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• 21. [Article] Factors influencing density, distribution, and mesohabitat selection of juvenile wild salmonids and residual hatchery winter steelhead

  This is the publisher’s final pdf. The published article is copyrighted by Elsevier and can be found at: http://www.journals.elsevier.com/aquaculture/. To the best of our knowledge, one or more authors ...

  Citation × Citation Citation Abstract Copy Title: Factors influencing density, distribution, and mesohabitat selection of juvenile wild salmonids and residual hatchery winter steelhead Author: Schreck, Carl B., Olson, Douglas E., Schaller, Howard A., Brignon, William R. This is the publisher’s final pdf. The published article is copyrighted by Elsevier and can be found at: http://www.journals.elsevier.com/aquaculture/. To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. Title: Factors influencing density, distribution, and mesohabitat selection of juvenile wild salmonids and residual hatchery winter steelhead Author: Schreck, Carl B., Olson, Douglas E., Schaller, Howard A., Brignon, William R. This is the publisher’s final pdf. The published article is copyrighted by Elsevier and can be found at: http://www.journals.elsevier.com/aquaculture/. To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. Close

• 22. [Article] Proof-of­‐Concept: Automated high­‐frequency measurements of PCO₂ and TCO₂ and real­‐time monitoring of the saturation state of calcium carbonate

  The rapid increase in atmospheric carbon dioxide (CO₂) over the last 250 years has led to the absorption of approximately 550 billion tons of anthropogenic CO₂ by the global ocean. This oceanic uptake ...

