From Pacific deep sea trenches to the Cornish Coast, eDNA revolutionises our understanding of marine life. This new technology, which enables to identify what organisms exist in an area of the ocean by extracting traces of DNA from the water, comes just in time…
…because we are changing the marine environment before we know it.
On land, many countries require the undertaking of an environmental impact assessments (EIA) for large developments. True, in some cases they are still ‘paper tigers’ and profit comes before environment. But elsewhere, meaningful mitigation measures suggested by EIAs are implemented and compensate for some of the environmental damage caused by the development.
The situation in the ocean is more complex. The equivalent to terrestrial EIAs also exist for marine structures and energy projects. However, even within the boundaries of territorial waters (12 nautical miles) or contiguous zone (24 nm), and certainly over the extent of the continental shelf [1], the complexity and spatial variability of marine ecosystems remains poorly understood. New technologies help address this [e.g. 2, 3, 4].
The oceans amount to 95 percent of Earth’s living space and yet, deep-sea landscapes and ecosystems are among the least explored on Earth, with less than 0.0001% physically sampled or visually observed [5]. What we know so far paints a picture of a multitude of different and interconnected deep-sea habitats of high biodiversity, while our understandg of their composition, diversity, function and vulnerability remains limited [6].
On the other hand, whether on shelf seas or in the abbyss, we are damaging habitats and threatening ecosystem functioning through destructive fishing practices and by-catch, pollution, ocean warming, deep-sea mining, krill harvesting, noise, vibration and sonar, coastal development, global shipping and terrestrial run-off [7, 8, 9, 10, 11, 12, 13].
Marine scientists are in a race against time: whether their efforts are to map the ocean floor, explore deep-sea habitats or investigate what lives beneath the dwindling sea ice and glacier tongues of polar regions, species and habitat characteristics new to science are discovered wherever we look into the deep.
This is where the combination of two technologies come into their own: unmanned submarines or remotely operated vehicles and eDNA sampling. We will showcase how it works in the coastal zone to students of Lipson Co-operative Academy during the forthcoming Plymouth Ocean Science Voyage on board the tall ship Pelican of London in September 2026. Watch this space.
References
[1] United Nations (no date) Territorial Sea and Contiguous Zone. United Nations Convention on the Law of the Sea – Part II. https://www.un.org/Depts/los/convention_agreements/texts/unclos/unclos_e.pdf.
[2] De Juan S, Ospina-Alvarez A, Hinz H, et al. 2023. The Continental shelf seascape: a network of species and habitats. Biodiversity and Conservation 32, 1271-1290. https://doi.org/10.1007/s10531-023-02552-8.
[3] Skakala J, Awty-Carroll K, Menon PP, et al. 2023. Future digital twins: emulating a highly complex marine biogeochemical model with machine learning to predict hypoxia. Frontiers in Marine Science Sec. Marine Biogeochemistry 10. https://doi.org/10.3389/fmars.2023.1058837.
[4] Isaksson N, Scott BE, Hunt GL, et al. 2025. A paradigm for understanding whole ecosystem effects of offshore wind farms in shelf seas. ICES Journal of Marine Science, 82 (3). https://doi.org/10.1093/icesjms/fsad194.
[5] Ramirez-Llodra E. 2020. Deep-sea ecosystems: biodiversity and anthropogenic impacts. In The law of the seabed (pp. 36-60). Brill Nijhoff. https://www.jstor.org/content/pdf/oa_chapter_edited/10.1163/j.ctv2gjwmv4.9.pdf?acceptTC=true&coverpage=false&addFooter=false.
[6] Paulus E. 2021. Shedding light on deep-sea biodiversity – a highly vulnerable habitat in the face of anthropogenic change. Frontiers in Marine Science Sec. Global Change and the Future Ocean, 8. https://doi.org/10.3389/fmars.2021.667048.
[7] UNEP. 2021. Alboran Sea: Ecology and human activities. United Nations Environment Programme Mediterranean Action Plan. UNEP(DEPI)/MED WG.408/Inf.18. https://rac-spa.org/nfp12/documents/information/wg.408_inf18_eng.pdf ↩︎
[8] Katsanevakis S et al. 2014. Invading the Mediterranean Sea: biodiversity patterns shaped by human activities. https://doi.org/10.3389/fmars.2014.00032 ↩︎
[9] Maglio A et al. 2025. ACCOBAMS Mediterranean Technical Assessment on Anthropogenic Underwater Noise. Ecological Objective 11 – Energy including underwater noise. 9th Meeting of the Parties of Accobams, Limassol, Republic of Cyprus. https://doi.org/10.70978/FGOD6973. ↩︎
[10] Figure CCP4 FAQ4.1.1 in Ali E et al. 2022. Cross-Chapter Paper 4: Mediterranean Region. In: Climate Change 2022: Impacts, Adaptation and Vulnerability. Contribution of Working Group II to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change [Pörtner H-O et al. (eds.)]. Cambridge University Press, Cambridge, UK and New York, NY, USA, pp. 2233–2272, doi:10.1017/9781009325844.021. ↩︎
[11] Hutchins R. 2025. EU Court: Marine Protected Areas must be shielded from trawling. Oceanographic News on 22/05/2025. https://oceanographicmagazine.com/news/eu-court-marine-protected-areas-must-be-shielded-from-trawling/ ↩︎
[12] SOEST. 2016. Manganese nodules as breeding ground for deep-sea octopods. University of Hawaii at Manoa. Press Release December 2016. https://www.soest.hawaii.edu/soestwp/announce/press-releases/manganese-nodules-as-breeding-ground-for-deep-sea-octopods-2/
[13] Tsholofelo P. 2025. How Offshore Wind Farms Affect Marine Life (Benefits & Challenges). The Pulse by Ocean Portal. https://oceaninfo.com/ocean/conservation/offshore-wind-farms-marine-impact/
[14] Seabed 2030. Official Website. https://seabed2030.org
Challenging Habitat 