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• 331. [Article] Conserved properties in the metagenome of a large bacterioplankton population

  Candidatus Pelagibacter ubique is the first cultured representative of the SAR11 clade, a clade that is found throughout the oceans and accounts for approximately 25% of all bacterial cells [1]. It has ...

  Citation × Citation Citation Abstract Copy Title: Conserved properties in the metagenome of a large bacterioplankton population Author: Wilhelm, Larry John Candidatus Pelagibacter ubique is the first cultured representative of the SAR11 clade, a clade that is found throughout the oceans and accounts for approximately 25% of all bacterial cells [1]. It has a streamlined genome that is the smallest of any known free-living organism. In this study the complete genome sequence of Candidatus Pelagibacter ubique (strains HTCC1062 and HTCC1002) is used to explore the genomic variability of this organism by taking advantage of the large amount of DNA sequence data collected by Venter et.al. [2] from the Sargasso Sea. Pelagibacter gene homologues in the metagenomic data were identified by tblastn and screened by a reciprocal best blastx test against the NCBI database to identify fragments of probable SAR11 origin. Fragments passing both tests covered 97.8% of the HTCC1062 genome. A subset of fragments spanning two or more SAR11 genes was used to study the conservation of gene order between the Oregon coast isolates and the Sargasso Sea SAR11 population. Boundaries between genes matched the gene order of the HTCC1062 genome in 96% of the cases (> 85,000 observations), although the average amino acid similarity of the genes encoded was only 71%. Alternate gene orders observed in the remaining 3432 fragments indicated that gene rearrangements within the Sargasso Sea population are more likely at boundaries between operons than within operons. Comparisons of the genomes of strains HTCC1062 and HTCC1002, and analysis of the metagenomic data, indicated four regions of genome variability, including a 48 kb cassette between the 23S rRNA gene and the 5S rRNA gene that encodes genes determining cell surface properties. These findings indicate that the temperate gyre population of SAR11 is divergent in nucleotide and amino acid sequence from the coastal isolates, but shares similar gene order and composition in core regions of the genome. The methodology of binning environmental DNA fragments by using sequence similarity and gene-order conservation with known query genomes is validated and shows promise as a general technique to decipher the flood of metagenomic data that is accumulating. Title: Conserved properties in the metagenome of a large bacterioplankton population Author: Wilhelm, Larry John Candidatus Pelagibacter ubique is the first cultured representative of the SAR11 clade, a clade that is found throughout the oceans and accounts for approximately 25% of all bacterial cells [1]. It has a streamlined genome that is the smallest of any known free-living organism. In this study the complete genome sequence of Candidatus Pelagibacter ubique (strains HTCC1062 and HTCC1002) is used to explore the genomic variability of this organism by taking advantage of the large amount of DNA sequence data collected by Venter et.al. [2] from the Sargasso Sea. Pelagibacter gene homologues in the metagenomic data were identified by tblastn and screened by a reciprocal best blastx test against the NCBI database to identify fragments of probable SAR11 origin. Fragments passing both tests covered 97.8% of the HTCC1062 genome. A subset of fragments spanning two or more SAR11 genes was used to study the conservation of gene order between the Oregon coast isolates and the Sargasso Sea SAR11 population. Boundaries between genes matched the gene order of the HTCC1062 genome in 96% of the cases (> 85,000 observations), although the average amino acid similarity of the genes encoded was only 71%. Alternate gene orders observed in the remaining 3432 fragments indicated that gene rearrangements within the Sargasso Sea population are more likely at boundaries between operons than within operons. Comparisons of the genomes of strains HTCC1062 and HTCC1002, and analysis of the metagenomic data, indicated four regions of genome variability, including a 48 kb cassette between the 23S rRNA gene and the 5S rRNA gene that encodes genes determining cell surface properties. These findings indicate that the temperate gyre population of SAR11 is divergent in nucleotide and amino acid sequence from the coastal isolates, but shares similar gene order and composition in core regions of the genome. The methodology of binning environmental DNA fragments by using sequence similarity and gene-order conservation with known query genomes is validated and shows promise as a general technique to decipher the flood of metagenomic data that is accumulating. Close

• 332. [Article] Extension and volcanism : tectonic development of the northwestern margin of the Basin and Range Province in southern Oregon

  The northwestern corner of the Basin and Range Province (NWBR) lies in southeast Oregon where extensive Late Miocene, mafic to bimodal basalt-rhyolite volcanism and extensional faults dominate a stark ...