  Citation × Citation Citation Abstract Copy Title: Proof-of­‐Concept: Automated high­‐frequency measurements of PCO₂ and TCO₂ and real­‐time monitoring of the saturation state of calcium carbonate Author: Vance, Jesse M. The rapid increase in atmospheric carbon dioxide (CO₂) over the last 250 years has led to the absorption of approximately 550 billion tons of anthropogenic CO₂ by the global ocean. This oceanic uptake of CO₂ has resulted in decreasing pH and alterations to carbonate chemistry, threatening many ecologically and economically important marine species. The majority of biological production takes place on highly dynamic coastal margins, which require instrumentation capable of high-frequency measurements. In practice, measurements of sufficient resolution often do not include all required analytical parameters necessary to constrain the carbonate chemistry in order to investigate biogeochemical processes relevant to ocean acidification. This report provides a proof-of-concept for the development of an instrument designed to make autonomous measurements of the partial pressure of CO₂ (PCO₂) and total CO₂ (TCO₂) in a continuous sample stream at high frequency, based on combination of two existing measurement techniques. The objective is to provide measurements sufficient to constrain the carbonate chemistry in ocean waters while capturing the variability seen over short timescales in estuaries and on coastal margins. By constraining the carbonate chemistry and performing real time calculations of the saturation state of calcium carbonate and other carbonate parameters, this instrument can be utilized as a monitoring tool for fisheries in need of high resolution time series carbonate data. In our combined system, PCO₂ is determined by measuring the infrared absorbance due to CO₂ in the re-circulated gaseous headspace of a shower-type equilibrator. For TCO₂ analysis, a low-flowing seawater sample stream is acidified and passed through a microporous membrane contactor. The evolved CO₂ diffuses into a high-flowing CO₂-free strip-gas stream and is measured by infrared absorbance in the same manner as the PCO₂ method. The results of laboratory testing indicated the instrument is able to resolve TCO₂ changes with 0.5% precision. The system responds to changes in TCO₂ with a time constant of 12 seconds. TCO₂ analysis of gravimetrically prepared liquid carbonate standards and discrete field samples that were cross-analyzed at the Hales lab at Oregon State University indicated the internal accuracy of the system is better than 1%. PCO₂ measurements made with the combined PCO₂/TCO₂ system were within 3.5% of measurements made on synchronously-collected discrete samples preserved with HgCl₂ and subsequently analyzed in the Hales lab. However, absolute accuracy has yet to be validated for both PCO2 and TCO₂ measurements. Field observations carried out at Whiskey Creek Shellfish Hatchery at Netarts Bay on the Oregon coast illustrate the instrument’s ability to capture the high variability seen in the bay. The maximum rates of change seen in carbonate conditions were 123μM hr⁻¹ for TCO₂ and 103μatm hr⁻¹ for PCO₂, corresponding to environmental changes of 2.4°C hr⁻¹ in temperature, and 2.6 psu hr⁻¹ in salinity. Our interpolation method developed to model alkalinity between synchronized TCO₂ and PCO₂ measurements predicts the saturation of calcium carbonate minerals with an internal precision of 1.6%. The error of the resultant high-resolution time series of calcium carbonate saturation is estimated to be less than 3.6%. I conclude that this instrument is capable of producing quality time series of carbonate data at sufficient resolution to be a powerful tool for coastal biogeochemical research and deepening our understanding of the impacts of ocean acidification. Title: Proof-of­‐Concept: Automated high­‐frequency measurements of PCO₂ and TCO₂ and real­‐time monitoring of the saturation state of calcium carbonate Author: Vance, Jesse M. The rapid increase in atmospheric carbon dioxide (CO₂) over the last 250 years has led to the absorption of approximately 550 billion tons of anthropogenic CO₂ by the global ocean. This oceanic uptake of CO₂ has resulted in decreasing pH and alterations to carbonate chemistry, threatening many ecologically and economically important marine species. The majority of biological production takes place on highly dynamic coastal margins, which require instrumentation capable of high-frequency measurements. In practice, measurements of sufficient resolution often do not include all required analytical parameters necessary to constrain the carbonate chemistry in order to investigate biogeochemical processes relevant to ocean acidification. This report provides a proof-of-concept for the development of an instrument designed to make autonomous measurements of the partial pressure of CO₂ (PCO₂) and total CO₂ (TCO₂) in a continuous sample stream at high frequency, based on combination of two existing measurement techniques. The objective is to provide measurements sufficient to constrain the carbonate chemistry in ocean waters while capturing the variability seen over short timescales in estuaries and on coastal margins. By constraining the carbonate chemistry and performing real time calculations of the saturation state of calcium carbonate and other carbonate parameters, this instrument can be utilized as a monitoring tool for fisheries in need of high resolution time series carbonate data. In our combined system, PCO₂ is determined by measuring the infrared absorbance due to CO₂ in the re-circulated gaseous headspace of a shower-type equilibrator. For TCO₂ analysis, a low-flowing seawater sample stream is acidified and passed through a microporous membrane contactor. The evolved CO₂ diffuses into a high-flowing CO₂-free strip-gas stream and is measured by infrared absorbance in the same manner as the PCO₂ method. The results of laboratory testing indicated the instrument is able to resolve TCO₂ changes with 0.5% precision. The system responds to changes in TCO₂ with a time constant of 12 seconds. TCO₂ analysis of gravimetrically prepared liquid carbonate standards and discrete field samples that were cross-analyzed at the Hales lab at Oregon State University indicated the internal accuracy of the system is better than 1%. PCO₂ measurements made with the combined PCO₂/TCO₂ system were within 3.5% of measurements made on synchronously-collected discrete samples preserved with HgCl₂ and subsequently analyzed in the Hales lab. However, absolute accuracy has yet to be validated for both PCO2 and TCO₂ measurements. Field observations carried out at Whiskey Creek Shellfish Hatchery at Netarts Bay on the Oregon coast illustrate the instrument’s ability to capture the high variability seen in the bay. The maximum rates of change seen in carbonate conditions were 123μM hr⁻¹ for TCO₂ and 103μatm hr⁻¹ for PCO₂, corresponding to environmental changes of 2.4°C hr⁻¹ in temperature, and 2.6 psu hr⁻¹ in salinity. Our interpolation method developed to model alkalinity between synchronized TCO₂ and PCO₂ measurements predicts the saturation of calcium carbonate minerals with an internal precision of 1.6%. The error of the resultant high-resolution time series of calcium carbonate saturation is estimated to be less than 3.6%. I conclude that this instrument is capable of producing quality time series of carbonate data at sufficient resolution to be a powerful tool for coastal biogeochemical research and deepening our understanding of the impacts of ocean acidification. Close

