Coastal salt marshes are critical blue carbon sinks but are threatened by coastal reclamation and biological invasion. Conventional discrete mapping lacks temporal continuity, limiting assessments of long-term successional pathways and carbon dynamics. We developed an integrated long-term remote sensing framework using the Landsat archive (1986–2023) to quantify salt marsh dynamics and carbon burial in Hangzhou Bay, China. The framework integrates optimal phenological window selection, continuous change detection, and Random Forest classification to generate accurate annual species-level maps. From 1986 to 2023, salt marshes underwent multi-phase transitions, progressing through natural succession to reclamation-driven coastal squeeze and subsequent invasion-led reorganization. Total wetland area declined by 60%, reflecting the net effect of massive reclamation (893.6 km²) against vegetation expansion. Bare mudflats decreased by 73%, native Scirpus mariqueter by 27%, and invasive Spartina alterniflora expanded by 174%. These transitions led to 49% reduction in annual blue carbon burial (from 71.1 to 36.4 Gg C yr−1). Despite recent invasive expansion and stricter reclamation controls, carbon burial recovery remained limited, reflecting the reclamation’s dominant influence on long-term losses. This study provides a scalable framework for continuous monitoring of salt marsh dynamics and quantifies carbon burial responses to anthropogenic and biological pressures in highly modified estuarine ecosystems.

Comparative analysis of carbon sequestration in salt marsh and bare flat sediments: mechanisms and implications for restoration

BackgroundUnderstanding the vertical distribution and storage of soil organic carbon (SOC) in arid coastal salt marshes is essential for assessing their role in blue-carbon sequestration. This study examines SOC patterns in marshes dominated by Arthrocnemum macrostachyum, Halocnemum strobilaceum, and Salicornia fruticosa, as well as unvegetated areas. Using 200 soil cores (2,000 samples), we applied allometric, exponential, and sigmoid models to predict volumetric SOC density (SOCv; kg C/m³) and cumulative SOC stocks (SOCc; kg C/m²) across depth profiles.ResultsSOC content showed an inverse exponential relationship with soil bulk density across vegetation types, consistent with patterns documented in other salt-marsh and coastal wetland systems. The allometric model provided the best SOCv predictions for A. macrostachyum, whereas the sigmoid model performed best for H. strobilaceum, S. fruticosa, and unvegetated sites, based on mean normalized average error (MNAE), mean normalized bias (MNB), and residual mean squares (RMS). All three models accurately reproduced SOCc for within-core depth extrapolation, with no significant differences between measured and predicted values within the validation dataset.ConclusionsThis study provides an improved understanding of SOC dynamics in arid coastal salt marshes and demonstrates the utility of depth-based mathematical models for predicting SOC storage. These findings support local-scale efforts to evaluate carbon-sequestration potential, though broader spatial validation across heterogeneous landscapes remains necessary.Supplementary InformationThe online version contains supplementary material available at 10.1186/s12870-026-09221-2.

Tracking small-bodied animals in estuarine environments entails significant technological and analytical challenges. Diamond-backed terrapins are small (max 1.4kg) turtles that inhabit salt marshes of the eastern U.S. and the Gulf of Mexico. Terrapin movements have been studied with VHF radio telemetry, acoustic telemetry, and mark and recapture methods, which have indicated maximum straight-line movement distances < 10km and mean home ranges < 1 km2. We deployed 21 Argos satellite tags on adult female terrapins at two sites on Long Island, New York to better understand the spatial ecology of this imperiled species, and to test newly available tracking technology. We processed the location data three ways: (1) we used a location data filter to remove unlikely terrestrial and oceanic locations and applied a state-space model to account for Argos location errors, (2) we applied the state-space model to unfiltered data to determine the effects of not removing unlikely locations, and (3) we used only the highest quality location class 3 (LC 3) locations. We used the data resulting from each of these approaches to calculate four different movement metrics: summer home range size (95% minimum convex polygons (MCPs) and kernel density estimates (50% and 95% KDE, with both reference [href] and least squares cross validation [LSCV] bandwidths)), the total distance traveled from June to August, maximum distance traveled in one day, and daily movement rates. Home ranges estimated from the three processing techniques were similar in size and covered the same spatial areas. Estimates for total distance traveled, daily movement rates, and maximum distance traveled were similar between the state-space modeling techniques, but LC 3 estimated distances were twice as long. Movement metrics and home ranges were similar between the two study sites, despite differences in urbanization and bay size. These results suggest that most movement metrics and home range estimates are fairly insensitive to these different analytical techniques, even at relatively smaller spatial scales. Additionally, our study indicates substantially larger home ranges and longer straight-line movements than VHF telemetry or sonic tag studies, highlighting the utility of satellite tags to improve our understanding of terrapin ecology and conservation.

