Scientists have decoded the potential of the world’s largest animals – whales – to sequester the global warming-inducing greenhouse gas carbon dioxide in the ocean.
Previous studies have found that the planet’s oceans are the greatest carbon sinks which absorb nearly a third of the atmosphere’s greenhouse gas emissions.
In a new study, scientists, including those from the University of Alaska Southeast in the US, analysed the role of whales in the global carbon cycle and how they can potentially contribute to the overall reduction of atmospheric carbon dioxide.
“Understanding the role of whales in the carbon cycle is a dynamic and emerging field that may benefit both marine conservation and climate-change strategies,” scientists wrote.
The entire body biomass of a whale, which weighs up to 150 tons and can live over 100 years, is largely composed of carbon.
Scientists say these ocean giants make up one of the largest living carbon pools in the open seas – a part of the marine system responsible for storing over a fifth of the planet’s total carbon.
“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,” researchers say.
“Considering that baleen whales have some of the longest migrations on the planet, they potentially influence nutrient dynamics and carbon cycling over ocean-basin scales,” they wrote.
Consuming nearly 4 per cent of their massive body weight in krill and photosynthetic plankton every day, a blue whale can eat nearly 8,000 pounds of food in these organisms.
The excrement the whales produce after eating these creatures is rich in important nutrients that help krill and plankton flourish in turn, aiding in increased photosynthesis and carbon storage in the oceans from the atmosphere.
When these ocean behemoths die, their bodies fall to the seafloor and the carbon they contain is transferred back to the deep sea.
However, scientists warn that commercial hunting has decreased whale populations by over 80 per cent, causing unknown effects on the ocean’s carbon nutrient cycle.
“Whale recovery has the potential for long-term self-sustained enhancement of the ocean carbon sink. The full carbon dioxide reduction role of great whales will only be realized through robust conservation and management interventions that directly promote population increases,” researchers wrote.
“We suggest that the precautionary principle be applied to promote recovery of whale populations as a holistic ecosystem goal,” they added.