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
A new QR code on the Wales Coast Path at Porthdinllaen and Morfa Nefyn reveals the story of the large seagrass meadow in the shallow water. Thousands of people visit this area every year to enjoy its natural beauty, but few are probably aware of the seagrass meadow – estimated
Eelgrass, a type of flowering seagrass found in temperate zones around the world, provides habitat for many species, protects coastlines, improves water quality, sequesters carbon and supports fishing economies. The foundation of a highly productive marine food web, eelgrass’s health is paramount but mysterious. Scientists have long studied how terrestrial
Scientists have warned efforts to protect and restore marine habitats along the UK’s coastline could be hindered by a lack of public knowledge about these initiatives. In the face of climate change and rising sea levels, nature-based coastal solutions (NBCS) are emerging as a sustainable and environmentally friendly way to
Gathaagudu/Shark Bay is located on Malgana (pronounced Mal-guh-nuh) Country. It’s a place of great natural beauty and a UNESCO World Heritage Site. The landscape is a stunning array of colors as the desert meets the ocean. Below the sea’s surface, 4,000 square kilometers of seagrass meadows sway. That’s equivalent to
Seagrass meadows have an important climate protection function due to their long-term carbon storage potential. An international research team led by the Leibniz Institute for Baltic Sea Research Warnemünde (IOW) has now been able to show that seagrass beds have a stronger influence on the carbon and sulfur cycling in
A major global study using teabags as a measuring device shows warming temperatures may reduce the amount of carbon stored in wetlands. The international team of scientists buried 19,000 bags of green tea and rooibos in 180 wetlands across 28 countries to measure the ability for wetlands to hold carbon
The tropical coastlines of Southeast Asia are home to some of the most important and biodiverse marine ecosystems on the planet. However, they are also among its most vulnerable, with areas of coral reefs, mangrove forests, and seagrass beds under increasing threat from a wide range of human activities. To
In autumn 2024, Teigan joined the teams at Project Seagrass and Swansea University to undertake a PhD exploring the influence of water quality on greenhouse gas emissions from seagrass. Teigan’s PhD forms part of Accelerate Seagrass, a collaborative program with Climate Impact Partners, Deloitte, and the National Oceanography Centre to
Seagrass Restoration Efforts to restore seagrass marine habitat at our two restoration sites on the Isle of Wight began in March and April this year under the Solent Seascape Project. A total of 132,000 seeds and 2,160 transplants have been planted across the two sites. There are plans to continue this
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
A new QR code on the Wales Coast Path at Porthdinllaen and Morfa Nefyn reveals the story of the large seagrass meadow in the shallow water. Thousands of people visit this area every year to enjoy its natural beauty, but few are probably aware of the seagrass meadow – estimated to cover the same area as 46 football pitches – and its environmental importance. Now HistoryPoints, Project Seagrass and the National Trust have teamed up to provide on-the-spot information about the meadow on smartphones. Anyone can scan the QR code, displayed at Morfa Nefyn and at Porthdinllaen, to view a page on the HistoryPoints website with concise information, photos and a video of seagrass seeds being collected for restoration of meadows elsewhere around the coast. Seagrass meadows are havens of biodiversity and trap carbon from the atmosphere. Since 2012, HistoryPoints has provided QR codes for display at other 600 places along the 870-mile Wales Coast Path, shedding light on interesting aspects of local human history or natural history. The Porthdinllaen seagrass QR code is the first one dedicated to raising awareness of some of the underwater wildlife which lies close to the path but goes unnoticed by walkers. Leanne Cullen-Unsworth CEO of Project Seagrass, who have been studying the meadows in North Wales for more than a decade, said: “the coast path history points are a fantastic resource for us to share more widely the beauty and importance of this vital habitat. The UK has lost up to 90% of its seagrass over the past century, and so it’s essential that we celebrate and enhance what we have left. We need people to know that seagrass is there and to understand its importance so that more people care about it, this is a great way to help achieve that.” Eve Nicholson of Cyfoeth Naturiol Cymru/Natural Resource Wales, which oversees the path, said: “Walking the Wales Coast Path is a great way to connect with nature along the Welsh coastline at your own pace, offering lots of opportunity to relax and experience the unique Welsh coastline at their own pace. Whilst the sea is your constant companion on the path, what lies beneath the waves is just as intriguing as what’s surrounding you. Many people enjoy the views from the path at Morfa Nefyn and Porthdinllaen and we hope that people will discover what underwater natural history there is beneath them during their walks.” Find out more about the Seagrass Ocean Rescue: North Wales programme and explore the new HistoryPoints webpage.