  Citation × Citation Citation Abstract Copy Title: Extension and volcanism : tectonic development of the northwestern margin of the Basin and Range Province in southern Oregon Author: Scarberry, Kaleb C. The northwestern corner of the Basin and Range Province (NWBR) lies in southeast Oregon where extensive Late Miocene, mafic to bimodal basalt-rhyolite volcanism and extensional faults dominate a stark and arid landscape. Near Lake Abert, the Late Miocene volcanic section abuts Early Miocene, dominantly intermediate composition volcanoes at the Coleman Hills and Rabbit Hills. Such exposures are few in the NWBR and shed light on the volcanic and structural development of the region and significantly extend the known distribution of Early Miocene magmatism. New 40Ar-39Ar ages indicate that magmatism occurred at the Coleman Hills between 21.4 and 22.3 Ma and at the Rabbit Hills between 20.2 and 23.4 Ma. Magmatism at the Coleman Hills initiated with an episode of silicic volcanism that was rapidly followed by the intrusion and emplacement of dacite and andesite dikes and lavas. Early Miocene rhyolite of the Coleman Hills exhibits high 87Sr/86Sri relative to most Late Miocene rocks in the region (0.7051 vs. 0.7037) suggesting that crustal melting was important in their genesis. A notable lack of a Nb-trough, characteristic of subduction zone settings, and high 207Pb/204Pb, and 206Pb/204Pb suggests that these rocks were not generated within a volcanic arc setting and instead likely formed in a back-arc region that had been metasomatized by prior subduction. Crystal fractionation readily accounts for the generation of andesite and dacite compositions from basaltic andesite however a gap in the data between ~66 to 70% SiO2, isotopic variability and disequilibrium textures indicate that crustal anatexis, magma mixing and/or crustal assimilation may also be important processes in the evolutionary history of the Coleman Hills. Dike orientations within Early Miocene volcanoes often mimic the trend of faults that cut Late Miocene volcanic strata, suggesting that the faults may have utilized an existing structural fabric. Contact relations suggest as much as 500 m of volcanic paleo-topography existed near Lake Abert prior to deposition of the Middle Miocene Steens flood basalts at ~16 Ma. Late Miocene structural development of the Abert Rim fault is chronologically linked to the formation and northward propagation of the Walker Lane transform fault system in Nevada between 9 and 3 Ma. At Lake Abert, bimodal basalt-rhyolite volcansim from 8.8 to 7.7 Ma occurred within a zone of active NW-striking faulting. Volcanism during this interval was related to the initiation of faulting at Abert Rim fault. On the basis of morphology and geochemical correlation, Juniper Mountain and Venator Buttes are the source of silicic and mafic volcanism, respectively, between 8.8 to 7.7 Ma. Partial restorations demonstrate that the Abert Rim fault south of 42º40’ N latitude had >250 m of stratigraphic separation prior to deposition of the Rattlesnake Tuff at 7 Ma. The topography north of latitude 42º40’ N was gently sloping at 7 Ma, much like the High Lava Plains are today. Thus, faulting along the NNE-striking Abert Rim initiated between 7.7 and 7 Ma and after the formation of NW-striking fault systems. Title: Extension and volcanism : tectonic development of the northwestern margin of the Basin and Range Province in southern Oregon Author: Scarberry, Kaleb C. The northwestern corner of the Basin and Range Province (NWBR) lies in southeast Oregon where extensive Late Miocene, mafic to bimodal basalt-rhyolite volcanism and extensional faults dominate a stark and arid landscape. Near Lake Abert, the Late Miocene volcanic section abuts Early Miocene, dominantly intermediate composition volcanoes at the Coleman Hills and Rabbit Hills. Such exposures are few in the NWBR and shed light on the volcanic and structural development of the region and significantly extend the known distribution of Early Miocene magmatism. New 40Ar-39Ar ages indicate that magmatism occurred at the Coleman Hills between 21.4 and 22.3 Ma and at the Rabbit Hills between 20.2 and 23.4 Ma. Magmatism at the Coleman Hills initiated with an episode of silicic volcanism that was rapidly followed by the intrusion and emplacement of dacite and andesite dikes and lavas. Early Miocene rhyolite of the Coleman Hills exhibits high 87Sr/86Sri relative to most Late Miocene rocks in the region (0.7051 vs. 0.7037) suggesting that crustal melting was important in their genesis. A notable lack of a Nb-trough, characteristic of subduction zone settings, and high 207Pb/204Pb, and 206Pb/204Pb suggests that these rocks were not generated within a volcanic arc setting and instead likely formed in a back-arc region that had been metasomatized by prior subduction. Crystal fractionation readily accounts for the generation of andesite and dacite compositions from basaltic andesite however a gap in the data between ~66 to 70% SiO2, isotopic variability and disequilibrium textures indicate that crustal anatexis, magma mixing and/or crustal assimilation may also be important processes in the evolutionary history of the Coleman Hills. Dike orientations within Early Miocene volcanoes often mimic the trend of faults that cut Late Miocene volcanic strata, suggesting that the faults may have utilized an existing structural fabric. Contact relations suggest as much as 500 m of volcanic paleo-topography existed near Lake Abert prior to deposition of the Middle Miocene Steens flood basalts at ~16 Ma. Late Miocene structural development of the Abert Rim fault is chronologically linked to the formation and northward propagation of the Walker Lane transform fault system in Nevada between 9 and 3 Ma. At Lake Abert, bimodal basalt-rhyolite volcansim from 8.8 to 7.7 Ma occurred within a zone of active NW-striking faulting. Volcanism during this interval was related to the initiation of faulting at Abert Rim fault. On the basis of morphology and geochemical correlation, Juniper Mountain and Venator Buttes are the source of silicic and mafic volcanism, respectively, between 8.8 to 7.7 Ma. Partial restorations demonstrate that the Abert Rim fault south of 42º40’ N latitude had >250 m of stratigraphic separation prior to deposition of the Rattlesnake Tuff at 7 Ma. The topography north of latitude 42º40’ N was gently sloping at 7 Ma, much like the High Lava Plains are today. Thus, faulting along the NNE-striking Abert Rim initiated between 7.7 and 7 Ma and after the formation of NW-striking fault systems. Close

• 333. [Article] Nowcast/forecast of storm surge and drawdown using a hybrid FE/ANN approach

  In the northwestern Gulf of Mexico there is a need for reliable water level forecasts to facilitate safe commercial navigation, marine construction, and emergency management. Though the low amplitude tides ...

