As in the terrestrial case, there is an increase in subarctic species moving northward into the Arctic, with the potential for increased species competition and major ecosystem reorganization. The biodiversity of polar oceans is structured to a large extent by cold temperatures. The Antarctic Ocean has had low, stable temperatures for at least 8 million years, whereas the Arctic Ocean has been cold for only the last ~2.5 million years. In response, organisms in Antarctic waters appear to have lost much of their physiological ability to adjust to increased temperatures (Peck, 2005) compared to Arctic species. For example, the Antarctic notothenoid fishes, which are the most stenothermal animals known, die of heat death at temperatures above 4 °C (Somero and DeVries, 1967). Consequently, some workshop participants theorized that Antarctic marine species might be more susceptible to the effects of regional and global climate change than Arctic species.
In light of the regional warming trends observed in the polar marine environment, it is important to consider marine biodiversity in the context of long-term evolutionary processes in which the genetics of the organisms is modified in ways that allow them to adapt to the temperature environment and short-term pulsed events. Genomic approaches to identify the types of genetic mechanisms that provide organisms with the abilities to adapt to environmental change and, conversely, to understand what types of genetic limitations exist in stenotolerant organisms that possess very limited abilities to tolerate and acclimate to temperature changes, are needed to fully understand the effects that climate change will have on polar marine biodiversity.
Workshop participants commented on the possibility of increased human activity in the polar regions as a result of greater access and more open water days. Until the recent economic downturn, ecotourism was increasing significantly. Shipping across northern routes has started and is expected to increase as the number of ice-free days increases. Potential impacts from such activities include disturbance to wildlife and cultural resources from tourists, oil spills, discharge of gray and black water (sewage) from cruise ships, as well as the potential for invasive species and diseases into these remote and previously difficult to access regions. Natural resource development in the Arctic is likely to be one of the key drivers of marine activity in the future (Arctic Council, 2009). Approximately 13 percent of the world’s undiscovered oil may be found in the Arctic (Gautier et al., 2009) and oil and fuel spills are among the most significant