The Mackenzie Delta covers an area about 1/3rd the size of Switzerland (~13,000 km2) contains 45,000 lakes, and is an important representative of low-elevation river deltas around the circumpolar arctic that may become affected by sea level rise and declining effects of spring ice-breakup. This delta is one of the biological "hot-spots" of the arctic, having disproportionately high productivity and high biodiversity relative to aquatic habitat on the surrounding arctic landscape, as is likely the case for the other large deltas along the Russian arctic coast. The Mackenzie Delta is home to large communities of fish, water fowl, shore-birds, and fur-bearing animals. Given the large number of birds using the delta, the Kendall Island Bird Sanctuary, a major nesting ground for waterfowl and shore-birds, was established in 1961. The communities of Inuvik, Aklavik, Fort McPherson, Tsiigehtchic, and Tuktoyaktuk use the delta for fishing, trapping, and hunting. In addition, the Mackenzie Delta contains two of the three production gas fields for the proposed Mackenzie Gas Project.
In addition to being an important ecosystem unto itself, the Mackenzie Delta has important biogeochemical effects on the Mackenzie River and the Beaufort Sea ecosystem. For example, the Arctic Ocean receives much higher river inflows than other ocean basins. These riverine fluxes of freshwater, nutrients, dissolved organic matter, and particulates have major implications for sea-ice formation, for driving the productivity of aquatic marine foodwebs, and for optical properties of ice-free areas and ice-pack margins. The Beaufort Shelf is strongly influenced by Mackenzie River outflows, and the strength of this influence has been historically amplified by extensive sea-ice that has limited the extent of summer open-water and greatly slowed the rate at which the nutrient-rich river waters are dispersed into the Arctic Ocean. Such restricted dispersion is responsible for creating a seasonal (during high river discharge) semi-freshwater lake ("Lake Mackenzie") each year that "floats" within the higher salinity Beaufort Shelf waters, and that is very high in microbial biodiversity. Because Mackenzie River water must pass through its lake-rich and highly productive delta prior to its exit at the coast, we expect the downstream delivery of important river-borne nutrients and carbon to the coastal region is significantly affected. However, this "delta-effect" and the general linkage between the river, delta, and coastal ecosystem is thus far very poorly understood, as is the case for the Russian rivers and their large lake-rich deltas.
Recent work has shown that over the past 30+ years, summer low-water levels in the Mackenzie Delta may have increased by an amount (0.3 m) equivalent to three times local sea level rise (0.1 m) over the same period. Such amplification of recent sea level rise has been unexpected and may be a result of enhanced storm surges in response to receding arctic sea ice or coastal backwater effects on the river flow. Other work suggests a recent decline in river-ice breakup effects in the delta that historically have been an important control on annual peak water levels. If these two changes in the system (via two differing global change mechanisms) are real, fish habitat in the delta will expand, overall biodiversity of the system may decline, and relative subsidence of the land-surface associated with future oil and gas extraction in the region could be substantially higher than expected.
In short, the Mackenzie Delta is an important arctic ecosystem that is poised to be altered via global change and economic development. Our ability to detect ongoing changes, and to predict future changes, is being advanced by our International Polar Year project IPY-SCARF (one component of a larger IPY Project, "Arctic Freshwater Systems". General goals for IPY-SCARF include: (1) implementing, refining, and testing an enhanced 1-D hydraulic model of river flow (capable of handling ice-jams and storm surge backflows) through the Mackenzie Delta channel network; (2) field investigations of real-time ice jams and measurements necessary for process-based modeling of ice jams at selected locations; (3) linking the hydraulic model to a model of storm surge effects from the Beaufort coast; (4) incorporating new results into long-term modeling of Mackenzie River flows and potential responses to climatic warming; and (5) improved nutrient characterization of the Mackenzie during breakup and open-water. Results will fill critical data gaps, allow correct quantification of freshwater and nutrient fluxes to the Beaufort Sea, and provide a practical tool for predicting water levels through the Mackenzie Delta and redistribution of important aquatic habitat, as climate continues to change, sea level rises, and arctic sea-ice recedes.