  Citation × Citation Citation Abstract Copy Title: Nowcast/forecast of storm surge and drawdown using a hybrid FE/ANN approach Author: Darnell, Joel T. In the northwestern Gulf of Mexico there is a need for reliable water level forecasts to facilitate safe commercial navigation, marine construction, and emergency management. Though the low amplitude tides of the region can be predicted with conventional harmonic techniques, frequent strong storms make accurate forecasts of water levels difficult. Prediction of surge associated with storms is useful for management of activities in low lying coastal areas subject to flooding, while prediction of drawdown is important for estimating the under keel clearance of deep draft vessels. First, this thesis presents the analysis of nine years of observations to quantify the effects of extra-tropical storms on water level fluctuations at four locations along the northwestern coast of the Gulf of Mexico. The monthly root-mean-square of the meteorological component of the observed water level is shown to be of similar magnitude to the astronomical tide from September to April, attributed to the weekly passage of storm systems. Return periods for extreme maximum (surge) and minimum (drawdown) meteorological water levels associated with these storms are computed using a 9-year record of observed water levels. Significant surge and drawdown water levels, defined as those exceeding 30 cm, are shown to have return periods ranging from 0.17 to 7.14 years at the four stations studied. At the entrance to Galveston Bay, Texas, both significant storm surge and drawdown can be expected to occur about four times each year. These results reinforced the need to include meteorological forcing in the forecasting of water levels in the region. In an effort to provide more accurate water level forecasting within Galveston Bay during storms, the finite element (FE) hydrodynamic model ADCIRC was applied to simulate a range of observed storm events by inclusion of wind stress and remote forcing from the Gulf of Mexico. Comparisons with observations showed the limited accuracy of ADCIRC, as applied here, in predicting the water level response for drawdown events. Thus, the ADCIRC output was incorporated into a data assimilation method utilizing artificial neural networks (ANN). This hybrid FE/ANN approach substantially improved the pure FE simulations for short term forecasts and also outperformed other forecasting methods. With further refinement, this hybrid approach could provide operational forecasts of water levels within Galveston Bay during storms. Title: Nowcast/forecast of storm surge and drawdown using a hybrid FE/ANN approach Author: Darnell, Joel T. In the northwestern Gulf of Mexico there is a need for reliable water level forecasts to facilitate safe commercial navigation, marine construction, and emergency management. Though the low amplitude tides of the region can be predicted with conventional harmonic techniques, frequent strong storms make accurate forecasts of water levels difficult. Prediction of surge associated with storms is useful for management of activities in low lying coastal areas subject to flooding, while prediction of drawdown is important for estimating the under keel clearance of deep draft vessels. First, this thesis presents the analysis of nine years of observations to quantify the effects of extra-tropical storms on water level fluctuations at four locations along the northwestern coast of the Gulf of Mexico. The monthly root-mean-square of the meteorological component of the observed water level is shown to be of similar magnitude to the astronomical tide from September to April, attributed to the weekly passage of storm systems. Return periods for extreme maximum (surge) and minimum (drawdown) meteorological water levels associated with these storms are computed using a 9-year record of observed water levels. Significant surge and drawdown water levels, defined as those exceeding 30 cm, are shown to have return periods ranging from 0.17 to 7.14 years at the four stations studied. At the entrance to Galveston Bay, Texas, both significant storm surge and drawdown can be expected to occur about four times each year. These results reinforced the need to include meteorological forcing in the forecasting of water levels in the region. In an effort to provide more accurate water level forecasting within Galveston Bay during storms, the finite element (FE) hydrodynamic model ADCIRC was applied to simulate a range of observed storm events by inclusion of wind stress and remote forcing from the Gulf of Mexico. Comparisons with observations showed the limited accuracy of ADCIRC, as applied here, in predicting the water level response for drawdown events. Thus, the ADCIRC output was incorporated into a data assimilation method utilizing artificial neural networks (ANN). This hybrid FE/ANN approach substantially improved the pure FE simulations for short term forecasts and also outperformed other forecasting methods. With further refinement, this hybrid approach could provide operational forecasts of water levels within Galveston Bay during storms. Close

• 334. [Article] A model for determining soil contrast and its application to five different soil orders

  A well-defined, quantitative model for determining soil contrast was developed to improve soil survey interpretations concerning the effects of mixtures of different kinds of soils on agricultural land use. ...

