2010年2月5日金曜日

Oceans reveal further impacts of climate change, says UAB expert

【出展引用リンク】: http://www.eurekalert.org/pub_releases/2010-02/uoaa-orf020410.php

【引用以下の通り】

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Public release date: 4-Feb-2010
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Contact: Andrew Hayenga
ahayenga@uab.edu
205-934-1676
University of Alabama at Birmingham 

Oceans reveal further impacts of climate change, says UAB expert





 VIDEO: UAB biologist Jim McClintock, Ph.D., discusses the impact of ocean acidification.



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BIRMINGHAM, Ala. – The increasing acidity of the world's oceans – and that acidity's growing threat to marine species – are definitive proof that the atmospheric carbon dioxide that is causing climate change is also negatively affecting the marine environment, says world-renowned Antarctic marine biologist Jim McClintock, Ph.D., professor in the University of Alabama at Birmingham (UAB) Department of Biology.
"The oceans are a sink for the carbon dioxide that is released into the atmosphere," says McClintock, who has spent more than two decades researching the marine species off the coast of Antarctica. Carbon dioxide is absorbed by oceans, and through a chemical process hydrogen ions are released to make seawater more acidic.
"Existing data points to consistently increasing oceanic acidity, and that is a direct result of increasing carbon dioxide levels in the atmosphere; it is incontrovertible," McClintock says. "The ramifications for many of the organisms that call the water home are profound."




 IMAGE: Jim McClintock, Ph.D., is a leading polar marine biologist who is researching the impacts of ocean acidification.



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A substance's level of acidity is measured by its pH value; the lower the pH value, the more acidic is the substance. McClintock says data collected since the pre-industrial age indicates the mean surface pH of the oceans has declined from 8.2 to 8.1 units with another 0.4 unit decline possible by century's end. A single whole pH unit drop would make ocean waters 10 times more acidic, which could rob many marine organisms of their ability to produce protective shells – and tip the balance of marine food chains.
"There is no existing data that I am aware of that can be used to debate the trend of increasing ocean acidification," he says.
McClintock and three co-authors collected and reviewed the most recent data on ocean acidification at high latitudes for an article in the December 2009 issue of Oceanography magazine, a special issue that focuses on ocean acidification worldwide. McClintock also recently published research that revealed barnacles grown under acidified seawater conditions produce weaker adult shells.



Antarctica as the Ground Zero for Climate Change

McClintock says the delicate balance of life in the waters that surround the frozen continent of Antarctica is especially susceptible to the effects of acidification. The impact on the marine life in that region will serve as a bellwether for global climate-change effects, he says.
"The Southern Ocean is a major global sink for carbon dioxide. Moreover, there are a number of unique factors that threaten to reduce the availability of abundant minerals dissolved in polar seawater that are used by marine invertebrates to make their protective shells," McClintock says.
"In addition, the increased acidity of the seawater itself can literally begin to eat away at the outer surfaces of shells of existing clams, snails and other calcified organisms, which could cause species to die outright or become vulnerable to new predators."
One study McClintock recently conducted with a team of UAB researchers revealed that the shells of post-mortem Antarctic marine invertebrates evidenced erosion and significant loss of mass within only five weeks under simulated acidic conditions.
McClintock says acidification also could exert a toll on the world's fisheries, including mollusks and crustaceans. He adds that the potential loss of such marine populations could greatly alter the oceans' long-standing food chains and produce negative ripple effects on human industries or food supplies over time.
"So many fundamental biological processes can be influenced by ocean acidification, and the change in the oceans' makeup in regions such as Antarctica are projected to occur over a time period measured in decades," McClintock says.
"Evolution simply may be unable to keep up, because it typically takes marine organisms longer periods, hundreds or even thousands of years to naturally adapt," he says. "But ocean acidification is simply happening too quickly for many species to survive unless we reverse the trend of increasing anthropogenically generated carbon dioxide that is in large part driving climate change."
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About UAB's Jim McClintock, Ph.D.

An expert on Antarctica who has logged more than two dozen trips to the continent, McClintock's ongoing research explores the chemical defenses of polar marine organisms and impacts of ocean acidification on marine invertebrates. McClintock Point, located at the entrance of a three-mile stretch of land known as Explorers Cove in Antarctica, was named for the biologist in 1998.
Follow McClintock, fellow UAB research biologist Charles Amsler, Ph.D., and their research team's upcoming visit to Antarctica from February through May at www.antarctica.uab.edu. Later in 2010 McClintock will lead his third Climate Challenge Education Mission cruise to Antarctica.



About the UAB Department of Biology

The UAB Department of Biology is a dynamic academic partnership that provides a broad-based graduate and undergraduate curriculum. Most members of the graduate faculty have research specialties in comparative biochemistry, physiology and eco-physiology of aquatic organisms. A second, important department research focus is environmental microbiology.
EDITOR'S NOTE: The University of Alabama at Birmingham (UAB) is a separate, independent institution from the University of Alabama, which is located in Tuscaloosa. Please use University of Alabama at Birmingham on first reference and UAB on all consecutive references.


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【私のコメント】:


海洋の酸性化が、世界的に進展している。


その原因はと考えられることは、近代の経済活動における、工業活動の煤煙による降雨の雨水の酸性化や未処理の酸性の排水の増大や陸上の農業用肥料による窒素肥料の河川への流出によるものが考えられる。


 人類の活動の最終的な影響の行きつく果てや行きつく場所が、海洋の空間なのである。


人類の活動に伴う影響・結果により、酸性化が進展され、海洋沿岸周辺に大きく拡散・拡大されて集積されてきている。


 海洋は、この酸性化だけでなく、他の農薬や科学汚染物質等の人類の活動の影響を受けている。


海洋は、国境を越えて、種種の人間社会の陸上活動の影響を受けている。


その影響は、人口の世界的な増大とともに、年々大きなものになってきている。


それとともに、海洋生物等の生息環境が影響されてきている。


このようなことが、進展されていることを人々は、十分に認識していくことが重要である。


 海洋の汚染や酸性化を防ぐとともに、海洋観測研究をもっと充実・拡大。発展させていくことが時代的な要請がやって来ている。


環境に対する時代的な認識が重要で、必須条件であり、必要なことなのである。


人類社会の安寧な未来を築くために、環境負荷の多い産業や生活の仕様から、速やかに環境負荷に少ないものに、変えていかなければならない。


 世界的な持続可能な人間活動に関わる環境の創生が、政治的、行政・政策的に急がれるのである。

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