A5030814697- Aquatic Ecosystems and Phytoplankton Dynamics
- Geology and Paleoclimatology Research
- Isotope Analysis in Ecology
- Climate change and permafrost
- Fish Ecology and Management Studies
- Peatlands and Wetlands Ecology
- Soil and Water Nutrient Dynamics
- Freshwater macroinvertebrate diversity and ecology
- Aquatic Invertebrate Ecology and Behavior
- Pesticide and Herbicide Environmental Studies
- Coastal wetland ecosystem dynamics
- Marine and coastal ecosystems
- Pharmaceutical and Antibiotic Environmental Impacts
- Ecology and Vegetation Dynamics Studies
- Plant and animal studies
- Flood Risk Assessment and Management
- Hydrology and Watershed Management Studies
- Environmental Toxicology and Ecotoxicology
- Species Distribution and Climate Change
- Insect and Pesticide Research
- Cryospheric studies and observations
- Insect and Arachnid Ecology and Behavior
- Soil Carbon and Nitrogen Dynamics
- Microplastics and Plastic Pollution
- Karst Systems and Hydrogeology
Pennsylvania State University
2022-2024
North Dakota State University
2017-2022
Dakota State University
2022
Parks Canada
2010-2015
University of Waterloo
2011-2015
Alberta Innovates
2014
Queen's University
2003-2011
University of Regina
2007
University of Alaska Fairbanks
2000-2003
Abstract Ponds are often identified by their small size and shallow depths, but the lack of a universal evidence-based definition hampers science weakens legal protection. Here, we compile existing pond definitions, compare ecosystem metrics (e.g., metabolism, nutrient concentrations, gas fluxes) among ponds, wetlands, lakes, propose an definition. Compiled definitions mentioned surface area depth, were largely qualitative variable. Government legislation rarely defined despite commonly...
The effects of climate variability on Pacific salmon abundance are uncertain because historical records short and complicated by commercial harvesting habitat alteration. We use lake sediment δ 15 N biological indicators to reconstruct sockeye in the Bristol Bay Kodiak Island regions Alaska over past 300 years. Marked shifts populations occurred decades during this period, some pronounced changes appear be related climatic change. Variations returns due or can have strong impacts nursery...
Abstract Lakes are classified by thermal mixing regimes, with shallow waterbodies historically categorized as continuously systems. Yet, recent studies demonstrate extended summertime stratification in ponds, underscoring the need to reassess classifications for waterbodies. In this study, we examined dynamics of 34 ponds and lakes across temperate North America Europe categorize identify drivers different regimes. We identified three regimes: rarely ( n = 18), intermittently 10), often 6)...
Wetlands play a disproportionate role in the global climate as major sources and sinks of greenhouse gases. Herbicides are most heavily used agrochemicals frequently detected aquatic ecosystems, with glyphosate 2,4-Dichlorophenoxyacetic acid (2,4-D), representing two commonly worldwide. In recent years, these herbicides being mixtures to combat herbicide-tolerant noxious weeds. While it is well documented that herbicide use for agriculture expected increase, their indirect effects on wetland...
We examine the role of local environmental and spatial factors in explaining variation composition cladoceran assemblages from surface sediments within a set 50 lakes spanning broad southwest to northeast transect across central Canadian Arctic treeline region Yellowknife (Northwest Territories) northern boundary Thelon Game Sanctuary (Nunavut Territory). Within each lake, fauna was identified based on subfossil exoskeletal remains preserved recently deposited lake sediments. Physical...
Zooplankton communities in Boreal Shield lakes of south-central Ontario, Canada, have become increasingly exposed to the effects multiple anthropogenic stressors, such as declines calcium (Ca) and total phosphorus (TP) concentrations, shifts predation regimes, climate warming. The paleolimnological approach provides an effective means examining cladoceran zooplankton prior onset these major environmental stressors assessing how increasing impacts affected community composition. We examined...
