How a 15-Year-Old Whale Carcass Is Still Supporting an Undersea Ecosystem
There's a lot scientists still have to learn about the delicate ecosystems found on the ocean's floor. And interestingly enough, a nearly 15-year-old grey whale carcass is helping to unlock secrets of the deep sea.
The approximately 16-meter-long whale carcass was first discovered by researchers from the Monterey Bay Aquarium Research Institute in 2009, at the bottom of the Clayoquot Slope off the coast of British Columbia. The process of a decomposing whale is known as a "whale fall," as the dead animal sinks to the ocean floor where it can provide an "oasis of food supply" to a diverse collection of marine organisms, sometimes for decades.
The area where the carcass is located is known as the Clayoquot Slope Bullseye site, where Ocean Networks Canada (ONC) scientists study how methane gas escapes from the sea floor. However, in visits to the site in 2012, 2020, and now, 2023, the ONC has been monitoring the carcass, to examine the rates of decomposition and degradation and get a better understanding of how marine organisms have evolved since its first discovery.
During the team's latest visit, in conjunction with the Ocean Exploration Trust, they found the skeleton brimming with life 1,250 meters below the ocean's surface, nearly 15 years later. The researchers documented their finding in a video uploaded to YouTube earlier this month.
According to a Nautilus Live blog post, the sea creatures identified living among the remains include several invertebrates and a few fish species, such as gastropods, crab, rattail fish, and tube worms. The tube worms, in particular, were first seen in 2009 and have continued making a home on the left jaw bone of the whale—a "remarkable" finding.
There are four ecosystems stages associated with a whale fall—Mobile Scavenger, Enrichment Opportunist, Sulfophilic, and Reef. In the initial stage, scavengers such as hagfish and sleeper sharks actively consume soft tissue from the carcass. The the second stage sees "enrichment opportunists" colonize the bones with any organic matter left by the scavengers.
In the third stage, which can last up to 50 years, sulfophilic bacteria breaks down the lipids embedded in the bones, which provides nourishment for mussels, clams, limpets and sea snails. Finally, the whale carcass enters the reef stage, in which organic compounds have been exhausted and only minerals remain in the bones, which provide a hard surface for suspension and filter feeders.
It's rare for scientists to get a real-time look at an actively decomposing, which underscores just how important the discovery of the carcass has been.
