A5003698819- Aquatic Ecosystems and Phytoplankton Dynamics
- Environmental Toxicology and Ecotoxicology
- Heavy metals in environment
- Aquatic Invertebrate Ecology and Behavior
- Fish Ecology and Management Studies
- Water Quality and Pollution Assessment
- Marine and coastal ecosystems
- Geology and Paleoclimatology Research
- Marine Biology and Ecology Research
- Freshwater macroinvertebrate diversity and ecology
- Mercury impact and mitigation studies
- Soil and Water Nutrient Dynamics
- Peatlands and Wetlands Ecology
- Diverse Academic Research Areas
- Water Quality and Resources Studies
- Mine drainage and remediation techniques
- Groundwater and Isotope Geochemistry
- Toxic Organic Pollutants Impact
- Climate change and permafrost
- Oceanographic and Atmospheric Processes
- Fluoride Effects and Removal
- Invertebrate Taxonomy and Ecology
- Diatoms and Algae Research
- Arctic and Antarctic ice dynamics
- Archaeology and Historical Studies
Laurentian University
2013-2024
York University
2016
Ministry of the Environment, Conservation and Parks
2003-2009
Ministry of Environment
1995-2004
While there is a general sense that lakes can act as sentinels of climate change, their efficacy has not been thoroughly analyzed. We identified the key response variables within lake indicators effects change on both and catchment. These reflect wide range physical, chemical, biological responses to climate. However, different affected by regional characteristics catchment, mixing regimes. Thus, particular or combinations are more effective for types geographic regions. The extraction...
Abstract Lake surfaces are warming worldwide, raising concerns about lake organism responses to thermal habitat changes. Species may cope with temperature increases by shifting their seasonality or depth track suitable habitats, but these be constrained ecological interactions, life histories limiting resources. Here we use 32 million measurements from 139 lakes quantify change (percentage of non-overlap) and assess how this is exacerbated potential constraints. Long-term resulted in an...
Ecology Letters (2010) 13: 162–174 Abstract Predicting community and species responses to disturbance is complicated by incomplete knowledge about traits. A phylogenetic framework should partially solve this problem, as trait similarity generally correlated with relatedness, closely related have similar sensitivities disturbance. Disturbance thus result in assemblages of species. We tested hypothesis 18 disturbed 16 reference whole‐lake, long‐term zooplankton data sets. Regardless type,...
Environmental variability in space and time is a primary mechanism allowing species that share resources to coexist. Fluctuating conditions are double edged sword for diversity, either promoting coexistence through temporal niche partitioning or excluding by stochastic extinctions. The net effect of environmental variation on diversity largely unknown. We examined the association between zooplankton richness lakes interannual, seasonal shorter scales, as well long-term average conditions....
Globally, lake surface water temperatures have warmed rapidly relative to air temperatures, but changes in deepwater and vertical thermal structure are still largely unknown. We compiled the most comprehensive data set date of long-term (1970-2009) summertime temperature profiles lakes across world examine trends drivers whole-lake structure. found significant increases at an average rate + 0.37 °C decade-1, comparable reported previously for other lakes, similarly consistent increasing...
En comparant les changements survenus a long terme dans communautes de crustaces zooplanctoniques trois lacs experimentalement chaules situes pres des usines metallurgiques Sudbury (Ontario) avec valeurs temporelles et spatiales mesurees reference distance Sudbury, nous (i) demontrons l'utilite l'etude la restauration d'un bassin lacustre, (ii) comparons indicateurs univaries multivaires (iii) determinons si rapidite depend gravite pollution acide metallique. Les ont permis d'etablir...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTLake acidification: effects on crustacean zooplankton populationsKarl E. Havens, Norman D. Yan, and Wendel KellerCite this: Environ. Sci. Technol. 1993, 27, 8, 1621–1624Publication Date (Print):August 1, 1993Publication History Published online1 May 2002Published inissue 1 August 1993https://pubs.acs.org/doi/10.1021/es00045a019https://doi.org/10.1021/es00045a019research-articleACS PublicationsRequest reuse permissionsArticle...
