10.06.: Pacific coral
Subtropical coral reveals abrupt early-twentieth-century freshening in the western North Pacific Ocean
According to a recently published paper in the magazine Geology: Sea surface temperature and salinity play key roles in ocean circulation and therefore are major factors in global climate. Instrumental observations are scarce, particularly on salinity, complicating the identification of twentieth century climate change. Now, a reconstruction based on the chemical composition of a 130-year old coral from the western North Pacific Ocean suggests a major shift in salinity that took place between 1905 and 1910.
Annually banded corals have previously been used to reconstruct climate in the tropics. However, at higher latitudes the application of this method is often impossible – stony corals do not survive prolonged exposure to cool temperatures. But the new coral material has been recovered off the Ogasawara Islands (Japan), where warm waters are provided by the northward-flowing Kuroshio Current. Observations from weather stations reveal a shift in the atmospheric circulation over Asia and the North Pacific at about the time of the salinity change, suggesting that the ocean responded to changing winds. The new information on the interaction of ocean and atmosphere will expand our knowledge on how climate works, and may also improve the predictability of future climate changes.
Felis, T, Suzuki, A, Kuhnert, H, Dima, M, Lohmann, G, Kawahata, H (2009)
Subtropical coral reveals abrupt early-twentieth-century freshening in the western North Pacific Ocean. Geology, 37(6): 527-530
Dr. Thomas Felis
phone: + 421 - 218-65071
MARUM - Public Relations
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Sampling of the coral close to Ogasawara-Islands.
The Japanese Ogasawara-Islands: The researchers on their way to the sampling location.
X-ray image of the coral core. The density bands show the period from 1900 to about 1928.