A5082888864- Aquatic Ecosystems and Phytoplankton Dynamics
- Marine and coastal ecosystems
- Fish Ecology and Management Studies
- Aquatic Invertebrate Ecology and Behavior
- Heavy metals in environment
- Water Quality and Pollution Assessment
- Soil and Water Nutrient Dynamics
- Environmental Toxicology and Ecotoxicology
- Mercury impact and mitigation studies
- Microbial Community Ecology and Physiology
- Isotope Analysis in Ecology
- Thallium and Germanium Studies
- bioluminescence and chemiluminescence research
- Analytical chemistry methods development
- Radioactive element chemistry and processing
- Geology and Paleoclimatology Research
- Coastal wetland ecosystem dynamics
- Diatoms and Algae Research
- Hydrology and Watershed Management Studies
- Environmental DNA in Biodiversity Studies
- Mine drainage and remediation techniques
- Advanced oxidation water treatment
- Arctic and Antarctic ice dynamics
- Hydrology and Sediment Transport Processes
- Geochemistry and Elemental Analysis
Clarkson University
2014-2025
Algoma University
2024-2025
Syracuse University
2009
SUNY College of Environmental Science and Forestry
2005
University of Toledo
2005
University of Tennessee at Knoxville
2005
Toronto Metropolitan University
2001-2004
Stony Brook University
2003
Woods Hole Oceanographic Institution
2002
Institut National de la Recherche Scientifique
1992-1999
In August of 2003 and 2004, blooms potentially toxic cyanobacteria Microcystis spp. persisted in western Lake Erie. Samples collected from the bloom were analyzed for cyanobacterial toxin microcystin presence cells. Estimates toxicity exceeding 1 μg L-1 (microcystin−LR activity equivalents), safety limit set by World Health Organization, found samples both 2004. The water was confirmed through standard polymerase chain reaction (PCR) using a combination four primer sets. Quantification...
Large lakes of the world are habitats for diverse species, including endemic taxa, and valuable resources that provide humanity with many ecosystem services. They also sentinels global local change, recent studies in limnology paleolimnology have demonstrated disturbing evidence their collective degradation terms depletion (water food), rapid warming loss ice, destruction ecosystems, accelerating pollution. particularly exposed to anthropogenic climatic stressors. The Second Warning Humanity...
Des substances humiques de reference (acides fulviques et humiques) ont ete utilisees pour mettre en evidence l'adsorption la matiere organique dissoute naturelle (MOD) sur des surfaces biologiques. Les experiences realisees a valeurs pH (4-7) concentrations MOD (0-20 mg.L -1 ) representatives celles rencontrees dans le milieu naturel, forces ioniques entre 0,02 0,1 M. Comme modeles biologiques nous avons employe cellules phytoplanctoniques (Chlorella pyrenoidosa, Synechococcus leopoliensis)...
Three nutrient enrichment experiments involving the addition and removal of iron (Fe) alone, as well in combination with phosphorus (P) and/or nitrogen (N), were conducted offshore nearshore waters eastern basin Lake Erie. Erie phytoplankton are at times colimited by P, N, Fe. This was most clearly demonstrated offshore, strongly stratified waters, where Fe concentration below detection (DL = 2.0 nmol L −1 ), limitation indicators (APA, P debt, C: N: N N) indicated strong moderate...
Abstract Among its many impacts, climate warming is leading to increasing winter air temperatures, decreasing ice cover extent, and changing precipitation patterns over the Laurentian Great Lakes their watershed. Understanding predicting consequences of these changes impeded by a shortage winter‐period studies on most aspects Lake limnology. In this review, we summarize what known about during 3–6 months identify key open questions physics, chemistry, biology other large, seasonally frozen...
Biotic and abiotic materials attachment to suspended particulate matter in aquatic systems can increase their toxicity health impacts has led an increased need for consistent sampling across various compartments. Sedimentation traps continuous flow centrifuges are the traditional tools matter, while manta trawls have been widely used surface water of or floating microplastics. Limitations, however, exist cost infrastructure needed deploy such devices. Here we report on construction usage a...
Carbon and nutrient cycles in large temperate lakes such as Lake Erie are primarily driven by phototrophic heterotrophic microorganisms, although our understanding of these is often constrained to late spring through summer due logistical constraints. During periods > 90% ice cover February 2008, 2009, 2010, we collected samples from an icebreaker for examination bacterial production well microbial community structure. In comparison with months (August 2002 2010), tested hypotheses...
Mid-winter limnological surveys of Lake Erie captured extremes in ice extent ranging from expansive cover 2010 and 2011 to nearly ice-free waters 2012. Consistent with a warming climate, on the Great Lakes is decline, thus condition encountered may foreshadow lakes future winter state. Here, we show that pronounced changes annual are accompanied by equally important shifts phytoplankton bacterial community structure. Expansive supported blooms filamentous diatoms. By comparison, free...