Eelgrass, a type of flowering seagrass found in temperate zones around the world, provides habitat for many species, protects coastlines, improves water quality, sequesters carbon and supports fishing economies. The foundation of a highly productive marine food web, eelgrass’s health is paramount but mysterious. Scientists have long studied how terrestrial invertebrate herbivores such as insects (aphids, beetles) and gastropods (snails, slugs) frequently act as vectors, transmitting plant diseases through their feeding activities and often creating wounds on plants’ surfaces that make it easier for pathogens to enter. But how this works, and how pernicious the problem is, has been harder to study underwater in the ocean. In two new papers, Cornell plant-herbivore experts and researchers from the Cornell Institute for Computational Sustainability joined forces to show the significant impacts of herbivores like sea snails on the spread of seagrass wasting disease. Grazing by small herbivores was associated with a 29% increase in the prevalence of disease, which contributes to huge losses in meadow areas from San Diego to Alaska. The two papers are “Invertebrate Herbivores Influence Seagrass Wasting Disease Dynamics“ and “Seagrass Wasting Disease Prevalence and Lesion Area Increase with Invertebrate Grazing Across the Northeastern Pacific,” the former published in the December 2024 issue of Ecology, and the latter in the January 2025 issue. The research brings together the work of Drew Harvell, professor emerita of marine ecology in the Department of Ecology and Evolutionary Biology; Olivia Graham, a marine disease ecologist and postdoctoral researcher in the Department of Ecology and Evolutionary Biology; Lillian Aoki, an eelgrass ecologist and former postdoctoral researchers in the Department of Ecology and Evolutionary Biology; Carla Gomes, the Ronald C. and Antonia V. Nielsen Professor of Computing and Information Science, director of the Institute for Computational Sustainability, and a Schmidt AI2050 Senior fellow; and Brendan Rappazzo, doctoral student in computer science. “The cool thing about these two papers coming out at the same time is that they are two ends of the same project, from controlled lab experiments to continental scale field surveys” Harvell said. “This is pioneering work in an understudied system, the first study to show the role of these herbivores in facilitating disease at a huge latitudinal scale.” Their work shows that isopods and snails create open wounds on eelgrass when they graze; lab experiments verify increased disease in the wounded plants. The researchers also showed that sea creatures can be picky eaters: Crustaceans called amphipods selectively consumed diseased eelgrass, while the isopods and snails prefer to feed on pristine leaves, meaning different herbivores have contrasting impacts on seagrass health. Gomes and Rappazzo have accelerated the effort to identify and quantify the problem via the Eelgrass Lesion Image Segmentation Application (EeLISA, pronounced eel-EYE-zah), an AI system they have developed that, when properly trained, can quickly analyze thousands of images of seagrass leaves and distinguish diseased from healthy tissue, thus allowing continental scale studies. (a) Evidence of snail grazing (left) that damages leaf surfaces in contrast to crustacean grazing (right) that consumes the full thickness of the leaf tissue (photo credit Lillian R. Aoki). (b) Across all meadows and years, leaves with grazing scars were more likely to be diseased; labels show counts of leaves in each category and box widths are proportional to the count (total n = 1351). Credit: Ecology (2025). DOI: 10.1002/ecy.4532 Researchers collected thousands of eelgrass leaves at 36 sites along the Pacific Coast from Southern California to Alaska, uploading high resolution images of each plant. Gomes and Rappazzo used algorithms and machine learning to train a computer using state-of-the-art image segmentation to recognize necrotic dark spots on eelgrass blades and correctly identify them, separating disease-caused lesions from other kinds of leaf damage. “We came up with a positive feedback loop,” Rappazzo said. “Researchers Olivia Graham and Morgan Eisenlord would correct EeLISA, which would update immediately. When a new set of samples would come in, the AI would do better immediately. The accuracy is more consistent than humans, which allows for scalability—to have humans analyzing the images by hand would take 20 minutes per image. EeLISA can do it in a second. The whole continental-scale study took 30 minutes to run.” Gomes describes Eelisa as a novel AI approach to solve impactful real-world problems. “The collaboration has removed the historic bottleneck of interpreting data,” Gomes said. “We continue to enhance Eelisa with the capabilities of multimodal language models, enabling it to explain its scientific reasoning—why it determines the presence or absence of disease. It can also engage in conversation with researchers, making the process more interactive and insightful.” “Working with Carla and Brendan has allowed us to do so much more work,” Graham said. “Eelgrass is globally distributed and it’s not an exaggeration to say these seagrass meadows have superpowers. They are our rainforest of the sea. As incredibly valuable habitat for marine fish and vertebrates, they support vital fisheries.” Recently, international researchers have contacted Graham with requests for access to EeLISA, she said. There are a number of global stressors for seagrass meadows, especially as ocean temperatures rise, but Graham, who leads the deeper-water SCUBA surveys and lab experiments, came at the question as a disease ecologist, asking first if these herbivores were directly transmitting pathogens. The answer was no, it was indirect transmission, the bite marks providing an entry point for infection. Better knowledge of both the mechanisms—both how herbivory can influence disease as well as the ecological impacts—is needed, said Lillian Aoki ’12, lead on the second paper and an ecosystem ecologist and coastal scientist at the University of Oregon. “We need to know when and where herbivory might be important to disease dynamics and ecosystem stability,” said Aoki, also a former postdoc in Harvell’s Cornell lab. “This information will help us to better predict changes, such as disease outbreaks, and to manage coastal habitats.” More information: This article is republished from PHYS.ORG and provided by Cornell University. Olivia J. Graham et al, Invertebrate herbivores influence seagrass wasting disease dynamics, Ecology (2024). DOI: 10.1002/ecy.4493 Lillian R. Aoki et al, Seagrass wasting disease
