We know that the world’s forests—boreal, temperate and tropical—play a large role in sequestering carbon dioxide (CO2)—as long as drought, harvesting, insect damage, and wildfires don’t overpower them. But we may have another “champion” helping us to combat rising CO2 levels: whales.
In what’s known as a trophic cascade (defined as an ecological process in which predators in a food web suppress the abundance or alter behavior of their prey, thereby releasing the next lower trophic level from predation or herbivory), whales help to sustain the entire ocean system. While they eat tons of fish and krill every year, whales actually help to keep them alive.
According to the video below, produced by Sustainable Human and published on November 30, 2014, whales feed at depth in waters that are often pitch-black. When they return to the surface, they release fecal plumes rich in iron and nitrogen—nutrients often scarce in surface waters. In this “photic zone” at the surface, there is enough light for photosynthesis to happen, and the iron and nitrogen provided by the whales fertilize the plant plankton living in that sector.
That’s not the only thing whales do to keep plant plankton alive: their plunging up and down kicks sinking plankton back up into the photic zone, giving it more time to reproduce before it drops into the abyss forever. More plant plankton feeds more animal plankton, on which larger creatures then feed. So, it could be argued, more whales mean more fish and krill.
The plant plankton, which proliferates with help from the whales, not only feeds the animals of the sea, it also absorbs CO2 from the atmosphere. When the plankton eventually does sink to the ocean floor, it takes this carbon dioxide down with it, where it will remain for thousands of years. The more whales there are, the more plankton there is. The more plankton there is, the more CO2 is drawn out of the air.
This Sustainable Human video suggests that when whales were at their historic populations, before their numbers were drastically reduced by indiscriminate whaling, they may have been responsible for removing tens of millions of tons of carbon out of the atmosphere every year.
It’s an interesting chain of events to ponder—and the kind of positive, upbeat environmental message we could use a lot more of.
Here’s to finding your true places and natural habitats,