A world without light
On February 17, 1977, a team of scientists in the deep-sea submersible Alvin descended 2,500 meters into the Galápagos Rift, a boundary between tectonic plates. They were searching for predicted underwater hot springs, but what they found was completely unexpected. In the near-freezing 2-4°C water, they located vents shimmering with superheated fluid up to 350°C. Surrounding these vents was an oasis of life. The most striking organisms were clusters of giant tubeworms, Riftia pachyptila, with white tubes up to 3 meters long and bright red plumes swaying in the currents.
This discovery at the site, later named the Rose Garden, presented a deep puzzle. Photosynthesis, the process that uses sunlight to create energy, is impossible in this deep, dark environment. Scientists soon realized this entire food web was based on a different process: chemosynthesis. Instead of sunlight, the primary producers are bacteria that harness chemical energy from the vents, specifically from hydrogen sulfide. This finding changed the understanding of where and how life could exist on Earth. The expedition, which was initially a geological mission, had no biologists on board because no one believed complex life could survive in such conditions.