting from increased maternal foraging trip durations through the season, typical of attendance patterns associated with colonial, income breeders. Daily detection probabilities for individually marked females were generated from Cormack-Jolly-Seber (CJS) open population models using maximum likelihood estimators (MLE) in Program MARK. Multiple a priori models accounting for the effects of possible covariates on detection probabilities were evaluated in an information-theoretic approach using Akaike's Information Criterion (AIC) and AICc model weights. Data yielded a minimum fertility rate estimate of 0.60 in 2008. Detection probabilities derived from the top CJS model for dual flipper-tagged females only were used to adjust the daily cross-section counts of all (marked and unmarked) females. Therefore, the actual fertility rate is probably higher than the estimate presented here, which should be regarded as the lowest likely value for 2008. However, AICc model weights also demonstrated the absence of density effects on detection probability estimates. This supports the applicability of marked female-based detection probabilities for correcting cross-sectional counts of all females and further suggests that the actual fertility estimate likely does not differ much from the presented estimate. Median dates of birth were calculated as the date closest to 50% of modeled corrected pup count asymptotes, yielding median dates of 17 July in 2008 and 15 July in 2009. Pregnant females are highly consistent in their arrival dates, with parturition occurring approximately 1 day after arrival. Median observed dates of arrival from individually marked females resulted in dates of 16 July in 2008 and 15 July in 2009. These dates occurred 5 to 13 days later than historic reports from 1951 through 1995. With median arrival dates 1 day prior to parturition, the observed match between birth dates derived from pup counts and from observed arrival dates of marked females supports the finding of a contemporary delay in the timing of parturition. Median arrival derived as the date closest to 50% of the asymptote from corrected and modeled female counts yielded 13 July in 2008. This earlier data is likely an effect of the inclusion of immature and nulli-parous females. In a subset of 62 females with pregnancy confirmed through a trans-rectal ultrasonography procedure in November 2007 and 29 females in 2008, the return rate for the following reproductive season was 0.92 and 0.76, respectively. In 2008, the return and natality rate was measured by radiotelemetry data, detected from females outfitted with VHF-radio transmitter. In 2009 both rates were determined by observational data. Observed natality rates for returned females of a known pregnancy status were 0.95 in 2008 and 0.96 in 2009. Radiotelemetry data from 76 females was analyzed for early maternal attendance patterns (duration and ratio of presences and absences) in 2008. The mean date of detected return was 18 July. The mean duration of the perinatal period was 7.5 days (+/- 1.3 SD). Excluding the perinatal period, the mean duration of presence on shore for the first five visits was 1.47 days (+/- 0.21 SD). The mean duration of absence at sea for the first five trips was 7.07 days (+/- 0.42 SD). Results presented from this study do not provide any direct evidence of a contemporary reduction in natality or fertility rates in northern fur seals. Since observed rates were comparably high and consistent between 2008 and 2009, it is unlikely that reduced natality rates are contributing to the current population trajectory. Attendance patterns do not provide any evidence of increased maternal foraging effort or secondarily, reduced prey availability. Interestingly, median pupping dates were found to occur significantly later than historical estimates. Potential reasons for this shift could be an increase in younger females within the reproductive female population at this rookery, or a shift in the timing of ocean climate conditions and peak prey availability during the breeding season. Title: Northern fur seal reproductive rates and early maternal care Author: Kunisch, E. (Erin) The majority of the world's breeding population of northern fur seals (Callorhinus ursinus) is found on the Pribilof Islands (St. Paul and St. George) in the Bering Sea, Alaska. Pup production on these islands experienced an irregular but overall decline since the early 1970's. Between 1998 and 2010, pup production declined precipitously at an annual rate of 4.9% on the Pribilof Islands, and 5.5% on St. Paul Island. Specific reasons for this decline remain unknown, and contemporary estimates for many vital rate parameters including reproductive rates are unavailable. This study determined a contemporary estimate of natality and fertility rates, as well as reproductive timing on the Polovina Cliffs rookery of St. Paul Island during the 2008 (30 June-31 August) and 2009 (1 July-25 August) breeding seasons. Natality rate (defined as the number of pups born divided by the number of reproductively mature females) was determined from visual observations of parturition or associated maternal behavior in 208 and 217 individually marked