The Atlantic Ocean doesn't receive the mother lode of fixed nitrogen, the building block of life, after all. Instead, comparing fathom for fathom, the Pacific and Indian oceans experience twice the amount of nitrogen fixing as the Atlantic, say researchers in the Jan. 11 issue of Nature.
The title of an accompanying News and Views piece says it all, "Looking for N2 Fixation in all the Wrong Places."
It's important to have a global picture of where nitrogen fixation is occurring that is where nitrogen gas is being converted into substances like nitrate that are usable by life in order to understand the environmental controls on nitrogen fixation and its likely response to climate change in the past and in the future, says Curtis Deutsch, a University of Washington research assistant and lead author of a paper in the Jan. 11 issue of Nature. The new research, for example, indicates that the inventory of nitrogen in the oceans is likely to be less subject to major fluctuations than had been assumed.
Because it has been thought that nitrogen fixation is limited without enough iron, the conventional wisdom for the past decade dictated that the Atlantic Ocean would be the prime site for fixing nitrogen. That's because compared to the other low-latitude oceans, the Atlantic is peppered with iron-laden dust blowing off the African continent.
Winds can't carry such dust all the way across the Pacific Ocean because it is so vast. Iron may still be a limiting factor in nitrogen fixation, but if it is, then the Pacific and Indian oceans are getting iron from some source other than atmospheric dust, Deutsch says.
The new research also means places where nitrogen is being fixed by certain microorganisms are in close proximity to where it is being pulled back apart into its gaseous state by a different kind of micoorganism, he says.
Nitrogen gas, N2, is unusable by life. It has to be fixed, that is, latched onto other chemicals to form co
Contact: Sandra Hines
University of Washington