Heat stress from marine heat waves can create a toxic relationship between seagrasses and a hidden ecosystem of bacteria, transforming a previously beneficial co-existence between marine plants and microbes into a harmful one, a University of Sydney and UNSW study has found. Seagrasses are marine flowering plants that act as
As our Fragment Walks from the 2025/26 season come to an end Project Seagrass Intern Anya Lamparelli reflects on this year’s efforts. A seagrass fragment is a precious and vulnerable thing. Torn free by winter storms and strong swells these delicate shoots with intricate root systems still attached wash ashore
A new study of the British Isles’ coastal ecosystems has revealed that nitrogen enrichment is significantly reducing the abundance and variety of marine life. The research, published by scientists at Swansea University and the charity Project Seagrass, warns that increasing nutrient flows are overriding local habitat conditions to restructure and
Residents and visitors to the Isle of Wight can now access information about the Island’s important seagrass habitats thanks to new signage installed through support from Seacology. The signage has been installed by Project Seagrass as part of ongoing efforts to protect and restore seagrass ecosystems within the Solent. The signs
Hannah Harrero and Stephanie Insalaco-Wyner, geographers from Florida, comment on differing methods of monitoring the resilience of seagrass meadows in Florida’s ‘Mosquito Lagoon’, following a number of extreme weather events. Florida’s Indian River Lagoon has been an ecosystem in decline going back to 2011, when harmful algal blooms led to a severe decline in
Heidi McIlvenny, PhD researcher from Queen’s University Belfast, comments on seagrass meadows in Northern Ireland and how seagrass meadows can recover but only if we tackle the pollution at its source. I spent last summer wading through seagrass meadows across Northern Ireland, from the sheltered waters of Strangford Lough to
Between the 17th and 23rd March 2026, members of the Project Seagrass team were on the Isle of Wight carrying out active restoration as part of the The Solent Seascape Project, the first project of its kind in the UK to initiate seascape-scale restoration. As part of The Solent Seascape
New research led by scientists at University of California’s San Diego’s Scripps Institution of Oceanography is shining a spotlight on one of the ocean’s most overlooked habitats: seagrass. Led by Scripps Oceanography Ph.D. candidate Rilee Sanders, the study documented the first successful restoration of open-coast seagrass (common eelgrass). The findings offer
Nursery intern Iestyn Comey details how fishing in seagrass meadows can be great to improve mental health and are vital nursery grounds for key fisheries species. Fishing is a hard thing to explain to someone who has never done it. There is no better feeling than the moment the line
Extreme heat can have a devastating effect on seagrass, but new research from Edith Cowan University (ECU) could shape how these vitally important marine ecosystems are managed and restored. In separate studies carried out on both the west and east coasts of Australia, researchers have investigated how seagrasses stand up
Heat stress from marine heat waves can create a toxic relationship between seagrasses and a hidden ecosystem of bacteria, transforming a previously beneficial co-existence between marine plants and microbes into a harmful one, a University of Sydney and UNSW study has found. Seagrasses are marine flowering plants that act as fish nurseries, purify water and are crucial in coastal carbon storage. Their decline is often missed until it’s too late. The role soil microbes play in land plant health and climate resilience is well known. But for marine plants like seagrass, this science has largely been overlooked. “It’s worth paying attention to what happens in seagrass habitats as marine heat waves become more common. That information could be invaluable for conservation efforts,” said lead researcher Dr. Renske Jongen, from the School of Life and Environmental Sciences. In an underwater gardening experiment, biologists found a diverse bacterial ecosystem in the soil and around seagrass roots. The bacterial ecosystem was in a delicate balance, controlling the chemistry of the soil and seagrass health. Under increased water temperature, tiny bacteria living in the sediment among seagrass roots can reduce seagrass tolerance to climate change, stunting its growth and its ability to cope with heat stress. Higher temperatures favor bacterial species known to produce hydrogen sulfide, a compound toxic to seagrass, which may stunt seagrass growth. Plants previously exposed to warmer conditions suffer more from those changes in microbes. The researchers found seagrass growing in sediments from warm areas produces 34% less biomass when the natural sediment microbes weren’t disturbed. The findings show how bacterial communities are a hidden factor in recovering and restoring seagrass. “Just as microalgal symbionts (tiny organisms that rely on sunlight as energy) are key to the health of coral reefs, bacterial symbionts nestled at the roots and sediment of seagrasses can influence whether seagrass survives or declines,” said Dr. Jongen. “Even though seagrasses may look okay at first glance, what we’ve found below ground under increased