Iron dust, the gold of the oceans and rarest nutrient for most marine life, can be washed down by rivers or blown out to sea or – a surprising new study finds – float up from the sea floor.
The discovery, published online Feb. 8 in Nature Geoscience, connects life at the surface to events occurring at extreme depths and pressures.
The two worlds were long assumed to have little interaction.
A team from the University of Southern California, Woods Hole Oceanographic Institution and Lawrence Berkeley National Laboratory took samples from the East Pacific Rise, a volcanic mid-ocean ridge.
The group found that organic compounds capture some iron spewed by hydrothermal vents, enabling it to be carried away in seawater.
Iron trapped in this way does not rust.
For the scientists, discovering shiny iron in the ocean was like fishing a dry sponge out of a bath.
“Everything we know about the chemical properties of iron tells us that it should be oxidized. It should be rusted,” said team leader Katrina Edwards of USC.
The metal’s purity has practical value. Aquatic organisms metabolize pure iron much more easily than its rusted form, Edwards said.
How much captured iron floats into surface waters remains unknown. But any that does would nourish ocean life more efficiently than the oxidized iron from regular sources.
“This is one potential mechanism of creating essentially a natural iron fertilization mechanism that’s completely unknown,” Edwards said.
Some marine scientists have called for iron fertilization because of the metal’s crucial place in the aquatic food chain. Iron is the limiting nutrient in most parts of the oceans, meaning that its scarcity is the only thing standing in the way of faster growth.
Iron’s equivalent on land is nitrogen. Crop yields rose dramatically during the 20th century in part because of increased nitrogen fertilization.
The expedition team discovered the phenomenon of iron capture serendipitously. Edwards and her collaborators were studying deep-sea bacteria that catalyze the iron rusting reaction.
Of the possible reactions that support microbial communities on rocks, iron oxidation is one of the most important, Edwards explained.
Unfortunately, she added, “it’s probably the least well understood major metabolic pathway in the microbial world.”
The bacteria involved do not grow well in culture, so the researchers are using a range of molecular techniques to search for genes related to iron oxidation.
One major question involves the importance of bacteria-catalyzed oxidation versus the conventional rusting process. How much of the world’s iron is deposited with bacterial help? And how much escapes both bacteria and the natural oxidation process?
The sea floor holds the answer.
The samples were collected continuously using a remote sampling device deployed and retrieved from the research vessel Atlantis between May 16 and June 27, 2006.
The other team members were Brandy Toner of Woods Hole, who was first author on the Nature Geoscience study; Steven Manganini, Cara Santelli, Olivier Rouxel and Christopher German, also of Woods Hole; James Moffett, professor of biological sciences at USC; and Matthew Marcus of the Advanced Light Source at Lawrence Berkeley National Laboratory.
The research was supported by the National Science Foundation, NASA and the Department of Energy.
Carl Marziali | Newswise Science News
GPM sees deadly tornadic storms moving through US Southeast
01.12.2016 | NASA/Goddard Space Flight Center
Cyclic change within magma reservoirs significantly affects the explosivity of volcanic eruptions
30.11.2016 | Johannes Gutenberg-Universität Mainz
A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.
Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...
The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.
The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...
Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water
In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...
The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.
Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
02.12.2016 | Medical Engineering
02.12.2016 | Agricultural and Forestry Science
02.12.2016 | Physics and Astronomy