Breathing oxygen is rather fundamental for life on Earth, it's something that you may even take for granted. All multicellular animals on this planet require oxygen in order to survive. That is, until scientists from Tel Aviv University discovered at least one that doesn't need it.
This jellyfish-like parasite doesn't have a mitochondrial genome, which means it doesn't breathe. In fact, it lives its entire life without breathing.
The findings were published in PNAS.
How does an animal survive without breathing?
"It has lost the ability to breathe oxygen," said Dorothee Huchon at Tel Aviv University in Israel. It's still a mystery how this animal, a parasite that latches onto salmon, survives life without oxygen. However, scientists believe it most likely finds a way to steal it from its host.
Up until this parasite, it was widely believed that all animals and plants needed oxygen in order to power their cellular processes. The generation of this energy happens in structures called the mitochondria.
Each mitochondrion has its own genome, but when Huchon's team observed the Henneguya salminicola DNA, related to jellyfish, they found no mitochondrion at all. In fact, they believed they had made a mistake, so proceeded to carry out further studies, all of which reached the same conclusion: no DNA appeared outside the nucleus.
This means the salmon parasite can survive entirely without using oxygen.
Nick Lane of University College London told NewScientist that "There are plenty that can go for extended periods without, but nothing that can get through the whole life cycle."
That is to say, nothing that has yet been confirmed. Back in 2010, a team led by Roberto Danovaro at the Polytechnic University of Marche in Italy discovered a group of tiny animals called loriciferans that live in the depths of the Mediterranean Sea that also had no visible mitochondria.
Danovaro's findings have been questioned by fellow biologists that state that further genomic studies need to take place on loriciferans before this can be confirmed.
It's still unclear why H. salminicola don't need oxygen in order to live. Luckily, these parasites are harmless to humans, however, they're a pest for fish farmers as they create unsightly white spots on the infected salmon.