Vegetation succession enhances soil organic carbon sequestration by modulating microbial carbon cycling genes in coastal marshes, eastern China.

The recent spread of mosquito-borne pathogens and their vectors within Europe highlights the impact of climate change on vector-borne disease (VBD) distributions. Mosquito surveillance has been implemented in many European countries to monitor expansion of vector populations and VBDs, but ability to predict disease risk is constrained by geographic data gaps, particularly in northern areas. In the United Kingdom, wetland mosquito surveillance has been conducted extensively in England, with a knowledge deficit for Scotland. Here, we addressed this gap through a nationwide survey of mosquitoes at Scottish wetlands, with aims of (1) confirming the geographic distribution and environmental drivers of mosquito occurrence and abundance, and (2) identifying the presence of vector species of epidemiological concern, including the Culex pipiens molestus biotype, an important vector of emerging VBDs in mainland Europe. Monthly mosquito sampling was conducted between June and October 2023 at 22 sites across Scotland comprising six wetland types: coastal saltmarsh, wet grassland, wet woodland, reedbeds, ponds and blanket bog. Adult and larval populations were sampled using Biogents BG-Pro traps and larval dipping respectively. Microclimatic and hydrological variables were recorded at collection sites and used in generalised linear mixed models to identify predictors of mosquito presence and abundance. 1951 adults (17 species/groups) and 860 larvae (six species/groups) were collected from wetlands over 183 and 164 sampling events respectively. Mosquitoes were widely distributed across the Scottish mainland including up to the northern coast, being found at all but one site. Several potential vector species including Culex pipiens s.l. and Anopheles claviger s.l. were common. Amongst the adult Culex pipiens s.l. specimens, approximately 8% were Culex pipiens biotype molestus or hybrid forms. Total mosquito abundance and that of key vector species were positively associated with temperature and rainfall. We report the widespread distribution of mosquitoes in wetlands throughout Scotland, including potential vector species previously unconfirmed in Scotland. Predicted associations between mosquito abundance, rainfall and temperature indicate that climate change could favour mosquito populations in Scotland. Our results provide the first detailed description of mosquito ecology in Scotland, as required to update assessment of VBD risk under climate change.LE: Graphical abstract is mandatory for publication in this journal. Please provide the graphical abstract.Thank you, this will be uploaded and attached.

Competitive interactions between invasive Phragmites australis and Spartina alterniflora: Mechanisms and management implications for marsh migration

• Ecosystem services emerge from the exchange of exported biomass across connected coastal systems. • Ecosystem services provided by exported marine macrophyte biomass (EMB) are substantial but often overlooked. • Temporal, spatial, and environmental factors interact with exported biomass attributes to drive service provisioning. • EMB should be included in ecosystem service frameworks to improve coastal management. • More work is needed to determine how to account for EMB in ecosystem service valuations. As societies increasingly aim to quantify and preserve nature’s benefits, ecosystem services provided by marine ecosystems are increasingly evaluated. However, these evaluations commonly focus on single ecosystems, despite the growing evidence that ecosystems interact. Here, we investigated the ecosystem services provided by macroscopic exported macrophyte biomass (EMB) from seagrass meadows, salt marshes, mangrove forests, and macroalgae forests using a systematic literature review of EMB in marine settings. We found that vegetative biomass exported from marine macrophytes substantially contributed to the provisioning of ecosystem services in recipient ecosystems – habitat provisioning, carbon storage, nutrient cycling, and abiotic alterations, among others – but were rarely documented as such. We identified time since deposition, proximity to donor ecosystem, EMB magnitude, and EMB seasonality as drivers of ecosystem service outcomes. Knowledge gaps related to EMB ecosystem services suggest that more research is needed across 1) vegetated recipient ecosystems, 2) ecosystem service types, 3) contexts in which EMB provides ecosystem services or disservices, 4) potential management strategies, and 5) regions of the world. We call for broader consideration of the contributions of EMB to ecosystem services within ecosystem services frameworks to increase the accuracy of global valuations and enhance strategies for conserving, restoring, and managing marine ecosystems.