females (via flipper tags) in 2008 and 2009, respectively. Data yielded observed natality estimates of 0.79 in 2008 and 0.88 in 2009. The fertility rate (defined as the number of pups born divided by the total number of females present, irrespective of reproductive maturity/age) was determined for the 2008 breeding season only. This ratio of total pup to female counts was derived from adjusted daily cross-sectional counts conducted through the breeding season. Maximum pup and female counts were derived as asymptotes of sigmoid growth models fitted to corrected daily counts. Live pup counts were corrected for mortalities by estimates of cumulative pup mortalities. Daily counts of females present in the rookery were corrected for reduced detection probabilities resulting from increased maternal foraging trip durations through the season, typical of attendance patterns associated with colonial, income breeders. Daily detection probabilities for individually marked females were generated from Cormack-Jolly-Seber (CJS) open population models using maximum likelihood estimators (MLE) in Program MARK. Multiple a priori models accounting for the effects of possible covariates on detection probabilities were evaluated in an information-theoretic approach using Akaike's Information Criterion (AIC) and AICc model weights. Data yielded a minimum fertility rate estimate of 0.60 in 2008. Detection probabilities derived from the top CJS model for dual flipper-tagged females only were used to adjust the daily cross-section counts of all (marked and unmarked) females. Therefore, the actual fertility rate is probably higher than the estimate presented here, which should be regarded as the lowest likely value for 2008. However, AICc model weights also demonstrated the absence of density effects on detection probability estimates. This supports the applicability of marked female-based detection probabilities for correcting cross-sectional counts of all females and further suggests that the actual fertility estimate likely does not differ much from the presented estimate. Median dates of birth were calculated as the date closest to 50% of modeled corrected pup count asymptotes, yielding median dates of 17 July in 2008 and 15 July in 2009. Pregnant females are highly consistent in their arrival dates, with parturition occurring approximately 1 day after arrival. Median observed dates of arrival from individually marked females resulted in dates of 16 July in 2008 and 15 July in 2009. These dates occurred 5 to 13 days later than historic reports from 1951 through 1995. With median arrival dates 1 day prior to parturition, the observed match between birth dates derived from pup counts and from observed arrival dates of marked females supports the finding of a contemporary delay in the timing of parturition. Median arrival derived as the date closest to 50% of the asymptote from corrected and modeled female counts yielded 13 July in 2008. This earlier data is likely an effect of the inclusion of immature and nulli-parous females. In a subset of 62 females with pregnancy confirmed through a trans-rectal ultrasonography procedure in November 2007 and 29 females in 2008, the return rate for the following reproductive season was 0.92 and 0.76, respectively. In 2008, the return and natality rate was measured by radiotelemetry data, detected from females outfitted with VHF-radio transmitter. In 2009 both rates were determined by observational data. Observed natality rates for returned females of a known pregnancy status were 0.95 in 2008 and 0.96 in 2009. Radiotelemetry data from 76 females was analyzed for early maternal attendance patterns (duration and ratio of presences and absences) in 2008. The mean date of detected return was 18 July. The mean duration of the perinatal period was 7.5 days (+/- 1.3 SD). Excluding the perinatal period, the mean duration of presence on shore for the first five visits was 1.47 days (+/- 0.21 SD). The mean duration of absence at sea for the first five trips was 7.07 days (+/- 0.42 SD). Results presented from this study do not provide any direct evidence of a contemporary reduction in natality or fertility rates in northern fur seals. Since observed rates were comparably high and consistent between 2008 and 2009, it is unlikely that reduced natality rates are contributing to the current population trajectory. Attendance patterns do not provide any evidence of increased maternal foraging effort or secondarily, reduced prey availability. Interestingly, median pupping dates were found to occur significantly later than historical estimates. Potential reasons for this shift could be an increase in younger females within the reproductive female population at this rookery, or a shift in the timing of ocean climate conditions and peak prey availability during the breeding season. Close

• 2238. [Article] Selection on larval and adult body size in a marine fish: potential evolutionary responses and effects on population dynamics

  Many species have complex life cycles in which a dispersive larval stage is followed by a relatively sedentary adult stage. For such species, reproductive output is often high and large variation in survivorship ...

