Antarctic marine communities resemble the primeval waters of millions years ago because modern predators - crabs and fish - are missing.
But this is about to change. 'The crabs are on the doorstep. They are sitting in deep water only a couple of hundred bathymetric metres away from the slightly cooler shallow water in the Antarctic shelf environment,' says Dr Sven Thatje of the National Oceanography Centre, Southampton (NOCS).
Predators like the shell-cracking crabs that dominate bottom communities in temperate and tropical waters have been shut out of Antarctica because it is too cold for them.
'Crabs have a problem in cold water,' says Dr Thatje, a biologist at the University of Southampton's School of Ocean and Earth Science, based at NOCS, 'They cannot flush magnesium out of their blood. So when they are already moving slowly because of the cold, the magnesium acts as a narcotic causing them to pass out and die.' Released from the dangers of predation, filter feeders such as brittlestars thrive in dense populations. Giant sea spiders and marine woodlice share the ocean bottom with fish that have antifreeze proteins in their blood.
Dr Thatje is discussing his findings at a science meeting of the American Association for the Advancement of Science (AAAS) in Boston today Under Thin Ice: Global Warming and Predatory Invasion of the Antarctic Seas (19.00 hours GMT 15th February 2008) with colleagues, Rich Aronson of the Dauphin Island Sea Lab in Alabama and Cheryl Wilga of the University of Rhode Island. Along with scientists from the British Antarctic Survey, BAS, the team studied the benthic communities living in different habitats around Antarctica.
'Antarctic marine communities are functionally Paleozoic - typical of around 250 million years ago,' says paleobiologist Rich Aronson. 'If the crabs' invasion succeeds, they will devastate Antarctica's spectacular Paleozoic-type fauna and fundamentally alter its ecological relationships.'
In January 2007 Dr Sven Thatje and a group of ocean biologists from NOCS and BAS discovered crabs massing in deeper slightly warmer waters, ready to move into the Antarctic shallows should they warm up sufficiently.
Understanding the changes of the past may help scientists to determine how a rise in temperatures may further transform this continent. In a report to be published in Ecology Life Hung By A Thread: Endurance of Antarctic Fauna In Glacial Periods, Sven Thatje reveals that harsh conditions during the Ice Ages pushed Antarctic life to the limit. With ice coverage ten times thicker than today's, the extreme climate conditions in Antarctica during past Ice Ages were so severe that animals were forced into migration to avoid extinction.
He and colleagues from BAS, and the Alfred Wegner Institute, Germany found that larger animals such as penguins, whales and seals were dependent upon areas of open water in the ice known as polynyas. These polynyas acted as vital oases providing access to food such as krill.
Dr Thatje said: 'The existence of open water was essential for the survival of marine plants - the base of the food web. Reduced to such refuges much of today's life in the high Antarctic would have hung by a thread. Limited resources restricted the abundance and productivity of both terrestrial and marine life.'
Dispersal of Fish Eggs by Water Birds – Just a Myth?
19.02.2018 | Universität Basel
Removing fossil fuel subsidies will not reduce CO2 emissions as much as hoped
08.02.2018 | International Institute for Applied Systems Analysis (IIASA)
Study published in the journal ACS Applied Materials & Interfaces is the outcome of an international effort that included teams from Dresden and Berlin in Germany, and the US.
Scientists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) together with colleagues from the Helmholtz-Zentrum Berlin (HZB) and the University of Virginia...
Novel highly efficient and brilliant gamma-ray source: Based on model calculations, physicists of the Max PIanck Institute for Nuclear Physics in Heidelberg propose a novel method for an efficient high-brilliance gamma-ray source. A giant collimated gamma-ray pulse is generated from the interaction of a dense ultra-relativistic electron beam with a thin solid conductor. Energetic gamma-rays are copiously produced as the electron beam splits into filaments while propagating across the conductor. The resulting gamma-ray energy and flux enable novel experiments in nuclear and fundamental physics.
The typical wavelength of light interacting with an object of the microcosm scales with the size of this object. For atoms, this ranges from visible light to...
Stable joint cartilage can be produced from adult stem cells originating from bone marrow. This is made possible by inducing specific molecular processes occurring during embryonic cartilage formation, as researchers from the University and University Hospital of Basel report in the scientific journal PNAS.
Certain mesenchymal stem/stromal cells from the bone marrow of adults are considered extremely promising for skeletal tissue regeneration. These adult stem...
In the fight against cancer, scientists are developing new drugs to hit tumor cells at so far unused weak points. Such a “sore spot” is the protein complex...
In an article that appears in the journal “Review of Modern Physics”, researchers at the Laboratory for Attosecond Physics (LAP) assess the current state of the field of ultrafast physics and consider its implications for future technologies.
Physicists can now control light in both time and space with hitherto unimagined precision. This is particularly true for the ability to generate ultrashort...
13.04.2018 | Event News
12.04.2018 | Event News
09.04.2018 | Event News
19.04.2018 | Materials Sciences
19.04.2018 | Physics and Astronomy
19.04.2018 | Physics and Astronomy