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• 71. [Article] The influence of environmental and physical factors on the thermal patterns of headwater streams

  A case study was performed in 2000 and 2001 to characterize the thermal pattern of four morphologically similar eastern Oregon streams and to identify the physical and environmental factors that expressed ...

  Citation × Citation Citation Abstract Copy Title: The influence of environmental and physical factors on the thermal patterns of headwater streams Author: Carr, Craig A. A case study was performed in 2000 and 2001 to characterize the thermal pattern of four morphologically similar eastern Oregon streams and to identify the physical and environmental factors that expressed significant and functionally viable relationships with stream temperature (daily maximum, daily minimum and daily rate of heating). Stream and environmental attributes were measured at various locations along each stream to provide a data set comprised of variables representing daily stream temperatures (minimum, maximum and rates of heating), daily air temperatures (minimum and maximum), shade, elevation, elevation change and length. Data from the 20 hottest days were analyzed using analysis of variance and regression-based path analysis. With the exception of those reaches that were influenced by groundwater or subsurface flow, downstream reaches consistently experienced increases in the daily maximum stream temperature. The most significant parameter with respect to daily maximum stream temperature appeared to be reach elevation; expressed through reach location in the watershed. Maximum air temperature also positively influenced maximum stream temperature however, only on streams that expressed significant variation in maximum air temperature. The dominant influence of groundwater on maximum stream temperature was also apparent. Significant reach level variation in daily minimum stream temperatures was not observed in this study, however most streams did record increases in the downstream direction. Daily minimum air temperature was consistent across all streams in expressing the most significant relationship with daily minimum stream temperature. With the exception of groundwater influenced reaches, all streams exhibited obvious downstream increases in the daily rate of stream heating. Daily minimum air temperature consistently exhibited a significant negative association with the rate of heating and a relationship was also implied between reach elevation, maximum stream temperature and minimum stream temperature and this stream temperature response. Groundwater and subsurface flow, when present, also appeared to influence the daily rate of stream heating. Resource management activities should have little impact on the parameters found, on these streams, to be associated with stream temperature. Location in the watershed and climatic influence through both minimum and maximum air temperatures emerged as the dominant factors with respect to stream thermal patterns. Title: The influence of environmental and physical factors on the thermal patterns of headwater streams Author: Carr, Craig A. A case study was performed in 2000 and 2001 to characterize the thermal pattern of four morphologically similar eastern Oregon streams and to identify the physical and environmental factors that expressed significant and functionally viable relationships with stream temperature (daily maximum, daily minimum and daily rate of heating). Stream and environmental attributes were measured at various locations along each stream to provide a data set comprised of variables representing daily stream temperatures (minimum, maximum and rates of heating), daily air temperatures (minimum and maximum), shade, elevation, elevation change and length. Data from the 20 hottest days were analyzed using analysis of variance and regression-based path analysis. With the exception of those reaches that were influenced by groundwater or subsurface flow, downstream reaches consistently experienced increases in the daily maximum stream temperature. The most significant parameter with respect to daily maximum stream temperature appeared to be reach elevation; expressed through reach location in the watershed. Maximum air temperature also positively influenced maximum stream temperature however, only on streams that expressed significant variation in maximum air temperature. The dominant influence of groundwater on maximum stream temperature was also apparent. Significant reach level variation in daily minimum stream temperatures was not observed in this study, however most streams did record increases in the downstream direction. Daily minimum air temperature was consistent across all streams in expressing the most significant relationship with daily minimum stream temperature. With the exception of groundwater influenced reaches, all streams exhibited obvious downstream increases in the daily rate of stream heating. Daily minimum air temperature consistently exhibited a significant negative association with the rate of heating and a relationship was also implied between reach elevation, maximum stream temperature and minimum stream temperature and this stream temperature response. Groundwater and subsurface flow, when present, also appeared to influence the daily rate of stream heating. Resource management activities should have little impact on the parameters found, on these streams, to be associated with stream temperature. Location in the watershed and climatic influence through both minimum and maximum air temperatures emerged as the dominant factors with respect to stream thermal patterns. Close

• 72. [Article] The influence of contemporary forest harvesting on summer stream temperatures in headwater streams of Hinkle Creek, Oregon

  Stream temperature is a water quality parameter that directly influences the quality of aquatic habitat, particularly for cold-water species such as Pacific salmonids. Forest harvesting adjacent to a stream ...

