Food web structure and biogenic carbon export on the continental shelves of the Arctic Ocean (review)

• Main Authors: Legendre,Louis, Rivkin, Richard B., Michel,Christine
• Format: Report
• Language: English
• Published: Departement de biologie, Universite Laval/Ocean Sciences Centre, Memorial University of Newfoundland/Departement de biologie, Universite Laval 1996
• Subjects: Arctic; Arctic Ocean; Memoirs of National Institute of Polar Research; Polar Research; Sea ice
• Online Access: https://nipr.repo.nii.ac.jp/?action=repository_uri&item_id=2272; http://id.nii.ac.jp/1291/00002272/; https://nipr.repo.nii.ac.jp/?action=repository_action_common_download&item_id=2272&item_no=1&attribute_id=18&file_no=1

The Arctic Ocean is circumscribed by the North American and Eurasian continents. These land masses have an extensive system of continental shelves which receive the outflow of several major rivers and are covered by sea ice for most of the year. In this paper, we propose that a unique combination and chronology of environmental conditions are responsible for the structuring of food webs and the concomitant patterns of biogenic carbon export on the Arctic Ocean continental shelves. First, we examine the general environmental characteristics of polar waters (extreme seasonal cycle of solar radiation and submarine irradiance, low temperature, seasonal ice cover), the specific conditions that exist on Arctic Ocean continental shelves (riverine inputs, shelf-basin exchanges), and the general structure of pelagic marine ecosystem as well as that typical of Arctic shelves. Second, we discuss the significance of the unique food web structure on Arctic shelves. Second, we discuss the significance of the unique food web structure on Arctic shelves with regard to biogenic carbon export to apex predators and sequestration at depth. We present evidence that the extensive shelf system and riverine inputs influence the structure and dynamics of Arctic marine food webs in four ways. First, the large freshwater runoff delivers particulate material and dissolved inorganic and organic nutrients, it lowers the salinity and favors the development of sea ice. Second, because of the extreme annual cycle of solar radiation, there is a brief pulse of primary production, which is often followed by periods of rapid sedimentation of particulate organic carbon. Third, because of low seawater temperature, there is slow oxidation of particulate organic matter in the water column and on the bottom. The latter provides a supply of organic and inorganic nutrients for the maintenance of a microbial trophic level in the water column. Low temperature may favor efficient transfer of microbial components towards larger pelagic grazers and, ...