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• 121. [Article] Power-law residence time distribution in the hyporheic zone of a 2nd-order mountain stream

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

  Citation × Citation Citation Abstract Copy Title: Power-law residence time distribution in the hyporheic zone of a 2nd-order mountain stream Author: Haggerty, Roy, Wondzell, Steven M., Johnson, Matthew A. This is the publisher’s final pdf. The published article is copyrighted by the American Geophysical Union and can be found at: http://www.agu.org/journals/gl/. Title: Power-law residence time distribution in the hyporheic zone of a 2nd-order mountain stream Author: Haggerty, Roy, Wondzell, Steven M., Johnson, Matthew A. This is the publisher’s final pdf. The published article is copyrighted by the American Geophysical Union and can be found at: http://www.agu.org/journals/gl/. Close

• 122. [Article] Upwelling around Cabo Frio, Brazil : the importance of wind stress curl

  copyrighted by American Geophysical Union

  Citation × Citation Citation Abstract Copy Title: Upwelling around Cabo Frio, Brazil : the importance of wind stress curl Author: Castelao, Renato M., Barth, John A. copyrighted by American Geophysical Union Title: Upwelling around Cabo Frio, Brazil : the importance of wind stress curl Author: Castelao, Renato M., Barth, John A. copyrighted by American Geophysical Union Close

• 123. [Article] Design and construction of demonstration/research wetlands for treatment of dairy farm wastewater

  "EPA 600/R-93/105"

  Citation × Citation Citation Abstract Copy Title: Design and construction of demonstration/research wetlands for treatment of dairy farm wastewater Author: Gamroth, M. J. (Michael J.), Moore, James A. (James Allan), 1939- "EPA 600/R-93/105" Title: Design and construction of demonstration/research wetlands for treatment of dairy farm wastewater Author: Gamroth, M. J. (Michael J.), Moore, James A. (James Allan), 1939- "EPA 600/R-93/105" Close

• 124. [Article] Role of colloids in upper ocean biogeochemistry in the northeast Pacific Ocean elucidated from ²³⁸U-²³⁴Th disequilibria

  Detailed upper ocean profiles of 234Th in dissolved (< 10,000 Daltons), colloidal (10,000 Da–O.45 μm), and particulate (>0.45 μm) forms were measured at a station (46º45′N, 126ºW) in the northeast Pacific Ocean. ...

  Citation × Citation Citation Abstract Copy Title: Role of colloids in upper ocean biogeochemistry in the northeast Pacific Ocean elucidated from ²³⁸U-²³⁴Th disequilibria Author: Huh, Chih-An, Prahl, Fredrick Detailed upper ocean profiles of 234Th in dissolved (< 10,000 Daltons), colloidal (10,000 Da–O.45 μm), and particulate (>0.45 μm) forms were measured at a station (46º45′N, 126ºW) in the northeast Pacific Ocean. On average, dissolved, colloidal, and particulate 234Th accounted for ~78, 12, and 10% of the total 234Th in the cuphotic zone (()–100 m). A highly positive correlation exists between colloidal 234Th and chlorophyll a; both are characterized by higher concentrations in surface waters, a subsurface maximum at 55 m in the seasonal thermocline, and undetectable levels below the euphotic zone. POC : Chl α ratios in the water column suggest phytoplankton as primary producers of the colloidal material. Scavenging residence times of dissolved, colloidal, and particulate 234Th with respect to their removal processes in the euphotic zone are ~50, 6, and 8 d. The scavenging rate constant of Th apparently increases with the concentration of colloids. Title: Role of colloids in upper ocean biogeochemistry in the northeast Pacific Ocean elucidated from ²³⁸U-²³⁴Th disequilibria Author: Huh, Chih-An, Prahl, Fredrick Detailed upper ocean profiles of 234Th in dissolved (< 10,000 Daltons), colloidal (10,000 Da–O.45 μm), and particulate (>0.45 μm) forms were measured at a station (46º45′N, 126ºW) in the northeast Pacific Ocean. On average, dissolved, colloidal, and particulate 234Th accounted for ~78, 12, and 10% of the total 234Th in the cuphotic zone (()–100 m). A highly positive correlation exists between colloidal 234Th and chlorophyll a; both are characterized by higher concentrations in surface waters, a subsurface maximum at 55 m in the seasonal thermocline, and undetectable levels below the euphotic zone. POC : Chl α ratios in the water column suggest phytoplankton as primary producers of the colloidal material. Scavenging residence times of dissolved, colloidal, and particulate 234Th with respect to their removal processes in the euphotic zone are ~50, 6, and 8 d. The scavenging rate constant of Th apparently increases with the concentration of colloids. Close

