Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

50-million-year-old clam shells provide indications of future of El Niño phenomenon

14.09.2011
Earth warming will presumably not lead to a permanent El Niño state in the South Pacific Ocean.

This is the conclusion drawn by an international team of researchers after it investigated 50-million-year-old clam shells and wood from the Antarctic. The growth rings of these fossils indicate that there was also a climate rhythm over the South Pacific during the last prolonged interglacial phase of the Earth’s history resembling the present-day interplay of El Niño and La Niña.

Floods in Peru, drought in Australia: When the South Pacific Ocean warms up at an above-average rate every three to six years and “El Niño” influences weather patterns, the world in the coastal countries affected is turned completely around. Fishermen come back with empty nets, crops are lost, food prices increase and nearly everyone hopes the warm phase of the climate phenomenon “El Niño Southern Oscillation (ENSO)” will abate as quickly as possible.

The ENSO phenomenon still changes regularly from its cold phase (La Niña) to the warm phase (El Niño) and back. But what will things be like in the future? How will the worldwide temperature rise influence ENSO? Will there perhaps be a permanent El Niño? To answer this important question, scientists are looking at the past – particularly at the Eocene period 60 to 37 million years ago. “The Eocene is considered to be the last real prolonged warm period. At that time the Antarctic was ice-free and green. Even trees grew and we know about the water temperature of the ocean that it fluctuated between 10 and 16 degrees Celsius over the year,” says Thomas Brey, biologist at the Alfred Wegener Institute for Polar and Marine Research in the Helmholtz Association.

He and colleagues from the USA and Germany have now succeeded for the first time in verifying a rhythm according to the pattern of the ENSO phenomenon in the growth patterns of fossil clams and wood from the early Eocene. Their results will soon appear in the journal Geophysical Research Letter and are already available on its website in a text entitled “El Niño in the Eocene greenhouse recorded by fossil bivalves and wood from Antarctica”.

Brey and his colleagues investigated shells of the bivalve species Cucullaea Raea and Eurhomalea antarctica that are 50 million years old as well as a piece of wood from Seymour Island in the Antarctic. “Like trees, clams form growth rings. We measured their width and examined them for growth rhythms,” states Brey.

Whether clams grow depends on the availability of food and heat. “That means the change from “good” and “poor” environmental conditions at that time is still reflected in the width of the growth rings we find today. And as we were able to show, this change took place in the same three to six year rhythm we are familiar with in connection with ENSO today,” says Brey.

The shells are a real piece of luck for him. “To verify ENSO, we need climate archives that cover the largest possible period year by year. Back then clams lived for up to 100 years. This is a good basis for our work.”

To examine the significance of the growth rings of clams and wood, the researchers compared their measurement results with current ENSO data as well as with the ENSO-like fluctuations produced by a climate model of the Eocene. The result: all patterns correspond. “Our results are a strong indication that an ENSO phenomenon which fluctuated between warm and cold phases also existed in the warm Eocene,” says Brey.

Good news! Should the scientists be right, these findings mean for the future that in all likelihood the worldwide temperature rise will not disrupt the ENSO climate rhythm above the South Pacific Ocean.

The Alfred Wegener Institute 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 seventeen research centres of the Helmholtz Association, the largest scientific organisation in Germany.

Sina Löschke | idw
Further information:
http://www.awi.de

More articles from Earth Sciences:

nachricht Sea ice extent sinks to record lows at both poles
23.03.2017 | NASA/Goddard Space Flight Center

nachricht Less radiation in inner Van Allen belt than previously believed
21.03.2017 | DOE/Los Alamos National Laboratory

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

Im Focus: Researchers Imitate Molecular Crowding in Cells

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

When Air is in Short Supply - Shedding light on plant stress reactions when oxygen runs short

23.03.2017 | Life Sciences

Researchers use light to remotely control curvature of plastics

23.03.2017 | Power and Electrical Engineering

Sea ice extent sinks to record lows at both poles

23.03.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>