Healthy land is clearly a prerequisite for healthy water in any catchment area, however the specific value of terrestrial organic matter (e.g. leaf litter, dissolved carbon (DOC)) has only recently been appreciated. For example, in some small lakes as much as 70% of the productivity of the aquatic systems is derived in the terrestrial environments. Our research project in land /water interactions is focused on understanding the role of terrestrial carbon and base cations in the recovery of severely damaged ecosystems from stressors such as mining, smelting, fire and logging. This NSERC industrial project is called TALER (Terrestrial Aquatic Linkages for Ecosystem Recovery) and involves faculty and students at Laurentian ( J. Gunn, B. Keller, N. Mykytczuk), York ( N. Yan, M. Celis-Salgado, A. Tanentzap), Trent (S. Watmough), Wilfrid Laurier (J. McGeer), Queens (S. Arnott) and the Can. For Service lab in Sault Ste. Marie( D. Kreutzweiser). The industrial partners are Vale Ltd and Xstrata Ltd, with additional support from the City of Greater Sudbury. Background information for the project can be found in Szkokan–Emilson et al. 2011 ( PDF).
The TALER project makes use of study sites and facilities at:
- Long-term study sites in Sudbury, Ont.
- CFS experimental watershed sites in White River, Ont.
- FLAMES toxicity lab in Dorset, Ont.
- FAME microbial ecology lab at Laurentian
Supervisor: Dr. Jim McGeer, Wilfrid Laurier University
I am an MSc student studying the influence of dissolved organic matter (DOM) source quality on acute and chronic copper toxicity to Hyalella azteca. DOM plays an important role in the recovery of damaged aquatic ecosystems, particularly those impacted by metals. The aim of this research project is to examine the DOM has been collected (via reverse osmosis concentration) from sites that have been disturbed by logging, fire and long term smelter emissions or from reference sites. An understanding of the quality of different types of DOMs is related to the severity of ecosystem disturbance and Cu toxicity mitigation is a main focus of this study. Overall this work is directed towards better comprehending aquatic-terrestrial linkages. It has been found that disturbed sites offer less protection against Cu toxicity compared to undisturbed reference sites. Both the type and severity of ecosystem disturbance have an influence on the protective capacity of DOM. Tests to compare the quality (based on toxicity mitigation) of DOM sources demonstrate clear differences that can be related to the capacity to complex Cu (ion selective electrode) and optical characteristics (absorbance and excitation emission matrix spectroscopy (EEMS)). The absorbance of DOM sources at 340 nm provides a clear correlation with protectivity and may act as a rapid method for predicting DOM quality. EEMS, in conjunction with PARAFAC analysis, has been found to be useful in terms of modeling by taking into account the relative composition characteristics of each DOM source. An improved understanding of DOM quality can be useful in improving predictions of Cu toxicity in freshwater systems. Chronic studies are currently underway to see if the DOM source variations are as distinct over long-term exposure.
Supervisor: Dr. Shaun Watmough, Trent University
Thesis Title: Microbial biomass and aerobic respiration along a historic pollution gradient in Sudbury, Canada wetlands
Synopsis:I have recently completed my Honours BSc at Trent University where I pursued my keen interest in the natural environment through a joint major in Environmental / Resource Science and Biology. During my undergraduate degree I had the fantastic opportunity to complete an honours thesis with Dr. Shaun Watmough as a component of the TALER (Terrestrial Aquatic Linkages for Ecosystem Recovery) project. My research focused on examining microbial biomass and aerobic respiration to determine whether pollution-“impacted” fens in the Sudbury area have impaired microbial communities. I am currently enrolled in the post-graduate Geographic Information Systems (GIS) program at Sault College while working part time as a Fisheries Resource Technician for Harkness Laboratory of Fisheries Research (Ontario Ministry of Natural Resources). In the future I hope to integrate my GIS skills with my research interests in fish communities and the hydrological consequences of disturbance.
