With Earth’s carbon dioxide levels having just reached 400 parts per million we need to start finding reasonable solutions for addressing this problem. A biologist named Victor Smetacek of the Alfred Wegener Institute for Polar and Marine Research thought up a controversial yet innovative idea to help reduce CO2 levels in our atmosphere. His idea is called ocean fertilization. Ocean fertilization is the process of “fertilizing” the ocean with iron sulfate (dust) in order to induce algae blooms. These blooms would then absorb the CO2 from the atmosphere and slowly begin to die off and sink to the bottom of the ocean.
To understand the need for more iron in our ocean, one must understand the history of our ocean’s iron. During our last ice age, about 20,000 years ago, there was four to five times the amount of iron in the Southern Ocean than there is today due to dust traveling from Patagonia. It makes sense that there is less iron in the Southern ocean today due to there being a lot more ice than dust. Victor deigned ocean fertilization to bring back algal blooms to the iron deficient Antarctica and in return lower CO2 levels.
To test his theory, Victor and some partners designed an experiment in which they would be able to test the CO2 levels before and after the algae bloom. Victor dumped seven tons of iron into a controlled ocean space for several weeks and successfully induced an algal bloom. Victor calculated that the seven tons of iron spread out over some 167 sq kilometers would closely replicate the wake of a melting iceberg. (.01 gram of iron per sq meter.) After two weeks he found that the algae had, “…induced carbon to fall 34 times as fast as natural rates for nearly two weeks—the highest such rate ever observed outside the laboratory.”(Scientific American) He then stopped supplying the plankton with iron and they sank to the ocean floor with the absorbed CO2.
Although this experiment is still in its early stages, there are still a few questionable aspects of adding large amounts of iron into the ocean. The first potential problem is marine health. When algae bloom they can produce large dead zones or red tides that negatively affect the local ecosystems. Next is that the absorbed CO2 that sinks could rise back up to the surface through ocean currents and return into the atmosphere. In order to sufficiently reduce CO2 we would need to produce many algal blooms throughout the world. So we must ask ourselves if this is enough. I believe that ocean fertilization has the future potential to successfully reduce CO2 for good. Yes, there are some questions that pertain to marine health, and overall effectiveness, but with some time to design the right technologies and the right locations, we can use algae to our advantage to help lower global CO2 levels through earth’s natural processes.