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
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
Two new studies call for clear framework conditions for CO2 sequestration in coastal areas, including a digital twin for projections and an independent body for certification and new legal structures for monitoring. The two papers led by researchers from Helmholtz-Zentrum Hereon were recently published in Environmental Research Letters and Elementa. So-called “blue carbon ecosystems”
Seagrasses are special: they are the only flowering plants that have returned to sea from land. They are also known as the “lungs of the oceans” because of their ability to photosynthesize. And with the exception of Antarctica, they can be found on all continents, where they form extensive underwater
We have just launched a journal club for the Project Seagrass team. These monthly meetups work much like a book club, members of the team each suggest a relevant scientific paper, vote on their favourite, then read the winning paper prior to meeting. During the journal club we critically discuss
Seagrass meadows play a critical role in keeping our oceans healthy and stocked with food, providing valuable nursery habitat to over 1/5th of the world’s largest 25 fisheries. Seagrass meadows are also important to small-scale fisheries, particularly as a place to find and collect a reliable source of food with some
Researchers from the University of Liège (BE) studied the fate of the material produced by Posidonia seagrass meadows. This study, carried out in the Mediterranean Sea at STARESO, shows that the dead leaves of what is commonly known as Neptune grass accumulate in shallow areas, where they break down like
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.
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
Two new studies call for clear framework conditions for CO2 sequestration in coastal areas, including a digital twin for projections and an independent body for certification and new legal structures for monitoring. The two papers led by researchers from Helmholtz-Zentrum Hereon were recently published in Environmental Research Letters and Elementa. So-called “blue carbon ecosystems” for CO2 storage on the coasts and in the ocean can be seagrasses, mangroves or salt marshes, for example. Whether they help to achieve the climate targets and how this can be achieved still needs to be researched in more detail. Projects for CO2 storage are increasingly being initiated by science and industry. But the risks need to be better researched and regulated, say the authors. International legislation is needed for this. Only then could a blue carbon industry be established. Seagrass, pictured here in Florida, could be an option for CO2 storage. Credit: Hereon/Bryce van Dam Clear rules for an industry with a future Regulation through legislation and evaluation are important, says lead author Bryce von Dam from the Hereon Institute of Carbon Cycles. However, this can only be achieved with an international, overarching organization for monitoring, reporting and verification. This organization could issue certificates and create fair conditions. The Paris Climate Agreement is intended to help regulate carbon removal. But until it is fully ratified, there must be other verification bodies. Furthermore, smaller projects should not be disadvantaged—as long as they demonstrably remove greenhouse gases from the atmosphere, say the authors. “In addition, a digital twin that models baseline scenarios and shows what the carbon cycle would look like without blue carbon activities can help. This works well if it collects real data in real time,” says von Dam. The twin should create AI-supported “what-if scenarios” regarding the effectiveness of storage methods. Stronger links between business and science Hereon Institute Director Helmuth Thomas and other researchers have come to the conclusion that the role of coastal and marine ecosystems can contribute to combating climate change. “But only if we find new international governance and legal frameworks.” This is also important in order to recognize unexpected side effects. Only with a clear legal definition could science, business and politics jointly create frameworks. One example would be to clarify liability issues. “Some measures in the wrong place can even lead to an increase in CO2 emissions,” says Thomas. The effectiveness of individual projects needs to be much better researched and evaluated. It is also unclear, for example, to what extent international law already obliges states to restore marine habitats. Binding political guidelines are needed. More information: Bryce Van Dam et al, Towards a fair, reliable, and practical verification framework for Blue Carbon-based CDR, Environmental Research Letters (2024). DOI: 10.1088/1748-9326/ad5fa3 Martin Johnson et al, Can coastal and marine carbon dioxide removal help to close the emissions gap? Scientific, legal, economic, and governance considerations, Elem Sci Anth (2024). DOI: 10.1525/elementa.2023.00071 This article is republished from PHYS.ORG and provided by the Helmholtz Association of German Research Centres. Explore our blog for insights on the latest research from across the globe. Click here
