Persistence of DNA in seawater

Seasonal variability in the persistence of dissolved environmental DNA (eDNA) in a marine system: The role of microbial nutrient limitation

Author: Ian Salter, Ph.D., Faroe Marine Research Institute

Understanding patterns in marine biodiversity and species distribution are important objectives for the effective conservation and management of marine ecosystems. It has recently emerged that most marine organisms leave behind traces of DNA that can be detected in seawater, so called environmental DNA.

Phytoplankton, fish and even whale sharks have all been detected from seawater eDNA samples. However, critical questions still remain about how long this DNA survives in seawater, and therefore over what time and space scales such information might represent. 

In a recently published study, Dr. Ian Salter from Havstovan/iNOVA, measured the persistence of DNA in seawater over an entire year in the NW Mediterranean.  The results show that DNA persistence is seasonal, ranging from several weeks in winter to just a few hours in summer. The persistence of DNA was linked to temperature and bacterial nutrient limitation and could be predicted from a statistical model.  These seasonal variations in DNA persistence need to be accounted for in eDNA assessments of species distribution. The paper is open access and can be downloaded from the PLoSONE website.

Dr. Ian Salter has a project currently funded by Granskingar ra­i­ (2018-2020) that in part will apply the eDNA approach as a component of the Faroese Marine Ecosystem Observing Study (FAMEOS), which aims to establish an observing baseline for marine biodiversity and ecosystem structure in Faroese Shelf waters.