Search Results (218)

Invasive plant species pose an increasing threat to mangroves globally. This study assessed the impact of Paspalum vaginatum invasion on carbon loss and early recovery following four years of restoration in a mangrove forest with Rhizophora racemosa in Benin. Organic carbon was quantified in the total biomass, including both aboveground and belowground components, as well as in the soil to a depth of −50 cm. In addition, soil gas fluxes of CO₂, CH₄, and N₂O were measured. Three sites were evaluated: a conserved mangrove, a site degraded by P. vaginatum, and the same site post-restoration via hydrological rehabilitation and reforestation. Invasion significantly reduced carbon storage, especially in soil, due to lower biomass, incorporation of low C/N ratio organic residues, and compaction. Restoration recovered 7.8% of the total biomass carbon compared to the conserved mangrove site, although soil organic carbon did not rise significantly in the short term. However, improvements in deep soil C/N ratios (15–30 and 30–50 cm) suggest enhanced soil organic matter recalcitrance linked to R. racemosa reforestation. Soil CO₂ emissions dropped by 60% at the restored site, underscoring restoration’s potential to mitigate early carbon loss. These results highlight the need to control invasive species and suggest that restoration can generate additional social benefits. Full article

Typhoons are major climate disturbances that significantly impact coastal ecosystems, particularly mangrove forests. This study examines the effects of typhoons on mangrove communities at different stages of recovery, focusing on how environmental factors influence carbon storage and net ecosystem exchange (NEE). Three mangrove sites were selected based on their recovery age: young, moderately restored, and mature. The results revealed that typhoons had the most pronounced effect on young mangroves, resulting in significant reductions in both above-ground and soil carbon storage. In contrast, mid-aged and mature mangroves demonstrated greater resilience, with mature mangroves recovering most rapidly in terms of community structure and carbon storage. Key factors such as wind speed, heavy rainfall, and changes in photosynthetically active radiation (PAR) contributed to carbon storage losses, particularly in young mangrove forests. This study underscores the importance of recovery age in determining mangrove resilience to extreme weather events and offers insights for enhancing restoration and conservation strategies to mitigate the impacts of climate change on coastal carbon sequestration. Full article

The focus of this study was on young populations of Kandelia obovata within a constructed coastal wetland in Haicang Bay, Xiamen, Southeast China. The objective was to systematically examine their allometric growth characteristics and carbon sequestration potential over an 8-year monitoring period (2016–2024). Allometric equations were developed to estimate biomass, and the spatiotemporal variation in both plant and soil carbon stocks was estimated. There was a significant increase in total biomass per tree, from 120 ± 17 g at initial planting to 4.37 ± 0.59 kg after 8 years (p < 0.001), with aboveground biomass accounting for the largest part (72.2% ± 7.3%). The power law equation with D²H as an independent variable yielded the highest predictive accuracy for total biomass (R² = 0.957). Vegetation carbon storage exhibited an annual growth rate of 4.2 ± 0.8 Mg C·ha⁻¹·yr⁻¹. In contrast, sediment carbon stocks did not show a significant increase throughout the experimental period, although long-term accumulation was observed. The restoration of mangroves in urban coastal constructed wetlands is an effective measure to sequester carbon, achieving a carbon accumulation rate of 21.8 Mg CO₂eq·ha⁻¹·yr⁻¹. This rate surpasses that of traditional restoration methods, underscoring the pivotal role of interventions in augmenting blue carbon sinks. This study provides essential parameters for allometric modeling and carbon accounting in urban mangrove afforestation strategies, facilitating optimized restoration management and low-carbon strategies. Full article