  Citation × Citation Citation Abstract Copy Title: The influence of contemporary forest harvesting on summer stream temperatures in headwater streams of Hinkle Creek, Oregon Author: Kibler, Kelly Maren Stream temperature is a water quality parameter that directly influences the quality of aquatic habitat, particularly for cold-water species such as Pacific salmonids. Forest harvesting adjacent to a stream can increase the amount of solar radiation the stream receives, which can elevate stream temperatures and impair aquatic habitat. Oregon Forest Practice Rules mandate that forest operators leave Riparian Management Areas (RMAs) adjacent to streams in order to minimize the water quality impacts from forest harvesting. However, RMAs that contain overstory merchantable conifers are not required for small non-fish-bearing streams in Oregon, thus there is potential for increases in stream temperature to occur in headwater streams after harvesting. There is concern that increases in stream temperatures and changes to onsite processes in non-fish-bearing, headwater streams may propagate downstream and impair habitat in fish-bearing streams. The objectives of the following work are to assess the effects of contemporary forest management practices on stream temperatures of small non-fish-bearing headwater streams and to develop new knowledge regarding the physical processes that control reach-level stream temperature patterns. Summer stream temperatures were measured for five years in six headwater streams in the Hinkle Creek basin in southern Oregon. After four years, four of the streams were harvested and vegetated RMAs were not left between the streams and harvest units. The watersheds of the two remaining streams were not disturbed. Post-harvest stream temperatures were monitored for one year in all six streams. Each harvested stream was paired with one unharvested stream and regression relationships for maximum, minimum and mean daily stream temperatures were developed. Changes to temperatures of harvested streams were detected by comparing the mean pre-harvest regression relationship to the mean post-harvest relationship. Change detection analyses that considered the mean response among all four harvested streams indicated that maximum daily stream temperatures did not increase after harvesting, but that minimum and mean daily temperatures decreased significantly after harvesting. Additionally, diel stream temperature fluctuations were significantly greater one year after harvesting. Pre- and post-harvest surveys of canopy closure in the harvested and unharvested streams were completed in order to compare levels of stream shading before and after harvest. The post-harvest survey quantified canopy closure from remaining overstory vegetation as well as from logging slash that partially covered the harvested streams. The surveys indicated that mean overstory canopy closure in the harvested streams decreased by 84% as a result of the harvest, but as the logging slash provided considerable cover, total canopy closure decreased by only 20%. It is possible that the logging slash effectively attenuated solar radiation and prevented extreme temperature increases in the harvested streams. However, it is likely that streamflow increased after harvesting and that the increased streamflow also prevented increases to maximum temperatures and contributed to lower minimum and mean stream temperatures. Title: The influence of contemporary forest harvesting on summer stream temperatures in headwater streams of Hinkle Creek, Oregon Author: Kibler, Kelly Maren Stream temperature is a water quality parameter that directly influences the quality of aquatic habitat, particularly for cold-water species such as Pacific salmonids. Forest harvesting adjacent to a stream can increase the amount of solar radiation the stream receives, which can elevate stream temperatures and impair aquatic habitat. Oregon Forest Practice Rules mandate that forest operators leave Riparian Management Areas (RMAs) adjacent to streams in order to minimize the water quality impacts from forest harvesting. However, RMAs that contain overstory merchantable conifers are not required for small non-fish-bearing streams in Oregon, thus there is potential for increases in stream temperature to occur in headwater streams after harvesting. There is concern that increases in stream temperatures and changes to onsite processes in non-fish-bearing, headwater streams may propagate downstream and impair habitat in fish-bearing streams. The objectives of the following work are to assess the effects of contemporary forest management practices on stream temperatures of small non-fish-bearing headwater streams and to develop new knowledge regarding the physical processes that control reach-level stream temperature patterns. Summer stream temperatures were measured for five years in six headwater streams in the Hinkle Creek basin in southern Oregon. After four years, four of the streams were harvested and vegetated RMAs were not left between the streams and harvest units. The watersheds of the two remaining streams were not disturbed. Post-harvest stream temperatures were monitored for one year in all six streams. Each harvested stream was paired with one unharvested stream and regression relationships for maximum, minimum and mean daily stream temperatures were developed. Changes to temperatures of harvested streams were detected by comparing the mean pre-harvest regression relationship to the mean post-harvest relationship. Change detection analyses that considered the mean response among all four harvested streams indicated that maximum daily stream temperatures did not increase after harvesting, but that minimum and mean daily temperatures decreased significantly after harvesting. Additionally, diel stream temperature fluctuations were significantly greater one year after harvesting. Pre- and post-harvest surveys of canopy closure in the harvested and unharvested streams were completed in order to compare levels of stream shading before and after harvest. The post-harvest survey quantified canopy closure from remaining overstory vegetation as well as from logging slash that partially covered the harvested streams. The surveys indicated that mean overstory canopy closure in the harvested streams decreased by 84% as a result of the harvest, but as the logging slash provided considerable cover, total canopy closure decreased by only 20%. It is possible that the logging slash effectively attenuated solar radiation and prevented extreme temperature increases in the harvested streams. However, it is likely that streamflow increased after harvesting and that the increased streamflow also prevented increases to maximum temperatures and contributed to lower minimum and mean stream temperatures. Close

