عنوان

Banded corals:

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Banded corals:

[Article]

Druffel, ER

Changes in oceanic 14C levels during the Little Ice Age

Radiocarbon analyses and stable isotope measurements are presentedfor two recent cores of banded corals from the Florida Straits. These values provide arecord of variations in the ratio of carbon-14 to carbon-12 in the dissolved inorganiccarbon in the surface waters of the Gulf Stream from A.O. 1642 to 1800. An increasein the carbon-14/carbon-12 ratio of 7 per mil for coral growth during the early 1700'swas most likely induced by an increase in the carbon-14/carbon-12 ratio of 20 per milin the atmospheric carbon dioxide that occurred at about 1700. The ratios of oxygen-18 to oxygen-16 in these coral bands show a small decrease of water temperature(- 1°C) during the latter part of the Little Ice Age (1700 to 1725). These resultssupport the hypothesis that the increase in atmospheric carbon-14 at about 1700, andpossibly the temperature change as well, was caused by a decrease in solar activity(Maunder sunspot minimum).

1982

UC Irvine

[Article]

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