Managing Bivalve Aquaculture to Enhance Blue Carbon Ecosystems and Carbon Sequestration

Plastics in blue carbon ecosystems: a call for global cooperation on climate change goals

Sea-level rise enhances carbon accumulation in United States tidal wetlands

Estimating blue carbon sequestration under coastal management scenarios.

Ocean negative carbon emissions: A new UN Decade program

Coastal blue carbon in China as a nature-based solution toward carbon neutrality

Under the tide of global climate change, achieving carbon neutrality has become a common goal for the international community. The ocean, with its huge carbon storage capacity, has become a key link in the Earth’s carbon cycle. The ocean stores approximately 93% of the Earth’s total carbon dioxide and can remove over 30% of the atmospheric carbon dioxide each year. As the core force of marine carbon sink, blue carbon ecosystem through the high carbon sequestration efficiency of ecosystems such as mangroves, seagrass beds, and coastal salt marshes, plays an irreplaceable role in the global carbon cycle and climate regulation. Meanwhile, although the three-dimensional sea use model has effectively alleviated the industrial sea use contradiction caused by the scarcity of maritime spatial resources, it has also brought the threat of direct damage and indirect functional weakening to the blue carbon ecosystem. At present, there are legal gaps in relevant laws in China. In-depth research on their legal issues is of great significance for protecting the blue carbon ecosystem, promoting marine carbon neutrality and sustainable economic development.

This perspective article synthesises insights from a 2023 interdisciplinary workshop in Kuching, Malaysia, where 26 experts examined how land use and land cover change (LULCC) impacts Blue Carbon Ecosystems (BCE) in Southeast Asia (SEA) and identified pathways for integrated, science-informed governance. BCE in SEA (mangroves, seagrasses and tidal wetlands) are globally significant carbon sinks, critical to biodiversity and the livelihoods of millions, dependant on them for food, income and coastal protection. Yet rapid development and socio-economically driven LULCC threaten BCE resilience and carbon storage capacity. Blue Carbon initiatives risk falling short if they overlook the socio-ecological interconnectivity of these systems. Advances in remote sensing, sediment carbon accounting and ecosystem modelling have improved BCE monitoring, but key gaps persist. These include understanding cumulative upstream effects of LULCC on BCE carbon dynamics, integrating socio-economic with ecological data for robust scenario modelling and evaluating governance effectiveness and equity over time. We frame BCE as dynamic, interconnected socio-ecological systems and call for the advancement of systems thinking in coastal and climate policy. We underscore the need for transdisciplinary, nested governance models operating across ecological scales and political boundaries and argue for a systems-based management approach that links land-sea processes, addresses upstream-downstream dynamics and balances carbon market incentives with local needs. Recommendations include improved monitoring and carbon accounting; alignment between science and policy; regionally coordinated governance; and diversifying finance to reflect the full value of BCE beyond carbon. Together, these actions chart a path for resilient, science-based, socially inclusive BCE conservation in SEA.

In this article, we discuss knowledge and gaps regarding blue carbon ecosystems (BCEs) in Brazil, considering the urgency to apply protection actions and policies to safeguard their biodiversity and associated ecosystem services. We also indicate areas of further research to improve carbon stocks and sequestration rate estimates. We call attention to the shortage of studies on Brazilian BCEs relative to the growing knowledge on the Blue Carbon Framework accumulated worldwide over the last decade. Considering the extensive Brazilian Economic Exclusive Zone (known as “Blue Amazon”), knowledge concerning blue carbon stocks is vital at regional and global scales for mitigating global increases in atmospheric carbon dioxide (CO2). The Blue Amazon has at least 1,100,000 ha of vegetated and non-vegetated coastal ecosystems (mangroves, salt marshes, seagrass meadows, and hypersaline tidal flats) that collectively contain vast amounts of stored carbon, making Brazil an ideal place to test mechanisms for evaluating, conserving, and restoring BCEs. Other poorly understood potential sinks and sources of carbon are macroalgal and rhodolith beds, mudflats, continental shelf sediments, and marine animal forests in shallow, mesophotic, and deep waters. The carbon fluxes between diverse environmental compartments, such as soil–air, soil–water, groundwater–water–surface water, air–water, and land–ocean, in BCEs across the Blue Amazon must be studied. We emphasize the importance of assessing the total carbon stock and the recent dismantling of environmental laws that pose great risks to these important BCEs. The conservation and recovery of these areas would enhance the carbon sequestration capacity of the entire country. Furthermore, we highlight priorities to improve knowledge concerning BCEs and their biogeochemical cycles in the Blue Amazon and to provide information to assist in the reduction of atmospheric levels of CO2 for the United Nations Decade of Ocean Science (2021–2030).

