Ewan Garvey, one of Project Seagrass’ Interns for the 2025-26 academic year, explores how seagrass can provide protection for coastal communities. As the seasons transition from autumn into winter, storms often become a pressing concern for coastal communities. In recent years, the growing impacts of climate change have become increasingly
Jasper Brown, one of Project Seagrass’ Interns for the 2025-26 academic year and 3rd Year Student in BSc Zoology with Marine Zoology at Bangor University, explores the need for both active and passive restoration to secure a future for our important seagrass habitats. Marine ecosystems worldwide are under threat. Rising
In an article for Halloween, Grace Cutler, one of Project Seagrass’ Interns for the 2025-26 academic year, explores the frightening reality of continued seagrass loss as a result of anthropogenic activity and how this in turn threatens seagrass’ role in supporting people and planet. Werewolves are struck down by silver
Seaweed farming is a rapidly expanding global industry. As a food resource, it has high nutritional value and doesn’t need fertilisers to grow. Seaweed provides valuable habitats for marine life, takes up carbon and absorbs nutrients, plus it helps protect our coastlines from erosion. Usually, seaweeds grow on hard, rocky surfaces. Yet, to
Ewan Garvey, one of Project Seagrass’ Interns for the 2025-26 academic year, explores how seagrass can provide protection for coastal communities. As the seasons transition from autumn into winter, storms often become a pressing concern for coastal communities. In recent years, the growing impacts of climate change have become increasingly clear: extreme weather events once considered “once-in-a-decade” now seem to strike far more frequently. In response, governments and communities are looking for protective solutions, investing heavily in sea defence systems, ranging from sandbags to seawalls. But what if nature has already developed a solution? Enter seagrass. Seagrass’s unique characteristics make it a powerful ally in protecting coastlines. Unlike concrete walls or other flood defence systems, seagrass meadows work with natural processes to reduce erosion and flooding, while also creating vital habitat for marine life. How Seagrass Protects Our Shores Root FixationMuch like how trees stabilise the soil in forests, seagrass root systems anchor sand and mud in place, reducing sediments from being washed away during storms. This helps to maintain the structure of beaches, providing more stable coastal habitats. Dissipation of Wave EnergyWhen waves pass over seagrass meadows, the blades create friction. This slows the water, disperses energy, and reduces the force that reaches the shoreline. This means water travels up the beach less and can lessen flooding events. Challenges Hard-engineered coastal defences such as rock armour can cost upwards of £1 million for just a 35-metre section. Seagrass restoration is also expensive, and to date has been largely funded through philanthropic and government funding mechanisms. Seagrass restoration is not without challenges; newly planted seeds are vulnerable to being washed away or buried by shifting sediment before they can properly establish. Seagrass also requires good water quality; too much pollution can prevent seedlings from developing. In many areas, improving river and coastal water quality must go hand in hand with restoration for projects to succeed. A Blended Solution Is seagrass the silver bullet for coastal protection? Not entirely. By blending natural and engineered approaches, we can create more sustainable, resilient coastlines—ones that not only protect us from storms but also support thriving marine ecosystems. Combining engineered solutions such as breakwaters or seawalls with seagrass meadows could reduce wave energy and sediment loss, which would lower the stress on the artificial defences. This could result in cheaper, smaller sea defence structures, reducing both environmental impact and cost. References and Extra Research “Seagrass as a nature-based solution for coastal protection” by Forrester, Leonardi, Cooper & Kumar (2024) Infantes et al. (2022) — Seagrass roots strongly reduce cliff erosion rates in sandy sediments Donatelli et al. (2018) — “Seagrass Impact on Sediment Exchange Between Tidal Flats and Salt Marsh, and The Sediment Budget of Shallow Bays” Bricheno, L. M., et al. “Climate change impacts on storms and waves relevant to the UK and Ireland.” MCCIP Science Review 2025 (2025).
