Catching the Blooms

by srosengard

Yesterday, March 20, was the first day of Austral Fall (and Springtime in the U.S.!), as well as was the last pump deployment for Phoebe, Dan and me in our cruise across the southern Indian Ocean. Just after surviving a rather rough day on the ocean, we reached this last mega-station in the morning with clear skies, warmth air, and gentle rolls. Fortunately, this was an easier ending than I could have asked for.

Standing nearly at the finish line of our expedition, I think it gives perspective to remind myself why we spent 5 weeks crossing one of the harshest oceans in the world.

If I really were to get at the root of things, we are all here for the coccolithophore. There is just about as much to coccolithophores as there are syllables in their name (to be accurate, however, there is more to them than the name itself). They are microscopic organisms living at the ocean surface that produce skeletons of calcium carbonate, or calcite. The calcite on their bodies is the same mineral shallow-water corals use to build their famous reefs across the world.

While coral have global recognition, coccolithophores received their fair share of limelight on the Revelle as well. Every Austral summer, the coccolithophore populations at the surface of the Southern Ocean surface explode. These coccolithophore blooms can be seen from satellites. They are strong but fast, magnificent but transient. As a result, while there are many good questions to ask about these blooms, the in-field oceanographer must get the timing right in order find the right answers. Catching the bloom is particularly challenging on a research cruise; it is one limited and expensive shot at a remote and quick phenomenon.

A bigger scientific question, larger than our cruise, is what causes coccolithophore blooms. For Jason Hopkins, Helen’s seafaring scientific companion, that question is at the heart of his research in his first year at University of Southampton. Unsurprisingly, there are many ways the oceanographer can answer this. For instance, from a chemistry perspective (my perspective in training), field scientists might measure the abundance of nutrients in coccolithopohores and their surrounding seawater. Assuming coccolithophores are what they eat, us chemists presume that blooms analogously arise from the presence of certain dissolved elements in the ocean.

In oceanography, things often follow a chain. Knowing the cause for coccolithophore blooms might help explain their greater effects on the oceans. Given the size of these blooms, these ocean-based effects could have consequences for other parts of our planet, like our atmosphere or climate. Coccolithophore communities, especially in bloom period, are huge storage houses for carbon in several forms. There is carbon in their calcite shells. There is carbon in their organic  tissue. Where it ends up—in the ocean or as an atmospheric greenhouse gas—is a motivation for many, including myself, to study the coccolithophore’s role and, also importantly, to learn how to pronounce their name.

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