Scientists discover new variability in iron supply to the oceans with climate implications

Jul 19, 2013
This image shows a phytoplankton bloom in western South Atlantic Ocean. Credit: NASA

The supply of dissolved iron to oceans around continental shelves has been found to be more variable by region than previously believed – with implications for future climate prediction.

Iron is key to the removal of carbon dioxide from the Earth's atmosphere as it promotes the growth of (phytoplankton), which mop up the and lock it away in the ocean.

A new study, led by researchers based at the National Oceanography Centre Southampton, has found that the amount of dissolved released into the ocean from continental margins displays variability not currently captured by ocean-climate prediction models. This could alter predictions of future because iron, a key , plays an important role in the .

Previously assumed to reflect rates of , the study found that the amount of iron leaking from continental margins (the close to continents) is actually far more varied between regions because of local differences in weathering and erosion on land. The results of the study are published this week in Nature Communications.

"Iron acts like a giant lever on marine life storing carbon," says Dr Will Homoky, lead author and postdoctoral research fellow at University of Southampton Ocean and Earth Science, which is based at the Centre. "It switches on growth of microscopic marine plants, which extract carbon dioxide from our atmosphere and lock it away in the ocean."

Continental margins are a major source of dissolved iron to the oceans and therefore an important factor for climate prediction models. But until now, measurements have only been taken in a limited number of regions across the globe, all of which have been characterised by low and high sedimentation rates. The present study focussed on a region with contrasting environmental conditions – in Atlantic waters off the coast of South Africa.

"We were keen to measure iron from this region because it is so different to areas studied before. The seawater here contains more oxygen, and sediments accumulate much more slowly on the seafloor because the region is drier and geologically less active," says Professor Rachel Mills, co-author at the University of Southampton.

The team found substantially smaller amounts of iron being supplied to seawater than measured anywhere before – challenging preconceptions of iron supply across the globe.

The researchers also identified that there are two different mechanisms by which rocks are dissolving on the seafloor. They did this by measuring the isotopic composition of the iron, using a technique developed with co-authors based at the University of South Carolina.

"We already knew that microbial processes dissolve iron in rocks and minerals," says Dr Homoky, "but now we find that rocks also dissolve passively and release iron to seawater. A bit like sugar dissolving in a cup of tea.

"The fact that we have found a new mechanism makes us question how much iron is leaking out from other areas of the ocean floor. If certain rocks are going to dissolve irrespective of microbial processes, suddenly there are whole regions that might be supplying iron that are presently unaccounted for."

But how much can this one factor really affect changes in the Earth's climate? Dr Homoky explains: "Model simulations indicate that the presence or absence of iron supply from continental margins may be enough to drive Earth's transition between glacial and interglacial periods," he says. "Therefore these findings could certainly have implications for global climate modelling – to what extent, is yet to be determined.

"Our study shows that the amount of iron coming off different margins might vary by up to ten thousand times. In some regions we are probably overestimating – and in others underestimating – the influence of sedimentary iron supply on the ocean's carbon cycle. The goal now is to refine this knowledge to improve ocean-climate models."

Explore further: Sculpting tropical peaks

More information: Nat. Commun. 4:2143 (2013) doi: 10.1038/ncomms3143.

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User comments : 22

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Egleton
2.7 / 5 (16) Jul 19, 2013
I'll come back later to read the inevitable nostril flaring outrage.
freeiam
1.5 / 5 (22) Jul 19, 2013
Don't worry this research has no implication at all, the complete carbon cycle is already known by the all wise IPCC.
They knew this many years ago.
So this research was completely useless.
ValeriaT
1.8 / 5 (15) Jul 19, 2013
this research has no implication at all, the complete carbon cycle is already known by the all wise IPCC

one unexpected implication or iron supply: algae bloom...
deepsand
2.7 / 5 (21) Jul 20, 2013
Don't worry this research has no implication at all, the complete carbon cycle is already known by the all wise IPCC.
They knew this many years ago.
So this research was completely useless.

What is truly useless is this and similar posts of yours.

You lack the humour to be entertaining, the knowledge to be informative, and have all the charm and attraction of a deceased rat which suffered from leprosy and incontinence. One wearies of your constant pecking at one aspect of a subject like an insane woodpecker looking for a grub in a block of concrete.
Neinsense99
2.8 / 5 (18) Jul 20, 2013
Don't worry this research has no implication at all, the complete carbon cycle is already known by the all wise IPCC.
They knew this many years ago.
So this research was completely useless.

