Environmental Conservation



Paper

Polar marine ecosystems: major threats and future change


Andrew Clarke a1c1 and Colin M. Harris a2
a1 British Antarctic Survey, High Cross, Madingley Road, Cambridge CB3 0ET, UK
a2 Environmental Research and Assessment, 5 The Footpath, Grantchester, CB3 9NE, UK

Abstract

This review of polar marine ecosystems covers both the Arctic and Antarctic, identifying the major threats and, where possible, predicting their possible state(s) in 2025. Although the two polar regions are similar in their extreme photoperiod, low temperatures, and in being heavily influenced by snow and ice, in almost all other respects they are very different. The Arctic Ocean is a basin surrounded by continental landmasses, close to, and influenced by, large populations and industrial activities. In contrast, the Southern Ocean is contiguous with all the other great oceans and surrounds a single land mass; Antarctica is remote from major centres of population and sources of pollution. Marine environments in both polar regions have been highly disturbed by fishing activity, but, in terms of pollution, some areas remain among the most pristine in the world. There are, however, both local and global pressures. Over the 2025 time horizon, the greatest concern for the Arctic is probably the ecological implications of climate change, particularly insofar as sea ice extent and duration are likely to be affected. Such changes are not expected to be as pronounced in the Southern Ocean over this time period, and concerns are related more to direct threats from harvesting of marine living resources, and the ability to manage these fisheries sustainably. In both polar regions, the capacity of marine ecosystems to withstand the cumulative impact of a number of pressures, including climate change, pollution and overexploitation, acting synergistically is of greatest concern.

(Received January 9 2002)
(Accepted October 30 2002)


Key Words: Arctic; Antarctic; oceanography; climate change; biological impacts; ozone depletion; pollution; circumpolar current; polar marine ecosystems.

Correspondence:
c1 Correspondence: Dr Andrew Clarke Fax: +44 1223 221259 e-mail: andrew.clarke@bas.ac.uk