Mangrove forests (MFs) play a crucial role in climate change mitigation due to their capacity to store significant amounts of blue carbon. This study investigates carbon sequestration dynamics in MF sediments, encompassing natural stands (sites BD1 and BD3) and planted stands (sites PN2, PN3, and PN4), focusing on vertical soil profiles up to 1m depth. Results indicate that natural mangroves function as blue carbon hotspots, benefiting from mangrove, terrestrial, and marine organic matter (OM) inputs. In comparison, a 10-year-old plantation (PN2) stored approximately twice the carbon of a 2-year-old plantation (PN4), suggesting that effective carbon sink development requires more than a decade. Sediment cores revealed that BD1 dates back to 1952, whereas PN2 is older, dating to 1919. Fine sand layers at BD3 and PN4 are likely remnants of tropical storm deposits, illustrating how mangroves archive century-scale hydroclimatic events. Microplastic (MP) pollution is emerging as a critical concern, with both natural and planted mangroves accumulating MPs in their sediments. A negative correlation between MPs and total organic carbon (TOC) in natural forests suggests that organic-rich sediments may reduce MP retention through competitive adsorption or enhanced biodegradation-an unprecedented finding requiring further investigation. Overall, this study underscores the importance of mangrove restoration for climate resilience and highlights the necessity of integrating MP pollution into blue carbon management strategies. It advances understanding of plantation effectiveness, sediment carbon stability, and anthropogenic stressors influencing mangrove ecosystems.

Spatial variability in the carbon stocks of different seagrass meadows of southern Palk Bay, India: Influence of species composition, sediment characteristics and restoration efforts.

Understanding where blue carbon habitats occur and how they are affected by human activity contributes to effective management of natural carbon sinks. Here, we compiled geographical data for Sweden to map the distribution of coastal vegetated blue carbon (BC) habitats. The mapping effort focused on well-recognised (salt marshes and seagrass meadows) and emergent BC habitats (other rooted submerged macrophytes and forested wetlands). We also estimated the exposure to anthropogenic pressures on coastal BC habitats based on their proximity to land-based human activities, and subsequently, the portion of these BC habitats that were located within protected areas. The total area of BC habitats was estimated to around 1850 km2, corresponding to ca. 35% of the Swedish coast. Seagrass meadows and other rooted submerged macrophytes were dominating, covering about 1500 km2. Around 22% of the mapped BC habitats were expected to be exposed to high pressures from land-based human activities due to their location, while BC habitats within protected areas were often less exposed. This nationwide assessment of coastal vegetated BC habitats accentuates the need for strengthening conservation prioritisation to maximise the carbon storage potential of BC habitats.

Sentinel node technologies in low-resource settings: Current evidence and future perspectives.

Bifunctional exploration of Corydalis-derived blue fluorescent carbon dots: From high-sensitivity chlortetracycline detection to flexible fluorescent membranes

Dynamics of leaf litter decomposition and nutrient release in mangroves under different control conditions: Highlighting the litter quality, decomposer and mixing effect.

Blue carbon, introduced by the United Nations Environment Programme in 2009, has gained global attention as a promising strategy for mitigating climate change. This paper examines how Japanese television and newspapers convey blue carbon, focusing on their role in shaping scientific concepts within marine governance. Through a content analysis of 29 television programs and 26 newspaper articles published between March 2023 and August 2024, the study evaluates each coverage against five expert-defined criteria, including the explanation of blue carbon mechanisms, current conditions of marie ecosystems, and associated risks and challenges. Results reveal that Japanese television and newspapers insufficiently address scientific explanations of blue carbon, such as presenting potential challenges and risks, or appropriate use of quantitative data for public understanding. Furthermore, biases considered specific to Japan were also identified. This lack of depth or biases may limit the effectiveness of public communication in fostering an accurate and comprehensive understanding of blue carbon. Thus, this study highlights the importance of presenting balanced narratives that incorporate both the benefits and challenges of blue carbon initiatives. Additionally, the findings emphasize the critical need for enhanced understanding and collaboration among media professionals, policymakers, marine scientists to ensure the development of effective communication strategies. Such approaches can not only improve public awareness but also facilitate the adoption of informed policies. By bridging gaps between expert knowledge and public discourse, this research contributes to the advancement of science-based marine policy in Japan and provides a model for other countries.

Delivering the ocean climate actions: Building a robust information base to facilitate and enhance the incorporation of blue carbon solutions into Kenya’s climate commitments

Decadal change (2015-2025) in seagrass cover, species composition and ecosystem quality in eastern Bintan marine protected area, Indonesia.