The recovery of historically degraded landscapes in Sudbury, Ontario has been studied to a lesser extent with respect to both wetlands and microbial communities. Wetlands are important for biogeochemical transformations and export of organic matter to downstream systems; within wetlands the microbial communities play a crucial role in decomposition. The objective of this study is to assess whether “impacted” wetlands in the Sudbury region have impaired microbial communities. Eight fens were selected along a distance gradient from the smelters from which peat and pore water were analyzed for various chemical and physical parameters. Basal microbial respiration, relative response to substrate addition and microbial biomass carbon were also assessed using substrate induced respiration and a fumigation incubation method. Fens closer to the Copper Cliff smelter have higher concentrations of Cu and Ni as well as more humified peat and DOM. Microbial functional ability does differ between wetlands. Basal respiration rates are, however, related to the humification of the peat, which is potentially related to environmental degradation in the fens or surrounding terrestrial systems.
Supervisors: Dr. Gunn (Laurentian University) and Dr. Watmough (Trent University)
Thesis Title: Biogeochemical Processing and Flux of Nutrients and Metals from Lowland Wetlands: Importance to Recolonizing Aquatic Communities in Lakes.
Synopsis: I am a Ph.D. student under co-supervision by Dr. Gunn (Laurentian University) and Dr. Watmough (Trent University). I am interested in the influence of biogeochemical processes in watersheds on lakes. My research investigates the cycles and fluxes of nutrients and metals from lowland wetlands to lakes, across a disturbance gradient (mining, forestry, fire) and during extreme events such as drought. These disturbances have the potential to alter natural biogeochemical cycles, resulting in changes to water quality that could have dramatic effects on the biology of lake ecosystems. I am also interested in the trophic subsidy of aquatic communities by terrestrial-derived carbon, and the influence of disturbance on this important relationship. I believe that ecological research should be directly applicable, and so I keep my work closely in line with efforts to recover disturbed ecosystems.
Supervisors: Dr. Nadia Mykytczuk and Dr. John Gunn (Laurentian University)
Synopsis: Microbial communities support aquatic ecosystems through their cycling and production of key elements and nutrients required by living organisms. Natural and industrial disturbances such as fire, logging, acid deposition and metal contamination have an impact on aquatic ecosystems. As microbial communities play such a critical role in the functioning of natural aquatic ecosystems, understanding how microbial communities are responding to these disturbances will provide insight into the recovery process. My study is investigating the role of microbial community abundance, structure and activity in the processes promoting aquatic ecosystem recovery following natural and industrial watershed disturbance. The approach is to assess the ecological integrity and state of recovery across a gradient of disturbance (old/recent logging, fire, industrial acidification and metal deposition) by linking catchment characteristics with stream habitat characteristics and biotic measures such as leaf litter decomposition, enzyme activity and microbial community structure. Early results show that microbial decomposition rates are similar among reference sites and sites that have experienced disturbance from fire and logging, while microbial decomposition rates in sites that have experienced industrial disturbance are significantly lower.
Supervisor: Dr. Shaun Watmough (Trent University)
Thesis Title: Spatial and temporal variations in peatland geochemistry in Sudbury Ontario
Synopsis: The damage to the Sudbury landscape from over a century of smelter activity has been severe and impacts on aquatic and terrestrial ecosystems are well-documented (Gunn, J., 1995, Szkokan-Emilson et al. 2011). However, despite their abundance in the region, wetlands have received much less attention. The Sudbury Soil Risk Assessment (2001-2008) identified that nutrient limitations is as much a problem as metal toxicity and highlighted not only the importance of wetlands but the need for more detailed studies examining the role of wetlands in the recovery of lakes. The objective of this work is to evaluate the spatial and temporal variability in the geochemistry of 18 wetlands (poor fens) extending along a historic pollution gradient in Sudbury Ontario (5 km to 45 km from Copper Cliff smelter). Peat and pore-water chemistry in Sudbury peatlands exhibits tremendous spatial and temporal variability. The historic pollution gradient is still evident in Cu and Ni concentrations in peat, but pore-water chemistry also appears strongly influenced by natural factors such as groundwater and peat carbon content. In addition, redox processes are significantly contributing to temporal variations in pore-water chemistry. Despite the large spatial and temporal variability in pore-water chemistry. Soil-solution partitioning of some metals can be explained by pH alone. Ongoing (multi-variate) analysis will further seek to characterize the geochemistry of Sudbury peat-lands. This research will contribute significantly to historic data concerning a region severely impacted by over a century of industrial emissions. Gaining a thorough understanding of wetland geochemistry can provide valuable insights into a wetlands contribution and influence over ecosystem health and aid in determining why Sudbury lakes are not responding, as they should from such drastic reductions in emissions over the last 2 decades.
