Please select your home edition
Edition
X-Yachts AUS X4 728 - 3

Unknown mechanism which breaks up tabular icebergs at sea discovered

by British Antarctic survey/BBC Operation Iceberg on 2 Nov 2012
Operation Iceberg BBC
A previously unknown mechanism by which large tabular icebergs break up out at sea, as part of a study carried out on the Peterman Iceberg in Baffin Bay over the summer, has been discovered by an international team of scientists. Scientists observed that the gradual creation of a huge underwater ice foot produced so much buoyancy that it broke large chunks off the main iceberg thus causing the iceberg to slowly disintegrate. This discovery was captured on camera as a film crew followed the expedition for Operation Iceberg, a two part BBC Two series going out this week.

Scientists have long assumed the decay of icebergs was either caused by wave action physically splitting them apart, or by warmer sea water gradually melting them. The truth now appears to be an interesting combination of factors. During the arctic expedition, scientists found that warm surface water, aided by wave action, erodes a deep notch around the edge of the iceberg. This notch is at water level, and the unsupported ice above the notch quickly sloughs away. Over time this creates a large underwater 'ram' or ice foot sticking out which is protected by colder, deeper water. This underwater ram creates so much buoyant upwards pressure that it finds a weak point within the iceberg which then snaps off. This can be a sizeable chunk of ice. During filming for Operation Iceberg, camera crews and scientists were aboard the iceberg when a chunk of ice, 200m by 50m, broke off in this way.


Dr Keith Nicholls of the British Antarctic Survey was on the two week expedition. He argues that the notch is the key start to this process. In the programme he says: 'The reason this iceberg is breaking up really fast in front of us is all about what’s happening at the wave cut in the warm water layer right at the surface.'

Also on the expedition was one of the world leading experts on ice science, Prof Peter Wadhams of Cambridge University, who believes their observation of the process is unique: 'We have discovered a new mechanism. People don’t normally sit beside melting icebergs in a ship. Normally when they come across an iceberg they give it a wide berth. So in a way, we’re the first people to be doing it.'

Alon Stern of New York University was responsible for taking the temperature measurements of the sea water around the iceberg, including key data gathered by the BBC’s dive team. These readings confirmed that the deeper water measured -1.5 degrees Celsius, and was therefore able to protect the ice foot from melting.

Understanding the mechanism by which icebergs break up is important for shipping in the North Atlantic. It is also becoming clear that because of climate change, the number of tabular icebergs in Arctic seas is increasing. Keith Nicholls added: 'In recent years we’ve been seeing a lot more big tabular icebergs come off the Greenland ice sheet and they’re now ending up in Baffin Bay. That’s a change and the only reason that can change is because the climate around Greenland is changing.'

To watch the team in action, tune into Operation Iceberg, at 9pm on BBC Two on Tuesday 30th of October and Thursday first of November.

You can read Dr Keith Nicholls' blog here.

http://www.antarctica.ac.uk/" target="_blank">British Antartic Survey website

Doyle Sails NZ - Never Look BackSchaefer 2016 Ratchet Block 660x82Harken and Fosters

Related Articles

Prototype aims to take on the Garbage Patch
A prototype aimed at achieving 'the largest clean-up in history' is deployed in the North Sea. As scientists look to find a way to rid the infamous Great Pacific Garbage Patch of thousands of tonnes of waste plastic, a prototype aimed at achieving 'the largest clean-up in history' is deployed in the North Sea.
Posted on 7 Jul
Marine Sustainability Conference with an expanded environmental theme
The event will not only revisit the dismantling and responsible recycling of leisure craft, but also engage in debate The event will not only revisit the dismantling and responsible recycling of leisure craft, but also engage in debate about whether the Boating Industry can effectively embrace the ‘Circular Economy’ and how it can interact with the environmental desirability of ocean and waterway conservation.
Posted on 27 May
Puteri Harbour Marina receives Level 3 Clean Marina Accreditation
The International Clean Marina Program is a voluntary accreditation program for marinas, yacht clubs, and boat clubs. Puteri Harbour is located at Iskandar Puteri, the narrow-most point along The Straits of Johor separating Singapore from the Asia continent. The prestigious waterfront development offers three marinas - public, mega yacht and a private marina - designed to cater to the sailing community.
Posted on 15 Apr
11th Hour Racing requests proposals to improve ocean health
Through the platform of sailing, 11th Hour Racing aims to increase our understanding of current threats to our oceans. Through the platform of sailing, 11th Hour Racing aims to increase our understanding of current threats to our oceans, find solutions to the challenges that impact marine resources, and promote stewardship of the seas.
Posted on 4 Apr
Seabin and Poralu Marine announce partnership + Video
Seabin Pty Ltd., through its branch The Seabin Project, aims to fight against water pollution Created by two Australians Andrew Turton, ocean lover, sailor, boat builder and Pete Ceglinski, industrial designer and surfer, Seabin Pty Ltd., through its branch The Seabin Project, aims to fight against water pollution
Posted on 20 Mar
Reef sharks take small bites
Coral reef sharks eat prey that are smaller than a cheeseburger Sharks have a reputation for having voracious appetites, but a new study shows that most coral reef sharks eat prey that are smaller than a cheeseburger
Posted on 20 Mar
Suburbs to Sea - Stopping litter at the source
Over sixty people gathered at Point Cook Community Centre for a special ‘Movies and Muffins’ night to learn about litter Over sixty people gathered at Point Cook Community Centre recently for a special ‘Movies and Muffins’ night to learn about litter and its impact on the environment as part of Wyndham City’s Green Living Series.
Posted on 18 Mar
Cyclone Winston Relief Fund – Help the people of Fiji
Sea Mercy is sending volunteer fleet of small and large vessels, loaded with shelter, food and medical supplies to Fiji. Sea Mercy is once again sending our volunteer fleet of small and large vessels, loaded with shelter, food, water and medical supplies and teams to Fiji.
Posted on 27 Feb
Land Rover BAR partners with Seabin to clean the oceans + Video
Recent research shows that between 5m and 12m tonnes of plastic find their way into the ocean every year. Recent research shows that between 5m and 12m tonnes of plastic find their way into the ocean every year. This is adding rapidly to the five trillion pieces - weighing around 270,000 tonnes - that are calculated to already be polluting the world's seas and oceans. Some estimates show that by 2050 the weight of plastic is likely to outweigh that of fish.
Posted on 23 Feb
Eco-warriors Sea-Bin crowd sharing critical stage with nine days to go
The automated marina cleaning SeaBin project has raised 86% of their target with 9 days left. The automated marina cleaning SeaBin project has raised $198,020 of $230,000.00 with nine days left on their Indiegogo crowdfunding platform, but they need more help now.
Posted on 29 Dec 2015