Multispectral Imaging Broadens Cellular Analysis

How does life begin and evolve? Does life exist elsewhere in the universe? What is the future of life on Earth and beyond?

These questions have lingered for many years, and we still do not fully know the answers to them. NASA, however, in its efforts to sustain life here on our home planet and chart a course for humans to explore the Moon, Mars, and beyond, is going to new depths to better address them—deep beneath the ocean surface.

In the floors of our oceans are holes that spew hot, gaseous, mineral-rich liquids from the deep, subsurface magma below. Scientists from NASA’s Advanced Life Support Group at Ames Research Center are hoping that these holes, called hydrothermal vents, may not only help them unlock the secrets of the deep, but help them learn if exotic life forms exist on other planetary bodies, including Mars and Jupiter’s moon Europa.

Because hydrothermal vents are thousands of meters underwater, they are not exposed to sunlight. Without sunlight, there may be abiotic life forms—life forms that exist devoid of photosynthetic input or decomposition of organic materials—in or near these vents. NASA scientists hypothesize that the deep subsurface of Earth could be home to organisms that exist solely on chemical energy that is generated from the off-gassing magma below the ocean floor. They further hope that this extreme underground environment could provide insight into whether similar life forms exist elsewhere in the universe, in environments that are far removed from the Sun and therefore also require other sources of energy. For example, scientists have targeted Europa because of its thick ice crusts and the mounting evidence that points to there being an ice-covered ocean that could potentially harbor similar hydrothermal vents.

To test their hypothesis, the Advanced Life Support Group scientists have built a life-detection instrument called Medusa to collect, store, and analyze sample organisms from erupting hydrothermal vents. For the sample analyses, Medusa is equipped with a spectralanalysis chemical sensor that uses a process called flow cytometry to examine the natural glow of light, or fluorescence, emitted from any of the samples collected as ocean water flows through the instrument. When the scientists retrieve the samples, they inject a dye into them that interacts with the fluorescence and emits colors to reveal their chemical composition.

Medusa has already been deployed several times to study hydrothermal vents, and scientists will continue to send the instrument to the bottom of the ocean in an effort to validate their theory. NASA also plans to test the instrument in other extreme environments of Earth in its continuing quest to seek unknown life forms. Meanwhile, scientists are working to apply the spectral-analysis capabilities of Medusa’s hemical sensor to other areas of research, especially in studying the effects of gravity and cosmic radiation on human cells to possibly create an enhanced system for monitoring the biological effects of space travel on astronauts.