Scientists have warned efforts to protect and restore marine habitats along the UK’s coastline could be hindered by a lack of public knowledge about these initiatives. In the face of climate change and rising sea levels, nature-based coastal solutions (NBCS) are emerging as a sustainable and environmentally friendly way to protect our shores. These innovative solutions—which include living shorelines, engineered reefs, and restoration of saltmarshes and dunes—offer a greener alternative to traditional hard defenses like seawalls and barriers. However, new research reveals that while NBCS are preferred by many for their environmental benefits, public understanding of their effectiveness lags behind. In a study published in the Journal of Environmental Management, researchers surveyed over 500 UK residents and found a striking divide between public preference and their perception of effectiveness. Most respondents expressed a preference for nature-based coastal solutions due to their sustainability and aesthetic appeal. Yet hard defenses, which were long-established and visibly effective, remained widely thought-of as the most reliable way to mitigate coastal risks like flooding and erosion. Spatial distribution in preferences and perceived effectives for the two active coastal management strategies considered: hard defenses and nature-based coastal solutions. Credit: Journal of Environmental Management (2024). DOI: 10.1016/j.jenvman.2024.123413 The study highlights a critical knowledge gap. Although NBCS offer significant environmental advantages- including carbon sequestration, enhanced biodiversity, and community resilience—their long-term effectiveness is not well understood by the public. This disconnect could hinder efforts to implement NBCS at scale, despite growing calls from the coastal science community to adopt these solutions as a cornerstone of sustainable coastal management. To bridge this gap, researchers emphasize the need for greater public engagement and education about nature-based initiatives. Collaborative approaches, such as systems mapping, could play an important role in involving local communities in the decision-making process. By fostering dialogue among residents, scientists, and policymakers, systems mapping can help ensure that coastal management strategies are both inclusive and effective. Dr. Scott Mahadeo, from the School of Accounting, Economics and Finance at the University of Portsmouth, explains, “Nature based coastal solutions offer a promising path toward sustainable coastal management, combining environmental benefits with resilience against climate challenges. However, our findings highlight a clear knowledge gap between the scientific community’s advocacy for these solutions and the public’s understanding of their effectiveness. Bridging this gap through meaningful dialogue and inclusive decision-making will be key to fostering widespread support and ensuring robust, long-term coastal policies.” The study highlights that coastal zones hold deep socio-cultural significance, from family heritage and community cohesion to recreation and environmental stewardship. Researchers say that any changes to these landscapes can profoundly impact the lives and identities of coastal residents and users. This is why public support and understanding are crucial for the successful adoption of NBCS and other coastal management strategies. Dr. Mahadeo adds, “As the UK and the world grapple with the challenges of climate change, balancing innovative solutions with community needs is essential. The path forward lies in building trust, sharing knowledge, and working together to safeguard our coasts for generations to come.” The University of Portsmouth is involved in several projects that use nature as a potential solution to climate-related or pollution-related issues. These include the Rapid Reduction of Nutrients in Transitional Waters (RaNTrans) project, which is exploring how nature-based approaches can improve and protect marine ecosystems. Restoration projects are also underway across the south coast of England, including the pioneering Blue Marine Foundation’s Solent Oyster Restoration Project, and the UK’s first seascape restoration project the Solent Seascape Project. Both projects are based at the University of Portsmouth’s Institute of Marine Sciences in Langstone Harbour, and aim to restore multiple habitats such as oyster reefs, seagrass meadows, saltmarsh and birds, to reconnect and revive our ailing coastal waters. This latest study was conducted by a team of interdisciplinary scientists—in coastal geomorphology, environmental economics, and human geography—and focused on public perceptions of coastal management in the UK. Using innovative survey and analysis techniques, the authors hope the research will help develop more sustainable and inclusive coastal policies. More information: This article is republished from PHYS.ORG and provided by the University of Portsmouth.
