A new concept, 'fish carbon’, recognizes the potential of marine life to address the climate change challenge and prevent global biodiversity loss. ‘Fish carbon’ is a term used to describe the carbon interactions of all marine vertebrates that contribute to the oceans’ carbon sequestration: turtles, sea birds, mammals such as whales and dolphins, and fish such as sharks, tuna and sardines. These interactions or mechanisms are the natural life processes of marine life that enable capture of atmospheric carbon, allow carbon storage in benign form deep in the ocean, and provide a potential buffer against ocean acidification.

An example is the vital role whales play in the ecology of the ocean. Whales eat a lot and excrete enormous quantities of nutrients that help phytoplankton grow. When whales swim from ocean depths to the surface, they also increase nutrient availability for phytoplankton. Like plants on land, phytoplankton absorb carbon dioxide. More phytoplankton means more carbon dioxide removed from the atmosphere. Whales are also big and long-lived. This means they store a lot of carbon in their bodies, and for long periods of time. When they die and sink to the ocean floor, they bring all of that trapped carbon with them where it can remain buried for millennia.

Much work remains to measure the value of whale carbon and harnessing it for climate change action. However, the majority of countries that have endorsed the International Whaling Commission resolutions clearly indicate that there is great potential interest in the role that whales and other marine life can play in combating climate change:

“Whales feed deep in the ocean and return to the surface to breath, digest, and poo. The buoyant faecal plumes produced by whales are rich in the nutrients that phytoplankton need to grow and thus, importantly, absorb carbon dioxide in surface waters, allowing for more carbon to be naturally drawn into the oceans from the atmosphere.” – Heidi Pearson, marine biology professor at the University of Alaska Southeast and Fulbright Scholar at UN Environment/GRID-Arendal.

“Recognizing the role marine life may play in mitigating climate change may help small island developing states, especially those who are large ocean nations, include ocean actions in their Nationally Determined Contributions under the Paris Agreement,” – Ronald Jumeau, Permanent Representative to the United Nations and Ambassador for Climate Change for the Republic of Seychelles.

Further reading

Business unusual: How fish carbon" stabilizes our climate 

How whale poo is connected to the climate

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Who would have guessed that the impacts of whaling would cascade through so many living systems?