Over the past decade, rapid advances in modelling techniques—from process-based and empirical approaches to ecosystem service tools and risk frameworks—have greatly expanded the ability to quantify the benefits provided by blue carbon ecosystems (mangroves, tidal marshes, and seagrasses), including carbon sequestration, coastal protection, habitat provision, and water quality regulation. However, models vary widely in assumptions, data needs, scales, and documentation, leaving numerous actors (managers, researchers, policy makers) with a confusing number of tools but little guidance on how to choose among them. This gap has major consequences for climate policy and nature based solutions, leading to inconsistent assessments, limited uptake by practitioners, and underuse of robust existing models. Addressing these challenges, we are currently working on a novel project aiming to develop a guideline of the different modelling techniques available to support the quantification of ecosystem services provided by blue carbon ecosystems (e.g., mangroves, tidal marshes, seagrasses). More specifically, we are reviewing the modelling techniques and algorithms available in the scientific literature used to quantify ecosystem services (e.g., coastal protection, resilience, carbon, water quality, etc.) provided by blue carbon ecosystems. We plan to produce a guide to support a variety of actors (e.g., managers, researchers, policy makers, etc.) to apply these models in their work using different case studies. We will develop an online platform that supports coherent, comparable, and policy relevant blue carbon assessments worldwide.

Blue carbon sediments as effective sinks for microplastics: A global meta-analysis.

Blue carbon refers to the considerable amounts of carbon sequestered by mangroves, seagrass beds, tidal marshes and other coastal and marine vegetated ecosystems. At the present time, carbon market mechanisms to compensate those conserving blue carbon ecosystems, and thus reducing carbon emissions, are not yet in place. The ecosystem services provided by coastal vegetated ecosystems extend beyond their carbon storage capacity, and include their contribution to fishery production; shoreline protection; provision of habitat for wildlife and migratory species; flood water attenuation; nutrient cycling, pollution buffering; as well as their cultural, spiritual, subsistence and recreational uses. Because these services are of high economic, social and cultural value, the management and protection of blue carbon ecosystems could build collaboration between climate change and biodiversity practitioners on the national and international level. Such collaboration would also allow for the transfer of lessons learned from coastal management and conservation activities to carbon mitigation projects, and would include the need to work closely together with indigenous peoples and local communities. Resulting management activities on the local level could utilize and strengthen traditional knowledge and management systems related to blue carbon ecosystems, and increase both the resilience of biodiversity and that of coastal communities, as well as provide for long-term storage of blue carbon. While the challenge of scaling up local initiatives remains, some concrete examples already exist, such as the network of locally-managed marine areas (LMMAs) in the Pacific and beyond.

Natural climate solutions are crucial interventions to help countries and companies achieve their net-zero carbon emissions ambitions. Blue carbon ecosystems such as mangroves, seagrasses, and tidal marshes have attracted particular attention for their ability to sequester and store carbon at densities that can far exceed other ecosystems. The science of blue carbon is now clear, and there is substantial interest from companies and individuals who wish to offset greenhouse gas emissions that they cannot otherwise reduce. We characterise the rapid recent rise in interest in blue carbon ecosystems from the corporate sector and highlight the huge scale of demand (potentially $10 billion or more) from companies and investors. We discuss why, despite this interest and demand, the supply of blue carbon credits remains small. Several market-related challenges currently limit the implementation of blue carbon projects and the sale of resulting credits, including the cost and burden of verification of blue carbon compared to verifying carbon credits in other ecosystems, the general small scale of current blue carbon projects, and double counting of credits between commercial and national institutions. To overcome these challenges, we discuss other supplementary financial instruments beyond carbon credit trading that may also be viable to fund the conservation and restoration of coastal habitats, such as bonds and ecosystem service insurance. Ultimately, a portfolio of financial instruments will be needed in order to generate funding streams that are substantial and reliable enough to realise the potential of blue carbon ecosystems as a natural climate solution.