Sediment physicochemical and dissolved organic matter control microbial responses and nitrous oxide emissions across a coastal wetland transition from invasion to reclamation.

Salt marsh establishment controlled by sediment availability, landscape position, and anthropogenic history

Linking biomechanical stem properties of salt marsh vegetation to flow field alterations: A regional and seasonal analysis

The coexistence of multiple salt marsh vegetation types significantly constrains classification accuracy in coastal wetlands. Due to the pronounced seasonality of salt marsh vegetation, SAR imagery offers continuous data support for the entire growing season. Different vegetation types demonstrate distinct coherence and backscattering characteristics in SAR imagery, which traditional classification approaches struggle to exploit effectively. To address this limitation, we took the Yellow River Delta (YRD) Wetland in China as the study area, used 30 Sentinel-1A images acquired in 2018 as the data source, extracted multi-temporal baseline coherence features and combined them with backscattering features. RF, XGBoost, and LightGBM were employed to investigate the accuracy improvements achieved by introducing multi-temporal baseline coherence. Results demonstrated that incorporating multi-temporal baseline coherence improved the OA of RF by 3.68%, 4.89%, and 2.10%; XGBoost by 3.75%, 4.19%, and 3.05%; and LightGBM by 4.07%, 3.36%, and 1.59% under VH, VV, and VH+VV polarizations, respectively. The optimal scheme achieved an OA of 92.51%. SHAP analysis revealed that coherence features derived between January and May contributed most significantly to the discrimination of salt marshs compared with those derived from short temporal baselines. The proposed approach provides a technical reference for the coastal wetland classification using SAR imagery.

ABSTRACT Inland salt marshes have high carbon sequestration capacity but are highly vulnerable to land-use change. Afforestation is a biological assisted restoration strategy to mitigate wetland degradation, significantly impacting soil organic carbon and enzyme activity. However, the mechanisms underlying these effects remain unclear. This study investigated Tamarix chinensis plantations of different stand ages (3, 7, and 11 years) and adjacent secondary bare land (control) to examine the responses of labile organic carbon fractions and soil enzyme activities to stand age. The results showed that soil organic carbon and total nitrogen content gradually increased with stand age, while soil pH and electrical conductivity initially decreased and then increased with stand age. Compared to the control, the early stages of Tamarix chinensis establishment generally enhanced the content of three labile organic carbon fractions. Urease and peroxidase activities exhibited a continuous increase with plantation age. Conversely, sucrase and alkaline phosphatase activities peaked in the 7-year-old plantation and then declined gradually. Redundancy analysis identified electrical conductivity as the main driver of labile organic carbon variation, while both pH and electrical conductivity were key factors influencing enzyme activities. This study provides scientific references for the restoration and sustainable management of inland salt marshes in China.

Biodegradable facilitation mimics extend the window of opportunity for salt marsh establishment.