Abstract. The structure, function, and dynamics of Earth's terrestrial ecosystems are profoundly influenced by how often (frequency) long (duration) they inundated with water. A diverse array natural human-engineered systems experience temporally variable inundation whereby fluctuate between non-inundated states. Variable spans extreme events to predictable sub-daily cycles. Variably (VIEs) include hillslopes, non-perennial streams, wetlands, floodplains, temporary ponds, tidal systems,...
Abstract Recent studies using remote sensing analysis of lake‐rich thermokarst landscapes have documented evidence declining lake surface area in response to recent warming. However, images alone cannot identify whether these declines are due increasing frequency drainage events associated with accelerated activity or evaporation longer ice‐free season duration. Here, we explore the potential combining aerial photograph time series paleolimnological analyses track changes hydrological...
Shallow lakes are dominant features in subarctic and Arctic landscapes responsive to multiple stressors, which can lead rapid changes limnological regimes with consequences for aquatic resources. We address this theme the coastal tundra region of Wapusk National Park, western Hudson Bay Lowlands (Canada), where climate has warmed during past century Lesser Snow Goose (LSG; Chen caerulescens caerulescens) population grown rapidly ∽40 years. Integration paleolimnological analyses documents...
Climate variations exert rapid and strong control on the hydrology of shallow lake-rich subarctic landscapes, but knowledge associated effects limnological conditions remains limited. Based analysis water isotope compositions chemistry at 56 lakes across Old Crow Flats (Yukon), a large thermokarst landscape, we assess if differences in source inputs (snowmelt versus rainfall) affect during ice-free season 2007 explore influences catchment features. Results demonstrate that with...
Arctic and subarctic ecosystems have undergone considerable environmental changes in recent years as the result of climate warming. Fossil records freshwater diatoms lakes throughout circumpolar Arctic, including central Canadian treeline region, revealed marked directional shifts diatom assemblages lake sediments. These algal been linked to longer growing seasons, decreased duration ice cover, and/or increased thermal stability. The effects these on higher trophic levels, such Cladocera,...
Northern regions are expected to experience large environmental change over the next few decades. The response of biota will depend on changes in local environment, regional processes that influence lake connectivity, and species interactions. In 2008, we surveyed 92 lakes ponds across Wapusk National Park, located southwestern shore Hudson Bay. At each site assessed water chemistry zooplankton community composition. an effort understand how aquatic ecosystems respond future change,...
Interactions between climate and hydrogeologic settings contribute to the hydrologic chemical variability among depressional wetlands, which influences their aquatic communities. These interactions resulting have led inconsistent results in terms of identifying reliable predictors aquatic-macroinvertebrate community composition for wetlands. This is especially true Prairie Pothole Region North America where, addition pronounced variability, studies are often confounded by fish introductions....
Metal contamination of freshwater ecosystems is increasingly prevalent due to anthropogenic activities such as metal smelting and fossil fuel combustion. While toxicological studies focus on aqueous concentrations that result in lethal or sublethal responses, currently the only method for reconstructing a lake's history through an examination sedimentary deposits. In this paper, we suggest cladoceran diapausing eggs (ephippia), which are abundant nature accumulate maternally derived metals,...
The past ∼40 years have seen a geometric increase (5–7% per year) in the size of lesser snow goose (LSG; Chen caerulescens caerulescens) population and marked spatial expansion area they inhabit within coastal fen ecotype Wapusk National Park (Hudson Bay Lowlands, northern Canada), raising concerns uncertainty about environmental effects their activities (grubbing vegetation, soil disturbance, deposition feces) on abundant shallow tundra ponds. In this study, we use conventional limnological...
Abstract Cladocera serve as important bio‐ and paleo‐indicators of lake food webs environmental conditions. The ecological optima cladocerans are often established by regional‐scale calibration sets, with subsequent comparisons to limnological variables. However, due logistical constraints when sampling large numbers lakes, this approach limits the length gradients that can be examined. To extend spatial gradients, we combined 20 datasets (388 lakes) containing both cladoceran data, spanning...