  Citation × Citation Citation Abstract Copy Title: Selection on larval and adult body size in a marine fish: potential evolutionary responses and effects on population dynamics Author: Johnson, Darren W. Many species have complex life cycles in which a dispersive larval stage is followed by a relatively sedentary adult stage. For such species, reproductive output is often high and large variation in survivorship throughout early life-history phases (eggs and larvae) can lead to dramatic fluctuations in recruitment which may in turn drive variation in the abundance of juveniles and adults. Early in the life cycle may therefore be a critical period for both natural selection and population dynamics. On one hand, variability in survival during early stages may provide ample opportunity for selection on early life-history traits. On the other hand, phenotypic variation in early life-history traits and selective mortality may be an important source of variability in population dynamics. Variation in survival of marine fish larvae may be a major driver of variability in benthic population size. However, little is known about how variation in larval phenotype may affect larval survival, and less in known about the evolutionary potential of marine fish larvae. I quantified both environmental and genetic sources of variation in larval traits for a field population of a common Atlantic and Caribbean coral-reef fish, the bicolor damselfish (Pomacentridae: Stegastes partitus). I combined field demographic studies and manipulative experiments in the Bahamas to estimate heritability and quantitative genetic parameters for both larval size and swimming performance – two traits that are associated with early survival. I also compiled published estimates of viability selection on larval size from eight species of fish to estimate the average magnitude of selection on this trait. The initial results of these analyses were somewhat paradoxical. Despite ample heritability (h2 = 0.29 for larval size), and strong selection on larval size (mean selection differential = 0.484), the observed mean larval size is quite far from the estimated phenotypic optimum (0.481 standard deviations greater than current mean size), suggesting that marine fish larvae are on average, maladapted with respect to survival during the larval and juvenile phases. Further analyses focused on potential evolutionary constraints on larval size. First, I estimated trade-offs in individual reproductive output between larval quality and quantity. Mothers that produced larger larvae with greater swimming abilities tended to produce fewer larvae, and these effects explained a large component of the mismatch between mean larval size and the phenotypic optimum for survival. Fluctuation in direct selection on larvae may also partially explain why mean larval size is less than optimal. Evolution of larval size may also be strongly influenced by genetic correlations with body size expressed at later ages. I demonstrated substantial additive genetic covariance between adult asymptotic size and both larval size-at-hatching and swimming performance (0.212 and 0.241 on variancestandardized traits, respectively). Adult asymptotic size was also linked to larval traits via size-dependent maternal effects, in which larger mothers provisioned offspring with more yolk resources. Selection on adult body size may therefore cause a substantial correlated genetic response in larval size that may strongly affect the overall evolutionary trajectory of larval traits. I also examined natural selection on body size and growth form in S. partitus. Using data on size, growth and longevity of individual fish studied at 4 sites over a 7-year period, I analyzed both ontogenetic and spatial variation in the magnitude and direction of viability selection on body size. Selection on asymptotic (adult) size was strong and positive at some sites, but weak and negative at other sites. Moreover, fish that were small as juveniles generally experienced greater survival, even if large adult size conferred survival benefits later in life. Both spatial and ontogenetic reversals in selection on body size would be expected to produce similar reversals in the direction of correlated responses of larvae, thereby altering the evolutionary response of larvae and potentially preventing larval size from evolving toward its optimum value. Although this research identified several potential constraints on the evolution of larval traits, there is still considerable scope for an evolutionary response to selection, especially if selection is consistent and strong. Many marine fishes are subject to size-selective fishing where larger, fast-growing individuals are selectively removed from the population. Such effects are usually strong because fishing mortality rates can greatly exceed natural mortality rates and fishing selectivity and intensity are often constant. Although correlated responses to selection have been hypothesized as potentially important consequences of fishery selection, estimates of quantitative genetic parameters required to predict correlated responses to such selection have been lacking. To my knowledge, my research provides the first estimates of quantitative genetic parameters for larval traits and their links to adult size in a wild population of fish. I used these data to predict how larval size would respond to selection on adults and how evolutionary shifts in larval size would in turn affect population replenishment. My results predict that observed rates of fishery selection on adult marine fishes may decrease average larval size by approximately 0.11 standard deviations after a single generation of selection. Such a reduction in larval size is predicted to reduce survivorship through the larval and early juvenile phases by about 16%. Because the dynamics of many fish populations are highly sensitive to changes in survival of early life stages, the evolution of a higher incidence of low-quality larvae in response to fishery selection may have substantial consequences for the viability of fished populations. Overall, this research indicates that a complex interplay among trait variation, phenotypic selection, and demographic rates may have strong effects on both evolutionary responses and population dynamics. Our understanding of such interactions will be substantially advanced by applying evolutionary quantitative genetics to traditional studies of demography and population dynamics. A combination of these two approaches can yield significant insight into basic evolutionary questions (e.g., why larvae are smaller than expected), as well as applied conservation problems (e.g., predicting correlated responses to fishery selection). Title: Selection on larval and adult body size in a marine fish: potential evolutionary responses and effects on population dynamics Author: Johnson, Darren