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Full-Text Articles in Oceanography and Atmospheric Sciences and Meteorology
Investigating The Relationship Between Dissolved Oxygen And Nitrate Concentration As A Proxy For Marine Ecosystem Health, Natalia M. Moore
Investigating The Relationship Between Dissolved Oxygen And Nitrate Concentration As A Proxy For Marine Ecosystem Health, Natalia M. Moore
Theses and Dissertations
Coastal environments such as seagrass meadows span a wide range of spatial scales and can experience disturbances that cause rapid shifts to ecosystem dynamics. Increased pressure to the coastal zone has highlighted the need for constant, real-time monitoring to monitor current ecosystem status. A custom, low cost, high resolution, in situ sensor network was designed and tested in the Lower Laguna Madre, Texas to characterize primary productivity in seagrass meadows through gradient patterns of dissolved oxygen concentration, with the purpose of determining whether seagrass or phytoplankton were the more dominant primary producer. There was a distinct vertical and horizontal gradient …
Phytoplankton Mortality In An Urban Pond: Understanding The Roles Of Abiotic Factors, Grazing Pressure And Allelopathy, Lauren J. Simmons
Phytoplankton Mortality In An Urban Pond: Understanding The Roles Of Abiotic Factors, Grazing Pressure And Allelopathy, Lauren J. Simmons
Theses and Dissertations
Phytoplankton are found in dynamic aquatic environments, subjected to variations in abiotic (i.e., light, temperature, nutrients) and biotic (i.e., grazing, species interactions) conditions. Phytoplankton responses to these environmental variations are typically observed as changes in chlorophyll a (a surrogate for biomass), but such measurements do not provide information about individual taxa and cannot provide information about cell condition, for example, whether phytoplankton are living or dead. Furthermore, in examining the dynamics of phytoplankton, emphasis is placed on growth, but consideration of loss processes is usually limited to grazing and sedimentation, and not cell death The present study examined cell death …
Phytoplankton Life History Events: Resting Stages And Physiological Cell Death, Christine R. Kozik
Phytoplankton Life History Events: Resting Stages And Physiological Cell Death, Christine R. Kozik
Theses and Dissertations
Understanding and predicting changes in phytoplankton populations requires knowledge of key life history processes such as recruitment from benthic resting stages and losses due to sedimentation and cell death. Currently, these processes are poorly understood in freshwater systems. Phytoplankton resting stage and cell death life history events were separately examined in two freshwater systems in Wisconsin, four northern lakes and an urban pond. In the norther lakes, sedimentation and benthic recruitment were examined using sediment and recruitment traps that were sampled weekly over two summers. Sedimentation and benthic recruitment contributed little to changes in standing crop chl a, but rather …
Freshwater Phytoplankton Populations Detected Using High Pressure Liquid Chromatography (Hplc) Of Taxon-Specific Pigments, Lauren Jeanne Simmons
Freshwater Phytoplankton Populations Detected Using High Pressure Liquid Chromatography (Hplc) Of Taxon-Specific Pigments, Lauren Jeanne Simmons
Theses and Dissertations
Phytoplankton are key primary producers in aquatic ecosystems, and the principle food source for primary consumers. Individual phytoplankton species respond to different physical, chemical and biological parameters, so monitoring taxonomic composition of the phytoplankton community is a means to monitor changes in environmental conditions. Phytoplankton community changes have frequently been monitored by estimating biomass (using chlorophyll a, measured fluorometrically), and taxonomic data obtained from cell counts. While such methods are useful, they are time-consuming. I hypothesized that high pressure liquid chromatography (HPLC) methods, which have been frequently used in marine systems, would allow separation and identification of key pigments. …