  Citation × Citation Citation Abstract Copy Title: A model for determining soil contrast and its application to five different soil orders Author: Villamayor, Faustino Paysan A well-defined, quantitative model for determining soil contrast was developed to improve soil survey interpretations concerning the effects of mixtures of different kinds of soils on agricultural land use. The model was evaluated by determining the levels and reasons for soil contrast on mapped soil areas representing 5 different landscapes, each dominated by a different soil order. Several preliminary models are discussed. The final model is based on twelve soil properties including slope, drainage, depth of rooting, texture and pH. For each property, the range of possible values was divided into a small number of classes. By comparing classes, five levels of contrast (Very Similar, Similar, Somewhat Contrasting, Contrasting, Very Contrasting) were established within each property. These same five terms, plus an additional Exceedingly Contrasting class, were used to characterize the overall degree of contrast between any two soils. Overall contrast was determined by first comparing the property values of a pair of soils and determining the degree of contrast for each property. Then the overall contrast was set equal to either the contrast level for the most contrasting property or properties, or to the next higher contrast level if several properties varied between the two soils. Distributions of contrast levels within soil landscapes show that areas of Inceptisols, Ultisols, Alfisols and Mollisols are characterized by a high percentage of similar soils. The Aridisol landscape sampled had the highest percentage of exceedingly contrasting soils. The Alfisols and Mollisols sampled have the highest percentage of somewhat contrasting and very contrasting soils, respectively. Reasons for soil contrast were determined both by identifying those few properties that actually dictated the contrast level and by calculating a weighted average contribution of each of the 12 soil properties. In general, lower levels of contrast were controlled by one or two properties. At higher levels of contrast, more properties varied, and no property had as dominant an effect. Slope was the major factor controlling the contrast of similar soils. Drainage, pH, texture, and depth of rooting differences, all of which reflected differences in parent materials, were most often expressed at somewhat contrasting or contrasting levels. The most common reason for very contrasting soils was flooding, and that occurred where an alluvial soil was adjacent to an upland soil. Title: A model for determining soil contrast and its application to five different soil orders Author: Villamayor, Faustino Paysan A well-defined, quantitative model for determining soil contrast was developed to improve soil survey interpretations concerning the effects of mixtures of different kinds of soils on agricultural land use. The model was evaluated by determining the levels and reasons for soil contrast on mapped soil areas representing 5 different landscapes, each dominated by a different soil order. Several preliminary models are discussed. The final model is based on twelve soil properties including slope, drainage, depth of rooting, texture and pH. For each property, the range of possible values was divided into a small number of classes. By comparing classes, five levels of contrast (Very Similar, Similar, Somewhat Contrasting, Contrasting, Very Contrasting) were established within each property. These same five terms, plus an additional Exceedingly Contrasting class, were used to characterize the overall degree of contrast between any two soils. Overall contrast was determined by first comparing the property values of a pair of soils and determining the degree of contrast for each property. Then the overall contrast was set equal to either the contrast level for the most contrasting property or properties, or to the next higher contrast level if several properties varied between the two soils. Distributions of contrast levels within soil landscapes show that areas of Inceptisols, Ultisols, Alfisols and Mollisols are characterized by a high percentage of similar soils. The Aridisol landscape sampled had the highest percentage of exceedingly contrasting soils. The Alfisols and Mollisols sampled have the highest percentage of somewhat contrasting and very contrasting soils, respectively. Reasons for soil contrast were determined both by identifying those few properties that actually dictated the contrast level and by calculating a weighted average contribution of each of the 12 soil properties. In general, lower levels of contrast were controlled by one or two properties. At higher levels of contrast, more properties varied, and no property had as dominant an effect. Slope was the major factor controlling the contrast of similar soils. Drainage, pH, texture, and depth of rooting differences, all of which reflected differences in parent materials, were most often expressed at somewhat contrasting or contrasting levels. The most common reason for very contrasting soils was flooding, and that occurred where an alluvial soil was adjacent to an upland soil. Close

• 335. [Article] The migratory pattern of audlt sockeye salmon (Oncorhynchus nerka) in Bristol Bay as related to the distribution of their home-river waters

  The individual stocks of sockeye salmon that make up the annual spawning migration to the Bristol Bay region of Western Alaska are produced in the lakes and streams of ten major river systems, which discharge ...

