Environmental Dna in an Ocean of Change: Status, Challenges and Prospects

Abstract

Environmental DNA (eDNA) studies have burgeoned over the last two decades and the application of eDNA has increased exponentially since 2010, albeit at a slower pace in the marine system. We provide a literature overview on marine metazoan eDNA studies and assess recent achievements in answering questions related to species distributions, biodiversity and biomass. We investigate which are the better studied taxonomic groups, geographic regions and the genetic markers used. We evaluate the use of eDNA for addressing ecological and environmental issues through food web, ecotoxicological, surveillance and management studies. Based on this state of the art, we highlight exciting prospects of eDNA for marine time series, population genetic studies, the use of natural sampler DNA, and eDNA data for building trophic networks and ecosystem models. We discuss the current limitations, in terms of marker choice and incompleteness of reference databases. We also present recent advances using experiments and modeling to better understand persistence, decay and dispersal of eDNA in coastal and oceanic systems. Finally, we explore promising avenues for marine eDNA research, including autonomous or passive eDNA sampling, as well as the combined applications of eDNA with different surveillance methods and further molecular advances.
 Keywords: environmental DNA, DNA metabarcoding, marine metazoa, biodiversity, population genetics, natural sampler DNA, diet analysis.

Environmental DNA Metabarcoding: A Novel Contrivance for Documenting Terrestrial Biodiversity

“…These pioneering investigations are well-defined and could not be possible to explore without the introduction of eDNA metabarcoding [ 57 ]. Conventional techniques for studying biodiversity help assess and recognize the threats to global ecosystems, with rapidly evolving innovative techniques like eDNA providing novel prospects for all-encompassing biodiversity research besides proving to be a proficient and cost-effective method for evaluating the ecosystem structure and functioning [ 58 , 59 ].…”

Pan‐Arctic distribution modeling reveals climate‐change‐driven poleward shifts of major gelatinous zooplankton species

“…These shifts may lead to a potential displacement of local fish populations and affect the carbon cycle and trophic dynamics. To fully understand such potential impact, it is necessary to gain a more detailed understanding of their population dynamics and their role in the food web, using novel techniques such as molecular analyses (Havermans et al 2022). In order to assess their interactions with arctic and boreal fish stocks, comprehensive long-term and cost-effective monitoring programs involving the fishing industry are needed (Aubert et al 2018).…”

“…Gelatinous zooplankton span different trophic levels and are characterized by a wide array of ecological habits, hence, poleward expansions of suitable habitats of the different gelatinous zooplankton taxa studied will result in a myriad of potential impacts on the energy flow, trophodynamics, and biogeochemistry in Arctic Ocean ecosystems. At first, we need to better understand their population dynamics, by obtaining accurate estimates of their abundance using modern technologies including pelagic video surveys (e.g., Pantiukhin et al 2023), and environmental DNA methods (Havermans et al 2022). Given the expected expansion of gelatinous zooplankton, fisheries need to incorporate these dynamics into their management plans, preventing major impacts on fish stocks, and potentially leading to stock collapses as witnessed elsewhere in the world (Richardson et al 2009).…”

Autonomous eDNA collection using an uncrewed surface vessel over a 4200‐km transect of the eastern Pacific Ocean

“…Despite the promise of eDNA, the vastness, and inaccessibility of much of the world's oceans make it difficult to obtain representative samples on meaningful scales (Havermans et al, 2022).…”

“…Despite the promise of eDNA, the vastness, and inaccessibility of much of the world's oceans make it difficult to obtain representative samples on meaningful scales (Havermans et al, 2022). Historically, eDNA sampling in the open sea has relied on crewed vessels, which adds considerable cost and logistical challenges for implementing routine, open‐ocean eDNA biomonitoring programs (Compson et al, 2020).…”