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• 31. [Article] Appendix B - Data Collected 4-Aug 2009.zip

  Citation × Citation Citation Abstract Copy Title: Appendix B - Data Collected 4-Aug 2009.zip Author: Arik, Aida D. Title: Appendix B - Data Collected 4-Aug 2009.zip Author: Arik, Aida D. Close

• 32. [Article] A study of wind, oceanic temperature and hydrography in the upwelling area off Peru

  Observations of sea temperature, wind and hydrography obtained during the three months' period of MAM 77 - CUEA experiment (JOINT-II) along the C-line, near 15°S are described. Wind and temperature observations ...

  Citation × Citation Citation Abstract Copy Title: A study of wind, oceanic temperature and hydrography in the upwelling area off Peru Author: Medina, Francisco A. Observations of sea temperature, wind and hydrography obtained during the three months' period of MAM 77 - CUEA experiment (JOINT-II) along the C-line, near 15°S are described. Wind and temperature observations made during March - May 1977 are compared to demonstrate that a relationship exists. Linear correlation analysis was performed on the temperature data and on the alongshore component of wind and wind stress. Auto-correlations and cross-correlations were computed for the temperature and wind. These analyses show that the alongshore fluctuations of the wind are very similar at the different stations, and the wind at each location was favorable for upwelling throughout the period of measurements. Temperature fluctuations in the near-surface, the nearshore and the near-bottom water over the shelf are coherent with temperature changes at a depth of 150 - 200 m over the upper slope. Temperature-wind analysis show that there is a good response of the near-surface temperature to the wind force. The time lag between the wind and the near-surface temperature was about 24 hours nearshore; the wind always led the temperature. Subsurface temperatures were not as well correlated with the alongshore wind, both negative and positive correlations were observed in this analysis, and the time lag between the wind and temperature was variable; on a few occasions the temperature led the wind. Vertical sections of sigma-t and temperature indicate the existence of conditions consistent with upwelling. Oscillation in the wind with periods of several days caused significant changes in the region inshore of 25 km. Title: A study of wind, oceanic temperature and hydrography in the upwelling area off Peru Author: Medina, Francisco A. Observations of sea temperature, wind and hydrography obtained during the three months' period of MAM 77 - CUEA experiment (JOINT-II) along the C-line, near 15°S are described. Wind and temperature observations made during March - May 1977 are compared to demonstrate that a relationship exists. Linear correlation analysis was performed on the temperature data and on the alongshore component of wind and wind stress. Auto-correlations and cross-correlations were computed for the temperature and wind. These analyses show that the alongshore fluctuations of the wind are very similar at the different stations, and the wind at each location was favorable for upwelling throughout the period of measurements. Temperature fluctuations in the near-surface, the nearshore and the near-bottom water over the shelf are coherent with temperature changes at a depth of 150 - 200 m over the upper slope. Temperature-wind analysis show that there is a good response of the near-surface temperature to the wind force. The time lag between the wind and the near-surface temperature was about 24 hours nearshore; the wind always led the temperature. Subsurface temperatures were not as well correlated with the alongshore wind, both negative and positive correlations were observed in this analysis, and the time lag between the wind and temperature was variable; on a few occasions the temperature led the wind. Vertical sections of sigma-t and temperature indicate the existence of conditions consistent with upwelling. Oscillation in the wind with periods of several days caused significant changes in the region inshore of 25 km. Close

• 33. [Article] A spatially explicit network-based model for estimating stream temperature distribution

  The WET-Temp (Watershed Evaluation Tool Temperature) model is designed to take advantage of spatially explicit datasets to predict stream temperature distribution. Datasets describing vegetation cover, ...