W. Many species have complex life cycles in which a dispersive larval stage is followed by a relatively sedentary adult stage. For such species, reproductive output is often high and large variation in survivorship throughout early life-history phases (eggs and larvae) can lead to dramatic fluctuations in recruitment which may in turn drive variation in the abundance of juveniles and adults. Early in the life cycle may therefore be a critical period for both natural selection and population dynamics. On one hand, variability in survival during early stages may provide ample opportunity for selection on early life-history traits. On the other hand, phenotypic variation in early life-history traits and selective mortality may be an important source of variability in population dynamics. Variation in survival of marine fish larvae may be a major driver of variability in benthic population size. However, little is known about how variation in larval phenotype may affect larval survival, and less in known about the evolutionary potential of marine fish larvae. I quantified both environmental and genetic sources of variation in larval traits for a field population of a common Atlantic and Caribbean coral-reef fish, the bicolor damselfish (Pomacentridae: Stegastes partitus). I combined field demographic studies and manipulative experiments in the Bahamas to estimate heritability and quantitative genetic parameters for both larval size and swimming performance – two traits that are associated with early survival. I also compiled published estimates of viability selection on larval size from eight species of fish to estimate the average magnitude of selection on this trait. The initial results of these analyses were somewhat paradoxical. Despite ample heritability (h2 = 0.29 for larval size), and strong selection on larval size (mean selection differential = 0.484), the observed mean larval size is quite far from the estimated phenotypic optimum (0.481 standard deviations greater than current mean size), suggesting that marine fish larvae are on average, maladapted with respect to survival during the larval and juvenile phases. Further analyses focused on potential evolutionary constraints on larval size. First, I estimated trade-offs in individual reproductive output between larval quality and quantity. Mothers that produced larger larvae with greater swimming abilities tended to produce fewer larvae, and these effects explained a large component of the mismatch between mean larval size and the phenotypic optimum for survival. Fluctuation in direct selection on larvae may also partially explain why mean larval size is less than optimal. Evolution of larval size may also be strongly influenced by genetic correlations with body size expressed at later ages. I demonstrated substantial additive genetic covariance between adult asymptotic size and both larval size-at-hatching and swimming performance (0.212 and 0.241 on variancestandardized traits, respectively). Adult asymptotic size was also linked to larval traits via size-dependent maternal effects, in which larger mothers provisioned offspring with more yolk resources. Selection on adult body size may therefore cause a substantial correlated genetic response in larval size that may strongly affect the overall evolutionary trajectory of larval traits. I also examined natural selection on body size and growth form in S. partitus. Using data on size, growth and longevity of individual fish studied at 4 sites over a 7-year period, I analyzed both ontogenetic and spatial variation in the magnitude and direction of viability selection on body size. Selection on asymptotic (adult) size was strong and positive at some sites, but weak and negative at other sites. Moreover, fish that were small as juveniles generally experienced greater survival, even if large adult size conferred survival benefits later in life. Both spatial and ontogenetic reversals in selection on body size would be expected to produce similar reversals in the direction of correlated responses of larvae, thereby altering the evolutionary response of larvae and potentially preventing larval size from evolving toward its optimum value. Although this research identified several potential constraints on the evolution of larval traits, there is still considerable scope for an evolutionary response to selection, especially if selection is consistent and strong. Many marine fishes are subject to size-selective fishing where larger, fast-growing individuals are selectively removed from the population. Such effects are usually strong because fishing mortality rates can greatly exceed natural mortality rates and fishing selectivity and intensity are often constant. Although correlated responses to selection have been hypothesized as potentially important consequences of fishery selection, estimates of quantitative genetic parameters required to predict correlated responses to such selection have been lacking. To my knowledge, my research provides the first estimates of quantitative genetic parameters for larval traits and their links to adult size in a wild population of fish. I used these data to predict how larval size would respond to selection on adults and how evolutionary shifts in larval size would in turn affect population replenishment. My results predict that observed rates of fishery selection on adult marine fishes may decrease average larval size by approximately 0.11 standard deviations after a single generation of selection. Such a reduction in larval size is predicted to reduce survivorship through the larval and early juvenile phases by about 16%. Because the dynamics of many fish populations are highly sensitive to changes in survival of early life stages, the evolution of a higher incidence of low-quality larvae in response to fishery selection may have substantial consequences for the viability of fished populations. Overall, this research indicates that a complex interplay among trait variation, phenotypic selection, and demographic rates may have strong effects on both evolutionary responses and population dynamics. Our understanding of such interactions will be substantially advanced by applying evolutionary quantitative genetics to traditional studies of demography and population dynamics. A combination of these two approaches can yield significant insight into basic evolutionary questions (e.g., why larvae are smaller than expected), as well as applied conservation problems (e.g., predicting correlated responses to fishery selection). Close

• 2239. [Article] Science and efficacy of mild sodium hydroxide treatments in enzyme-based wheat straw-to-glucose processing

  The work described in this dissertation focused on chemistry related to the use of aqueous sodium hydroxide as a treatment in the processing of wheat straw. A major emphasis was the comprehensive evaluation ...

