Tiny shifts in the timing of polar ice melting could create a "tipping point" with dire consequences for underwater ecosystems, new Australian research shows.
The study from the University of NSW and the Australian Antarctic Division found that as polar ice melts slightly earlier each year, the amount of sunlight reaching the sea floor will be exponentially increased.
This shows polar ecosystems may be even more sensitive to climate change than previously thought, according to Graeme Clark of the UNSW School of Biological, Earth and Environmental Sciences.
"Even a slight shift in the date of the annual sea-ice departure could cause a tipping point, leading to widespread ecosystem shifts," he said in a statement.
"On the Antarctic coast this may cause unique, invertebrate-dominated communities that are adapted to the dark conditions to be replaced by algal beds, which thrive on light, significantly reducing biodiversity."
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Sponges, moss animals, sea squirts and worms - all of which help filter water, recycle nutrients and provide a food source for fish and other creatures - could be lost.
The research predicts biodiversity on some areas of the polar seabed could be reduced by a third within decades.
For the study, to be published in the journal Global Change Biology, the team deployed light meters on the sea floor at seven sites near Casey Station in Antarctica.
They used cameras to photograph the coast every day for two-and-a-half years to determine sea-ice cover as well as surveying species living on sub-tidal boulders to see how communities varied with ice cover.
"Early melt that brings the date of sea-ice loss closer to midsummer will cause an exponential increase in the amount of sunlight reaching some areas per year," Dr Clark said.