  Citation × Citation Citation Abstract Copy Title: A spatially explicit network-based model for estimating stream temperature distribution Author: Cox, Matthew M. The WET-Temp (Watershed Evaluation Tool Temperature) model is designed to take advantage of spatially explicit datasets to predict stream temperature distribution. Datasets describing vegetation cover, stream network locations, elevation and stream discharge are utilized by WET-Temp to quantify geometric relationships between the sun, stream channel and riparian areas. These relationships are used to estimate the energy gained or lost by the stream via various heat flux processes (solar and longwave radiation, evaporation, convection and advection). The sum of these processes is expressed as a differential energy balance equation applied at discrete locations across the stream network. The model describes diurnal temperature dynamics at each of these locations and thus temperature distribution across the entire network. WET-Temp is calibrated to a tributary of the South Santiam River in western Oregon, McDowell Creek. The mean differences between measured and modeled values in McDowell Creek were 0.6°C for daily maximum temperature and 1.3°C for daily minimum temperature. The model was then used to predict maximum and minimum temperatures in an adjacent tributary, Hamilton Creek. The mean differences between modeled and measured values in this paired basin were 1.8°C for daily maximum temperatures and 1.4°C for daily minimum temperatures. Influences of model parameters on modeled temperature distributions are explored in a sensitivity analysis. The ability of WET-Temp to utilize spatially explicit datasets in estimating temperature distributions across stream networks advances the state of the art in modeling stream temperature. Title: A spatially explicit network-based model for estimating stream temperature distribution Author: Cox, Matthew M. The WET-Temp (Watershed Evaluation Tool Temperature) model is designed to take advantage of spatially explicit datasets to predict stream temperature distribution. Datasets describing vegetation cover, stream network locations, elevation and stream discharge are utilized by WET-Temp to quantify geometric relationships between the sun, stream channel and riparian areas. These relationships are used to estimate the energy gained or lost by the stream via various heat flux processes (solar and longwave radiation, evaporation, convection and advection). The sum of these processes is expressed as a differential energy balance equation applied at discrete locations across the stream network. The model describes diurnal temperature dynamics at each of these locations and thus temperature distribution across the entire network. WET-Temp is calibrated to a tributary of the South Santiam River in western Oregon, McDowell Creek. The mean differences between measured and modeled values in McDowell Creek were 0.6°C for daily maximum temperature and 1.3°C for daily minimum temperature. The model was then used to predict maximum and minimum temperatures in an adjacent tributary, Hamilton Creek. The mean differences between modeled and measured values in this paired basin were 1.8°C for daily maximum temperatures and 1.4°C for daily minimum temperatures. Influences of model parameters on modeled temperature distributions are explored in a sensitivity analysis. The ability of WET-Temp to utilize spatially explicit datasets in estimating temperature distributions across stream networks advances the state of the art in modeling stream temperature. Close

• 34. [Article] Drop it like it’s Hot : Combining DTS and Temperature Modeling to Evaluate Stream Restoration on the Middle Fork of the John Day River

  Temperature is a key factor for salmonid health and is an important restoration metric on the Middle Fork of the John Day River in northeast Oregon. In the past century, dredge mining, deforestation, and ...

