Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Seafloor creatures destroyed by ice action during ice ages

18.10.2005


The ice ages made massive changes to the Earth’s landscape. But what was happening below the ice in the oceans?

Research by marine scientists reveals that it was a time of mass destruction as whole communities of animals were wiped out by ice sheets scouring the sea floor.

In the past it has been thought that these ecosystems somehow dodged extinction by recolonising from nearby habitats that escaped obliteration. But researchers at the National Oceanography Centre, Southampton (NOC) and the British Antarctic Survey (BAS) reveal a bleaker scenario.



Dr Sven Thatje, an ecologist at NOC has been working with geoscientists, Dr Claus-Dieter Hillenbrand and Dr Rob Larter at BAS examining one of the harshest environments on Earth - the Antarctic seafloor.

Writing in the October issue of Trends in Ecology & Evolution the scientists provide new evidence that suggests that seafloor organisms were either erased by the advance of ice sheets across the Antarctic continental shelf or starved to death as links in the food chain were broken by the permanent ice cover. There would have been no refuge for shallower living animals further down the continental slope, as huge sediment slides would have buried them. Typically these ecosystems would have been made up of sponges, urchins, sea fan corals, and starfish.

Dr Thatje said: ’We show that during ice ages seafloor organisms emigrated to the deep sea - below the effects of the sediment slides and ice. From there, organisms may have invaded open marine shelters of the Antarctic shelf, which were not affected by the advance of ice masses. Or these animals may have recolonised the Antarctic shelf from the deep-sea during the warm period following each ice age.

’Either way it is an impressive feat against the odds as the extreme cold means that these animals respond much more slowly to the destruction of their habitat than elsewhere in the oceans. They have lower metabolic rates that lower their growth and reproductive rates. Elsewhere in the oceans, a brisingid starfish would reproduce annually and live for ten years. In the Antarctic these starfish can reach 100-years-old but reproduce only once every ten years. This means that full community recuperation takes up to hundreds of years.’

Dr Claus-Dieter Hillenbrand explained: ’Until now it was commonly thought that the destructive action of the ice sheets was not significant enough to eradicate all the fauna and that desolate patches were recolonised from surrounding areas. But our research confirms that the destruction was wholesale with very little surviving. Even today calving icebergs ploughing across the seafloor destroy everything in their path. Imagine the impact of ice sheets during the ice ages that covered a much wider area in a time of lower sea levels.’

The team’s research will lead to a radical rethink of the evolutionary history of Antarctica as the work challenges all the accepted theories. The scientists argue that shallow water animals were retreating to the deep ocean and then returning to recolonise Antartica’s shelf seas. Clues to how these two very different communities could have achieved this may lie in the animals’ DNA.

Sven Thatje continued: ’Our work means that the text books will need to be rewritten. Our next task is to reconstruct what happened in Antarctica during these periods of climate change and study the genetic and biological links between deep sea and shallow water communities.’

Kim Marshall-Brown | EurekAlert!
Further information:
http://www.soton.ac.uk

More articles from Ecology, The Environment and Conservation:

nachricht Successful calculation of human and natural influence on cloud formation
04.11.2016 | Goethe-Universität Frankfurt am Main

nachricht Invasive Insects Cost the World Billions Per Year
04.10.2016 | University of Adelaide

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

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

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

Im Focus: Molecules change shape when wet

Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water

In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...

Im Focus: Fraunhofer ISE Develops Highly Compact, High Frequency DC/DC Converter for Aviation

The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.

Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

UTSA study describes new minimally invasive device to treat cancer and other illnesses

02.12.2016 | Medical Engineering

Plasma-zapping process could yield trans fat-free soybean oil product

02.12.2016 | Agricultural and Forestry Science

What do Netflix, Google and planetary systems have in common?

02.12.2016 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>