• 125. [Article] Modeled ocean circulation in Nares Strait and its dependence on landfast-ice cover

  Access to this item has been restricted by repository administrators at the request of the publisher until June 30, 2016.

  Citation × Citation Citation Abstract Copy Title: Modeled ocean circulation in Nares Strait and its dependence on landfast-ice cover Author: Padman, Laurie, Shroyer, Emily L., Samelson, Roger M., Münchow, Andreas Access to this item has been restricted by repository administrators at the request of the publisher until June 30, 2016. Title: Modeled ocean circulation in Nares Strait and its dependence on landfast-ice cover Author: Padman, Laurie, Shroyer, Emily L., Samelson, Roger M., Münchow, Andreas Access to this item has been restricted by repository administrators at the request of the publisher until June 30, 2016. Close

• 126. [Article] Diel periodicity in ammonium uptake and regeneration in the oceanic subarctic Pacific: Implications for interactions in microbial food webs

  Diel periodicity in NH4+ uptake and regeneration in the nutrient-rich environment of the oceanic subarctic Pacific was examined. Surface water was incubated in large shipboard microcosms that allowed repeated ...

  Citation × Citation Citation Abstract Copy Title: Diel periodicity in ammonium uptake and regeneration in the oceanic subarctic Pacific: Implications for interactions in microbial food webs Author: Kokkinakis, Steven A., Wheeler, Patricia A., Kirchman, David L., Landry, Michael R. Diel periodicity in NH4+ uptake and regeneration in the nutrient-rich environment of the oceanic subarctic Pacific was examined. Surface water was incubated in large shipboard microcosms that allowed repeated sampling of the planktonic community for NH4+ cycling rates, bacterial production rates, and population densities of the dominant autotrophs and heterotrophs. Changes in NH4+ concentrations and isotopic enrichments indicated that regeneration took place exclusively at night. Nitrogen uptake rates and bacterial production were maximal during the day. Abundance of <2 μm autotrophic flagellates reached a maximum at the end of day or beginning of night, whereas abundance of zooflagellates in the <2 μm and 1–10 μm size classes showed a twofold variation with maximal abundances occurring at the beginning of day. These contrasting diel patterns suggest short-term, cyclic disequilibrium in production and grazing within the microbial food web. Hence, analysis of relationships among the various components of microbial populations in this type of environment will require sampling on much shorter time scales than has been attempted in past studies. Title: Diel periodicity in ammonium uptake and regeneration in the oceanic subarctic Pacific: Implications for interactions in microbial food webs Author: Kokkinakis, Steven A., Wheeler, Patricia A., Kirchman, David L., Landry, Michael R. Diel periodicity in NH4+ uptake and regeneration in the nutrient-rich environment of the oceanic subarctic Pacific was examined. Surface water was incubated in large shipboard microcosms that allowed repeated sampling of the planktonic community for NH4+ cycling rates, bacterial production rates, and population densities of the dominant autotrophs and heterotrophs. Changes in NH4+ concentrations and isotopic enrichments indicated that regeneration took place exclusively at night. Nitrogen uptake rates and bacterial production were maximal during the day. Abundance of <2 μm autotrophic flagellates reached a maximum at the end of day or beginning of night, whereas abundance of zooflagellates in the <2 μm and 1–10 μm size classes showed a twofold variation with maximal abundances occurring at the beginning of day. These contrasting diel patterns suggest short-term, cyclic disequilibrium in production and grazing within the microbial food web. Hence, analysis of relationships among the various components of microbial populations in this type of environment will require sampling on much shorter time scales than has been attempted in past studies. Close

• 127. [Article] Ammonium recycling limits nitrate use in the oceanic subarctic Pacific

  Seasonal and diel changes in nutrient concentrations and nitrogen assimilation rates were used to assess the effects of NH4+ on NO3- assimilation. Surface-water NO3- concentrations ranged from 6 to 17 ...

