Buzz
Whale carcasses take decades to fully decompose and can provide sustenance for an entire ecosystem deep beneath the ocean floor.
Whales are always known as one of the largest marine creatures, occupying a high position in the food chain. With their massive weight of hundreds of tons, the death of a whale raises many questions. The sight of a whale dying in the wild is rare, so scientists have few opportunities to study dead whales sinking naturally into the ocean.
Dr. Adrian Glover, a marine biology expert at the Natural History Museum (UK), has shed light on the afterlife of whales. Even in death, they provide sustenance for hundreds of marine creatures for up to 50 years. Thus, whales play an immensely important role in the Earth's oceanic lifecycles.
Whales are the 'ocean's big brother,' the largest creatures beneath the sea.
Similar to many other animals, decomposition begins immediately after a whale passes away. Subsequently, the carcass expands with gas and sometimes floats to the surface, where it can be consumed by sharks and seabirds.
Ultimately, the ocean giant will begin its descent, dropping from one kilometer to the next until finally resting peacefully on the seabed.
Notably, after death, a whale's carcass becomes incredibly valuable. It can nourish the entire deep-sea ecosystem, from large scavengers to tiny bacteria. They provide the inhabitants of the virtually deserted ocean floor with a sudden and abundant food source. Whales are crucial to the marine ecosystem, and this discovery underscores their significant role in Earth's oceanic lifecycles.
A 50-year feast for the entire ocean
Once a whale descends to the ocean floor, blind fish, sleeping sharks, crabs, lobsters, and a plethora of other scavengers will feast on its blubber and flesh down to the bone. A single whale can provide sustenance for the entire animal ecosystem in this initial 'garbage collection' phase for up to two years.
Large scavengers can turn a carcass into a pile of bones, but there's still plenty of food for much smaller 'diners.' Threadworms like Vigtorniella flokati feast on the tissues of deceased whales, reducing the carcass to bare bones. Sea snails, bristle worms, and shrimp will gulp down any remaining fat or flesh. They'll also consume organic matter excreted from the flesh. Bone-devouring worms (Osedax) were first discovered on a 3 km deep whale fall in 2002.
Adrian explains: 'These are the most important creatures responsible for the bone decomposition process. Also known as bone worms, these invertebrates chemically consume bone, breaking down components like collagen and fat using specialized methods. Additionally, they push oxygen into the bones, a process that accelerates decomposition. These small scavengers can take up to 10 years to harvest a whale carcass.'
Unexpected Discovery
While scavengers work to digest the bones, whales also provide a more specialized form of sustenance that scientists have recently uncovered.
Dead whale bones are inhabited by bacteria that produce hydrogen sulfide, a foul-smelling gas. There's a process called chemosynthesis where animals derive energy from this chemical and others, rather than through food. Soft-bodied animals and tube worms are chemosynthetic creatures that exploit whale carcasses, feeding on chemicals released from the bones.
Before whale falls were extensively documented, it was believed that this biological diversity was only seen in cold seeps and hydrothermal vents, where hydrogen sulfide and methane gas naturally seep through sediments. But now it's acknowledged that whale carcasses provide a unique stepping stone for specialized species from these locations to disperse throughout the ocean floor, especially in remote areas.
What if whales die stranded on shore?
However, not all whales sink to the ocean floor when they die.
Instead, some become stranded on coastlines worldwide. While humans often attempt to rescue them, without water to maintain the buoyancy, the whale's body weight will soon begin to crush internal organs.
The 100 tons of decaying flesh from a beached whale is a 'scientific goldmine' - a fantastic opportunity for researchers to study a creature typically out of reach.
Source: NHM, The Guardian
