Storing and capturing carbon dioxide (CO2), the most common of greenhouse gases, is a crucial part of curbing global heating. This process, called carbon sequestration, is typically talked about in relation to planting trees or restoring wetlands but less so with mammals.
But researchers have found that some of the planet’s largest mammals can potentially contribute to overall reduction of CO2 in the atmosphere.
Whales can weigh up to 150 tons and, like all living things, are composed largely of carbon. It makes them one of the largest living “carbon sinks”.
The ocean is an important carbon sink, absorbing around one-fifth of human-caused carbon emissions over the last decade.
Blue whales, for example, eat around 8,000lbs of small crustaceans, krill, and photosynthetic plankton every day. In turn, whales’ excrement is rich in nutrients that help tiny sea creatures to flourish, supprting photosynthesis and carbon storage, the scientists found.
“Their size and longevity allow whales to exert strong effects on the carbon cycle by storing carbon more effectively than small animals, ingesting extreme quantities of prey, and producing large volumes of waste products,” wrote the research team from the University of Alaska Southeast and the University of Otago. The new paper was published this month in the journalTrends in Ecology and Evolution.
Whales can live for nearly a century and when they die, their bodies fall to the seafloor where carbon is transferred to the deep sea as they decay.
This adds to the biological carbon pump, where nutrients and chemicals are exchanged between the ocean and the atmosphere.
The scientists say that protecting whale populations and helping increase their numbers is important in enhancing the ocean as a carbon sink.
Commercial hunting has done untold damage to the biological carbon pump by decreasing whale populations by 81 per cent.