(ORDO NEWS) — Marine biologists at Southeastern Alaska University have assessed the impact of large whale populations on climate change.
The huge masses of krill that these marine mammals consume and move, and the whales’ own mass, accumulate huge amounts of carbon, which naturally settles in the depths of the ocean. Scientists emphasize that the number of whales directly affects the climate.
Whales are a natural “concentrator” of carbon, they remove it from the atmosphere and “bury” it in the depths of the ocean
With their massive bodies and gigantic plumes of feces, large whales can move massive amounts of organic material across our planet. The researchers suggest that as the population grows, this could make them a major carbon sink.
Marine biologists at Southeastern Alaska University have assessed the impact of these giant mammals on the natural solution to the climate problem.
“Blue whales (Balaenoptera musculus) and fin whales (Balaenoptera physalus) are the two largest animals that have ever lived on Earth,” writes lead author Aidy Pearson.
“Their size and longevity allow large whales to have a strong impact on the carbon cycle. They store carbon more efficiently than small animals when they ingest huge amounts of food and produce large volumes of waste.”
How does a whale carbon pump work
Some whales live up to 200 years, a serious period for a whale-sized ‘chunk’ of carbon to lock up. Every day, a whale eats about 4% of its weight – the mass of food, including krill and plankton, is about 4 tons for blue whales.
The resulting huge amounts of excrement feed the plankton that fix CO2 near the surface of the ocean. Krill feed on this plankton, and then many animals eat the nutrients and carbon along with the krill, including penguins, birds, seals, fish and, of course, the whales themselves.
Studies have shown that even though whales eat krill, higher concentrations of whales often mean higher concentrations of krill in the ocean.
Krill swarms also play a role in the biological carbon pump, as deposits of their own excrement send carbon to the deep ocean.
Before industrial whaling reduced the biomass of large whales by about 80%, whales played a huge role in this fertilization of the ocean.
By some estimates, before the population was virtually wiped out, whales in the Southern Ocean removed about 2 million tons of CO2 per year; now this number has decreased by an order of magnitude and is approaching 200,000 tons.
Giant mammals “recycle” carbon in a more dramatic way: when they die, they sink to the bottom of the ocean.
Here, their biomass becomes food for a range of other animals, but this carbon remains deep underwater.
Helping large whales thrive, of course, will only be part of a much larger network of natural solutions that the signatory states of the Paris Agreement have undertaken.
But “whale recovery has the potential for long-term carbon retention in the ocean,” the paper’s authors conclude.
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