Jasper Brown, one of Project Seagrass’ Interns for the 2025-26 academic year and 3rd Year Student in BSc Zoology with Marine Zoology at Bangor University, explores the need for both active and passive restoration to secure a future for our important seagrass habitats. Marine ecosystems worldwide are under threat. Rising temperatures, ocean acidification, and water pollution are just a few of the key drivers in the decreasing quality of our marine ecosystems. Researchers have found that many aquatic species are shifting poleward at an average rate of 70 kilometres every decade (Melbourne-Thomas et al., 2021) – a vast response to changing conditions. Species such as the American Lobster, Cushion Star, and Humboldt Squid have nearly doubled their latitude range, showing the clear extent of this poleward shift in marine species (Pinsky et al., 2020). Why are they moving? One crucial reason is habitat loss. Seagrass meadows, coral reefs, and kelp forests are disappearing worldwide, reducing opportunities for biodiversity and removing essential nursery habitats for marine life. The solution is clear: we must conserve and restore. Across the globe, charities and organisations are embracing active restoration – direct interventions to rebuild habitats. The work consists of planting seagrass, reforesting mangroves, and coral Gardening. All of which provide crucial environmental benefits: large carbon sinks, coastal protection, and providing nursery habitats. Seagrass planting involves transplanting seeds and rhizomes near existing meadows (do Amaral Camara Lima et al., 2023). Coral gardening uses nurseries to grow coral fragments, which are later transplanted to reefs that support approximately 25% of all marine species (Rinkevich, 2014; Gallagher, 2025; Pacific Coastal and Marine Science Center, 2022). Mangrove reforestation involves planting seedlings along suitable coastlines (Zahra Farshid et al., 2022; Bimrah et al., 2022). These methods are being implemented worldwide, from the Persian Gulf in western Asia to the Firth of Forth in Scotland. Yet, challenges persist. Active restoration projects are costly, often relying on charitable donations and grants (Paling et al., 2009). Despite these hurdles, active restoration works, a recent review by Danovaro (2025), found an average success rate of 64% across 764 projects. Is active restoration enough? However, success depends on environmental conditions; water clarity, for example, is critical for seagrass survival due to photosynthesis requiring sufficient light. Declining clarity, driven by pollution, bottom trawling, and dredging, increases turbidity, which limits restoration efforts (Paling et al., 2009). This is where passive restoration comes in Passive strategies focus on removing environmental pressures and creating conditions for ecosystems to heal naturally. Examples include implementing policies to regulate fertilizer use and reduce nutrient runoff, as well as enforcing Marine Protected Areas (MPAs). These acts will reduce eutrophication in our waterways and lead to a more stable marine environment, leading to the eventual reduction in coral bleaching and seagrass meadow reduction. MPAs have been shown to restore ecosystem functions such as predation (Cheng et al., 2019), highlighting their critical role in maintaining biodiversity. Conclusion While MPAs are just one example, they perfectly highlight the value of passive restoration in its entirety. The greatest benefits come from integrating passive and active approaches. By enforcing regulations and establishing strict no-trawl zones, we can reduce nutrient loads and sedimentation. Through these efforts, our marine ecosystems will one day thrive again, meaning we get to see the animals and plants we so dearly care about. References Bimrah, K., Dasgupta, R., Hashimoto, S., Saizen, I., & Dhyani, S. (2022). Ecosystem Services of Mangroves: A Systematic Review and Synthesis of Contemporary Scientific Literature. Sustainability, 14(19), 12051. https://doi.org/10.3390/su141912051 Bulmer, R. H., Townsend, M., Drylie, T., & Lohrer, A. M. (2018). Elevated Turbidity and the Nutrient Removal Capacity of Seagrass. Frontiers in Marine Science, 5. https://doi.org/10.3389/fmars.2018.00462 Cheng, B. S., Altieri, A. H., Torchin, M. E., & Ruiz, G. M. (2019). Can marine reserves restore lost ecosystem functioning? A global synthesis. Ecology, 100(4), e02617. https://doi.org/10.1002/ecy.2617 Danovaro, R., Aronson, J., Bianchelli, S., Boström, C., Chen, W., Cimino, R., Corinaldesi, C., Cortina-Segarra, J., D’Ambrosio, P., Gambi, C., Garrabou, J., Giorgetti, A., Grehan, A., Hannachi, A., Mangialajo, L., Morato, T., Orfanidis, S., Papadopoulou, N., Ramirez-Llodra, E., & Smith, C. J. (2025). Assessing