Unexpected Life at the Galápagos Rift
For two million years, Earth has been inhabited by living things that make their own food. Known as the producers of their communities, these self-sufficient life forms convert substances from their immediate environment into energy-rich food molecules.
The energy they pack into these molecules has to come from somewhere — and while we have long known that plants and chlorophyll-carrying microbes harness energy from the sun via photosynthesis, a new type of producer was discovered a bit less than a half-century ago. Curiously, these new specimens live in the complete absence of sunlight — and somehow make their own nutrients.
Chemosynthesis
The first of these microbes to be discovered was found living in the pitch darkness of the ocean floor near hydrothermal vents — fissures in the earth’s crust where an upwelling of liquid-hot magma meets seawater, forming a chemical-rich soup. While bursting with geothermal energy, the resulting mixture is toxic to most living things.
One of the compounds in the mix is hydrogen sulfide (H₂S) — for us, a fairly nasty chemical that is deadly at even low concentrations. And yet, many microbes on the ocean floor happily consume it. In doing so, they pluck electrons off of their hydrogen sulfide molecules, mix in a little carbon dioxide and water, and fix the…