  Citation × Citation Citation Abstract Copy Title: Science and efficacy of mild sodium hydroxide treatments in enzyme-based wheat straw-to-glucose processing Author: Sophonputtanaphoca, Supaporn The work described in this dissertation focused on chemistry related to the use of aqueous sodium hydroxide as a treatment in the processing of wheat straw. A major emphasis was the comprehensive evaluation of straw component partitioning due to sodium hydroxide (NaOH) processing. This was evaluated over a range of NaOH concentrations (0­‐10%, w/v), all at 50°C, 5 h treatment period, and 3% solid loading. Solid and liquid phases resulting from NaOH treatments were evaluated. Total solids recovered in the NaOH­‐treated solid phase ranged from 47.4­‐88.0%. Overall carbohydrate recovery in the combined solid and liquid phases was negatively correlated with the alkali concentration of the treatment liquor. The glucan content of the NaOH‐treated solid phase ranged from 37.2­‐67.4%. Glucan recovery in the solid phase was relatively high in all cases, the minimum value being ~98%. Increasing amounts of xylan partitioned into the liquid phase as sodium hydroxide concentrations increased – it ranged from 31­‐83% of the xylan being recovered in the soluble phase. Carbohydrate analyses of the pretreated liquor revealed that the majority of carbohydrate loss from the solid fraction could be recovered in the liquid phase in form of oligomers and monomers due to alkaline degradation. The interconversion of glucose, fructose, and mannose under the alkaline condition played an important role in the presence of those sugars. Increase in NaOH concentration contributed to increase in amount of cellulose­‐derived and hemicellulose‐derived oligomers in the pretreated liquor. All oligomers except fructooligomers in NaOH pretreated liquor were higher than those found in water extraction at 50°C, 5 h. Total carbohydrate recovery from the solid and liquid fractions was as high as 99% for glucose and glucan in 5% NaOH treatment and 80‐95% for xylose and xylan in 1-­10% NaOH treatment. The presence of NaOH as extraction reagent dramatically induced lignin and ash removal from the pretreated solid with up to 63% acid insoluble lignin (AIL) and 87% ash extraction. Solid fractions resulting from NaOH pretreatments (up to 5% NaOH) were tested for their susceptibility to enzymatic saccharification using cellulase and cellulase/xylanase enzyme preparations. The cellulase/xylanase enzyme preparation was found to be more effective at cellulose saccharification than the cellulase enzyme preparation alone. Maximum glucose yield, which corresponded to the 5% NaOH treatment, was 82% over the standard 48 h saccharification period. Extended saccharifications times to 120 h showed that the conversion yield approached 90%. Sequential treatments of the straw (i.e. initial alkali treatment – first enzyme saccharification – second alkali treatment ‐ second enzyme treatment) revealed the NaOH treatment has the potential to render essentially all (~99%) of the straw glucan susceptible to enzyme saccharification. This suggests that the layered molecular arrangement of cellulose, hemicellulose, and lignin in the cell wall impacts biomass recalcitrance and glucan conversion yield. The other major focus of this dissertation research was the characterization of alkali neutralization, which occurs during the aqueous alkali processing of wheat straw. The approach taken was to evaluate the time course of alkali uptake and to determine the underlying nature of alkali uptake. The knowledge generated from this study is useful for understanding the nature of the alkali‐induced chemistry that is at the heart of alkali processing of agricultural byproducts, foods, and forest products. Alkali uptake/acid generation measurements were monitored for wheat straw suspensions at pH 11 and 30°C. The first phase of alkali uptake corresponded to the 30‐second time period over which the pH of the wheat straw suspension was adjusted from its original pH (~6.6) to pH 11. Alkali neutralization during this period was attributed to the instantaneous ionization of solvent accessible Bronstad acids. Following pH adjustment to 11.0, the time course of subsequent alkali uptake was recorded. The time course appeared biphasic. The early phase, which corresponded to the relatively rapid uptake of alkali, was evident during the first 24 hours. The later phase, which was characterized by the relatively slow uptake of alkali, was maintained for the length of the study (up to 96 hours). Alkali uptake during the early phase of the time course appears to be determined by the rate of hydrolysis of readily accessible esters – primarily acetic acid esters (acetyl groups). Alkali uptake during the later phase of the time course appears to be impacted by the rate of alkali penetration into the straw and the rate of production of alkali‐induced acid degradation products. The uptake of alkali in the pH adjustment phase was ~ 120 μEq per gram wheat straw, the uptake of alkali in the early phase of time course was ~ 1,064 μEq per gram wheat straw, and the rate of uptake in the later phase of the time course 6.10 μEq per gram wheat straw per hour. Amount of acetyl groups, ferulic acid, and p-­coumaric acid generated during 96-­h pretreatment revealed that they are major esters being hydrolyzed under the studied condition. Combined, these ester-­derived acids contributed up to ~ 28% of overall alkali uptake. In addition, alkaline degradation products quantified in this study showed additional ~ 28% contribution to the overall alkali uptake. Title: Science and efficacy of mild sodium hydroxide treatments in enzyme-based wheat straw-to-glucose processing Author: Sophonputtanaphoca, Supaporn The work described in this dissertation focused on chemistry related to the use of aqueous sodium hydroxide as a treatment in the processing of wheat straw. A major emphasis was the comprehensive evaluation of straw component partitioning due to sodium hydroxide (NaOH) processing. This was evaluated over a range of NaOH concentrations (0­‐10%, w/v), all at 50°C, 5 h treatment period, and 3% solid loading. Solid and liquid phases resulting from NaOH treatments were evaluated. Total solids recovered in the NaOH­‐treated solid phase ranged from 47.4­‐88.0%. Overall carbohydrate recovery in the combined solid and liquid phases was negatively correlated with the alkali concentration of the treatment liquor. The glucan content of the NaOH‐treated solid phase ranged from 37.2­‐67.4%. Glucan recovery in the solid phase was relatively high in all cases, the minimum value being ~98%. Increasing amounts of xylan partitioned into the liquid phase as sodium hydroxide concentrations increased – it ranged from 31­‐83% of the xylan being recovered in the soluble phase. Carbohydrate analyses of the pretreated liquor revealed that the majority of carbohydrate loss from the solid fraction could be recovered in the liquid phase in form of oligomers and monomers due to alkaline degradation. The interconversion of glucose, fructose, and mannose under the alkaline condition played an important role in the presence of those sugars. Increase in NaOH concentration contributed to increase in amount of cellulose­‐derived and hemicellulose‐derived oligomers in the pretreated liquor. All oligomers except fructooligomers in NaOH pretreated liquor were higher than those found in water extraction at 50°C, 5 h. Total carbohydrate recovery from the solid and liquid fractions was as high as 99% for glucose and glucan in 5% NaOH treatment and 80‐95% for xylose and xylan in 1-­10% NaOH treatment. The presence of NaOH as extraction reagent dramatically induced lignin and ash removal from the pretreated solid with up to 63% acid insoluble lignin (AIL) and 87% ash extraction. Solid fractions resulting from NaOH pretreatments (up to 5% NaOH) were tested for their susceptibility to enzymatic saccharification using cellulase and cellulase/xylanase enzyme preparations. The cellulase/xylanase enzyme preparation was found to be more effective at cellulose saccharification than the cellulase enzyme preparation alone. Maximum glucose yield, which corresponded to the 5% NaOH treatment, was 82% over the standard 48 h saccharification period. Extended saccharifications times to 120 h showed that the conversion yield approached 90%. Sequential treatments of the straw (i.e. initial alkali treatment – first enzyme saccharification – second alkali treatment ‐ second enzyme treatment) revealed the NaOH treatment has the potential to render essentially all (~99%) of the straw glucan susceptible to enzyme saccharification. This suggests that the layered molecular arrangement of cellulose, hemicellulose, and lignin in the cell wall impacts biomass recalcitrance and glucan conversion yield. The other major focus of this dissertation research was the characterization of alkali neutralization, which occurs during the aqueous alkali processing of wheat straw. The approach taken was to evaluate the time course of alkali uptake and to determine the underlying nature of alkali uptake. The knowledge generated from this study is useful for understanding the nature of the alkali‐induced chemistry that is at the heart of alkali processing of agricultural byproducts, foods, and forest products. Alkali uptake/acid generation measurements were monitored for wheat straw suspensions at pH 11 and 30°C. The first phase of alkali uptake corresponded to the 30‐second time period over which the pH of the wheat straw suspension was adjusted from its original pH (~6.6) to pH 11. Alkali neutralization during this period was attributed to the instantaneous ionization of solvent accessible Bronstad acids. Following pH adjustment to 11.0, the time course of subsequent alkali uptake was recorded. The time course appeared biphasic. The early phase, which corresponded to the relatively rapid uptake of alkali, was evident during the first 24 hours. The later phase, which was characterized by the relatively slow uptake of alkali, was maintained for the length of the study (up to 96 hours). Alkali uptake during the early phase of the time course appears to be determined by the rate of hydrolysis of readily accessible esters – primarily acetic acid esters (acetyl groups). Alkali uptake during the later phase of the time course appears to be impacted by the rate of alkali penetration into the straw and the rate of production of alkali‐induced acid degradation products. The uptake of alkali in the pH adjustment phase was ~ 120 μEq per gram wheat straw, the uptake of alkali in the early phase of time course was ~ 1,064 μEq per gram wheat straw, and the rate of uptake in the later phase of the time course 6.10 μEq per gram wheat straw per hour. Amount of acetyl groups, ferulic acid, and p-­coumaric acid generated during 96-­h pretreatment revealed that they are major esters being hydrolyzed under the studied condition. Combined, these ester-­derived acids contributed up to ~ 28% of overall alkali uptake. In addition, alkaline degradation products quantified in this study showed additional ~ 28% contribution to the overall alkali uptake. Close

• 2240. [Article] Flavor chemistry of irradiated milk fat

  Increasing interest has been shown in the irradiation sterilization and irradiation pasteurization of foods, but problems of off-flavors and odors are still unsolved, especially in the case of dairy products. From ...