temperature tells a different story.” Just as heat waves have hit terrestrial plants, marine heat waves have thinned out once lush and widespread seagrass meadows along the Australian coast. They are mainly found in shallow coastal waters and estuaries from tropical Queensland all the way down to the cool, temperate waters of Tasmania. Microbial communities also shape marine plants’ responses to environmental stress. Heat stress isn’t only about hot water. “Increased water temperatures dramatically change the ecosystem of microbes living among the seagrass roots and how microbes co-exist,” said senior author Associate Professor Ziggy Marzinelli from the University of Sydney. “Under heat stress, the microbial communities around seagrass roots shift in ways that can harm rather than help the plant.” How decades of industrial history created a real-world climate experiment In Myuna Bay in Lake Macquarie, history has created the perfect conditions for the research team to answer the question—”what would happen to seagrasses and microbes if water temperatures increased as projected by climate change models?” Since 1984, Eraring Power Station has continually fed a plume of warm estuarine water into the lake. This has made some of the lake waters up to three degrees warmer than ambient temperature for nearly four decades, mimicking both marine heat waves and what future oceans could be like along the Eastern Australia coast by 2090. “This has inadvertently created realistic conditions for the ultimate ‘gardening experiment’—for us to test how seagrass and below ground microbe health is shaped by exposure to higher-than-normal ocean temperatures,” said Dr. Jongen. “Locals are aware of the temperature increase in the area. It also has a reputation as a popular fishing spot because the hot water attracts a lot of fish species and everything from sharks to turtles have been seen here.” The research team transplanted Zostera muelleri, a species of sea grass native to coastal areas of Australia, into the lakebed. They also extracted and analyzed DNA to find the type of bacterial communities from the sediment and sediment from the seagrass roots to find how their composition changed at different temperatures. That was when they uncovered the change in bacterial communities and especially the relative increase of bacterial species that suppressed seagrass growth. “Our study highlights the overlooked role of microbes in tipping the balance in marine environments,” said Professor Paul Gribben from the University of New South Wales. “Seagrass restoration should not just focus on selecting species that are more heat tolerant, but also look deeper, below the ground surface—and, if needed, address microbial communities before transplanting or restoring seagrass meadows.” More information: This article is republished from Phys.org Read the research paper here: Ocean warming indirectly affects seagrass performance through effects on sediment microbial communities – Jongen – New Phytologist – Wiley Online Library
As our Fragment Walks from the 2025/26 season come to an end Project Seagrass Intern Anya Lamparelli reflects on this year’s efforts. A seagrass fragment is a precious and vulnerable thing. Torn free by winter storms and strong swells these delicate shoots with intricate root systems still attached wash ashore from subtidal seagrass meadows. If left stranded on the sand they will soon dry out, but on the Isle of Wight they are being given a second chance. Once a month at low tide, volunteers gather at Priory Bay, all eyes trained on the shoreline for a flash of green. Seagrass! Each fragment found is carefully collected and replanted into a growing community meadow. Since the initiative began three years ago 311 volunteers have joined the Project Seagrass team. Collecting 1,104 fragments over 16 fragment walks. 624 fragments have been replanted at Priory Bay, covering an area of 27 m2. Each month the volunteers revisit what they have already planted and monitor how the meadow is establishing, making field observations on what factors might be influencing its growth and survival. The remaining fragments have been replanted at the Seagrass Nursery in South West Wales; they will soon be used to support the team’s wider restoration work in the Solent. Fragment walks unfold under all conditions. Brilliant unbroken sunshine, pink sunsets, and cold grey mornings where the sky and sea blur into one. Yet the turnout remains steady, demonstrating the interest in and growing connection to seagrass meadows in the Solent. Many volunteers bring with them a deep lived knowledge of the coastline. They know how the beach shifts through the seasons, where sediment builds and erodes and when storms have reshaped the coast. This local insight has become an invaluable part of the project, helping guide where and how we replant seagrass. In turn, we can share our knowledge of ecosystem restoration and marine life. Creating a shared partnership where practitioners and locals learn from each other. Project Seagrass are working to restore 3.5 hectares of seagrass on the Isle of Wight as part of the Solent Seascape Project. Fragment walks allow us to trial new restoration methods while connecting with the local community. Thank you to every volunteer who has joined us in the Solent, we look forward to welcoming you back when the fragment walks restart in September 2026.