Gathaagudu/Shark Bay is located on Malgana (pronounced Mal-guh-nuh) Country. It’s a place of great natural beauty and a UNESCO World Heritage Site. The landscape is a stunning array of colors as the desert meets the ocean. Below the sea’s surface, 4,000 square kilometers of seagrass meadows sway. That’s equivalent to 226 AFL footy fields. The Shark Bay Heritage Area is home to 12 of the world’s 72 seagrass species. Unfortunately, more than a quarter of the seagrass died during the 2010/11 marine heat wave. To restore the seagrass, a deep knowledge of the area and its plants are needed as well as scientific tools for genetic testing. Malgana mob brought their knowledge and UWA researchers brought their tools. Together, they’re bringing the wirriya jalyanu back to life. A deep connection Malgana people have a 30,000-year connection with Gathaagudu. They have a deep knowledge of Country and are passionate about looking after the area. Aunty Pat is a Malgana Gantharri/Elder. She says Gathaagudu is paradise. “If we look after Country, Country will look after us,” says Aunty Pat. Malgana people had known Sea Country was changing for a long time. “The fishermen knew it,” says Aunty Pat. “Fishermen know Sea Country better than anyone. You talk to any of those fishermen and they will tell you stories about the changes in biology and the marine environment.” UNESCO only recognizes Gathaagudu as an important ecological site, not a cultural site. “We’re trying to [get] our cultural values listed alongside our natural values,” says Aunty Pat. “They’re of equal importance.” These cultural values and knowledge are key to the wirriya jalyanu restoration to provide a broader historical context of Sea Country in Gathaagudu. Teamwork Dr. Elizabeth Sinclair is an Adjunct Senior Research Fellow at UWA. She worked with Aunty Pat and Malgana Traditional Owners to restore the seagrass. Sinclair says researchers have been working on the seagrass for around 15 years. Seagrass grows extremely well in Gathaagudu because the bay area is very shallow, has a sandy bottom and has no big ocean swells. The main seagrass disturbance is dugongs feeding on it. When seagrass is gone, the sandy floor is left exposed to tides. The sand shifts a lot, making the water cloudy. With sand constantly moving, it’s difficult for new plants to grow. This creates a system that’s hard to reverse. “By the time the heat wave came along and in the following years, it was clear that parts of the seagrass meadow were not going to recover naturally and they needed a bit of help,” says Sinclair. Sinclair and the research team looked at genetic markers in the seagrass DNA to understand how the population was structured and how to best restore it. Dugong in a seagrass meadow. Credit: via SeagrassWatch Distribution There are two large species of seagrass that grow on Gathaagudu Sea Country: ribbon weed and wire weed. These plants can grow up to 2 meters tall, creating an underwater forest and crucial habitat for marine life. Growing different types of seagrass requires different strategies. Ribbon weed grows like lawn, with new shoots emerging from the sand. “If you stick your head underwater, all you see is the green shoots,” says Sinclair. “You don’t see [a] massive network of roots.” In Gathaagudu, most of the ribbon weed is one giant clone that is 180 kilometers long. That’s longer than the drive from Perth to Bunbury. It’s the largest known plant on Earth. Knowing how the seagrass is genetically connected informs how the team approaches restoring the meadow. Wire weed grows entire seedlings that break off and float around until they land in the sand. This distribution strategy means wire weed has much more genetic diversity spread further around the bay. “We have the genetics to understand how the plants are related and then we use that information to figure out which plants to collect and where to grow them,” says Sinclair. Underwater gardening The Malgana rangers were heavily involved in the restoration process. “Rangers collected a lot of the restoration material because some now have dive tickets,” says Sinclair. “If you’re working in really shallow water, you can do it on a snorkel, but it’s much easier to do it on scuba.” To collect ribbon weed, rangers would take 10–15cm cuttings. These could be replanted and held in place with a U-shaped piece of wire for about 6 months until they grew new roots. For the wire weed restoration, the team collected seedlings and replanted them at a new location. Instead of being secured with wire, they would hang onto snaggers, a “sand-filled sausage” with a hessian coating. The hessian provided an anchor for the wire weed seedlings to attach to. Aunty Pat says the rangers loved working with the research team because it was a meaningful way to care for Country. “They couldn’t get enough of it,” says Aunty Pat. “To be working in a trial like that, they learned so much. They were happy to be doing something that was meaningful.” Ribbon weed meadow. Credit: Rachel Austin via UWA ‘Medicine for us’ Opportunities for Malgana people to return to Country are few and far between. They can’t participate on a regular basis because of a housing shortage at Gathaagudu. “The Malgana Aboriginal Corporation currently have several rangers in the program, unfortunately everyone has to rely on staying with family or friends who live in Gathaagudu because there isn’t enough accommodation due to the housing crisis,” says Aunty Pat. These types of partnerships enable Malgana people to work on Country and the younger generation the chance to reconnect to the land. “It helps them with their healing [and] their cultural and personal identity,” says Aunty Pat. Restoration team filling seagrass ‘snaggers.’ Credit: Gary Kendrick, UWA Shared knowledge “Shared knowledge leads to an improved understanding of our environment,” says Sinclair. “As Western researchers, we come in, look at a site and focus on one little thing … We have fairly narrowly focused research areas. When you start talking with Traditional Owners,