Hopanoids are a series of important lipid biomarkers in the bacterial cellular membranes that are found ubiquitously in different spatial and temporal environments. Squalene-hopane cyclase, a key and prerequisite molecular component of the hopanoid biosynthesis pathway, is encoded by the sqhC gene. To investigate the composition, niche, and distribution of microbial sqhC-containing communities, we analyzed hopanoid producer data and environmental parameters across different ecosystems on the basis of sequencing reads of peat samples from increasing gradient depths across peatland profile C in the Dajiuhu Peatland, as well as data collected from available published papers. The results indicated that the acidic Dajiuhu Peatland harbored mainly Acidobacteria (59.16%) among its sqhC-containing groups. The main composition of hopanoid producers in the peatland was different from that in other ecosystems, with Alphaproteobacteria found in soil (37.78%), cave (48.21%), hypersaline lagoon (34.04%), and marine (32.59%) ecosystems; Betaproteobacteria, Gammaproteobacteria, and Deltaproteobacteria found in reef (100%), acid mine drainage (55.00%), and estuary, mangrove, and harbor (39.66%) ecosystems; and an unknown cluster found in freshwater (29.43%) and hot spring (89.58%) ecosystems. Compared with other phyla or sub-phyla, Alphaproteobacteria, Betaproteobacteria, and Gammaproteobacteria were the most widespread, occurring in eight ecosystems. Peatland was significantly separated from the other nine ecosystem modules in the occurrence network, and the marine ecosystem had the greatest impact on the eco-network of sqhC microbes. An RDA indicated that pH, DO, salinity, and TOC had significant impacts on sqhC-containing microbial communities across the different ecosystems. Our results will be helpful to understanding the diversity, composition, and distribution of the sqhC community and its response to multiple environmental factors across different ecosystems. Full article

Carbonat—open-water mangroves have high organic carbon (OC) content, apparently due to sediments’ biophysical characteristics. However, the role of key regulators such as salinity and hydroperiod, which modulate the forest structure and, therefore, carbon dynamics, has been little explored. This study evaluates the influence of salinity on the accumulation of aerial and underground OC (production of litter and roots), in open—water karstic forests. To this end, an experimental design was implemented on San Andrés Island, where an edaphic salinity gradient exists due to the water regime. Three physiographic types of mangroves, characterized by different saline regimes, were selected for the study. Two inland forests were selected, both of which exhibited a mesohaline regime (9.63 ± 6.26 and 11.54 ± 7.46 PSU), while a third site corresponded to a euhaline fringe forest (37.47 ± 5.76 PSU). The final location was characterized by a hyperhaline regime basin forest (62.36 ± 10.54 PSU). The fundamental hypothesis posited an inverse relationship between salinity and litter production, and a direct relationship between salinity and root production. To assess root production, the growth core implantation technique (108 soil cores) was employed, with live roots selected based on diameter (<2, 2–5, and 5–20 mm). The mean (±SD) OC content in dry litter ($\mathrm{M}\mathrm{g} \mathrm{C} {\mathrm{h}\mathrm{a}}^{-1}{\mathrm{y}}^{-1}$) was 8.96 ± 0.28; 5.57 ± 0.15; 6.31 ± 0.27; and 4.54 ± 0.8; while The production of dry roots was 0.41 ± 0.08; 1.19 ± 0.46; 1.30 ± 0.5; and 0.24 ± 0.20, for the mesohaline forests, the euhaline forest, and the hyperhaline forest, respectively. The proposed hypotheses were confirmed when considering only the extreme salinity ranges. Upon incorporating all salinity ranges from the four forests into the analysis, it was observed that litter production exhibited a tendency to decrease with increasing salinity, while root production demonstrated a tendency to increase. However, this trend did not attain statistical significance, thereby suggesting that, in addition to salinity, other factors may also regulate production processes. These findings serve to affirm the high productivity of carbonate environments and the contribution of autochthonous production. Full article

Mangrove ecosystems are renowned for their rich fungal diversity, housing a plethora of multicellular fungi and yeasts. In this investigation, we examined the yeast diversity associated with various compartments (rhizospheric soil, stems, roots, leaves, barks, and flowers) of the widely distributed mangrove tree, Avicennia officinalis, from the Kumbalam and Puthuvype mangroves in central Kerala, India. Our study revealed that the yeast strains were not uniformly distributed in various compartments. The highest abundance of yeasts was found in leaves (42%), followed by sediment (21%), and the lowest in flowers (5%). Among the 45 isolates, 27% comprised red yeasts. Dominant genera included Rhodotorula (27.5%), Debaryomyces (17.6%), Kluyveromyces (5.9%), Cryptococcus (9.8%), and Candida (7.8%), while genera such as Geotrichum, Lodderomyces, Ogataea, Galactomyces, and Saitozyma were represented by single isolates. Certain yeast species, such as C. tropicalis and Rhodotorula paludegina, exhibited a cosmopolitan distribution in various plant compartments of A. officinalis. An analysis of the proximate composition of different plant compartments of A. officinalis revealed variations in C, N, S, H, Ca, K, and the C/N ratio. Interestingly, these variations were positively correlated with the yeast community composition, suggesting a potential role of the elemental composition of plants in shaping the yeast biome of A. officinalis. However, our understanding of the inter-relationships among yeast communities in different plant compartments remains limited, highlighting the need for further comprehensive investigations in this field. Full article

