Ocean Carbon Removal Methods- An Introduction

The reason why water is so central to life is because of its marvelous solvent capabilities. Oceans have taken up the clean up job by dissolving a third of the carbon dioxide emitted in the atmosphere since the industrial age. The carbon in the atmosphere is in equilibrium with the carbon in the oceans. Emitting carbon in the air, thus, increases its concentration in the water. 

Take a deep breath. The source of that inhaled oxygen was likely a phytoplankton. Phytoplanktons are microscopic organisms that absorb sunlight and produce organic matter at the top layers of the ocean. This organic matter is consumed by another set of microscopic organisms called zooplanktons. These along with the cute dolphins and the gigantic whales comprise 300,000 of the marine species known to us.

Marine species follow the same process of growth and decay as life on land. They use carbon dioxide to create organic matter which is used by organisms later in the food chain. Ocean carbon dioxide removal (CDR) approaches involve increasing the ocean’s capacity to take up more carbon. This can be achieved in two ways. 

The first one involves increasing the ocean ‘productivity’ by making it more fertile. This includes approaches such as improving ocean nutrient profile resulting in increased Phytoplankton growth. Other approaches in this category include seaweed farming and mangrove restoration. A vibrant marine life takes up more carbon dioxide from the water which is replaced by carbon dioxide from the atmosphere to maintain the equilibrium.

Another set of approaches involve modifying the solvent properties so that oceans can dissolve more carbon dioxide. These include ocean alkalinity enhancement and electrochemical methods. 

Many effects of these methods on the ocean ecosystem are unknown and there remains an uncertainty around the actual amount the carbon sequestered. Nevertheless, the oceans, due to their vastness, provide a great potential in reaching our CDR goals.