A5091489961- Water Quality and Pollution Assessment
- Marine and coastal ecosystems
- Aquatic Ecosystems and Phytoplankton Dynamics
- Soil and Water Nutrient Dynamics
- Water Quality Monitoring and Analysis
- Water Quality and Resources Studies
- Mine drainage and remediation techniques
- Heavy metals in environment
- Groundwater and Isotope Geochemistry
- Fish Ecology and Management Studies
- Mercury impact and mitigation studies
- Atmospheric and Environmental Gas Dynamics
- Environmental Toxicology and Ecotoxicology
- Aquatic Invertebrate Ecology and Behavior
- Wastewater Treatment and Nitrogen Removal
- Toxic Organic Pollutants Impact
- Hydrology and Watershed Management Studies
- Groundwater flow and contamination studies
- Remote Sensing in Agriculture
- Water resources management and optimization
- Peatlands and Wetlands Ecology
- Water Quality Monitoring Technologies
- Analytical Chemistry and Sensors
- Isotope Analysis in Ecology
- Land Use and Ecosystem Services
University of Minnesota
2014-2024
University of Florida
1975-2013
Minnesota Department of Natural Resources
1999-2007
U.S. National Science Foundation
2005-2006
Twin Cities Orthopedics
1998-2006
University of Illinois Chicago
2006
Science Museum of Minnesota
2004
Pioneer (United States)
1994
University of California, Los Angeles
1981-1982
Metropolitan State University
1982
Mercury contamination of remote lakes has been attributed to increasing deposition atmospheric mercury, yet historic rates and inputs from terrestrial sources are essentially unknown. Sediments seven headwater in Minnesota Wisconsin were used reconstruct regional modern preindustrial mercury. Whole-basin mercury fluxes, determined lake-wide arrays dated cores, indicate that the annual increased 3.7 12.5 micrograms per square meter since 1850 25 percent catchment is exported lake. The...
The importance of the principal natural scavenging agents for hydroxyl radicals (•OH) was evaluated, and a general framework developed to predict significance nitrate-induced, •OH-mediated degradation aquatic contaminants. Rate constants •OH by dissolved organic matter (DOM) from five surface water sources were in narrow range (2.3 ± 0.77 × 104 (mg C/L)-1 s-1), which is similar previously reported values suggests that DOM as sink can be estimated simply carbon (DOC) concentration water....
ABSTRACT : A data base consisting of predominantly nitrogen limited Florida lakes from the National Eutrophication Survey (NES) was used to develop a trophic state index based on total concentration. This compared with Carlson's (1977) phosphorus concentration, and lesser two values for each lake averaged indices Secchi disk transparency chlorophyll concentration assess 40 NES lakes.
Abstract Ground-based measurements on 15 Minnesota lakes with wide ranges of optical properties and Landsat TM data from the same were used to evaluate effect humic color satellite-inferred water quality conditions. Color (C440), as measured by absorbance at 440 nm, causes only small biases in estimates Secchi disk transparency (SDT) data, except very high values (> ~ 300 chloroplatinate units, CPU). Similarly, when chlorophyll a (chl a) levels are moderate or 10 μg/L), low-to-moderate have...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTOxygen consumption in humic-colored waters by a photochemical ferrous-ferric catalytic cycleCarl J. Miles and Patrick L. BrezonikCite this: Environ. Sci. Technol. 1981, 15, 9, 1089–1095Publication Date (Print):September 1, 1981Publication History Published online1 May 2002Published inissue 1 September 1981https://pubs.acs.org/doi/10.1021/es00091a010https://doi.org/10.1021/es00091a010research-articleACS PublicationsRequest reuse permissionsArticle...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMeasurement and significance of adenosine triphosphate in activated sludgeJames W. Patterson, Patrick L. Brezonik, Hugh D. PutnamCite this: Environ. Sci. Technol. 1970, 4, 7, 569–575Publication Date (Print):July 1, 1970Publication History Published online1 May 2002Published inissue 1 July 1970https://doi.org/10.1021/es60042a003RIGHTS & PERMISSIONSArticle Views229Altmetric-Citations99LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant...
