Research

Freshwater aquatic ecosystems are currently affected by multiple anthropogenic stressors. These stressors include recent climate change, acid rain, contaminant pollution, nutrient enrichment (eutrophication), land-use change (vegetation clearance for agriculture, urbanization etc), reservoir/impoundment construction and exotic species invasions, to name a few.  Environmental monitoring programs of aquatic systems that are based on an ecological perspective (simultaneous monitoring of biological, chemical and physical variables) are relatively new as early programs were designed to monitor the impacts of acidic deposition in the 1970s.  As a consequence, long-term ecological datasets (>20 yrs data) are extremely rare and located primarily in geographic regions downwind of major acidic deposition (north-eastern USA and central Ontario region of Canada).  This lack of long-term ecological data presents difficulties in answering some basic questions that are important to consider when assessing the ecological impacts of stressors: What are ‘natural’ or pre-disturbance conditions of the ecosystem?  What is the natural variability of the system?  It is possible to obtain this long-term data through proxy methods, such as through examination of paleoecological data archived in lake and pond sediments.  Sediments are natural archives of ecological data, with a host of physical, chemical, and biological variables providing insights into past aquatic ecosystem conditions.

Raymond Biastock, PhD Candidate (On leave)

The examination of patterns in the limnological and biological differences of Arctic lakes and ponds as a function of their position in the landscape.

Using a hierarchical classification of Arctic aquatic systems to select study areas, I will sample the physical, chemical, and biological traits of lakes and ponds.  I aim to determine the relative influences of local, watershed-specific factors vs. regional, climate-mediated factors on aquatic ecosystem functioning and structure. With estimates of the relative importance of regional-scale factors on freshwater ecosystems, it would be possible to estimate the relative effects of predicted future climate warming on Arctic lake, pond and river ecosystems.

Christopher Luszczek, PhD Candidate (On leave)

An assessment of the composition, structure and variation of benthic communities in Canadian Arctic lakes and ponds

I will examine the variables responsible for structuring aquatic macroinvertebrate communities Across mainland Nunavut.  I will determine whether community composition primarily represents habitat-scale variables (such as littoral substrate) or landscape-scale variables (such as climate, surrounding watershed vegetation and geology). As such, these research findings have important implications for rapid ecosystem assessment and creating biomonitoring programs. This research will hopefully provide valuable information for better understanding ecosystem functioning in these sparsely studied Arctic systems

Ryan Scott, PhD 2021

The ecology and biogeography of benthic macroinvertebrates in the Mackenzie River Delta, Northwest Territories

My thesis aimed to examine invertebrate community ecology and food web structure in small lakes and ponds in the Mackenzie River Delta in the Northwest Territories, focusing on the response of aquatic communities to gradients in floodplain connectivity. My research will shed light on ecosystem structure and function in Arctic floodplain environments, and be of value in monitoring and predicting climate-driven changes in sensitive northern aquatic ecosystems.

Dmitri Perlov, MSc 2017

Inferring past deepwater oxygen in the central basin of Lake Erie using a paleolimnological approach

My thesis used a paleolimnological approach, using subfossil Chironomidae remains preserved in Lake Erie sediments, to reconstruct past hypolimnetic oxygen conditions.  Climate change and nutrient loading have had substantive effects on Lake Erie’s productivity and deepwater(hypolimnetic) oxygen concentrations. To date, numerous limnological papers have been published on the subject of hypolimnetic oxygen dynamics in the central basin of Lake Erie. However, such studies provide information on hypolimnetic oxygen during a period of monitoring that comprises approximately five decades of data, while a paleolimnological approach may generate centuries of data, providing background or baseline environmental data which can be used to better understand Lake Erie’s ecosystem dynamics. 

Andrew Medeiros, PhD 2011

A biogeographic examination of climate driven impacts to Arctic aquatic systems

http://www.inuk.ca

Kristin Wazbinski, MSc 2011

Paleolimnological analysis of nutrient enrichment for criteria development in New Jersey and New York lakes

Kristin examined surficial intervals of sediment cores from shallow, polymictic lakes in the New Jersey and New York states in USA, to determine which limnological variables were influencing ecological gradients in subfossil Dipteran (Ceratopogonidae, Chironomidae, Chaoboridae, Simuliidae) and Ephemeropteran assemblages.

Armin Namayandeh, MSc 2009

Diversity and distribution of benthic invertebrates in lakes and ponds of Nunavut, Canada

Armin examined patterns in benthic macroinvertebrates in a suite of lakes and ponds in the vicinity of Rankin Inlet and Iqaluit, Nunavut.  Shoreline samples of benthic invertebrates were collected using 500-µm mesh D-nets, and community composition of these samples was analyzed using multivariate statistics (e.g. Redundancy Analysis, RDA) to determine which environmental gradients are primarily responsible for structuring macroinvertebrate communities in these water bodies.

Danielle Rodé, MSc 2009

A paleolimnological approach to assessing the sustainability of the Lake Simcoe cold-water fishery based on historic habitat quality and fish abundances

Danielle used a paleolimnological approach to determine how hypolimnetic dissolved oxygen concentrations and fish abundances have changed in Lake Simcoe since European settlement.  Historic hypolimnetic oxygen levels were quantified using a chironomid-based inference model. Fish abundances were reconstructed using subfossil Daphnia ephippia as indicators of past planktivorous predation pressure (as a proxy for fish abundance).  The purpose of this research is to determine if current rehabilitation goals to remediate Lake Simcoe water quality represent natural historic conditions of the lake system.

Fatemeh Panahi Dorcheh, MSc 2007

Inferring past fish abundance from Daphnia ephippia size in south-central Ontario lakes

Fatemeh processed surficial intervals of sediment cores from 50 lakes located in the Sudbury and Muskoka-Haliburton regions of south-central Ontario.  An inference model was developed using the dorsal length of subfossil Daphnia ephippia as a proxy indicator of fish abundance (expressed as planktivorous fish CPUE).