The effect of tides on nearshore environmental DNA

PeerJ. 2018 Mar 19:6:e4521. doi: 10.7717/peerj.4521. eCollection 2018.

Abstract

We can recover genetic information from organisms of all kinds using environmental sampling. In recent years, sequencing this environmental DNA (eDNA) has become a tractable means of surveying many species using water, air, or soil samples. The technique is beginning to become a core tool for ecologists, environmental scientists, and biologists of many kinds, but the temporal resolution of eDNA sampling is often unclear, limiting the ecological interpretations of the resulting datasets. Here, in a temporally and spatially replicated field study using ca. 313 bp of eukaryotic COI mtDNA as a marker, we find that nearshore organismal communities are largely consistent across tides. Our findings suggest that nearshore eDNA from both benthic and planktonic taxa tends to be endogenous to the site and water mass sampled, rather than changing with each tidal cycle. However, where physiochemical water mass characteristics change, we find that the relative contributions of a broad range of organisms to eDNA communities shift in concert.

Keywords: Ecological communities; Metabarcoding; eDNA.

Grants and funding

This work was made possible by grant 2016-65101 from the David and Lucile Packard Foundation to Ryan Kelly. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.