National Soil Organic Carbon Stocks Inventories under Different Mangrove Forest Types in Gabon

Gabonese’s estuary is an important coastal mangrove setting and soil plays a key role in mangrove carbon storage in mangrove forests. However, the spatial variation in soil organic carbon (SOC) storage remain unclear. To address this gap, determining the SOC spatial variation in Gabonese’s estuarine is essential for better understanding the global carbon cycle. The present study compared soil organic carbon between northern and southern sites in different mangrove forest, Rhizophora racemosa and Avicennia germinans. The results showed that the mean SOC stocks at 1 m depth were 256.28 ± 127.29 MgC ha−1. Among the different regions, SOC in northern zone was significantly (p p < 0.001). The deeper layers contained higher SOC stocks (254.62 ± 128.09 MgC ha−1) than upper layers (55.42 ± 25.37 MgC ha−1). The study highlights that low deforestation rate have led to less CO2 (705.3 Mg CO2e ha−1 - 922.62 Mg CO2e ha−1) emissions than most sediment carbon-rich mangroves in the world. These results highlight the influence of soil texture and mangrove forest types on the mangrove SOC stocks. The first national comparison of soil organic carbon stocks between mangroves and upland tropical forests indicated SOC stocks were two times more in mangroves soils (51.21 ± 45.00 MgC ha−1) than primary (20.33 ± 12.7 MgC ha−1), savanna and cropland (21.71 ± 15.10 MgC ha−1). We find that mangroves in this study emit lower dioxide-carbon equivalent emissions. This study highlights the importance of national inventories of soil organic carbon and can be used as a baseline on the role of mangroves in carbon sequestration and climate change mitigation but the variation in SOC stocks indicates the need for further national data.

Potential effects of sea level rise on the soil-atmosphere green-house gas emissions in Kandelia obovata mangrove forests

Mangrove forests are under the stress of sea level rise(SLR)which would affect mangrove soil biogeochemistry.Mangrove soils are important sources of soil-atmosphere greenhouse gas(GHG)emissions,including carbon dioxide(CO_(2)),methane(CH_(4))and nitrous oxide(N_(2)O).Understanding how SLR influences GHG emissions is critical for evaluating mangrove blue carbon capability.In this study,potential effects of SLR on the GHG emissions were quantified through static closed chamber technique among three sites under different intertidal elevations,representing tidal flooding situation of SLR values of 0 cm,40 cm and 80 cm,respectively.Compared with Site SLR 0 cm,annual CO_(2) and N_(2)O fluxes decreased by approximately 75.0%and 27.3%due to higher soil water content,lower salinity and soil nutrient environments at Site SLR 80 cm.However,CH_(4) fluxes increased by approximately 13.7%at Site SLR 40 cm and 8.8%at Site SLR 80 cm because of lower salinity,higher soil water content and soil pH.CO_(2)-equivalent fluxes were 396.61 g/(m^(2)·a),1423.29 g/(m^(2)·a)and 1420.21 g/(m^(2)·a)at Sites SLR 80 cm,SLR 40 cm and SLR 0 cm,respectively.From Site SLR 0 cm to Site SLR 80 cm,contribution rate of N_(2)O and CH_(4) increased by approximately 7.42%and 3.02%,while contribution rate of CO_(2) decreased by approximately 10.44%.The results indicated that warming potential of trace CH_(4) and N_(2)O was non-negligible with SLR.Potential effects of SLR on the mangrove blue carbon capability should warrant attention due to changes of all three greenhouse gas fluxes with SLR.

The Current Status of World Protection for Mangrove Forest

Mangrove forests occur extensively in the tropic areas rich in wildlife and other non forestry resources and provide a wide array of raw materials for livelihood and production processes and have been a major source of income generation and subsistence for the local people. Exploitation of timber, fuel wood, poles, industrial raw material, and many other non wood products from the mangrove forests give rise to large scale economic activity and income generation. At present, mangrove forests are facing great peril. Reckless exploitation and swampland reclamation result in their gradual degradation. This article deals with the worlds mangrove forest resources and their benefit to people; describes the current status, points out the main causes of the destruction of these forests, presents proposals for protecting mangrove forests, and discusses international cooperation in protecting the world’s mangrove forests.