  Citation × Citation Citation Abstract Copy Title: Ammonium recycling limits nitrate use in the oceanic subarctic Pacific Author: Kokkinakis, Steven A., Wheeler, Patricia A. Seasonal and diel changes in nutrient concentrations and nitrogen assimilation rates were used to assess the effects of NH4+ on NO3- assimilation. Surface-water NO3- concentrations ranged from 6 to 17 μM while NH4+ concentrations ranged from 0 to 0.4 μM. Total N assimilation ranged from 84 to 732 nM d–1 but showed no seasonal trend. NH4+ and urea concentrations were < 1% of total dissolved inorganic N, but use of this “regenerated” N still accounted for 44–89% of total N assimilation. Rates of NO3- assimilation were negatively correlated with ambient NH4+ concentrations, and concentrations of NH4+ between 0.1 and 0.3 μM caused complete inhibition of NO3- assimilation. NO3- was more important as a source of N in spring than in summer. We attribute this pattern to a summer increase in turnover rates for NH4+. Turnover times for the dissolved NH4+ pool were half as long in August as in May. Grazing and recycling in the euphotic zone apparently both play significant roles in preventing depletion of NO3- in the oceanic subarctic Pacific. Title: Ammonium recycling limits nitrate use in the oceanic subarctic Pacific Author: Kokkinakis, Steven A., Wheeler, Patricia A. Seasonal and diel changes in nutrient concentrations and nitrogen assimilation rates were used to assess the effects of NH4+ on NO3- assimilation. Surface-water NO3- concentrations ranged from 6 to 17 μM while NH4+ concentrations ranged from 0 to 0.4 μM. Total N assimilation ranged from 84 to 732 nM d–1 but showed no seasonal trend. NH4+ and urea concentrations were < 1% of total dissolved inorganic N, but use of this “regenerated” N still accounted for 44–89% of total N assimilation. Rates of NO3- assimilation were negatively correlated with ambient NH4+ concentrations, and concentrations of NH4+ between 0.1 and 0.3 μM caused complete inhibition of NO3- assimilation. NO3- was more important as a source of N in spring than in summer. We attribute this pattern to a summer increase in turnover rates for NH4+. Turnover times for the dissolved NH4+ pool were half as long in August as in May. Grazing and recycling in the euphotic zone apparently both play significant roles in preventing depletion of NO3- in the oceanic subarctic Pacific. Close

• 128. [Article] Shallow aquifer characteristics adjacent to the upper Middle Fork John Day River, eastern Oregon

  Subsurface inputs into lotic systems are a primary mechanism for cooling streams with high ambient water temperatures. Objectives of this study include: 1) to determine the effectiveness of Forward Looking ...