Saltmarshes provide key ecosystem services, including atmospheric CO2 sequestration and nitrogen burial in sediments. In recent decades, these blue carbon ecosystems have faced significant degradation from natural and anthropogenic stressors. In this study, rewilding of a desiccated saltmarsh in Cadiz Bay (SW Spain) was assessed as a nature-based solution to restore carbon (Corg) and nitrogen (NT) storage. The rewilding process began in 2004 after breaching an external tidal wall. We evaluated changes in vegetated and unvegetated areas using Landsat satellite imagery (1994-2024) and quantified Corg and NT stocks and burial rates in wild and rewilded sediments, including vegetated saltmarsh (Sarcocornia sp.) and bare sediments colonized by microphytobenthos (MPB). Vegetated saltmarsh cover increased by 85% over 20 years, at an average recovery rate of 5hay-1, concurrent with a decrease in unvegetated tidal flats. Average Corg stocks in the top 1m ranged from 32 to 57t Corg ha-1, with higher values in vegetated sediments. However, only 5-12% of Corg was stored during the rewilding period. Corg burial rates averaged 69g Corg m-2 y-1, and NT stocks were 55% higher in rewilded sediments than in wild ones (3.6 vs. 1.6t NT ha-1). Despite vegetation recovery, burial rates of Corg and NT did not increase clearly, suggesting that long-term storage may be influenced by factors beyond rewilding. Less than 8% of sedimentary Corg originated from saltmarsh vegetation, indicating the dominance of allochthonous sources. These findings highlight the complexity of biogeochemical recovery in rewilded saltmarshes and underscore the need for long-term monitoring to determine how much time is truly required for Corg and NT recovery.

We provide information about the accumulation of microplastic and other anthropogenic microparticles (AMP) in tidal blue carbon ecosystems from Eastern Brazil. This study analyzed the accumulation of AMP in 40 sediment samples extracted from tropical Spartina marsh (2 cores: CM1 and CM2) and mangrove (1 core: CAB) from Todos os Santos Bay (TSB, Bahia, Brazil). The main objective was to identify differences in AMP accumulation between mangrove and Spartina salt marsh cores in order to understand their different roles in AMP retention; and evaluate if Spartina marshes act as stronger AMP sinks than mangroves. The average AMP abundance was at least 38% higher in saltmarshes compared to mangroves. Micro-Raman spectroscopy was applied to determine the chemical composition of the different collected samples, thereby enabling a detailed investigation of their structural and compositional features. Fibers represent the dominant category, likely due to the large widespread use of synthetic fibers, insufficient wastewater treatment and high levels of fishing activities in the area. The predominant color in all cores is blue (41.6%) and transparent (20.0%), the predominant particle size in all cores is between 0 and 1mm. Organic matter (%OM) and mud content (%M) did not influence AMP concentration. This work improves the understanding of the distribution and consequences of AMP in South American mangrove and salt marsh ecosystems, highlighting the need for collective, comprehensive efforts to mitigate their effects, such as improving the efficiency of wastewater management and other human uses and mismanagement in TSB.

Extreme drought drives contrasting fates of labile and recalcitrant mangrove soil organic matter.

Evaluating the effectiveness of marine ecological restoration in Xiamen Bay: A three-dimensional ecosystem-based framework.

Aiming at the problem of simultaneous monitoring of chlortetracycline (CTC) and lead ions (Pb2+) in food and the environment, high-performance nitrogen/sulfur co-doped blue fluorescent carbon dots (NS-CDs) were successfully synthesized by a one-step solvothermal method using oxalic acid and 1-amino-2-naphthol-4-sulfonic acid as precursors. The NS-CDs have a high quantum yield of 39.5% and excellent photostability. Based on the efficient quenching of NS-CD fluorescence by CTC and Pb2+, a dual-functional fluorescence sensing platform for simultaneous detection of CTC and Pb2+ was constructed for the first time. Under the optimized conditions, the linear detection ranges for CTC and Pb2+ were 0-35 µM (R2 = 0.9911) and 0-5.4 µM (R2 = 0.9948), respectively, and the detection limits were as low as 2.32 µM and 0.22 µM, respectively. The probe was successfully applied to the analysis of real river water samples. The recoveries of CTC and Pb2+ were 92.4-101.5% and 92-98.3% (RSD < 4%), respectively. This work provides a novel, simple and low-cost solution for the rapid and integrated on-site detection of multi-class pollutants in complex matrices.

Coastal salt marshes store substantial organic carbon, but strong heterogeneity in carbon density complicates upscaling for blue carbon accounting, national inventories, and restoration planning. Using a standardized monitoring dataset from 361 salt marsh sites across eight coastal provinces in China (2021–2024), we quantified sediment carbon density in the upper 0–1 m and biomass carbon density (aboveground and belowground), and evaluated plausible drivers. Carbon densities were highly skewed, with sediment carbon dominating the combined carbon density. Vegetation composition explained the strongest contrasts: Spartina spp.-dominated marshes exhibited higher sediment and combined carbon density than Phragmites spp. and Bulrush/Sedge (mixed Cyperaceae taxa; including Schoenoplectus spp., Bolboschoenoplectus spp., and Carex spp.) marshes, whereas Phragmites spp. marshes supported the highest total biomass carbon density. After adjustment for vegetation group, sampling year, and latitude, sediment carbon density showed a modest negative latitudinal trend. Sediment fine fraction had little marginal association with sediment carbon density, but emerged as a positive predictor of sediment and combined carbon density once geographic and compositional structure was accounted for, consistent with context-dependent texture effects. In contrast, total biomass carbon density showed limited covariate-adjusted association with either fine fraction or sediment carbon density, and biomass allocation metrics did not provide a direct proxy for sediment carbon density. These results support stratified monitoring, reporting and verification designs that use vegetation group as a first-order stratum and sediment texture as a secondary modifier to strengthen higher-tier, accounting-relevant reporting and restoration targeting.

