The Mackenzie River Delta of the western-Canadian arctic is an extremely lake-rich environment (45,000 lakes) and is the second largest of such delta systems in the circumpolar arctic. The replenishment of water and nutrients in the lakes of this system are dependent on river flooding, which is largely controlled by ice-jamming in the Mackenzie River during spring breakup. Because the arctic may represent the most rapidly warming region of the planet, the degree of river ice-jamming may diminish. However, other stresses are also being imposed on the major northward-draining river systems of the circumpolar region, such as changes in basin land use, flow regulation - water use, and ultra-violet light, and increases in relative sea level. The deltas at the terminal points these river systems represent "hot-spots" of biological productivity in the arctic and important aquatic resources for the people who live there. These systems may change considerably over the next 50-100 years, yet they have remained a greatly understudied class of aquatic ecosystem.
Our research on the Mackenzie Delta represents an on-going and long-term program with the ultimate goal of developing an ecosystem model to predict the response of arctic delta ecosystems to the combined stresses (e.g. climatic warming, increasing sea level, and increasing UV-light) of global change. Each of these stresses may not necessarily cause the system to respond the "same way", so it is necessary to determine the strength and direction of responses to the individual stresses to figure out what may happen to the system as a whole.
We have only begun to understand the basic the ecology and hydrology of this system. Several graduate thesis projects have been recently completed. These results have raised questions that should be further investigated. There are also a variety of other research questions that need to be answered to develop an ecosystem model, and which could form the basis for thesis projects for incoming graduate students. Examples include (among many other possibilities) studies of lake hydrology, aquatic food web configurations and nutrient dynamics, underwater UV-effects on organisms and DOC, flood-driven dynamics of aquatic habitat for fish and aquatic waterfowl. The International Polar Year has lead to recent expansion of our Mackenzie Delta research via a collaborative project IPY-SCARF. We welcome inquiries from post-doctoral candidates who are interested in ecosystem modeling.
Squires, M., L. Lesack, R. Hecky, S. Guildford, P. Ramlal, and S. Higgins. 2009. Primary production and carbon dioxide metabolic balance of a lake-rich arctic river floodplain: Partitioning of phytoplankton, epipelon, macrophyte, and epiphyton production among lakes of the Mackenzie Delta. Ecosystems 12:853-872. doi:10.1007/s10021-009-9263-3.
Emmerton, C., L. Lesack, and P. Marsh. 2007. Lake abundance, potential water storage, and habitat distribution in the Mackenzie River Delta, western Canadian Arctic. Water Resour. Res. 43: W05419, doi:10.1029/2006WR005139.
Squires, M., & L. Lesack. 2003. Spatial and temporal patterns of light attenuation among lakes of the Mackenzie Delta. Freshwater Biol. 48:1-20.
Carson, M.A., F.M. Conly, and J.N. Jasper. 1999. Riverine sediment balance of the Mackenzie Delta, Northwest Territories, Canada. Hydrol. Process. 13:2499-2518.
Lesack, L.F.W., P. Marsh, and R.E. Hecky. 1998. Spatial and temporal dynamics of major solute chemistry among Mackenzie Delta lakes. Limnol. Oceanogr. 43:1530-1543.
Rouse, W., M. Douglas, R. Hecky, A. Hershey, G. Kling, L. Lesack, P. Marsh, M. McDonald, B. Nicholson, N. Roulet, and J. Smol. 1997. Effects of climate change on the freshwaters of arctic and subarctic North America. Hydrological Processes 11:873-902.
Marsh, P., and L.F.W. Lesack. 1996. The hydrologic regime of perched lakes in the Mackenzie Delta: Potential responses to climate change. Limnol. Oceanogr. 41:849-856.
Marsh, P. and M. Hey. 1989. The flooding hydrology of Mackenzie Delta lakes near Inuvik, NWT, Canada. Arctic 42:41-49.
Mackay, J.R. 1963. The Mackenzie Delta Area, NWT, Canada. Canadian Department of Mines and Technical Surveys, Geographical Branch Memoir No. 8, 202pp.
More publications - Here
