Recent evidence suggests that life originated in extreme environments, for example, at high temperatures. The National Science Foundation (NSF) has initiated a program called Life in the Extreme Environment (LExEn) that is dedicated to finding new and exciting organisms that live in harsh environments.

The Extreme 2000 research expedition, at hydrothermal vent sites in the Sea of Cortés, is led by marine scientists George Luther and Craig Cary from the University of Delaware and Anna-Louise Reysenbach from Portland State University. Their chief objective is to make real-time chemical measurements at the vents using microsensors developed by Dr. Luther’s group, which will guide the microbiologists and molecular biologists in Dr. Cary’s and Dr. Reysenbach’s groups in finding organisms that are descendants of early life forms.

Chemical Detective Work at the Bottom of the Sea

Are hydrothermal vents home to the closest relatives of the oldest life on Earth? Using special tools housed in a wand on the sub Alvin, researchers will be testing the chemistry of vent water in search of microscopic organisms. The wand houses a thermometer, an apparatus called “the Sipper” to collect small water samples, and a super-sensitive chemical analyzer.

The analyzer is like a sophisticated underwater “snooper.” It can be used near the vents and, from its chemical readings, tell scientists what kind of microbes might live there. While our food chain is based on energy from the sun, the sun’s rays never reach the deep sea. There, organisms must rely on a different energy source: the chemicals that rocket out of the vents.

During a previous expedition, the Extreme 2000 scientific team found that the presence of two compounds — hydrogen sulfide (H2S) and iron monosulfide (FeS) — may be an important indicator of the oldest microscopic vent life. These compounds react to form the mineral pyrite (“fool’s gold”) and hydrogen gas. The hydrogen provides the energy that these microbes need to grow.

With the analyzer’s help, marine scientists may be able to track down the nearest descendants of the first life on Earth, and perhaps on other planets.

Europa, one of the moons of Jupiter, is covered in ice. However, recent findings suggest that portions of the ice move, which is strong evidence that liquid water lies beneath the ice. The water may be maintained in its liquid state by hydrothermal vents. If hydrothermal vents exist on Europa, there’s a possibility that ancient microbes could live there, too.