Mining Ancient DNA From Mississippi River Delta Sediment to Establish a Novel Geohistorical Archive of Coastal Installation Sensitivity

ABSTRACT The objective of this work is to demonstrate that sedimentary ancient DNA can be recovered from coastal sediments and reliably differentiated from living components in those sediments. Novel field, laboratory, and bioinformatic techniques developed for ancient environmental DNA (aeDNA) isolation in wetlands will allow the reconstruction of entire ancient coastal communities of all trophic levels. A large proportion of the 27 million acres of land managed by the DoD includes coastal, riverine, and estuarine ecosystems which are dominated by wetlands [1]. There is a need to develop robust, long-term baselines of coastal ecosystem disturbance to understand regime shifts that could lead to land loss and irreversible damage to DoD installations and infrastructure. Efforts are already being made within DoD to leverage nature to improve battlefield and installation performance, but design goals are only as good as our ability to engineer toward “ideal” environmental conditions [2]. Exploiting the environmental intelligence stored in the sediments of lakes, wetlands, and peatlands may be an effective tool to improve benchmarking and reduce uncertainty in installation management and design. The MRD was selected as our study site because each delta complex represents a well-constrained segment of the Holocene, with the intention that aeDNA technology developed here can be transferred to other DoD-relevant landscapes. This project will use sediment cores from the MRD spanning >6 kyr to demonstrate that aeDNA can be recovered and distinguished from modern DNA to reconstruct ancient ecosystem composition throughout MRD formation in the Holocene.