Biogeochemistry of Lakes in the Mackenzie Delta
Principal Investigator: Lesack, Lance (23)
Licence Number: 12915
Organization: Simon Fraser University
Licensed Year(s): 2017 2016 2015 2014 2010 2009 2007 2006 2005 2004 2003 2002 2001 2000 1999 1998 1997 1996 1995 1994 1993
Issued: Jun 07, 1997
Project Team: Margaret Squires, Christopher Teichreb

Objective(s): Flooding and annual delivery of nutrient rich sediments are perceived to control the productivity of lakes and wetlands associated with the floodplains and deltas of major world rivers. However, there remains limited understanding of how nutrients cycle through these ecosystems. Least understood are north-flowing ice-covered rivers. If we are to anticipate potential changes to these ecosystems resulting from economic development or from global warming our basic understanding of these systems must be improved. The long-term goal of this research is to develop a model of the interacting biogeochemical and hydrologic processes that control the nutrient balance and primary productivity of lakes in the Mackenzie Delta region, and ultimately, a more general model for lakes associated with the floodplains and deltas of major world rivers. The shorter range goal is to identify & develop models of critical interlinkages between biogeochemical and hydrologic processes that are important to the ecological characteristics of the Mackenzie Delta Lakes.

Project Description: Work based at the Inuvik Research Centre & will consist of field and lab work focused on 6 to 9 small lakes in the Delta near Inuvik. Field work will involve day trips by boat or helicopter to delta lakes. Two specific studies to be done include: 1) Evaluation of the rates of growth among groups of microscopic aquatic plants among a set of lakes that range from non-transparent to relatively transparent. Will improve understanding of how changes in the delta sedimentation regime could affect the amount of plant growth at the base of the aquatic food chain. Will involve collecting samples of algae from lakes every 2 weeks and bringing these to Inuvik for lab-based measures of growth rates under similar conditions. A chain of delta lakes will be identified where obvious changes in transparency are maintained throughout the summer. 2) Evaluation of average amount of light available for plant growth in a set of lakes ranging from non-transparent to transparent. Will provide more precise assessment of how average light transparency over the summer growing season is controlled by the frequency of lake flooding and how this in turn effects the distribution of aquatic plants among the full range of delta lakes. This work involves setting up instrumentation to continuously record light penetration (transparency) over the summer at selected locations in the lakes and collecting water samples for measurement of the concentration of suspended sediments and chemical nutrients associated with changes in water transparency.