Thursday June 1, 2023
EurekAlert! —
Beneath the surface of a freshwater stream, animals, plants, fungi, and microorganisms create complex patterns of biodiversity. Brooke Penaluna, research fisheries biologist at the USDA Forest Service Pacific Northwest Research Station, studies these dynamics, which can be complicated.
“Understanding the biodiversity of freshwater ecosystems and how different species are distributed along a stream network is challenging. Streams are interconnected and have a lot of rare and hard-to-detect species,” said Penaluna.
A sculpin — a prickly, bottom-dwelling fish species.
Penaluna and her research team studied four headwater watersheds of the Trask River in coastal Oregon. Their study relied on analysis of environmental DNA (eDNA), which are traces of genetic material shed by living organisms into the stream. From their water samples, the scientists extracted minute bits of DNA and sent them to a lab to be sequenced, providing a genetic signature. Their samples contained over 2 million sequences or “reads,” which then had to be compared to known genetic databases to determine the identity of species.