A new study of the British Isles’ coastal ecosystems has revealed that nitrogen enrichment is significantly reducing the abundance and variety of marine life. The research, published by scientists at Swansea University and the charity Project Seagrass, warns that increasing nutrient flows are overriding local habitat conditions to restructure and deplete coastal biodiversity. While the Planetary Boundaries for nitrogen and phosphorus flows have already been exceeded globally, this study provides a rare, large-scale assessment of how these nutrients impact the fine-scale diversity of our coastlines. Factors causing the pollution include sewage, agricultural waste, and poor land management. The study examined seagrass meadows in 16 different marine environments, including estuaries, lagoons, and islands. These ranged from the Orkneys Islands and the Firth of Forth to the Solent and the Island of Skomer. The findings were stark: higher nitrogen concentrations were consistently associated with a decrease in animal abundance and species richness. Specifically, the researchers found that an increase of nitrogen could correspond to an approximately 90 per cent decrease in the abundance of life per unit of available habitat area. “Eutrophication, the enrichment of water by nutrients, remains one of the most pressing environmental challenges in coastal waters, particularly regarding biodiversity loss,” said the authors. Key findings: Nitrogen as a driver: Nitrogen enrichment emerged as a consistent driver of biodiversity loss across the UK, even when accounting for the physical complexity of the environment; Habitat sensitivity: Coastal and lagoon environments showed the strongest declines under enhanced enrichment. In particular, phosphorus exhibited a devastating negative effect on life within lagoon environments; Site-specific impact: While some moderate enrichment was tolerated in specific estuarine settings, further enrichment in already impacted coastal sites exacerbated the loss of species; and, Beyond physical structure: Surprisingly, the physical traits of the marine vegetation (such as leaf length or biomass) had little influence on diversity compared to the overwhelming impact of local nutrient regimes. Crab in seagrass in Orkney Credit Lewis Jefferies Gastropods in seagrass. Credit Lewis Jefferies The researchers argue that current regional conservation targets may be insufficient. Because the effects of nutrients are “context-dependent,” effective management requires strategies tailored to the specific ecological conditions of a site. They concluded: “Our findings demonstrate that eutrophication alters biodiversity in complex ways. Effective management will require site-specific nutrient reduction and monitoring strategies that reflect local conditions rather than uniform regional targets.” The research was conducted by scientists from Swansea University, and Project Seagrass. The team used standardised sampling and mixed-effects modelling to isolate the drivers of biodiversity across the UK seascape. Read the research in full in Global Ecology and Conservation.
Residents and visitors to the Isle of Wight can now access information about the Island’s important seagrass habitats thanks to new signage installed through support from Seacology. The signage has been installed by Project Seagrass as part of ongoing efforts to protect and restore seagrass ecosystems within the Solent. The signs have been designed to raise awareness of seagrass meadows around the Isle of Wight in addition to highlighting ways that individuals can support these fragile ecosystems including through participation in Fragment Walks and uploading seagrass sightings to citizen science tool SeagrassSpotter. New seagrass signage installed at St Helen’s Duver Members of the Project Seagrass team installed new signage at locations on the Isle of Wight Two signs were installed in Seaview, the location of one of the Island’s extensive Zostera marina meadows and where Project Seagrass, Blue Parameters, and WarrenBoats have recently installed two Advanced Sustainable Mooring Systems (ASMS) to relieve pressure on the Island’s important seagrass habitats. A further sign has been installed at St Helens Duver, Priory Bay, the location of the start of our Fragment Walks and the site of one of our active restoration sites. Further poster versions of the signs will be installed at Ryde and other locations around the Island. Anouska Mendzil, Senior Science Officer at Project Seagrass and Swansea University said “The Isle of Wight is an UNESCO Biosphere Reserve, home to some of the most ecologically important marine and coastal habitats under threat – seagrass meadows. Across the Isle of Wight, new information signs now share the story of seagrass restoration and conservation, an effort led by Project Seagrass and the collective power of local community action, to contribute and enhance ecosystem recovery.” Seagrass signage installed at Seaview slipway Signage installed on the Southern Water building at St Helen’s Project Seagrass is grateful for the generous support from Seacology for making the creation and installation of these seagrass signs possible. Project Seagrass is also thankful to our stakeholders for their continued support and permission to install the signage.