I was hoping to find something ironic in this article about iron. Instead, I'll likely find something MOronic in the comments.... Well, that was easy...
Sinister1811
2.8 / 5 (22) Jul 20, 2013
Don't worry this research has no implication at all, the complete carbon cycle is already known by the all wise IPCC.
They knew this many years ago.
So this research was completely useless.


I don't know why Phys.Org doesn't just ban these idiotic rants. I don't even know why these people come here in the first place. A lot of their articles are about climate change. It's like going to the fruit and vegetable section at the supermarket and complaining that it's run by vegans.
antigoracle
1.8 / 5 (21) Jul 20, 2013
Hold on, wasn't the science settled?
No, wait, that was the Convenient Lie to make the False Prophet Gore, the first CO2 billionaire.
Neinsense99
2.8 / 5 (18) Jul 20, 2013
Hold on, wasn't the science settled?
No, wait, that was the Convenient Lie to make the False Prophet Gore, the first CO2 billionaire.

Tide comes in. antigoracle tries tired talking point. Tide goes out. Yawn.
freeiam
1.8 / 5 (20) Jul 20, 2013
Don't worry this research has no implication at all, the complete carbon cycle is already known by the all wise IPCC.
They knew this many years ago.
So this research was completely useless.

What is truly useless is this and similar posts of yours.

You lack the humour to be entertaining, the knowledge to be informative, and have all the charm and attraction of a deceased rat which suffered from leprosy and incontinence. One wearies of your constant pecking at one aspect of a subject like an insane woodpecker looking for a grub in a block of concrete.


Thanks, must have hit a nerve.
I don't like to be lied to, so I guess I keep posting the reasons why IPCC was way to early to conclude what they did base on their 'absolute knowledge' about the carbon cycle.
I guess it's quicksand your in.
freeiam
1.8 / 5 (21) Jul 20, 2013
Don't worry this research has no implication at all, the complete carbon cycle is already known by the all wise IPCC.
They knew this many years ago.
So this research was completely useless.


I don't know why Phys.Org doesn't just ban these idiotic rants. I don't even know why these people come here in the first place. A lot of their articles are about climate change. It's like going to the fruit and vegetable section at the supermarket and complaining that it's run by vegans.


Seems to be there is a lot you don't know; your also not to knowledgable about human rights.
Free speech, if you don't like it, don't read it.
antigoracle
1.6 / 5 (20) Jul 20, 2013
Hold on, wasn't the science settled?
No, wait, that was the Convenient Lie to make the False Prophet Gore, the first CO2 billionaire.

Tide comes in. antigoracle tries tired talking point. Tide goes out. Yawn.

Turd comes up.
Spews the filth, it has been gorging on, from the bottom of its cesspool of ignorance.
Turd goes down.
ubavontuba
1.5 / 5 (17) Jul 20, 2013
"the amount of dissolved iron released into the ocean from continental margins displays variability not currently captured by ocean-climate prediction models. This could alter predictions of future climate change because iron, a key micronutrient, plays an important role in the global carbon cycle.

...'Model simulations indicate that the presence or absence of iron supply from continental margins may be enough to drive Earth's transition between glacial and interglacial periods," he says. "Therefore these findings could certainly have implications for global climate modelling – to what extent, is yet to be determined.'"
This wins the award for the least biased, and best presented climate science I have ever seen presented on phys.org. Excellent work. Truly remarkable, top quality science.

Neinsense99
2.8 / 5 (16) Jul 21, 2013
Hold on, wasn't the science settled?
No, wait, that was the Convenient Lie to make the False Prophet Gore, the first CO2 billionaire.

Tide comes in. antigoracle tries tired talking point. Tide goes out. Yawn.

Turd comes up.
Spews the filth, it has been gorging on, from the bottom of its cesspool of ignorance.
Turd goes down.

I did not use vulgar terminology or personal attacks, but that is something you are evidently incapable of. No surprise. Yawn.
Neinsense99
2.8 / 5 (16) Jul 22, 2013
I'll come back later to read the inevitable nostril flaring outrage.


Hold on, wasn't the science settled?
No, wait, that was the Convenient Lie to make the False Prophet Gore, the first CO2 billionaire.

Tide comes in. antigoracle tries tired talking point. Tide goes out. Yawn.

