Global warming is reducing ocean life, increasing atmospheric carbon dioxide, say scientistsDecember 07, 2006(Santa Barbara, Calif.) -- Alarming new satellite data show that the warming of the world's oceans is reducing ocean life while contributing to increased global warming. The ocean's food chain is based upon the growth of billions upon billions of microscopic plants. New satellite data show that ocean warming is reducing these plants -- thus imperiling ocean fisheries and marine life, according to an article in the Nov. 7 issue of the scientific journal Nature. "We show on a global scale that the growth of these plants, called phytoplankton, is strongly tied to changes in the warming of the ocean," said David Siegel, co-author and professor of marine science in the Department of Geography at the University of California, Santa Barbara. Siegel is also director of the Institute for Computational Earth System Science (ICESS). "Phytoplankton grow faster in a cool ocean and slower in a warm one," said Siegel. "The scary part is that the oceans are warming now -- probably caused by our emissions of greenhouse gases like carbon dioxide." These microscopic plants are predicted to grow even slower in the warmer oceans of the future. This in turn will reduce the food available to fish and other organisms, including marine birds and mammals, which are supported by the ocean's food chain. Phytoplankton are responsible for about the same amount of photosynthesis each year as all the plants on land combined. Another disturbing result of reduced phytoplankton is that our atmosphere depends on the consumption of atmospheric carbon dioxide by these plants. Reduced phytoplankton means less carbon dioxide is taken up by the ocean, which could speed global warming, contributing to a vicious cycle of increased warming. "Rising levels of carbon dioxide in the atmosphere play a big part in global warming," said lead author Michael Behrenfeld of Oregon State University. "This study shows that as the climate warms, phytoplankton growth rates go down and along with them the amount of carbon dioxide these ocean plants consume. That allows carbon dioxide to accumulate more rapidly in the atmosphere, which would produce more warming." The findings are from a NASA-funded analysis of data from the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) instrument on the OrbView-2 spacecraft, launched in 1997. The uninterrupted nine-year record shows in great detail the ups and downs of marine biological activity or productivity from month to month and year to year. Captured at the start of this data record was a major, rapid rebound in ocean biological activity after a major El Niño event. El Niño and La Niña are major warming or cooling events, respectively, that occur approximately every three to seven years in the eastern Pacific Ocean and are known to change weather patterns around the world. Scientists made their discovery by comparing the SeaWiFS record of the rise and fall of global ocean plant life to different measures of recent global climate change. The climate records included several factors that directly affect ocean conditions, such as changes in sea surface temperature and surface winds. The results support computer model predictions of what could happen to the world's oceans as the result of prolonged future climate warming. "When we compared changes in phytoplankton activity with simultaneous changes in climate conditions, the agreement between the two records was simply astonishing," Behrenfeld said. Ocean plant growth increased from 1997 to 1999 as the climate cooled during one of the strongest El Niño to La Niña transitions on record. Since 1999, the climate has been in a period of warming that has seen the health of ocean plants diminish. The new study also explains why a change in climate produces this effect on ocean plant life. When the climate warms, the temperature of the upper ocean also increases, making it "lighter" than the denser cold water beneath it. This results in a layering or "stratification" of ocean waters that creates an effective barrier between the surface layer and the nutrients below, cutting off phytoplankton's food supply. The scientists confirmed this effect by comparing records of ocean surface water density with the SeaWiFS biological data. University of California - Santa Barbara |
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| Related Global Warming Current Events and Global Warming News Articles Is global warming unstoppable? In a provocative new study, a University of Utah scientist argues that rising carbon dioxide emissions - the major cause of global warming - cannot be stabilized unless the world's economy collapses or society builds the equivalent of one new nuclear power plant each day. Oceans' uptake of manmade carbon may be slowing The oceans play a key role in regulating climate, absorbing more than a quarter of the carbon dioxide that humans put into the air. Research challenges for understanding landscape changes identified Nine research challenges and four research initiatives that are poised to advance the study of how Earth's landscapes change were unveiled today in a new report by the National Research Council. Study: Sea stars bulk up to beat the heat A new study finds that a species of sea star stays cool using a strategy never before seen in the animal kingdom. The sea stars soak up cold sea water into their bodies during high tide as buffer against potentially damaging temperatures brought about by direct sunlight at low tide. Drug industry, nonprofits join forces to fight world's neglected diseases Drug companies and nonprofit organizations are joining forces to develop new drugs and vaccines to target so-called "neglected" diseases that claim millions of lives in the developing world each year. Health care accounts for 8 percent of US carbon footprint The American health care sector accounts for nearly a tenth of the country's carbon dioxide emissions, according to a first-of-its-kind calculation of health care's carbon footprint. Cave Study Links Climate Change to California Droughts California experienced centuries-long droughts in the past 20,000 years that coincided with the thawing of ice caps in the Arctic. Reducing greenhouse gases may not be enough to slow climate change Because land use changes are responsible for 50 percent of warming in the US, policymakers need to address the influence of global deforestation and urbanization on climate change, in addition to greenhouse gas emissions. Past climate of the northern Antarctic Peninsular informs global warming debate The seriousness of current global warming is underlined by a reconstruction of climate at Maxwell Bay in the South Shetland Islands of the Antarctic Peninsula over approximately the last 14,000 years, which appears to show that the current warming and widespread loss of glacial ice are unprecedented. Climate variability impacts the deep sea Deep-sea ecosystems occupying 60% of the Earth's surface could be vulnerable to the effects of global warming warn scientists writing in the Proceedings of the National Academy of Sciences. More Global Warming Current Events and Global Warming News Articles |
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