Mangrove forest degradation indicated by mangrove-derived organic matter in the Qinzhou Bay,Guangxi,China,and its response to the Asian monsoon during the Holocene climatic optimum

The response of mangrove ecosystems to the Asian monsoon in the future global warming can be understood by reconstructing the development of mangrove forests during the Holocene climatic optimum（HCO）, using proxies preserved in coastal sediments. The total organic matter in sediments of a segmented core, with calibrated age ranges between 5.6 and 7.7 cal. ka BP and corresponding to the HCO, from the Qinzhou Bay in Guangxi, China, is quantitatively partitioned into three end-members according to their sources： mangrove-derived, terrigenous,and marine phytoplanktonic, using a three-end-member model depicted by organic carbon isotope（δ13Corg） and the molar ratio of total organic carbon to total nitrogen（C/N）. The percentage of mangrove-derived organic matter（MOM） contribution is used as a proxy for mangrove development. Three visible drops in MOM contribution occurred at ca. 7.3, ca. 6.9, and ca. 6.2 cal. ka BP, respectively, are recognized against a relatively stable and higher MOM contribution level, indicating that three distinct mangrove forest degradations occurred in the Qinzhou Bay during the HCO. The three mangrove forest degradations approximately correspond to the time of the strengthened/weakened Asian winter/summer monsoon. This indicates that even during a period favorable for the mangrove development, such as the HCO, climatic extremes, such as cold and dry events driven by the strengthened/weakened Asian winter/summer monsoon, can trigger the degradation of mangrove forests.

Object-Based vs. Pixel-Based Classification of Mangrove Forest Mapping in Vien An Dong Commune, Ngoc Hien District, Ca Mau Province Using VNREDSat-1 Images

Many researches have been performed comparing object-based classification (OBC) and pixel-based classification (PBC), particularly in classifying high-resolution satellite images. VNREDSat-1 is the first optical remote sensing satellite of Vietnam with resolution of 2.5 m (Panchromatic) and 10 m (Multispectral). The objective of this research is to compare two classification approaches using VNREDSat-1 image for mapping mangrove forest in Vien An Dong commune, Ngoc Hien district, Ca Mau province. ISODATA algorithm (in PBC method) and membership function classifier (in OBC method) were chosen to classify the same image. The results show that the overall accuracies of OBC and PBC are 73% and 62.16% respectively, and OBC solved the “salt and pepper” which is the main issue of PBC as well. Therefore, OBC is supposed to be the better approach to classify VNREDSat-1 for mapping mangrove forest in Ngoc Hien commune.

Species Richness and Abundance of Bivalves and Gastropods in Mangrove Forests of Casiguran, Aurora, Philippines

The diversity and abundance of bivalves and gastropods were studied from April to July 2015. Two sampling stations, Tinib and Esteves, in Casiguran, Aurora were selected based on the presence of mangrove forest, bivalves, gastropods, muddy substrate, and gleaners for the establishment of a transect line. Each station was laid with 100 meters transect line overlaid continuously with 2 m × 2 m quadrat along each transect. A total of 50 sampling units covering 0.02 ha area per sampling station were surveyed. The transect line recorded six species of bivalves distributed among five families and 12 species of gastropods belonging to eight families. Three species of bivalves and five species of gastropods were common to both sampling stations. However, Tinib station had most diverse species of bivalves (0.55) while Esteves station had most diverse species of gastropods (0.43). Both stations revealed Dendrostrea folium (43%) (bivalve) and Cerithidea cingulata (93%) (gastropods) as most frequently occurring species. Dendostrea folium also emerged as the densest (10,640 ind∙ha−1 and 6850 ind∙ha−1) and most abundant (58.52% and 77.84%) bivalve species. For gastropods, Terebralia sulcata (249,250 ind∙ha−1) was the densest and most abundant (96.97%) in Tinib while Terebralia palustris was the densest (747,050 ind∙ha−1) and most abundant (70.44%) in Esteves. Pooled results for bivalve species maintained Dendrostrea folium as the densest (8750 ind∙ha−1) and most abundant (64.81%). However, for gastropods, Terebralia palustris emerged as the densest (373,525 ind∙ha−1) and most abundant (56.70%) species. The mangrove forests of Casiguran, Aurora thus contain a variety of bivalves and gastropods with Tinib station dominated by bivalves while Esteves station dominated by gastropods.

Spatial Zonation and Diversity of Bivalves and Gastropods in Mangrove Forests of Casiguran, Aurora, Philippines

