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
By saving cost and energy, the lighting revolution may increase light pollution
23.11.2017 | Helmholtz-Zentrum Potsdam - Deutsches GeoForschungsZentrum GFZ
Frictional Heat Powers Hydrothermal Activity on Enceladus
23.11.2017 | Universität Heidelberg
Heat from the friction of rocks caused by tidal forces could be the “engine” for the hydrothermal activity on Saturn's moon Enceladus. This presupposes that...
The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.
Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....
The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.
Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...
Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.
That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...
Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.
During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....
15.11.2017 | Event News
15.11.2017 | Event News
30.10.2017 | Event News
23.11.2017 | Information Technology
23.11.2017 | Physics and Astronomy
23.11.2017 | Life Sciences