Humpback whales could be growing their own food supply and fighting climate change in a very unusual way — with their poo. Biologists are conducting Alaska research this summer on what’s called the “whale pump hypothesis.”
The first time Dana Bloch ever saw a whale, she was in Provincetown, Mass. with her grandfather.
“I would usually fall asleep on the whale watches — I think, because it was a long boat ride out there,” Bloch said. “It was sunny and rocking. And when I was about 7, I was like: ‘I’m gonna stay awake and I’m going to see all the whales and spot them first!’”
And it was humpbacks in particular that Bloch fell in love with.
“They’re so, kind of like lumpy, bumpy and gangly,” said Bloch. “And they have this ridiculous shape. They’re mysterious and under the water, like they’re just these giant mammals like blobbing around doing really cool stuff.”
Two decades later, Bloch crossed the continent to study some of that cool stuff going on under the waves, as part of a postgraduate degree at the University of Alaska Fairbanks. Bloch said the whale pump hypothesis she’s investigating has four steps.
“Step one is: The whale is feeding on nutrient rich prey,” Bloch said. “And that could be krill, herring, maybe juvenile salmon or sand lance. Step two is the whales returned to the surface and they produce a fecal plume in the surface water.”
Bloch said the best way to spot a plume — or in layman’s terms, “a giant cloud of whale poop” — is from a drone.
“It’s like a red cloud that’s kind of coming from underneath the whale’s tail,” she said. “It usually comes as the whale dives.”
But it’s what the poop contains that really matters.
“Step three: The material in the whale poop is very rich in nutrients,” Bloch said. “In Southeast Alaska we’re mostly interested like phosphorus and nitrogen.”
And finally comes step four.
“Phytoplankton are using the nutrients to grow and reproduce,” said Bloch.
So, there you have it: the four steps of the whale pump hypothesis.
Bloch said there are two reasons why should we care about phytoplankton. The first is that they are the base of the ocean food chain. Everything else relies on them, including the fish that whales eat. And that’s why Bloch said humpbacks could be like gardeners of the sea.
“It’s like they’re fertilizing the area where their food may be growing,” she said. “And in that sense, the whales may be kind of in less competition with the fisheries or with other ocean needs than we sometimes think.”
And the second reason we should care about phytoplankton is even more important.
“They’re primary producers that are responsible for about 50% of the oxygen in the air,” Bloch said. “So they’re responsible for every other breath you take.”
Some estimates of phytoplankton’s global oxygen production run even higher, and Bloch said their output rivals that of trees.
“Trees produce a lot of the oxygen, but the oceans are giant and cover most of the earth,” said Bloch.
Plus, when the phytoplankton die, they sink to the bottom of the ocean, storing all that carbon far away from the surface. Now, superhero phytoplankton sound really cool — but Bloch’s job is a little less glamorous. She works with the Alaska Whale Foundation out of Warm Springs Bay to collect the data she needs. She has a video of herself hanging off the side of the boat with a white net in her hand.
“When the drone pilot says like ‘Okay, go ahead,’ I drop a small phytoplankton net into the water and just run it through the fecal plume,” Bloch said. “I pull it out and transfer that into a bottle and put it in the freezer next to our frozen berries.”
“What does it smell like?” a reporter asked.
“It smells awful,” Bloch said. “It smells like fishy poop. I mean, it is fishy poop, so…”
Bloch said that there’s lots more work to be done in the future. But when she’s out on the water, Bloch thinks back to her grandfather’s boat in Massachusetts.
“And if I told my 7-year-old self, I wouldn’t have believed myself then because it’s just, like — that’s way too cool,” said Bloch.
Bloch will continue her research until the spring of 2024 — so there’s plenty of time for her to fully digest all the data she collects this summer.
