At the end of the last Ice Age, atmospheric carbon dioxide levels rose rapidly as the planet warmed; scientists have long hypothesized that the source was CO2 released from the deep ocean.
But a new study using detailed radiocarbon dating of foraminifera found in a sediment core from the Gorda Ridge off Oregon reveals that the Northeast Pacific was not an important reservoir of carbon during glacial times. The finding may send scientists back to the proverbial drawing board looking for other potential sources of CO2 during glacial periods.
The study, which was supported by the National Science Foundation and the University of Michigan, was published online this week in Nature Geoscience.
"Frankly, we're kind of baffled by the whole thing," said Alan Mix, a professor of oceanography at Oregon State University and an author on the study. "The deep North Pacific was such an obvious source for the carbon, but it just doesn't match up. At least we've shown where the carbon wasn't; now we just have to find out where it was."....
....."These are volcanically active regions, so the input of carbon from volcanoes, which lacks radiocarbon because of its great age, needs to be looked at," Lund pointed out. "But it is premature to draw any conclusions."
The researchers' next step will be to look for chemical traces of volcanic influence...
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