Antarctic sea urchins show adapation to climate change

The Southern Ocean sea urchin (Sterechinus neumayer) is a slow-growing, long-lived invertebrate, essential for its role in grazing the detritus of other ocean animals in the benthic environment. A new study by scientists from the British Antarctic Survey (BAS) and Bangor University has revealed that this species may be resilient to climate change, showing an ability to acclimate to changing ocean temperatures and acidification.

Two hundred and eighty-eight sea urchins collected from the Antarctic Peninsula were transferred to aquaria at the BAS in Cambridge where they were monitored for two years under conditions replicating those predicted in the oceans for the turn of the century. Raised water temperature and lowered alkalinity levels had no impact on the growth rate of the sea urchins, and after 6-8 months their physiology had stabilised showing their acclimation to the new conditions.

The impacts of changing ocean conditions on the breeding of adult urchins and on the survivability rate of new born urchins were also investigated. After 6 months under the new conditions the number of larvae that spawned was significantly lower than the number that spawned at 17 months, showing not only adaptation to their new conditions over time but also highlighting the value of long-term experiments, particularly in animals that are slow to grow and mature. Dr Melody Clark of BAS said, “If we had stopped this experiment at three or even six months, we would have got very different results”.

The researchers also discovered that the eggs produced by individuals under the lowest pH levels were larger than those of the control group, possibly suggesting a higher investment of energy per egg as a method to increase the ability of generations to replace each other.

Dr Coleen Suckling of Bangor University said: “In the cold water of Antarctica metabolism is slowed which means that animals take longer to develop. This also means that the time it takes for them to mature and reproduce can be many years. So adaptation through generations might not be a reliable strategy to cope with rapid climate change, both processes occurring at almost similar time scales. Instead, if the animals are able to acclimate, then this might help them cope with future changes.”

Full paper: Suckling, C. C., Clark, M. S., Richard, J., Morley, S. A., Thorne, M. A. S., Harper, E. M., Peck, L. S. (2014), Adult acclimation to combined temperature and pH stressors significantly enhances reproductive outcomes compared to short-term exposures. Journal of Animal Ecology. doi: 10.1111/1365-2656.12316

Photo courtesy of British Antarctic Survey

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A nature writer and ecological advisor with wide experience of writing about wildlife and working in freshwater, marine and terrestrial environments. Website: Twitter: @DrPhoebeCarter

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