Seagrasses are special: they are the only flowering plants that have returned to sea from land. They are also known as the “lungs of the oceans” because of their ability to photosynthesize. And with the exception of Antarctica, they can be found on all continents, where they form extensive underwater meadows that generate and sustain healthy coastal regions. Seagrass meadows are key ecosystem engineers that directly benefit humans and animals. Hence, they are of enormous ecological and economic importance. They are spawning grounds for economically important fish, hiding places for juvenile fish and habitats for mussels, snails and crabs, making them one of the most productive and diverse ecosystems on earth, along with coral reefs and rainforests. They protect our coasts by stabilizing the sediment. They also store carbon dioxide very quickly and effectively. Graphical abstract. Credit: Science of The Total Environment (2023). Seagrass meadows as natural water purifiers A few years ago, another remarkable ecosystem service of seagrasses was discovered: seagrass meadows reduce the load of pathogenic bacteria in the water around them. A 2017 study showed that the relative abundance of harmful bacteria, including human fecal bacteria and pathogens dangerous to marine animals and humans, was significantly (50%) lower in Indonesian seagrass meadows than in the water outside the meadows. Subsequent studies, including one at GEOMAR, have confirmed the reduction of pathogens such as Escherichia coli, enterococci, Salmonella and Vibrio species in the vicinity of seagrass beds. Scientists of the Research Unit Marine Natural Product Chemistry at the GEOMAR Helmholtz Centre for Ocean Research Kiel have been investigating multiple mechanisms behind this sanitation effect for several years. The results of the first part of their study have recently been published in the journal Science of the Total Environment. How do seagrasses combat pathogens? “The elimination of pathogens from the water is a very complex phenomenon involving physical, (micro)biological and chemical mechanisms” says Dr. Deniz Tasdemir, professor of marine natural product chemistry and senior author of the study. The researchers started first analyzing the cultivable microbiome of Zostera marina, a common seagrass species in the Baltic Sea, and the natural molecules they produce. To do this, they isolated almost 90 bacteria and fungi from the surface and internal tissues of the seagrass leaves (and roots) and tested their extracts for antibiotic activity. These tests were carried out against a large group of aquatic, human and plant pathogens, including Vibrio species, which can cause serious diseases and even death when transmitted to humans by raw or undercooked seafood, or through skin damage during recreational activities. This study showed that the bacteria from healthy leaf surfaces have strong, broad-spectrum antibiotic activity, in some cases even outperforming commercial antibiotics. “This confirmed our hypothesis,” says Prof. Tasdemir. In addition to a few known antimicrobial compounds, the team also discovered the presence of many new ones in these bacteria. These new molecules will now be isolated, in other words chemically purified, their chemical structures will be identified and their potential as future marine antibiotics will be assessed. “This is only the tip of the iceberg for us. We now heavily work, with an international team, on other chemical and microbiome-related mechanisms and how they may contribute to the hygiene effect of seagrasses in the laboratory and in the ocean settings,” says Prof. Tasdemir. Antibiotics from the sea: The potential of the seagrass microbiome The climate change-related ocean warming is increasing the load of pathogens, such as Vibrio species, in coastal waters during summer months. This is also a great public health concern for the German Baltic Sea, as death is being reported among holiday makers. Therefore, the protection and restoration of seagrass meadows is essential for the health of oceans and humans more than ever. On the other hand, the seagrass microbiome holds great potential for the discovery of new antibiotics for other human infections, which is of enormous importance in the fight against rising antibiotic resistance. More information: Deniz Tasdemir et al, Epiphytic and endophytic microbiome of the seagrass Zostera marina: Do they contribute to pathogen reduction in seawater?, Science of The Total Environment (2023). DOI: 10.1016/j.scitotenv.2023.168422 This article is republished from PHYS.ORG and provided by the Helmholtz Association of German Research Centres. Explore our blog for insights on the latest research from across the globe. Click here
We have just launched a journal club for the Project Seagrass team. These monthly meetups work much like a book club, members of the team each suggest a relevant scientific paper, vote on their favourite, then read the winning paper prior to meeting. During the journal club we critically discuss the paper and analyse how it relates to our own research. Seagrass science is continually evolving, with researchers across the globe constantly pushing the boundaries of our understanding of how these dynamic ecosystems function and work. This journal club helps us keep abreast of new research, and as it’s held online keeps our team connected across our UK sites. We launched this month with a paper integral to the core values of Project Seagrass: research, community and action. Seagrass meadows globally as a coupled social–ecological system: Implications for human wellbeing, published in 2013 by our CEO, Dr Leanne Cullen-Unsworth and our Chief Scientific Officer, Dr Richard Unsworth, among others. Using