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Full-Text Articles in Earth Sciences
Labile Dissolved Nickel (Ni) Concentrations In The North Pacific, Calyn M. Crawford
Labile Dissolved Nickel (Ni) Concentrations In The North Pacific, Calyn M. Crawford
USF Tampa Graduate Theses and Dissertations
Nickel (Ni) is an important micronutrient for phytoplankton and bacteria that serves as a required co-factor in several metalloenzymes. Despite these known biological uses, total dissolved Ni concentrations remain elevated in global surface waters, in contrast to the surface depletion commonly observed for macronutrients and other nutrient-type trace elements. A prevailing hypothesis for the muted depletion of dissolved Ni concentrations in surface waters is that dissolved Ni in seawater is not in a bioavailable form. The chemical lability of Ni in seawater provides insight into Ni speciation and bioavailability, but few measurements have been made in the open ocean to …
A Process-Based Approach To Evaluating The Role Of Organic Ligands In Trace Metal Cycling In The Marine Environment, Travis Mellett
A Process-Based Approach To Evaluating The Role Of Organic Ligands In Trace Metal Cycling In The Marine Environment, Travis Mellett
USF Tampa Graduate Theses and Dissertations
In addition to control by major nutrient elements (nitrogen, phosphorous, and silicon) growth and community composition of marine phytoplankton is also regulated by trace element nutrients (iron, copper, manganese, zinc, cobalt, nickel, and cadmium). Of these, iron is the most influential in the modern ocean, regulating phytoplankton growth and carbon export in high-nutrient low-chlorophyll regimes and exerting an important control on the marine nitrogen cycle through its role in di-nitrogen fixation. The distributions of these metals has the capacity to control primary production and phytoplankton community composition through differences in cellular quotas or metal sensitivities amongst species. The relationship between …
Marsh-Exported Dissolved Organic Matter Fate In Estuaries, Laura Ann Logozzo
Marsh-Exported Dissolved Organic Matter Fate In Estuaries, Laura Ann Logozzo
Dissertations and Theses
Dissolved organic matter (DOM) is a significant driver of estuarine productivity and nutrient cycling. The colored component of DOM, chromophoric dissolved organic matter (CDOM), impacts coastal optical properties, ocean color, and light attenuation. While marshes are largely considered sinks for carbon due to their high productivity and low soil carbon degradation rates, laterally they are sources of carbon as optically and chemically distinct DOM to surrounding aquatic ecosystems; these inputs are often essential in sustaining a net heterotrophic system. However, the photoreactivity and bioavailability of marsh-exported DOM is largely uncategorized, thus making it difficult to quantify its impacts on estuarine …
Optical Properties And Bioavailability Of Dissolved Organic Matter Along A Flow-Path Continuum From Soil Pore Waters To The Kolyma River Mainstem, East Siberia, Karen E. Frey, William V. Sobczak, Paul J. Mann, Robert M. Holmes
Optical Properties And Bioavailability Of Dissolved Organic Matter Along A Flow-Path Continuum From Soil Pore Waters To The Kolyma River Mainstem, East Siberia, Karen E. Frey, William V. Sobczak, Paul J. Mann, Robert M. Holmes
Geography
The Kolyma River in northeast Siberia is among the six largest Arctic rivers and drains a region underlain by vast deposits of Holocene-aged peat and Pleistocene-aged loess known as yedoma, most of which is currently stored in ice-rich permafrost throughout the region. These peat and yedoma deposits are important sources of dissolved organic matter (DOM) to inland waters that in turn play a significant role in the transport and ultimate remineralization of organic carbon to CO2 and CH4 along the terrestrial flow-path continuum. The turnover and fate of terrigenous DOM during offshore transport largely depends upon the composition and amount …
Classification Of Explosives Transformation Products In Plant Tissue, Steven L. Larson, Robert P. Jones, Lynn Escalon, Don Parker
Classification Of Explosives Transformation Products In Plant Tissue, Steven L. Larson, Robert P. Jones, Lynn Escalon, Don Parker
US Army Corps of Engineers
Explosives contamination in surface or groundwater used for the irrigation of food crops and phytoremediation of explosives-contaminated soil or water using plant-assisted biodegradation have brought about concerns as to the fate of explosives in plants. Liquid scintillation counting, high-performance liquid chromatography, and gel permeation chromatography were utilized to characterize explosives (hexahydro-1,3,5-trinitro-1,3,5-triazine and trinitrotoluene) and their metabolites in plant tissues obtained from three separate studies. Analyzing tissues of yellow nutsedge (Cyperus esculentus), corn (Zea mays), lettuce (Lacuta sativa), tomato (Lyopersicum esculentum), radish (Raphanus sativus), and parrot feather (Myriophyllum aquaticum) …