On an average day, creatures living in the depths of the ocean rely on ‘marine snow’ – a slow trickle of nutrients from the surface. Every so often, however, a huge feast falls several kilometres through the water and comes to rest on the seabed. The enormous carcass of a whale supports a variety of creatures – from microbes to sharks – for decades, with every part ultimately consumed.
The body of a whale can support millions of deep sea organisms The first hint of the importance of whale
falls came from a paper published in 1900, documenting the discovery of a small mussel clinging to a whalebone picked up by trawlermen. It wasn’t until decades later that the first full skeleton was spotted by divers. At the time they described it as looking like the remains of a dinosaur, but it was soon identified as a whale, and bones were collected for research.
There are three successive stages in the whale fall ecosystem, each made up of a community making use of certain parts of the carcass. The stages can overlap as different creatures are drawn to the scent of the body, but the third and final stage is perhaps the most fascinating; it’s the most diverse community known to exist on the seafloor.
The discovery of large numbers of fossilised clams around 30-million-year-old whale bones suggests that whale fall ecosystems have existed for as long as there have been whales in the ocean. As many of the species found at whale falls are specially adapted to life on whale carcasses, they must travel from
body to body as food runs out in order to survive. While humans rarely come across whale falls, experts believe they might occur as commonly as one every five kilometres off the coast of North America.