In Thailand, mangrove forests form a major component of the Andaman coastal ecosystems in the southern provinces. However, studies on their microbial assemblage largely revolved around groups of bacteria, fungi, and eukaryotic microalgae, while the diversity of cyanobacteria in these regions remains almost unknown. This taxonomic study applied the polyphasic approach to examine seven cyanobacterial strains collected from different mangrove environments (including soil crust, tree bark, wood, and rock surface) across Ranong, Phang-Nga, and Phuket provinces. The comprehensive analysis combining morphology, ecology, 16S rRNA phylogenetic relationships, genetic identity, ITS secondary structure, and ITS dissimilarity resulted in the first records of the genera Picosynechococcus, Allocoleopsis, and Sirenicapillaria in Thailand, and led to the description of a new species, Picosynechococcus mangrovensis sp. nov. This new species was differentiated from the type species P. fontinalis based on the distinct 16S rRNA gene phylogenetic position, low 16S rRNA genetic similarity, its slightly halophilic nature, and ability to form pseudo-filaments with up to 160 cells. Our research significantly expands the documented cyanobacterial diversity of Southeast Asian mangrove ecosystems, establishing a critical foundation for future ecological and biotechnological investigations in these understudied yet vital tropical habitats. Full article

The intensification of economic globalization and the growing scarcity of global land resources have magnified the complexity of future land use and land cover (LULC) changes. In Mainland Southeast Asia (MSEA), these transformations are particularly pronounced, yet comprehensive, targeted, and systematic reviews are scant. This research employs bibliometrics and critical literature review methodologies to scrutinize 1956 relevant publications spanning from 1990–2023, revealing key insights into the contributors to land use studies in MSEA, which include not only local researchers from countries like Thailand and Vietnam but also international scholars from the United States, China, Japan, and France. Despite this, the potential for global collaboration has not been fully tapped. This study also notes a significant evolution in data analysis methods, transitioning from reliance on single data sources to employing sophisticated multi-source data fusion, from manual feature extraction to leveraging automated deep learning processes, and from simple temporal change detection to comprehensive time series analysis using tools like Google Earth Engine (GEE). This shift encompasses the progression from small-scale case studies to extensive multi-scale system analyses employing advanced spatial statistical models and integrated technologies. Moreover, the thematic emphasis of research has evolved markedly, transitioning from traditional practices like slash-and-burn agriculture and deforestation logging to the dynamic monitoring of specialized tree species such as rubber plantations and mangroves. Throughout this period, there has been a growing focus on the broad environmental impacts of land cover change, encompassing soil degradation, carbon storage, climate change responses, ecosystem services, and biodiversity. This research not only offers a comprehensive understanding of the LULC research landscape in MSEA but also provides critical scientific references that can inform future policy-making and land management strategies. Full article

Biscayne Bay in southeastern Florida, USA, has experienced dramatic ecological declines due to pollution. The Biscayne Bay and Southeastern Everglades Ecosystem Restoration will deliver water from a canal adjacent to coastal mangroves, intercepting pollutants before they are deposited into the estuary. Given their demonstrated capacity to filter nutrients and other contaminants from the water column, we hypothesized that mangrove wetlands also filter microplastics (“MPs”). Water and sediment samples were taken from 3 “zones”: the L-31E canal, a potential MP source; interior, dwarf mangroves; and coastal, tidal fringe mangroves. These three environments were replicated in coastal basins with and without canal culverts. MPs were expected to vary seasonally and be more abundant and larger in the dwarf zone and in low-bulk density sediments as particles settled into peat soils. In sediment, MPs were more abundant in the dry season (average 0.073 ± 0.102 (SD) MPs/g dw) before getting flushed by overland runoff resulting in greater concentrations in water during the wet season (average 0.179 ± 0.358 (SD) MPs/L). MPs were most abundant and larger in the low bulk density sediments of the dwarf zone, likely due to sheltering from fragmentation. Culvert presence had no effect, but MPs may increase as waterflows increase to planned volumes. Understanding MP dynamics enables managers to predict water quality impacts and leverage the potential ecosystem service of MP filtration by mangrove wetlands. Full article