Seagrass meadows have an important climate protection function due to their long-term carbon storage potential. An international research team led by the Leibniz Institute for Baltic Sea Research Warnemünde (IOW) has now been able to show that seagrass beds have a stronger influence on the carbon and sulfur cycling in subtropical coastal areas than previously thought. Of particular interest is the important role of sulfur, which stabilizes organic carbon, regardless of whether it is sequestered in the calcareous sediments of subtropical seagrass meadows or remains in dissolved form. The results of the study were recently published in Communications Earth & Environment. Seagrass ecosystems are particularly worthy of protection as they provide shelter and food for a wide diversity of marine species and act as natural wave breakers that reduce coastal erosion. They also store so-called “blue carbon”—carbon that stays trapped in the ocean and in coastal ecosystems for a long time and therefore cannot have a climate-damaging effect as carbon dioxide (CO2). Seagrass not only stores carbon via photosynthesis in its plant components, but also buries the organic material of other organisms that accumulates in the dense plant cover in its root sediments. How do subtropical seagrass meadows ‘tick?’ “It has been known for some time that not all seagrass meadows ‘tick’ in the same way when it comes to carbon storage. Tropical and subtropical seagrass meadows in particular can sometimes release more carbon than they store,” says Mary Zeller. The marine chemist is an expert in biogeochemical seabed processes and lead author of the new study on the seagrass carbon cycle. “However, as seagrass meadows are particularly widespread in warm ocean regions, we wanted to take a close look at the processes that ultimately determine their carbon balance. This is the only way to correctly estimate their climate protection potential,” says the scientist, who now works at MARUM—Center for Marine Environmental Sciences at the University of Bremen, but was a researcher in IOW’s Geochemistry & Isotope Biogeochemistry working group during the seagrass study. Zeller and her German-American research team focused on subtropical seagrass beds located in Florida Bay in the south of the United States. In order to understand whether and how organic matter—and therefore carbon—is released from the sediments into the water column, they combined state-of-the-art geochemical and molecular methods to analyze sediments, pore water and the surrounding water. The focus of the involved IOW researchers Zeller and Michael Böttcher was to analyze various stable isotopes as biogeochemical markers to understand the complex matter transformation processes, as well as to employ a special method of high-resolution mass spectrometry, which allows the determination of the molecular formula of individual molecule types in complex mixtures of organic molecules. Porewater and sediment inorganic and stable isotope geochemical data. Credit: Communications Earth & Environment (2024). DOI: 10.1038/s43247-024-01832-7 Surprisingly close coupling of the sulfur and carbon cycles The researchers found that almost 10% of all organic matter of the investigated seagrass meadows is bound to their calcareous sediments. This type of sediment is a characteristic of tropical and subtropical seagrass ecosystems, because in the warm environment the metabolic processes of the seagrass plants cause carbonate, which is dissolved in the seawater, to be converted into lime that accumulates in the root area. If these sediments disintegrate, the bound organic substances can dissolve and enter the water column, making them potentially available again to the marine carbon cycle. “We were able to provide direct proof for the first time that seagrass sediments actually release organic carbon. In particular, our molecular analyses have shown that the dissolved organic molecules in the surrounding water correspond to 97% in structure and composition with the lime-associated organic material in the sediments,” Zeller explains. A crucial role in the mobilization of organic substances from the sediments is played by the sulfur chemistry in the seabed, which the seagrass meadows stimulate like a kind of biocatalyst: Their roots actively transport oxygen into the sediment, which facilitates the oxidation of sulfur compounds by microorganisms. This produces acid, which causes the calcareous sediments at the seagrass roots to partially disintegrate, releasing previously bound organic matter. Additionally, these microbial processes produce highly stable organic sulfur compounds that are largely resistant to biological decomposition and degradation by the UV radiation of sunlight. Improved modeling of the climate protection potential of seagrass “The fact that the sedimentary and dissolved carbon pools in seagrass meadows are so closely coupled was previously unknown and was therefore not adequately taken into account in climate modeling,” comments Zeller on the results of the study. “In this context, it is also important that although the organic sulfur generated in seagrass beds mostly exists in dissolved rather than particulate form, it is apparently still a very long-lived carbon reservoir that cannot be easily metabolized into climate-active CO2,” Zeller continues. According to the marine chemist, the study could help to improve modeling of the “blue carbon” storage potential of the widespread tropical and subtropical seagrass meadows. “However, further research is needed to clarify whether the mechanisms found here are universal—i.e., whether they also apply to other ecosystems with similar rhizosphere processes, such as mangroves. It also needs to be clarified whether and what kind of impact environmental changes such as climate change have on these processes,” concludes Zeller. More information: Mary A. Zeller et al, The unique biogeochemical role of carbonate-associated organic matter in a subtropical seagrass meadow, Communications Earth & Environment (2024). DOI: 10.1038/s43247-024-01832-7 This article is republished from PHYS.ORG and provided by Leibniz-Institut für Ostseeforschung Warnemünde.