Estuarine marshes, essential and intricate ecosystems, provide crucial services such as carbon sequestration, coastal protection, and habitat support for diverse species. The role of plant-microbe interactions in the carbon cycling and storage of estuarine marshes is pivotal. Despite recent advancements in mechanistic understanding, there remains a research gap regarding the specific impacts of these biotic interactions compared to abiotic factors on carbon cycling within estuarine marsh ecosystems, hindering a comprehensive understanding. Recent studies emphasize the usefulness of process-based models in representing dynamics between plants and microbes in estuarine marshes. Specifically, trait-based models prove instrumental in quantifying the influence of different plant functional types on carbon sequestration rates. While current models often use average trait values to parametrize plant functional types, emerging research suggests that incorporating a range of trait values, reflecting natural variation, could enhance predictive accuracy. To address this, we compare the predictions of a process-based model of soil organic matter decomposition that includes plant type-specific effects using average trait values versus trait ranges. Based on this example, we propose an innovative process-based marsh ecosystem model that explicitly considers the influence of trait variation on complex interactions among plants, soil microbes, and abiotic factors.Our study outlines the systematic evaluation of this model against field observations spanning a salinity and water level gradient in estuarine marshes. The outcomes of this study contribute significantly to advancing our understanding of these dynamic ecosystems, addressing research gaps, and refining the predictive capabilities of ecosystem models in estuarine environments.

The carbon dioxide content in our atmosphere is increasing rapidly. This means that we need better methods to capture and store carbon, and these solutions can work effectively for many years and can be scaled up to a larger scale. Among the various technologies that can be used to reduce carbon emissions, traditional carbon capture and storage methods show promising potential. These methods can reduce carbon emissions by billions of tons every year. However, we need to understand their limitations. These systems require large amounts of energy to operate, and the safety of long term carbon storage remains questionable. In contrast, nature itself offers a powerful solution through the blue carbon ecosystem. Coastal environments such as mangroves, salt marshes, and seagrass meadows have demonstrated extraordinary capabilities in capturing and storing carbon. This work explores how carbon capture systems and natural blue carbon environments can work effectively together. Marine carbon sequestration solutions represented by seabed carbon dioxide storage and Marine alkalization enhancement technologies can achieve the goal of rapid and large-scale carbon removal. Meanwhile, the unique anoxic sedimentary environment and vigorous biological activities in the blue carbon ecological zone jointly enhance the stability of carbon storage, effectively reduces the possibility of leakage, and improves the ecosystem's resilience to environmental pressure. The experimental research results further confirm that in an environment with moderate increased carbon dioxide concentration, the primary productivity of ecosystems such as seagrass beds and mangroves has been significantly enhanced. This discovery provides a new idea for improving the carbon sequestration effect.

Combating climate change requires reducing greenhouse gas (GHG) emissions from human activities and enhancing carbon dioxide removal (CDR) through blue carbon ecosystems (BCEs). Progress is measured by international reporting of national GHG inventories under the UNFCCC, following IPCC guidelines. The EU Green Deal, particularly the EU Biodiversity Strategy to 2030, recognizes BCEs’ potential by advocating for the restoration of carbon-rich habitats. However, the IPCC Wetlands Supplement is underutilized in national GHG reporting, and few countries, especially in Europe, include blue carbon in their Nationally Determined Contributions (NDCs) under the Paris Agreement. This is due to limited awareness, the non-mandatory nature of the IPCC Wetlands Supplement, and data gaps. Our research aims to advance blue carbon knowledge, promoting BCEs as nature-based solutions, and addressing key gaps and scientific uncertainties to improve quantification and reporting of blue carbon under the UNFCCC in GHG inventory reporting under the Paris Agreement. The C-BLUES project, part of the Joint EU-China Flagship Initiative on Climate Change & Biodiversity, seeks to enhance the IPCC Wetlands Supplement, increase BCE inclusion in national GHG inventories, and explore additional BCEs like natural and farmed kelp systems. We document best practices for monitoring and verifying BCE actions, model BCE sequestration capacity, and upscale GHG budgets to estimate BCE contributions to EU and Chinese inventories. We assess carbon stock changes, GHG emissions, and removals from various management interventions, and evaluate the integration of BCEs into national reporting mechanisms. We present a roadmap and invite participation with the scientific community, policy makers and the wider civil society to generate knowledge, raise awareness of BCEs and build capacity for BC research, as well as provide guidance on voluntary reporting on BCE.