A5089339958- Marine and coastal ecosystems
- Marine Biology and Ecology Research
- Marine and fisheries research
- Coastal wetland ecosystem dynamics
- Mercury impact and mitigation studies
- Marine Bivalve and Aquaculture Studies
- Water Quality and Resources Studies
- Soil and Water Nutrient Dynamics
- Marine and coastal plant biology
- Toxic Organic Pollutants Impact
- Wastewater Treatment and Nitrogen Removal
- Isotope Analysis in Ecology
- Water Quality Monitoring and Analysis
- Microbial Community Ecology and Physiology
- Air Quality and Health Impacts
- Water Quality and Pollution Assessment
- Heavy metals in environment
- Water Quality Monitoring Technologies
- Coral and Marine Ecosystems Studies
- Aquatic Ecosystems and Phytoplankton Dynamics
- Coastal and Marine Dynamics
- Coastal and Marine Management
- Vibrio bacteria research studies
- Heavy Metal Exposure and Toxicity
- Fecal contamination and water quality
University of West Florida
2013-2023
United States Geological Survey
1993-1995
Aarhus University
1991
University of Maryland Center for Environmental Science
1988-1990
University of Maryland, College Park
1986
Contemporaneous measurements are reported for nitrification, denitrification, and net sediment— water fluxes of NH 4 + NO 3 − in the mesohaline region Chesapeake Bay. Seasonal cycles over a 2‐yr period were characterized by midsummer maximum efflux to overlying May peak removal from sediments. Coherent temporal patterns nitrification denitrification observed, with relatively high values spring fall virtual elimination both processes summer. Indirect indicate that was limited shallow O 2...
The effects of organic additions on nitrification and dentrification were examined in sediment microcosms. material, heat killed yeast, had a C/N ratio 7.5 was added to sieved, homogenized sediments. Four treatments compared: no addition (control), 30 g dry weight (dw) m−2 mixed throughout the 10 cm column (30M), 100 dw sediments (100M), into top 1 (100S). After microcosms been established for 7–11 days, depth O2 penetration, sediment-water fluxes rates measured. Nitrification measured using...
Measurements of primary production and respiration provide fundamental information about the trophic status aquatic ecosystems, yet such measurements are logistically difficult expensive to sustain as part long-term monitoring programs. However, ecosystem metabolism parameters can be inferred from high frequency water quality data collections using autonomous logging instruments. For this study, we analyzed time series datasets three Gulf Mexico estuaries: Grand Bay, MS; Weeks AL;...
Mercury (Hg) wet deposition, transfer from the atmosphere to Earth's surface by precipitation, in United States is highest locations and seasons with frequent deep convective thunderstorms, but it has never been demonstrated whether connection causal or simple coincidence. We use rainwater samples over 800 individual precipitation events show that thunderstorms increase Hg concentrations 50% relative weak stratiform of equal depth. Radar satellite observations reveal strong convection...
Increased organic loading to sediments from eutrophication often results in hypoxia, reduced nitrification and increased production of hydrogen sulfide, altering the balance between nitrogen removal retention. We examined effect short-term exposure various oxygen sulfide concentrations on sediment nitrification, denitrification DNRA a chronically hypoxic basin Roskilde Fjord, Denmark. Surprisingly, rates were highest anoxic treatments (about 5 μmol cm−3 d−1) high treatment was not...
Abstract. In an effort to understand and quantify the impact of local, regional, far-distant atmospheric mercury sources rainfall deposition in Pensacola, Florida watershed, a program event-based sampling was started late 2004. Modified Aerochem-Metrics wet/dry samplers were deployed at three sites region around Crist coal-fired power plant samples collected continuously for years. Samples analyzed total Hg suite trace elements including Al, As, Ba, Bi, Cd, Ce, Co, Cr, Cs, Cu, Fe, Ga, La,...
Abstract. Atmospheric deposition was measured at three sites in the Pensacola Bay watershed, Florida, between November 2004 and December 2007. Mercury watershed similar to that from nearby Deposition Network along Northern Gulf of Mexico coast. during summer months is higher than other due concentrations rainfall throughout region. constituents like H+, sulfate, nitrate, ammonium, chloride sodium, were much National Program (NADP) sites. Chloride sodium are because closer which a source sea...