High Latitude Changes in Ice Dynamics and Their Impact on Polar Marine Ecosystems

Abstract

Polar regions have experienced significant warming in recent decades. Warming has been most pronounced across the Arctic Ocean Basin and along the Antarctic Peninsula, with significant decreases in the extent and seasonal duration of sea ice. Rapid retreat of glaciers and disintegration of ice sheets have also been documented. The rate of warming is increasing and is predicted to continue well into the current century, with continued impacts on ice dynamics. Climate-mediated changes in ice dynamics are a concern as ice serves as primary habitat for marine organisms central to the food webs of these regions. Changes in the timing and extent of sea ice impose temporal asynchronies and spatial separations between energy requirements and food availability for many higher trophic levels. These mismatches lead to decreased reproductive success, lower abundances, and changes in distribution. In addition to these direct impacts of ice loss, climate-induced changes also facilitate indirect effects through changes in hydrography, which include introduction of species from lower latitudes and altered assemblages of primary producers. Here, we review recent changes and trends in ice dynamics and the responses of marine ecosystems. Specifically, we provide examples of ice-dependent organisms and associated species from the Arctic and Antarctic to illustrate the impacts of the temporal and spatial changes in ice dynamics.

Southern Ocean Phytoplankton in a Changing Climate

“…Such changes can impose temporal asynchronies and spatial separations between grazers and their food, reducing grazer abundance, reproductive success, and altering the distributions of higher trophic levels (Moline et al, 2008). SO zooplankton use the sea ice as a refuge and food source in the winter (Daly, 1998;Murphy et al, 2007;Jia et al, 2016).…”

Site fidelity of Svalbard polar bears revealed by mark-recapture positions

“…Organisms that are strongly tied to a specific location or habitat may be particularly vulnerable in the face of changing resources and habitat availability (Laidre et al 2008). For polar bears, such changes could take the form of large interannual variability in sea ice conditions or long term reduction in summer sea ice cover due to a warming climate (Serreze et al 2007, Moline et al 2008). More detailed knowledge of polar bear fidelity to areas used during the critical spring season is needed if we are to evaluate the vulnerability of polar bears to these scenarios.…”

Evolution and Biodiversity in the Antarctic - The Response of Life to Change (Eba): Role and Legacy

“…The general trends are contradictory, but the western side of the Antarctic Peninsula is currently undergoing one of the fastest rates of change on the planet with significant biological consequences (Clarke et al 2007). Large reduction of annual sea ice causes migration of key fish species of the Antarctic trophic web (whose reproduction processes, being closely associated to sea ice, are upset), introduction of species from lower latitudes (such as myctophids) and altered assemblages of primary producers (Moline et al 2008). Wholesale extinctions of fish species will require many concomitant synergistic events, but species may become geographically or ecologically segregated marginalised (Anisimov et al 2007).…”