  Citation × Citation Citation Abstract Copy Title: Drop it like it’s Hot : Combining DTS and Temperature Modeling to Evaluate Stream Restoration on the Middle Fork of the John Day River Author: Hall, Austin (Austin Garrett) Temperature is a key factor for salmonid health and is an important restoration metric on the Middle Fork of the John Day River in northeast Oregon. In the past century, dredge mining, deforestation, and overgrazing have degraded stream habitat and resulted in greater daytime stream temperatures in the region. Recent restoration efforts have focused on mitigating these anthropogenic disturbances by reestablishing floodplain connections, replanting riparian vegetation, and improving instream habitat features and sediment. To evaluate these restoration projects, the Middle Fork of the John Day River was designated as an intensively monitored watershed in 2008, setting the stage for a 10-year temperature monitoring study. Temperatures measured during the summers of 2013 and 2014 add to the wealth of high resolution distributed temperature sensing (DTS) data collected by Oregon State University and serve as the first post-restoration data for a 2012 restoration project. Utilizing these data in coordination with the model, Heat Source, temperature change from two large restoration projects was quantified. Results from the study emphasize the significance of stream area and riparian vegetation on stream temperatures on the Middle Fork. Phase 2 of the Oxbow Tailings Restoration, completed in 2012, filled over a channel used for past dredge mining activities, reducing stream surface area and restoring the bifurcated channel to its historic south path. Findings show that this project has buffered daily stream temperatures, leading to decreases in maximum and daytime temperatures and increases in nightly temperatures for early August. Maximum and afternoon temperatures were shown to decrease by 0.65 °C and 0.91 °C, respectively, while nightly temperatures increased 0.85 °C. Continuing immediately downstream of the Phase 2 project, Phase 3 is currently in its final stages of construction. Objectives of Phase 3 seek to increase stream meanders, restore vegetation, and reconnect the stream to the adjacent valley and Ruby Creek tributary. Projecting future temperatures shows that the longer, wider restored channel increases afternoon temperature by 0.53 °C. Unlike Phase 2, changes to maximum and nightly temperatures were negligable. Altering the design width and vegetation for the restored channel revealed strong linear correlations to stream temperature, providing a simple tool that can be used to estimate temperature difference for future areal and shading scenarios. Title: Drop it like it’s Hot : Combining DTS and Temperature Modeling to Evaluate Stream Restoration on the Middle Fork of the John Day River Author: Hall, Austin (Austin Garrett) Temperature is a key factor for salmonid health and is an important restoration metric on the Middle Fork of the John Day River in northeast Oregon. In the past century, dredge mining, deforestation, and overgrazing have degraded stream habitat and resulted in greater daytime stream temperatures in the region. Recent restoration efforts have focused on mitigating these anthropogenic disturbances by reestablishing floodplain connections, replanting riparian vegetation, and improving instream habitat features and sediment. To evaluate these restoration projects, the Middle Fork of the John Day River was designated as an intensively monitored watershed in 2008, setting the stage for a 10-year temperature monitoring study. Temperatures measured during the summers of 2013 and 2014 add to the wealth of high resolution distributed temperature sensing (DTS) data collected by Oregon State University and serve as the first post-restoration data for a 2012 restoration project. Utilizing these data in coordination with the model, Heat Source, temperature change from two large restoration projects was quantified. Results from the study emphasize the significance of stream area and riparian vegetation on stream temperatures on the Middle Fork. Phase 2 of the Oxbow Tailings Restoration, completed in 2012, filled over a channel used for past dredge mining activities, reducing stream surface area and restoring the bifurcated channel to its historic south path. Findings show that this project has buffered daily stream temperatures, leading to decreases in maximum and daytime temperatures and increases in nightly temperatures for early August. Maximum and afternoon temperatures were shown to decrease by 0.65 °C and 0.91 °C, respectively, while nightly temperatures increased 0.85 °C. Continuing immediately downstream of the Phase 2 project, Phase 3 is currently in its final stages of construction. Objectives of Phase 3 seek to increase stream meanders, restore vegetation, and reconnect the stream to the adjacent valley and Ruby Creek tributary. Projecting future temperatures shows that the longer, wider restored channel increases afternoon temperature by 0.53 °C. Unlike Phase 2, changes to maximum and nightly temperatures were negligable. Altering the design width and vegetation for the restored channel revealed strong linear correlations to stream temperature, providing a simple tool that can be used to estimate temperature difference for future areal and shading scenarios. Close

• 35. [Article] Temperature and water potential effects on physiological functions of sudangrass (Sorghum vulgare var. Piper)

  Temperature and water potential effects on the growth, transpiration, total nonstructural carbohydrate (TNC) content, and nutrient uptake of sudangrass (Sorghum vulgare var. piper) were investigated in ...

