By Allison Albritton, Outreach Specialist
Santiago Herrera, Lehigh University, Co-lead Principal Investigator
Jill McDermott, Lehigh University, Co-lead Principal Investigator
September 23 - 27, 2019
Between September 23-27, 2019, a team of ocean scientists and engineers from Lehigh University and the Woods Hole Oceanographic Institution (WHOI) used NOAA research vessel (R/V) Manta and the newly developed autonomous underwater vehicle (AUV) Mesobot to collect environmental DNA in order to explore the biodiversity of deepwater ecosystems near Flower Garden Banks National Marine Sanctuary in the Northwestern Gulf of Mexico.
eDNA, short for environmental DNA, is the genetic material that organisms leave behind in the water column. As with forensic science, marine species are able to be identified by the invisible signs of their presence constantly being left in the environment.
As part of the Ocean Twilight Zone Project, WHOI researchers Dr. Annette Govindarajan and Dr. Dana Yoerger utilized a novel pumping and filtering system mounted on the Mesobot in order to collect eDNA from seawater while at depth in the Gulf of Mexico. This system was capable of filtering more than 700 liters of water per dive through six independent pairs of filters. eDNA was also obtained onboard R/V Manta by filtering water collected at depth using a rosette of Niskin bottles and environmental sensors. While at sea, filtered eDNA was preserved by freezing.
The expedition included 5 AUV Mesobot dives, yielding a total time in the water of 14 hours 52 minutes and reaching depths of over 365 meters (1,200 feet). A total of 238 eDNA samples were collected during the expedition, including 42 samples taken with the Mesobot and 196 taken from CTD/Niskin bottles deployed from R/V Manta. Back in the laboratories of Dr. Santiago Herrera and Dr. Govindarajan, researchers are using modern gene-sequencing technologies to identify coral, fish, and invertebrate species found in the deep benthic and pelagic Gulf.
Dr. Herrera and Dr. McDermott, in collaboration with Dr. Andrea Quattrini (Smithsonian Institution), Dr. Erik Cordes (Temple University), and Dr. Catherine McFadden (Harvey Mudd College), are also investigating how varying ocean conditions – like temperature, oxygenation, and pH – affect the stability and persistence of eDNA in the deep ocean. Generating a model to estimate for how long eDNA remains in the water column will provide an important framework for marine scientists around the world to use eDNA as an accurate means for studying the biodiversity of deepwater ecosystems.
The results from this eDNA research will be directly applicable to the management and conservation of areas currently being considered for protection as part of the proposed expansion of Flower Garden Banks National Marine Sanctuary.
The expedition was funded by the NOAA Office of Ocean Exploration and Research, grant number NA18OAR0110289 to Lehigh University. Collaborative research conducted during this expedition is also part of the Woods Hole Oceanographic Institution’s Ocean Twilight Zone Project, funded as part of The Audacious Project housed at TED. The Mesobot project was funded by the National Science Foundation program for Ocean Technology and Interdisciplinary Coordination (OTIC) award 1636575. Navigation services for AUV Mesobot were provided by the Undersea Vehicles Program at the University of North Carolina Wilmington.