Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Deep-sea drilling to shed new light on the stability of the Antarctic Ice Sheet

25.01.2019

AWI geoscientists lead international IODP expeditions to the Antarctic Ocean

Over the next few months, geophysicists and geologists from the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research will gain unprecedented insights into the climatic history of the Antarctic Ice Sheet as part of the International Ocean Discovery Program (IODP). The experts will take part in three Antarctic expeditions on board the IODP drilling ship “JOIDES Resolution”, and will lead two of the three legs.


The US drilling ship JOIDES Resolution conducts expeditions in the frame of the International Ocean Discovery Program (IODP).

Bill Crawford, IODP

By collecting the drilled cores, the researchers hope to find evidence of how the ice masses of the Antarctic have reacted to sudden temperature climbs in past interglacial periods – information that is urgently needed in order to more accurately predict future sea-level rise. In terms of modelling, the behaviour of the Antarctic Ice Sheet is still considered one of the greatest question marks.

How will Antarctic ice masses respond to climate change, and to what extent will they contribute to sea-level rise? Climate researchers still don’t have a satisfactory answer to that question, partly because they lack information on how ice sheets have behaved in previous interglacial periods. Geophysicists and geologists from the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI) in Bremerhaven have now made it their goal to remedy the situation.

Over the next seven months, they will join three international expeditions to the Antarctic Ocean on board the US-based drilling ship “JOIDES Resolution”, and will serve as the scientific directors for two of the three expedition legs. These journeys will be undertaken as part of the International Ocean Discovery Program (IODP), which is dedicated to investigating the history of our planet and its climate on the basis of deep-sea cores.

The first expedition (IODP 379) started in Punta Arenas (Chile) on 23 January 2019, and takes the 29-member team of international researchers, accompanied by technicians, drilling experts and ship’s crew (altogether 125 people) to the Amundsen Sea – and with it, to the region broadly considered to be the Achilles heel of the West Antarctic Ice Sheet.

“Large sections of the West Antarctic Ice Sheet lie on land that is below sea level, which means these ice masses can easily be reached by warm ocean currents, and are therefore especially vulnerable to the effects of climate change,” explains Dr Karsten Gohl, an AWI geophysicist and one of the expedition’s two chief scientists.

Seeking signs of an eroding West Antarctic Ice Sheet

At the moment, those glaciers that empty into the Amundsen Sea are losing ice faster than all other ice streams in the Antarctic or in Greenland. Moreover, ice sheet simulations and sediment samples from the Ross Sea indicate that the ice masses of the West Antarctic retreated extensively during past interglacial periods – e.g., 3 million years ago in the Middle Pliocene, when the average global temperature was roughly 3 degrees higher than today.

In other words, it was essentially the same temperature as that predicted for the year 2100 if greenhouse-gas emissions remain constant.

Back then, the researchers believe, the West Antarctic Ice Sheet suffered a near-total collapse. However, there’s still no evidence to back their hypothesis. The planned deep-sea drilling missions in the Amundsen Sea are intended to change all that.

“By drilling down as far as 100 metres below the seafloor, we hope to find sediment deposits from the Pliocene and other warm epochs, where we should be able to see the remains of algae, foraminifera and other typical pelagic organisms. And these remains will prove that, in these warmer periods, there was little to no ice in West Antarctica,” says AWI geologist and expedition member Dr Johann Klages.

Finding these microfossils would also allow the researchers to reconstruct the past water temperatures, and to investigate which climate changes led to the retreat or decline of the West Antarctic Ice Sheet. For example, insights into how warm the deep-sea currents were back then are desperately needed.

The researchers plan to subsequently compare these historical values with current observations of deep-sea currents in the Amundsen Sea, in order to determine whether or not they could be considered the harbingers of a potential future collapse.

In addition, the experts hope to find evidence of increased iceberg occurrence. “As they drift, icebergs lose sand, gravel and pebbles that were trapped in their ice,” explains Johann Klages. “If we encounter coarse sand and gravel deposits when we drill, it will tell us that large quantities of ice broke off from the ice sheet in past interglacial periods and drifted through the Antarctic Ocean.”

