Carbon Sequestration in Deep Sea Sediments
Researchers from MIT and Harvard hypothesize that deep sea sediments can be used to store large amounts of man-made carbon dioxide. Charles Harvey, who is a co-author of the paper that will appear in this week’s issue of the Proceedings of the National Academy of Sciences, says that CO2 injected into the deep marine sediments is permanently sequestered.
High pressure and low temperature at ocean depths of 3,000 meters or greater provide ideal conditions to store the carbon, say the researchers. Here, the carbon dioxide is in a liquid form that is denser than the surrounding water and has no chance of escaping to the surface.
The researchers claim that the deep sea sediments located within the territorial waters of the United States would provide enough space to sequester the carbon for “thousands of years.”
Wired News had a good article from November, 2004 of carbon sequestration as well.
Related information: Carbon dioxide sink via Wikipedia.
Similar Posts on Geology News:
- Amazon River Carbon Cycle Faster Than Thought
- Sand Avalanches and Sea Level Changes in the Gulf of Mexico
- Marshes Using CO2 to Cope with Global Warming
- Martian Super Geysers
- April Science Picks — Leads, Feeds and Story Seeds
If the CO2 is denser than water, won’t it just sink until it crosses the geothermal boiling level?
Not sure. Since they want to pump it in between sedimentary layers, it won’t really “sink” at all (though I’m not sure what the geothermal boiling level is/means?). Supposedly the pressure of the overlying rock units and water will be high enough to keep this in a perpetual liquid (and therefore more dense) state.
Anyway, I’m really trying not to editorialize articles when I post them, but I don’t know how much I buy their research. Or at least the practical applications behind it. Plus, we know the sea isn’t a static environment anyway (i.e., marine fossils found at the top of Mount Everest, granted something like that takes many tens of millions of years).
From what I gather, they’ll need to have some sort of reservoir to pump the CO2 into. And you’ll need to use quite a bit of energy to either pump the CO2 into the reservoirs at high pressure or convert it to a liquid state and then pump it into the reservoir. So you’ll probably be creating a lot of CO2 in order to bury the CO2.
The geothermal gradient is such that pure CO2 starting at the bottom of a cold ocean should revert to gas because, as it sinks, it will warm faster than it pressurizes.
Presumably only a small subset of available sediments will have the appropriate structure to actually trap fluids.
Just thinkin’.