• 23. [Article] Are large macroalgal blooms necessarily bad? nutrient impacts on seagrass in upwelling-influenced estuaries

  This is the publisher’s final pdf. The published article is copyrighted by Ecological Society of America and can be found at: http://www.esajournals.org/loi/ecap

  Citation × Citation Citation Abstract Copy Title: Are large macroalgal blooms necessarily bad? nutrient impacts on seagrass in upwelling-influenced estuaries Author: McConville, Sea-oh, Hacker, Sally D., Hessing-Lewis, Margot L., Henderson, Jeremy, Menge, Bruce A. This is the publisher’s final pdf. The published article is copyrighted by Ecological Society of America and can be found at: http://www.esajournals.org/loi/ecap Title: Are large macroalgal blooms necessarily bad? nutrient impacts on seagrass in upwelling-influenced estuaries Author: McConville, Sea-oh, Hacker, Sally D., Hessing-Lewis, Margot L., Henderson, Jeremy, Menge, Bruce A. This is the publisher’s final pdf. The published article is copyrighted by Ecological Society of America and can be found at: http://www.esajournals.org/loi/ecap Close

• 24. [Article] Modeling sage-grouse habitat using a state-and-transition model

  Habitat for wildlife species that depend on sagebrush ecosystems is of great management concern. Evaluating how management activities and climate change may affect the abundance of moderate and high-quality ...

