Arctic Change: Impacts on Marine Ecosystems Services

The highly dynamic and thermodynamic ice sheet that covers the Arctic Ocean and its' ancillary seas dictates biological productivity and carbon fluxes over 15 millions km2 (or 4.2%) of the global ocean surface. As far as we know, the arctic ice cover has persisted for at least the last 3.7 MA and likely longer, allowing a unique flora and fauna to evolve and adapt to some of the most extreme environmental conditions at the surface of our planet. The resulting low-diversity ecosystem of highly specialized organisms is threatened by the on-going shrinking of its icy biota. Beyond the charismatic Polar bear, intriguing organisms (many of them newly discovered), ranging in size from the ice-adapted microbes and their viruses to the ice-dwelling Polar cod and Boreal whale, will be impacted by the on-going regression of the ice, many negatively, some positively. In the short term (until 2050?) the relaxation of the severity of arctic conditions is expected to increase productivity and carrying capacity of the ecosystem, to the benefit of existing populations. However, in the longer term (by the end of the century?), the lengthening of the ice-free season on the Shelves, the dismissal of the perennial Central ice pack, the warming and mixing of the surface layer, and the intensifying penetration of Atlantic Water into Arctic basins could spell the rapid displacement of Arctic specialists by Atlantic (and Pacific) generalists. This Atlantification of the Arctic Ocean will boost its overall biological productivity and the services provided by its ecosystems, at the cost of a major loss of biodiversity.