This study generally aimed to determine the spatial zonation and diversity of bivalves and gastropods in mangrove forest of Cozo, Esteves and Tinib in Casiguran, Aurora. Specifically, this aimed to determine the species composition and distribution, and determine the relationship between spatial zonation and diversity of bivalves and gastropods as influenced by ecological factors such as vegetation, soil texture, organic matter, soil salinity, and soil pH. A total of 22 taxa comprising eight species of bivalves and 14 species of gastropods were identified. The high tidal zone of Esteves had high diversity (0.66) of bivalve species compared to other tidal zones and areas. On the other hand, the diversity of gastropods was almost equal in the middle tidal zones of Cozo (0.60), Esteves (0.57), and Tinib (0.42). In terms of bivalve species’ density and abundance, Dendostrea folium was the most dense and abundant in the low tidal zone of Cozo (253,333 ind.ha−1 or 25 ind.m2-1, 97.44%) while Gafrarium tumidum in the low tidal zones of Esteves (46,666 ind.ha−1 or 4 ind.m2-1, 73.68%) and Tinib (126,666 ind.ha−1 or 12 ind.m2-1, 50%). In terms of gastropod species’ density and abundance, Cerithidea cingulata was the most dense and abundant in the low tidal zone (666,666 ind.ha−1 or 66 ind.m2-1, 65.79%) of Cozo and the middle tidal zone (5,280,000 ind.ha−1 or 528 ind.m2-1, 61.40%) of Tinib. It was Terebralia palustris in the low tidal zone (1,263,333 ind.ha−1 or 126 ind.m2-1, 63.06%) of Esteves. All tidal zones within each study area had greater dissimilarities in terms of bivalves but had greater similarities in terms of gastropod species’ compositions. On the other hand, all tidal zones between study areas had greater dissimilarities in terms of bivalve and gastropod species present. Most tidal zones had Gafrarium tumidum as common bivalve species while Neritidae sp. and Cerithidea cingulata were common gastropod species. All these species were found thriving in a wide range of vegetation, soil texture, organic matter, soil salinity and pH.

Gender Roles in the Utilization and Challenges in the Management of Mangrove Forests in Casiguran, Aurora, Philippines

Mangrove utilization and management were observed done by men and women depending on their needs and priorities in Casiguran, Aurora. This study, therefore, tried to investigate the gender roles in the utilization and management of mangrove forests, the existing mangrove management practices and their challenges, and the relationship between gender and mangrove resources management. A mixed-method approach was used and data were obtained through triangulation. Respondents were obtained through snowball sampling and interviewed using a structured questionnaire with a few open-ended questions. Results revealed that the majority of the respondents were women (60.7%) and residents of Brgy. Esteves (52.5%) live within or near the mangrove forest. Mostly married (59%) who were providing food and income for the family. They utilized mangrove woods (58.20%) with an average quantity of less than 10 board feet (34.4%) for cooking (40.2%). Roots were utilized in minimal amounts (2.50%) for mythical, medicine, and cork purposes. Mollusks (93.44%), commonly bivalves (93.4%), were primarily gleaned by women for food consumption (93.4%) and as a source of income (93. 61%). On the other hand, catching of crabs (57.4%) for consumption (56.6%) and as a source of income (14.8%) and catching of fish (31.1%) for consumption (27.9%) were done by men. Both genders were involved in mangrove management practices, although only 65% of them had actual involvement in mangrove planting, 19% in mangrove nursery development and maintenance, and 16% in mangrove plantation maintenance. Challenges in management include low survival rate of planted mangroves (33%), lack of maintenance activity (20%), and lack of funds for mobilization (20%). A chi-square test of independence revealed that both men and women have no significant difference in their involvement in nursery establishment and maintenance, mangrove planting, and plantation management.

Mangrove Forest Characterization in Southeast Côte d’Ivoire

Mangrove ecosystems are faced with far more existential threats of erosion than their terrestrial counterparts. Consequences of their degradation vary from decline in edible aquatic stocks, coastal erosion and aquatic weeds invasion. Mangrove forest dynamics was assessed from multi-temporal analyses of remotely sensed satellite images (mosaics of 1989/90 and 2014/15) within 233,900 hectares. Ground-truthing was accompanied by field measurements in selected forest stands to characterize structure, estimate biomass and carbon pools. With conservation as overriding goal, a socio-economic survey was conducted to underpin the factors influencing mangrove forests over-exploitation and qualitatively assess the sensitivity of the locals to resources decline. The region recorded fifty percent loss of mangrove area during the 25-year period. Low leaf area index (1.02 - 2.52 m2·m-2) confirms canopy openness. Above-ground root biomass (kg per root) ranged between 110.67 and 382.64. The roots demonstrate capacity to fix up to 176 Mg C ha-1 with average carbon content of 46 percent. Highest carbon pools were in the Eloka-To forest stands, in near natural conditions. Despite harsh environmental conditions, potential for natural regeneration was evidenced by seedlings density (individuals per m2) up to 76. Pilot survey revealed high dependence on mangrove resources for direct income (70 percent) and daily energy needs (60 percent). Despite the heightened awareness of the impending dangers posed by mangrove deforestation and willingness to conserve, riverine communities are incapacitated by lack of viable economic alternatives. External interventions are therefore imperative to achieve conservation goals with long-term implications for climate change adaptation and mitigation.