Hannah Harrero and Stephanie Insalaco-Wyner, geographers from Florida, comment on differing methods of monitoring the resilience of seagrass meadows in Florida’s ‘Mosquito Lagoon’, following a number of extreme weather events. Florida’s Indian River Lagoon has been an ecosystem in decline going back to 2011, when harmful algal blooms led to a severe decline in seagrass, the foundational component of shallow coastal ecosystems. Seagrass meadows stabilize sediments, improve water clarity and provide critical habitat and forage for species ranging from invertebrates to sea turtles and manatees. Seagrass also generates a significant amount of economic activity in the state of Florida. The loss of seagrass in the Indian River Lagoon System undermined fisheries, tourism and wildlife, ultimately leading to the starvation of more than 1,200 manatees from 2020-25, peaking in 2021-22. Mosquito Lagoon is part of the Indian River Lagoon system that spans 28 miles (45 kilometers), running from Cape Canaveral in the south up to Ponce Inlet in the north. As in the rest of the lagoon system, years of nutrient pollution and recurring algal blooms had diminished seagrass cover to nearly zero by the early 2020s. By most accounts, Mosquito Lagoon had crossed a critical ecological tipping point. In the fall of 2022, hurricanes Ian and Nicole struck Florida’s east coast within six weeks of one another, bringing intense rainfall, storm surges and coastal erosion. In the immediate aftermath, seagrass declined even further. But a few months later, in the spring of 2023, seagrass began to return. Satellite imagery revealed rapid and widespread regrowth. Hannah and I are geographers who study environmental change. Our research documents this unexpected recovery and examines what it may reveal about ecosystem resilience in heavily degraded coastal systems. One of us, Hannah Herrero, is a Volusia County native who grew up around the lagoon. She returned to her hometown at the outset of the COVID-19 pandemic. It was there that some local guides and fishermen she’d known for years suggested that our team should use satellite imagery to look at the state of collapse in the lagoon. The study we designed as a result used satellite imagery and machine learning, a type of artificial intelligence that uses advanced algorithms to learn and predict patterns, to track seagrass dynamics in Mosquito Lagoon before, during and after the storms. This approach allowed us to observe change at a scale and frequency that is difficult to achieve using only traditional field survey methods. Florida Manatee Tracking seagrass from space Monitoring seagrass coverage “the old-fashioned way” involves going into the lagoon and laying out transects, straight lines that cut through a landscape, so standard observations could be recorded. We would then have to boat or wade all along those lines to measure seagrass extent and locations and create digital maps manually to show where it is present. As you can imagine, this is a time-intensive process that’s limited by how far you can boat or swim in a day, and by financial resources. So we decided to use satellite imagery instead. This method is not without its own challenges—water turbidity, or cloudiness, seasonal variability and the patchy nature of vegetation that grows on the bottom of the lagoon all make it difficult to observe seagrass growth directly on the imagery. To address this challenge, our study used imagery from NASA’s Harmonized Landsat–Sentinel program, which combines data from multiple satellites into a consistent record of photos of the same areas taken frequently over time. We analyzed imagery collected between September 2022 and January 2024, focusing on periods before and immediately after the hurricanes and throughout the subsequent recovery. We applied a type of machine learning model called Random Forest to classify each image into seagrass and nonseagrass categories. The machine learning algorithm is informed by training samples collected in the field, but once the model has learned the signature of seagrass, it is able to then apply the classification model to the rest of the lagoon and across time with limited human input. We can then validate this classification. Heading into the field First, we had to train the model using hundreds of GPS points collected in the field over multiple seasons. This step helps to ensure that satellite classifications align with on-the-ground conditions and are accurately interpreting the images. Over several weeks during the summers of 2020 through 2023, our team spent many hours navigating Mosquito Lagoon in a small skiff designed for shallow depths, recording seagrass presence. It wasn’t always easy — Florida summers are intensely hot and humid, and Mosquito Lagoon definitely lived up to its name. But we got to see a wide variety of wildlife, including manatees, dolphins, sea turtles and alligators. And occasionally, on lucky days, we even spotted a roseate spoonbill or reddish egret. Our experience in the field highlighted why this system matters: Mosquito Lagoon is a remarkably vibrant place, teeming with wildlife. These long days on the lagoon, surrounded by its biodiversity and immersed in its unique sense of place, are what anchor the remote sensing data to on-the-ground ecological conditions and make the resulting models credible. The authors wade into Mosquito Lagoon to track seagrass growth as they train their AI model. Captain William B. Wolfson, Grassroots Guide Service, New Smyrna Beach, FL What we found Our analysis reveals three distinct phases of seagrass coverage. First, seagrass declined sharply following hurricanes Ian and Nicole. By December 2022 and early 2023, satellite imagery showed virtually no detectable seagrass across the lagoon. Then, in March 2023, we identified a statistically significant shift. Seagrass began to reappear, initially in small, scattered patches. Finally, during late spring and summer 2023, seagrass expanded rapidly. By July 2023, it covered more than 20% of the lagoon—levels not observed in more than a decade. Coverage then declined again during the winter of 2023–24, as expected based on seasonal growth cycles. But even our last observation, completed in January 2024, showed seagrass covering 4.3% of the lagoon, substantially higher than pre-recovery levels during the winter season. In spring 2026, seagrass in Mosquito Lagoon has remained at stable levels. Although it still experiences fluctuations due to algal blooms, seasonality and other changes in the ecosystem, we have not seen a