Turd comes up.
Spews the filth, it has been gorging on, from the bottom of its cesspool of ignorance.
Turd goes down.

It can't go a mile without interjecting it's vile pile of bile. That's just it's style.
Sinister1811
3.1 / 5 (17) Jul 22, 2013
Don't worry this research has no implication at all, the complete carbon cycle is already known by the all wise IPCC.
They knew this many years ago.
So this research was completely useless.


I don't know why Phys.Org doesn't just ban these idiotic rants. I don't even know why these people come here in the first place. A lot of their articles are about climate change. It's like going to the fruit and vegetable section at the supermarket and complaining that it's run by vegans.


Seems to be there is a lot you don't know; your also not to knowledgable about human rights.
Free speech, if you don't like it, don't read it.


Oh really? And what does "human rights" have to do with climate change? Well, I'll let you get back to flaming this discussion anyways.
Howhot
4.4 / 5 (8) Jul 22, 2013
Deep say of @freeaim (but fitting of all the denier)
You lack the humour to be entertaining, the knowledge to be informative, and have all the charm and attraction of a deceased rat which suffered from leprosy and incontinence. One wearies of your constant pecking at one aspect of a subject like an insane woodpecker looking for a grub in a block of concrete.
Lol. It's sooo true. It has the Al Gore Seal of Approval!

The iron concentration in the oceans is important and needs to be understood. Dumping iron into the oceans has been proposed as a means of geo-engineering earths climate (and I think it was even tried in Alaska). To reduce atmospheric CO2 concentrations and reduce the green house effect, the idea was to dump iron dust into large areas of the ocean and create conditions favorable for an Algae bloom. The algae would absorb CO2, dye and sink to the bottom of the ocean, sequestering all of the CO2. It's a fascinating idea for geoengineering the environment.

antigoracle
1 / 5 (14) Jul 24, 2013
Lol. It's sooo true. It has the Al Gore Seal of Approval!

So too does your abject stupidity.
deepsand
2.4 / 5 (14) Jul 26, 2013
Hold on, wasn't the science settled?

You didn't get the memo ... again? And, no, the "my dog must have eaten it" excuse isn't going to work anymore.
deepsand
2.2 / 5 (13) Jul 26, 2013
Don't worry this research has no implication at all, the complete carbon cycle is already known by the all wise IPCC.
They knew this many years ago.
So this research was completely useless.

What is truly useless is this and similar posts of yours.

You lack the humour to be entertaining, the knowledge to be informative, and have all the charm and attraction of a deceased rat which suffered from leprosy and incontinence. One wearies of your constant pecking at one aspect of a subject like an insane woodpecker looking for a grub in a block of concrete.

Thanks, must have hit a nerve.
I don't like to be lied to, so I ...

... just rely on misdirection, obfuscation, and select winnowing to evade the truth.
deepsand
2.2 / 5 (13) Jul 26, 2013
Don't worry this research has no implication at all, the complete carbon cycle is already known by the all wise IPCC.
They knew this many years ago.
So this research was completely useless.


I don't know why Phys.Org doesn't just ban these idiotic rants. I don't even know why these people come here in the first place. A lot of their articles are about climate change. It's like going to the fruit and vegetable section at the supermarket and complaining that it's run by vegans.

Seems to be there is a lot you don't know; your also not to knowledgable about human rights.
Free speech, if you don't like it, don't read it.

It seems that it is you who are ill-informed re. freedom of speech, which is neither universal, without bounds, nor free of burden of consequences.

If you do not like the consequences, then refrain from speaking that which brings opprobrium.
deepsand
2.2 / 5 (13) Jul 26, 2013
Hold on, wasn't the science settled?
No, wait, that was the Convenient Lie to make the False Prophet Gore, the first CO2 billionaire.

Tide comes in. antigoracle tries tired talking point. Tide goes out. Yawn.

Turd comes up.
Spews the filth, it has been gorging on, from the bottom of its cesspool of ignorance.
Turd goes down.

Given that you are our resident expert on fecal matter, spending so much of your time producing such, we'll presume your words to be the direct result of a large body of personal experience.
deepsand
2.2 / 5 (13) Jul 26, 2013
Lol. It's sooo true. It has the Al Gore Seal of Approval!

So too does your abject stupidity.

Who certified your stupidity? Your alma mater, Turd University?