Understanding soil microbial community assembly in endangered mangrove ecosystems is crucial for ecological conservation. This study investigated the diversity and drivers of soil microbiomes across Barringtonia racemosa communities (pure: T1; associated: T2, T3) in China’s Leizhou Peninsula, using SMRT sequencing and phospholipid fatty acid analysis. The results reveal that pure B. racemosa communities (T1) harbored the highest microbial diversity (Chao1: 2980 bacteria, 14,378 fungal OTUs), with Pseudomonadota (37.6%) and Ascomycota (52.6%) as dominant phyla. Fungal communities exhibited 3.2-fold higher β-diversity variability than bacteria across communities (Bray–Curtis; p < 0.01). Redundancy analysis identified soil organic carbon (SOC), available nitrogen (SAN), and leaf manganese as primary drivers, collectively explaining 72.4% of microbial variation (p = 0.003). Notably, pure communities showed an elevated SOC (74.3 mg/kg) and fungal: bacterial ratio (0.19 vs. 0.13–0.14 in associated communities), indicating fungal dominance in carbon-rich sediments. Conversely, rice field controls displayed distinct SAP/SAK patterns reflecting agricultural impacts. These findings demonstrate that the B. racemosa community structure differentially regulates fungal assemblages more strongly than bacterial communities, providing critical insights for mangrove restoration through microbial-informed management. Full article

Soil fungi in mangroves are diverse and crucial for organic matter decomposition and element cycling. However, the drivers influencing network complexity and the stability of fungal communities across different mangrove soil habitats remain unclear. This study investigated the main factors driving the composition, diversity, complexity, and stability of fungal communities in clay loam and sandy soils in mangrove ecosystems. Results showed that Dothideomycetes and Sordariomycetes dominated in clay loam and sandy soils, respectively. Sandy soils exhibited higher alpha diversity than clay loam. Beta diversity analysis revealed significant differences in the fungal community structure between the two soil types. Network analysis demonstrated higher complexity and stability of fungal communities in clay loam than in sandy soil. Spearman’s correlation analysis revealed that NH₄⁺-N and total nitrogen were the main factors affecting complexity and stability in clay loam, respectively. Partial least squares path modeling demonstrated that alpha diversity and soil properties were closely linked to the complexity and stability of fungal communities in clay loam, whereas beta diversity was the primary driver in sandy soil. Our study enhances the understanding of the mechanisms that maintain fungal diversity and community stability in mangrove ecosystems, with important implications for restoring vegetation in degraded areas. Full article

Soil chronosequences are crucial for understanding pedogenesis and ecosystem dynamics, yet a systematic bibliometric analysis of this field remains absent. To investigate hotspots and trends, this study used CiteSpace to analyze 4075 publications from the Web of Science Core Collection (1994–2024). The results revealed a steady increase in publications over time, led by the USA (1287 articles) and China (1093 articles). Wardle David A. emerged as the most influential researcher (67,519 citations) for his contributions regarding microbial-driven pedogenic feedbacks. The Chinese Academy of Sciences was the top institution, contributing 13.3% of articles and achieving the highest centrality of 0.21. Geoderma (IF = 5.6) was the most cited journal (2258 citations), with key contributors including Vitousek (530 citations) and Walker (415 citations) from the USA and Wardle (411 citations) from Sweden. Research hotspots in this field were nutrient cycling, vegetation succession/ecological restoration, and soil microbial community dynamics. Three thematic shifts were identified: early focus on conceptual frameworks, expansion to ecological restoration and carbon dynamics, and recent diversification into microbial communities, coastal ecosystems (e.g., mangroves, Spartina alterniflora), and anthropogenic impacts (e.g., heavy metals). The research has evolved significantly from 1994 to 2024, with a growing emphasis on interdisciplinary approaches and practical applications. This analysis provides a comprehensive synthesis of soil chronosequence research, advancing our understanding of pedogenesis and informing sustainable land-management strategies. Full article

