Whales feed deep in the ocean and return to the surface to breath, digest, and, well… poo. The buoyant fecal plumes produced by whales are rich in nutrients such as iron, nitrogen, and phosphorus. These nutrients are exactly what 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.

The nutrients in whale poo and other by-products are also transported across oceans as whales migrate between high latitude feeding grounds and low latitude breeding grounds. This brings an influx of nutrients to otherwise nutrient-poor tropical waters. More nutrients mean more phytoplankton, which in turn absorb more carbon dioxide.

There are still other ways that whales can help trap carbon in the ocean. Through the force of their massive bodies swimming through the water, nutrients are stirred up and brought to phytoplankton. “In addition to being the largest animals on the planet, whales are among the longest-living, with some living over 150 years,” says Heidi Pearson, a marine biology professor at the University of Alaska Southeast and Fulbright Scholar at GRID-Arendal. This long lifespan means that a lot of carbon is trapped in a large whale for a long time. Then, once these animals die, their carcasses sink to the seafloor, bringing a lifetime of trapped carbon with them. Carbon on the seafloor is then essentially buried for thousands to millions of years.

Maria Potouroglou and Dimitris Poursanidis

Mohamed Ahmed Sidi Cheikh and Maria Potouroglou

Miles Macmillan-Lawler