  Citation × Citation Citation Abstract Copy Title: The migratory pattern of audlt sockeye salmon (Oncorhynchus nerka) in Bristol Bay as related to the distribution of their home-river waters Author: Straty, Richard R. The individual stocks of sockeye salmon that make up the annual spawning migration to the Bristol Bay region of Western Alaska are produced in the lakes and streams of ten major river systems, which discharge into the bay over a shoreline distance of 120 miles. The hypothesis adopted in this study was that the bay distribution of the waters from these river systems and controlling factors such as tide, wind and bottom topography determine the distribution of the individual stocks of sockeye salmon in Bristol Bay. This hypothesis was based on the premise that mature sockeye salmon return to their river system of origin to spawn and in doing so utilize recognizable characteristics of their home-river waters to guide them to its source. Hydrographic studies were carried out in upper Bristol Bay to determine the seaward course and distribution of the waters of major sockeye salmon-producing river systems draining into Bristol Bay. These studies included determination of the vertical and horizontal salinity distribution in the upper bay, tracking and plotting the distribution and course of individual river waters, which had been tagged with Rhodamine B dye, during flood and ebb tide and plotting the seaward course of plastic drift cards released at various strategic locations in upper Bristol Bay. From the results of these studies the course and distribution of the waters of each major sockeye salmon-producing river system was described for upper Bristol Bay. The distribution and migration routes of the individual stocks of Bristol Bay sockeye salmon were determined from analysis of the results of exploratory fishing operations carried out by research vessels of the United States and offshore and inshore adult sockeye salmon tagging studies conducted by the United States and Japan. The results of this analysis showed that the main migration route of all stocks of Bristol Bay sockeye is in the offshore waters of the southern half of the entrance to the bay and in the bay itself. All stocks remain in the offshore waters until within 20 to 50 miles of their home-river systems. They were, however, already beginning, to segregate according to, river of origin in the offshore waters when still as much as 150 miles from the mouths of their home-river systems. From this point to the head of Bristol Bay there was a progressive segregation of sockeye salmon stocks according to their river of origin. From these studies the general distribution and migration route of all major stocks of Bristol Bay sockeye salmon was described and illustrated on a chart of the area. Comparison of the distribution of the major river-system waters with that of their respective sockeye salmon stocks showed that the distribution of river water in outer Bristol Bay did not conform to the distribution of sockeye salmon whereas in the upper bay the individual sockeye stocks assumed a distribution which was very similar to that of their river-system waters. The conclusions reached were that the migration route, distribution and initial segregation of sockeye- stocks in the clear offshore waters of Bristol Bay are not influenced by the distribution of river water, but once in the turbid upper bay these features must somehow be related to the distribution of home-river waters and the recognizable properties they contain. Title: The migratory pattern of audlt sockeye salmon (Oncorhynchus nerka) in Bristol Bay as related to the distribution of their home-river waters Author: Straty, Richard R. The individual stocks of sockeye salmon that make up the annual spawning migration to the Bristol Bay region of Western Alaska are produced in the lakes and streams of ten major river systems, which discharge into the bay over a shoreline distance of 120 miles. The hypothesis adopted in this study was that the bay distribution of the waters from these river systems and controlling factors such as tide, wind and bottom topography determine the distribution of the individual stocks of sockeye salmon in Bristol Bay. This hypothesis was based on the premise that mature sockeye salmon return to their river system of origin to spawn and in doing so utilize recognizable characteristics of their home-river waters to guide them to its source. Hydrographic studies were carried out in upper Bristol Bay to determine the seaward course and distribution of the waters of major sockeye salmon-producing river systems draining into Bristol Bay. These studies included determination of the vertical and horizontal salinity distribution in the upper bay, tracking and plotting the distribution and course of individual river waters, which had been tagged with Rhodamine B dye, during flood and ebb tide and plotting the seaward course of plastic drift cards released at various strategic locations in upper Bristol Bay. From the results of these studies the course and distribution of the waters of each major sockeye salmon-producing river system was described for upper Bristol Bay. The distribution and migration routes of the individual stocks of Bristol Bay sockeye salmon were determined from analysis of the results of exploratory fishing operations carried out by research vessels of the United States and offshore and inshore adult sockeye salmon tagging studies conducted by the United States and Japan. The results of this analysis showed that the main migration route of all stocks of Bristol Bay sockeye is in the offshore waters of the southern half of the entrance to the bay and in the bay itself. All stocks remain in the offshore waters until within 20 to 50 miles of their home-river systems. They were, however, already beginning, to segregate according to, river of origin in the offshore waters when still as much as 150 miles from the mouths of their home-river systems. From this point to the head of Bristol Bay there was a progressive segregation of sockeye salmon stocks according to their river of origin. From these studies the general distribution and migration route of all major stocks of Bristol Bay sockeye salmon was described and illustrated on a chart of the area. Comparison of the distribution of the major river-system waters with that of their respective sockeye salmon stocks showed that the distribution of river water in outer Bristol Bay did not conform to the distribution of sockeye salmon whereas in the upper bay the individual sockeye stocks assumed a distribution which was very similar to that of their river-system waters. The conclusions reached were that the migration route, distribution and initial segregation of sockeye- stocks in the clear offshore waters of Bristol Bay are not influenced by the distribution of river water, but once in the turbid upper bay these features must somehow be related to the distribution of home-river waters and the recognizable properties they contain. Close

• 336. [Article] Chemical control of Elodea densa Planch. and other submersed aquatic plants as influenced by several environmental factors

  Elodea densa Planch. was exposed to diquat (6, 7 dihydrodipyrido [1,2-a: 2', 1'-c] pyrazinediium dibromide), alone and in combination with disodium endothall (disodium salt of 7-oxabicyclo [2.2.1] heptane-2, ...