Coastal ecosystems, particularly mangroves, are essential for ecological stability and human livelihoods, yet they face significant degradation from natural and anthropogenic pressures. This study focuses on the Chaungkaphee Protected Public Forest (PPF) in the Tanintharyi region of Myanmar, which hosts diverse mangrove species critical for carbon storage. Between 2010 and 2020, mangrove forest cover in Myanmar decreased from 540,000 ha to 431,228 ha, resulting in a loss of 108,772 ha. This decline is primarily attributed to illegal logging and agricultural expansion. Our research aims to assess the structural characteristics, biomass, and carbon storage potential of mangrove ecosystems within the Chaungkaphee PPF. Field data collected in early 2024 applied non-destructive sampling methods to gather information on tree structure, species composition, and soil carbon stocks. We identified six dominant mangrove species, with Rhizophora apiculata Blume showing the highest biomass and carbon storage potential. The total biomass was measured at 493.91 Mg ha⁻¹, yielding a carbon stock of 218.76 Mg C ha⁻¹. Soil carbon assessments revealed an average organic carbon stock of 921.09 Mg C ha⁻¹, underscoring the vital role of soil in carbon sequestration. Our findings highlight the significant contribution of mangrove ecosystems to climate change mitigation, emphasizing the urgent need for effective conservation strategies and community involvement in restoration efforts. This study enhances the understanding of mangrove resilience and sustainability, advocating for the protection of these crucial ecosystems amidst ongoing environmental challenges. By recognizing the ecological functions and services provided by mangroves, we can better address the threats they face and promote their restoration for future generations. Full article

Mangrove forests are vital for flood reduction, yet their failure mechanisms during storms are poorly known, hampering their integration into engineered coastal protection. In this paper, we aimed to unravel the relationship between the resistance of mangrove trees to overturning and root distribution and the properties of the soil, while avoiding damage to natural mangrove forests. We therefore (i) tested the stability of 3D-printed tree mimics that imitate typical shallow mangrove root systems, mimicking both damaged and intact root systems, in sediments representing the soil properties of contrasting mangrove sites, and subsequently (ii) tested if the existing stability models for terrestrial trees are applicable for mangrove tree species, which have unique shallow root systems to survive waterlogged soils. Root systems of different complexities were modeled after Avicennia alba, Avicennia germinans, and Rhizophora stylosa, and printed at a 1:100 scale using material densities matching those of natural tree roots, to ensure the geometric scaling of overturning moments. The mimic stability increased with the soil shear strength and root plate surface area. The optimal root configuration for mimic stability depended on the sediment properties: spreading root systems performed better in softer sediments, while concentrating root biomass near the trunk improved stability in stronger sediments. An adapted terrestrial tree resistance model reproduced our measurements well, suggesting that such models could be adapted to predict the stability of shallow-rooted mangroves living in waterlogged soils. Field tree-pulling experiments are needed to further confirm our conclusions with real-world data, examine complicating factors like root intertwining, and consider mangrove tree properties like aerial roots. Overall, this work establishes a foundation for incorporating mangrove storm damage into hybrid coastal protection systems. Full article

Mangroves grow in high-salinity environments with low soil water potential (Ψ_s), where high light intensity and strong winds increase the vapor pressure deficit (VPD), causing physiological drought and high transpiration demand (Δw), which limits carbon dioxide (carbon gain) for photosynthesis. This study explored how mangroves optimize their carbon-gain-to-water-loss ratio (water-use strategies) to maximize carbon gain during both dry and rainy seasons. We also calculated the relative costs of key leaf traits and compared them with those of terrestrial forests under the carbon gain optimization model. The results revealed that (1) with increasing Δw, terrestrial forests primarily adjusted leaf hydraulic conductance (K_leaf), while mangroves altered the difference in water potential (ΔΨ); (2) as Ψ_s decreased, π_tlp of both terrestrial forests and mangroves increased; (3) terrestrial forests developed a more balanced distribution of leaf trait costs between osmotic pressure (46.7 ± 0.2%) and stomata (43.3 ± 1.2%), whereas mangroves had the highest cost in osmotic pressure (49.04 ± 0.03%) and the lowest cost in stomata (11.08 ± 3.00%) during the rainy season; and (4) although mangroves showed differences in trait values between dry and rainy seasons, their responses to drought stress remained consistent. These findings provided new theoretical insights into how mangroves maintain high carbon gain and water-use efficiency under extreme environmental conditions, which is important to improve mangrove conservation efforts and contribute to climate mitigation policies. Full article