Further, these stony deposits’ geochemical fingerprint would allow the researchers to identify the ice masses’ region of origin, and to reconstruct which glaciers lost the most ice in each respective interglacial period.

Drilling on a main route for icebergs

The participants in the second expedition (IODP 382), which will take them to the Scotia Sea from 20 March to 20 May, will rely on the same research principle. The waters between the Antarctic Peninsula and the Falkland Islands are considered both the main route for large icebergs and their graveyard. If the Antarctic did indeed lose substantial ice during the interglacial periods of the Pliocene and Pleistocene, there should be corresponding deposits in these waters – from West Antarctica and East Antarctica alike.

But if they are there, they’re quite far down; as AWI geologist and expedition member Dr Thomas Ronge explains: “At the planned drilling sites, the water is roughly 4,000 metres deep. We’ll have to drill for several days before we reach our target depth of 600 metres below the seafloor. Another important consideration: while we’re drilling, we have to hope that we don’t cross paths with any icebergs.”

For any other research ship, the moment an iceberg drew near, the drilling site would have to be abandoned – but not for the “JOIDES Resolution”: in the event the 143-metre-long drilling ship has to evade an iceberg, the borehole on the seafloor will be sealed with a specially designed, funnel-shaped borehole plug. The plug can be relocated later, so that, once the ship has successfully avoided the iceberg, the team can easily resume drilling, right where they left off.

In the world’s largest ocean current

The third leg of the expedition (IODP 383), which will be co-led by AWI geologist Dr Frank Lamy and the German climate researcher Gisela Winckler from Columbia University (USA), will take the ship to waters west of the Drake Passage, starting in late May. Once they’ve arrived there, in the southeast Pacific region of the Antarctic Circumpolar Current, the most powerful ocean current in the world, the researchers will have to drill 500 metres down into the seafloor in order to gather sediment samples from the Pliocene and Pleistocene.

“For our work, above all we’ll be considering the question of how wind and ocean currents in the Southern Hemisphere reacted to global warming trends in the past, and what major interactions there were between the atmosphere, the ocean, and the ice masses of the Antarctic,” relates Frank Lamy.

Once analysed and combined, the outcomes of the three expeditions are expected to allow the researchers to precisely reconstruct the ice masses’ behaviour during past interglacial periods. If all goes as planned, they will not only arrive at a much better grasp of one of the most central, yet poorly understood processes in the Earth’s climate system, but will also be able to more accurately predict the future development of the West and East Antarctic Ice Sheets. Taken together, the two sheets contain enough freshwater to raise the global sea level by roughly 58 metres.

The IODP is an international research programme in which the USA, Japan, China, South Korea, India, Brazil, New Zealand, Australia and 15 European countries, including Germany, are participating. The US-based IODP ship “JOIDES Resolution” can accommodate up to 50 researchers and 65 crewmembers. Its operations are financed by the National Science Foundation (USA), and by support organisations in all other IODP member states.

Notes for Editors

For further information on the International Ocean Discovery Program and the individual expeditions, please visit: http://iodp.tamu.edu/scienceops/expeditions.html

Printable images and graphics can be downloaded using the following link:
https://www.awi.de/en/about-us/service/press/press-release/deep-sea-drilling-to-...

Your academic contact partners at the Alfred Wegener Institute are:

IODP Expedition 379 to the Amundsen Sea:
• Chief Scientist Dr Karsten Gohl (tel.: +49(471)4831-1361; e-mail: Karsten.Gohl(at)awi.de)
• Dr Johann Klages (tel.: +49(471)4831-1574; e-mail: Johann.Klages(at)awi.de)
The expedition’s second chief scientist is the American Prof. Julia Wellner from the University of Houston (tel. +1(713)743-2887; e-mail: jwellner(at)uh.edu).

IODP Expedition 382 to the Scotia Sea
• Dr Thomas Ronge (tel.: +49(471)4831-2087; e-mail: Thomas.Ronge(at)awi.de)

IODP Expedition 383 to the Southeast Pacific / Circumpolar Current
• Chief Scientist Dr Frank Lamy (tel.: +49(471)4831-2124; e-mail: Frank.Lamy(at)awi.de)
The expedition’s second chief scientist is Prof. Gisela Winckler (tel.: +1(845)365-8756; e-mail: winckler(at)ldeo.columbia.edu).

