Planting a tree gives you good green karma, but what can you do for your blue, oceanic spirit? Plant a fish. Or encourage whales to poop.
Seriously, whale feces is one of the eight main ways that ocean life collects carbon and creates a better atmosphere, according to Fish Carbon, a new report supported by the United Nations. The report calls it the “whale pump,” and it fascinates grown-up boys.
Here’s underwater photographer Tony Wu’s website on whale defecation. Here’s NPR reporter Robert Krulwich’s story, “The Power of Poop,” complete with a set of his juvenile drawings. Seriously, the drawings are refrigerator worthy.
Just as cow manure helps crops to flourish, whale droppings provide nutrients that spur blooms of plankton. Plankton sits at the bottom of the food chain and feeds everything above, creating that poetic circle of life. Because all life needs carbon, this cycle pulls carbon out of the ocean, which the ocean pulls out of the atmosphere.
The argument of Fish Carbon is that all vertebrates in the ocean, from whales to turtles to fish, provide a major service of carbon sequestration. Their participation in the carbon cycle relieves some of the atmosphere’s carbon dioxide, which is the primary greenhouse gas causing climate change.
The ocean stores about one-third of the world’s carbon emissions, making it a larger sink than rainforests or any land-based system. Research on the ocean’s role in such “blue carbon” has focused on the photosynthesis powers of phytoplankton and coastal mangrove forests. But there’s much more under the surface.
The vertical reach of land-based ecosystems is limited by gravity, but the deep ocean provides miles of vertical habitat. The ocean’s living space dwarfs land, as does its biomass, or quantity of living creatures. That’s a lot of carbon swimming around in the ocean. Kill those fish populations, and we get more carbon stuck in the atmosphere.
Whales deserves special mention for their extreme size and their lifespan, which reaches 200 years for the bowhead whale. The 200,000 tons of carbon trapped annually by sperm whales in the Southern Ocean equals the amount emitted by 18,000 U.S. homes, according to the report by Lutz and Martin.
Sperm whales dive to extreme depths to hunt squid, and they return to the surface to do their business. This process acts as the whale pump that brings deep fertilizer material (poop) into the light.
No one knows how much carbon is stored in all whales and fish, but we now have a place to start. With climate change being driven by carbon dioxide emissions, fish carbon takes on great importance.
Other blue carbon mechanisms include turtles acting as farmers by grazing on seagrass, bony fish excreting calcium carbonate (more power of poop), and migratory movements that stir ocean waters into greater productivity. The opposite is also true: fewer turtles and fish means less productivity and less carbon sequestration.
Twilight Zone Carbon is another mechanism that provides a science fiction twist. The world’s greatest migration takes place nightly as ghostly creatures of the deep ascend to feed and do other business. They work in the opposite direction of whales by transferring surface carbon back into the deep, where it stays put for millennia.
Take a look inside the Fish Carbon report on page 13 for a fascinating graphic that summarizes the various carbon services of ocean vertebrates. Note the brown blotch underneath the whale.
Calling all grown-up kids: This dirty conversation is just getting started.