How are scientists using eDNA to learn more about biodiversity in the OTZ?
For the past three years, the OTZ team has been collecting and analyzing eDNA samples along vertical transects in the North Atlantic. These transects extend to the base of the mesopelagic zone (at roughly 1000 meters below the surface). The team is taking samples during the daytime and nighttime in order to detect diel vertical migration, when mesopelagic species migrate to shallow waters during the night and deeper waters during the day. Sampling is guided by shipboard acoustic sensors, which can indicate the presence of different numbers of organisms. The samples are sequenced using genetic metabarcoding approaches to detect a variety of animal types, including fish, crustaceans, and jellyfish.
Back in the laboratory, the team is also conducting experiments to understand eDNA shedding and decay, using a variety of diverse animal forms, temperatures, and light conditions that reflect the mesopelagic environment. They are also working to understand how eDNA moves throughout the twilight zone. OTZ scientists are currently developing new ways to collect eDNA autonomously using platforms like Mesobot (a robot designed for mesopelagic exploration) and Deep-See (a towed broadband acoustics and imaging instrument).