  Citation × Citation Citation Abstract Copy Title: Modeling sage-grouse habitat using a state-and-transition model Author: Evers, Louisa Habitat for wildlife species that depend on sagebrush ecosystems is of great management concern. Evaluating how management activities and climate change may affect the abundance of moderate and high-quality habitat necessitates the development of models that examine vegetation dynamics, but modeling tools for rangeland systems are limited. I developed state-and-transition models using a combination of scientific literature and data for climate, soils, and wildfire to examine how different types of natural events, management activities, changing climate, and potential future vegetation dynamics may interact and affect the abundance of habitat for the greater sage-grouse (Centrocercus urophasianus). Specific periods examined include the era prior to 1850, the current era, and late in the 21st century in southeastern Oregon. A primary purpose of this study was to evaluate the use of climate data to define most event probabilities and, subsequently, the relative mix of ecological states, community phases, and sage-grouse habitat with an eye towards a modeling approach that was objective, repeatable, and transferrable to other locations. Contrary to expectations, model results of the conditions prior to 1850 indicated fire may not have been the most important disturbance factor influencing sage-grouse habitat abundance, merely the most visible. Other, more subtle disturbances that thinned sagebrush density, such as drought, herbivory, and weather-related mortality, may have been equally or more important in shaping sage-grouse habitat. Sage-grouse breeding habitat may have been slightly more abundant than levels currently recommended by sage-grouse biologists, brood-rearing habitat may have been as or more abundant, but wintering habitat may have been less abundant. Under the current conditions, livestock grazing during severe drought, postfire seeding success, juniper expansion probabilities, and the frequency of vegetation treatments were the most important determinants of sage-grouse habitat abundance. The current vegetation trajectory would lead to considerably less nesting, brood-rearing, and wintering habitat than sage-grouse biologists recommend. Model results suggested reducing or eliminating livestock grazing during severe drought, increasing postfire seeding success, and treating at least 10% of the so-called expansion juniper each year was necessary to maintain higher levels of sage-grouse habitat, although nesting and brood-rearing habitat remained in short supply. I examined three potential future climates based on long-term climate trends in southeastern Oregon and modeled climate and ecosystem projections for the Pacific Northwest generally. The first scenario produced warmer and drier conditions than present, the second scenario warmer and wetter conditions in winter, and the third scenario warmer and wetter conditions in summer. The implications for sage-grouse habitat abundance were very different between these three scenarios, but all would likely result in the loss or near complete loss of cooler, moister sagebrush communities important for nesting and brood-rearing. Salt desert shrub and warmer, drier sagebrush communities could expand under the first scenario but would have a high risk of displacement by cheatgrass. Juniper woodlands could increase in density and salt desert shrub may expand slightly under the second scenario. The remaining sagebrush communities would remain at high risk of displacement by cheatgrass. Pinyon-juniper woodland could largely displace sagebrush in the third scenario. Sage-grouse habitat quality likely would decline in all three scenarios and the abundance decrease significantly in the second and third scenario. Title: Modeling sage-grouse habitat using a state-and-transition model Author: Evers, Louisa Habitat for wildlife species that depend on sagebrush ecosystems is of great management concern. Evaluating how management activities and climate change may affect the abundance of moderate and high-quality habitat necessitates the development of models that examine vegetation dynamics, but modeling tools for rangeland systems are limited. I developed state-and-transition models using a combination of scientific literature and data for climate, soils, and wildfire to examine how different types of natural events, management activities, changing climate, and potential future vegetation dynamics may interact and affect the abundance of habitat for the greater sage-grouse (Centrocercus urophasianus). Specific periods examined include the era prior to 1850, the current era, and late in the 21st century in southeastern Oregon. A primary purpose of this study was to evaluate the use of climate data to define most event probabilities and, subsequently, the relative mix of ecological states, community phases, and sage-grouse habitat with an eye towards a modeling approach that was objective, repeatable, and transferrable to other locations. Contrary to expectations, model results of the conditions prior to 1850 indicated fire may not have been the most important disturbance factor influencing sage-grouse habitat abundance, merely the most visible. Other, more subtle disturbances that thinned sagebrush density, such as drought, herbivory, and weather-related mortality, may have been equally or more important in shaping sage-grouse habitat. Sage-grouse breeding habitat may have been slightly more abundant than levels currently recommended by sage-grouse biologists, brood-rearing habitat may have been as or more abundant, but wintering habitat may have been less abundant. Under the current conditions, livestock grazing during severe drought, postfire seeding success, juniper expansion probabilities, and the frequency of vegetation treatments were the most important determinants of sage-grouse habitat abundance. The current vegetation trajectory would lead to considerably less nesting, brood-rearing, and wintering habitat than sage-grouse biologists recommend. Model results suggested reducing or eliminating livestock grazing during severe drought, increasing postfire seeding success, and treating at least 10% of the so-called expansion juniper each year was necessary to maintain higher levels of sage-grouse habitat, although nesting and brood-rearing habitat remained in short supply. I examined three potential future climates based on long-term climate trends in southeastern Oregon and modeled climate and ecosystem projections for the Pacific Northwest generally. The first scenario produced warmer and drier conditions than present, the second scenario warmer and wetter conditions in winter, and the third scenario warmer and wetter conditions in summer. The implications for sage-grouse habitat abundance were very different between these three scenarios, but all would likely result in the loss or near complete loss of cooler, moister sagebrush communities important for nesting and brood-rearing. Salt desert shrub and warmer, drier sagebrush communities could expand under the first scenario but would have a high risk of displacement by cheatgrass. Juniper woodlands could increase in density and salt desert shrub may expand slightly under the second scenario. The remaining sagebrush communities would remain at high risk of displacement by cheatgrass. Pinyon-juniper woodland could largely displace sagebrush in the third scenario. Sage-grouse habitat quality likely would decline in all three scenarios and the abundance decrease significantly in the second and third scenario. Close