  Citation × Citation Citation Abstract Copy Title: Chemical control of Elodea densa Planch. and other submersed aquatic plants as influenced by several environmental factors Author: Mackenzie, John William, 1939- Elodea densa Planch. was exposed to diquat (6, 7 dihydrodipyrido [1,2-a: 2', 1'-c] pyrazinediium dibromide), alone and in combination with disodium endothall (disodium salt of 7-oxabicyclo [2.2.1] heptane-2, 3-dicarboxyclic acid), and copper sulfate pentahydrate. Studies were conducted in coastal lakes of Oregon infested with E. densa. Dichlobenil (2, 6 dichlorobenzonitrile) was applied following diquat treatments in an attempt to extend length of the control period. Plant samples were collected from trials in Siltcoos Lake for diquat analysis. Laboratory studies were conducted to determine the effects of water temperature, exposure time, light quality, and time of application on the activity of diquat and diquat combinations against E. densa. Weights of stem, length of stem, and visual control evaluations were used to measure effectiveness of herbicide application. In field trials, effective seasonal control of E. densa was achieved by application of 0.25 ppmw diquat. Addition of 0.25 ppmw endothall or 0.5 ppmw copper sulfate pentahydrate did not enhance the activity of the 0.25 ppmw rate of diquat. The optimum elodea control from 1.0 ppmw diquat did not prevent extensive regrowth the following season. Dichlobenil at 10 and 20 pounds active per acre suppressed but did not completely prevent regrowth in previously diquat-treated plots. Levels of diquat in treated plants were not increased by addition of endothall or copper sulfate. The influence of water movement in Siltcoos Lake from wind and flood water resulted in drift of chemical from treated areas and consequent control of exposed E. densa over significant untreated areas. In the laboratory, preliminary trials demonstrated that submersed plants native to the coastal lakes, Elodea canadensis Michx., Ceratophyllum demersum L., and Myriophyllum verticillatum L. were effectively controlled by 0.25 ppmw diquat as was E. densa. Addition of 0.25 ppmw disodium endothall or 0.5 ppmw copper sulfate pentahydrate did not improve E. densa control with 0.25 ppmw diquat except at 30 C where the diquat-endothall combination was superior. As the water temperature was reduced from 30 C to 20 C to 10 C, expression of the phytotoxicity of diquat was delayed but not prevented. When E. densa was exposed to 0.25 ppmw diquat alone or in combination with 0.25 ppmw endothall, six hours at 30 C and 24 hours at 20 C and 10 C were required for optimum control. At 10 C, the diquatendothall combination and, at 20 and 30 C, the diquat-copper sulfate combination was less effective than 0.25 ppmw diquat alone. When E. densa was grown under the visible light spectrum (360- 740 mμ), the red band (620-740 mμ), the green band (440-620 mμ), and the blue band (360-560 mμ) phytotoxicity of diquat, alone or in combination, was not affected. Application of 0.25 ppmw diquat, alone or in combination with 0.5 ppmw copper sulfate, was most effective for control of E. densa at the beginning or middle of the 12 hour photoperiod rather than at the beginning or middle of the 12 hour dark period. Title: Chemical control of Elodea densa Planch. and other submersed aquatic plants as influenced by several environmental factors Author: Mackenzie, John William, 1939- Elodea densa Planch. was exposed to diquat (6, 7 dihydrodipyrido [1,2-a: 2', 1'-c] pyrazinediium dibromide), alone and in combination with disodium endothall (disodium salt of 7-oxabicyclo [2.2.1] heptane-2, 3-dicarboxyclic acid), and copper sulfate pentahydrate. Studies were conducted in coastal lakes of Oregon infested with E. densa. Dichlobenil (2, 6 dichlorobenzonitrile) was applied following diquat treatments in an attempt to extend length of the control period. Plant samples were collected from trials in Siltcoos Lake for diquat analysis. Laboratory studies were conducted to determine the effects of water temperature, exposure time, light quality, and time of application on the activity of diquat and diquat combinations against E. densa. Weights of stem, length of stem, and visual control evaluations were used to measure effectiveness of herbicide application. In field trials, effective seasonal control of E. densa was achieved by application of 0.25 ppmw diquat. Addition of 0.25 ppmw endothall or 0.5 ppmw copper sulfate pentahydrate did not enhance the activity of the 0.25 ppmw rate of diquat. The optimum elodea control from 1.0 ppmw diquat did not prevent extensive regrowth the following season. Dichlobenil at 10 and 20 pounds active per acre suppressed but did not completely prevent regrowth in previously diquat-treated plots. Levels of diquat in treated plants were not increased by addition of endothall or copper sulfate. The influence of water movement in Siltcoos Lake from wind and flood water resulted in drift of chemical from treated areas and consequent control of exposed E. densa over significant untreated areas. In the laboratory, preliminary trials demonstrated that submersed plants native to the coastal lakes, Elodea canadensis Michx., Ceratophyllum demersum L., and Myriophyllum verticillatum L. were effectively controlled by 0.25 ppmw diquat as was E. densa. Addition of 0.25 ppmw disodium endothall or 0.5 ppmw copper sulfate pentahydrate did not improve E. densa control with 0.25 ppmw diquat except at 30 C where the diquat-endothall combination was superior. As the water temperature was reduced from 30 C to 20 C to 10 C, expression of the phytotoxicity of diquat was delayed but not prevented. When E. densa was exposed to 0.25 ppmw diquat alone or in combination with 0.25 ppmw endothall, six hours at 30 C and 24 hours at 20 C and 10 C were required for optimum control. At 10 C, the diquatendothall combination and, at 20 and 30 C, the diquat-copper sulfate combination was less effective than 0.25 ppmw diquat alone. When E. densa was grown under the visible light spectrum (360- 740 mμ), the red band (620-740 mμ), the green band (440-620 mμ), and the blue band (360-560 mμ) phytotoxicity of diquat, alone or in combination, was not affected. Application of 0.25 ppmw diquat, alone or in combination with 0.5 ppmw copper sulfate, was most effective for control of E. densa at the beginning or middle of the 12 hour photoperiod rather than at the beginning or middle of the 12 hour dark period. Close

• 337. [Article] A Collaborative Effort to Evaluate Water Resources in the Lower Siuslaw Watershed

  Presented at The Oregon Water Conference, May 24-25, 2011, Corvallis, OR.

  Citation × Citation Citation Abstract Copy Title: A Collaborative Effort to Evaluate Water Resources in the Lower Siuslaw Watershed Author: Livesay, Dave, Miller, Mike, Nelson, Dennis, Moellendorf, Suzanne Year: 2011 Presented at The Oregon Water Conference, May 24-25, 2011, Corvallis, OR. Title: A Collaborative Effort to Evaluate Water Resources in the Lower Siuslaw Watershed Author: Livesay, Dave, Miller, Mike, Nelson, Dennis, Moellendorf, Suzanne Year: 2011 Presented at The Oregon Water Conference, May 24-25, 2011, Corvallis, OR. Close

• 338. [Article] Waning magmatic activity along the Southern Explorer Ridge revealed through fault restoration of rift topography

  To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. American Geophysical Union – Geochemistry, Geophysics, Geosystems - G³ This is the ...