  Citation × Citation Citation Abstract Copy Title: Temperature and water potential effects on physiological functions of sudangrass (Sorghum vulgare var. Piper) Author: Young, Richard Su-Shung Temperature and water potential effects on the growth, transpiration, total nonstructural carbohydrate (TNC) content, and nutrient uptake of sudangrass (Sorghum vulgare var. piper) were investigated in laboratory experiments. The effect of nitrogen supply on the growth and nutrient uptake at constant soil water potential was also investigated in this study. Two week old seedlings were used for all experiments. Soil temperatures of 10.0, 15.6, 21.1, 26.7, 32.2 and 37.8 C were tested. Plants were grown at soil water potentials of -0.35 and -2.50 bars for 10 days using the polyethylene glycol semi-permeable membrane technique for controlling soil water potential. Air temperature remained constant at 26.7 C during these experiments. Air temperatures of 18.3, 22.8, 26.7 and 32.2 C were tested in a second series of experiments, with the soil water potential and soil temperature constant at -0.35 bars and 26.7 C. Further experiment.; were conducted with nitrogen levels in the nutrient solutions of 0, 10, 25 and 100 ppm. The soil temperature and soil water potential were kept constant in these experiments. Finally, the effect of soil temperature and soil water potential on plant water potential at soil water potentials of -0.35, -0.70, -1.50 and -2.50 bars was measured. Growth rate increased with soil temperature up to an optimum temperature, then decreased at higher temperatures for both shoots and roots at both soil water potentials tested. The highest growth rate was at 30 C for the shoots and 26 C for the roots. The rate was higher at -0.35 bars than at -2.50 bars for both shoots and roots. By varying the air temperature, the rate of growth was found to be highest at the air temperature of 26.7 C. The nitrogen level of 100 ppm in the nutrient solution produced the highest growth rate. The dry matter weight increased exponentially with time in all experiments. It was concluded that the soil temperature of 30 C, air temperature of 26.7 C and a soil water potential of -0.35 bars was optimal for sudangrass growth. Transpiration rates increased exponentially as a function of time for all treatments. Transpiration rates (cm³/day) increased as the soil temperature increased at both soil water potentials. The rate at -2.50 bars was lower than at -0.35 bars. The transpiration rate also increased with increasing air temperature independent of RH differences. An equilibrium content of N, P, K, Ca, Mg, S, Mn and Zn in the plant material at each combination of treatment variables was determined based on the assumption that equilibrium was attained as time progressed. The maximum concentration of N occurred at a temperature of about 30 C in both shoots and roots, while the concentration was lower at -0.35 bars than at -2.50 bars. The concentration of P increased with soil temperature, in the shoot, but reached a maximum at 30 C in the roots. The concentration at -0.35 bars was lower than at -2.50 bars. The concentrations of K, Ca and S were not significantly different at the two water potentials. The concentration of K was highest at about 30 C in both shoots and roots. The concentration of Ca was highest at about 22 C in both shoots and roots. The suflfur concentration of the shoots increased as soil temperature increased, but a maximum concentration in the roots occurred at 30 C. The concentration of Mn was highest at 26.7 C in the shoots and at 21.1 C in the roots. Concentrations of Mn at -0.35 bars were lower than at -2.50 bars. The Zn concentration increased as soil temperature increased for both shoots and roots. The concentration at -0.35 bars was lower than at -2.50 bars. In the experiments with air temperature as the variable the concentration of N in the shoots was highest at 26.7 C, but decreased in the roots as air temperature increased. The concentration of P decreased with increasing air temperature in both shoots and roots. The concentration of K increased with increasing air temperature in the shoots but decreased in the roots. The concentration of Ca was highest at 26.7 C in the shoots, and increased with increasing air temperature in the roots. The concentration of Mg in the shoots was highest at 26.7 C, while the concentration in the roots slightly decreased with increasing air temperature. The concentration of S decreased with increasing air temperature in both shoots and roots. The Mn concentration was highest at 26.7 C in both shoots and roots. The concentration of Zn increased as air temperature increased. The increase in the roots was greater than in the shoots. The concentration of N, P. Ca and Mg in both shoots and roots increased as the nitrogen level of the nutrient solution increased. The concentration of K in the shoots increased with increasing N level, but in the roots, a maximum concentration occurred at 25 ppm. The concentration of S in the shoots increased as the nitrogen level increased but decreased in the roots. Mn concentrations increased in the shoots but decreased in the roots with increasing nitrogen supply. The Zn concentration increased in the shoots, but decreased in the roots as the N level increased. The total nonstructural carbohydrate (TNC) content decreased as the soil temperature increased. The decrease was 10 percent at a soil water potential of -0.35 bars and 2 percent at a soil water potential of -2.50 bars as the soil temperature increased from 10.0 to 32.2 C. The TNC also decreased as the air temperature increased. The decrease was 8.3 percent as the air temperature increased from 18.3 to 32.2 C. This decrease was attributed to increased respiration and increased translocation from shoots to roots. The leaf water potential (Ψ[subscript c]) and osmotic potential (Ψ[subscript π]) decreased with time at all soil temperature and soil water potential combinations. The decrease was greater at low temperatures than at high temperatures for all soil water potentials. As the soil water potential decreased from -0.35 to -2.50 bars, the leaf water potential (Ψ[subscript c]) and osmotic potential (Ψ[subscript π]) decreased at all soil temperatures. The decrease is osmotic potential (Ψ[subscript π]) was greater than the decrease in leaf water potential (Ψ[subscript c]). The turgor pressure decreased with decreasing soil temperature, and slightly increased with decreasing soil water potential. The growth rate was correlated with turgor pressure. The relationship between turgor pressure and growth rate varied with soil temperature and soil water potential. It was concluded that this relationship may have been the primary growth controlling mechanism. The rate of nutrient uptake increased with increasing water uptake at both water potentials of -0.35 and -2.50 bars. The ion concentration in the transpiration stream was lower at -0.35 bars than at -2.50 bars. The concentration increased slightly with increasing soil temperature at both soil water potentials tested, but relatively