Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Fossils provide insight into origin of unique Antarctic ecosystem

19.04.2013
The circum-Antarctic Southern Ocean is an important region for global marine food webs and carbon cycling because of sea-ice formation and its unique plankton ecosystem.

The origin of its ecosystems can be traced back to the emergence of the Antarctic ice sheets approximately 33.6 million years ago. This discovery was made by an international team including scientists from the Goethe University and the Biodiversity and Climate Research Centre in Frankfurt, Germany.


A characteristic dinoflagellate cyst found in sediments dating back to the early Oligocene (33 million years ago). © Alexander Houben

Their study, published today in Science, shows that the development of the sea-ice ecosystem possibly triggered further adaptation and evolution of larger organisms such as baleen whales and penguins

The scientists analysed sediment samples from drill cores on the seafloor, which were obtained in 2010 off the coast of Antarctica, as part of the Integrated Ocean Drilling Program (IODP). The cores reach nearly 1000 meters beneath the seafloor and provide new insights into a long gone past. A study published in 2012 demonstrated that subtropical plants covered Antarctica about 53 million years ago. In the course of the following 20 million years, the global climate cooled continuously. The new study focuses on the interval 33.6 million years ago when within a short time an enormous ice sheet covered Antarctica. This changed the life conditions and the ecosystems on the Antarctic continent and the surrounding Southern Ocean dramatically.

Tiny witnesses: Dinoflagellates

The ocean plankton mainly consist of algae, most of which are not preserved in sediment samples from drill cores. In contrast, single-celled dinoflagellates, a group of algae containing organic fossilizable substance, do preserve in sedimentary sequences over millions of years. This makes them a valuable tool to reconstruct environmental.

The researchers found that when Antarctica was sub-tropical and ice-free, the surrounding seas were inhabited by a diverse array of dinoflagellates characteristic for relatively warm climates. However, from the moment that the ice cap formed, the diversity suddenly collapsed, and from that moment, only species occurred that are adapted to temporary sea-ice cover and characterize modern sea-ice environments around Antarctica. They are present in high numbers only when the sea ice melts in spring and summer, and therefore are available as a food source for higher organisms only during a short period of the year.

New species due to food shortage

The seas around Antarctica play a critical role in the food web of the ocean. Algal blooms only occur in summer, when the sea ice melts. These blooms are a key food source for both small single-cell organisms such as certain species of dinoflagellates and for larger organisms.

“The sudden turnover in the dinoflagellate assemblages indicates clearly that the entire plankton ecosystem of the Antarctic waters had changed”, explains Prof. Jörg Pross, co-author of the study and paleoclimatologist at the Goethe University and the Biodiversity and Climate Research Centre (BiK-F) in Frankfurt, Germany. “The explosion of dinoflagellates adapted to a temporary sea-ice cover testifies to an in-depth reorganization of the food web in the Southern Ocean.”

Larger animals higher up in the ocean’s food chain probably adapted their diet because the algal growth season became shorter and more intense. Jörg Pross sums up: „Our data suggest that this change may have promoted the evolution of modern baleen whales and penguins“.

These results stress that major climate change is often accompanied by particularly rapid biological evolution.

For further information please contact:

Prof. Dr. JörgPross
Paleoenvironmental Dynamics Group, Palentology Section, Institute of Geosciences,
Goethe University and
LOEWE Biodiversity and Climate Research Center
Phone +49 (0)69 798 40181 joerg.pross@em.uni-frankfurt.de

or

Dr. Julia Krohmer
LOEWE Biodiversity and Climate Research Center (BiK-F),
Transfer office
Tel. +49 (0)69 7542 1837
julia.krohmer@senckenberg.de

Paper:
A.J.P. Houben, P.K. Bijl, J. Pross et al: Reorganization of Southern Ocean Plankton Ecosystem at the Onset of Antarctic Glaciation, Science, DOI 10.1126/science.1223646

LOEWE Biodiversität und Klima Forschungszentrum, Frankfurt am Main
With the objective of analysis the complex interactions between biodiversity and climate through a wide range of methods, the Biodiversität und Klima Forschungszentrum [Biodiversity and Climate Research Centre] (BiK‐F) has been funded since 2008 within the context of the Landes‐Offensive zur Entwicklung Wissenschaftlich-ökonomischer Exzellenz (LOEWE) of the Land of Hessen. The Senckenberg Gesellschaft für Naturforschung and Goethe University in Frankfurt as well as other, directly involved partners, co‐operate closely with regional, national and international institutions in the fields of science, resource and environmental management, in order to develop projections for the future and scientific recommendations for sustainable action. For further details, please visit www.bik‐f.de

Sabine Wendler | Senckenberg
Further information:
http://www.senckenberg.de
http://www.bik‐f.de

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

A Map of the Cell’s Power Station

18.08.2017 | Life Sciences

Engineering team images tiny quasicrystals as they form

18.08.2017 | Physics and Astronomy

Researchers printed graphene-like materials with inkjet

18.08.2017 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>