What's that smell?
Sauropod dinosaurs could have produced enough of the greenhouse gas methane to warm the climate many millions of years ago, at a time when the Earth was warm and wet. That's according to calculations reported in the May 8th issue of Current Biology, a Cell Press publication.
The hulking sauropods, distinctive for their enormous size and unusually long necks, were widespread about 150 million years ago. As in cows, methane-producing microbes aided the sauropods' digestion by fermenting their plant food.
dinosaurs could have produced more methane than all modern sources—both natural and man-made—put together
"Our calculations suggest that these dinosaurs could have produced more methane than all modern sources—both natural and man-made—put together."
Animal physiologists have studied methane production from a range of modern animals to derive equations that predict methane production from animals of different sizes. It turns out that those calculations depend only on the total mass of the animals in question. A medium-sized sauropod weighed something like 20,000 kilograms, and sauropods lived in densities ranging from a few large adults to a few tens of individuals per square kilometer.
"Clearly, trying to estimate this for animals that are unlike anything living has to be a bit of an educated guess," researcher Dave Wilkinson (of Liverpool John Moores University) said.
Global methane emissions from sauropods is calculated to have been 520 million tons (520 Tg) per year, comparable to total modern methane emissions. Before industry took off on modern Earth about 150 years ago, methane emissions were roughly 200 Tg per year. By comparison, modern ruminant animals, including cows, goats, giraffes, and others, produce methane emission of 50 to 100 Tg per year.
The study's conclusions not only show "just how strange and wonderful the workings of the planet are" but also serve as a useful reminder for the importance of microbes and methane for global climate, the researchers say.
Source: Cell Press
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