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 compounds such as nitrate, NO3. Only then can it be used to build amino acids and proteins essential to all life.
Eventually the fixed nitrogen is returned to its gaseous state, a process called denitrification. Scientists have known for several decades that denitrification occurs in the deep, low-oxygen waters of the Pacific and Indian oceans.
If the Atlantic was the site of a lot of nitrogen fixation, that would have put the two processes half a world away from each other. Scientists had estimated that, at those distances, it could take 1,000 years to re-balance the ocean's nitrogen cycle if large-scale changes were to occur in either nitrogen fixation or denitrification – if climate change altered ocean temperatures and the rates of the two processes, for instance.
The new findings show the processes are happening within a few hundred miles of each other so the balance could be reached within a decade, the authors estimate. Deutsch compares the old assumption to a house where the thermostat is many rooms away from a window that has swung open, letting in cold air. The house could get quite chilly before the draft reaches the thermostat and the furnace turns on. But if the thermostat is in the same room as the window, the furnace will turn on and even out the temperature much faster.
In his research Deutsch used a novel analysis of surface nutrients in the world's oceans that relied on several decades of existing large-scale data on nitrogen-to-phosphorous ratios, phosphorous also playing a major role in primary production. His work has been supported by a NASA Earth System Science Fellowship and the UW Program on Climate Change.
"There has been a great deal of controversy in the literature as to whether fixed nitrogen in the ocean remains constant with time or fluctuates widely," says Jorge Sarmiento, professor of geosciences at Princeton University and one of the co-authors. "This study is a major advance for those of us who have been arguing that it is relatively stable."
Sandra Hines | EurekAlert!
The Great Unknown: Risk-Taking Behavior in Adolescents
19.01.2017 | Max-Planck-Institut für Bildungsforschung
A sudden drop in outdoor temperature increases the risk of respiratory infections
11.01.2017 | University of Gothenburg
An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...
Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...
Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.
While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...
Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales
Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...
Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.
As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...
19.01.2017 | Event News
10.01.2017 | Event News
09.01.2017 | Event News
20.01.2017 | Awards Funding
20.01.2017 | Materials Sciences
20.01.2017 | Life Sciences