Elizabeth Ellison

Carbon dioxide sequestration through ocean fertilization and potential for harvest of calcium carbonate from marine organisms

Started: October 2018

Supervisor: Dr Ali Mashayek; Prof Chris Cheeseman

Description of Research

The ocean is the largest global reservoir of carbon, containing more carbon than the atmosphere or the terrestrial biome. The primary way that carbon is taken into the ocean is through the biological carbon pump (BCP) where phytoplankton in the surface ocean photosynthesise, taking carbon dioxide (CO₂) from the atmosphere and fixing it into the ocean. In many areas of the ocean, photosynthesis is limited by the low levels of iron present in the ocean. Therefore a novel form a geoengineering, ocean iron fertilisation, has been proposed to mitigate rising atmospheric CO₂ levels by removing atmospheric CO₂ through enhanced photosynthesis, and storing it in deep ocean sediments.

In this study we will use an ocean global circulation model (MIT GCM) to examine if the addition of iron to certain regions of the ocean could enhance productivity and the biological carbon pump, increasing the amount of carbon removed from the atmosphere and sequestered into the deep ocean. We will also examine the effect that this iron fertilisation could have on regional ecological structures and on global nutrient cycles.