A friend of mine (well, maybe it was me) used to be fond of the expression "lower than whale shit." The idea, of course, was that, since whale feces had to sink to the bottom of the deep ocean it, you just couldn't get much lower than that. Turns out that would be, well, wrong.
Truth is, whale poop doesn't necessarily sink. In fact, a significant component of it floats at the surface of the ocean and has a real impact on the productivity of fisheries. Joe Roman (University of Vermont) and James McCarthy (Harvard), publishing October 11 in PLoS One, have determined that deep-feeding whales actually carry nutrients back to the surface in a an "upward biological pump", rather than sending nutrients on a one-way trek to the abyss. They estimate the the nutrient input of whale excrement to the Gulf of Maine is greater than that of all rivers combined. Roman and McCarthy go on to suggest that, historically, whales likely played a very significant role in providing a nutrient base for fisheries and that the decline in whale abundance may be one of many factors that have led to declining productivity.
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