  Citation × Citation Citation Abstract Copy Title: Waning magmatic activity along the Southern Explorer Ridge revealed through fault restoration of rift topography Author: Chadwick Jr., W. W., Tivey, M. A., Deschamps, A., Embley, R. W. To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. American Geophysical Union – Geochemistry, Geophysics, Geosystems - G³ This is the publisher’s final pdf. The published article is copyrighted by the American Geophysical Union and can be found at: http://www.agu.org/journals/gc/. Title: Waning magmatic activity along the Southern Explorer Ridge revealed through fault restoration of rift topography Author: Chadwick Jr., W. W., Tivey, M. A., Deschamps, A., Embley, R. W. To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. American Geophysical Union – Geochemistry, Geophysics, Geosystems - G³ This is the publisher’s final pdf. The published article is copyrighted by the American Geophysical Union and can be found at: http://www.agu.org/journals/gc/. Close

• 339. [Article] Modeling Large Wood Impacts on Stream Hydrodynamics and Juvenile Salmon Habitat

  Large wood (LW) pieces are recognized as an important habitat component for salmon freshwater habitat. As such, they are often used in stream habitat restoration practices despite a lack of knowledge about ...

  Citation × Citation Citation Abstract Copy Title: Modeling Large Wood Impacts on Stream Hydrodynamics and Juvenile Salmon Habitat Author: Bair, Russell Large wood (LW) pieces are recognized as an important habitat component for salmon freshwater habitat. As such, they are often used in stream habitat restoration practices despite a lack of knowledge about their impacts on spatial and temporal hydraulic characteristics relevant to fish habitat. In this thesis we present results on the impacts of LW on reach scale stream hydraulics. We use hydraulic models to identifying patterns and magnitudes of change in aspects of the flow field that are relevant to juvenile Coho Salmon after an addition of LW. The Nays2DH model was used because of its capacity to model unsteady flows around LW structures in-stream. Flow conditions after LW addition were modeled in three alluvial plane bed gravel reaches of Mill Creek in the Oregon Coast Range, a long term salmon life cycle study site. Study streams are small, with a bankfull (Q[subscript bf]) discharge between 2.2 and 8.7 m³/s and bankfull widths varying from 5.5 to 10.6 m. Survivable habitat was characterized for the flow field in terms of a) velocity (v) less than critical swim speed of juvenile Coho Salmon (v[subscript crit] = 0.5 m/s); b) and bed refuge estimated based on the likelihood of the movement of the reach median bed particle size (D₅₀). Spatial and temporal increases in wetted area were also determined. After the addition of LW, the area of acceptable habitat increased 17-26% in terms of velocity, 31-39% in terms of substrate stability, and 24-35% in terms of wetted area at Q[subscript bf]. Similar magnitudes of increase were observed over an entire storm hydrograph in each site. Patterns of change in the flow field showed deep pools of slower water forming upstream of LW jams which agreed with initial field observations of geomorphic change. Newly inundated flood plains and bars represented large portions of the additional habitat after the addition of LW. These areas had low velocity and shear stress values indicating that their contributions to additional habitat will be resilient to fluctuation even if acceptable habitat metrics were to be adjusted. Title: Modeling Large Wood Impacts on Stream Hydrodynamics and Juvenile Salmon Habitat Author: Bair, Russell Large wood (LW) pieces are recognized as an important habitat component for salmon freshwater habitat. As such, they are often used in stream habitat restoration practices despite a lack of knowledge about their impacts on spatial and temporal hydraulic characteristics relevant to fish habitat. In this thesis we present results on the impacts of LW on reach scale stream hydraulics. We use hydraulic models to identifying patterns and magnitudes of change in aspects of the flow field that are relevant to juvenile Coho Salmon after an addition of LW. The Nays2DH model was used because of its capacity to model unsteady flows around LW structures in-stream. Flow conditions after LW addition were modeled in three alluvial plane bed gravel reaches of Mill Creek in the Oregon Coast Range, a long term salmon life cycle study site. Study streams are small, with a bankfull (Q[subscript bf]) discharge between 2.2 and 8.7 m³/s and bankfull widths varying from 5.5 to 10.6 m. Survivable habitat was characterized for the flow field in terms of a) velocity (v) less than critical swim speed of juvenile Coho Salmon (v[subscript crit] = 0.5 m/s); b) and bed refuge estimated based on the likelihood of the movement of the reach median bed particle size (D₅₀). Spatial and temporal increases in wetted area were also determined. After the addition of LW, the area of acceptable habitat increased 17-26% in terms of velocity, 31-39% in terms of substrate stability, and 24-35% in terms of wetted area at Q[subscript bf]. Similar magnitudes of increase were observed over an entire storm hydrograph in each site. Patterns of change in the flow field showed deep pools of slower water forming upstream of LW jams which agreed with initial field observations of geomorphic change. Newly inundated flood plains and bars represented large portions of the additional habitat after the addition of LW. These areas had low velocity and shear stress values indicating that their contributions to additional habitat will be resilient to fluctuation even if acceptable habitat metrics were to be adjusted. Close

• 340. [Article] Structure of the crust beneath Lake Superior from forward modeling of large aperture seismic data

  Both travel times and amplitudes of large offset refracted and reflected arrivals observed during GLIMPCE (Great Lakes International Multidisciplinary Program on Crustal Evolution) along line A in Lake ...