more at -2.50 bars. Title: Temperature and water potential effects on physiological functions of sudangrass (Sorghum vulgare var. Piper) Author: Young, Richard Su-Shung Temperature and water potential effects on the growth, transpiration, total nonstructural carbohydrate (TNC) content, and nutrient uptake of sudangrass (Sorghum vulgare var. piper) were investigated in laboratory experiments. The effect of nitrogen supply on the growth and nutrient uptake at constant soil water potential was also investigated in this study. Two week old seedlings were used for all experiments. Soil temperatures of 10.0, 15.6, 21.1, 26.7, 32.2 and 37.8 C were tested. Plants were grown at soil water potentials of -0.35 and -2.50 bars for 10 days using the polyethylene glycol semi-permeable membrane technique for controlling soil water potential. Air temperature remained constant at 26.7 C during these experiments. Air temperatures of 18.3, 22.8, 26.7 and 32.2 C were tested in a second series of experiments, with the soil water potential and soil temperature constant at -0.35 bars and 26.7 C. Further experiment.; were conducted with nitrogen levels in the nutrient solutions of 0, 10, 25 and 100 ppm. The soil temperature and soil water potential were kept constant in these experiments. Finally, the effect of soil temperature and soil water potential on plant water potential at soil water potentials of -0.35, -0.70, -1.50 and -2.50 bars was measured. Growth rate increased with soil temperature up to an optimum temperature, then decreased at higher temperatures for both shoots and roots at both soil water potentials tested. The highest growth rate was at 30 C for the shoots and 26 C for the roots. The rate was higher at -0.35 bars than at -2.50 bars for both shoots and roots. By varying the air temperature, the rate of growth was found to be highest at the air temperature of 26.7 C. The nitrogen level of 100 ppm in the nutrient solution produced the highest growth rate. The dry matter weight increased exponentially with time in all experiments. It was concluded that the soil temperature of 30 C, air temperature of 26.7 C and a soil water potential of -0.35 bars was optimal for sudangrass growth. Transpiration rates increased exponentially as a function of time for all treatments. Transpiration rates (cm³/day) increased as the soil temperature increased at both soil water potentials. The rate at -2.50 bars was lower than at -0.35 bars. The transpiration rate also increased with increasing air temperature independent of RH differences. An equilibrium content of N, P, K, Ca, Mg, S, Mn and Zn in the plant material at each combination of treatment variables was determined based on the assumption that equilibrium was attained as time progressed. The maximum concentration of N occurred at a temperature of about 30 C in both shoots and roots, while the concentration was lower at -0.35 bars than at -2.50 bars. The concentration of P increased with soil temperature, in the shoot, but reached a maximum at 30 C in the roots. The concentration at -0.35 bars was lower than at -2.50 bars. The concentrations of K, Ca and S were not significantly different at the two water potentials. The concentration of K was highest at about 30 C in both shoots and roots. The concentration of Ca was highest at about 22 C in both shoots and roots. The suflfur concentration of the shoots increased as soil temperature increased, but a maximum concentration in the roots occurred at 30 C. The concentration of Mn was highest at 26.7 C in the shoots and at 21.1 C in the roots. Concentrations of Mn at -0.35 bars were lower than at -2.50 bars. The Zn concentration increased as soil temperature increased for both shoots and roots. The concentration at -0.35 bars was lower than at -2.50 bars. In the experiments with air temperature as the variable the concentration of N in the shoots was highest at 26.7 C, but decreased in the roots as air temperature increased. The concentration of P decreased with increasing air temperature in both shoots and roots. The concentration of K increased with increasing air temperature in the shoots but decreased in the roots. The concentration of Ca was highest at 26.7 C in the shoots, and increased with increasing air temperature in the roots. The concentration of Mg in the shoots was highest at 26.7 C, while the concentration in the roots slightly decreased with increasing air temperature. The concentration of S decreased with increasing air temperature in both shoots and roots. The Mn concentration was highest at 26.7 C in both shoots and roots. The concentration of Zn increased as air temperature increased. The increase in the roots was greater than in the shoots. The concentration of N, P. Ca and Mg in both shoots and roots increased as the nitrogen level of the nutrient solution increased. The concentration of K in the shoots increased with increasing N level, but in the roots, a maximum concentration occurred at 25 ppm. The concentration of S in the shoots increased as the nitrogen level increased but decreased in the roots. Mn concentrations increased in the shoots but decreased in the roots with increasing nitrogen supply. The Zn concentration increased in the shoots, but decreased in the roots as the N level increased. The total nonstructural carbohydrate (TNC) content decreased as the soil temperature increased. The decrease was 10 percent at a soil water potential of -0.35 bars and 2 percent at a soil water potential of -2.50 bars as the soil temperature increased from 10.0 to 32.2 C. The TNC also decreased as the air temperature increased. The decrease was 8.3 percent as the air temperature increased from 18.3 to 32.2 C. This decrease was attributed to increased respiration and increased translocation from shoots to roots. The leaf water potential (Ψ[subscript c]) and osmotic potential (Ψ[subscript π]) decreased with time at all soil temperature and soil water potential combinations. The decrease was greater at low temperatures than at high temperatures for all soil water potentials. As the soil water potential decreased from -0.35 to -2.50 bars, the leaf water potential (Ψ[subscript c]) and osmotic potential (Ψ[subscript π]) decreased at all soil temperatures. The decrease is osmotic potential (Ψ[subscript π]) was greater than the decrease in leaf water potential (Ψ[subscript c]). The turgor pressure decreased with decreasing soil temperature, and slightly increased with decreasing soil water potential. The growth rate was correlated with turgor pressure. The relationship between turgor pressure and growth rate varied with soil temperature and soil water potential. It was concluded that this relationship may have been the primary growth controlling mechanism. The rate of nutrient uptake increased with increasing water uptake at both water potentials of -0.35 and -2.50 bars. The ion concentration in the transpiration stream was lower at -0.35 bars than at -2.50 bars. The concentration increased slightly with increasing soil temperature at both soil water potentials tested, but relatively more at -2.50 bars. Close

