A new study published in Frontiers in Marine Science has revealed that animals dependant on sea ice are likely to suffer most due to the predicted effects of climate change. However, it is expected that sea-floor predators and open water feeding animals such as starfish and jellyfish are likely to benefit from the phenomenon as it will open up new habitats for them.
“One of the strongest signals of climate change in the Western Antarctic is the loss of sea ice, receding glaciers and the break-up of ice shelves,” says Dr Simon Morley, lead author, based at the British Antarctic Survey (BAS), UK. “Climate change will affect shallow water first, challenging the animals who live in this habitat in the very near future. While we show that many Antarctic marine species will benefit from the opening up of new areas of seafloor as habitat, those associated with sea ice are very much at risk.”
Study co-author and seabird ecologist Mike Dunn adds, “We took a similar approach to risk assessments used in the workplace, but rather than using occupational safety limits, we used information on the expected impacts of climate change on each animal. We assessed many different animal types to give an objective view of how biodiversity might fare under unprecedented change.”
Crustaceans whose young feed on the algae growing on the seafloor were found to be of particular consequence, as the animals that feed on them are impacted. These include the Adèlie and chinstrap penguins and the humpback whale. The emperor penguin also scored as high risk because sea ice and ice shelves are its breeding habitat.
“Many of these species are the more robust pioneers that have returned to the shallows after the end of the last glacial maximum, 20,000 years ago when the ice-covered shelf started to melt and retreat,” explains Dr David Barnes, co-author of this research. “These pioneer species are likely to benefit from the opening of new habitats through loss of sea ice and the food this will provide.”
He continues, “Even if, as predicted for the next century, conditions in these shallow-water habitats change beyond the limits of these species, they can retreat to deeper water as they did during the last glacial maxima. However, these shallow-water communities will be altered dramatically – temperature-sensitive animals with calcium shells were scored as the most at risk if this happens.”
As more information becomes available, the researchers hope to improve their predictions.
Morley explains, “The next step is to assign weights to the factors and predicted impacts. For example, the temperature is a factor that has major effects on cold-blooded marine animals, but will it be more of a problem than the benefit from the loss of sea ice? It is very difficult to know until we have more data.”