Lake Melville: Avativut, Kanuittailinnivut
Since 1970, the Churchill River in central Labrador has been diverted from its natural channel through a hydroelectric power generating station at Churchill Falls and the headwaters have been controlled through the creation of the Smallwood Reservoir. The downstream effects of this Upper Churchill project on Lake Melville, the large saltwater estuary that drains the Churchill River into the Labrador Sea, are largely unknown, although recent fish studies have documented elevated mercury levels and local residents have observed changes in wildlife, sea ice, water quality, and climate, among others, since the 1970s. A second hydroelectric scheme, the Lower Churchill project, is now proposed for the Churchill River at Muskrat Falls, about 25 km upstream of Lake Melville. Flooding of its associated 59-km-long reservoir is scheduled to begin in 2016.
The Lake Melville program is a research monitoring program developed by the Nunatsiavut Government (Environment Division), co-led by Trevor Bell at Memorial University. The program will establish baseline conditions for Inuit health, community wellbeing and ecosystem integrity prior to industrial hydroelectric upstream of Inuit territory. Through this program, we are reflecting on the monitoring and indicators of change that have been used, identifying long-term trends and gaps in our understanding, and learning how to improve the science of monitoring for future developments. The knowledge gained will inform environmental management, planning and decision-making.
Two main goals of Lake Melville: Avativut, Kanuittailinnivut are:
Effects of development such as the Upper Churchill project and Lower Churchill project are significant stressors on community wellbeing. Commonly, the resulting change is seen in loss of traditional lifestyles, cultural strength, and social stability. Inuit and other Arctic communities face large-scale challenges due to climate change, resource development and other forces, and it is essential that planning for the future includes not only economic goals but also social and cultural ideals and objectives.
Key ecosystem indicators sensitive to the proposed changes in oceanography, sea ice regime and benthic habitats will be identified, tracked to establish baseline conditions, and integrated into an ecosystem monitoring plan. In partnership with the Government of Nunavut (Fisheries and Sealing) and the Ocean Mapping Group at the University of New Brunswick, we were able to use Nunavut-owned fisheries research vessel, the MV Nuliajuk, to conduct seabed mapping in Upper lake Melville to create an accurate bathymetry and bottom-type classification and to support the mercury and oceanographic modeling (Figures 1).
Benthic refers to anything associated with or occurring on the bottom of a body of water. The animals and plants that live on or in the bottom are known as the benthos. Lake Melville’s benthic habitat supports a diversity of marine life and is important for the health of the environment. Knowledge on benthic habitats in the area is relatively limited. The main objectives of this study are to collect baseline information to develop a better understanding of the benthic habitat. This includes seafloor mapping, which is an efficient way of gathering baseline information about the nature and distribution of benthic habitats. Knowing the shape of the seafloor is critical to advancing our knowledge of Lake Melville, to map the seafloor involves using multibeam bathymetry, which gives us an image of the topography of the bottom of the lake as well as backscatter data providing insight into the geologic makeup of the seafloor. After two seabed mapping surveys in 2012 much of Goose Bay and the outlets of the major rivers (Kenamu, Northwest, Goose, and Churchill Rivers) which empty into Lake Melville were mapped (Figure 2).
The Lake Melville program began ocean observations in 2012 in July with the release of two seabed moorings for oceanographic monitoring. The oceanographic dynamics of Lake Melville are strongly controlled by the long and very active sill/shoal that is near Rigolet. The presence of the sill near Rigolet creates unique oceanographic conditions in the inlet because it restricts the water exchange between the lake and open sea, and permits part of the tidal energy to enter the lake. Seabed moorings are used to study water properties and flows in and out of the lake, they were released on either side of The Narrows near Rigolet (Figure 3). These moorings allowed us to make direct observations of water properties and currents in Lake Melville in 2012. Figure 4 are two graphs showing the recorded surface outflow was very intense (greater than 40 cm/s inside the lake and 50 cm/s outside the sill). These preliminary results show Lake Melville is a very dynamic region, with currents of greater than 3-4 m/s in the Narrows, with strong oceanographic forcing and very intense freshwater inflows from numerous rivers. These various features pose a challenge to understand how heavy metals might move through this system and how the changing climate and freshwater conditions might influence this heavy metal cycling and the primary productivity of the lake.
