Please select your home edition
Edition
Fever-Tree 728x90

Extensive ice cap once covered Sub-Antarctic Island of South Georgia

by University of Exeter on 18 Mar
This is James Clark Ross. British Antarctic Survey © http://www.antarctica.ac.uk
A new study reveals the Sub-Antarctic Island of South Georgia – famous for its wildlife – was covered by a massive ice cap during the last ice age. The results are published today in the journal Nature Communications. South Georgia, the remote UK territory where Sir Ernest Shackleton landed during his dramatic voyage from Antarctica to rescue the team of his Endurance expedition, is home to various species of penguins and seals, and has featured on documentaries including Frozen Planet and Planet Earth II.



The island’s unusual plant communities and marine biodiversity, which are protected within a large Marine Protected Area, have survived and evolved through multiple glacial cycles for tens or even hundreds of thousands of years. But a research team led by the University of Exeter has discovered that at the peak of the ice age, about 20,000 years ago, ice thickened and extended tens of kilometres from the island – far further than previously believed.

This would have driven its biological communities to small mountain and seabed refuges to survive. The researchers also found the ice has been sensitive to short-lived cooling and warming – growing and shrinking dramatically as the climate changed. “Although the island is small framed against Antarctica’s great ice sheets, the discovery of an extensive past ice cap on South Georgia is an important result,” said lead author Dr Alastair Graham, of the University of Exeter.

“The survival of ocean ecosystems is linked heavily to patterns of glaciation, so it is very interesting to know where and how sea-bed creatures lived through the ice age, and how the cycles of ice-cap change have influenced the biodiversity. Life must have really only survived at the edges, at and beyond the ice margins.'



“Our work also provides a key data point for ice sheet and climate models, which will now need to simulate a large ice field on South Georgia during the last ice age if they are to have confidence in their outputs.”

The team from the UK, Germany and Australia travelled to the island on British Antarctic Survey’s RRS James Clark Ross in 2012, and the German RV Polarstern in 2013 to carry out sonar mapping using sophisticated sonar technology mounted to the hulls of ice-breaking vessels.

They also used weighted gravity corers to retrieve samples of ancient sediment from the ice-carved troughs that radiate from the island to reveal past patterns of glacier expansion and melting. The researchers discovered hundreds of distinct ridges bulldozed into the seabed by glaciers, showing that – contrary to previous estimates – the ice extended across South Georgia’s vast continental shelf. Co-author Duanne White, from the University of Canberra, said: “Glaciers in the sub-Antarctic are retreating dramatically today, in response to an ever-warming atmosphere and ocean.

“It is perhaps unsurprising that South Georgia’s glaciers were sensitive to climate change in the past, but our work has really shown that they were dynamic and underwent big changes over geological time. Improving the history of glacier behaviour on South Georgia even further is now essential so that we have a long-term context for the alarming recession we are witnessing right now.”



Co-author Dominic Hodgson, from British Antarctic Survey, said: “The Sub-Antarctic is a region experiencing massive climate changes with rapidly shrinking glaciers and the loss of several ice caps in recent decades. Studying the longer-term history of glacial changes in the region is key to understanding the sensitivity of glaciers to climate change, and their impacts on biodiversity and species survival.”

The paper is entitled: “Major advance of South Georgia glaciers during the Antarctic Cold Reversal following extensive sub-Antarctic glaciation.”

The research was funded by the Natural Environment Research Council (NERC).