Public awareness of coastal blue carbon ecosystems (CBCE): An essential piece for enhancing ocean literacy in Taiwan

Blue carbon ecosystems, including mangroves, offer nature-based solutions against the impacts of climate change. Degraded coastal agricultural lands that were previously coastal wetlands harbour ancient (>1,000 years) soil organic carbon (SOC) pools and can be potential candidates for coastal wetland restoration. We investigated the SOC storage capacity of coastal wetlands under rehabilitation (CWUR) by measuring the SOC stocks of coastal wetlands under different stages of rehabilitation (Phase 1 and Phase 2 sites) and comparing their stocks to those from well-established mature mangroves (reference sites). The location of our study is on Maroochy River floodplain on the Sunshine Coast, Queensland, Australia. In addition, the contribution of different sources to SOC in mature mangroves and CWUR was investigated using Bayesian stable isotope mixing models. Dating of sediments by 210Pb and 137Cs radionuclides was used to estimate the historical sedimentation and carbon accumulation rates for mature mangroves. CWUR had SOC stocks ranged from 242.6 to 322.2 Mg OC ha-1 m-1 whereas the average SOC stocks of mature mangroves were 461.4 Mg OC ha-1 m-1. Not only are the carbon stocks in mature mangroves higher than those for CWUR but they are also comparable to those from mangroves in subtropical Australia and estuarine settings. Unexpectedly, CWUR had higher SOC stocks compared to SOC stocks for pasturelands from previous studies. The suspended particulate matter (SPM) supplied by tidal and fluvial processes is a main constituent of SOC pools in both mature mangroves and CWUR that we studied. Furthermore, mangrove roots contributed significantly to peat and organic-rich sediment formation in mature mangroves on Maroochy River floodplain. Presence of remnant SOC (>1000 years) and availability of accommodation space for sediment deposition in CWUR are advantageous for blue carbon restoration.

Understanding the resilience of Halophila ovalis to warming and nutrient enrichment for improved seagrass conservation policy.

Mangrove biomass and carbon storage in India: Implications for blue carbon potential

Coastal wetlands, such as salt marsh and seagrass beds, are important sedimentary carbon sinks attributed to their inherent sequestration proficiencies. Their spatial heterogeneity however, introduces uncertainties in sediment blue carbon assessments, requiring explanatory understanding of causal factors, particularly where environmental gradients are evident. This study measured the spatial variability in sediment carbon stocks associated with seagrass, salt marsh, and degraded (disturbed, unvegetated sites) habitats, identifying causal geochemical factors. Significant intra-habitat sediment carbon partitioning was observed (mean SE), where degraded habitats (83.63 9.67 Mg C ha -1 ) and supratidal Salicornia pillansii marsh (65.36 8.62 Mg C ha -1 ) had significantly lower carbon stocks than intertidal salt marsh, Spartina maritima (203.25 35.03 Mg C ha -1 ) and Salicornia tegetaria (243.58 67.84 Mg C ha -1 ), as well as seagrass Zostera capensis (211.4 20.12 Mg C ha -1 ). At the estuary scale statistical correlations were found between sedimentary stocks and several explanatory biogeochemical factors including sediment bulk density (SDB, p < 0.01), particle size ( p < 0.05), total organic matter ( p < 0.001), and salinity ( p < 0.05). Furthermore, a significant inverse association was found between sediment carbon stocks and landward oceanic distance – stressing the effect of geomorphic setting on net estuarine sedimentary carbon accretion. By interpolating the spatial variability in sediment carbon stocks, this study identified opportunities for enhancing salt marsh carbon stock through restoration (385.4ha). The potential carbon emissions, attributed to possible degradation and loss of all habitats from the Swartkops Estuary, was predicted to be 2962.51 Mg CO 2 e ha -1 yr -1 . This further highlights the value of extant carbon stocks, opportunities for restoration of disturbed habitats, and the implications for potential carbon emissions from blue carbon habitats. Furthermore, it reinforces the importance of accounting for local carbon stock variability for blue carbon restoration and/or conservation actions. • Percentage organic carbon partitioned by habitats identified blue carbon hotspots. • Organic carbon decreased landwards and was greater in intertidal marshes. • Carbon stocks were positively correlated with finer grain sediments. • Percentage organic carbon showed strong inter-habitat and spatial heterogeneity. • Salt marsh disproportionately contributes to carbon storage in semi-arid estuaries.