Dr. Lance Lesack - Lead-investigator - delta limnology and biogeochemistry - Simon Fraser University
Dr. Philip Marsh - Co-lead-investigator - delta hydrology - National Water Research Institute / Environ Canada
Dr. Faye Hicks - Coinvestigator - channel hydraulics modeling - University of Alberta
Dr. Spyros Beltaos - Coinvestigator - river-ice jamming observations - National Water Research Institute / Environ Canada
Dr. Terry Prowse - Coinvestigator - river-ice jamming - National Water Research Institute / Environ Canada
Dr. Joost Vander Sanden - Coinvestigator - satellite tracking of ice breakup - Canada Centre for Remote Sensing / NRCan
Dr. Will Perrie - Coinvestigator - storm surge modeling - Bedford Institute of Oceanography / Fisheries Oceans Canada
Steve Solomon - Coinvestigator - outer delta sea-ice interface - Bedford Institute of Oceanography / NRCan
Dr. Don Forbes - Coinvestigator - sea level effects and delta subsidence - Bedford Institute of Oceanography / NRCan
Dr. Arthur Roberts - Coinvestigator - airborne tracking of high-water dynamics - Simon Fraser University
Dr. Chris Hopkinson - Coinvestigator - lidar derived low-water topography - Applied Geomatics - Nova Scotia Community College
Dr. Al Pietroniro - Coinvestigator - river discharge modeling - National Water Research Institute / Environ Canada
Dale Ross - Coinvestigator - river gauging - Water Survey Canada / Environ Canada
Dr. Fred Wrona - Project Leader - National Water Research Institute / Environ Canada
Dr. Al Pietroniro - Co-Project Leader - National Water Research Institute / Environ Canada
Peter di Cenzo - Project Coordination - National Water Research Institute / Environ Canada
Chris Spence - Community Outreach - National Water Research Institute / Environ Canada
Rob Kent - Community Outreach - Water Science and Technology Office / Environ Canada
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.
Tank, S., L. Lesack, and R. Hesslein. 2009. Northern delta lakes as summertime CO2 absorbers within the arctic landscape. Ecosystems 12:144-157. doi:10.1007/s10021-008-9213-5.
Graydon, J., C. Emmerton, L. Lesack, and E. Kelly. 2009. Mercury in the Mackenzie River delta and estuary: Concentrations and fluxes during open-water conditions. Science of the Total Environment 407:2980-2988. doi:10.1016/j.scitoevn.2008.12.060.
Emmerton, C., L. Lesack, and W. Vincent. 2008. Nutrient and organic matter patterns across the Mackenzie River, estuary and shelf during the seasonal recession of sea-ice. J. Marine Systems. 74:741-755. doi:10.1016/j.jmarsys.2007.10.001.
Emmerton, C., L. Lesack, and W. Vincent. 2008. Mackenzie River nutrient delivery to the Arctic Ocean and effects of the Mackenzie Delta during open water conditions. Global Biogeochemical Cycles 22: GB1024, doi:10.1029/2006GB002856.
Lesack, L., and P. Marsh. 2007. Lengthening plus shortening of river-to-lake connection times in the Mackenzie River Delta respectively via two global change mechanisms along the arctic coast. Geophys. Res. Lett. 34: L23404,doi:10.1029/2007GL031656.
Manson, G.K., and S.M. Solomon. 2007. Past and future forcing of Beaufort Sea coastal change. Atmosphere-Ocean 45:107-122.
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.
Galand, P, C. Lovejoy, and W. Vincent. 2006. Remarkably diverse and contrasting archaeal communities in a large arctic river and the coastal Arctic Ocean. Aquat. Microb. Ecol. 44:115-126.
Carmack, E.C. and R.W. Macdonald. 2002. Oceanography of the Canadian shelf of the Beaufort Sea: A setting for marine life. Arctic 55(Supplement 1): 29-45.
IPY-SCARF - proposal to International IPY Program
Arctic Freshwater Systems - coordinated super-project funded via Federal IPY Program
Arctic Freshwater Systems = Canadian Polar Hydrological Cycle + Freshwater Biodiversity
Canadian Polar Hydrological Cycle = Related Canadian Hydrology Projects + IPY-SCARF
Arctic Hydra = Arctic Freshwater Systems + Related International Projects
Canadian Polar Hydrological Cycle - coordinated Canadian hydrology proposal
Freshwater Biodiversity - coordinated Canadian aquatic biodiversity proposal
Arctic Hydra - coordinated international proposal
Canadian IPY Secretariat - http://www.ipycanada.ca
Canadian Federal IPY Program - http://www.ipy-api.ca
International IPY Program - http://www.ipy.org