One method of carbon sequestration, which has not yet been discussed on this blog, is that of ocean fertilization. This idea has generated a great amount of controversy, primarily because of its potential implications for marine ecosystems and biodiversity. Debates about ocean fertilization center around uncertainty of the efficacy of the method in terms of sequestration, the potential of this method to threaten biodiversity and alter ocean ecosystems, and the various ethical dilemmas surrounding this action. While comprehensive coverage of these and other issues surrounding ocean fertilization deserve (and certainly have) blogs of their own, The Emission will at the least give a basic explanation of this carbon sequestration method.
Let's start with the basics. Oceans host an incredible variety of plant and animal forms, and right around the base of the food chain is phytoplankton. These tiny plants (which, as you may remember from grade school, are the main course for baleen whales) float around near the surface of the ocean and take up CO2 in the process of photosynthesis. As with most creatures, there are a few key nutrients that phytoplankton need to survive. One of these is iron.
In a few ocean basins, most notably the Southern Ocean, the number of phytoplankton living there is limited by the availability of iron, in other words, there isn't enough of this macronutrient to go around. The idea behind ocean fertilization, therefore, is to dump iron into regions like the Southern Ocean in order to stimulate phytoplankton growth and enhance CO2 uptake, as a result of more photosynthesis taking place in the surface waters. Those who support this method say that, upon death, phytoplankton will sink to the ocean floor to be buried as marine sediment, effectively putting fossil-fuel derived carbon back into underground storage. The great uncertainty is whether or not this actually occurs, or whether respiration and other processes simply put the CO2 back into the air, or leave it dissolved in ocean waters (which has its own set of complex consequences).
This idea has become a hot topic among those seeking a profit through sales of carbon offsets. Because of the extremely controversial nature of this method, however, there has yet to be a large-scale trial of ocean fertilization. Planktos was a hopeful upstart, with grand plans to seed the ocean waters near the Galapagos Islands, but because of difficulty in garnering support for such a contentious proposal, they were forced to file bankruptcy.
Let's start with the basics. Oceans host an incredible variety of plant and animal forms, and right around the base of the food chain is phytoplankton. These tiny plants (which, as you may remember from grade school, are the main course for baleen whales) float around near the surface of the ocean and take up CO2 in the process of photosynthesis. As with most creatures, there are a few key nutrients that phytoplankton need to survive. One of these is iron.
In a few ocean basins, most notably the Southern Ocean, the number of phytoplankton living there is limited by the availability of iron, in other words, there isn't enough of this macronutrient to go around. The idea behind ocean fertilization, therefore, is to dump iron into regions like the Southern Ocean in order to stimulate phytoplankton growth and enhance CO2 uptake, as a result of more photosynthesis taking place in the surface waters. Those who support this method say that, upon death, phytoplankton will sink to the ocean floor to be buried as marine sediment, effectively putting fossil-fuel derived carbon back into underground storage. The great uncertainty is whether or not this actually occurs, or whether respiration and other processes simply put the CO2 back into the air, or leave it dissolved in ocean waters (which has its own set of complex consequences).
This idea has become a hot topic among those seeking a profit through sales of carbon offsets. Because of the extremely controversial nature of this method, however, there has yet to be a large-scale trial of ocean fertilization. Planktos was a hopeful upstart, with grand plans to seed the ocean waters near the Galapagos Islands, but because of difficulty in garnering support for such a contentious proposal, they were forced to file bankruptcy.
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