• 73. [Article] Soil organic carbon response to six years of warming : assessing the impacts of altered diurnal temperature range

  There is a growing consensus that anthropogenic warming will impact soil organic matter (SOM). Globally, soil contains 2-3 times more carbon (C) than plants, and like plants, temperature induced change ...

  Citation × Citation Citation Abstract Copy Title: Soil organic carbon response to six years of warming : assessing the impacts of altered diurnal temperature range Author: Murphey, Virginia L. W. There is a growing consensus that anthropogenic warming will impact soil organic matter (SOM). Globally, soil contains 2-3 times more carbon (C) than plants, and like plants, temperature induced change of SOM could have significant climate repercussions. Although, the majority of warming experiments have increased day and night temperatures equally, there is evidence of greater increase in global minimum temperatures compared to midday maxima, resulting in an altered mean diurnal temperature range (DTR). Here, intact grassland mesocosms (Terracosm facility, Corvallis OR) were used to assess soil organic C (SOC) changes resulting from altered DTR over a six year period. We assessed the response of SOC to a mean temperature increase of 3.5°C with three temperature treatments: symmetric (SYM) warming of +3.5°C, asymmetric (ASYM) warming of +5°C/ +2°C at minimum and maximum daily temperature, respectively, and control treatments that were kept at ambient (AMB) temperatures. After six years of warming SOC was surprisingly unaltered by increased temperature and was more strongly influenced by plant dynamics than expected. The strongest temperature response was from soil respiration (reported as In-situ cumulative soil C mineralization) with at least 33% higher cumulative C mineralization in warming treatments. In agreement with the soil respiration response, light fraction C (<1.8g/cm³) was depleted in warming treatments (8-10% less C than AMB) at shallow depths. However, laboratory cumulative soil C mineralization, a measure of most easily degraded SOC, had a lack of response to temperature, and actually had trends for greater C in warming treatments. This response was further validated by increased soil water dissolved organic C (DOC) concentration in warming treatments. An increase in these measures suggested that plants were more influential than temperature for highly labile SOC. Aggregates, an important part of SOC allocation and sequestration, had a differential response to SYM and ASYM treatments but this was likely more directly caused by root dynamics than temperature treatment. Due to varying responses of SOC indicators, C budgets were used to assess total ecosystem C balance. We found that under AMB conditions soil was an atmospheric C sink and under both SYM and ASYM conditions soil was an atmospheric C source, with ASYM having a higher source potential than SYM. Overall, SOC responded to both temperature increase via soil respiration and differentially to temperature treatments based on plant response. We expect that a reduced diurnal temperature range could affect soil C differently than mean temperature increase, if plant differences are sustained. Title: Soil organic carbon response to six years of warming : assessing the impacts of altered diurnal temperature range Author: Murphey, Virginia L. W. There is a growing consensus that anthropogenic warming will impact soil organic matter (SOM). Globally, soil contains 2-3 times more carbon (C) than plants, and like plants, temperature induced change of SOM could have significant climate repercussions. Although, the majority of warming experiments have increased day and night temperatures equally, there is evidence of greater increase in global minimum temperatures compared to midday maxima, resulting in an altered mean diurnal temperature range (DTR). Here, intact grassland mesocosms (Terracosm facility, Corvallis OR) were used to assess soil organic C (SOC) changes resulting from altered DTR over a six year period. We assessed the response of SOC to a mean temperature increase of 3.5°C with three temperature treatments: symmetric (SYM) warming of +3.5°C, asymmetric (ASYM) warming of +5°C/ +2°C at minimum and maximum daily temperature, respectively, and control treatments that were kept at ambient (AMB) temperatures. After six years of warming SOC was surprisingly unaltered by increased temperature and was more strongly influenced by plant dynamics than expected. The strongest temperature response was from soil respiration (reported as In-situ cumulative soil C mineralization) with at least 33% higher cumulative C mineralization in warming treatments. In agreement with the soil respiration response, light fraction C (<1.8g/cm³) was depleted in warming treatments (8-10% less C than AMB) at shallow depths. However, laboratory cumulative soil C mineralization, a measure of most easily degraded SOC, had a lack of response to temperature, and actually had trends for greater C in warming treatments. This response was further validated by increased soil water dissolved organic C (DOC) concentration in warming treatments. An increase in these measures suggested that plants were more influential than temperature for highly labile SOC. Aggregates, an important part of SOC allocation and sequestration, had a differential response to SYM and ASYM treatments but this was likely more directly caused by root dynamics than temperature treatment. Due to varying responses of SOC indicators, C budgets were used to assess total ecosystem C balance. We found that under AMB conditions soil was an atmospheric C sink and under both SYM and ASYM conditions soil was an atmospheric C source, with ASYM having a higher source potential than SYM. Overall, SOC responded to both temperature increase via soil respiration and differentially to temperature treatments based on plant response. We expect that a reduced diurnal temperature range could affect soil C differently than mean temperature increase, if plant differences are sustained. Close