  Citation × Citation Citation Abstract Copy Title: Shallow aquifer characteristics adjacent to the upper Middle Fork John Day River, eastern Oregon Author: Hopson, Richard G. Subsurface inputs into lotic systems are a primary mechanism for cooling streams with high ambient water temperatures. Objectives of this study include: 1) to determine the effectiveness of Forward Looking Infrared (FLIR) thermal imagery to detect shallow aquifers, 2) to characterize certain physical, spatial, and temporal characteristics of the fluvial, floodplain, and subsurface environments, and 3) to determine if hyporheic water can be distinguished from true groundwater using water quality characteristics. Primary variables include free water surface elevation, temperature, and specific conductivity. Study sites were located within three effluent reaches of the unconstrained, fourth order upper Middle Fork John Day River in eastern Oregon. A significant association was observed between relative ground surface temperature and depth-to-groundwater at the three well fields. In addition, the ability of FLIR to predict shallow aquifers decreased as depth-to-groundwater increased. However, a high degree of variability was observed. Spatial aquifer water surface patterns varied between sites and appear to be influenced by hydrologic origin, including various groundwater, hyporheic water, and irrigation water sources. The net hydrologic flux into the river per meter depth at Well Field 3 was estimated at 4.2E-03 m3/s-m. Diurnal water surface elevation varied among wells and between wells and staff gages. Annual mean aquifer recharge was greatest during fall months while mean discharge occurred only during spring months. Mean annual aquifer temperature varied according to degree of connectivity between surface/subsurface environments. Subsurface aquifer temperature and specific conductivity patterns were not always correlated to water surface gradients. However, these variables may represent subsurface fluxes not apparent using water surface contours. An irrigation effect on aquifer temperature and specific conductivity may have influenced these variables. Mean percent saturation of dissolved oxygen was low in the wells and saturated in the Middle Fork. pH values were generally neutral in the aquifer and slightly alkaline in the Middle Fork. Water surface gradient provided the most reliable indicator of hyporheic water, followed by subsurface temperature and specific conductivity. Boundaries between groundwater, hyporheic water, and irrigation water appeared to exist as a gradient rather than an abrupt edge. However, environmental factors may also have influenced this relationship. Title: Shallow aquifer characteristics adjacent to the upper Middle Fork John Day River, eastern Oregon Author: Hopson, Richard G. Subsurface inputs into lotic systems are a primary mechanism for cooling streams with high ambient water temperatures. Objectives of this study include: 1) to determine the effectiveness of Forward Looking Infrared (FLIR) thermal imagery to detect shallow aquifers, 2) to characterize certain physical, spatial, and temporal characteristics of the fluvial, floodplain, and subsurface environments, and 3) to determine if hyporheic water can be distinguished from true groundwater using water quality characteristics. Primary variables include free water surface elevation, temperature, and specific conductivity. Study sites were located within three effluent reaches of the unconstrained, fourth order upper Middle Fork John Day River in eastern Oregon. A significant association was observed between relative ground surface temperature and depth-to-groundwater at the three well fields. In addition, the ability of FLIR to predict shallow aquifers decreased as depth-to-groundwater increased. However, a high degree of variability was observed. Spatial aquifer water surface patterns varied between sites and appear to be influenced by hydrologic origin, including various groundwater, hyporheic water, and irrigation water sources. The net hydrologic flux into the river per meter depth at Well Field 3 was estimated at 4.2E-03 m3/s-m. Diurnal water surface elevation varied among wells and between wells and staff gages. Annual mean aquifer recharge was greatest during fall months while mean discharge occurred only during spring months. Mean annual aquifer temperature varied according to degree of connectivity between surface/subsurface environments. Subsurface aquifer temperature and specific conductivity patterns were not always correlated to water surface gradients. However, these variables may represent subsurface fluxes not apparent using water surface contours. An irrigation effect on aquifer temperature and specific conductivity may have influenced these variables. Mean percent saturation of dissolved oxygen was low in the wells and saturated in the Middle Fork. pH values were generally neutral in the aquifer and slightly alkaline in the Middle Fork. Water surface gradient provided the most reliable indicator of hyporheic water, followed by subsurface temperature and specific conductivity. Boundaries between groundwater, hyporheic water, and irrigation water appeared to exist as a gradient rather than an abrupt edge. However, environmental factors may also have influenced this relationship. Close

• 129. [Article] Kinetic design of free water surface constructed wetlands for treatment of pulp mill effluent

  Citation × Citation Citation Abstract Copy Title: Kinetic design of free water surface constructed wetlands for treatment of pulp mill effluent Author: Hossain, Belayet Title: Kinetic design of free water surface constructed wetlands for treatment of pulp mill effluent Author: Hossain, Belayet Close

• 130. [Article] Development of baseline data on Oregon's high desert vernal pools

  Vernal pools are ephemeral surface water wetlands with unique hydrology, ecology and species composition. Rare and endemic species rely on vernal pool habitat due to specialization traits the species possess ...

