Antarctic marine life may grow faster in a warming world

British Antarctic Survey Press release - 31 August 2017

A team of scientists has discovered that a 1°C rise in local sea temperature has massive impacts on an Antarctic marine community. These new results are published this week (31 August) in the journal Current Biology, and enable researchers to better understand the biological implications of the future ocean warming predicted by the Intergovernmental Panel on Climate Change (IPCC).

 

By deploying heated panels on the seabed around Rothera Research Station, on the Antarctic Peninsula, the team observed that with a 1°C rise in sea temperature, predicted by the IPCC to occur before 2100, the growth of Antarctic seabed life nearly doubled. This is much greater than the long held expectation for biological responses to temperature. With a 2°C rise, however, the results are less clear as some species continued to grow faster whilst others had likely reached a limit.

 

Organisms on the seabed in Antarctica live in a very cold and stable environment where annual temperatures vary only between -2 and +1°C. The environment has been this cold for millennia, and so marine life has become highly adapted. Understanding how future environmental change will affect the polar biodiversity in the ocean is key, as species may either benefit from or be damaged by small changes in sea temperature.

Lead author Dr Gail Ashton, who led the project whilst at Rothera says:

 

“This is a deceptively simple and unambiguous experiment. By putting our test plates in the ocean and conducting the experiment there, we’ve changed almost nothing except the water temperature: not the food supply not light levels, nor the surrounding ecosystem. We can see the impact of temperature change very clearly and it’s quite dramatic.”

 

Researchers monitored the settlement and growth of organisms on the panels using high-resolution photography acquired by divers working in the frigid Antarctic water. Analysis of the photographs has provided clear visual evidence, which alongside the data reveal that with a 1°C rise in sea temperature, the Antarctic marine community experienced an unexpectedly high level of growth.

 

Dr Ashton, now at the Smithsonian Environmental Research Center in California, continues:

 

“Having spent most of my career working at temperate latitudes, the observable difference in communities warmed by just 1°C was quite a surprise”.

 

The animals that settled on the panels include colonial bryozoans and spiral tube worms, both common to seafloors globally. Increased growth may be a positive ecosystem response, nutrients would be more quickly available to species further up the food chain, while increased skeletal growth would increase carbon capture to the sea floor.  Species richness, the number of different species represented in a community, remained the same under warming, although diversity and evenness of the community was reduced. The overall dominance of the community by a single species of encrusting bryozoan (Fenestrulina rugula), gives an indication that this species would be one of the winners under future ocean warming. In this study it grew twice as fast in warmer conditions.

 

Dr Simon Morley, an ecophysiologist at BAS says:

 

“Such large changes in communities, in response to conditions that are forecast within our lifetimes, is quite remarkable. Much of the biodiversity in the oceans is attached to the sea floor and these communities are clearly susceptible to even small changes in their environment. Understanding which species will be the winners and losers is key as we try to   predict the impact of climate change on life in the ocean.”

 

ENDS

Issued by the Press Office at British Antarctic Survey.

Athena Dinar, Senior PR & Communications Manager, British Antarctic Survey, tel: +44 (0)1223 221 441; mobile: +44 (0)7909 008516; email: amdi@bas.ac.uk

Dr Gail Ashton tel: +1 (0) 415-435-3528, email: ashtong@si.edu

 

Notes to Editors:

Warming by 1°C drives species and assemblage level responses in Antarctica's marine shallows by Gail V Ashton, Simon A Morley, David KA Barnes, Melody S Clark, Lloyd S Peck is published by Current Biology Vol 27 Number 17.

 

Images are available for download from the British Antarctic Survey Press Office as above.

 

The Heated Settlement Panels Project is based at Rothera Research Station operating out of the Bonner research laboratory. Scientists and the Antarctic Marine Engineering Team (AME) developed a system of heated settlement panels. A small electric current is fed to a heating element on the underside of a standard settlement panel. This ensures that the thin layer of water overlying the panels is heated to 1 or 2°C above ambient temperatures, thus mimicking a warming ocean. Small encrusting animals settle on these panels, and scientists have been monitoring how fast they grow and compete with each other for space at different temperatures. The panels were deployed in the waters around Rothera and photos were taken at regular intervals over 2 years to determine how the marine communities would be affected under future climate change. This project is funded by NERC: reference NE/J007501/1 “Effects of warming on recruitment and marine benthic community development in Antarctica”.

 

Rothera Research Station, the largest British Antarctic facility, is a centre for biological research and a hub for supporting deep-field and air operations. Situated on Adelaide Island to the west of the Antarctic Peninsula, the site includes the Bonner research laboratory, offices and workshops and a crushed rock runway, hangar and wharf. The station operates throughout the year. In summer, the population peaks at just over 100 people, while during the winter months, from April to mid-October, a 22-strong team continues the science work and maintains Rothera’s infrastructure. Rothera supports a wide range of BAS, UK University and international collaborative science programmes including the Dirck Gerritsz laboratory that is operated by the Netherlands polar research programme.

 

Scientific diving at Rothera is used to support marine science projects. The diving science projects at Rothera are varied and demanding and are at the cutting edge of polar marine biology. There are two main categories of project, those associated with the long-term monitoring of the environment and specific shorter term studies. The dive programme continues year round with divers accessing the water through holes cut in the sea ice during the winter.

 

British Antarctic Survey (BAS), an institute of the Natural Environment Research Council (NERC), delivers and enables world-leading interdisciplinary research in the Polar Regions. Its skilled science and support staff based in Cambridge, Antarctica and the Arctic, work together to deliver research that uses the Polar Regions to advance our understanding of Earth as a sustainable planet. Through its extensive logistic capability and know-how BAS facilitates access for the British and international science community to the UK polar research operation. Numerous national and international collaborations, combined with an excellent infrastructure help sustain a world leading position for the UK in Antarctic affairs. For more information visit www.bas.ac.uk

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