• 74. [Article] Temperature and the bioenergetics of Cichlasoma bimaculatum

  One means of evaluating the temperature requirements of an animal is to determine changes temperature causes in the uses and losses of energy and materials in the food the animal consumes. To develop energy ...

  Citation × Citation Citation Abstract Copy Title: Temperature and the bioenergetics of Cichlasoma bimaculatum Author: Sethi, Hari Singh One means of evaluating the temperature requirements of an animal is to determine changes temperature causes in the uses and losses of energy and materials in the food the animal consumes. To develop energy budgets for cichlids (Cichlasoma bimaculatum) at different temperatures (20, 24, 28, 32 and 36 C) data were obtained on food intake, growth (total, fat, and protein), fecal losses, maintenance requirements, and other uses and losses of energy and materials including specific dynamic action, activity, and nitrogen excretion. Starvation experiments were conducted to provide information on the metabolic cost of existence and on adjustments in body composition in the absence of food. Energy expenditure during starvation, estimated from heat of combustion data, was found to increase linearly with temperature over 4, 13 and 20 days of starvation. The caloric cost of existence per fish per day was greatest during the first four days at all temperatures and decreased as starvation was prolonged to 20 days. Caloric losses, and dry weight losses showed essentially the same thing. Protein catabolism increased regularly with temperature and decreased slightly with duration of starvation. Fat catabolism did not vary significantly with temperature but decreased markedly as starvation was prolonged. Food intake, growth, and food conversion efficiency varied greatly with changes in temperature. Cichlids were fed ad libitum on small aquatic worms of the genus Tubifex. For food consumption as well as growth, the optimum temperature dropped from 32 to 28 to 24 C as the experimental period was extended from 5 to 12 to 19 days. Optimum growth in dry weight and calories occurred at the same temperatures. Growth of cichlids through time at 20 and 28 C was nearly linear; at 24 C the curve was exponential. At 32 and 36 C, the growth curves rose and then declined. When the fish were held separately during the experiment, food conversion efficiency of cichlids was highest at 20 C and decreased with increasing temperature. Efficiencies decreased with duration of the experiment. When fish were held in groups during the experiment, efficiency was low at both high and low temperatures. The guts of the cichlids were found to contain food up to 30 hours after an ad libitum meal at all temperatures. They were reasonably empty after 36 hours. Thus, no significant correlation was found between temperature and the length of time necessary for the guts to empty. Food material not absorbed was measured by wet combustion. Percentages of absorption of unrestricted rations were found to be 83, 84, 88, 85 and 69 at 20, 24, 28, 32 and 36 C. Percentages of food absorption were much higher on the restricted ration than on the unrestricted ration. Absorption appears to have been optimal at 28 C. Specific dynamic action (SDA) was estimated at different temperatures by taking the difference between oxygen consumption of unfed and fed cichlids at the same levels of activity. SDA represented 22, 20, 19, 33 and 33 percent of the food consumed at 20, 24, 28, 32 and 36 C, when the fish were swimming at 4 cm/second. SDA was generally complete within 36 hours after feeding. Graphs showing energy and material intake, utilization, loss, and scope for growth at each temperature during different experimental periods were developed both in terms of calories per fish per day and calories per gram of fish per day. The evidence suggests that the optimum temperature for growth of this cichlid is near 24 C. Title: Temperature and the bioenergetics of Cichlasoma bimaculatum Author: Sethi, Hari Singh One means of evaluating the temperature requirements of an animal is to determine changes temperature causes in the uses and losses of energy and materials in the food the animal consumes. To develop energy budgets for cichlids (Cichlasoma bimaculatum) at different temperatures (20, 24, 28, 32 and 36 C) data were obtained on food intake, growth (total, fat, and protein), fecal losses, maintenance requirements, and other uses and losses of energy and materials including specific dynamic action, activity, and nitrogen excretion. Starvation experiments were conducted to provide information on the metabolic cost of existence and on adjustments in body composition in the absence of food. Energy expenditure during starvation, estimated from heat of combustion data, was found to increase linearly with temperature over 4, 13 and 20 days of starvation. The caloric cost of existence per fish per day was greatest during the first four days at all temperatures and decreased as starvation was prolonged to 20 days. Caloric losses, and dry weight losses showed essentially the same thing. Protein catabolism increased regularly with temperature and decreased slightly with duration of starvation. Fat catabolism did not vary significantly with temperature but decreased markedly as starvation was prolonged. Food intake, growth, and food conversion efficiency varied greatly with changes in temperature. Cichlids were fed ad libitum on small aquatic worms of the genus Tubifex. For food consumption as well as growth, the optimum temperature dropped from 32 to 28 to 24 C as the experimental period was extended from 5 to 12 to 19 days. Optimum growth in dry weight and calories occurred at the same temperatures. Growth of cichlids through time at 20 and 28 C was nearly linear; at 24 C the curve was exponential. At 32 and 36 C, the growth curves rose and then declined. When the fish were held separately during the experiment, food conversion efficiency of cichlids was highest at 20 C and decreased with increasing temperature. Efficiencies decreased with duration of the experiment. When fish were held in groups during the experiment, efficiency was low at both high and low temperatures. The guts of the cichlids were found to contain food up to 30 hours after an ad libitum meal at all temperatures. They were reasonably empty after 36 hours. Thus, no significant correlation was found between temperature and the length of time necessary for the guts to empty. Food material not absorbed was measured by wet combustion. Percentages of absorption of unrestricted rations were found to be 83, 84, 88, 85 and 69 at 20, 24, 28, 32 and 36 C. Percentages of food absorption were much higher on the restricted ration than on the unrestricted ration. Absorption appears to have been optimal at 28 C. Specific dynamic action (SDA) was estimated at different temperatures by taking the difference between oxygen consumption of unfed and fed cichlids at the same levels of activity. SDA represented 22, 20, 19, 33 and 33 percent of the food consumed at 20, 24, 28, 32 and 36 C, when the fish were swimming at 4 cm/second. SDA was generally complete within 36 hours after feeding. Graphs showing energy and material intake, utilization, loss, and scope for growth at each temperature during different experimental periods were developed both in terms of calories per fish per day and calories per gram of fish per day. The evidence suggests that the optimum temperature for growth of this cichlid is near 24 C. Close

• 75. [Article] Thermal ecology of the garter snakes Thamnophis sirtalis concinnus (Hallowell) and Thamnophis ordinoides (Baird & Girard)

  In recent years, studies dealing with temperature regulation, temperature sensitivity, and physiological responses to temperature in lizards and other reptiles have increased tremendously. It is notable ...