this paper to launch Journal club allowed the team to focus on factors influencing the development of Project Seagrass, and to reflect on how our current work aligns with these. The paper describes 7 globally spread case studies highlighting the intricate and dynamic relationship between seagrass and humans, to demonstrate the importance of a social-ecological approach in the field. One reoccurring finding highlights the role of seagrass as a foundation marine species, and nursery ground as vital to subsistence fisheries (fishing for direct community nutrition). Practices such as gleaning (small scale collection of invertebrates from the intertidal using simple gear), and artisanal fin fishing were found key in providing food security and wellbeing for coastal communities, with the highlighted case studies evidencing seagrass decline. The human dependence on seagrass highlights the importance in understanding the associated decline in communities’ capacities for resilience when facing environmental changes. By viewing seagrass meadows as a coupled social-ecological system, projects can carve pathways supporting resilience for both seagrass and people, which in turn support each other. Discussions focussed on a ‘knock before you enter’ approach, and the importance of carrying out stakeholder mapping and social science research to understand complex linkages. This knowledge coupled with ecological site assessments allows conservation and restoration efforts to align with local needs, ensuring social and ecological resilience into the future for seagrass projects. You can access the paper at this link to explore the findings in more depth. Our next journal club meets on the 5th of November, we look forward to sharing the paper and our thoughts on it then. Explore our blog for insights on the latest research from across the globe. Click here
Seagrass meadows play a critical role in keeping our oceans healthy and stocked with food, providing valuable nursery habitat to over 1/5th of the world’s largest 25 fisheries. Seagrass meadows are also important to small-scale fisheries, particularly as a place to find and collect a reliable source of food with some countries (e.g., Indonesia) seeing up to 60% of coastal populations dependant on seagrass for access to food. However, fisheries are more than just sources of food—they are also lifelines for millions of people worldwide, underpinning livelihoods, culture, and well-being. Yet despite their important role, managing these resources, especially in the face of climate change and overfishing, is becoming harder due to a lack of solid data. This is where Indigenous and Local Knowledge (ILK) could support Fisheries Science. A recent study undertaken by Project Seagrass systematically reviewed 397 fisheries-related research articles and revealed that Indigenous and local communities hold key insights into the ecosystems they live in. Indigenous and local communities have often been fishing in their local areas for generations and possess detailed knowledge about species behaviour, habitats, and environmental changes which could fill significant gaps in formal scientific research. The Problem: Gaps Between Indigenous and Local Knowledge and Scientific KnowledgeWhile the scientific community acknowledges the importance of ILK, a large challenge remains: ILK is largely qualitative, based on observations and traditions, whereas fisheries management is based on quantitative data—numbers, charts, and models. Despite efforts to utilise information from scientific knowledge and ILK, the integration has been slow with many studies still viewing ILK as something that needs to be validated through scientific data. The Solution: A New Approach to Fisheries Research The research highlights the need for more collaborative methods to enhance Fisheries Management by integrating ILK and scientific knowledge. Rather than simply comparing Indigenous and Local Knowledge to scientific data, we should view these knowledge systems as complementary. ILK can inform fish population trends, help establish marine protected areas, and guide sustainable fishing practices with a greater chance of success. What’s Next? Moving Towards Integrated Fisheries Management It is crucial to respect both Indigenous and Local Knowledge and scientific knowledge as equally valid. By intertwining these knowledge systems, we can build a more holistic and effective approach to fisheries management, ensuring that the voices of Indigenous and local communities are heard and their knowledge utilized. The next wave of fisheries science should aim to bridge the gap between data-driven science and the rich, qualitative insights from those who know the waters best. The future of sustainable fisheries management depends on it. More information: Jones et al, New directions for Indigenous and local knowledge research and application in fisheries science: Lessons from a systematic review. Fish and Fisheries (2024) DOI: https://doi.org/10.1111/faf.12831 Explore our blog for insights on the latest research from across the globe. Click here
