Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Nordic seas cooled 500,000 years before global oceans

29.10.2015

The cooling of the Nordic seas towards modern temperatures started in the early Pliocene, half a million years before the global oceans cooled

The cooling of the Nordic Seas towards modern temperatures started in the early Pliocene, half a million years before the global oceans cooled. A new study of fossil marine plankton published in Nature Communications today demonstrates this.


This figure shows the evolution of Nordic sea surface circulation.

Credit: Stijn De Schepper

In the Pliocene, 5.3 to 2.6 million years ago, the world was generally warmer than today. The cooling of the oceans toward the modern situation started from 4 million years ago, but a new study now shows that the Nordic Seas cooled 500,000 year earlier.

Stijn De Schepper, researcher at Uni Research and the Bjerknes Centre for Climate research, has together with colleagues from the University of Bergen, the Alfred Wegener Institute in Germany and the Korea Polar Research Institute, investigated the fossil remains of microscopic marine plankton, especially dinoflagellate cysts, in two sediment cores from the Norwegian Sea and the Iceland Sea.

"We see that the dinoflagellate cyst assemblages underwent fundamental changes around 4.5 million years ago. Together with the simultaneous first occurrence of cool-water Pacific mollusks in Iceland, our results demonstrate that the Nordic Seas cooled significantly", De Schepper says.

Major ocean current changes

This new study and the earlier work on migration of Pacific mollusks into the Nordic Seas suggest that the Bering Strait was open at this time, and that cool water from the Pacific flowed into the Arctic. This cool water flowed southwards along East Greenland and into the Nordic Seas, where we started to see the same temperature and circulation pattern as we have today.

Today, the Nordic Seas surface waters are characterised by an east-west temperature gradient. The southernmost part of Greenland is at the same latitude as Bergen and Oslo in Norway, but the climate in Greenland is much cooler. The warm water near Scandinavia is brought northwards via the Norwegian Atlantic Current, a continuation of the North Atlantic Current, and is today responsible for the mild winter climate along the coast of Norway. Along east Greenland a cold water current known as the East Greenland Current flows southward and transports the major part of all exported Arctic sea ice.

Thermal isolation of Greenland

"Our study shows that a surface water temperature gradient was only established since 4.5 million years ago, when warm waters continued to flow along the Scandinavian coast and cool water entered the Nordic Seas along Greenland's east coast", De Schepper says.

In the early Pliocene the icecap on Greenland was restricted to mountain glaciers. The cool surface water that arrives from 4.5 million years ago in the western Nordic Seas isolates Greenland from the warmer water in the eastern Nordic Seas. This cool water likely leads to cooler temperatures in Greenland and the expansion of the Greenland ice sheet in the late Pliocene.

###

Timeline: https://cdn.knightlab.com/libs/timeline3/latest/embed/index.html?source=1lR3QCd_0yhMBltHHeiJsiJVcNuMMadP1fk2l-X4ZfDg&font=Default&lang=en&initial_zoom=2&height=800

Reference: De Schepper, S., Schreck, M., Beck, K.M., Matthiessen, J., Fahl, K. & Mangerud. G.
Early Pliocene onset of modern Nordic Seas circulation related to ocean gateway changes.
Nature Communications 6:8659, 10.1038/ncomms9659

Media Contact

Stijn De Schepper
Stijn.Deschepper@uni.no
47-555-83826

 @UiB

http://www.uib.no/ 

Stijn De Schepper | EurekAlert!

More articles from Earth Sciences:

nachricht Massive impact crater from a kilometer-wide iron meteorite discovered in Greenland
15.11.2018 | Faculty of Science - University of Copenhagen

nachricht The unintended consequences of dams and reservoirs
14.11.2018 | Uppsala University

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: UNH scientists help provide first-ever views of elusive energy explosion

Researchers at the University of New Hampshire have captured a difficult-to-view singular event involving "magnetic reconnection"--the process by which sparse particles and energy around Earth collide producing a quick but mighty explosion--in the Earth's magnetotail, the magnetic environment that trails behind the planet.

Magnetic reconnection has remained a bit of a mystery to scientists. They know it exists and have documented the effects that the energy explosions can...

Im Focus: A Chip with Blood Vessels

Biochips have been developed at TU Wien (Vienna), on which tissue can be produced and examined. This allows supplying the tissue with different substances in a very controlled way.

Cultivating human cells in the Petri dish is not a big challenge today. Producing artificial tissue, however, permeated by fine blood vessels, is a much more...

Im Focus: A Leap Into Quantum Technology

Faster and secure data communication: This is the goal of a new joint project involving physicists from the University of Würzburg. The German Federal Ministry of Education and Research funds the project with 14.8 million euro.

In our digital world data security and secure communication are becoming more and more important. Quantum communication is a promising approach to achieve...

Im Focus: Research icebreaker Polarstern begins the Antarctic season

What does it look like below the ice shelf of the calved massive iceberg A68?

On Saturday, 10 November 2018, the research icebreaker Polarstern will leave its homeport of Bremerhaven, bound for Cape Town, South Africa.

Im Focus: Penn engineers develop ultrathin, ultralight 'nanocardboard'

When choosing materials to make something, trade-offs need to be made between a host of properties, such as thickness, stiffness and weight. Depending on the application in question, finding just the right balance is the difference between success and failure

Now, a team of Penn Engineers has demonstrated a new material they call "nanocardboard," an ultrathin equivalent of corrugated paper cardboard. A square...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

“3rd Conference on Laser Polishing – LaP 2018” Attracts International Experts and Users

09.11.2018 | Event News

On the brain’s ability to find the right direction

06.11.2018 | Event News

European Space Talks: Weltraumschrott – eine Gefahr für die Gesellschaft?

23.10.2018 | Event News

 
Latest News

Purdue cancer identity technology makes it easier to find a tumor's 'address'

16.11.2018 | Health and Medicine

Good preparation is half the digestion

16.11.2018 | Life Sciences

Microscope measures muscle weakness

16.11.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>