Wave Tribe

Published by Wave Tribe

Fish poop produce nutrients for the survival of other marine organisms
Photo by: Franco Banfi/Biophoto/Alamy

They’re tiny and transparent. They’re only about the size of a human thumb but they happen to be a favorite snack of fish, shellfish, and even birds and seals.

Scientists now believe that these salps, swarming by the billions in hot spots, maybe transporting tons of carbon per day from the ocean surface to the deep sea and keep it from re-entering the atmosphere.

Salps feed on phytoplankton which absorbs carbon through photosynthesis. When salps poo, this carbon is sequestered in their coated fecal pellets that sink rapidly to the bottom of the ocean. Through this mechanism, the carbon is prevented from returning to the atmosphere and instead, is stored on the ocean floor.

Considering that they’ve been around the ocean for millions of years, they’re part of the reason why the ocean is able to absorb excess atmospheric carbon for so long.

Salps maybe transporting tons of carbon per day from the ocean surface to the deep sea

Shrimplike and small, the krill is another organism that may look unremarkable but is a “giant-sized link in the global food chain.”

Because their poo pellets are relatively larger than those of the salp, a swarm of krill can actually sequester a significant amount of carbon in their feces. Because these pellets are heavier, they can sink quickly down to the depths of the ocean where they remain locked down away from the atmosphere.

Young krill are especially important in this carbon sink cycle. Because they live deeper in the water than the adult krill, their poo is more likely to escape the ocean currents that could return the poo to the surface. Instead, it’ll sink easily until it reaches the ocean floor.

Krills can sequester a significant amount of carbon in their feces

Love them or hate them, but they also have a valuable function in capturing dissolved carbon in the ocean.

Sea urchins eat kelp. They help clean up the bottom of the kelp forest by eating the scraps of kelp. They are considered the shredders of the ocean floor. By breaking down the tough kelp leaves, they make it easy for other scavengers to feed on the dead leaves too.

Scientists have discovered that when there are four or more sea urchins per square meter, they were able to consume up to 80% of detritus in shallow reefs. All that kelp carbon naturally went into their feces but the interesting thing is that scientists found out the “export distance” of their poo was increased fourfold.

What this meant is that sea urchin poo is easily transported across longer distances which means it has greater chances of locking the carbon permanently in the deep ocean floor.

Sea urchins' poop is easily transported across longer distances which means it has a greater chance of locking carbon in the ocean floor

Similarly, the same thing is also true for small fishes like anchovies.

When scientists studied the fecal pellets produced by northern anchovies, they found out that the sinking rates for the anchovies' fecal pellets average around 2,500 feet per day.

This means that it takes less than a day for the pellets excreted at the ocean’s surface to sink downwards to the seafloor. Given the right conditions, according to the scientists, fish fecal pellets can transport significant amounts of repackaged surface material to depth, and do so relatively quickly.

Anchovies' poop sink relatively quickly to the
ocean floor

But of course, nothing beats whale poop as carbon sequestering mechanism.

Whales, being the huge gentle creatures that they are, have enormous appetites. And so is apparently their poo.

Unlike other marine organisms, whale poo, or what scientists call faecal plumes, don’t sink. They float. This characteristic allows them to fertilize the oceans because their feces help fuel the nutrient cycle. More feces on the surface means more phytoplankton are able to grow, attracting other species that, in turn, feed on the plankton.

Whale poo can also store a lot of carbon. In fact, scientists have estimated that the poop coming from the sperm whale species alone can sequester 400,000 tonnes of carbon dioxide a year. That’s equivalent to the carbon emissions of 40,000 fossil fuel-guzzling cars.

Which is just one of the many reasons why whales shouldn’t be hunted for food or recreation. They’re very important to the health of our oceans.

Whale poop can store a lot of carbon