Ashley,
What you say is no doubt true in some parts of the oceans, but in the basic Oceanography course I took the instructor made it clear that much of our oceans are essentially dead zones because none of the nutrients found at 400 or so feet below the surface are rising to the surface.
The energy required to move the nutrient laden seawater 400 feet down is slight because so little real work is required. If we were looking to lift the water above sea level a lot of energy would have to be expended, but pumping it from 400 feet down to just below the surface would require very little energy as all you must overcome is the density difference, and minor friction losses through the pipe if velocity is kept low.
There are many ways of moving the water, perhaps the easiest to put in place would be something constructed similar to the hose used on a laundry dryer where compressed a section that expanded to say 500 feet long would only be perhaps 25 feet long. If one end is weighed down with an intake fitting and the other end is attached by a number of lines to a buoyant collar with sufficient buoyancy to keep the hose from sinking the vehicle's in place for bringing up the nutrient laden seawater. Add some additional buoyancy and you can support batteries, solar and/or wind generators, and some sort of pump or compressor.
I tend to like the idea of a small fairly low pressure air compressor which would introduce compressed air bubbles perhaps 15 or so feet down the hose. The air bubbles rising to the surface would carry water with it in the same manner many aquarium filters circulate water with compressed air. Aerating the nutrient laden seawater would probably make it somewhat less dense, but it would be the ocean currents and wind that hopefully would spread the nutrients for miles before they diluted and sunk.
I certainly don't know how well this can work, how much area a single such unit can enrich, but even if tens of thousands of this sort of unit were needed to make the oceans dramatically more productive, wouldn't it be worth it if we not only eliminated much the excess CO2, but also dramatically added to the fish population. It wouldn't happen instantaneously, but first you build up the plankton population at the surface of the ocean, then you build up the population of the fish and other animals that feed on plankton, and finally you build up the population of the fish and other animals that feed on the plankton eaters.
I know this is overly simplistic, Oceanographers and engineers would need to optimize this, and much might involve experimentation on a variety of sights, but conceptually each unit need not cost that much. Once the design is optimized, mass production can make the costs even more reasonable, and ultimately after sufficient units were in place, the only cost would be maintainance as solar and/or wind power would do everything.
Gary |