A major global study using teabags as a measuring device shows warming temperatures may reduce the amount of carbon stored in wetlands. The international team of scientists buried 19,000 bags of green tea and rooibos in 180 wetlands across 28 countries to measure the ability for wetlands to hold carbon in their soil, known as wetland carbon sequestration. While tea bags may seem an unusual instrument to measure this phenomenon, it is a proven proxy method to measure carbon release from soil into the atmosphere. However, this is the first time teabags have been used for a large-scale, long-term study and the tea leaves have revealed which types of wetlands are leaking the most carbon. RMIT University’s Dr. Stacey Trevathan-Tackett led the study as part of an Australian Research Council DECRA Fellowship while at Deakin University. “Climate effects on belowground tea litter decomposition depend on ecosystem and organic matter types in global wetlands” is published in Environmental Science and Technology. The global study involved 110 co-authors on the paper, along with many others who helped, such as undergraduate students and citizen scientists. Core team members included Dr. Martino Malerba and Professor Peter Macreadie from Deakin University and RMIT, Dr. Sebastian Kepfer-Rojas from the University of Copenhagen in Denmark and Dr. Ika Djukic from The Swiss Federal Institute for Forest, Snow and Landscape Research WSL. “This is the first long-term study of its kind, using this teabags method, which will help guide how we can maximize carbon storage in wetlands and help lower emissions globally,” said Trevathan-Tackett, who is now in RMIT’s School of Science. “Changes in carbon sinks can significantly influence global warming—the less carbon decomposed means more carbon stored and less carbon in the atmosphere.” Map of TeaComposition H2O sites across eight macroclimatic zones. Credit: Environmental Science & Technology (2024). DOI: 10.1021/acs.est.4c02116 Reading the tea leaves Tea bags provide a simple and standardized way to identify how climate, habitat type and soil type influence carbon breakdown rates in wetlands. At each site, scientists buried between 40 and 80 tea bags about 15 cm underground and collected these at various time intervals over three years, tagging their GPS location. They then measured their remaining organic mass to assess how much carbon had been preserved in the wetlands. The project used the two types of tea bags (green and rooibos) as measures for different kinds of organic matter found in soils. Green tea consists of organic matter that decomposes easily, whereas rooibos decomposes more slowly. Using both types of tea bags in this project enabled the researchers to gain a more comprehensive picture of the wetlands’ capacity for carbon storage. “This data shows us how we can maximize carbon storage in wetlands globally,” Trevathan-Tackett said. The Findings The team studied the effect of temperature in two ways: using local weather station data for each site and comparing differences in climate regions. “Generally, warmer temperatures led to increased decay of organic matter, which translates to reduced carbon preservation in soil,” Trevathan-Tackett said. The two tea types acted differently with increasing temperature. “For the harder to degrade rooibos tea, it didn’t matter where it was—higher temperature always led to more decay, which indicates that types of carbon we’d typically expect to see last longer in the soil were vulnerable to higher temperatures,” Trevathan-Tackett said. “With increasing temperatures, the green tea bags decayed at different rates depending on the type of wetland—it was faster in freshwater wetlands but slower in mangrove and seagrass wetlands. “Increasing temperatures may also help boost carbon production and storage in plants, which could help offset carbon losses in wetlands due to warmer weather, but this warrants further investigation with future studies.” Freshwater wetlands and tidal marshes had the highest tea mass remaining, indicating a greater potential for carbon storage in these ecosystems. The study’s findings are helping piece together the puzzle of wetland carbon sequestration on a global scale. Within the terrestrial TeaComposition initiative led by Djukic, information on litter decomposition has been collected at about 500 sites worldwide resulting in several peer-review publications. “Applying the common metric across aquatic, wetland, marine and terrestrial ecosystems allows for a conceptual comparison and understanding of key drivers involved in the control of global litter carbon turnover,” Djukic said. “Now that we are starting to get a better understanding of which environments are storing more carbon than others, we can use this information to ensure we protect these areas from environmental or land-use change.” The researchers will combine the data from this project with data from similar studies of land-based carbon sinks, including forests, to inform designs of predictive global models. More information: Stacey M. Trevathan-Tackett et al, Climate Effects on Belowground Tea Litter Decomposition Depend on Ecosystem and Organic Matter Types in Global Wetlands, Environmental Science & Technology (2024). DOI: 10.1021/acs.est.4c02116 This article is republished from PHYS.ORG and provided by RMIT. Explore our blog for insights on the latest research from across the globe. Click here