Abstract In the mid‐twentieth century, many lakes near Sudbury, Canada, were severely contaminated by acid and metal emissions from local smelters. For example, in early 1970s, Middle Lake had pH of 4.2, Cu Ni levels both >0.5 mg L −1 . To determine if crustacean zooplankton could recover such severe chronic damage, was neutralized 1973. A comparison its with that 22 reference (pH > 6) indicates planktonic Copepoda completely recovered 2001. contrast, cladoceran assemblage improved but...
Abstract Mercury (Hg) is an anthropogenic pollutant that toxic to wildlife and humans, but the response of remote ecosystems globally distributed Hg elusive. Here, we use DNA extracted from a dated sediment core infer microbes historical delivery. We observe significant association between mercuric reductase gene (merA) phylogeny timing deposition. Using relaxed molecular clock models, show increase in scaled effective population size merA beginning ~200 years ago, coinciding with Industrial...
The Sudbury region of northeastern Ontario, Canada, provides one the world’s best examples resilience aquatic ecosystems after reductions in atmospheric contaminant deposition. Thousands lakes around metal smelters were badly damaged by acid Lakes closest to also contaminated particulates. However, large SO 2 and emissions starting early 1970s have led widespread chemical improvements these lakes, recovery has been observed for various biota. Studies Sudbury-area are advancing our...
Thousands of lakes in northeastern Ontario, Canada, have been acidified by sulphur deposition associated with emissions from the Sudbury area metal smelters. However, water quality improvements including increased pH and reduced sulphate concentrations followed large reductions that were implemented, beginning 1970s. Substantial decreases Ca accompanied these other changes lakewater chemistry. Monitoring 38 20128 km showed declines concentrations, averaging 2.7 µeq·L 1 ·year , over period...
Large reductions in sulphur emissions at the Sudbury, Ont., Canada, smelters recent decades have resulted decreased lake acidity, and biological improvements followed. Lakes Sudbury area offer a very unique opportunity to develop our understanding of processes regulating restructuring aquatic ecosystems recovering from acidification. Here, we examine changes crustacean zooplankton communities that accompanied chemical recovery Whitepine Sans Chambre lakes, near over last two decades. In both...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTInferred effects of lake acidification on Daphnia galeata mendotaeWendel Keller, Norman D. Yan, Keith E. Holtze, and J. Roger PitbladoCite this: Environ. Sci. Technol. 1990, 24, 8, 1259–1261Publication Date (Print):August 1, 1990Publication History Published online1 May 2002Published inissue 1 August 1990https://pubs.acs.org/doi/10.1021/es00078a015https://doi.org/10.1021/es00078a015research-articleACS PublicationsRequest reuse permissionsArticle...
Summary 1. Recovery of acidified aquatic systems may be affected by both abiotic and biotic processes. However, the relative roles these factors in regulating recovery difficult to determine. Lakes around smelting complexes near Sudbury, Ontario, Canada, formerly acidification metal exploration, provide an excellent opportunity examine communities. 2. Substantial zooplankton communities has occurred lakes following declines acidity concentrations, although toxicity residual metals still...
A modeling approach that was used to predict the toxicity of dissolved single and multiple metals trout is extended stream benthic macroinvertebrates, freshwater zooplankton, Daphnia magna. The predicts accumulation toxicants (H, Al, Cd, Cu, Ni, Pb, Zn) in organisms using 3 equilibrium models define interactions between cations biological receptors (biotic ligands). These differ structure include a 2-site biotic ligand model, bidentate or 2-pKa humic acid model. predicted weighted...
Using a 30-year record of biological and water chemistry data collected from seven lakes near smelters in Sudbury (Ontario, Canada) we examined the link between reductions Cu, Ni, Zn concentrations zooplankton species richness. The toxicity metal mixtures was assessed using an additive Toxic Unit (TU) approach. Four TU models were developed based on total (TM-TU); free ion (FI-TU); acute LC50s calculated Biotic Ligand Model (BLM-TU); chronic (acute adjusted by metal-specific acute-to-chronic...