Antarctic Sea Ice Breakup Has Potential To Substantially Alter Ocean Food Chain - Science Daily

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Despite the icy cold and darkness, beneath the frozen surface of the sea in Antarctica thrives a rich and complex array of plants and animals. But what will happen to all those creatures if global warming reduces the ice-cover, as is predicted for coming decades?

UNSW marine ecologists Dr Emma Johnston and Graeme Clark have been working with the Australian Antarctic Division to survey marine communities along the striking coast of Wilkes Land, east Antarctica. It's now clear that ice plays a major role in the ecology of shallow Antarctic marine systems, by reducing light penetration to the waters beneath.

The team has found marked differences in the composition of marine communities along a gradient of ice-cover. “Protected areas subject to prolonged ice-cover are dominated by an invertebrate filter-feeding community of sponges, worms and anemones,“ says Dr Johnston.

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In more exposed areas of the coast, however, ice breaks out early in the summer and canopy-forming algae that rely on light are dominant. “If global climate change results in more frequent ice-breakout and reduced ice-cover then these unique protected shallow-water invertebrate communities are likely to be out-competed by algae,” says Dr Johnston.

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http://www.sciencedaily.com/releases/2007/02/070207190309.htm