The tropical coastlines of Southeast Asia are home to some of the most important and biodiverse marine ecosystems on the planet. However, they are also among its most vulnerable, with areas of coral reefs, mangrove forests, and seagrass beds under increasing threat from a wide range of human activities. To try and better understand those potential threats, a study by an international team of researchers has provided the first detailed assessment of activities taking place within coastal and marine habitats and the impact they have on those ecosystems. The research focused on case study sites in Indonesia, the Philippines, Vietnam and Malaysia, including marine protected areas in UNESCO Man and the Biosphere (MAB) Reserves as well as a Marine Park. Of the 26 activities that were examined, it found that particular fishing techniques—and tourism and recreation—posed the greatest threat to the ecosystems. The fishing practices, including trawling and the use of gill and seine nets, were shown to cause physical pressures such as abrasion, smothering, siltation and total habitat loss. Meanwhile, tourism activities result in different pressures such as organic enrichment, litter and pollution, in particular affecting coral reef habitats. With fishing and tourism being critical to the region’s economy, the researchers hope that highlighting their potential to impact specific locations could help ensure they can be conducted in a more sustainable manner in the future. The study, published in the Journal of Applied Ecology, was led by researchers from the University of Plymouth and involved colleagues from across Southeast Asia. It was carried out as part of Blue Communities. Dr. Fiona Culhane, who carried out the research as part of a Postdoctoral Research Fellowship at the University of Plymouth, and is currently a Postdoctoral Researcher at the Marine Institute in Ireland, is the study’s lead author. She said, “These sites are globally significant for their high marine biodiversity, but are at high risk of pressures from human activities. This work, carried out in collaboration with local communities and in-country researchers, has demonstrated that different locations experience different risks, according to the level of human activities in the sea. “By better understanding how human activities are impacting various marine habitats, and the ecosystem services they provide, we can provide local stakeholders and marine managers with clearer evidence that they can use to inform future action.” Professor Melanie Austen, Professor of Ocean and Society at the University of Plymouth and lead of the Blue Communities program, added, “This study is a powerful example of strong collaboration between researchers from the Global South and Global North. “Its aim, and that of the entire program, has been to provide much needed analysis and information to help coastal communities live within the environmental limits of the natural marine resources.” In addition to forms of fishing and tourism, the research explored the importance and impact of activities including waste disposal, sand mining, aquaculture, coastal infrastructure development, and antique exploration. It then mapped whether, and to what extent, each activity caused forms of disruption including light, noise and water pollution, as well as physical damage to the coastline and seabed and the habitats they contained. Across the different countries, there was variation in the activities posing the greatest pressures with, for example, high risk coming from seine nets in Vietnam, fish farming in Malaysia and pots, traps and barricades in the Philippines. There were also differences across the main habitat types, with trawling and blast finishing among the activities posing the greatest risk to coral reefs, while shrimp farming placed the greatest pressure on mangroves, and trawling and tourism introduced the highest risk to seagrass. Dr. Amy Y. Then, Associate Professor in the Institute of Biological Sciences at the Universiti Malaya in Malaysia, said, “Findings from this paper challenge the way we think about spatially managing multiple economic activities and their impacts on vital coastal ecosystems. “By identifying interactions between these activities and the habitats where they take place, we are able to make better marine spatial management decisions to ensure sustainability and resilience of these socio-ecological systems and their functioning.” Dr. Radisti Praptiwi, researcher at the National Research and Innovation Agency in Indonesia, added, “This is an important study, especially in the context of data-poor regions such as Indonesia. “Research on understanding the impact chains linking activities and pressures to the marine environment can not only help identify the types of activities and habitats to be prioritized for management purposes, but also highlights areas for further research required for evidence-based policymaking.” More information: Fiona Culhane et al, Assessing impact risk to tropical marine ecosystems from human activities with a Southeast Asian example, Journal of Applied Ecology (2024). DOI: 10.1111/1365-2664.14812 This article is republished from PHYS.ORG and provided by the University of Plymouth. Explore our blog for insights on the latest research from across the globe. Click here
