Reduce CO2 With Phytoplankton Seeding

JediJeremy writes "Nature has this article on a team of scientists who want to reduce the amount of CO2 in the atmosphere by increasing the amount of phytoplankton in the oceans. Phytoplankton thrive on iron, so the scientists are going to conduct a study to better grap the affect of an increase of iron in the water will be. They plan to dissolve an iron sulphate solution in a 150-200 square-kilometer patch of the Southern Ocean, near Antarctica to maximize the containment of the iron. The major flaw in the plan is it will only work if the phytoplankton die and sink to the bottom of the ocean, taking the CO2 with them, otherwise, the carbon will be reintroduced into the ecosystem. Interesting idea, but big design flaw."

Re:Design flaw?

[Radical Rad]

or stuff it in an abandoned mine like they're trying to do with gaseous CO2 already.

I haven't heard about plans to store it in a mine. I have heard several times about sinking it to the bottom of the ocean. That seems like a bad idea to me though. What if something disturbed the ocean like an asteroid strike or nuclear blast? If a lot of CO2 came to the surface at once (in addition to the methane currently locked in ice) it could asphyxiate millions depending on how much was released. Similar things happen frequently in volcanic regions. A CO2 eruption in Camaroon in 1986 killed thousands of people and animals. http://www.geology.sdsu.edu/how_volcanoes_work/Nyo s.html [sdsu.edu]

Re:Design flaw?

[El]

Actually, there is slightly more carbon on Earth than a billion years ago due to meteorite strikes, but the important thing is how much carbon is loose in the atmosphere (C02) versus how much is tied up in the crust of the Earth itself or in other forms. Lately we have been decreasing the biomass tied up in trees (thus releasing carbon into the atmosphere), and extracting and burning hydrocarbons like they are going our of style (which in fact they are). The burning of fossil fuel has a secondary affect noone talks about -- sulpher emissions forms sulphuric acid, which then rain down on limestone and erode it at a much faster rate, thus releasing even more carbon dioxide into the air. If all the photoplankton falls to the bottom of the ocean, it'll eventually form new limestone deposits, no? Perhaps it would be more effective to prevent the limestone we have now from eroding. Ok, who's going to help me spray the Himalayas with a protective sealant?

Re:Design flaw?

[Smidge204]

If you have asteroid strikes reaching the bottom of the oceans or nuclear blasts in just about any form, CO2 probably ain't your biggest problem.

Here's a reference to the abandoned mine storage [abc.net.au] concept.
=Smidge=

Carbon Cycle in National Geographic

[eht]

National Geographic just did an article about the Carbon Cycle [nationalgeographic.com] in their February issue. They stated that this has been tried, but it's been found that most phytoplakton die and decay on the surface without falling to the ocean bottom.

The word is "phYtoplankton"

[Tau Zero]

The word does not derive from "photo", for light, but phyein, to bring forth [m-w.com] via its derivative "phyton". Phytoplankton are the self-feeders, the "autotrophs"; everything else is an other-feeder, or heterotroph.

Thus endeth the grammar lesson for the day.

Re:Design flaw?

[SEWilco]

The ocean bottom already has much more carbon than we might add to it. That carbon is recycled through volcanoes and methane/oil deposits when an ocean plate is subducted and melts.

Look up "carbon budget" to find estimates of where the planet's carbon goes. However, that is also a Kyoto Protocol phrase so you'll have to add planet-related phrases to reduce noise.

Which way you cycle depends on where you are

[Tau Zero]

Unfortunately, your link does not take one to the entire article.

I recall that one such iron-seeding experiment was done in the tropics. One would almost expect the results to be different in the arctic, because cold arctic waters are where the coldest deep-ocean water is formed. If that water is sinking, it seems likely that it would tend to take dead algae with it. (On the other hand, the fact that many Antarctic waters are relatively fertile suggests that there are upwelling currents there which account for the productivity. Perhaps the area being seeded is a downwelling zone... this is not detailed in the article either.)

Re:Earth to Scientists....

[SEWilco]

Well, according to some carbon budget calculations we'll run out of carbon in a few hundred thousand years. Without carbon dioxide in the air, all plants will die. Followed shortly by oxygen-using life forms. I hate when that happens.

Of course, this is a very short time in geologic time scales. Seems unlikely that it would happen now for the first time. This suggests something wrong in such a carbon budget, such as a missing carbon source or overestimated sink. The ocean bottom is one large sink for which values have been hard to calculate...and avoid the common method of "we know the budget must be in balance, so by subtracting the values for all the other sinks, the remainder is obviously the amount of carbon deposited on the ocean floor."

Geritol solution

[SEWilco]

Anyone know if something like this has already been done?

Yes, iron fertilization actually is an idea about 20 years old. "with half a shipload of iron ...I could give you an ice age" [planktos.com]

As the Nature article mentions, smaller experiments have been done. The major question is whether animals might eat all the additional plants. Although if there are then more animals, more of their bones will also be falling to the ocean bottom eventually.

Ways to work around such problems include pulsing the growth. Feed one area enough to increase plant growth, but little enough that the iron will run out soon so that temporary ecology will collapse and more dead things will sink to the ocean bottom.

Sorry already been tested

[TexNex]

The theory was tested by some scientists near the antarctic and while it worked a little the cost of actually doing it is prohibitive. This does not take into account the affect creating billions more of the wee beasites would have on the marine life cycly. Hell the person who first discovered the photopankton advised against this method of using them because of the way negative effects it could have (like feeding alge growth that kills fish). Check out the latest issues of Discover and Scientific Amerian for the lowdown.

Old theory on a new scale

[(0d0]

This has been looked at before (as stated in the article) but only on a much smaller scale. The difference with this project is that they intend to cover a larger area and to watch it for a longer period of time. However, a couple of months will not be long enough to truly judge what sort of side-effects this method may generate.

There is the question of whether the phytoplankton will fall to the ocean bottom and actually remove the CO2 from the system, but this is really less of an issue, I think, because there are many "outs" that the carbon can take to actually fall to the ocean floor. At every step in the food chain things die and float to the bottom or are consumed and excreted and float to the bottom. the general theory is that X% of the biomass will always fall to the ocean floor. If you increase the biomass by a factor of Y, you should see a y-fold increase in flocculation of carbon.

Other questions to consider are what will the effect of an iron enrichment be to other life forms in the same waters? Will the FeSO4 level be toxic to zooplankton or to certain species of fish? Without careful consideration, this process could have devastating effects.

Fortunately, they are practicing good science in that they are testing their theories on (relatively) small scales before beginning a full regimen of iron enrichment to combat a growing problem. This will not solve our problems by any means. It is merely to stem the tide so that better environmental practices can be realized.

Re:"Easy" global solution?

[AuraSeer]

Problem 1: Shallow burial is a very short-term carbon sink. As soon as the buried biomass decomposes, its constituent elements will be released back into the system.

Plankton can be a long-term sink. If a sufficient portion of them do sink to the sea bottom, the carbon can stay out of the system for a geologically significant period.

Problem 2: Speed. Even with optimum fertilization, only so many plants can grow on one acre of land in a year.

Plankton aren't as limited because they live in a three-dimensional environment. That gives them more room to grow and easier access to nutrients.

Problem 3: Efficiency. You'd waste lots of energy on cutting, moving, and burying all those plants. That would require an army of tractors and backhoes and cranes, each of which contributes to the problem.

Plankton doesn't need to be moved or manipulated. A tanker of iron solution could fertilize many, many cubic kilometers of ocean, and the plankton would merrily "harvest" and "bury" themselves without further intervention.