Methane-munching crabs may be adapting to climate change: report

Crabs that have a normal diet of plankton have been seen munching on methane-filled bacteria off British Columbia's coast in what experts say could be their way of adapting to climate change.

Researchers with Ocean Networks Canada, an initiative of the University of Victoria and Oregon State University, discovered the snow crabs using other food sources because their main meal may be disappearing with a warmer climate.

The crabs were previously thought to exclusively eat phytoplankton and researchers say this is the first evidence that a commercial species is finding some of its nutrition from other food sources.

The study's co-author, Fabio De Leo, senior scientist at Ocean Networks Canada, says this shows the crabs may be able to adapt if their common food source becomes scarce.

De Leo says that by collecting these specimens, researchers can learn how a variety of sea-dwelling species are adapting to ongoing changes linked to climate change.

"There are other mobile species, not only crabs, but fish species that are commercially harvested. We're excited to start tracking other food webs to see if we find the same signature," said De Leo. 

The crabs have also found a creative way to ingest the methane, De Leo said.

"It was quite funny because of the way the crab accumulated the methane bubbles under its body and kind of lifted off from the sediment, took a turn and flipped head first into the sediment," he said.

The crabs were feeding on methane-processing bacteria in methane seeps, which are found over fissures on the ocean bed. The seeps support a variety of species including clams and mussels that rely directly on the energy provided by such bacteria.