While the observations of the lake can tell us a great deal, and will be used quite directly, in order to better understand the dynamics and different influences of Lake Melville an ocean model will be developed of the area. This is being done at Memorial University Department of Physics and Physical Oceanography at Memorial University. Models are an essential tool for understanding and investigating the dynamics of Lake Melville of the general circulation in order to gain a fundamental understanding of the lakes e.g. the seasonal cycles, circulation patterns, and other forms of natural variability. Once we have confidence in the model, we can begin to explore sensitivity by using the model to test the sensitivity of the oceanography to changes in the seasonal cycle of freshwater runoff coming from the rivers. We can also then make comparisons between observed and modeled sea-ice dynamics. What determines the time of freeze-up and how will changes in freshwater runoff influence both freeze-up and breakup? We have also started work on development of an ecosystem model coupled to the physical ocean model, with the goal of this work is to assess the recent climate changes in the region and their impact on the ecosystem. All these models will help us understand and pinpoint any changes that may happen when Muskrat Falls hydroelectric generation project becomes operational.
Mercury is an element that has been known to be a powerful toxin to humans for centuries; one of its most toxic forms is methlymercury. Mercury in the Labrador environment needs to be understood, because it is able to transfer into the food chain and as a result of biomagnification in marine food webs can reach levels of concern for human health. This is a serious problem for people who rely on hunting and fishing for their nutritional, social and cultural wellbeing. Inuit populations who are particularly at risk for high exposure to mercury, due to high consumption rates of fish and marine mammals in their diet. Flooding associated with the creation of new reservoirs for hydroelectric development has been shown to increase bioaccumulation of mercury in fish and seals through a combination of factors that enhance methlymercury production in aquatic environments. We are investigating biogeochemical controls on methlymercury dynamics in the estuary to evaluate the potential impact of development on Inuit health. The first year of field studies led by a team of researchers from Harvard University school of public health collected water, sediment and plankton samples across the lake (Figure 5) on board the Inuit owned vessel MV What’s Happening. Our preliminary observations suggest that rivers are the main source of total mercury to the water column and sediment of Lake Melville and that the influence of major rivers can be detected in Lake Melville at least 150 km from where they enter the inlet. Preliminary results from 2012 data collection have generated a budget for total mercury in (mole/year) Lake Melville (Figure 6). Figures 7 and 8 shows the total mercury and methlymercury distribution in Lake Melville. These results are preliminary and will be added to as more data is collected this year in 2013 and possibly into 2014. It is important to collect quality data now before the Muskrat Falls hydroelectric generation project becomes operational, in order to have a baseline comparison of mercury in the lake prior to any changes in the environment.
Research Partners and Affiliations
- Trevor Bell – Professor Memorial University, Department of Geography
- Tom Sheldon – Director Environment Division, Nunatsiavut Department of Lands and Natural Resources
- Brad de Young – Professor Memorial University, Department of Physics and Physical Oceanography
- Entcho Demirov– Professor Memorial University, Department of Physics and Physical Oceanography
- Joel Finnis– Professor Memorial University, Department of Geography
- Zou Zou Kuzyk – Assistant Professor University of Manitoba, Department of Geological Sciences
- Prentiss Balcom – University of Connecticut, Department of Marine Sciences
- Evan Edinger – Professor Memorial University, Department of Geography
- Chris Furgal – Professor Trent University, Department of Indigenous Environmental Studies
- John Hughes Clark – Professor Ocean Mapping Group University of New Brunswick, Department of Geodesy and Geomatics Engineerin
- Robert Mason – Professor University of Connecticut, Department of Marine Sciences
- Elsie Sunderland – Professor Harvard University, School of Public Health
- Amina Schartup – Post Doctoral Research Fellow Harvard University, School of Public Health
- Zhaoshi Lu – PhD student Memorial University, Department of Physics and Physical Oceanography
- Nonna Belalov – Masters student Memorial University, Department of Physics and Physical Oceanography
- Ryan Calder – PhD student Harvard University, School of Public Health
- Trevor Bell
- John Hughes Clarke
- Brad de Young
- Entcho Demirov
- Evan Edinger
- Joel Finnis
- Chris Furgal
- Zou Zou Kuzyk
- Robert Mason
- Elsie Sunderland
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