Marine Environmental DNA (eDNA) is the study of the genetic material shed by passing marine life. Once sequenced, a scientist can determine which species were present.
Previously, the only way to do this would be to send a trained observer overboard in SCUBA gear. Even then, there were limits to how deep a study could be done, and there's always the problem that a human garbed in SCUBA gear, with its Darth Vader-like sounds, could send a shy fish fleeing. By contrast eDNA can see everything at every depth. The tool is so powerful that it frequently indicates the presence of salmonid DNA in the Gulf of California, even though there is none in the area. Where does that DNA come from? I leave it to your imagination.
However, there are limits. There are millions of species on the planet, but only a fraction have had their genetic material sequenced, so a scientist has to rely on libraries of known genomes. Because many species are very closely related, their genomes may have slight differences, so differentiation down to the species level can be difficult (but frequently unnecessary).
For Leg 2, we have Dr. Adrian Munguia-Vega, an eDNA scientist with an appointment at the University of Arizona. He also has a small lab in La Paz that specializes in genetic population studies. He has been taking eDNA samples everytime we put a CTD package over the side, so we will have genetic information along with basic oceanographic information.
While the technology is incredible, the process is actually a pretty simple one.
It's used to collect a water sample at a specific depth.
is vulnerable to being contaminated by any passing life,
including humans. It was a windy day, so
a towel was used to shield the butane lighter.
What's left behind is what is sequenced.
The nearest road is about 40 miles away.
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