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Full-Text Articles in Physical Sciences and Mathematics
Sediment Nutrient Dynamics In Fondriest Agricultural Settling Pond, Marie Grace Bezold
Sediment Nutrient Dynamics In Fondriest Agricultural Settling Pond, Marie Grace Bezold
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Excess loading of nitrogen (N) and phosphorus (P) is a serious global problem and has numerous negative impacts on water quality of aquatic ecosystems including eutrophication, harmful algal blooms, and hypoxia. Anthropogenic activities (such as the Haber-Bosch process, burning of fossil fuels, sewage treatment, and manure reuse) have led to excess N loading to aquatic systems. Sediment N dynamics were examined from Oct 2019 – Oct 2020 in an agricultural settling pond connected to a constructed wetland adjacent to an agricultural field. Intact sediment cores were amended with 15N for continuous-flow incubations to measure denitrification and N fixation rates, as …
Internal Loading Of Nitrogen (N) And Phosphorus (P), Reduced N Forms, And Periodic Mixing Support Cyanobacterial Harmful Algal Blooms (Habs) In Shallow, Eutrophic Honeoye Lake (New York, Usa), Justin Adam Myers
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Cyanobacteria are important primary producers, but large cyanobacterial harmful algal blooms (HABs) have many negative ecological and health impacts and are becoming increasingly common. Honeoye Lake (New York, USA) is a shallow, eutrophic lake characterized by increasingly frequent HABs. Nitrogen (N) and phosphorus (P) loads often drive HABs in lakes, and sediment processes can contribute to N removal (e.g., denitrification) or loading (e.g., N fixation, remineralization). Sediment cores and lake water were collected during May–October (2016–2018) at two sites and incubated with no amendments (controls) or 15N stable isotopes to measure sediment nutrient fluxes and N cycling dynamics in Honeoye …
Evaluating Sediments As An Ecosystem Service In Western Lake Erie Through Quantification Of Nitrogen Cycling Pathways, Ashlynn Rose Boedecker
Evaluating Sediments As An Ecosystem Service In Western Lake Erie Through Quantification Of Nitrogen Cycling Pathways, Ashlynn Rose Boedecker
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Lake Erie experiences annual cyanobacterial harmful algal blooms (HABs), comprised mostly of non-nitrogen-fixing Microcystis, due to excess nitrogen (N) and phosphorus (P) inputs (eutrophication). Lake Erie's watershed is mostly agricultural, and fertilizers, manure, and drainage practices contribute to high nutrient loads. This study aimed to clarify the role of Lake Erie sediments in either exacerbating or mitigating conditions that fuel HABs via recycling and/or removal, respectively, of excess N and P. Sediment-water interface N dynamics were evaluated in low HAB (2016, dry) and high HAB (2017, wet spring and early summer) years. Intact sediment cores and overlying water were collected …
Methylmercury Bioaccumulation In Spotted Salamanders (Ambystoma Maculatum) In Southern Ohio, Rachel Alex Walker
Methylmercury Bioaccumulation In Spotted Salamanders (Ambystoma Maculatum) In Southern Ohio, Rachel Alex Walker
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Mercury (Hg) is a volatile element increasing in concentration in the environment as a result of anthropogenic emissions. Microorganisms can transform mercury into monomethylmercury (MMHg), the form of Hg that bioaccumulates, biomagnifies, and can harm humans and wildlife. Most studies of MMHg bioaccumulation in wildlife have focused on aquatic organisms due to consumption of fish being the primary route of human exposure to MMHg. However, organisms in terrestrial ecosystems also are exposed to MMHg that may impact ecosystem biodiversity, food-web dynamics, and organisms and ecosystem health. I investigated bioaccumulation and maternal transfer of MMHg in spotted salamanders (Ambystoma maculatum) captured …
The Biogeochemistry Of Carbon Isotopes In Local Lakes, Stephen Edward Sadurski
The Biogeochemistry Of Carbon Isotopes In Local Lakes, Stephen Edward Sadurski
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Photosynthesis, respiration, and decay of organic matter all involve the transfer of carbon among the carbon-bearing species in the systems. These biogeochemical processes also fractionate the carbon isotope composition, which results in changes to the carbon isotope composition of the dissolved inorganic carbon (DIC) pool. This thesis presents two separate, but related studies regarding the influence of biogeochemical processes on carbon isotopes in local lakes. Crystal Lake is a small but deep glacial lake (12.5 acres, 11.9 meters). The study shows that during thermal stratification, the heaviest carbon can be found in the epilimnion near the surface, where photosynthesis dominates …