NOAA 'Omics Seminar Series (September 27, 2023): Exploring Ocean Biodiversity with eDNA

Date: September 27, 2023
Title: Exploring Ocean Twilight Zone Biodiversity with eDNA
Presenter: Dr. Annette Govindarajan
Abstract: The ocean’s mesopelagic zone (or “ocean twilight zone”) harbors a vast biomass that is critically important to the global carbon cycle. However, the diversity of this biomass is understudied due to the OTZ’s immense size and the logistical challenges of sampling the environment. There are knowledge gaps related to the composition, distributions, and ecological interactions of mesopelagic biomass. More information is especially needed on the phenomenon of diel vertical migration (DVM), where typically animals travel to surface waters to feed at night and return to mesopelagic depths for the day, expediting the downward movement of carbon in the process. Environmental DNA (eDNA) analyses have great potential to provide information on OTZ biodiversity and address hypotheses related DVM, species distributions, and ecological interactions. However, animal eDNA signals in the deep ocean are dilute and patchily distributed, creating challenges for using eDNA in the OTZ. I will discuss recent advances in eDNA approaches to studying OTZ animal diversity, including considerations for sampling, analysis, reference databases, and interpretation of results. I will also discuss autonomous sampling strategies, including the importance of large volume sampling and the integration of samplers with diverse oceanographic platforms, including Mesobot, a robot designed to sense and track midwater animals and particles, and Deep-See, a towed broadband acoustics and imaging instrument. I will describe our recent deployments with these platforms, and present results on mesopelagic animal diversity and DVM