The free-ion model of trace metal interactions with aquatic microorganisms states that the biological response to a is proportional activity {Mz+} in solution. applicability model, as it applied toxicity aluminum green alga Chlorella pyrenoidosa presence soil fulvic acid (SFA), was tested defined media (pH 5) designed limit Al algae and SFA. Toxicity not Al3+, an apparent failing model. Fulvic adsorbed cell surfaces (17 mg m-2, pH increased membrane permeability (as measured [14C]sorbitol)...
The diffusion gradient in thin-film hydrogel (DGT) probe is a promising tool for metal speciation work. Based on passive sampling principle, it provides the potential large data sets complex regimes. DGT probes were deployed waters characterized independently using competitive ligand exchange−adsorptive cathodic stripping voltammetry (CLE-ACSV). CLE-ACSV used benzoyl acetone as discrete water samples collected during deployment of probes. 15% polyacrylamide/0.4% bis-acrylamide cross-linker...
Thallium is a toxic metal that of emerging concern in the Great Lakes. It can exist as either Tl(I) or Tl(III), and its oxidation state affects complexation subsequent bioavailability toxicity. We conducted lab field incubations with 204Tl(I) natural plankton assemblages to study occurrence mechanism Tl oxidation. observed Tl(III) comprised 74% total dissolved after 60 h incubation surface waters from Lake Ontario, revealing maximum specific rate 0.014 h-1. No was sterile-filtered control...
The FluoroProbe (FP; bbe Moldaenke, GmbH) is increasingly deployed as a means to measure in situ abundance and composition of phytoplankton communities, yet few rigorous evaluations have been made its performance. In this study, strains were grown under standardized conditions test FP performance across range biomass concentrations (0.2 20 μg chlorophyll (chl a)·L −1 ). estimates vivo chl compared with values from acetone extraction analysis. Overall, detected by the was well correlated...
An electrochemically generated alginate matrix cross-linked with Fe3+ cations was used to entrap lysozyme and then release it upon application of an electrochemical signal. The switchable behavior the hydrogel based on different interaction Fe2+ alginate. oxidized strongly interact resulting in its cross-linking formation hydrogel, while reduced weakly do not keep state. Thus, oxidation iron at +0.8 V (Ag/AgCl) presence resulted Fe3+-cross-linked thin-film electrode surface physically...
We tested the hypothesis that phytoplankton productivity in pelagic Lake Erie is limited by low Fe bioavailability during period of thermal stratification. Iron enrichment (20 and 200 nM Fe) water sampled from eastern basin surface (5 m depth) July 1996 revealed a dramatic 180 30% increase standing crop picoplankton (0.2-2 µm) nanoplankton (2-20 size fractions, respectively. Light-saturated rates photosynthesis for increased 2.8 times controls within 24 h. In contrast, simultaneous P...
ABSTRACT Three strains of Scenedesmus acutus f. alternans Hortobagyi with markedly different sensitivities to copper were examined determine the relative importance cellular polyphosphate content on acute toxicity photosynthesis. By manipulating phosphate concentration in semicontinuous cultures, response each strain was assessed at three phosphorus states: P‐loaded, P‐sufficient, and P‐deficient. The results demonstrated reducing toxic effect photosynthesis; greater P content, less...
Invasive watermilfoils, a group of related aquatic invasive plant species, have been pervasive issue for freshwater lakes throughout temperate regions North America. Management or removal watermilfoils has extensively studied with only limited long-term success reported. Here, we describe an approach to monitor the growth and spread species in shallow dystrophic impoundment at early stages invasion, as understanding halting invasions stage is crucial yet often not successful. Unlike other...
The bioavailability and toxicity of a dissolved metal are closely linked to the metal's chemical speciation in solution. A variety inorganic organic ligands often used laboratory tests control concentration labile trace Computerised models based on thermodynamic principles can be estimate under such experimental conditions. However, these sensitive quality their databases. Detailed protocols for incorporation reliable equilibrium formation constants into widely available computer programs...
Abstract Competitive interaction between Tl(I) and K was successfully predicted by the biotic ligand model (BLM) for microalga Chlorella sp. (Chlorophyta; University of Toronto Culture Collection strain 522) during 96‐h toxicity tests. Because a greater affinity (log = 7.3–7.4) as compared to 5.3–6.3) biologically sensitive sites, an excess 40‐to 160‐fold is required suppress toxic effects on sp., regardless [Tl(I)] in solution. Similar Synechococcus leopoliensis (Cyanobacteria; Texas 625)...