Whale breaching at Stellwagen Bank National Marine Sanctuary. Credit: Whit Welles
Key Points:
- The recovery of whale populations by reducing anthropogenic impacts can aid in the removal of carbon dioxide.
- Their size and longevity allow whales to exert strong effects on the carbon cycle by storing carbon more effectively than small animals.
- Whale recovery has the potential for long-term self-sustained enhancement of the ocean carbon sink.
A new study by researchers at the University of Alaska Southeast has found that whales can influence the amount of carbon in air and waters, and potentially contribute to the overall reduction of atmospheric carbon dioxide.
Whales can weigh up to 150 tons, live over 100 years, and be the size of large airplanes. Like all living things, their hefty biomass is composed largely of carbon and they make up one of the largest living carbon pools in the pelagic ocean, part of the marine system that is responsible for storing 22% of Earth’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," write the authors. "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."
Whales consume 4% of their body weight daily in krill and photosynthetic plankton, which equates to approximately 8,000 pounds in the blue whale. Their excretion after food digestion is rich in essential nutrients that aid in the flourishing of krill and plankton, thus enhancing photosynthesis and carbon storage from the atmosphere.
When blue whales die, their bodies fall into the seafloor and decay; the carbon is discarded into the deep sea, thus supplementing the biological carbon pump. Nutrients and chemicals are then exchanged through biogeochemical pathways. Commercial hunting has, however, reduced the whale population by 81%, contributing to effects on the biological carbon pump.
Researchers, however, note that the inclusion of whales in climate policy can only be successful if grounded in the best available science and considered in tandem with strategies known to reduce greenhouse gas emissions directly.
"Whale recovery has the potential for long-term self-sustained enhancement of the ocean carbon sink," the authors write. "The full carbon dioxide reduction role of great whales (and other organisms) will only be realized through robust conservation and management interventions that promote population increases.”