Heidi McIlvenny, PhD researcher from Queen’s University Belfast, comments on seagrass meadows in Northern Ireland and how seagrass meadows can recover but only if we tackle the pollution at its source. I spent last summer wading through seagrass meadows across Northern Ireland, from the sheltered waters of Strangford Lough to the exposed coast at Waterfoot Bay. I was collecting seagrass leaves and testing them for nitrogen pollution. Every meadow I visited sits inside a marine protected area – a stretch of sea that’s been given legal protection to safeguard the wildlife living there. And every single one was polluted beyond the limit for healthy seagrass. Seagrass meadows are among the most valuable habitats in our coastal waters. They store carbon, nurture young fish and shellfish, stabilise sediment and buffer shorelines from storms. They are also woven into the heritage of coastal communities who have fished and foraged around them for generations. But they are disappearing worldwide, and nitrogen pollution from farming, sewage and urban runoff is one of the biggest reasons why. It’s easy to assume that designating an area as “protected” keeps the habitat inside it safe. My research shows that, for seagrass, this assumption is dangerously wrong. Physical protection from anchors and dredging means little when pollution flows freely across the boundary from the land. What matters most for seagrass is not lines drawn on a map, but what happens on shore. To understand how much nitrogen pollution seagrass is absorbing, we can measure nitrogen content in the leaves themselves. Seagrass continuously takes up nutrients from the surrounding water, so the chemistry of its tissue works like a long-term pollution record. And my results showed that every meadow in Northern Ireland exceeded the pollution limit. But knowing the pollution level is only useful if you know how much is too much, and what it means for the health of the meadow. To answer that, we pulled together data from 13 countries across the northern hemisphere and found a clear pattern. A catshark shelters among seagrass. Shannon Moran / Ocean Image Bank When nitrogen in the leaves rises above 1.8%, seagrass starts to suffer and loose plant growth. Above 2.8%, the decline accelerates rapidly, and in this danger zone small increases in pollution trigger disproportionately large plant losses. Think of it as a traffic light system: green is below 1.8% where meadows can cope; amber is between 1.8% and 2.8%, where managers should be watching closely and acting to reduce pollution; and red is above 2.8%, where urgent intervention is needed before the damage becomes irreversible. The starkest example of a meadow in the red zone comes from Dundrum Bay, on the County Down coast. According to government assessments, it’s healthy. But my data tells a different story. Nitrogen levels here were nearly double the pollution limit of 1.8%. Surveys over the past decade paint an even bleaker picture: where lush meadows once thrived, dense mats of green algae now smother what little remains. This meadow has likely crossed a tipping point, and may never recover even if we clean up the pollution. A few miles up the coast we see a very different picture. At Castle Espie, beside a wetland reserve in Strangford Lough, a seagrass meadow is thriving. The plants here belong to the same genetic population as struggling meadows elsewhere in the lough. But the difference is that the reserve’s reedbeds and willows act as natural filters, cleaning the water that runs from the land before it reaches the sea. The same species with the same level of marine protection, but dramatically different outcomes. The difference is what happens on land. But current monitoring methods aren’t designed to spot this kind of trouble before it’s too late. An early warning system Current monitoring methods tend to measure how much seagrass is still there. But by the time a meadow visibly shrinks, the damage may already be done. The tissue chemistry approach we used picks up stress signals much earlier, while there is still time to act. The nitrogen thresholds my research identifies could give environmental agencies a practical early warning system: meadows at or above 1.8% need closer watching, and those at or above 2.8% need urgent action to reduce nutrient pollution from catchments. Seagrass meadows can recover but only if we tackle the pollution at its source. That means better management of urban and agricultural runoff, investment in sewage treatment and recognising that marine conservation cannot stop at the high tide mark. If we lose these meadows, we lose their carbon stores, their fish nurseries, the coastal protection they provide, along with a piece of our coastal heritage. More information: This article is republished from The Conversation
Between the 17th and 23rd March 2026, members of the Project Seagrass team were on the Isle of Wight carrying out active restoration as part of the The Solent Seascape Project, the first project of its kind in the UK to initiate seascape-scale restoration. As part of The Solent Seascape Project, Project Seagrass is working to restore 3.5 hectares of seagrass in the Solent. During this spring’s planting efforts, the team planted 175,416 seagrass seeds using the Dispenser Injection Seeding (DIS) method and 1,154 seagrass transplants from our Seagrass Nursery, planting across an area of 1.11 hectares. Find out more about the activity that took place: Fragment Walk The March fieldwork efforts commenced with a Fragment Walk at Priory Bay. Fragment Walks are a community-based seagrass restoration initiative and form one of the approaches to active restoration that Project Seagrass is undertaking on the Isle of Wight as part of The Solent Seascape Project. Seagrass meadows are sensitive