Two new studies call for clear frameworks for coastal CO₂ sequestration
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
Bacterial communities on seagrass leaves shown to suppress waterborne pathogens
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