Researchers from the Max Planck Institute of Marine Microbiology and the Center for Marine Environmental Sciences (MARUM) have discovered a third form of energy that powers the likes of certain mussels, shrimp, and worms found in the surroundings of hydrothermal vents. Earlier discoveries of chemosynthesis at the vents included sulfur oxidation and methane oxidation systems, but now it appears that the creatures oxidize hydrogen too - and a lot of it!
Hydrothermal vents spew hot minerals into the sea from newly formed crusts in the earth: © MARUM
Discovered some 30 years ago, hydrothermal vents are created at the depths of the ocean floors where tectonic plates have shifted and, like an underwater volcano, spurt tremendously hot, dissolving minerals into the sea. As hot as 400°, the inorganic compounds delivered by the liquid minerals provided energy for life through a process called chemosynthesis.
The first two sources of energy discovered to power chemosynthesis at hydrothermal vents were hydrogen sulfide and methane, each utilized by animals with symbiotic oxidation systems. But this latest discovery led by the Max Planck Institute found that the deep vent mussels, shrimp, and the giant tubeworm at Logatchev, a vent field halfway between the Caribbean and the Cape Verde Islands on the Mid-Atlantic Ridge, were powered by hydrogen.
Assisted by remotely-driven submersible excavators, researchers took live samples on board their ships and conducted experiments showing that the mussels consumed hydrogen. In their land-based labs, they discovered that the mussels had a key enzyme for hydrogen oxidation, the symbiont hydrogenase.
Mussels at the Logatchev hydrothermal vent site are powered by hydrogen: © MARUM
In fact, the hydrogenase proved to be more powerful than the hydrogen sulfide and methane in converting geofuels to biomass in the Logatchev region. One researchers estimated that the population of some 1/2 million mussels could be consuming up to 5,000 liters of hydrogen per hour.
Maybe some day we will run our cars on mussel power....