the success of marine ecosystem restoration using meta-analysis. Nature Communications, 16(1). https://doi.org/10.1038/s41467-025-57254-2 do Amaral Camara Lima, M., Bergamo, T. F., Ward, R. D., & Joyce, C. B. (2023). A Review of Seagrass Ecosystem services: Providing nature-based Solutions for a Changing World. Hydrobiologia, 850(12-13), 2655–2670. https://doi.org/10.1007/s10750-023-05244-0 Gallagher, M. (2025, August 24). What Ecosystem Services Do Coral Reefs Provide? – Green Packs. GreenPacks. https://greenpacks.org/what-ecosystem-services-do-coral-reefs-provide/ Melbourne-Thomas, J., Audzijonyte, A., Brasier, M. J., Cresswell, K. A., Fogarty, H. E., Haward, M., Hobday, A. J., Hunt, H. L., Ling, S. D., McCormack, P. C., Mustonen, T., Mustonen, K., Nye, J. A., Oellermann, M., Trebilco, R., van Putten, I., Villanueva, C., Watson, R. A., & Pecl, G. T. (2021). Poleward bound: adapting to climate-driven species redistribution. Reviews in Fish Biology and Fisheries. https://doi.org/10.1007/s11160-021-09641-3 Pacific Coastal and Marine Science Center. (2022, June 27). Role of Reefs in Coastal Protection | U.S. Geological Survey. Www.usgs.gov. https://www.usgs.gov/centers/pcmsc/science/role-reefs-coastal-protection Paling, Fonseca, M., Katwijk, M., & Keulen, van. (2009). Seagrass restoration. In Coastal wetlands: an integrated ecosystems approach. (pp. 687–713). Rinkevich, B. (2014). Rebuilding coral reefs: does active reef restoration lead to sustainable reefs? Current Opinion in Environmental Sustainability, 7, 28–36. https://doi.org/10.1016/j.cosust.2013.11.018 Zahra Farshid, Reshad Moradi Balef, Tuba Zendehboudi, Dehghan, N., Mohajer, F., Siavash Kalbi, Hashemi, A., Afshar, A., Tabandeh Heidari Bafghi, Hanieh Baneshi, & Amin Tamadon. (2022). Reforestation of grey mangroves (Avicennia marina) along the northern coasts of the Persian Gulf. Wetlands Ecology and Management, 31(1), 115–128. https://doi.org/10.1007/s11273-022-09904-1
In an article for Halloween, Grace Cutler, one of Project Seagrass’ Interns for the 2025-26 academic year, explores the frightening reality of continued seagrass loss as a result of anthropogenic activity and how this in turn threatens seagrass’ role in supporting people and planet. Werewolves are struck down by silver bullets, vampires are defeated with wooden stakes; the environment is protected by seagrass. While it may not be as dramatic, the narrative that aligns seagrass as the ultimate solution to combating the environmental crisis is popular. As someone studying this remarkable habitat, it’s easy to see why. The only marine flowering plant in the world, seagrass offers numerous ecological benefits, supporting both our planet and humanity. Despite this, we risk ignoring the crux of the issue by relying on these green solutions. We keep polluting. It is because we continue to pollute our environment, be it through greenhouse gases, plastic pollution, or general waste production, that the very things that help to prevent the environmental crisis, are dying. A Natural Water Filter? While seagrass may not clean water bodies, it increases particle deposition rates by slowing the speed of waves and allowing more time for particles to sink to the ocean floor. Particles can then become trapped in the seagrass meadow and are prevented from ending up elsewhere in waterways. This process has been shown to capture excess nutrients, waste products, and even pathogens. A study conducted in the greater Seattle Metropolitan Area showed that mussels placed in seagrass habitats had 65% less relative abundance of some pathogens when compared to mussels placed in habitats without seagrass. Yet, the most apparent threat to seagrass, identified by UK researchers, is water quality. Like most plant species, seagrass can function in polluted water quality up to a point or ‘threshold value’. Similar to how humans can eat a certain number of toffee apples until it becomes too much and we get a sugar crash. Once this threshold is exceeded, seagrass will decline and, in some severe instances, disappear from the environment entirely. One such instance can be seen in the Chinese province Hainan, where researchers found that a dissolved inorganic nitrogen concentration of 8μM or above will cause seagrass meadows to disappear. This is because an excess of nutrients in water bodies, like nitrogen, stimulates the production of algae which blooms on the surface of the water and prevents sunlight from reaching seagrass