Marine Biomass Regeneration

The idea

Phytoplankton, which are microscopic algae, are the oceans’ primary producers. They do the vast majority of photosynthesis in the oceans, converting inorganic carbon to organic carbon in the ocean.  

Some phytoplankton are consumed by zooplankton and enter the broader food chain. Others stick together to form marine snow – often observed by scuba divers and snorkellers in productive water, like around the UK  – and this slowly floats down into the deep ocean; some of it makes it all the way to the sea floor.

The timescales for the water to come back to the surface are quite long; once the material and the carbon it carries go down into the deep ocean, it can take hundreds to thousands of years before that carbon comes back to the surface. This makes this a long-term removal of carbon from the climate system.

We’re exploring a novel approach to add nutrients to the ocean to stimulate phytoplankton and to increase the natural uptake of carbon by these microalgae. The approach we’re looking at is using “buoyant flakes”: rice husks that are left over from farming and coating them with nutrients that the phytoplankton need. The advantage of this approach is that they can stay floating in the water and slowly release the nutrients to stimulate the algae.  

We’re working as part of a consortium being led by University of Southern California and in conjunction with University of Hawaiʻi, University of Capetown, and National Institute of Oceanography in India.  

The approach is being studied through lab experiments done at our partner institutions. Pericosms (small tanks) mimic what’s happening in the natural ocean, but create a controlled environment where we can study this very closely. The Cambridge group are using numerical simulations to link the experiments together and envision what might happen on a global scale.