ARCUS 14th Annual Meeting and Arctic Forum 2002

The North Water: An Arctic Ecosystem Poised for Change

Jody W. Deming^1
1School of Oceanography and Astrobiology Program, University of Washington, Box 357940, Seattle, WA, 98195, USA, Phone 206-543-0845, Fax 206-543-0275, jdeming@u.washington.edu

A decade of intensive research under the auspices of the International Arctic Polynya Program (IAPP) has resulted in large and very successful interdisciplinary studies of two major Arctic polynyas: the Northeast Water, which forms off the northeast coast of Greenland (77–81°N; 1991–1993 field program); and the North Water, which forms between Greenland and Canada's Ellesmere Island (76–79°N; 1997–1999 field program). The rich comparative database developed in the process has enabled recognition of key physical, biological, and biogeochemical features that determine whether a polynya ecosystem is rich or poor in overall productivity – able or not to support top predators, including human populations. The International North Water Polynya Study (NOW) in particular has revealed clear forcing factors and input terms (climatic and oceanic) required to generate and sustain a high-magnitude phytoplankton bloom over an unprecedented period (at these latitudes) of nearly six months (April to October). The tight coupling between this bloom and the higher trophic levels of the region, enabled by the precocious recruitment of zooplankton (essential prey for fish, birds, mammals), contributes to the North Water being arguably the most productive ecosystem in the Arctic and rivaling other regions of the global ocean.

These and other discoveries have caused the IAPP to develop a new approach to polynya research for the future: dedicated time-series studies on the decadal scale that can recognize and provide a solid basis for predicting the sources and effects of environmental change. Ideally, such work would go forward in multiple Arctic polynyas simultaneously; practically, the effort is proposed to begin in the North Water (to continue that begun through NOW). There, the contemporary signals – physical, biological and biogeochemical – are as strong and unambiguous as can be expected in a complex natural system; some of them appear poised for change. For example, the seasonal duration of the ice bridge (across Nares Strait), largely responsible for polynya formation (and considered responsive to hemispheric forcing), has been decreasing over the last decade. The moving polar front in the Arctic Ocean may also conceivably (and soon) alter the chemical properties (balance of silicate and nitrate) of the inflow waters to the polynya. A remarkable diversity of phytoplankton awaits the shift away from diatoms, should silicate become limiting; the response of higher trophic levels to an altered food base then emerges as an issue of prime concern. In promoting a new program of long-term time-series research on Polynyas in the Arctic's Changing Environment (PACE), the IAPP aims to help the scientific community and society at large to learn and gain from what these archetypal ecosystems of the Arctic have to teach us about our changing Earth and its resources.

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