beds. Additionally, some nutrients like ammonium and sulphides can have direct negative effects on seagrass growth. Fortifying our Coastlines Imagine a castle that is under attack. If it is strong and maintained, the castle will be better at defending itself against intruders. However, the next time it is under attack, there are holes and weak points left in it from the previous battle. Over time, this castle falls into disrepair and becomes a ruin, leaving it unable to protect its inhabitants. Seagrass is similar. Its inhabitants are our coastlines. Coastlines today are facing threats on all fronts. Sea level rise, extreme storms, and erosion are just some of the problems they experience. With that said, some have considered using seagrass as a way of minimising the impact of storms causing erosion in these areas. Through their matted root systems, called rhizomes, seagrass meadows have been shown to improve the stability of sediments and reduce wave energy before it reaches the shore in some hydrodynamic systems. Yet, seagrass is also harmed by these storms. Meadows that are struck by intense physical disturbances can be uprooted or die back, initiating a positive feedback loop where meadows in decline are more vulnerable to disturbances. This means when the next storm hits, seagrass not only will be more susceptible to decline, but they are also less able to protect our coasts. What About Carbon? Carbon storage is a phrase often thrown around. It may be the key reason why people are interested in seagrass as an answer to climate change. With anxiety surrounding our warming planet on the rise, this isn’t unprecedented. However, seagrass may not be quite the antidote we think it is. Recent evidence has shown that following disturbances, carbon stored in the soil of meadows may be re-released into their environment as carbon dioxide. Such disturbances can range from direct physical effects, such as dredging and construction work, or indirect global threats stimulated by climate change. A 2011 marine heat wave struck the West-coast of Australia, causing the reported loss of over 1000 km2 of seagrass in Shark Bay. Another instance of mass seagrass loss occurred in the Gulf of Mexico, where two seagrass species (Halodule wrightii and Syringodium filiform) disappeared following sea level rise in 2014. Without seagrass, the carbon stored in these soils is easily remineralised and released back into the environment. What’s Next? Thankfully, the main factor contributing to seagrass decline appears to be anthropogenic impacts such as dredging, overfishing, and agricultural runoff. This means that with changes in how we do things, we can stop the death of seagrass. However, this means seagrass mustn’t be painted as a plaster to patch up the pollution of the planet. To help seagrass, we must reduce pollution, reduce nutrient runoff, protect seagrass so it can protect us! References Ranking the risk of CO2 emissions from seagrass soil carbon stocks under global change threats Extreme climate events lower resilience of foundation seagrass at edge of biogeographical range Too hot to handle: Unprecedented seagrass death driven by marine heatwave in a World Heritage Area Rapid sea level rise causes loss of seagrass meadows Seagrass ecosystems as green urban infrastructure to mediate human pathogens in seafood Toxic effects of increased sediment nutrient and organic matter loading on the seagrass Zostera noltii Losses and recovery of organic carbon from a seagrass ecosystem following disturbance Continual migration of patches within a Massachusetts seagrass meadow limits carbon accretion and storage Mediterranean seagrasses provide essential coastal protection under climate change
Seaweed farming is a rapidly expanding global industry. As a food resource, it has high nutritional value and doesn’t need fertilisers to grow. Seaweed provides valuable habitats for marine life, takes up carbon and absorbs nutrients, plus it helps protect our coastlines from erosion. Usually, seaweeds grow on hard, rocky surfaces. Yet, to farm seaweed, potential areas need to be easily accessible and relatively sheltered. This is where seaweed can grow with limited risk of being dislodged by waves. Seaweed farms in Asia, in countries like China and Indonesia, are responsible for more than 95% of global seaweed production. Seaweed farms, particularly those in Southeast Asia, are commonly in the very same environments where seagrass meadows thrive. Competition for resources ensues. Evidence shows that tropical seaweed farms, when placed in or on top of tropical seagrass meadows leads to a decline