Wetland ecosystems play important ecological functions but remain the least studied habitats for arbuscular mycorrhizal fungi (AMF) compared to terrestrial ecosystems. Prior studies were often conducted in a small spatial area and focused only on a single wetland type, limiting our understanding of wetland communities in large-scale wetlands. To address this gap, we conducted a meta-analysis of 380 wetland samples from the wetland habitat, targeting the 18S rDNA region, focusing on high-throughput sequencing (HTS) data. In this study, we deliver large-scale dataset syntheses of AMF across multiple wetland types using a standardized pipeline. We categorized wetlands into inland wetlands (freshwater wetland and rice farm) and coastal wetlands (mangrove forest and salt marsh). This meta-analysis study revealed clear differences in AMF richness between inland and coastal wetlands. AMF richness was significantly higher in inland wetlands (freshwater and rice ecosystems) than in coastal wetlands (mangrove and salt marsh), with mangroves showing the lowest richness among all habitats. Habitat explained broader variation, whereas sample type showed a smaller but more consistent effect. Moreover, soil pH showed a positive correlation (R = 0.18, p = 0.00043), while mean annual precipitation (MAP) (R= –0.42, p <2.2 × 10−16) and mean annual temperature (MAT) (R = -0.35, p = 1.1 × 10−12) were negatively correlated with richness. Beta diversity analysis indicated that species turnover was more dominant than nestedness across different wetland types. Overall, AMF communities in wetlands are associated with soil pH and climate (MAP), with differences mainly driven by species turnover. The insight from this study reveals that mangrove wetlands are hosts to unique AMF diversity pools, despite low local richness. Moreover, this this study provides insights into mechanisms that may contribute to ecosystem resilience.

The leaf endosphere hosts diazotrophs vital for plant health and ecosystem resilience in saline environments. However, the geographic pattern and stability of the diazotrophic community in coastal salt marshes ecosystems are poorly understood. In this study, we examine the biogeographic distribution, assembly processes and community stability of leaf endophytic diazotrophs in the mangrove species Kandelia obovata across multiple regions in China. Our findings reveal that Rhizobiales are the most abundant in the diazotrophic communities. Community assembly is largely governed by stochastic processes, with dispersal limitations playing a dominant role. Soil nutrients emerge as the dominant factor influencing diazotroph composition, surpassing climatic variables and host traits. Notably, soil total sulfur (TS) serves as a key environmental factor shaping the diazotrophic community structure, with low TS environments supporting more stable microbial networks. These findings reveal ecological drivers and adaption strategies of endophytic diazotrophic communities in mangrove ecosystems, emphasizing the influence of nutrients dynamics in leaf endophytic microbial assembly under environmental changes.

Coastal ecosystems are increasingly recognized as a crucial nature-based climate solution due to their remarkable capacity for carbon sequestration. However, the spatial distribution and quantification of soil organic carbon accumulation rate (OCAR) at the global scale remain limited. Here, we assemble an open global dataset of soil OCAR in coastal ecosystems from a systematic literature review. The dataset comprises 8,998 field observations from 247 peer-reviewed articles, encompassing four distinct ecosystem types (mangroves, salt marshes, seagrasses, and tidal flats). Furthermore, the dataset includes publication details of the source articles, geographical and ecological attributes of the sampling sites, and information for each observation. The dataset can be employed to more precisely quantify and map global coastal soil carbon sequestration capacity, enabling the development of global spatiotemporal prediction models. This dataset serves as a vital scientific foundation for informing management strategies of coastal ecosystems and guiding future carbon credit markets.

Against the backdrop of intensifying global climate change, reducing carbon emissions has become a shared global objective. Blue carbon, as a significant carbon sink type, still lacks a mature assessment framework. Monitoring carbon fluxes in marine salt marsh wetlands is a core technology for accurately evaluating blue carbon potential. In response, this study independently developed a spatiotemporally coupled carbon flux monitoring system for marine salt marsh wetlands. The system consists of real-time monitoring equipment, a cloud-based intelligent storage and visualization analysis platform, and a terminal assessment system. It enables the real-time monitoring of carbon fluxes across multiple spatial scales and integrates time-series patterns to assess carbon sequestration potential from multiple dimensions. To address the bottleneck of sensor accuracy, a multi-algorithm fusion technology was innovatively developed, significantly enhancing the accuracy of monitoring data. A modular integrated design was employed to construct a land–air integrated monitoring architecture, which is adaptable to the complex environments of salt marsh wetlands. This facilitates long-term automated monitoring while reducing the need for manual intervention. The terminal assessment system processes spatial-scale data using the DeNitrification-DeComposition model (DNDC 9.5) and integrates time-series carbon flux patterns, enabling precise quantification of marine carbon sink potential through spatiotemporal comprehensive analysis. The system first completed performance verification during the experimental phase, acquiring a total of 5760 sets of valid monitoring data, with a data qualification rate of 99.72%. The proposed multi-algorithm fusion method kept monitoring data fluctuations within 0.5%, and the relative error of the spatiotemporal integrated prediction was as low as 0.31%, thereby ensuring the stability and accuracy of long-term in situ monitoring. Based on this, a one-year field validation was conducted in a 100-hectare coastal salt marsh wetland in Dafeng, Yancheng. Using a spatiotemporal coupling assessment, the annual total carbon sequestration of this area was estimated at 1498.4 tons of carbon, with an assessment error of only 5.1%, achieving precise quantification of the blue carbon sink in the salt marsh wetland. This study provides reliable technical support for evaluating the carbon sequestration capacity of coastal salt marsh wetlands, contributing to the implementation of carbon emission reduction strategies. It also offers a scientific basis for global carbon cycle research and carbon sink management decision-making.