  Citation × Citation Citation Abstract Copy Title: Thermal ecology of the garter snakes Thamnophis sirtalis concinnus (Hallowell) and Thamnophis ordinoides (Baird & Girard) Author: Stewart, Glenn R. In recent years, studies dealing with temperature regulation, temperature sensitivity, and physiological responses to temperature in lizards and other reptiles have increased tremendously. It is notable that snakes have been largely ignored in such studies. This no doubt is due to their less direct relationship to ancestral endotherms. However, problems in the ecology of snakes themselves may be elucidated by studies of this kind. The present study deals with two species of garter snakes ( Thamnophis sirtalis concinnus and Thamnophis ordinoides) which are abundant in Oregon's Willamette Valley. The species sirtalis is the most wide ranging snake in the United States. It is commonly found near permanent water, though occasionally it is encountered in rather dry situations. In contrast to sirtalis, the monotypic species ordinoides is a strictly terrestrial northern Pacific Coast form, which typically is associated with areas of dense vegetation. T. s. concinnus is often seen basking on mild days of the coldest winter months (November-February) while T. ordinoides rarely emerges during these months. The distinct differences in habitat preference and winter behavior exhibited by these snakes suggest differences in thermal preferences and critical levels. To examine this possibility, and the responses of the snakes to thermal acclimation, comparative data on the following variables have been sought: 1) Body temperature of snakes in the field and its relationship to environmental temperatures; 2) body temperature of snakes in a thermal gradient box; 3) critical thermal maximum and minimum; 4) metabolic rate; 5) the effect of thermal acclimation on items two, three, and four. While more investigations are needed to confirm and clarify the results of this study, some tentative conclusions may be stated here: 1) T. s. concinnus and T. ordinoides are diurnal, heliothermic snakes which consistently maintain body temperatures higher than the air and substrate temperatures. 2) T. s. concinnus is more tolerant of seasonally extreme temperatures than T. ordinoides. 3) T. s, concinnus prefers slightly higher body temperatures than T. ordinoides. 4) If temperature tolerances and preferred temperatures are heritable characteristics developed in the phylogeny of the species, these differences probably are primarily related to the difference in distribution of each species as a whole, and secondarily to differences in habitat preference and habit which have resulted from competetive interactions with other species. 5) There are sexual differences in the preferred temperatures of both species, the most significant of which is the relatively high preferred temperature of pregnant females. 6) Initially, the preferred temperatures of both species are inversely related to acclimation temperature. Later, they may be directly related to acclimation temperature. 7) The critical thermal maxima and minima are similar in both species and are directly related to acclimation temperature. However, reacclimation affects the original response differently in the two species. 8) Both species exhibit typical metabolic rate responses to thermal acclimation. 9) Since metabolic rate responses are the same in both species, the greater cold tolerance of T. s. concinnus cannot be attributed to a greater ability to compensate for low temperature. Title: Thermal ecology of the garter snakes Thamnophis sirtalis concinnus (Hallowell) and Thamnophis ordinoides (Baird & Girard) Author: Stewart, Glenn R. In recent years, studies dealing with temperature regulation, temperature sensitivity, and physiological responses to temperature in lizards and other reptiles have increased tremendously. It is notable that snakes have been largely ignored in such studies. This no doubt is due to their less direct relationship to ancestral endotherms. However, problems in the ecology of snakes themselves may be elucidated by studies of this kind. The present study deals with two species of garter snakes ( Thamnophis sirtalis concinnus and Thamnophis ordinoides) which are abundant in Oregon's Willamette Valley. The species sirtalis is the most wide ranging snake in the United States. It is commonly found near permanent water, though occasionally it is encountered in rather dry situations. In contrast to sirtalis, the monotypic species ordinoides is a strictly terrestrial northern Pacific Coast form, which typically is associated with areas of dense vegetation. T. s. concinnus is often seen basking on mild days of the coldest winter months (November-February) while T. ordinoides rarely emerges during these months. The distinct differences in habitat preference and winter behavior exhibited by these snakes suggest differences in thermal preferences and critical levels. To examine this possibility, and the responses of the snakes to thermal acclimation, comparative data on the following variables have been sought: 1) Body temperature of snakes in the field and its relationship to environmental temperatures; 2) body temperature of snakes in a thermal gradient box; 3) critical thermal maximum and minimum; 4) metabolic rate; 5) the effect of thermal acclimation on items two, three, and four. While more investigations are needed to confirm and clarify the results of this study, some tentative conclusions may be stated here: 1) T. s. concinnus and T. ordinoides are diurnal, heliothermic snakes which consistently maintain body temperatures higher than the air and substrate temperatures. 2) T. s. concinnus is more tolerant of seasonally extreme temperatures than T. ordinoides. 3) T. s, concinnus prefers slightly higher body temperatures than T. ordinoides. 4) If temperature tolerances and preferred temperatures are heritable characteristics developed in the phylogeny of the species, these differences probably are primarily related to the difference in distribution of each species as a whole, and secondarily to differences in habitat preference and habit which have resulted from competetive interactions with other species. 5) There are sexual differences in the preferred temperatures of both species, the most significant of which is the relatively high preferred temperature of pregnant females. 6) Initially, the preferred temperatures of both species are inversely related to acclimation temperature. Later, they may be directly related to acclimation temperature. 7) The critical thermal maxima and minima are similar in both species and are directly related to acclimation temperature. However, reacclimation affects the original response differently in the two species. 8) Both species exhibit typical metabolic rate responses to thermal acclimation. 9) Since metabolic rate responses are the same in both species, the greater cold tolerance of T. s. concinnus cannot be attributed to a greater ability to compensate for low temperature. Close

