Whale poop can be neon green, bright red or even sparkle

How whale poop transformed this scientist’s career

Joe Roman is a conservation biologist at the University of Vermont and the author of ‘Eat, Poop, Die: How Animals Make Our World‘, and ‘Whale‘. He has based his research career on whale feces and has traveled the world collecting samples. His research focuses on how the whales’ waste products bring nutrients back to the ocean’s surface and help to support biodiversity.

As reported here, he first encountered whale poop 30 years ago while working on a right whale research project. On one of his first days on the water in the Bay of Fundy, eastern Canada, they came upon a feeding male right whale with mud on its head—or bonnet—a sign that it had been feeding at the bottom of the bay. It had come up to breathe and rest.

Just before it dove in again, it released an enormous fecal plume. There were gallons of poop in that water. It looked like red floating bricks. The smell was overwhelming. Some whale poop smells like brine and seawater, but with right whales, there’s a strong smell of sulfur.

If you get that poop on your clothes, you have to throw them away. You’re never going to wash it out.

Roman didn’t know it then, but that fecal plume would later spark his global search for whale feces, from Iceland to Mexico, Alaska, and Hawaii.

He has found that whale feces can tell us not only about a whale’s diet but also about its hormones and reproductive status. It can reveal the whale’s stress levels, gut microbiome, and genetic lineage. It even allows researchers to look at the level of mercury and pollution in the ocean—everything from microplastics to parasite loads.

Ambergris, which is formed in the hindgut of sperm whales when they digest squid beaks, is rare and extremely valuable. Since the 1970s, its trade has been restricted in many countries. But in the past, it was used to make perfumes, which were worn by Elizabeth I, Charles I, and Casanova.

Whale fecal plumes can be neon green or bright red. At times, they sparkle with silver scales, like the sun glinting on the water. Every whale defecation is unique.

As for the smell, Roman notes that the poop of right whales is the strongest and foulest, but he has grown to love the smell.

It helped set the course for his research career. Two years after seeing whale poop for the first time, Roman took his first class in marine ecology and learned about one of the most important processes in the ocean, especially in carbon sequestration: the biological pump.

The whale pump represents a crucial but often overlooked mechanism in ocean ecosystems. While the biological pump moves nutrients downward as dead organisms sink to the ocean floor, whales create an opposite flow. These marine mammals dive deep to feed on prey, then return to the surface, where they release nutrient-rich feces.

Their waste contains vital elements like nitrogen, phosphorus, and iron—essential nutrients that would otherwise remain trapped in the deep ocean. When released near the surface, these nutrients become available to phytoplankton, the tiny organisms that form the base of the marine food web.

The phytoplankton bloom, feeding small fish and krill, which in turn support larger fish and more whales. In this way, whale feces act as a biological elevator, moving nutrients upward and sustaining the productivity of entire ocean ecosystems. This discovery challenges the old belief that whales merely deplete fish stocks; instead, their presence may enhance ocean fertility and support larger fish populations.

Phytoplankton, or algae, only grow near the surface of the ocean, where there is enough light for photosynthesis. Animals such as krill and copepods feed on it there, and they are eaten by fish and even whales.

When this phytoplankton dies or is consumed, some of those nutrients are removed from the atmosphere and can sink to the bottom of the ocean. In this way, the biological pump plays an important role in moving carbon to the deep sea.

Roman remembers sitting there in class that day, thinking something was missing. Right whales often feed at depth and poop at the surface, so they’re likely bringing important nutrients like nitrogen, phosphorus, and iron back up to the surface.

That set him off on the idea of a “whale pump,” which researchers have since discovered does the opposite of the biological pump. It pumps nutrients back up to the surface.

These nutrients can get picked up by phytoplankton and go through the entire ocean food chain. This is important because one of the justifications for whaling in Japan, Norway, and Iceland is that whales eat “our fish.” Therefore, if there are too many whales, there will be a decline in fisheries.

The whale pump demonstrates it’s more complicated than that—and that the presence of whales in the ocean might increase fish populations.

As well as helping us to understand the state of the present ocean, whale poop gives us a glimpse into the past ocean and what it was like when there were hundreds of thousands of whales in the sea. If we can restore whales and the nutrient pathways that historically existed through their poop, Roman suggests it could help support more biodiversity in the ocean.