[BBC NEWS] Warming risks Antarctic sea life - 그대로 퍼옴.
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By Helen Briggs
Science reporter, BBC News, Boston |
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Surprise find: A king crab in the Antarctic deep
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Robo-sub grabs crab
Crabs are poised to return to the Antarctic shallows, threatening creatures such as giant sea spiders and floppy ribbon worms, says a UK-US team.
Some have evolved without predators for tens of millions of years.
Bony fish and sharks would move in if waters warm further, threatening species with extinction, they say.
In the last 50 years, sea surface temperatures around Antarctica have risen by 1 to 2C, which is more than twice the global average.
Loss of species
Speaking in Boston at the annual meeting of the American Association for the Advancement of Science (AAAS), the researchers said global warming could fundamentally change the ecosystem, leading to the loss of some species.
"Sharks are going to arrive in Antarctica as long as the warming trend
continues, a bit more slowly than crabs - crabs are going to get there
first," said Professor Cheryl Wilga of the University of Rhode Island
(URI), US. "But once they do get there they are capable of eating the
organisms that live there."
The water only needs to remain above freezing year round for it to
become habitable to some sharks, and at the rate we're going, that
could happen this century
Professor Wilga said the arrival of sharks and shell-crushing bony fishes would lead to dramatic changes in the number and proportions of species found there.
Shrimp, ribbon worms and brittle stars are likely to be the most vulnerable to population declines.
Dr Sven Thatje of the National Oceanography Centre at the University of Southampton, UK, said animals living in shallow water in Antarctica were unique on Earth today because they evolved in a very cold environment over tens of millions of years.
Extreme conditions
"In the course of a process we call Antarctic cooling that started about 40 million years ago, all major seafloor predators such as sharks and crabs went extinct in Antarctica because they were not able to cope with these extreme conditions," he told BBC News.
"Today, global warming is removing barriers to invasions and we've seen
recently that crabs, especially king crabs, are on the doorstep of
Antarctica - they can potentially re-invade the shallow waters if
warming continues."
The researchers say urgent local and global actions are needed to protect this last pristine environment.
"We have to act now in Antarctica as elsewhere to save the diversity of the planet," said Dr Richard Aronson of Dauphin Island Sea Laboratory in Alabama.
He said measures were needed to stop alien species being brought in through ships' ballast water.
"The local actions are to control ship traffic and control dumping of ballast waters," he told the BBC. "The global actions are what we've been saying for all other environments - we have to control emissions of greenhouse gases."
Strange creatures
Animals that live on the seafloor of Antarctica are some of the strangest creatures on Earth.
The extreme cold and lingering darkness has presented huge challenges to marine life over the passage of time, leading to the evolution of fish equipped with anti-freeze proteins in their blood, and a proliferation of filter feeders on the seabed.
Fast-moving shell-crushing animals such as crabs and ocean-going sharks that are normally key predators have long been kept at bay, as their bodies cannot cope with very cold conditions.
This has led to a dominance on the Antarctic seafloor of soft-bodied, slow-moving invertebrates, similar to those found in ancient oceans prior to the evolution of shell-crushing predators.
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출처: http://news.bbc.co.uk/2/hi/science/nature/7248025.stm
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몇 주 전에 엘고어의 불편한 진실을 구입하였다. 사진과 그림으로 연결된 하나의 리포트에는 내가 몰랐던 사실들이 뭉치째로 들어 있었다. 아직 다 읽지는 못하였지만.-.- 평소 머릿 속에 뜬구름 식으로 자리 잡고 있던 지구 온난화에 대한 생각을 구체적으로, 그리고 우리가 해야할 실천방안에 대해서 나와 있었다. 하지만 무슨 일이든 행동으로 나타내지 않으면 아무 소용이 없는 것을.
반성하고 반성하지만 그것으로는 턱없이 부족한 것을. 스스로 실천하고, 주변사람들과도 나눠야 하는데.
그게 참 쉽지가 않더라. 뭐, 아무튼 지구 온난화로 남극에 있던 동물들이 다른 곳에 있던 포식자의 이동으로 멸종된다면 그만큼 가슴 아픈 일도 없을 거 같다. 나름 진화과정에서 포식자를 피하는 방법으로 추위 적응을 택하고 열심히 살아갈 텐데 말이다.
