A Zen discovery: Unrusted iron in ocean
February 8, 2009
Iron spewed from hydrothermal vents and carried away by seawater does not rust. Credit: Nicolle Rager-Fuller, National Science Foundation
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.
Source: University of Southern California
Feb 08, 2010
I had thought that iron sulphate breakdown by bacteria had been studied for decades. iron oxidation is of immense economic significance. If bacteria play an important part is is difficult to imagine how or why it has not been studied to date.
If you find such a comment either unfathomable, bizarre, or outside your ability to take seriously, then you are not ready for the subject.
When you are serious and real then it will be revealed to you, if you put yourself into it.
It is purposely pitched that way to keep those who do not yet posses the psychology to deal with it - out of it.
What it requires is a stable psychological condition. Dump the monkey-and you may then possibly reach the answers it has always inherently held.
In regard to iron fertilization, most opponents to iron fertilization aren't necessarily against iron itself, but are more against the iron composites being used. Most experiments want to use iron based sulfates and sulfides which lead to acidification reactions.
Maybe because the idea of fertilizing the oceans is ludicrous enough not to need naysayers? I don't think you really need to address the CO2 implications of this experiment, the staggering cost of fertilization.
Let's start with some fun math. Volume of the ocean = 1.35 X10^21 Liters of water. lets say a low level fertilization and aim for 10ppm. Or 10mg/L 1.35 X 10^15 Kilograms, For reference that's 1.35 quadrillion kilograms. Or 1,350 billion metric tons.
For those of you keeping track, if we divert the total of the Worlds iron production annually direct to the oceans, then we will have increased the iron content of the oceans by 10 parts per million by 3010AD give or take a couple decades, assuming we don%u2019t run out first.. This does not factor in settling and deposition, or the fact that 10ppm is not really enough to make a difference over the next millenia. If AGW is right the 1000 years might be a little bit long on the time scale don'tcha think?
And to the first tree stump to say we don't need 10ppm, ok, at 100ppb we're still talking about a 10 year project costing the value of the entire world production of iron plus the cost of processing and transportation. For the record 1,350 billion metric tons is going to run in the neighborhood of US$300 Trillion give or take several Trillion, it's hard to be accurate when the rounding error is geting as large as a small countries entire GNP.
Iron fertilization wouldn't be feasable on a large enough scale to be considered in a CO2 "solution" as Roach has pointed out.
Realistically iron fertilization is a means by which to revitalize depleted wildlife banks for the commercial fishing and other sea based food industries. Effectively arguing against it is similar to arguing against using fertilizer on corn fields. No one in their right mind would argue against it, but conversely, no one in their right mind would support this as a CO2 fix regardless of whether CO2 needs fixing or not. I doubt the scientists involved are really touting this as an AGW fix beyond it's ability to gain grant money.
This statement is incorrect by virtue of adding "by any other means".
I'm a firm believer that land use has a pronounced effect on climate however, I have no reason to believe that man-made CO2 emmision has any discernable effect on climate beyond natural variation. Many people who are AGW naysayers don't necessarily believe that human action has no effect on the environment, we simply denounce people who try to state that CO2 drives our climate in the manner in which it's been painted.
Actually you'd increase the specific gravity of the ocean overall if you did that. This is assuming no iron precipitation. An average aquarist would know that increasing the specific gravity of the water by that much would cause massive die offs at the top and would bring a lot of pressure loving life closer to the surface of the water.
Seeing as "dust" is made of organic or silicate based materials which are all lighter than water I don't doubt that they stay in the top few meters and readily dissolve into sea water.
Iron is not lighter than water and it does not readily dissolve into water. This is not an apples to apples comparison.