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Hanging over the side of the boat, Nahi El Bar Jiyed scoops up a jug of sea water, then carefully pours it into a large syringe. While the sample may seem ordinary, to the biologist it’s a trove of secrets: the DNA of every living creature swimming below.
He presses the water sample through a filter about the size of his hand, which captures the DNA fragments, then repeats the process several more times. Meters away, a sea turtle emerges for a breath then retreats to the seagrass meadow below.
“Without disturbing the environment, we can take a sample that tells us exactly what was at…
