As we all know, carbon is a main contributor to global warming.  Efforts to reduce carbon emissions have been minimal around the globe as of now, but scientists are trying to implement geoengineering techniques to reduce carbon in the atmosphere. One of these geoengineering techniques is iron fertilization in the oceans to increase phytoplankton growth. The iron would promote phytoplankton growth while also taking more carbon from the atmosphere.

The hypothesis is that if we fertilize the oceans with iron, carbon would decrease.  This study suggests that ocean fertilization may only work in the Antarctic area of the ocean.  It was first believed ocean fertilization would work in all iron deficient areas of the ocean, but this may not be the case.  When the scientists looked through ice cores records, they believed an increase in dust (that contains iron) over oceans would also increase phytoplankton blooms. This was not always the case, however. They believe this is due to the ocean lacking other important nutrients. The majority of the ocean is already using up most of these essential nutrients except the Antarctic which means ocean fertilization would likely have to take place there. Antarctic Ocean fertilization experiments have so far provided great progress with a large bloom occurring only two weeks after the ocean was fertilized.

Resource: http://www.scientificamerican.com/article/geoengineering-would-not-work-in-all-oceans/