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Full-Text Articles in Life Sciences

Quantifying How Coastal Flooding And Stormwater Runoff Drive Spatiotemporal Variability In Carbon And Nutrient Processing In Urban Aquatic Ecosystems, Matthew A. Smith Oct 2021

Quantifying How Coastal Flooding And Stormwater Runoff Drive Spatiotemporal Variability In Carbon And Nutrient Processing In Urban Aquatic Ecosystems, Matthew A. Smith

FIU Electronic Theses and Dissertations

Coastal river networks alter the transport and transformation of dissolved organic carbon (DOC) and dissolved organic matter (DOM), which can vary in concentration and composition across spatiotemporal scales. Given climate-induced shifts in rainfall and tidal variation in low-lying coastal regions, there is an increasing need to quantify effects of flooding on biogeochemical cycling. Specifically, urban flooding is becoming increasingly common due to biophysical alterations to hydrology from urbanization and climate change. Urban ecosystems have been characterized as having a distinct biogeochemistry compared to other systems, largely due to increased frequency and magnitude of riverine and coastal flooding. Consequently, the role …


Hydrologic Controls On Phosphorus Speciation And Mobilization In A Subalpine Watershed (East River, Colorado), Lucia Isobel Arthen-Long Oct 2021

Hydrologic Controls On Phosphorus Speciation And Mobilization In A Subalpine Watershed (East River, Colorado), Lucia Isobel Arthen-Long

Masters Theses

The cycling of phosphorus (P) through floodplain environments is critical to ecosystem productivity and has significant implications on both water quality and soil fertility. P export from soils in response to saturation has been well documented, but the relative vulnerability of specific P pools to mobilization remains poorly constrained, as do the mechanisms mediating its release. The prediction of P availability in and export from mountainous floodplain soils is of great importance as global climate change is projected to significantly alter precipitation regimes in alpine systems. This study combined a thorough characterization of P distribution across a hillslope to floodplain …


Net Geochemical Release Of Base Cations From 25 Forested Watersheds In The Catskill Region Of New York, Sara C. Nieman, Chris E. Johnson Jul 2021

Net Geochemical Release Of Base Cations From 25 Forested Watersheds In The Catskill Region Of New York, Sara C. Nieman, Chris E. Johnson

Civil and Environmental Engineering

Chemical weathering of minerals is the principal mechanism by which base cations (Ca2+, Mg2+, K+, and Na+) are released and acidity is neutralized in soils, bedrock and drainage waters. Quantifying the release of base cations from watershed soils is therefore crucial for the calculation of “critical loads” of atmospheric acidity to forest ecosystems. We used a mass-balance approach to estimate the rate of release of base cations in 25 headwater catchments in the Catskill region of New York, an area historically subject to high inputs of acid deposition. In 2010-2013, total net …


In-Depth Analysis Of N2o Fluxes In Tropical Forest Soils Of The Congo Basin Combining Isotope And Functional Gene Analysis, Nora Gallarotti, Matti Barthel, Elizabeth Verhoeven, Engil Isadora Pujol Pereira, Marijn Bauters, Simon Baumgartner, Travis W. Drake, Pascal Boeckx, Joachim Mohn, Manon Longepierre May 2021

In-Depth Analysis Of N2o Fluxes In Tropical Forest Soils Of The Congo Basin Combining Isotope And Functional Gene Analysis, Nora Gallarotti, Matti Barthel, Elizabeth Verhoeven, Engil Isadora Pujol Pereira, Marijn Bauters, Simon Baumgartner, Travis W. Drake, Pascal Boeckx, Joachim Mohn, Manon Longepierre

School of Earth, Environmental, and Marine Sciences Faculty Publications and Presentations

Primary tropical forests generally exhibit large gaseous nitrogen (N) losses, occurring as nitric oxide (NO), nitrous oxide (N2O) or elemental nitrogen (N2). The release of N2O is of particular concern due to its high global warming potential and destruction of stratospheric ozone. Tropical forest soils are predicted to be among the largest natural sources of N2O; however, despite being the world’s second-largest rainforest, measurements of gaseous N-losses from forest soils of the Congo Basin are scarce. In addition, long-term studies investigating N2O fluxes from different forest ecosystem types (lowland and montane forests) are scarce. In this study we show that …


The Quantitative Assessment Of Pond Scum: An Examination Of The Biogeochemistry Of Phosphorus Cycling In The Belgrade Lakes, Abbey M. Sykes Jan 2021

The Quantitative Assessment Of Pond Scum: An Examination Of The Biogeochemistry Of Phosphorus Cycling In The Belgrade Lakes, Abbey M. Sykes

Honors Theses

The internal recycling phosphorus in freshwater lake bottom sediments represents a significant source of hypolimnetic phosphorus (P) release for many of Maine’s lakes. In summer months, Maine lakes often thermally stratify and the lake hypolimnion develops anoxia, leading to a reduction in redox potential at the sediment-water interface. These reducing conditions facilitate the reductive dissolution of ferric iron, and, since phosphorus is often present in freshwater lake sediments as solid FeOOH-PO4 complexes, results in release of soluble phosphorus into the water column. Our current study presents field and laboratory data from sediment fractionation extractions designed to quantify concentrations of …


Nitrogen Dynamics And Transport Along Flowpaths In A Rural Wetland-Stream Complex, Colton Kyro Jan 2021

Nitrogen Dynamics And Transport Along Flowpaths In A Rural Wetland-Stream Complex, Colton Kyro

Graduate Student Theses, Dissertations, & Professional Papers

Human activities have doubled the rate of nitrogen inputs onto the landscape resulting in elevated nitrogen concentrations in our streams. Anthropogenically applied nitrogen is largely transported to stream networks via groundwater movement. Groundwater discharge occurs in distinct points along a stream but whose influences can often persist far beyond that area due to insufficient biogeochemical removal of imported nitrogen potentially causing alterations in community structure and precipitating large algae blooms. To understand the factors governing nitrogen abundance in a historical polluted stream, I used a mass-balance approach to quantify groundwater-surface water interaction and the magnitude of groundwater nitrogen input and …