Suggested Searches

2 min read

Spotting a Single Microbe in a Grain of Ice

The headshot image of Aaron Gronstal

Aaron Gronstal

Jun 14, 2024
Article

New study finds that future missions to icy ocean worlds might be able to use spectrometry to spot a single bacterial cell in a single grain of ice.

A spacecraft hovers over a reddish striped moon with planet Jupiter in the background.
An artist's concept of NASA's Europa Clipper spacecraft.
NASA/JPL-Caltech

NASA-supported scientists are among a team of researchers who have examined whether or not future missions to icy ocean worlds could spot a single bacterial cell, or just small pieces of bacteria, in a single grain of ice using mass spectrometry.

When NASA’s Cassini mission flew past Saturn’s moon Enceladus, the spacecraft spotted plumes of material emitting from the tiny moon. The source of this material is thought to be Enceladus’ subsurface ocean. Similar features could exist on other icy ocean worlds, and being able to analyze such material in detail could allow astrobiologists to determine the habitability of subsurface oceans, and maybe even spot biosignatures.

Backlit plume erupting from Enceladus
The geyser basin at the south pole of Saturn's ocean moon Enceladus as seen by Cassini in 2014.

By obtaining mass spectra resulting from impacts of ice grains containing single bacterial cells (or fractions of cells), researchers were able to determine how bacteria in ice grains from ocean worlds might look to instruments on future missions, such as the SUrface Dust Analyzer (SUDA) onboard NASA’s soon-to-launch Europa Clipper.

SUDA sits on a metal table in a clean room lit in purple light. The instrument is a gold drumlike shape on its side with it's hatch closed like a lid.
Europa Clipper’s SUrface Dust Analyzer (SUDA) sensor head is shown in a clean room at the Laboratory for Atmospheric and Space Physics (LASP) at the University of Colorado Boulder.
NASA/CU Boulder/Glenn Asakawa

Based on the results, the team believes that future instruments similar to SUDA could identify spectral characteristics of bacteria (or tiny pieces of bacteria) in plume material. This is the case even when a spacecraft is taking measurements while flying past a world at speeds of 4 to 6 kilometers per second.

NASA’s next mission to an icy ocean world is the Europa Clipper, scheduled to launch later this year. Europa Clipper is not a search for life mission, but it will attempt to determine whether there are places below the surface of Jupiter’s icy moon, Europa, that could support life.

An illustration of Europa Clipper over Europa with Jupiter in the background.
Download the "Journey to an Ocean World" desktop wallpaper.
NASA/JPL-Caltech

The study, “How to identify cell material in a single ice grain emitted from Enceladus or Europa,” was published in the journal Science Advances.

In a previous study, NASA-supported scientists also looked at how instruments like SUDA could be used to identify transition metals in ice grains, providing clues about the oxidation state of subsurface oceans. This information could help scientists understand whether or not hydrothermal processes play a role in ocean chemistry and ultimately the habitability of such worlds. The study “Probing the Oxidation State of Ocean Worlds with SUDA: Fe (ii) and Fe (iii) in Ice Grains,” was published in The Planetary Science Journal.