habitats which can be easily uprooted. As a result of storms or other disturbances, fragments of seagrass (individual seagrass plants with the rhizome or reproductive root and node system still intact) can become dislodged, uprooted, and washed up onto beaches. Fragment Walks involve collecting and re-planting these dislodged seagrass fragments, giving them another chance to thrive. During March’s Fragment Walk, the team were joined by 11 volunteers. Together, the group walked along the beach from St Helens to Priory Bay collecting over 100 dislodged seagrass fragments which were then re-planted in a dedicated seagrass community garden at Priory Bay. Over 100 seagrass fragments were collected at Priory Bay as part of March’s Fragment Walk. These were re-planted in a Community Garden at Priory Bay. 11 volunteers supported the activity, supporting active restoration on the Island. Planting Preparation Workshop One of the methods used for active seagrass restoration on the Isle of Wight is planting seagrass transplants. This year’s Planting Preparation Workshop took place at Sea View Yacht Club where 17 volunteers helped the team to prepare 1,154 transplants from the Project Seagrass Seagrass Nursery for planting out into the field. The preparation process for the transplants involves carefully attaching bamboo pins to seagrass rhizomes which provides them with increased stability when they are planted out into the field. March’s Planting Preparation Workshop took place at Seaview Yacht Club Seagrass transplants from the Project Seagrass Seagrass Nursery are prepared for planting out into the field by attaching bamboo pins to the rhizome Seagrass Planting Project Seagrass’ planting as part of The Solent Seascape Project is located at two Isle of Wight sites: Priory Bay and Thorness. Alongside the 1,154 seagrass transplants from the Project Seagrass Seagrass Nursery, the team planted 175,416 seagrass seeds across the sites using the Dispenser Injection Seeding (DIS) method, a method developed by The Fieldwork Company. This year’s seed planting incorporated experimental work to compare the germination success of subtidal and intertidal seed populations collected from Isle of Wight seagrass meadows in Yarmouth, Ryde, and Bembridge as part of last summer’s seagrass seed collections. Baseline measurements were taken at our experimental plots including drone images, pH, salinity, and sediment samples. This provenance experiment will help to inform where seeds are collected from for future restoration activity. Over the course of the fieldwork trip the team planting across an area of 1.11 hectares, an important step in the restoration of the Solent’s important seagrass habitats. Project Seagrass Nursery Manager Emily Yates plants seagrass at Thorness using the DIS method Project Seagrass Operations Lead Eve Uncles plants seagrass transplants from the Seagrass Nursery out into the field at Thorness
New research led by scientists at University of California’s San Diego’s Scripps Institution of Oceanography is shining a spotlight on one of the ocean’s most overlooked habitats: seagrass. Led by Scripps Oceanography Ph.D. candidate Rilee Sanders, the study documented the first successful restoration of open-coast seagrass (common eelgrass). The findings offer promising insight into the feasibility of restoring high-value coastal habitats in the future. The work is published in the journal Estuaries and Coasts. Seagrasses act as ecosystem engineers, creating complex underwater habitats that support life along the coast. Around the world, these habitats are increasingly threatened by climate change and human impacts like coastal development, invasive species and overfishing. While most West Coast seagrass research has focused on protected bays and estuaries, this study focused on open-coast areas off Catalina Island. Drawing on nearly a decade’s worth of surveys, the team examined everything from seagrass structure to fish communities and ocean conditions to identify where restoration might succeed. Juvenile señorita (Oxyjulis californica) utilize the protective canopy of the open-coast seagrass restoration site at Button Shell, Catalina Island. Credit Adam ObazaPaua Marine Research Group Two bat rays (Myliobatis californica) soaring over an open-coast eelgrass (Zostera marina) bed on Catalina Island. Credit Adam ObazaPaua Marine Research Group The results were encouraging, as the researchers completed the first transplant of open-coast common eelgrass (also known as Zostera marina). Within a year, the restored site began functioning like a natural meadow, supporting fish communities and ecosystem structure, and by year two, it was even healthier and more biodiverse than natural reference meadows. “Seagrasses are kind of an unsung hero of nearshore ocean habitats,” said Sanders. “They provide nursery habitat for young fish, store carbon in sediments and support immense biodiversity in places that might otherwise be sandy seafloor. Being able to quickly restore that structure and function on the open coast is really exciting.” The findings suggest that open-coast environments could become a valuable new tool for seagrass restoration and conservation in California, especially as coastal development and climate change reduce the available suitable habitat in bays and estuaries. And sometimes restoration has surprising benefits. During monitoring, researchers even captured images of an endangered sea turtle visiting the restored meadow. In short: if we plant seagrass, the ecosystem may follow. More information: This article is republished from PHYS.ORG and provided by the University of California – San Diego. Rilee D. Sanders et al, Open-Coast Eelgrass (Zostera marina) Transplant Catalyzes Rapid Mirroring of Structure and Function of Extant Eelgrasses, Estuaries and Coasts (2025). DOI: 10.1007/s12237-025-01609-x