In autumn 2024, Teigan joined the teams at Project Seagrass and Swansea University to undertake a PhD exploring the influence of water quality on greenhouse gas emissions from seagrass. Teigan’s PhD forms part of Accelerate Seagrass, a collaborative program with Climate Impact Partners, Deloitte, and the National Oceanography Centre to fund UK seagrass recovery and unlock long-term finance to save and reinstate vital seagrass meadows. Find out more about the Accelerate Seagrass program here. We spoke to Teigan about her PhD and what inspired her to pursue research in seagrass ecosystems. Read the full Q&A below: What inspired you to pursue research in seagrass ecosystems? From the moment I first learned about seagrass meadows during my second year of university, I was captivated. I found it astonishing that these vital ecosystems exist while we still understand so little about their dynamics and functions. For my third-year dissertation, I knew I wanted to complete a seagrass-based project. I explored the feasibility of using satellite imagery to track seagrass populations. I developed a model employing image classification techniques to predict seagrass distribution, further deepening my appreciation for the field. This is what sparked my passion for pursuing research in seagrass ecology. Seagrass is truly extraordinary, and I am continually inspired by its unique ecological role and significance. Can you share an interesting fact about seagrass that most people might not know? Here are two of my favourite facts about seagrass that most people may not know! Some species of seagrass exhibit remarkable resilience with instances of growth documented as far north as Greenland! Additionally, despite covering just 0.1% of the ocean floor, seagrass ecosystems play a crucial role in mitigating the impacts of global warming, highlighting their ecological significance. What’s the most fascinating discovery you’ve made so far in your research? I have been involved in this project for just under two months, so I am still in the process of reviewing literature and familiarizing myself with potential site locations to complete the gas analysis. However, one notable realisation is the significant gap in knowledge regarding the role of seagrass in greenhouse gas emissions. Surprisingly, only a handful of studies have addressed this topic. What is the biggest challenge you will face in your research into greenhouse gas emissions from seagrass, and how do you think you’ll overcome it? The most significant challenge I anticipate is constructing the chamber required for the gas analysis. This will be my first experience designing and building field equipment. To address this, I plan to collaborate closely with experts who previously developed suitable chamber designs to ensure the equipment is fit for purpose. Another challenge I anticipate is the microbial work associated with this project. While I have limited experience completing microbial work, I will work closely with my second supervisor and experienced PhD students to acquire the necessary skills and support for this aspect of the project.
Seagrass Restoration Efforts to restore seagrass marine habitat at our two restoration sites on the Isle of Wight began in March and April this year under the Solent Seascape Project. A total of 132,000 seeds and 2,160 transplants have been planted across the two sites. There are plans to continue this planting in spring 2025 using the same methods. Continued monitoring of the restoration sites and WWF seagrass planting trials are undertaken during fieldwork on a monthly basis. Summer Seagrass Seed Harvest During July, we collected seagrass seeds (Zostera marina) from three meadows around the Isle of Wight. We were joined by 117 volunteers and some of our funders and project partners as part of our seagrass seed harvesting wade and pick event. We collectively harvested 101, 710 seeds in total, which will contribute towards 2025’s restoration efforts. Seagrass Safe Sailor We’ve been working with the boating community on the island to explore Advanced Mooring Systems (AMS), and promote seagrass safe sailing practices. Two AMS have been designed and are in the final stages of being installed at Seaview. These AMS provide a demonstration of how AMS can work safelyin a challenging tidal environment with moving sediment and currents, whilst reducing scarring on the extensive seagrass meadow here. In 2025, we’ll be monitoring seagrass recovery at Seaview, and working with local stakeholders to map the seagrass meadow. You can explore our Seagrass Safe Sailor resources here. Fragment Walks This year we, and many volunteers have also been restoring seagrass through fragments (washed up seagrass). We have: Set up two fragment collection points at St Helen’s and Arc Biodiversity in Sandown Run eight fragment collection walks Planted 329 plants over 17m² Run two school-focused fragment collection walks Worked with over 200 volunteers. To find out more about our Fragment Walk initiative visit our blog article. Looking Back and Moving Forward: A Big Thank You to Our Volunteers! This year has been incredibly busy, and we couldn’t have succeeded without our amazing volunteers. Your dedication has been invaluable. As we plan for an exciting 2025, we’re eager to welcome familiar faces back and meet new ones. Let’s make next year even better together! Thank you for being a vital part of the seagrass community.