• 76. [Article] Stream Temperature Management Strategies for the Central Umpqua Basin

  Abstract -- This report provides a technical framework to develop a temperature management plan with specific information and examples for the Central Umpqua Basin. Sections include basic stream heating ...

  Citation × Citation Citation Abstract Copy Title: Stream Temperature Management Strategies for the Central Umpqua Basin Abstract -- This report provides a technical framework to develop a temperature management plan with specific information and examples for the Central Umpqua Basin. Sections include basic stream heating concepts, general management considerations, temperature management, and extensive appendices. Title: Stream Temperature Management Strategies for the Central Umpqua Basin Abstract -- This report provides a technical framework to develop a temperature management plan with specific information and examples for the Central Umpqua Basin. Sections include basic stream heating concepts, general management considerations, temperature management, and extensive appendices. Close

• 77. [Article] Salmonberry River Temperature Monitoring-STEP Project

  Abstract -- Results of a STEP project in which volunteers monitor summer temperatures in the Salmonberry River and tributaries. The project began collecting temperatures in 1994. Project history, protocol, ...

  Citation × Citation Citation Abstract Copy Title: Salmonberry River Temperature Monitoring-STEP Project Abstract -- Results of a STEP project in which volunteers monitor summer temperatures in the Salmonberry River and tributaries. The project began collecting temperatures in 1994. Project history, protocol, and results are summarized in pdf documents. Title: Salmonberry River Temperature Monitoring-STEP Project Abstract -- Results of a STEP project in which volunteers monitor summer temperatures in the Salmonberry River and tributaries. The project began collecting temperatures in 1994. Project history, protocol, and results are summarized in pdf documents. Close

• 78. [Image] Steady-State and Transient Wellbore Temperatures during Drilling

  	An extensive literature search was made to locate technical publications and computer programs relating to wellbore temperatures during drilling operations. The search confirmed the need for knowledge ...
  	Citation × Citation Citation Abstract Copy Title: Steady-State and Transient Wellbore Temperatures during Drilling Author: McDonald, W.J. Year: 1976 An extensive literature search was made to locate technical publications and computer programs relating to wellbore temperatures during drilling operations. The search confirmed the need for knowledge of transient and steady state circulating temperatures in the design of geothermal bits. Two approaches were used in calculating borehole temperatures. The steady state solution of Holmes and Swift was programmed and 2100 cases calculated for various borehole configurations. For transient temperature studies, calculations were made for ten borehole configurations. These calculations help emphasize the need for better high temperature bit performance and improved engineering procedures in drilling. The conclusions and recommendations are based on latest available technology for calculating wellbore temperatures Title: Steady-State and Transient Wellbore Temperatures during Drilling Author: McDonald, W.J. Year: 1976 An extensive literature search was made to locate technical publications and computer programs relating to wellbore temperatures during drilling operations. The search confirmed the need for knowledge of transient and steady state circulating temperatures in the design of geothermal bits. Two approaches were used in calculating borehole temperatures. The steady state solution of Holmes and Swift was programmed and 2100 cases calculated for various borehole configurations. For transient temperature studies, calculations were made for ten borehole configurations. These calculations help emphasize the need for better high temperature bit performance and improved engineering procedures in drilling. The conclusions and recommendations are based on latest available technology for calculating wellbore temperatures Close

• 79. [Article] Snow and the ground temperature record of climate change

  Copyrighted by American Geophysical Union

  Citation × Citation Citation Abstract Copy Title: Snow and the ground temperature record of climate change Author: Bartlett, Marshall G., Chapman, David S., Harris, Robert N. Copyrighted by American Geophysical Union Title: Snow and the ground temperature record of climate change Author: Bartlett, Marshall G., Chapman, David S., Harris, Robert N. Copyrighted by American Geophysical Union Close

• 80. [Article] Relationships between Marine Stratus Cloud Optical Depth and Temperature: Inferences from AVHRR Observations

  Studies using International Satellite Cloud Climatology Project (ISCCP) data have reported decreases in cloud optical depth with increasing temperature, thereby suggesting a positive feedback in cloud ...