in the growth and productivity of seagrass. There is also evidence that seaweeds outcompete seagrasses in cooler waters, especially when nutrients in the water are very high. Despite negative interactions, such as shading, between seaweed and seagrass, some scientists now advocate for a global expansion of seaweed farming in areas where seagrass grows. This call, comes at a time when seagrass global initiatives are trying to stem seagrass loss. Efforts are underway to expand these habitats to their once extensive range to help fight climate change and biodiversity loss. Seagrass meadows are a crucial store of carbon, providing habitats for a wide array of animals. Why farm seaweed on top of seagrass? The reason that some scientists are advocating for farming seaweed in seagrass is that their research claims that the presence of seagrass reduces disease causing bacterial pathogens by 75%. A major win for a relatively low tech industry where seaweed disease outbreaks hinder production. These scientists are not the only ones advocating for seaweed production at scale. Global conservation charities, like World Wildlife Fund and The Nature Conservancy, as well as the Earthshot prize launched by Prince William all support seaweed cultivation programmes in areas likely to contain abundant seagrass. However, together with other scientists, we have argued in an academic response in the journal PNAS that their claim is premature. We are concerned that, without appropriate management, these seaweed programmes threaten marine biodiversity and the benefits that humans get from the ocean. Despite historic and globally widespread seaweed cultivation, effects on seagrass have mostly been ignored. Where studies exist, effects have been negative for seagrass, its ability to capture carbon, and the diverse animals that call it home. Entanglement of migratory animals, such as turtles and dugong with seaweed also needs wider consideration. This is especially the case given new legal frameworks to protect their habitat, and there is ongoing concern for these species being killed by seaweed farmers. The equity of coastal fishing grounds also comes into question, as communities that use seagrass for fishing are most likely to lose access. Conservation charities advocate for tropical seaweed farms for good reason. This is to improve community resilience in the face of degrading coral reefs and overfishing. While projects mostly have the best intentions, they often don’t consider cascading unintended consequences, nor the equity of the whole community. In reality, seaweed farm placement is effectively akin to ocean grabbing (the act of dispossession or appropriation of marine resources or spaces) with farmers winning on a “first come, first serve” basis, despite not owning the seabed. Some seagrass meadows in Zanzibar, Tanzania, have recovered since seaweed farms have been removed. GoogleEarth Sustainable standards If seaweed farming is to be expanded, standards for sustainability must be upheld and strengthened. In 2017, a sustainable seaweed standard was launched by the Aquaculture and Marine Stewardship Councils. But few tropical seaweed farms meet the criteria outlined in this standard due to known consequences that affect seagrass (rightly defined in the standard as vulnerable marine habitats) and likely negative effects on endangered species, like dugong, that frequent seagrass habitats. Seaweed cultivation strategies have mixed evidence for long-term success. In Tanzania, many farmers have abandoned the industry due to low monetary rewards compared to the investments they put in, and some evidence suggests that the activity reduces income and health, particularly for women. Where seaweed cultivation has been implemented to reduce fishing pressure, it has instead increased (and often just displaced) fishing activity. Given the rapidly increasing threats faced by tropical marine habitats despite the role they play in climate resilience, understanding trade-offs prior to large scale expansion of seaweed farming is a priority. To reduce further any negative effects, international programmes and research advocating for large-scale seaweed farms need to align more readily with the seaweed standard. More information: This article was published in The Conversation Jones. et al, Risks of habitat loss from seaweed cultivation within seagrass, PNAS (2025). https://doi.org/10.1073/pnas.242697112 Seaweed farms are often placed on top of seagrass meadows. Niels Boere/flickr A women prepares seaweed ropes for deployment in the Wakatobi, Indonesia. Benjamin Jones/Project Seagrass
