CASES 2002A central aim of the CASES field program is to study the fall and winter pre-conditioning of the Mackenzie Shelf/Amundsen Gulf ecosystem by the minimum fall and winter discharge of the Mackenzie River, and its spring and summer development in response to the intense freshet and the variable ice break-up. Because the area cannot be reached from southern ports until August when the ice retreats, the only possible way to achieve this is by over-wintering a research icebreaker in the area.
In preparation for this overwintering scheduled for 2003-2004, two expeditions were conducted in the fall of 2002. During the first expedition, eight mooring lines supporting current meters and sediment traps were moored in the study area as part of the 6 September to 24 September expedition of the CCGS Sir Wilfrid Laurier (Laurier 2002 cruise report). From 22 September to 14 October, the second expedition completed a multidisciplinary synoptic survey of the physical & biogeochemical properties of the study area onboard the CCGS Pierre Radisson (Radisson 2002 cruise report). During this 22-day expedition, 34 scientists sampled over 110 stations covering the Mackenzie Shelf & Amundsen Gulf area (see figure below). Continuous profiles of temperature, salinity, light transmittance, chlorophyll a fluorescence, oxygen & pH were conducted at all stations using a Seabird 911+ profiler. Sampling at Basic stations included the same profiles plus Rosette sampling of DOC, DIC, nutrients, total and fractionated Chl a, viral, bacterial, microbial and picoplankton densities at selected depths & plankton nets tows for the determination of zooplankton and juvenile fish densities. Operations at Full stations included Basic sampling plus bacterial, phytoplankton and zooplankton physiological rates, the deployment of floating sediment traps, box coring of bottom sediments, contaminants & thorium pumping profiles, UV profiles, ice algal sampling and satellite validation helicopter surveys. In between stations atmospheric conditions, heat & gaz fluxes and contaminant levels were continuously monitored along the ship’s track in the study area.
CASES 2002 - Map of the expedition of the Radisson
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