The Whale Pump: Whales fertilize the ocean. Through vertical movements and nutrient-rich feces, they recycle iron, nitrogen, and phosphorus back to the surface, stimulating phytoplankton blooms that capture CO₂ and fuel marine food webs.
The Whale Pump: Giants as Ocean Gardeners
Whales fertilize the ocean—recycling iron and other nutrients that power blooms, feed food webs, and help the ocean capture carbon.
Whales as Iron Recyclers: In the Southern Ocean, baleen whales consume ~190 million tonnes of krill each year. This converts ~7,600 tonnes of iron locked in krill into nutrient-rich feces, releasing bioavailable iron back into surface waters and boosting productivity.
Whale Feces: Natural Fertilizer: Whale feces can contain iron concentrations over 10 million times higher than seawater. Defecation near the surface returns this bioavailable iron to the photic zone, helping phytoplankton grow and supporting the entire ecosystem.
Upward vs. Downward Pumps: Zooplankton and fish drive the downward biological pump, sending carbon to depth via sinking particles. Whales power an upward pump—recycling nutrients to the surface via feces and urea—enhancing primary production.
The Cost of Whaling: Industrial whaling reduced Southern Ocean whale populations by over 99%, removing an estimated 1.7×10⁷ tonnes of carbon from marine ecosystems and weakening these natural fertilization pathways.
Whales are ecosystem engineers and climate allies. By restoring whale populations, we can revive nutrient recycling that stimulates phytoplankton, supports fisheries, and strengthens a nature-based pathway for ocean carbon capture.