ABSTRACT Salt marsh soils store substantial organic carbon, yet the persistence of this carbon depends on microbial community composition that governs key transformation processes. Coastal reclamation buries former marshes, but how burial alters microbiomes and carbon‐relevant functions through time remains unclear. We investigated successional shifts in soil microbiomes across a reclamation chronosequence in the Yangtze River Estuary and compared buried (historically reclaimed) soils with modern marsh soils using 16S rRNA high‐throughput sequencing. Bacterial diversity declined significantly in buried soils, with Shannon index values decreasing from 7.07–7.24 in modern soils to 6.13–6.55, accompanied by a depth‐related shift from aerobic to anaerobic dominance. Burial duration was the strongest predictor of community composition ( r 2 = 0.6759, p = 0.001), indicating that prolonged burial after reclamation is associated with physicochemical changes that restructure microbiomes. Total organic carbon, total nitrogen, and pH were the main environmental correlates; total organic carbon decreased with depth, consistent with the expansion of anaerobes and intensified carbon and sulfur cycling. Redundancy analysis showed that variation in these soil properties explained 56.61% of community differences. By linking burial‐driven microbial reassembly to measurable soil properties, these findings elucidate the spatiotemporal dynamics of microbial communities in buried salt marshes induced by reclamation and their environmental constraints, providing a theoretical basis for assessing the stability of soil carbon sinks of salt marshes.

• Sequential δ 13 C and δ 18 O analyses of dental enamel provided evidence of cattle feeding habits from Mas Castellar de Pontós. • Data confirm the integration of C 4 plants into the cattle diet during the warmer months. • Two possible options are proposed: the consumption of cultivated cereals or of wild plants from the coast and salt marshes. • Cattle, as well as sheep, had access to a diversified range of plant resources during the year. • The results suggest the adoption of a deliberate and adaptive seasonal livestock feeding strategy. This study investigates cattle feeding strategies at the Late Iron Age rural establishment of Mas Castellar de Pontós (Empordà plain, northeastern Iberian Peninsula), a key agricultural and commercial centre linked to the coastal Greek colonies of Emporion and Rhode. Previous isotopic data from bulk collagen analyses of bones (Messana et al. 2025) suggested a potential introduction of C 4 plants into the cattle diet; however, the temporal dimensions of this practice remained unclear. To address this gap, sequential analyses of δ 13 C and δ 18 O values were performed on dental enamel from seven lower molars belonging to five cattle, allowing a seasonal resolution of their feeding habits. The results confirm the seasonal integration of C 4 plants into the cattle diet during the warmer months, complementing a basal C 3 plant consumption during the year. Considering the landscape surrounding the settlement and the agricultural activity, two options are proposed regarding the nature of the C 4 plants consumed: cultivated cereals such as millet or wild plants growing along the coast and in salt marshes. The isotopic data currently available do not allow a discernment between the two hypotheses, resulting in a scenario of so-called equifinality. This pattern reflects a deliberate and seasonally adaptive feeding strategy, comparable to that observed in sheep from the same settlement. This evidence suggest that cattle, as has been documented for sheep, had access to a diversified range of plant resources during the year. These livestock feeding habits may have been adopted by herders to maximise the availability of pasture and/or fodder.