NaiadDoyle Sails NZ - Never Look BackZhik AkzoNobelb 660x82

Related Articles

Race for Water vessel and her crew make landfall in Cuba
13 days of sailing disrupted by a series of overly frequent encounters with plastic waste floating on the water surface. Thirteen days of sailing disrupted by a series of overly frequent encounters with plastic waste floating on the surface of the water according to the crew.
Posted on 24 Jul
Newport Rhode Island, social cruising continues...
After relaxed 50 mile passage we sailed into Newport Rhode Island arriving on schedule for much anticipated dinner date. After a relaxed 50 mile passage we sailed into Newport, Rhode Island, arriving on schedule for a much anticipated dinner date. Coming into the harbor we dodged beautiful schooners and even more beautiful 12 Meter Americas Cup boats, all carrying passengers on commercial harbor cruises. Newport just oozes sailing tradition, money and tourists.
Posted on 23 Jul
Maiden voyage for Mission Océan
Mission Ocean has sailed for the first time on the catamaran that is destined to become our HQ Mission Ocean has sailed for the first time on the catamaran that is destined to become our HQ, a platform for oceanographic research, a center of learning to raise awareness of marine pollution, and also our home for the next three years.
Posted on 22 Jul
ARC Baltic 2017 - Welcome to sunny but windy Visby!
On second Leg of ARC Baltic, 24 boats left Ronne on Friday 14th of July in early morning for a 200NM passage to Gotland On the second Leg of the ARC Baltic, the 24 boats left Ronne on Friday 14th of July in the early morning for a 200NM passage to Gotland, Visby harbour. After a day and overnight sail, the first boat Marevida arrived in Visby on Saturday morning followed by the rest of the fleet in the afternoon. The boats were berthed alongside main wall into town only few minutes’ walk from the historical centre.
Posted on 22 Jul
The Great New England Social Cruise - Part 2
Leaving Norwalk, we motor sailed against a 25 knot north easterly wind to reach shelter in New Haven, Connecticut. Leaving Norwalk, we motor sailed against a 25 knot north easterly wind to reach shelter in New Haven, Connecticut. Once again, this was a slightly disappointing harbor destination, however it did allow us to stage our way to the North East along Long Island Sound, in quite poor weather. Life looked better the next day when we arrived at the village of Noank
Posted on 22 Jul
2017 World ARC - Goodbye Vanuatu! Hello Coral Sea!
Thank you to the Yachting World Marina for hosting a very special stay in Port Vila, Vanuatu. Thank you to the Yachting World Marina for hosting a very special stay in Port Vila, Vanuatu. The World ARC fleet set off this morning at 10:00 am for Leg 7, destination Mackay, Australia. Vanuatu is an island paradise and the picture perfect setting did not disappoint this morning. Sea turtles even came to bid farewell to the fleet!
Posted on 22 Jul
Very social cruising in New England
An unplanned series of connections somehow linked up, to create a cruise through beautiful New England like no other. Since leaving New York City our cruising life has become extremely social. An unplanned series of connections somehow linked up, to create a cruise through beautiful New England like no other. We started with a visit to the New York Athletic Club Yacht Club, at Travers Island, Pelham, just north east of the city.
Posted on 22 Jul
Abandoned and derelict vessels in Florida and the Caribbean
Abandoned and derelict vessels (ADVs) are a marine debris problem in many places around the United States In this region, which boasts both beautiful weather and waters, a high number of recreational and commercial boaters unfortunately equals a high number of ADVs.
Posted on 21 Jul
Fun and games in Island of Moorea
Fortunately for us our very good Dutch friends Martin and Ellen are staying in French Polynesia for a while. We had a fun week on the beautiful Island of Moorea meeting many new Cruisers before the eighty odd boats participating in the Pacific Puddle Jump continued on to New Zealand and Australia. Fortunately for us our very good Dutch friends Martin and Ellen are staying in French Polynesia for a while. We are enjoying their company sharing meals, drinks and activities.
Posted on 21 Jul
August Rendezvous – 150th Anniversary of Confederation
This year, the BCA peeps get together to celebrate the 150th anniversary of Confederation! This year, the BCA peeps get together to celebrate the 150th anniversary of Confederation! So, think Canada Day, think red and white and dress up your boat in the most Canadian fashion – there will be a prize for the best decorated boat in the bay!
Posted on 20 Jul