Please select your home edition
Edition
Zhik ZKG

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).

Zhik Isotak Ocean 660x82Doyle Sails NZ - Never Look BackBarz Optics - Kids range

Related Articles

Operation V-Berth
Last year, our winter project was to upgrade our electrical system. This year we decided to insulate the V-berth The last festive season we were so lucky to have an opportunity to house sit: central heating, washer and dryer, and a full kitchen. As a live aboard, these are huge luxuries in life! Of course, when we’re not living on the boat is the perfect time to do work on the boat. Last year, our winter project was to upgrade our electrical system. This year we decided to insulate the V-berth.
Posted on 25 Mar
Crew released from Merchant Vessel hijacked off Somali since 2012
On March 16 2017 the crew of the MT ARIS 13, a tanker vessel, was released from Somali pirate hands On March 16 2017 the crew of the MT ARIS 13, a tanker vessel, was released from Somali pirate hands due to the efforts of the Puntland Maritime Police Force (PMPF). The entire crew is reported unharmed. Under the care of the PMPF, the MT ARIS 13 is now proceeding to the Somali port city of Bosasso. On 13 March, pirates hijacked the vessel en route to Mogadishu from Djibouti.
Posted on 25 Mar
Port Townsend to New Zealand - Small boat big seas
Did you ever wonder what it might be like to sail across the Pacific (North and South) in a 24 foot sailboat? Did you ever wonder what it might be like to sail across the Pacific (North and South) in a 24 foot sailboat? Well, if you had attended the BCA Calgary Chapter February Club Night last week, you would have found out. Karen Sullivan and Jim Heumann provided us with an evening of insight and humour with the presentation of their voyage from Port Townsend, Washington to New Zealand and back again.
Posted on 25 Mar
Coast Guard joins Arctic stakeholders in historic forum
U.S. Coast Guard Commandant Adm. Paul Zukunft joined leaders representing eight coast guards of Arctic nations U.S. Coast Guard Commandant Adm. Paul Zukunft joined leaders representing eight coast guards of Arctic nations in signing a joint statement Friday. The statement adopts doctrine, tactics, procedures and information-sharing protocols for emergency maritime response and combined operations in the Arctic. The Arctic Coast Guard Forum is an operationally-focused, consensus-based organisation...
Posted on 24 Mar
Docking strategies – How to build your docking skills with Rick Ellis
You will grow new skills and turn your boat handling and communication from stress to success. Do you find some docking conditions challenging? Whether you are a single-handed sailor, an inexperienced crew or a confident helmsman, you will grow new skills and turn your boat handling and communication from stress to success. Instructor Rick Ellis, who also delivers BCA’s very popular Psychology of Voyaging workshops, lends his years of boating experience...
Posted on 24 Mar
X-Yachts advisory board announces ambitious strategy plan
X-Yachts now has three unique and different ranges. All three lines will be further developed and refined. Catering for a complete cross section of sailors prioritising Superb Sailing Pleasure, X-Yachts now has three unique and different ranges. All three lines will be further developed and refined.
Posted on 24 Mar
Three days of festivities in Lorient for the Race for Water Odyssey
Three days of festivities are planned in La Base, Lorient, to celebrate the start of the five-year expedition. To mark the occasion, Race for Water will welcome the general public on board on Saturday April 8, with 45-minute guided tours.
Posted on 23 Mar
Choosing for offshore cruising at the Bluewater Weekend
The ARC Bluewater Weekend is a truly unique combination of all three and more still. More than just a boat show, more than a seminar, and more than simply a cruiser rendezvous; the ARC Bluewater Weekend is a truly unique combination of all three and more still. Designed to encourage visitors think about all aspects of living their bluewater dream, the Bluewater Weekend is a chance to view a wide range of offshore cruising boats to suit all budgets, and meet experts...
Posted on 23 Mar
Dig under way for Matthew Flinders in old London cemetery
London has a long history of digging up burial grounds to lay rail lines. Sometimes it has done so with respect London has a long history of digging up burial grounds to lay rail lines. Sometimes it has done so with respect, but other times it has left behind – in the gruesome words of famous English author Thomas Hardy - 'human jam'. One body that may be disturbed in the name of progress is recognisable to every Australian – explorer Matthew Flinders, the first person to circumnavigate, Great Southern Land
Posted on 23 Mar
Coast Guard to host leaders from eight Arctic nations in Boston
The Arctic Coast Guard Forum is a consensus based organization with the purpose of leveraging collective resources The U.S. Coast Guard will host an eight-nation Arctic Coast Guard Forum Principals Meeting March 22-24 at the U.S. Coast Guard Base Boston in Boston. The Arctic Coast Guard Forum is an operationally-focused, consensus based organization with the purpose of leveraging collective resources to progressively foster safe, secure and environmentally-responsible maritime activity in the Arctic.
Posted on 22 Mar