• 36. [Article] Development and Testing of Single-Parameter Precipitation Distributions

  This is the publisher’s final pdf. The published article is copyrighted by American Geophysical Union and can be found at: http://sites.agu.org/.

  Citation × Citation Citation Abstract Copy Title: Development and Testing of Single-Parameter Precipitation Distributions Author: Haith, Douglas A., Selker, John S. This is the publisher’s final pdf. The published article is copyrighted by American Geophysical Union and can be found at: http://sites.agu.org/. Title: Development and Testing of Single-Parameter Precipitation Distributions Author: Haith, Douglas A., Selker, John S. This is the publisher’s final pdf. The published article is copyrighted by American Geophysical Union and can be found at: http://sites.agu.org/. Close

• 37. [Article] Mid-Latitude (30°–60° N) climatic warming inferred by combining borehole temperatures with surface air temperatures

  copyrighted by American Geophysical Union

  Citation × Citation Citation Abstract Copy Title: Mid-Latitude (30°–60° N) climatic warming inferred by combining borehole temperatures with surface air temperatures Author: Harris, Robert N., Chapman, David S. copyrighted by American Geophysical Union Title: Mid-Latitude (30°–60° N) climatic warming inferred by combining borehole temperatures with surface air temperatures Author: Harris, Robert N., Chapman, David S. copyrighted by American Geophysical Union Close

• 38. [Article] Climate change in India inferred from geothermal observations

  copyrighted by American Geophysical Union

  Citation × Citation Citation Abstract Copy Title: Climate change in India inferred from geothermal observations Author: Harris, Robert N., Rao, R. U. M., Roy, Sukanta, Chapman, David S. copyrighted by American Geophysical Union Title: Climate change in India inferred from geothermal observations Author: Harris, Robert N., Rao, R. U. M., Roy, Sukanta, Chapman, David S. copyrighted by American Geophysical Union Close

• 39. [Article] Effects of temperature and other abiotic and biotic factors on development and survival of the immature stages of the alfalfa leafcutting bee, Megachile pacifica (Panzer) (=rotundata (F.)) (Hymenoptera:Megachilidae)

  Larval mortality of leafcutting bee, Megachile pacifica (Panzer) (= rotundata (F.)), is high, usually exceeding 50%. Parasites and predators are not a limiting factor in the survival of the progeny. The ...