Researchers from the University of Liège (BE) studied the fate of the material produced by Posidonia seagrass meadows. This study, carried out in the Mediterranean Sea at STARESO, shows that the dead leaves of what is commonly known as Neptune grass accumulate in shallow areas, where they break down like a compost, remineralizing the organic matter. This has a previously underestimated effect on carbon fluxes in the Mediterranean coastal environments. Surprisingly, alongside this CO2 emission, oxygen production was also measured. This is linked to the presence of photosynthetic organisms living in this compost in the sea, which fundamentally differentiates it from compost on land. The work is published in the journal Estuarine, Coastal and Shelf Science. From left to right: View of the STARESO harbor entrance with Posidonia meadow islands and an accumulation of dead leaves. Close-up of litter accumulation. Experimental benthic incubation device (‘bell’) installed on accumulations of Posidonia dead leaves (10 m deep). Credit: G.Lepoint & W. Champenois / ULiège Posidonia, a flowering plant emblematic of the Mediterranean Sea, commonly known as Neptune grass, forms vast meadows (underwater prairies) in shallow waters (less than 40m deep). “It is a terrestrial plant that recolonized the marine environment several million years ago, a small quirk of evolution,” explains Alberto Borges, an oceanographer at ULiège. “Like most terrestrial plants in our regions, Posidonia loses its oldest leaves in autumn. These dead leaves accumulate as litter (like at the base of trees) in large patches near the seagrass meadows.” It is these accumulations of dead leaves and their breakdown and transformation that interested the researchers who traveled to STARESO, an underwater and oceanographic research station located in Calvi, Corsica, to conduct a study on the primary production and degradation of organic matter in Posidonia litter. “In the litter, the organic matter breaks down and releases nutrients and CO2, like compost in gardens,” explains Gilles Lepoint. “The litter accumulates in open, sun-light areas.” “Every gardener knows that to grow plants, you need nutrients and light. It is on this basis that we conducted our study which led to a surprising first result: in the litter resulting from the accumulation of material that one would initially imagine as dead and inert, we measured oxygen production, a consequence of the photosynthetic activity of macroalgae drifted from rocks, living Posidonia shoots detached from the nearby meadow, and diatoms (microscopic algae) present in the litter.” To summarize, in this nutrient-rich environment, all living plants associated with the litter thrive and photosynthesize. This oxygen production is significant but does not offset the oxygen consumption by the decomposition of the dead leaves. These accumulations, therefore, remain net consumers of oxygen and, consequently, net emitters of CO2, much like compost and litter in terrestrial environments. The second result from this study somewhat surprised the researchers. “While we thought that Posidonia litter degraded relatively quickly, this study showed us the opposite, based on measurements of litter mass loss—it degrades more slowly,” says Alberto Borges. “We measured respiration through short-term (1-day) incubations based on very precise oxygen measurements.” These measurements provided a more realistic and accurate estimate, with lower values than those traditionally obtained by monitoring mass loss over very long periods (several months). This result could modify the current carbon balance calculations for these ecosystems, which are based on traditional mass loss measurements. As part of this study, the researchers also examined the primary production and degradation of organic matter from the macroalgae growing on rocks adjacent to the Posidonia meadows. “We hypothesized that there might be exchanges between the two systems, which one might initially imagine to be separate and compartmented. Once again, we obtained an unexpected result,” says Willy Champenois. “These macroalgae, despite undergoing photosynthesis, were net consumers of oxygen rather than net producers. This means that the communities of bacteria and invertebrates living within the algae community consume more organic matter than the algae produce. This necessarily implies that this excess organic matter must come from an external source.” By calculating a mass balance, the researchers concluded that this excess organic matter was likely provided by the Posidonia in the form of dissolved organic molecules diffusing from the seagrass meadow and litter to the rocks. In summary, there is a two-way exchange between the macroalgae on the rocks and the Posidonia meadows. The macroalgae drifting from the rocks can accumulate in the Posidonia litter and contribute to primary production there. In turn, the seagrass can supply organic molecules that diffuse to the rocks and are assimilated by the bacterial communities associated with the macroalgae on the rocks. A mutually beneficial relationship, indeed. This study provides new insights into the quantification and understanding of the organic carbon balance of Posidonia seagrass meadows in the Bay of Calvi, which has been the subject of research by oceanographers and marine biologists at the University of Liège since the 1980s, notably through the STARESO marine research station. More information:W. Champenois et al, Community gross primary production and respiration in epilithic macroalgae and Posidonia oceanica macrophytodetritus accumulation in the Bay of Revellata (Corsica), Estuarine, Coastal and Shelf Science (2024). DOI: 10.1016/j.ecss.2024.108971 This article is republished from PHYS.ORG and provided by the University of Liège. Explore our blog for insights on the latest research from across the globe. Click here
