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News article11 January 2023Directorate-General for Environment

Global horizon scan reveals the 15 issues that are expected to impact marine and coastal biodiversity conservation in the near future

Issue 592: Marine and coastal habitats are experiencing unprecedented environmental change – with some of the drivers of change due to overlooked and emerging issues in the areas of resource-exploitation, new-technology and ecosystem issues.

Coastal landscape depicting sandy shore, water, and cloudy skies.
Photo by Jan Holm, Shutterstock

This study assembled a panel of 30 experts – including scientists, policymakers and conservation practitioners –to identify issues that are likely to significantly impact the functioning, and conservation, of marine and coastal ecosystems in the next 510 years.

The well-known drivers of marine and coastal changes are overexploitation, climate change, and pollution – but there are also emerging issues that are poorly understood, with potential to impact marine and coastal ecosystems. This study identifies and raises awareness of these little-known issues to catalyse further research – enabling identification of any resultant positive or negative impacts. The researchers highlight that it is especially important to identify these issues during the UN Decade of Ocean Science for Sustainable Development (2021–2030).

Informing the wider public and policymakers of potential threats to marine and coastal biodiversity benefits our oceans and society by instigating a precautionary approach and promoting conservation management actions designed to prevent or mitigate possible risks. Some of the emerging issues identified in this study could have unintended negative impacts, if not dealt with appropriately in time.

Thirty marine and conservation experts (from 11 countries, across six continents), initially submitted a total of 75 issues likely to have a significant positive or negative impact on marine biodiversity in the next 5–10 years. The panel consulted their own networks to identify issues, and avoid any bias – in total around 680 participants were involved in identifying issues. Each expert then used a scoring process, confidentially to rank the issues. The top-ranked 32 issues were discussed afterwards in an online discussion workshop, and experts re-scored each topic – thereby producing the final 15 highest-rated issues. Finally, the core researchers discussed the ranked issues to ensure they met the criteria around novelty and each issue’s importance for and probable impact on, marine and coastal biodiversity within 5–10 years.

The researchers then grouped the final 15 issues into three categories, as below, not based on rank-score order:

1.Ecosystem impacts:

  • Wildfire impacts on coastal and marine ecosystems from released aerosols, particles and materials containing nutrients – such as nitrogen and phosphorus – transported to oceans via wind and rain.
  • Coastal darkening of marine waters due tobrowning from organic carbon/iron/particles entering the ocean, re-suspended sediments due to dredging and other fishing activities, and algal blooms from eutrophication.
  • Effects of altered nutritional content of fish resulting from climate change – the production of essential fatty acids (EFAs) in phytoplankton is impacted by effects of ocean warming, reducing the nutrient quality of fish. EFAs are vital for maintaining human and animal health, and fish are the primary source of EFAs for many.
  • Increased toxicity of metal pollution due to ocean acidification in more acidic oceans there is higher uptake of toxic metals by wild-caught and farmed bivalves such as oysters and mussels. This could also affect human health.
  • Equatorial marine communities are experiencing a dip in numbers and variety of species due to climate migration towards the poles.

2. Resource exploitation:

  • The untapped potential of marine collagens and their impacts on marine ecosystems. Collagens, increasingly used in cosmetics and pharmaceuticals, were originally taken from bovine and porcine sources. New sources of collagens could be taken from farmed sponges and jellyfish, while offcuts from the fishing industry could offer a sustainable approach to collagen production. The researchers highlight the overfishing of sponges, as well as the use of sharks and other cartilaginous fish – as these species are already under pressure.
  • Impacts of the expanding trade for fish swim bladders (a valuable Asian food delicacy)on target and non-target species, leading to species numbers plummeting to near extinction.
  • Impacts of deep-water fishing on the biological ocean carbon pump (theprocess through which the ocean takes up excess carbon). Approximately 10 billion tons of fish, such as lanternfishes (Myctophidae), currently sequester carbon to the ocean floor, and these fish may soon be exploited by the fishing industry for aquaculture feed. The vertical migration of lantern fish transports carbon from the surface waters, where they feed, to the deep ocean waters (via death or excretion).
  • Extraction of lithium from deep-sea brine pools in response to the demand for batteries. If this occurs on a large scale, it could harm deep-sea brine ecosystems which may have high levels of endemism (when a species is found in a single geographic location) and/or genetically distinct diversity (potentially offering new genetic resources to medicine).

3. New technologies:

  • Colocation of marine activities or multipurpose projects – for example, siting offshore windfarms in conjunction with aquaculture developments optimising spatial planning. Such activities and projects can create technical, economic and environmental challenges that could be mitigated by siting them in the same location. To prevent these multifunctional structures negatively impacting on the environment rather than benefiting it, environmental and ecosystem assessment, management and regulatory frameworks should be established.
  • Floating marine cities – a design concept which aims to overcome urban challenges, such as lack of housing or climate change.
  • Trace-element contamination in coastal sediments resulting from the global transition to green technologies – for example increased use of electric-vehicle battery elements (e.g. nickel and cobalt).
  • Newunderwater-tracking systems to study non-surfacing marine animals (such as ‘underwater backscatter localisation’ – a battery-free technology based on acoustic recordings). These systems could offer improved information about the movements and distribution of marine animals, but their potential impacts on species behaviour are as yet unknown.
  • Soft robotics for marine research – this technology could be used to collect data from deeper waters, currently not easily accessible, and facilitate the safe collection of species. However, the devices used may add pollutants to deep sea regions, or be inadvertently swallowed by predatory species.
  • Long-term effects of newbiodegradable materials (e.g. biodegradable polymers) in the marine environment. The impacts of these materials remain largely unknown.

The researchers suggest that the early identification and prioritisation of these issues will enable appropriate management, mitigation and support to those addressing the significant challenges facing marine and coastal ecosystems


Herbert-Read, J. E., Thornton, A., Amon, D. J., Birchenough, S. N. R., Côté, I. M., Dias, M. P., Godley, B. J., Keith, S. A., McKinley, E., Peck, L. S., Calado, R., Defeo, O., Degraer, S., Johnston, E. L., Kaartokallio, H., Macreadie, P. I., Metaxas, A., Muthumbi, A. W. N., Obura, D. O., Paterson, D. M., Piola, A. R., Richardson, A. J., Schloss, I. R., Snelgrove, P. V. R., Stewart, B. D., Thompson, P. M., Watson, G. J., Worthington, T. A., Yasuhara, M. and Sutherland, W. J. (2022). A global horizon scan of issues impacting marine and Coastal Biodiversity Conservation. Nature Ecology & Evolution, 6(9): 1262–1270.

To cite this article/service:

Science for Environment Policy”: European Commission DG Environment News Alert Service, edited by the Science Communication Unit, The University of the West of England, Bristol.

Notes on content:

The contents and views included in Science for Environment Policy are based on independent, peer reviewed research and do not necessarily reflect the position of the European Commission. Please note that this article is a summary of only one study. Other studies may come to other conclusions.


Publication date
11 January 2023
Directorate-General for Environment

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