  Citation × Citation Citation Abstract Copy Title: Effects of temperature and other abiotic and biotic factors on development and survival of the immature stages of the alfalfa leafcutting bee, Megachile pacifica (Panzer) (=rotundata (F.)) (Hymenoptera:Megachilidae) Author: Undurraga O., Jaime M. Larval mortality of leafcutting bee, Megachile pacifica (Panzer) (= rotundata (F.)), is high, usually exceeding 50%. Parasites and predators are not a limiting factor in the survival of the progeny. The disease chalk brood has been an important mortality factor since 1974. Inadequate food supply, pollen and nectar, may affect the survival of the progeny. Genetic differences within and between populations and the saponin content of alfalfa leaves do not affect brood production or survival. Domicile design and protection may also have a great influence on survival. Temperatures exceeding 50°C occur in cells when nesting material receives direct sunlight or when nesting material is housed in domiciles with poor ventilation and insulation. There are temperature differences between cells in a series, between nest positions within a domicile, and between types of nesting materials. There is no direct relationship between ambient and cell temperatures because the latter are influenced by exposure, nesting media, placement, and domicile structure. High internal bee body temperatures may occur during most bee activities, excluding resting. The effects of high temperatures on the adult bee or the eggs she contains are not known. Although larval development can proceed at temperatures below 21°C, survival is reduced. Adult activity, like metabolic larval development, can be conditioned to unusually high or low temperatures; thus, there is no absolute temperature threshold for development or activity in this bee. Eggs and young larvae reared at a constant 30°C had over 85% survival, in most years. An ambient temperature of 45°C applied for one to three hours resulted in a higher mortality of eggs and early instars than the control temperature of 30°C; at 50°C, mortality was complete. Exceptions were obtained for either situation. Half hour exposure at 50°C ambient temperature was also detrimental to immatures. An ambient temperature of 40°C in general does not affect survival of immatures. In-cell temperatures were at least 5°C lower than ambient temperatures in incubators during treatments. Repeating heat treatments on two or more days was not as severe as the duration of treatments. Larvae showed heat tolerance when exposed to two to three hours at 45°C but not to one hour, but some exceptions occurred. The mechanism for heat tolerance is not well understood, and may be related to a conditioning of individuals to high temperatures. A seasonal effect on survival was obtained and appears not to be related to the age of the laying females, nor to the generations, but rather to the thermal history to which the immatures were exposed. Heat susceptibility of eggs and early instars seemed to be similar. Fourth and fifth instars were the most heat tolerant of all larval stages. Exposure of young larvae to low temperatures before they were exposed to high temperatures did not increase mortality. However, sublethal high temperatures were generally less harmful to the immatures that were conditioned but this acclimation of the larvae did not occur in every test. Upper threshold temperature limits cannot be precisely defined, nevertheless, cell temperatures over 40°C result in egg and larval mortality. Brief exposure to 45°C was the upper limit that developing pupae could tolerate; 50°C was lethal. Pupae were most heat sensitive between three and six days before emergence. When exposed to high temperatures, pupae and emerging adults were able to arrest development. Pupae and emerging adults can be conditioned to tolerate short exposures to lethal temperatures up to seven days before emergence. Low temperatures did not affect the survival of pupae. Development of pupae and emerging adults could be arrested for up to a week at 15.6°C without harmful effect. Development and emergence proceed at 21 °C, but pupae need at least 2.5 hours per day of temperatures above 21°C to survive when not in an arrested state. Pupae not exposed to temperature above 29°C during 24 hours, emerged normally. Incubation at 29.5°C for less than 10 hours per day delayed the emergence. Pupae maintained at 15.6 °C for 22 hours per day for 8 days or for 20 hours per day for 16 days emerged after a delay longer than the period of cold. Cooling the emerging bees after high temperature treatment appeared to be more detrimental than cooling before exposures to high temperatures. The detrimental effect of extreme temperatures was shown on the survival of eggs, young larvae, and pupae, but possible chronic effects on later stadia were not studied. Title: Effects of temperature and other abiotic and biotic factors on development and survival of the immature stages of the alfalfa leafcutting bee, Megachile pacifica (Panzer) (=rotundata (F.)) (Hymenoptera:Megachilidae) Author: Undurraga O., Jaime M. Larval mortality of leafcutting bee, Megachile pacifica (Panzer) (= rotundata (F.)), is high, usually exceeding 50%. Parasites and predators are not a limiting factor in the survival of the progeny. The disease chalk brood has been an important mortality factor since 1974. Inadequate food supply, pollen and nectar, may affect the