The Ross Sea is one of the world’s most ecologically intact, least-polluted nearshore ecosystems and is a global treasure. A deep bay found in the Southern Ocean, its most southerly portion is covered by the thick, permanent Ross Ice Shelf that is roughly the size of France.
The remainder of the sea is covered with much thinner sea ice that forms when seawater freezes during the southern autumn and winter, but in spring and summer, the addition of sunlight produces phytoplankton and Antarctic krill. Krill is the foundation species on which the food chain supports squid, Antarctic silverfish, emperor penguins, Weddell seals and blue whales. In fact, the Ross Sea provides habitat for significant portions of the world’s population of Adelie and emperor penguins (32% and 26% respectively). Some of these, in turn, are hunted by leopard seals, sperm whales and killer whales.
The Ross Sea’s foodweb overall is in much the same state it has been for millennia, making it a living museum and laboratory. Historically, the only species hunted here were the blue whales, which are now very slowly recovering. But recently fisheries for Antarctic toothfish have been increasing, thus threatening to alter this previously intact food web. Scientists are concerned that this may undermine their last chance to study a relatively undisturbed food web to separate out the consequences of climate change from direct human impacts. Scientists are already concerned that climate change could dislodge the vast Ross Ice Shelf and reduce essential sea ice cover.
The Ross Sea and adjacent coastal seas are treated in international law as essentially high seas, due to the agreed suspension of territorial claims on the Antarctic continent.