  Citation × Citation Citation Abstract Copy Title: Relationships between Marine Stratus Cloud Optical Depth and Temperature: Inferences from AVHRR Observations Author: Coakley, James A., Jr., Chang, Fu-Lung Studies using International Satellite Cloud Climatology Project (ISCCP) data have reported decreases in cloud optical depth with increasing temperature, thereby suggesting a positive feedback in cloud optical depth as climate warms. The negative cloud optical depth and temperature relationships are questioned because ISCCP employs threshold assumptions to identify cloudy pixels that have included partly cloudy pixels. This study applies the spatial coherence technique to one month of Advanced Very High Resolution Radiometer (AVHRR) data over the Pacific Ocean to differentiate overcast pixels from the partly cloudy pixels and to reexamine the cloud optical depth–temperature relationships. For low-level marine stratus clouds studied here, retrievals from partly cloudy pixels showed 30%–50% smaller optical depths, 1°–4°C higher cloud temperatures, and slightly larger droplet effective radii, when they were compared to retrievals from the overcast pixels. Despite these biases, retrievals for the overcast and partly cloudy pixels show similar negative cloud optical depth–temperature relationships and their magnitudes agree with the ISCCP results for the midlatitude and subtropical regions. There were slightly negative droplet effective radius–temperature relationships, and considerable positive cloud liquid water content–temperature relationships indicated by aircraft measurements. However, cloud thickness decreases appear to be the main reason why cloud optical depth decreases with increasing temperature. Overall, cloud thickness thinning may explain why similar negative cloud optical depth–temperature relationships are found in both overcast and partly cloudy pixels. In addition, comparing the cloud-top temperature to the air temperature at 740 hPa indicates that cloud-top height generally rises with warming. This suggests that the cloud thinning is mainly due to the ascending of cloud base. The results presented in this study are confined to the midlatitude and subtropical Pacific and may not be applicable to the Tropics or other regions Title: Relationships between Marine Stratus Cloud Optical Depth and Temperature: Inferences from AVHRR Observations Author: Coakley, James A., Jr., Chang, Fu-Lung Studies using International Satellite Cloud Climatology Project (ISCCP) data have reported decreases in cloud optical depth with increasing temperature, thereby suggesting a positive feedback in cloud optical depth as climate warms. The negative cloud optical depth and temperature relationships are questioned because ISCCP employs threshold assumptions to identify cloudy pixels that have included partly cloudy pixels. This study applies the spatial coherence technique to one month of Advanced Very High Resolution Radiometer (AVHRR) data over the Pacific Ocean to differentiate overcast pixels from the partly cloudy pixels and to reexamine the cloud optical depth–temperature relationships. For low-level marine stratus clouds studied here, retrievals from partly cloudy pixels showed 30%–50% smaller optical depths, 1°–4°C higher cloud temperatures, and slightly larger droplet effective radii, when they were compared to retrievals from the overcast pixels. Despite these biases, retrievals for the overcast and partly cloudy pixels show similar negative cloud optical depth–temperature relationships and their magnitudes agree with the ISCCP results for the midlatitude and subtropical regions. There were slightly negative droplet effective radius–temperature relationships, and considerable positive cloud liquid water content–temperature relationships indicated by aircraft measurements. However, cloud thickness decreases appear to be the main reason why cloud optical depth decreases with increasing temperature. Overall, cloud thickness thinning may explain why similar negative cloud optical depth–temperature relationships are found in both overcast and partly cloudy pixels. In addition, comparing the cloud-top temperature to the air temperature at 740 hPa indicates that cloud-top height generally rises with warming. This suggests that the cloud thinning is mainly due to the ascending of cloud base. The results presented in this study are confined to the midlatitude and subtropical Pacific and may not be applicable to the Tropics or other regions Close