survival of the progeny. Genetic differences within and between populations and the saponin content of alfalfa leaves do not affect brood production or survival. Domicile design and protection may also have a great influence on survival. Temperatures exceeding 50°C occur in cells when nesting material receives direct sunlight or when nesting material is housed in domiciles with poor ventilation and insulation. There are temperature differences between cells in a series, between nest positions within a domicile, and between types of nesting materials. There is no direct relationship between ambient and cell temperatures because the latter are influenced by exposure, nesting media, placement, and domicile structure. High internal bee body temperatures may occur during most bee activities, excluding resting. The effects of high temperatures on the adult bee or the eggs she contains are not known. Although larval development can proceed at temperatures below 21°C, survival is reduced. Adult activity, like metabolic larval development, can be conditioned to unusually high or low temperatures; thus, there is no absolute temperature threshold for development or activity in this bee. Eggs and young larvae reared at a constant 30°C had over 85% survival, in most years. An ambient temperature of 45°C applied for one to three hours resulted in a higher mortality of eggs and early instars than the control temperature of 30°C; at 50°C, mortality was complete. Exceptions were obtained for either situation. Half hour exposure at 50°C ambient temperature was also detrimental to immatures. An ambient temperature of 40°C in general does not affect survival of immatures. In-cell temperatures were at least 5°C lower than ambient temperatures in incubators during treatments. Repeating heat treatments on two or more days was not as severe as the duration of treatments. Larvae showed heat tolerance when exposed to two to three hours at 45°C but not to one hour, but some exceptions occurred. The mechanism for heat tolerance is not well understood, and may be related to a conditioning of individuals to high temperatures. A seasonal effect on survival was obtained and appears not to be related to the age of the laying females, nor to the generations, but rather to the thermal history to which the immatures were exposed. Heat susceptibility of eggs and early instars seemed to be similar. Fourth and fifth instars were the most heat tolerant of all larval stages. Exposure of young larvae to low temperatures before they were exposed to high temperatures did not increase mortality. However, sublethal high temperatures were generally less harmful to the immatures that were conditioned but this acclimation of the larvae did not occur in every test. Upper threshold temperature limits cannot be precisely defined, nevertheless, cell temperatures over 40°C result in egg and larval mortality. Brief exposure to 45°C was the upper limit that developing pupae could tolerate; 50°C was lethal. Pupae were most heat sensitive between three and six days before emergence. When exposed to high temperatures, pupae and emerging adults were able to arrest development. Pupae and emerging adults can be conditioned to tolerate short exposures to lethal temperatures up to seven days before emergence. Low temperatures did not affect the survival of pupae. Development of pupae and emerging adults could be arrested for up to a week at 15.6°C without harmful effect. Development and emergence proceed at 21 °C, but pupae need at least 2.5 hours per day of temperatures above 21°C to survive when not in an arrested state. Pupae not exposed to temperature above 29°C during 24 hours, emerged normally. Incubation at 29.5°C for less than 10 hours per day delayed the emergence. Pupae maintained at 15.6 °C for 22 hours per day for 8 days or for 20 hours per day for 16 days emerged after a delay longer than the period of cold. Cooling the emerging bees after high temperature treatment appeared to be more detrimental than cooling before exposures to high temperatures. The detrimental effect of extreme temperatures was shown on the survival of eggs, young larvae, and pupae, but possible chronic effects on later stadia were not studied. Close

• 40. [Article] Effect of climate change on water temperature and attainment of water temperature criteria in the Yaquina Estuary, Oregon (USA)

  To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. This is the publisher’s final pdf. The published article is copyrighted by Elsevier ...

  Citation × Citation Citation Abstract Copy Title: Effect of climate change on water temperature and attainment of water temperature criteria in the Yaquina Estuary, Oregon (USA) Author: Sharp, Darrin, Collura, T. Chris Mochon, Brown, Cheryl A. To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. This is the publisher’s final pdf. The published article is copyrighted by Elsevier and can be found at: http://www.journals.elsevier.com/estuarine-coastal-and-shelf-science/ Title: Effect of climate change on water temperature and attainment of water temperature criteria in the Yaquina Estuary, Oregon (USA) Author: Sharp, Darrin, Collura, T. Chris Mochon, Brown, Cheryl A. To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. This is the publisher’s final pdf. The published article is copyrighted by Elsevier and can be found at: http://www.journals.elsevier.com/estuarine-coastal-and-shelf-science/ Close