The oceans are filled with phytoplankton: microscopic plants that are vital to the marine ecosystem because they form the base of the marine food chain. Phytoplankton cannot be seen with the naked eye but from space, satellite images show phytoplankton forming enormous green swirls hundreds of kilometres long in coastal waters. Because phytoplankton consume CO2, increasing their numbers might be a good stratgey for combatting global warming.
"Just like trees, they can take carbon dioxide and give us back oxygen," says Professor Ian Jones, an ocean engineer from the University of Sydney, Australia.
When the plankton die, they sink deep to the ocean floor, taking the carbon with them.
Jones wants to add urea, a components of urine, to the regions of the ocean that lack phytoplankton. Urea is a nitrogen-rich fertiliser that helps plants grow and therefore by adding it to the parts of the ocean that lack phytoplankton, Jones thinks it will turn these areas into a "forest" that will consume vast quantities of CO2, eventually reversing the effects of global warming.
"The important thing about ocean nourishment is that we are not doing it where there is lots of productivity; we are doing it in the desert regions of the ocean," he explains. "If you do not like the outcome, you can turn off the tap. It's like irrigation. When you turn off the food supply for the plankton, they will just die."
But then, there is the problem of meddling with ecosystems that have found a natural balance over millions of years of evolution.
"Once you start managing nature you have to continue to manage nature,' admits JOnes. "There is no use hoping that it will restore itself to a new equilibrium set up by humans."
This is not a new idea. Fifteen years ago there was great interest in seeding the Southern Ocean with iron (it's iron limited) to do much the same thing. I don't think that project met expectations.
This sounds a bit different from the iron experiments, which I beleive increase primary productivity in already productive regions. It is known this works -at least in the short term. If it can be shown that the proposed mechanism will work, and not cause serious problems we should go ahead. The oceans are already being heavily modified -first by overfishing, and now a pulse of CO2 induced acidity, as well as changes in the climatic boundary conditions. If this works (big caveat of course), it might somewhat reduce the later two assaults on the system.
Is there still a risk of oxygen deprivations at lower levels of the ocean from an increased concentration of dead algae? I seem to remember that as being a significant problem in freshwater lakes that resulted in partial bans on phosphates in detergents.
The folks at Deep Sea News aren't too keen on this idea--not because it's meddling, but because they say the carbon will get turned right back into CO2.
Just a thought..the 'dead Zone' ay yhe mouth of Mississippi, in Gulf of Mexico? filled with Nitregen from Ag. runoff, and no life at all!?