Whale waste fertilizes the ocean, fueling plankton and marine life

Whales do not just eat – they feed the ocean. A new study reveals that baleen whales in the Nordic and Barents Seas can boost summer plankton growth by up to 10 percent, fertilizing nutrient-poor waters with their waste.

The effect appears offshore, well away from other nutrient sources, and aligns with the whales’ feeding season.

The research was focused on waters around Norway and Iceland, where many species gather each summer.

Whale waste feeds oceans

Lead scientist Dr. Carla Freitas of the Institute of Marine Research in Norway (IMR) led the analysis in these high-latitude seas. Her team looked at how whale waste adds missing nutrients to the sunlit surface where tiny plantlike cells live and grow.

Ocean life starts with primary production, the rate at which microscopic algae turn sunlight, water, and dissolved nutrients into new biomass. When those nutrients run short near the surface, growth slows, even when light is plentiful.

In earlier work, biologist Joe Roman of the University of Vermont noted that marine mammals can enhance primary productivity in their feeding areas. Large animals can recycle nutrients in ways that matter at big scales. 

That idea has a clear mechanism. Whales feed at depth, return to the surface to breathe, then release waste that stays suspended long enough to be used near the light.

What is in whale waste?

The group sampled feces and urine from baleen whales and mapped where those nutrients would go. They found that urine carries most of the nitrogen, while feces carry more phosphorus and trace metals.

Earlier field data show that minke whale feces off Svalbard concentrate nitrogen and phosphorus far above background seawater. That pattern helps explain why even small inputs can spark growth in nutrient poor surface layers.

Daily outputs per whale are not trivial. A typical minke releases roughly 17.6 pounds of dry fecal matter and about 26.7 gallons of urine each day.

For a fin whale, the numbers climb sharply with body size. That means fewer big whales can still deliver a hefty pulse of nutrients to open water.

Trace elements matter as well. Recent work reports organic ligands in whale feces that keep iron dissolved and tame copper’s toxicity.

Keeping iron in forms that algae can use is a quiet advantage. It helps explain why fecal plumes can be more than just a short lived burst.

Whales spark plankton blooms

The modeling points to offshore basins as the main beneficiaries. There, whale nutrient release fills a gap that rivers and coastal mixing cannot reach.

Timing is key. The biggest bump occurs during stratification, a seasonal layering of warm, light surface water over colder, deep water that slows vertical mixing.

In the Nordic and Barents Seas, that layering builds through summer. As surface nutrients become scarce, a small, steady top-up can have an outsized effect.

The result is a stronger seasonal peak in open water. The boost to growth reaches as much as 10 percent in August, when demand is high and background supply is thin.

Ripples through ocean life

More plant growth means more food for grazers. The model predicts a rise in mesozooplankton – small drifting animals about two-tenths to two millimeters long – by as much as 10 percent.

These grazers move energy up the food web. Fish that feed on them can grow faster, and so can the species that eat those fish.

The effect is most noticeable where other inputs are weak. Offshore basins and areas near the summer ice edge show the clearest signal. It is a subtle nudge, not a wholesale change. But in ecosystems governed by tight nutrient budgets, small nudges matter.

Whales move ocean nutrients

Whales do more than fertilize the surface where they feed. They also carry nutrients across basins when they migrate from rich, cold waters to tropical nurseries.

A 2025 analysis estimates that migrating baleen whales transport thousands of tons of nitrogen each year to low-latitude seas. That flow likely ran stronger before modern whaling.

Oceanographers sometimes call this a conveyor. It connects seasonal hotspots to distant nursery grounds through the bodies of the animals themselves.

That connection adds to the summer pulse described here. Together, recycling and transport help stitch the ocean’s nutrient budget across space and time.

Questions in the model

The annual average effects in the model are modest across most of the region. They grow in summer, then fade as winds and storms remix the surface in fall.

Some model settings still need tighter bounds. For example, the fraction of fecal nitrogen and phosphorus that dissolves versus sinks likely varies by prey type and particle size.

The depth of urine release is another open question. The model assumes most release occurs near the surface, which fits how these animals spend their time.

Ratios among nutrients – called stoichiometry, or the balance of elements cells need to grow – can also shift plankton communities. Different mixes can favor different winners even at the same total supply.

Ocean nutrients from whales

Not all nitrogen is equal in how quickly algae can use it. Urine supplies dissolved forms that cells can take up quickly in bright summer light.

Phosphorus in feces can still be useful if it dissolves before sinking. That depends on particle makeup and how fast surfacing currents spread the plume.

Iron is often scarce in open seas. Keeping it dissolved with organic ligands, as shown in recent paper results, helps it stick around long enough to matter. Those chemical details are not footnotes. They set the rules for who grows, how fast, and for how long.

Whale waste fuels life

This new modeling builds on more than a decade of field evidence. Early shipboard experiments showed that whale waste releases dissolved nutrients fast enough to feed blooms near the surface.

“Marine mammals can enhance primary productivity in their feeding areas,” said Roman. The core finding from 2010 still holds true.

Follow-up work linked waste chemistry to growth bursts in specific places. Those examples match the hotspots this model identifies offshore.

Together, the evidence supports a simple idea: healthy whale populations help maintain healthy, productive seas when nutrients run short.

The study is published in Proceedings of the National Academy of Sciences.

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