This study evaluates currently available imagery from Landsat, MERIS, MODIS, and AWiFS sensors for their usefulness in regional‐scale measurements of lake water clarity chlorophyll comprehensive management scientific studies (e.g., modeling). Images these systems were collected nearly concurrently processed using methods similar to those developed previously regional assessments Landsat imagery. We tested both atmospherically corrected uncorrected products; the products performed as well or...
Distribution coefficients (KOC) for Hg2+ binding by IHSS Pahokee peat humic acid (PHA) and acids separated from O-horizons peats in a northern temperate forest were determined using competitive ligand-exchange method. All measurements made at low ratios of added to reduced S. The commonly used chelating agents, EGTA DTPA, found be ineffective ligands; thus, we dl-penicillamine, synthetic amino with thiol group. Calculated free [Hg2+] equilibrium is very low, ranging 10-26.4 pH 1.9 10-36.9...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTDentrification as a nitrogen sink in Lake Mendota, WisconsinPatrick L. Brezonik and George Fred LeeCite this: Environ. Sci. Technol. 1968, 2, 120–125Publication Date (Print):February 1, 1968Publication History Published online1 May 2002Published inissue 1 February 1968https://pubs.acs.org/doi/10.1021/es60014a003https://doi.org/10.1021/es60014a003research-articleACS PublicationsRequest reuse permissionsArticle Views202Altmetric-Citations64LEARN...
Abstract Secchi depth (SD), a primary metric to assess trophic state, is controlled in many lakes by algal densities, measured as chlorophyll‐ (chl‐ ) concentration. Two other optically related water quality variables also directly affect SD : non‐algal suspended solids ( SS NA and colored dissolved organic matter CDOM , expressed the absorption coefficient at 440 nm, ). Using database of ~1,460 samples from ~625 inland lake basins Minnesota two Upper Midwest states, Wisconsin Michigan, we...
Absorption of solar radiation by colored dissolved organic matter (CDOM) in surface waters results the formation photochemically produced reactive intermediates (PPRIs) that react with pollutants water. Knowing steady-state concentrations PPRIs ([PPRI]ss) is critical to predicting persistence sunlit waters. CDOM levels (a440) can be measured remotely for lakes over large areas using satellite imagery. Laboratory measurements [PPRI]ss and apparent quantum yields (Φ) three (3DOM*, 1O2, •OH)...
Synopsis In experiments lakes 223 (L223) and 302 South (L302S) in the Experimental Lakes Area north-western Ontario, Little Rock Lake (LRL) northern Wisconsin, were progressively acidified with sulphuric acid from original pH values of 6.1–6.8 to 4.7–5.1. Although at different locations physical settings assemblages plants animals including fish, there remarkable similarities their responses, particularly regard biogeochemical processes effects on biota lower trophic levels. All three...
Rates of sulfate diffusion and reduction were measured in sediments Little Rock Lake, an oligotrophic, soft‐water lake northern Wisconsin. Laboratory measurements kinetics found half‐saturation constants (20–30 µ mol liter −1 ) Q 10 values (2.6) similar to reported the literature. Sulfate under situ conditions sediment cores was limited by followed uptake as laboratory experiments. Some variation kinetic parameters evident a function location lake. No seasonal observed rates sediments,...
Abstract Light reflected from lake surfaces can convey much information about water quality, especially algal abundance, humic content, turbidity and suspended solids. reflectance lakes is complicated, detailed spectra are needed for analysis of controlling factors. We obtained the 15 in east-central Minnesota found patterns related to chlorophyll a (chl a), matter (colored dissolved organic matter, CDOM). Increasing chl generally resulted higher across visible near-infrared spectrum. CDOM...