At the AWI’s Communications and Media Relations department, Folke Mehrtens (tel.: +49(471)4831-2007; e-mail: media(at)awi.de) will be pleased to help you with any questions.

The Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI) conducts research in the Arctic, Antarctic and oceans of the high and mid-latitudes. It coordinates polar research in Germany and provides major infrastructure to the international scientific community, such as the research icebreaker Polarstern and stations in the Arctic and Antarctica. The Alfred Wegener Institute is one of the 19 research centres of the Helmholtz Association, the largest scientific organisation in Germany.

Ralf Röchert | idw - Informationsdienst Wissenschaft
Further information:
http://www.awi.de/

More articles from Earth Sciences:

nachricht Do ice cores help to unravel the clouds of climate history?
21.06.2019 | Leibniz Institute for Tropospheric Research (TROPOS)

nachricht News from the diamond nursery
21.06.2019 | Goethe-Universität Frankfurt am Main

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Fraunhofer IDMT demonstrates its method for acoustic quality inspection at »Sensor+Test 2019« in Nürnberg

From June 25th to 27th 2019, the Fraunhofer Institute for Digital Media Technology IDMT in Ilmenau (Germany) will be presenting a new solution for acoustic quality inspection allowing contact-free, non-destructive testing of manufactured parts and components. The method which has reached Technology Readiness Level 6 already, is currently being successfully tested in practical use together with a number of industrial partners.

Reducing machine downtime, manufacturing defects, and excessive scrap

Im Focus: Successfully Tested in Praxis: Bidirectional Sensor Technology Optimizes Laser Material Deposition

The quality of additively manufactured components depends not only on the manufacturing process, but also on the inline process control. The process control ensures a reliable coating process because it detects deviations from the target geometry immediately. At LASER World of PHOTONICS 2019, the Fraunhofer Institute for Laser Technology ILT will be demonstrating how well bi-directional sensor technology can already be used for Laser Material Deposition (LMD) in combination with commercial optics at booth A2.431.

Fraunhofer ILT has been developing optical sensor technology specifically for production measurement technology for around 10 years. In particular, its »bd-1«...

Im Focus: The hidden structure of the periodic system

The well-known representation of chemical elements is just one example of how objects can be arranged and classified

The periodic table of elements that most chemistry books depict is only one special case. This tabular overview of the chemical elements, which goes back to...

Im Focus: MPSD team discovers light-induced ferroelectricity in strontium titanate

Light can be used not only to measure materials’ properties, but also to change them. Especially interesting are those cases in which the function of a material can be modified, such as its ability to conduct electricity or to store information in its magnetic state. A team led by Andrea Cavalleri from the Max Planck Institute for the Structure and Dynamics of Matter in Hamburg used terahertz frequency light pulses to transform a non-ferroelectric material into a ferroelectric one.

Ferroelectricity is a state in which the constituent lattice “looks” in one specific direction, forming a macroscopic electrical polarisation. The ability to...

Im Focus: Determining the Earth’s gravity field more accurately than ever before

Researchers at TU Graz calculate the most accurate gravity field determination of the Earth using 1.16 billion satellite measurements. This yields valuable knowledge for climate research.

The Earth’s gravity fluctuates from place to place. Geodesists use this phenomenon to observe geodynamic and climatological processes. Using...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

2nd International Conference on UV LED Technologies & Applications – ICULTA 2020 | Call for Abstracts

24.06.2019 | Event News

SEMANTiCS 2019 brings together industry leaders and data scientists in Karlsruhe

29.04.2019 | Event News

Revered mathematicians and computer scientists converge with 200 young researchers in Heidelberg!

17.04.2019 | Event News

 
Latest News

For a better climate in the cities: Start-up develops maintenance-free, evergreen moss façades

25.06.2019 | Architecture and Construction

An ion channel with a doorkeeper: The pH of calcium ions controls ion channel opening

25.06.2019 | Life Sciences

Cooling with the sun

25.06.2019 | Power and Electrical Engineering

VideoLinks
Science & Research
Overview of more VideoLinks >>>