Supervisor: Dr. Shaun Watmough (Trent University)
Thesis Title: Impacts of simulated drought on pore water chemistry of peatlands in the Greater Sudbury Area, Ontario
Synopsis: Extreme weather events, including prolonged droughts, are anticipated to increase due to climate change. One adverse effect of droughts is the temporary acidification of peatlands. During a severe drought event, peatlands experience a water table draw down, which exposes reduced sulphur to oxygen, converting it to sulphate (SO4). Upon rewetting, SO4 is converted to sulphuric acid (H2SO4), which reduces pH and increases metal concentration. This risk is of particular concern for peatlands in the Greater Sudbury Area because of the regions mining and smelting history. The objectives of the present study are to determine the impacts of a 30 and 60 day drought (severity) on the pore water chemistry of peatlands sampled along a distance gradient in the Greater Sudbury Area and to assess the possibility of liming as a remedial strategy. Peat samples were collected from the surface of six peatlands with different baseline chemistries during early summer. A 30 day drought, plus control, and a 60 day drought, plus control, were simulated under laboratory conditions. Pore water pH was lower in drought treatments compared with the control in each of the peatlands and the decline was considerably more pronounced following the 60 day drought treatment. Nitric acid was a much greater contribution to peatland acidity after a 60 day drought compared with a 30 day drought. Concentrations of several metals, such as Ni, were much higher in pore waters of the drought treatments compared with the control and increases were substantially greater following the 60 day drought. This study shows that drought severity influences the severity of the acid-pulse and metal release in Sudbury peatlands.
Supervisor: Dr. Shaun Watmough (Trent University)
Thesis Title: Impact of Industrial Pollution on the Community and Biochemistry of Wetland Vegetation
Synopsis: The mining and smelting industries that once dominated Sudbury, Ontario have left a significant ecological footprint on the landscape, and wetlands in the region are both acidic and contaminated with metals. There is much concern regarding the delayed biological recovery of the watersheds and little is known about the wetland vegetation and their role in the recovery of these systems, or indeed if they are impacted by current conditions in the wetlands. The objective of this research is to assess the relationships between wetland vegetative communities and key biochemical markers (e.g. total phenols and anthocyanins) and peatland (peat and porewater) chemistry. Eighteen wetlands along a historical pollution gradient were selected and vascular plant communities were assessed (richness, Simpsons Index etc.) using sixteen 1m2 quadrats per wetland and the metal and nutrient content in peat and common plant species (eg. Kalmia angustifolia, Chamaedaphne calyculata) will be measured using standard techniques. The biochemical markers, including the secondary metabolites which studies have shown to be indicators for industrial pollution, as well as chlorophyll, will also be analyzed. Future sampling with a more in depth characterization of the phenolic contents of the plants and peat, as well as a nonvascular community assessment will continue the summer of 2013.