Nursery intern Iestyn Comey details how fishing in seagrass meadows can be great to improve mental health and are vital nursery grounds for key fisheries species. Fishing is a hard thing to explain to someone who has never done it. There is no better feeling than the moment the line tightens, the adrenaline kicks in, and you pull up your first fish, completely absorbed in something so simple and ancient. Recreational fishing remains one of the most widely enjoyed outdoor pastimes. (Karpiński and Skrzypczak, 2022). But for many people, it is more than just a hobby. It’s a way to reset. It’s one of the few moments when everything slows down and you can think completely immersed in nature. It can be social, or it can be just you and the rod. Either way, that time outdoors—surrounded by nature, waiting and focusing—has a powerful effect on mental health and wellbeing. Science is beginning to catch up with what anglers have long known. Image of typical fishing line, a true way to be one with nature More than a feeling: fishing and mental health Recent UK research involving over 1,700 recreational anglers found that people who fish regularly experience significantly better mental health outcomes than those who fish less often (Wilson et al., 2023). Regular anglers were: 17% less likely to report being diagnosed with depression, schizophrenia, less likely to experience suicidal thoughts, less likely to report harmful coping behaviours. Nearly 9 in 10 anglers also reported that relaxation and unwinding were key reasons they go fishing. This aligns with a growing body of evidence showing that spending time in “blue spaces”—coastlines, estuaries, rivers, and seas— is linked to improved psychological wellbeing (White et al., 2010; Gascon et al., 2017). Blue Mind theory, introduced by Wallace J. Nichols, provides a framework for understanding this effect, suggesting that the mental health benefits of fishing largely arise from immersion in water and aquatic environments, rather than the act of fishing itself. What makes this even more striking is that anglers, as a group, report higher than average levels of mental health challenges. In the same UK study, around 30% reported experiencing suicidal thoughts and over 23% reported having been diagnosed with depression suggesting that many people may actively turn to fishing for its mental health benefits. Every catch has a beginning There is another part of this story that we rarely see. Many fish we love to catch do not begin life in open water, rocky shorelines, or deep offshore. Instead, they begin somewhere more sheltered and hidden. In seagrass meadows. In the UK alone, seagrass meadows provide habitat for around 50 fish species and serve as crucial nursery grounds for juveniles, including cod, pollack, whiting, plaice, herring, and sea bass (Bertelli & Unsworth, 2014). Our new paper in BioScience highlights that this nursery function directly underpins the cultural ecosystem service of recreational fishing, demonstrating that healthy seagrass habitats are integral not only to sustaining fish populations but also to supporting the human experiences and wellbeing derived from angling. Data from Catchwise, a collaboration between Substance, Cefas, and the Angling Trust, further reinforces this connection. Many of the species most frequently caught by recreational fishers in the UK, overlap with species that depend on seagrass during early life stages, showing the practical importance of protecting and restoring these habitats. Across the world, countless marine species rely on seagrass meadows for feeding grounds or during their earliest, most vulnerable stages of life. (James and Whitfield, 2022). Seagrass changes that equation. Its dense leaves slow water movement, trap nutrients, and create a three-dimensional maze that offers both shelter and rich feeding grounds. seagrass meadows support higher fish abundance, faster growth, and higher survival rates than bare sand (Whitfield, 2016). Even if the fish we catch eventually migrate far from the coast into deeper seas, estuaries, or rivers their survival often depended on those first months spent among seagrasses. Catshark in seagrass, Helford, Cornwall, UK Credit: Shannon Moran / Ocean Image Bank So why am I telling you this? The connection is simple: Fewer Seagrass meadows and fewer juvenile fish survive. Fewer fish and poorer catches. Poorer catches and fewer opportunities for people to access one of the most natural, affordable, and culturally accepted forms of mental wellbeing support available. Yet seagrass meadows are declining globally, and much of this loss is driven by human activity. In the UK, declining water quality is one of the biggest drivers. Runoff from agriculture carries excess nutrients in marine ecosystems fuelling algal blooms that block sunlight and as a result prevent seagrass from photosynthesising (Lee, Park and Kim, 2007). Physical disturbance is another key issue, particularly from commercial fishing and boating activity. Bottom trawling can tear up seagrass beds; while anchoring and mooring chains can scar and fragment them. Damage to these habitats ultimately reduces the productivity of the fisheries they support (Unsworth et al., 2017). Seagrass, Isles of Scilly, Cornwall, UK. Credit: Michiel Vos / Ocean Image Bank Protecting the places that protect our wellbeing As recreational fishers, we are connected to seagrass whether we realise it or not. If we want future generations to feel that same tug on the line and that same clearing of the mind, then protecting seagrass is not optional. Supporting seagrass restoration and conservation helps protect: Healthy fish populations, The future of recreational fishing And our own mental wellbeing. To get involved, visit Volunteer – Project Seagrass. References Bertelli, C.M. and Unsworth, R.K.F. 2014. Protecting the hand that feeds us: Seagrass (Zostera marina) serves as commercial juvenile fish habitat. Marine Pollution Bulletin 83(2), pp. 425–429. doi: https://doi.org/10.1016/j.marpolbul.2013.08.011. Gascon, M., Zijlema, W., Vert, C., White, M.P. and Nieuwenhuijsen, M.J. 2017. Outdoor blue spaces, human health and well-being: A systematic review of quantitative studies. International Journal of Hygiene and Environmental Health 220(8), pp. 1207–1221. doi: https://doi.org/10.1016/j.ijheh.2017.08.004. James, N.C. and Whitfield, A.K. 2022. The role of macroalgae as nursery areas for fish species within coastal seascapes. Cambridge Prisms: Coastal Futures 1.
