Some scientists call it the “Poop Loop” (we dare you to say that with a straight face), while others refer to it as the “Whale Pump.” Whatever you choose to call the magic cycle that keeps our ocean and global climate balanced, it all boils down to the extraordinary power of whale feces.
Meet the Players
The whale pump, or “poop loop,” refers to the exchange of nutrients and movement of carbon through our global ocean, driven by whale excrement. To understand this vital ecological process, we must understand our players:
First, we meet phytoplankton. The colorful world of phytoplankton encompasses a host of bacteria, algae, and certain single-celled organisms capable of converting sunlight into food–a process we all know as photosynthesis. These sun-loving little organisms reside near the ocean’s surface and possess the extraordinary ability to capture extensive amounts of global carbon each year, helping to maintain climate balance. Over millions of years, they’ve also added staggering amounts of oxygen to the Earth’s atmosphere– supporting wildlife and people around the globe.
Then, there’s the zooplankton. This classification consists of larger but still mostly microscopic marine organisms like sea snails, worms, and krill. Most frequently, they feast on phytoplankton– absorbing their carbon and storing it in their small but mighty bodies! Each day, zooplankton embark on the world’s largest migration. During the day, they dive into deep waters, and at night, they return to the surface.
Finally, we meet the great whale. This group includes all baleen whales (including humpback whales, blue whales, fin whales, gray whales, etc.) and the sperm whale. Their massive size awards them this famed moniker, and this immensity in mass can only be rivaled by the enormity of their impact.
How Does the Whale Pump Work?
Whales help breathe life into our planet and keep our ocean’s food web functioning with their poop. Each day, baleen whales dive deep in the water column and eat massive amounts of krill – 5-30% of the whale’s body weight per day, in fact!
The whale then travels back to the surface and introduces deep ocean nutrients through their excrement to the photic zone (the top layer of the ocean). When they relieve themselves, they add nitrogen, phosphorus, and other trace metals, like iron, to the water column. We call these nutrients ‘limiting nutrients,’ meaning that organisms require these nutrients for photosynthesis and other critical biological processes. Their finite availability determines if these processes can take place. Without the presence of whales, these essential ingredients for life are much more scarce, and phytoplankton populations dwindle. Given their migratory nature, whales help boost populations of photosynthetic phytoplankton throughout the entire ocean! These increased populations provide immense support for their zooplankton predators and, in turn, the whales who feast on the zooplankton – rounding out the full whale pump loop!
With their support to phytoplankton, the benefits ripple beyond these three groups of animals. So many more marine species rely on phytoplankton and zooplankton as a food source, and our ocean’s whales support them all!
Why are Whales Important to the Climate Movement?
Through the poop loop processes, whales not only support the stability of the global ocean’s food web, but they also help mitigate climate change. As our climate dioxide input into the atmosphere continues to skyrocket, temperatures rise in tandem. Luckily, phytoplankton are masters at carbon capture. In a study published in 2019 by our Ocean Advisor and friend, Dr. Ralph Chami and his colleagues, it was estimated that across our ocean, phytoplankton capture roughly 40% of all produced carbon dioxide, an amount 4x that of carbon captured by the Amazon Rainforest. So, with their contributions to phytoplankton populations, whales bolster this natural climate change solution!
But the great whale’s support to climate mitigation doesn’t stop with their essential excretions. It’s hypothesized that when phytoplankton consume carbon dioxide, much of the carbon that they don’t use is stored within their bodies. When whales feast on their favorite food, krill, they would absorb the carbon that the krill accumulated from their phytoplankton meals. Whales store carbon in their tissues much longer than smaller marine animals. Then, as a whale’s life comes to an end, they sink to the bottom of the sea. There, hundreds of species live in, and feast on its carcass, and the carbon that was trapped in its body is transferred and sequestered in the seafloor sediments. In doing so, whales greatly aid in our efforts to reduce emissions and support society’s industries like fisheries and tourism with their food web support.
In one lifetime, Dr. Chami and his colleagues concluded in their 2019 study that a single whale introduces an average of $2 million USD of value ($2.4 million adjusted to 2023 USD) to the global economy, and the entire global stock of whales generates over $1 trillion USD.
How can we support this vital ecological process?
Many whale species have been on the rise in much of the world as humanity moves away from destructive whaling practices. However, 300,000 cetaceans still die every year from entanglement, and another 20,000 whales fall victim to ship strikes. Luckily, by creating marine protected area networks, we can grant whales safe passage through the sea, and allow them to aid our changing planet successfully. When we step up for the whales, we step up for countless animals worldwide!
Our team continues to spotlight this invaluable ecological process on large stages.
CNN’s Call to Earth series focused on the whale pump with us and our partners. Follow the great whales and watch the segment here.
In “A Sea of Hope,” we capture the story of the humpback whale, its journey to recovery, and how our team works to brighten this animal’s future. Watch below!
Thank you to our other partners who work to restore whale populations and support the poop loop daily.