Thinning ice in West Antarctica is currently contributing nearly 10 per cent of global sea level rise and scientists have identified Pine Island Glacier (PIG) as a major source. As part of a series of investigations to better understand the impact of melting ice on sea level an exciting new discovery has been made.
Using Autosub (an autonomous underwater vehicle) to dive deep and travel far beneath the pine Island Glacier's floating ice shelf, scientists captured ocean and sea-floor measurements, which revealed a 300m high ridge (mountain) on the sea floor.
Pine Island Glacier was once grounded on (sitting on top of) this underwater ridge, which slowed its flow into the sea. However, in recent decades it has thinned and disconnected from the ridge, allowing the glacier to move ice more rapidly from the land into the sea. This also permitted deep warm ocean water to flow over the ridge and into a widening cavity that now extends to an area of 1000 km² under the ice shelf. The warm water, trapped under the ice, is causing the bottom of the ice shelf to melt, resulting in continuous thinning and acceleration of the glacier.
Lead author Dr Adrian Jenkins of British Antarctic Survey said, "The discovery of the ridge has raised new questions about whether the current loss of ice from Pine Island Glacier is caused by recent climate change or is a continuation of a longer-term process that began when the glacier disconnected from the ridge.
"We do not know what kick-started the initial retreat from the ridge, but we do know that it started some time prior to 1970. Since detailed observations of Pine Island Glacier only began in the 1990s, we now need to use other techniques such as ice core analysis and computer modelling to look much further into the glacier's history in order to understand if what we see now is part of a long term trend of ice sheet contraction. This work is vital for evaluating the risk of potential wide-spread collapse of West Antarctic glaciers."
Co-author Stan Jacobs adds: "Since our first measurements in the Amundsen Sea, estimates of Antarctica's recent contributions to sea level rise have changed from near-zero to significant and increasing. Now finding that the PIG's grounding line has recently retreated more than 30 km from a shallow ridge into deeper water, where it is pursued by a warming ocean, only adds to our concern that this region is indeed the 'weak underbelly' of the West Antarctic Ice Sheet. Increased melting of continental ice also appears to be the primary cause of persistent ocean freshening and other impacts, both locally and downstream in the Ross Sea."
Audrey Stevens, Tel: +44 (0)1223 221230; email: firstname.lastname@example.orgNOC Press Office:
Stunning broadcast-quality footage and stills of Antarctica, along with a copy of the full Nature Geoscience paper are available at: ftp://ftp.nerc-bas.ac.uk/pub/photo/PIG/
Images used should be credited to British Antarctic Survey
Nature Geoscience paper: Observations beneath Pine Island Glacier West Antarctica and implications for its retreat
Notes for editors:
Ice shelf - a thick, floating platform of ice that forms where a glacier or ice sheet flows down to a coastline and onto the ocean surface
Glacier - a mass of ice that moves over land
Ice core - cylinders of ice obtained by drilling into a glacier, which tell a story about past climate
Autosub is an AUV (Automated Underwater Vehicle), designed, developed and built at the National Oceanography Centre in Southampton with funding from the Natural Environment Research Council. Autosub3 has a maximum range of 400km and is powered by 5,000 ordinary D-cell batteries. The batteries are packed in bundles in pressure-tested housings. Either end of the seven-metre sub there are free-flooding areas where the payload of instruments are installed. It carries a multibeam sonar system that builds up a 3D map of the ice above and the seabed below. It also carries precision instruments for measuring the salinity, temperature, and oxygen concentrations in the sea water within the ice cavity, which are vital to understanding the flow of water within the ice cavity and the rate of melting. Autosub is 7m long and weighs 3.5 tonnes. Travelling at 6km hour it is capable of diving up to 1600m deep, and can operate for 72 hours (400 km) between battery changes.
Scientists worked aboard the US research vessel Nathaniel B Palmer.
British Antarctic Survey (BAS), a component of the Natural Environment Research Council, delivers world-leading interdisciplinary research in the Polar Regions. Its skilled science and support staff based in Cambridge, Antarctica and the Arctic, work together to deliver research that underpins a productive economy and contributes to a sustainable world. Its numerous national and international collaborations, leadership role in Antarctic affairs and excellent infrastructure help ensure that the UK maintains a world leading position. BAS has over 450 staff and operates five research stations, two Royal Research Ships and five aircraft in and around Antarctica.
Lamont-Doherty Earth Observatory (LDEO), a member of Columbia University's Earth Institute, is one of the world's leading research centres seeking fundamental knowledge about the origin, evolution and future of the natural world. More than 300 research scientists study the planet from its deepest interior to the outer reaches of its atmosphere, on every continent and in every ocean. From global climate change to earthquakes, volcanoes, non-renewable resources, environmental hazards and beyond, Observatory scientists provide a rational basis for the difficult choices facing humankind in the planet's stewardship. www.ldeo.columbia.edu
The National Oceanography Centre (NOC) is a new, national research organisation that went live on 1 April 2010. NOC will work in partnership with the UK marine research community to deliver integrated marine science and technology from the coast to the deep ocean.
NOC brings together into a single institution NERC-managed activity at the National Oceanography Centre, Southampton, and the Proudman Oceanographic Laboratory in Liverpool. NOC will work in close partnership with the wider marine science community to create the integrated research capability needed to tackle the big environmental issues facing the world. Research priorities will include the oceans' role in climate change, sea-level change and the future of the Arctic Ocean.
The NERC royal research ships RRS James Cook and RRS Discovery are based at NOC in Southampton, as is the National Marine Equipment Pool, which includes Autosub and Isis, two of the world's deepest-diving research vehicles.
Heather Martin | EurekAlert!
Further reports about: > Antarctic Predators > Antarctica > Arctic > BAS > Earth's magnetic field > Environment > Environment Research > Geoscience > Glacier > Island > Lamont-Doherty > Nature Geoscience > Nature Immunology > Observatory > Oceanography > Pine > Pine Island Glacier > West Antarctica > ice sheet > oxygen concentration > renewable resource > sea level rise
NASA examines newly formed Tropical Depression 3W in 3-D
26.04.2017 | NASA/Goddard Space Flight Center
Early organic carbon got deep burial in mantle
25.04.2017 | Rice University
More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.
Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...
Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.
"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...
The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.
Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...
The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...
Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.
Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...
20.04.2017 | Event News
18.04.2017 | Event News
03.04.2017 | Event News
26.04.2017 | Materials Sciences
26.04.2017 | Agricultural and Forestry Science
26.04.2017 | Physics and Astronomy