Extreme heat can have a devastating effect on seagrass, but new research from Edith Cowan University (ECU) could shape how these vitally important marine ecosystems are managed and restored. In separate studies carried out on both the west and east coasts of Australia, researchers have investigated how seagrasses stand up to marine heat waves and prolonged ocean warming. Executive Dean of ECU’s School of Science, Professor Marnie Campbell, conducted the research during her time at Central Queensland University. She noted that insights into how different intertidal species respond to elevated water temperatures are critical for informing future seagrass management. “The outcomes demonstrate that the way we protect and restore seagrass will need to change as the climate warms,” Professor Campbell said. Ph.D. candidate Nicole Said from ECU’s Center for Marine Ecosystem Research said that not all seagrass species faced the same climate risk, with her research findings on Western Australian seagrass ecosystems indicating that subtidal seagrass meadows could be restored with more heat-resistant populations of the same species. “By identifying and sourcing heat-tolerant populations—sometimes just kilometers away—we can translate this knowledge into on-the-ground action, incorporating resilient populations into restoration to create climate-ready meadows,” Ms. Said explained. West coast Ms. Said is lead author of the study “Seagrasses are most vulnerable to marine heat waves in tropical zones: local‐scale and broad climatic zone variation in thermal tolerances,” which looked at six species along the Western Australian coast, spanning broad thermal gradients from temperate to tropical climates. The study is published in the journal New Phytologist. “Western Australia is an ideal setting for studying seagrass thermal tolerances, and there is a critical need for this data due to WA being a global hotspot for marine climate impacts,” Ms. Said explained. “We can use this information to look at which species might be vulnerable during future marine heat waves, and which ones we should focus our conservation value on.” The study revealed that seagrasses are most vulnerable to marine heat waves in tropical zones. It also showed that climate risk varied across seagrass species, with a 10-degree Celsius difference in thermal optima, and even neighboring populations showed different heat tolerances. “Some populations are better equipped to deal with the heat, and in some cases, the tough ones might be growing next door,” Ms. Said explained. “This shows that not all species face the same level of risk from climate change, and a one-size-fits-all approach is not appropriate for management of thermally vulnerable seagrass species.” The findings could also benefit restoration of seagrass meadows that have already suffered from thermal warming and marine heat wave events. “We can use this information to help build climate-ready meadows, by migrating plants or seeds from more heat-resistant populations into thermally vulnerable areas.” East coast Professor Campbell’s study “Varying vulnerabilities: Seagrass species under threat from prolonged ocean warming” is a paper published in Limnology and Oceanography that examined the impacts of elevated water temperatures on five intertidal species in Gladstone, Queensland, with a focus on improving seagrass restoration. “This study offers an understanding of how climate change might impact these seagrasses, whose ecological functions are not easily replaced once lost,” Professor Campbell said. “Seagrasses are a critically important ecosystem that provides food, shelter and nursery areas for a wide variety of marine life, so with changing climate, it is at risk in different ways. We wanted to understand how these species react when temperatures reach dangerous extremes, which is becoming more common with climate change.” Professor Campbell said they found intertidal pools where the water was more than 40 degrees for weeks on end. “The tide would go out, and the seagrass would be left high and dry, quite often in little, tiny pockets of water which would reach massive temperatures,” Professor Campbell said. “To restore or manage the species, you have to look at the distinct thermal thresholds of the different species—you can’t treat them all as one. “This knowledge helps us to decide which species to plant where—including the best substrate and water depth; so we can restore these ecosystems more effectively.” Professor Campbell said the species she studied were commonly found in Australia and other parts of the world, with the outcomes leading to global impact. “There were two species that were really good candidates for future-proofing restoration in regions that are warming up,” Professor Campbell said. “Two were highly vulnerable and will require more protection from heat stress, or if you’re going to restore them, you need to find micro-climates that are cooler for them—for example, if they are in the sub-tropics, you would look at temperate areas to restore them.” More information: This article is republished from PHYS.ORG and provided by the Edith Cowan University. Nicole Said et al, Seagrasses are most vulnerable to marine heatwaves in tropical zones: local‐scale and broad climatic zone variation in thermal tolerances, New Phytologist (2025). DOI: 10.1111/nph.70742 Marnie L. Campbell et al, Varying vulnerabilities: Seagrass species under threat from prolonged ocean warming, Limnology and Oceanography (2025). DOI: 10.1002/lno.70156