  Citation × Citation Citation Abstract Copy Title: Development of baseline data on Oregon's high desert vernal pools Author: Wyland, Sara Alice Vernal pools are ephemeral surface water wetlands with unique hydrology, ecology and species composition. Rare and endemic species rely on vernal pool habitat due to specialization traits the species possess because they are adapted to the extreme conditions. Many vernal pool basins have been topographically and hydrologically altered and are utilized heavily for cattle, which can lead to deleterious effects to vernal pool ecosystems. Little research has been performed on Oregon's high desert vernal pools, impeding proper management and protection. This study was conducted to gather baseline data on the pools over the 2011 and 2012 spring to fall seasons. Water quality analysis was performed to determine if differences exist between natural vernal pools, those that have been altered, and anthropogenic water source alternatives in the region, and to see if water chemistry changes as the pools dry down. Some trends were shown, but the data were highly variable within site classifications. General temporal trends of pools showed increases in temperature, turbidity, conductivity and anions, and decreases in dissolved oxygen and oxidation-reduction potential throughout the seasons. Natural pools displayed opposite temporal trends of turbidity and nitrate than other site types, indicating different chemical functioning. Excavations inside basins where water was only present in the excavation had different water chemistry from excavations where water was overflowing into the natural basin, and from unaltered natural basins, demonstrating impacts of excavated topography. Although some patterns can be recognized, the data was variable and suggest little can be assumed about the water quality status of Oregon’s high desert vernal pools. A GIS and remote sensing method was developed to quantify the change in water surface area in the high desert at various time points by performing supervised classifications of SPOT images. The method was found to be capable of easily deriving surface areas from the SPOT images, with little potential for error. Water surface areas were extracted from ten SPOT images taken from 2010 to 2013. Surface areas were compared to local climate data to assess for determining factors. The temporal resolution of the preliminary analysis was not high enough to determine causation, but results suggest annual precipitation and timing persistence are important factors in water surface areas. Title: Development of baseline data on Oregon's high desert vernal pools Author: Wyland, Sara Alice Vernal pools are ephemeral surface water wetlands with unique hydrology, ecology and species composition. Rare and endemic species rely on vernal pool habitat due to specialization traits the species possess because they are adapted to the extreme conditions. Many vernal pool basins have been topographically and hydrologically altered and are utilized heavily for cattle, which can lead to deleterious effects to vernal pool ecosystems. Little research has been performed on Oregon's high desert vernal pools, impeding proper management and protection. This study was conducted to gather baseline data on the pools over the 2011 and 2012 spring to fall seasons. Water quality analysis was performed to determine if differences exist between natural vernal pools, those that have been altered, and anthropogenic water source alternatives in the region, and to see if water chemistry changes as the pools dry down. Some trends were shown, but the data were highly variable within site classifications. General temporal trends of pools showed increases in temperature, turbidity, conductivity and anions, and decreases in dissolved oxygen and oxidation-reduction potential throughout the seasons. Natural pools displayed opposite temporal trends of turbidity and nitrate than other site types, indicating different chemical functioning. Excavations inside basins where water was only present in the excavation had different water chemistry from excavations where water was overflowing into the natural basin, and from unaltered natural basins, demonstrating impacts of excavated topography. Although some patterns can be recognized, the data was variable and suggest little can be assumed about the water quality status of Oregon’s high desert vernal pools. A GIS and remote sensing method was developed to quantify the change in water surface area in the high desert at various time points by performing supervised classifications of SPOT images. The method was found to be capable of easily deriving surface areas from the SPOT images, with little potential for error. Water surface areas were extracted from ten SPOT images taken from 2010 to 2013. Surface areas were compared to local climate data to assess for determining factors. The temporal resolution of the preliminary analysis was not high enough to determine causation, but results suggest annual precipitation and timing persistence are important factors in water surface areas. Close