  Citation × Citation Citation Abstract Copy Title: Flavor chemistry of irradiated milk fat Author: Khatri, Lakho Lilaram Increasing interest has been shown in the irradiation sterilization and irradiation pasteurization of foods, but problems of off-flavors and odors are still unsolved, especially in the case of dairy products. From the flavor chemistry point of view, milk lipids are very highly susceptible to irradiation effects. Therefore, this investigation was designed to study some irradiation induced reactions involving flavor changes in the milk fat and to identify the volatile components produced in the milk fat upon irradiation. Milk fat, prepared from raw sweet cream and washed free of phospholipids, was first irradiated in the presence of air and under vacuum in glass vials at 4.5 Mrad with gamma rays from cobalt-60. The irradiation resulted in increase in TBA number, peroxide value, total monocarbonyls, bleaching of color, slightly rancid and typical candle-like off-flavors. Free fatty acids were also produced upon irradiation. The changes were more drastic in air along with production of a slight oxidized flavor. The monocarbonyls identified by column and paper chromatographic methods in irradiated milk fat include: C₁ through C₁₂, C₁₄ , and C₁₆ n-alkanals; C₃ through C₉, C₁₁, C₁₃ and C₁₅ alk-2-ones with only traces of C₆ and C₈ alk-2- ones; and C₅, C₆, C₉, and C₁₂ alk-2-enals. Irradiation of milk fat that had been dried over calcium hydride also caused free fatty acid production, especially short chain fatty acids. Methyl octanoate treated with calcium hydride and irradiated at 1.5, 3.0, 4.5, and 6.0 Mrad yielded small quantities of free octanoic acid, confirming that irradiation caused fission of the ester linkage even when traces of water were removed. The quantities of octanoic acid formed increased with increasing dose of irradiation. For identification of volatile components, the milk fat was irradiated in 307x409 'C' enameled cans under vacuum. The headspace analysis showed some air still left in the cans. Irradiation resulted in consumption of oxygen and production of hydrogen, carbon monoxide, carbon dioxide, and methane as identified in the headspace gases. The volatiles were isolated from the irradiated and control milk fats by low temperature, vacuum steam distillation at 40°C and 1-2 mm Hg. The volatile components were then extracted from the aqueous distillate with ethyl ether. The ethyl ether extract exhibited the typical candle-like defect. The ethyl ether concentrate was analyzed by combination of GLC and fast-scan mass spectrometric techniques. Identification of various components was achieved on the basis of mass spectral data and coincidence of gas chromatographic retention times. In the case of the components for which only GLC t[subscript r]/t[subscript r] evidence was available or the mass spectra obtained were not satisfactory, the identity assigned was only tentative. The volatile compounds that were positively identified to be present in irradiated milk fat are given below: n-Alkanes C₅ through C₁₇ 1-Alkenes C₅, C₇ through C₁₇ Fatty acids C₄, C₆, C₈ and C₁₀ n-Alkanals C₅ through C₁₁ Others γ-decalactone, δ-decalactone, 2-heptanone, benzene, ethyl acetate, chloroform, and dichlorobenzene. The tentative identification was obtained for the following compounds: γ-lactones C₆ and C₈ δ-lactones C₆, C₈, C₁₁, and C₁₂ 1, ?