You might think that COMICS is a strange name for a science programme (we should always take science seriously, right?) but it stands for something very important to us and our planet: Controls over Ocean Mesopelagic Interior Carbon Storage.
The ocean stores large amounts of the carbon dioxide that humans put into the atmosphere, helping to regulate Earth’s climate. The ocean storage of carbon is helped along by the microscopic plants and animals that live in the ocean – this is known as the biological carbon pump. Phytoplankton, tiny plants that live in the surface of the ocean, take up CO2 when they photosynthesise. These plants are eaten by zooplankton (tiny animals) which poop out carbon rich pellets which sink down into the ocean. We know that the deeper this organic carbon sinks into the ocean, the longer the carbon is stored there out of contact with the atmosphere. What we don’t know is what controls how deep the carbon gets – is it water temperature? oxygen concentration? ecosystem structure? COMICS aims to find out so we can make better predictions of how carbon storage in the ocean will be affected by climate change.
On this cruise, we’re working in the Benguela upwelling region off the coast of Namibia. Here, cold water comes to the surface along the coast bringing lots of nutrients with it. The phytoplankton form huge blooms which decay as they sink, stripping the oxygen out of the water. The low oxygen means that zooplankton might avoid that part of the water, which could change how deep their poop sinks. During our cruise we’ll measure how much organic carbon is sinking into the ocean, what type of particles there are, and the phytoplankton, zooplankton and bacteria altering the sinking particles. All this will mean we can work out how oxygen concentration affects how deep carbon gets into the ocean's "twilight zone".