Why coastal ecosystems are disappearing at alarming rates
The United Kingdom has witnessed a staggering decline in its coastal habitats over the past half‑century. Research indicates that more than 85 % of aquatic and marine vegetation—including saltmarsh, seagrass and kelp—has vanished, undermining biodiversity, water quality and the natural capital that supports fisheries, tourism and flood protection. This loss is driven by urbanisation, hard engineering defences such as seawalls, nutrient runoff and the increasing frequency of storm overflows. In response, the University of Portsmouth has launched an innovative initiative that seeks to reverse these trends by deploying specially engineered floating wetlands in marine settings.
How the floating wetlands project works
Led by Dr Ian Hendy from the Institute of Marine Sciences, the project partners with Southern Water to install a series of floating pontoons designed to support saltmarsh vegetation. Unlike traditional restoration efforts that rely on re‑planting directly onto degraded shorelines, these pontoons create a buoyant platform that can be positioned in areas where hard infrastructure has eliminated natural habitat. The pontoons are seeded with a diverse mix of saltmarsh plants, and for the first time in a UK marine context, researchers are trialling the cultivation of marine species on a floating system—a technique that has only been tested six times previously worldwide.
The floating wetlands are anchored at the South Coast Wake Park in Portsmouth, providing a controlled, before‑and‑after monitoring environment. Scientists will measure changes in water quality, biodiversity and ecosystem resilience over an extended period, using environmental DNA (eDNA) sequencing to track shifts from microbial communities up to fish and invertebrates. This approach not only reveals which organisms colonise the new habitat but also helps identify the origins of bacteriological communities—whether human, avian or livestock—information that is vital for Southern Water’s shellfish protection and bathing water quality programmes.
Environmental benefits of floating saltmarshes
By mimicking the functions of natural saltmarshes, the floating wetlands deliver multiple ecosystem services:
- Water quality improvement: The vegetation absorbs excess nutrients such as nitrogen and phosphorus, reducing the risk of algal blooms and mitigating the impact of storm‑overflow pollutants.
- Biodiversity net gain: The complex root structures and sheltered water columns provide refuge for fish, crustaceans and invertebrates, while also attracting terrestrial pollinators that use the emergent vegetation for foraging.
- Carbon sequestration: Saltmarsh plants are efficient at capturing atmospheric CO₂ and storing it in their biomass and the underlying sediment, contributing to climate‑change mitigation.
- Natural capital enhancement: Restored habitats increase the aesthetic and recreational value of coastal zones, supporting local economies that rely on tourism, angling and wildlife watching.
These benefits align with the United Nations Sustainable Development Goals, particularly those concerning clean water (SDG 6), climate action (SDG 13) and life below water (SDG 14). Moreover, the UK’s coastal ecosystem services are estimated to be worth £211 billion to the national economy, underscoring the economic imperative of habitat restoration.
Scalability and future applications
One of the project’s core strengths lies in its scalability. The modular nature of the floating pontoons means that units can be added, removed or reconfigured according to site‑specific needs. Joff Edevane, Environment & Water Quality Lead for Southern Water, notes that if the pilot proves successful, the technology could be rolled out across the UK in both marine and freshwater environments—including areas targeted by the Three Harbours initiative in the Solent region.
Future research will explore how floating wetlands can be integrated into protected areas, urban waterfronts and even offshore renewable energy installations, where they could serve as ecological buffers around turbine foundations. The project also aims to develop best‑practice guidelines for stakeholders ranging from local councils to private developers, ensuring that nature‑based solutions become a standard component of coastal management strategies.
How you can get involved
Whether you are a student, researcher, practitioner or simply a concerned citizen, there are several ways to engage with the floating wetlands initiative:
- Stay informed: Follow the University of Portsmouth’s news portal for updates on monitoring results, publications and upcoming webinars.
- Participate in citizen science: Volunteer opportunities are periodically announced for water‑sampling, vegetation surveys and eDNA collection events.
- Explore study options: The University offers undergraduate and postgraduate programmes in Marine Biology, Environmental Science and Coastal Engineering that include hands‑on work with the floating wetlands project.
- Collaborate: Businesses, NGOs and governmental bodies interested in piloting similar solutions can contact the Institute of Marine Sciences to discuss partnership models.
- Spread the word: Share this article on social media, leave a comment below with your thoughts, or write to us with any questions you may have.
Conclusion
The floating wetlands project represents a bold step toward reclaiming lost coastal habitats in the face of relentless urban pressure. By combining cutting‑edge engineering with ecological expertise, the University of Portsmouth and Southern Water are demonstrating that nature‑based solutions can be both practical and scalable. As the initiative progresses, the data gathered will not only illuminate the effectiveness of floating saltmarshes but also inform broader strategies for biodiversity net gain, water quality improvement and climate resilience across the UK’s coastline.
If you are inspired by the potential of floating wetlands to revitalise our seas and shores, consider taking one of the actions outlined above. Together, we can help ensure that the UK’s coastal ecosystems continue to provide the ecological, economic and cultural benefits that communities depend on.
Ready to learn more about studying marine sciences at the University of Portsmouth? Explore our undergraduate courses and discover how you can contribute to the next generation of environmental innovators.
Have questions about the floating wetlands project or want to discuss collaboration? Write to us – our team is happy to provide further details.
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