  Citation × Citation Citation Abstract Copy Title: Structure of the crust beneath Lake Superior from forward modeling of large aperture seismic data Author: Shay, John T. Both travel times and amplitudes of large offset refracted and reflected arrivals observed during GLIMPCE (Great Lakes International Multidisciplinary Program on Crustal Evolution) along line A in Lake Superior have been modeled using two-dimensional ray tracing techniques. Forward modeling was used to iteratively refine an initial velocity model that was constructed from results of tau-sum analysis of the travel time data at each station combined with information from the coincident common depth point (CDP) reflection profile. When converted to time the resulting model agrees quite well with the CDP reflection profile. A 50-100 ms time advance anomaly associated with the Isle Royal Fault is observed at every station. This anomaly has been modeled as shallow, high velocity blocks located directly beneath the fault. The blocks correlate well with the walls of a steep-sided bathymetric trough and are believed to represent highly indurated upper Keweenawan sediments which may have resulted from hydrothermal alteration. Approximately 2 km of sedimentary rock (2.8-4.6 km/sec) overlie an 8 km thick sequence of volcanics and interflow sediments (5.0-6.5 km/sec) within the rift graben observed on the reflection data. Beneath this sequence is a 6-8 km thick sequence of 6.6-7.0 km/sec material that is interpreted to represent metamorphosed volcanics. The velocity of the material at the base of the rift graben is not well constrained (approximately 7.0 -7.2 km/sec), but probably comprises an additional 10-12 kilometers of meta-volcanic rocks and intrusions that extend to the base of the graben as imaged on the CDP reflection profile. Boundaries between these sequences are indicated by reflections observed at several of the wide-aperture stations. A marked decrease in the apparent velocity and amplitude of the first arrivals is observed on reversed sections at ranges exceeding 100 km. This decrease in apparent velocity has been modeled as lower velocity continental crustal rocks (approximately 6.5 km/sec) at a depth of about 15-20 km adjacent to the 7.0 km/sec material in the graben. Calculation of the gravity response of the seismic model demonstrates that the gravity high centered over the rift can be entirely attributed to high density rocks occupying the central half-graben imaged on the CDP profile. Wide angle reflections from about 15-30 km depth beneath the flanks of the graben indicate the presence of velocity discontinuities that may represent rift related detachment surfaces and/or pre-rift structures. Modeling of wide angle reflections indicate a high degree of structural relief preserved within the lower crust. The high velocities modeled for this region, coupled with information from the CDP profile, suggest that the lower crust represents Archean crust that has been either heavily intruded or underplated by mafic magma. The style and volume of volcanic emplacement is similar to that of Phanerozoic rifted continental margins and flood basalt provinces. By analogy, the volcanism within the midcontinent rift appears to have resulted from decompression melting during lithospheric extension above a broad, asthenospheric thermal anomaly recently referred to in the literature as the "Keweenawan hot spot". Title: Structure of the crust beneath Lake Superior from forward modeling of large aperture seismic data Author: Shay, John T. Both travel times and amplitudes of large offset refracted and reflected arrivals observed during GLIMPCE (Great Lakes International Multidisciplinary Program on Crustal Evolution) along line A in Lake Superior have been modeled using two-dimensional ray tracing techniques. Forward modeling was used to iteratively refine an initial velocity model that was constructed from results of tau-sum analysis of the travel time data at each station combined with information from the coincident common depth point (CDP) reflection profile. When converted to time the resulting model agrees quite well with the CDP reflection profile. A 50-100 ms time advance anomaly associated with the Isle Royal Fault is observed at every station. This anomaly has been modeled as shallow, high velocity blocks located directly beneath the fault. The blocks correlate well with the walls of a steep-sided bathymetric trough and are believed to represent highly indurated upper Keweenawan sediments which may have resulted from hydrothermal alteration. Approximately 2 km of sedimentary rock (2.8-4.6 km/sec) overlie an 8 km thick sequence of volcanics and interflow sediments (5.0-6.5 km/sec) within the rift graben observed on the reflection data. Beneath this sequence is a 6-8 km thick sequence of 6.6-7.0 km/sec material that is interpreted to represent metamorphosed volcanics. The velocity of the material at the base of the rift graben is not well constrained (approximately 7.0 -7.2 km/sec), but probably comprises an additional 10-12 kilometers of meta-volcanic rocks and intrusions that extend to the base of the graben as imaged on the CDP reflection profile. Boundaries between these sequences are indicated by reflections observed at several of the wide-aperture stations. A marked decrease in the apparent velocity and amplitude of the first arrivals is observed on reversed sections at ranges exceeding 100 km. This decrease in apparent velocity has been modeled as lower velocity continental crustal rocks (approximately 6.5 km/sec) at a depth of about 15-20 km adjacent to the 7.0 km/sec material in the graben. Calculation of the gravity response of the seismic model demonstrates that the gravity high centered over the rift can be entirely attributed to high density rocks occupying the central half-graben imaged on the CDP profile. Wide angle reflections from about 15-30 km depth beneath the flanks of the graben indicate the presence of velocity discontinuities that may represent rift related detachment surfaces and/or pre-rift structures. Modeling of wide angle reflections indicate a high degree of structural relief preserved within the lower crust. The high velocities modeled for this region, coupled with information from the CDP profile, suggest that the lower crust represents Archean crust that has been either heavily intruded or underplated by mafic magma. The style and volume of volcanic emplacement is similar to that of Phanerozoic rifted continental margins and flood basalt provinces. By analogy, the volcanism within the midcontinent rift appears to have resulted from decompression melting during lithospheric extension above a broad, asthenospheric thermal anomaly recently referred to in the literature as the "Keweenawan hot spot". Close