Scientists have discovered something they didn't think existed: an animal that can't breathe oxygen, and obviously doesn't need to. Some microbes that don't breathe oxygen breathe hydrogen instead, but there's no evidence Henneguya does this. She suspects that both the salmon muscle and Henneguya's host worm are low-oxygen environments, making the ability to breathe oxygen useless to the organism. These two white cysts in a salmon fillet are typical of the kind the parasite Henneguya forms in the fish muscle. Patrick Keeling, a biology professor at the University of British Columbia has also studied parasitic microbes that don't breathe oxygen, but wasn't involved in the research.

Source: CBC News February 28, 2020 09:00 UTC