New life found at the bottom of Antarctic seas
25 January 2018
A massive survey of life in the freezing seas around Antarctica has shown that they harbour many more animals than previously thought.
The discovery is significant because scientists think the polar seas are particularly vulnerable to climate change.
Dr Adrian Glover, a deep-sea researcher at the Museum and a co-author of the study, says, 'We are used to thinking of the Antarctic as low in biodiversity, a frozen wilderness where life struggles to survive. But this study shows there are far more animals there than we previously thought.
'In the remote Amundsen Sea, more than half the species we recovered from the seafloor were new to science.'
The specimens in the study were collected during two expeditions, in 2006 and 2008, by the British Antarctic Survey's research ship the RRS James Clark Ross.
The scientists searched for creatures that live on the ocean floor at 13 locations in the Scotia and Amundsen seas. These areas are rarely explored by scientists because they're remote and covered in sea ice for most of the year.
Over the two trips, the expedition teams took 58 samples at depths ranging from 200 to 1,500 metres.
Sorting the gigantic harvest of specimens
Almost 265,000 animals were collected, including worms, molluscs and tiny crustaceans. It took four years for scientists at a variety of institutions to sift through and carefully sort the specimens.
Scientists at the Museum took on the job of examining a group called polychaete worms.
Also known as bristle worms, they are one of the most common marine organisms. There are more than 10,000 known species with a variety of lifestyles, although most live on or in the ocean floor.
Lead author of the study, Lenka Neal, identified the specimens using high-resolution microscopy, supported by DNA data for some species.
She says, 'Polychaetes are notoriously difficult to identify, and there are no field guides to these remote regions. But they are critically important in the Antarctic ecosystem, being the most abundant and diverse invertebrate organisms there.
'Understanding the Antarctic food chain, from plankton to whales, requires us to study and understand the incredible diversity of seafloor organisms.'
Discovering new species
Museum scientists examined almost 17,000 polychaete worms and identified 307 species. Remarkably, this now represents almost half the total known Antarctic polychaete diversity.
The number of species they found varied wildly from site to site, depending on the location and ocean depth. Some locations some supported a wide range of species, and others far less.
Dr Glover says, 'One major conclusion we have come to is that the Antarctic shelf is a unique habitat. It is influenced by, but fundamentally different to, the surrounding deep sea. We need to understand further how the Antarctic ice sheets have influenced the whole shelf in recent geological past.'
The Antarctic is a fragile environment. The waters are particularly vulnerable to climate change because they are likely to warm quicker than other areas and experience more ocean acidification. Commercial fishing is also expanding in the region.
Many species are adapted to the cold water of the Southern Ocean and grow slowly, making it hard for them to adapt to changes.
Dr Glover says, 'Our data support the notion that some areas of the Antarctic are extremely high in biodiversity.
'We were encouraged that some of these hotspots of diversity, such as the South Orkney Islands, are also now being protected by new legislation.
'The rapid changes in Antarctica - such as the recent collapse at the Larsen C ice shelf - mean that we must act now to collect vital data on marine ecosystem change in the region.'
All the data and specimens collected are now housed in the Museum's collections.
They are an important resource for scientists investigating the past and future of the Antarctic ecosystem.
The Museum has made these vast new datasets available for other scientists to use on the new Data Portal. They have also preserved the physical samples, which can be used for DNA research.
The curation of this new dataset was led by Senior Curator Emma Sherlock.
She says, 'We are delighted to have been able to add more than 10,000 new polychaete specimens to our open-access collection. These specimens are vital baseline data in a region undergoing rapid change.'
Dr Glover adds, 'By linking together raw data, physical specimens, DNA data and our published conclusions in a fully open-access way, we have created a new template for Antarctic marine research.
'We hope that other researchers will use the data and samples to help increase our understanding of this still largely unexplored wilderness.'
- by Katie Pavid