Seas surrounding an archipelago near the tip of the Antarctic Peninsula are richer in animal life than the Galapagos Islands, scientists said on Monday. Their findings challenge the notion that tropical regions are more rich in species than the poles.
Much less is known about the South Orkney islands than the tropical islands that helped to shape Charles Darwin’s thoughts about natural selection on his Beagle voyage.
But according to a study published on Monday by The Journal of Biogeography, the sea around them is teeming with a huge variety of life, disproving the notion that chilly polar waters have a much poorer variety of fauna.
“There has been a long-held belief that the tropics are rich and the polar regions are poor and mid-latitudes are somewhere in between,” said David Barnes at the British Antarctic Survey, who led the study, part of the international census of marine life. “This is the first time we’ve been able to actually look at the fauna of a polar archipelago — it is not actually that poor at all.”
Barnes said the reason for carrying out the survey was to establish a baseline from which changes in biodiversity due to global warming could be judged.
“This is in the part of the world with fastest change in terms of temperature,” he said.
The Antarctic Peninsula has experienced warming of 3ºC over the past 50 years.
“If you don’t know what the fauna is at any one point it is very difficult to detect either species moving in or species moving out,” he said.
The survey recorded 1,224 species in 50 different biological classes. The team discovered five new species and one genus — the biological category that is higher than species — that was new to science.
The new discoveries are all sea mosses or isopods (woodlouse-like animals), but they have not been given names yet.
The team also scoured reports from scientific expeditions and scientific literature going back decades to find every mention of species observed in the region, in an attempt to create the most complete and authoritative list of creatures found there.
Barnes’ team had to brave biting winds that frequently stopped them working, and watch for attacks by orcas and leopard seals. If either predator came near they had to climb on to the British Antarctic Survey’s royal research vessel James Clark Ross or scramble to shore.
“Although that sounds dramatic, weather is a far bigger issue,” Barnes said. “It stops us working far more and makes our work far more hazardous ... Sometimes it’s much warmer under the water — it’s only minus 1.5 [degrees Celsius]!”
Once under water, the view is spectacular, Barnes said.
“I don’t think I’ve been anywhere where you can see so many different types of major groups of animals,” he said.
As well as diving in the shallows, they also trawled the sea bottom to a depth of 1,500m using nets and a special sled with a sieve that held everything bigger than 0.3mm.