Whale Feeds Deep Sea Ecosystem for 50 Years

A whale sinking into the deep sea may have received its last breath, but it's about to feed more than two hundred animal species for 50 years. Yes — entire ecosystems beneath the ocean depend on the slow decomposition of these carcasses.

Feeding the deep: The phenomenon of whale falls

When a whale dies at the sea surface, its massive body descends to the seabed. Most die naturally from old age, feeding a vast array of consumers. It's the kind of feast that plays on a scale only possible in an ocean because the carcasses they leave behind aren't like your typical roadkill. First, scavengers arrive. Hagfish and sleeper sharks are the first to spot a corpse on the ocean floor. They start consuming muscle and fat. They quickly strip the body, leaving a skeleton picked bare. This alone can take several months. Then, the strangest guests come in. Bacteria arrive in earnest, breaking down the fat which remained on the bones. They begin to consume the blubber, slowly converting the blubber into nutrients. They biodegrade the whale's skeleton, creating nutrients available to marine life. After this stage, the body of the whale is so unstable that it is impossible to detect. However, this is precisely when life is given another chance. The massive bones still provide structural support for other organisms. This is when clams and tube worms move in. The whales become a long-term food source for hundreds of species that cannot otherwise be reached by sunlight. This living community is the barest product of soil chemistry, bone marrow, and the remnants of flesh. Without it, the deep sea would be a silent graveyard.

Oases in the desert of the deep

A whale carcass on the ocean floor resembles a bustling city. What starts as a scavenger feast becomes a vestige of life even after most of the flesh is gone. The whale bones serve as feeding grounds and can stay intact for fifty years before they disappear completely. Beneath the waves where there is little to no light, any new source of energy is a goldmine. This is what a whale skeleton offers. But the whale also has its own biologists. Unlike the human ones, which only measured the chemicals of the whale's body, their counterparts in the deep are living, breathing organisms that feed the carcass of the whale. Bacteria use the blubber to convert the oil inside of the whale into a perfect meal for these other organisms. The bacteria are also useful for the whales' underground rehabilitation. Bacteria are the best ones to get at the parts of the whale that remain. Their presence is responsible for the gradual breakdown of the bones. They find ways to consume the parts of the whale that are no longer of any use to the scavengers.

Sucker worms: Whale graveyard scavengers make ramen noodles out of bones

These worms have no mouths, and no stomach, and they eat bones. The worm eats by oozing enzymes to the bone surface, it gets transformed into a liquid. The liquid then flows into the worm, which provides it with food. The enzymes used by the worms are highly specialized and are used to convert the dense fat stored in the whale's skeleton. These enzymes are responsible for the decomposition of the skeleton. The worms use the chemicals they produce to eat the bones of the whale, which are normally quite fibrous and dense. They can be used to break down the lipids stored within the bones, which makes it possible to feed other marine species, all playing the important role of converting energy into a consumable form for these species. The worms are a crucial part of the cycle that helps feed the marine life in the deep sea. The presence of these worms relies on the whale carcasses as a habitat for them so they can perform their function.

The life-cycle of whale bones: Breaking down the food chain

As decomposers, worms and bacteria turn the whale's body into a series of polymers. The bacteria are more specialized and efficient, and they produce enzymes that will break down the bone matrix. This process is slower, but it allows the bones to become nutrient-enriched food. The worms specialized enzymes are broken down into smaller parts that can be absorbed by the worms that will feed on the bones. This process has a chemical reaction that splits the life-giving molecules and nutrients into simpler parts that can be absorbed by the worms. There are a variety of bacteria that can breakdown bone into amino acids. These bacteria eat the bones, and the amino acids produced are used by other deep-sea organisms. In addition, the bacteria break down the bones into their respective amino acids. These amino acids are then absorbed by deep-sea creatures such as the clams, tube worms, and other deep-sea worms. These bacteria are responsible for breaking down the bones, which in turn feed the deep-sea creatures.

How to find a whale fall

Not all whale carcasses reach the sea floor: some sink into the abyss very slowly. It can last up to 50 years, depending on what's eating the whale as it descends. Abigail Alling, who wrote the 2008 book "Whales, Carcass and the Deep Sea", estimated that perhaps 75% of whale carcasses could reach the sea floor before they're consumed. Underwater bubbles are also a good indicator of whale carcasses. A decomposing whale can release gases that produce bubbles underwater. However, it’s important to watch these bubbles, as they can form in a range of places from underwater volcanoes to areas with deep-sea vents. And sometimes the whale may not be at all how you’d imagine it.

The new number is pretty small

The author of a 2021 JGR Oceans article, Craig Smith, said that if whale populations were at 20% of their pre-whaling abundance, the density of whale carcasses on the seabed would be 40% less than it was in the past. Looking forward, bone-eating worms will have much less to feed on. Currently, an estimated 1% of the world’s oceans are home to fewer whales. Thousands of whales die every year, but thousands more are killed by fishermen or stranding on the coast. Smith said that the amount of whale carcasses on the seabed has decreased by 40% since pre-whaling times. This will likely continue to decrease, and there is a risk to the food chain.