A decade-long marine experiment off the coast of British Columbia has raised alarm among scientists.
After it failed to detect a key deep-sea species known for decomposing whale bones, scientists are warning that their absence may signal an ecosystem collapse triggered by climate change.
In an experiment, researchers from the University of Victoria and Ocean Networks Canada (ONC) placed humpback whale bones nearly 1,000 metres below the surface at Barkley Canyon, approximately 100km southwest of Tofino.
After monitoring the area for 10 years, using high-resolution underwater cameras, scientists found no traces of the Osedax worm – nicknamed the “zombie worm” or “bone devourer.”
This finding, or lack thereof, has proven to be troubling, said ONC senior staff scientist Fabio De Leo, noting it may be explained by the low concentrations of oxygen present at the observation site.
Despite having no mouth or digestive system, Osedax worms bore their root-like structures into bones, extracting nutrients with the help of bacteria. De Leo added that their role is critical in recycling whale remains and supporting deep-sea biodiversity.
Whale carcasses, sinking to the seafloor, provide rich food sources that can sustain unique marine communities for decades. However, the absence of zombie worms points to a breakdown in this process.
Barkley Canyon is located in a naturally low-oxygen zone which researchers say is expanding as the oceans warm. These expanding oxygen minimum zones, driven by climate change, are reducing habitat viability for species such as Osedax and wood-boring Xylophaga bivalves, another key decomposer that was found in unusually low numbers during the study.
“Basically, we’re talking about potential species loss,” De Leo said, adding that adult Osedax, who grow on whale bones, spawn their larvae that drift long oceanic currents to colonize other whale falls. “These island habitats will not be connected anymore, and then you could start losing a diversity of Osedax species across regional spatial scales.”
Preliminary data from another ONC research site suggests the decline may not be limited to one location.
Researchers will release additional findings from an ongoing whale fall study at Clayoquot Slope in the coming months.