Supervisor: Dr.Jim McGeer (Wilfred Laurier) and Dr. Norman Yan (York University)
Thesis Title: Factors affecting Ni Toxicity in Hyalella azteca
Synopsis: The focus of these studies is to determine the influence of Ca2+, Mg2+ and natural organic matter (NOM) on the acute and chronic toxicity of Ni to Hyalella azteca. Amphipod cultures (source: Hannah Lake) were established over 6 months and acclimated to very low Ca levels (0.1 mM Ca, 0.025 mM Mg, 0.1 mM Na, 0.1 mM Cl, pH 7, temp 20oC) prior to testing. Culturing and testing protocols followed Environment Canada standard methods (1997 EPS RM/33). In acute exposures, increasing Ca (0.1 – 2.0 mM) significantly reduced Ni toxicity by 6-fold (LC50 values increased from 0.56 mg/L to 3.2 mg/L). Increased waterborne Mg to 0.5mM did not provide protective effects on acute Ni toxicity and may have acted as a stressor as survival of controls with increased Mg was reduced. The protective effects of NOM were assessed on the basis of dissolved organic carbon (DOC) quantity as well as quality. NOM at concentrations of 6 mg C/L and above showed significant protective effects against Ni toxicity, similar to the acute Ca series. NOM was collected from various sites near White River (3 sites), Sudbury (4 sites; a wetland above Laurentian Lake and then Daisy, Laurentian and Clearwater lakes) and also in the Muskoka region (5 sites; a stream flowing into Harp Lake (HP3), Harp Lake, Plastic Lake (PL) and 2 streams associated with Plastic Lake (PC01 – outflow from a wetland above PL and P108 – inflow into a wetland above PL)). Exposures with NOM at 6 mg C/L showed that some sources offered more protection than others. Short term Ni accumulation (whole body dry weight basis) was used to examine linkages between toxicity and bioavailability/uptake and showed that the tissue burdens associated with toxicity varied tremendously (range of 20 and 500 μg Ni/g dwt). Unexpectedly, the protective effects of NOM on acute Ni toxicity were not correlated to optical characteristics (e.g. SAC340, FI and the humic acid %, fulvic acid % as determined by excitation emission matrix spectroscopy). In chronic exposures the addition of toxicity modifying factors resulted in improved growth compared to Ni only exposures. An increased Ca concentration of 1mM reduced Ni toxicity by a factor of 2 however survival was low in the controls with elevated Ca (no added Ni). It is possible that increased amounts of Ca trigger a stress response that counteracts its protective effect. The controls with 6 mg DOC/L did not show this impaired survival effect. Daisy Lake NOM protected against chronic Ni toxicity about 3-times better than Plastic Lake. This protective effect was unexpected because the results of acute testing showed that Daisy Lake NOM was less protective compared to Plastic lake NOM. These results are considered in the context of the biotic ligand model and understanding the importance of NOM source.
Supervisor: Dr. Shelly Arnott (Queen’s University) and Dr. John Gunn (Laurentian University)
Thesis Title: Landscape-level effects on a freshwater amphipod at the land-water interface
Synopsis: Determining how acid- and metal- sensitive populations including the freshwater amphipod, Hyalella azteca, respond to subcatchment characteristics across spatial and temporal gradients of recovery can provide useful insight in guiding restoration practices. From periodic surveys, this amphipod has re-established populations across the landscape over the past 20 years. Here we present preliminary results from a six lake study assessing how subcatchment characteristics (e.g.topography and vegetation) might influence distribution and abundance of H. azteca across spatial (e.g. degree of historical watershed disturbance) and temporal (e.g. colonized for H. azteca abundance accounting for variation at the lake-level. Averaging across preliminary candidate models, H. azteca abundance is positively influenced by higher proportions of macrophyte cover and a positive interaction between subcatchment size and the proportion of moderate topographic index values (moderate slope, moderate potential for water accumulation). This indicates that as subcatchment area increases, the positive effect of moderate slopes and water accumulation on H. azteca abundance increases. These GIS tools can also be used in other studies to predict the influence of landscape on water or recovery across the region.