-alkadienes C₁₀, C₁₁, C₁₂, C₁₆ and C₁₇ iso-alkanes C₁₀, C₁₁, C₁₂, and C₁₃ Others methyl hexanoate, 2-hexanone, 4-heptanone and n-dodecanal. The compounds present in unirradiated control milk fat included: short chain fatty acids (C₄, C₆, C₈, and C₁₀), C₈, C₁₀, and C₁₂ δ-lactones, 2-heptanone, chloroform, dichlorobenzene, benzene, toluene, and ethyl-benzene. Only tentative identity was established for most of these components in control milk fat. Possible reaction mechanisms are presented for the formation of the compounds in irradiated milk fat. Title: Flavor chemistry of irradiated milk fat Author: Khatri, Lakho Lilaram Increasing interest has been shown in the irradiation sterilization and irradiation pasteurization of foods, but problems of off-flavors and odors are still unsolved, especially in the case of dairy products. From the flavor chemistry point of view, milk lipids are very highly susceptible to irradiation effects. Therefore, this investigation was designed to study some irradiation induced reactions involving flavor changes in the milk fat and to identify the volatile components produced in the milk fat upon irradiation. Milk fat, prepared from raw sweet cream and washed free of phospholipids, was first irradiated in the presence of air and under vacuum in glass vials at 4.5 Mrad with gamma rays from cobalt-60. The irradiation resulted in increase in TBA number, peroxide value, total monocarbonyls, bleaching of color, slightly rancid and typical candle-like off-flavors. Free fatty acids were also produced upon irradiation. The changes were more drastic in air along with production of a slight oxidized flavor. The monocarbonyls identified by column and paper chromatographic methods in irradiated milk fat include: C₁ through C₁₂, C₁₄ , and C₁₆ n-alkanals; C₃ through C₉, C₁₁, C₁₃ and C₁₅ alk-2-ones with only traces of C₆ and C₈ alk-2- ones; and C₅, C₆, C₉, and C₁₂ alk-2-enals. Irradiation of milk fat that had been dried over calcium hydride also caused free fatty acid production, especially short chain fatty acids. Methyl octanoate treated with calcium hydride and irradiated at 1.5, 3.0, 4.5, and 6.0 Mrad yielded small quantities of free octanoic acid, confirming that irradiation caused fission of the ester linkage even when traces of water were removed. The quantities of octanoic acid formed increased with increasing dose of irradiation. For identification of volatile components, the milk fat was irradiated in 307x409 'C' enameled cans under vacuum. The headspace analysis showed some air still left in the cans. Irradiation resulted in consumption of oxygen and production of hydrogen, carbon monoxide, carbon dioxide, and methane as identified in the headspace gases. The volatiles were isolated from the irradiated and control milk fats by low temperature, vacuum steam distillation at 40°C and 1-2 mm Hg. The volatile components were then extracted from the aqueous distillate with ethyl ether. The ethyl ether extract exhibited the typical candle-like defect. The ethyl ether concentrate was analyzed by combination of GLC and fast-scan mass spectrometric techniques. Identification of various components was achieved on the basis of mass spectral data and coincidence of gas chromatographic retention times. In the case of the components for which only GLC t[subscript r]/t[subscript r] evidence was available or the mass spectra obtained were not satisfactory, the identity assigned was only tentative. The volatile compounds that were positively identified to be present in irradiated milk fat are given below: n-Alkanes C₅ through C₁₇ 1-Alkenes C₅, C₇ through C₁₇ Fatty acids C₄, C₆, C₈ and C₁₀ n-Alkanals C₅ through C₁₁ Others γ-decalactone, δ-decalactone, 2-heptanone, benzene, ethyl acetate, chloroform, and dichlorobenzene. The tentative identification was obtained for the following compounds: γ-lactones C₆ and C₈ δ-lactones C₆, C₈, C₁₁, and C₁₂ 1, ?-alkadienes C₁₀, C₁₁, C₁₂, C₁₆ and C₁₇ iso-alkanes C₁₀, C₁₁, C₁₂, and C₁₃ Others methyl hexanoate, 2-hexanone, 4-heptanone and n-dodecanal. The compounds present in unirradiated control milk fat included: short chain fatty acids (C₄, C₆, C₈, and C₁₀), C₈, C₁₀, and C₁₂ δ-lactones, 2-heptanone, chloroform, dichlorobenzene, benzene, toluene, and ethyl-benzene. Only tentative identity was established for most of these components in control milk fat. Possible reaction mechanisms are presented for the formation of the compounds in irradiated milk fat. Close