Comparison of Water Quality Status of Disturbed and Undisturbed Mangrove Forest at Awat-Awat Lawas Sarawak

Water quality testing was compulsory for management of safe and reliable water sources. Various sources of pollution and destruction of mangrove forest decrease the quality of river water. Thus a study was conducted to determine the water quality status of mangrove forest river water of Awat-Awat Lawas Sarawak and compare the water quality status of disturbed and undisturbed mangrove forest river in that area. Samples from twelve sampling stations were collected from both mangrove forest river from October 2013 to March 2014. In-situ data collected (pH, temperature, dissolved oxygen (DO), salinity, turbidity, total dissolved solid (TDS), conductivity) and laboratory analysis (biochemical oxygen demand (BOD), chemical oxygen demand (COD), ammoniacal nitrogen (AN), total suspended solid (TSS)) were conducted according to the Standard method of Examination of Water and Wastewater AHPA 2005. Six water parameters: pH, DO, BOD, COD, AN and TSS value were used in calculating the Water Quality Index (WQI). Mean values for disturbed area were follows, pH (7.07), temperature (29.93°C), salinity (15.64 PSU), turbidity (55.13 NTU), DO (4.59 mg/L), BOD (0.73 mg/L), COD (10.16 mg/L), AN (0.14 mg/L), TSS (53.92 mg/L), TDS (23.14 mg/L) and conductivity (2.61 ms/m). Undisturbed area results were, pH (6.84), temperature (28.32°C), salinity (14.65 PSU), turbidity (35.41 NTU), DO (2.39 mg/L), BOD (0.55 mg/L), COD (15.82 mg/L), AN (0.13 mg/L), TSS (53.23 mg/L), TDS (22.82 mg/L) and conductivity (2.34 ms/m). There were no significant differences between two locations except for DO. Both water qualities of disturbed and undisturbed mangrove forest river were found under Class III, which describe that the water bodies are in moderate quality status.

Review on Possible Factors for Outbreak of Wood Boring Isopod, Sphaeroma spp. Which Causes Destructive Impact on Mangrove Forest in China

The tropical and subtropical mangrove biomes form the foundation of a highly productive and biologically rich ecosystem providing essential goods and services to human beings. Despite its values, the stability and survival of mangroves are consistently threatened by anthropogenic activities and their associated degradation, resulting in their disappearance. After realizing their ecological importance, in recent years, rehabilitation and restoration programs for mangrove forests have been launched globally. Unfortunately, most mangrove restoration efforts yielded negative results and failed to re-establish mangrove forests because of technical and social failures. Besides, the continued outbreak of wood borer, Sphaeroma spp., in mangrove forests has become one of the destructive causes of natural and restored mangrove forests in some nations including China. However, few studies on the biology of Sphaeroma spp. found in Chinese mangrove ecosystem have been done, and little is known concerning the factors affecting their outbreak in China. In this review, we discussed the possible factors that affect the rapid growth and recruitment of Sphaeroma spp. in the mangrove ecosystem by examining the information of the wood borer Sphaeroma spp. from the scattered pieces of literature with great regard. We discussed the relationship between the recruitment of Sphaeroma spp. and the tide and flow of water, food availability from the surrounding water and water quality including salinity, temperature, and the pollution of water. In addition to these factors, the reduced biodiversity of restored mangrove forest could be one of the main reasons for the outbreak of isopod. We also discussed the destructive impact of the isopod’s outbreak and the possible ways to control their outbreak in mangrove forest.

Study on the Establishment of Demonstration Site for Peatland Conservation through Integrated Management and Sustainable Utilization of Non-timber Forest Products(NTFPs)

A participatory action research was conducted in 2022,with the“Establishment of Demonstration Site for Peatland Conservation through Integrated Management and Sustainable Utilization of Non-Timber Forest Products(NTFPs)”to give recommendation on the development of guidelines on Sustainable Utilization of Non-Timber Forest Products(NTFPs)and peatland conservation.According to the peat soil assessment,it was found that peat soil content was very low and top soil was thin under the mangrove forest,and Payena paralleloneura-Kan Zaw bearing forest in March 2022.Organic material might be pressed by trespasser to collect Kan Zaw seed,to conduct horticulture and mining near the Kan Zaw bearing forest,or organic material might be damaged by burning with controlled fire in the previous years,under Kan Zaw trees to collect seeds.Organic material might have been carried to the downwards with running water due to the heavy rainfall,with 4,700 mm/year.Mangrove forest and Kan Zaw bearing evergreen forest can be assumed as“the major source of coastal peatland formation,with peat deposits eroded seawards”.It is assumed that the organic material will accumulate on top of the sands and it will lead to the formation of the peatland at coastal zone.It can be assumed that the accumulation of organic material found in mangrove forest and evergreen forests will promote the soil carbon storage,if we can adopt the ASEAN Policy on Zero Burning,which reflect ASEAN's commitment to controlling fires and haze,offering techniques,benefits,requirements,and challenges for implementing zero burning practices[1].Sustainable utilization of NTFP including peat and Kan Zaw-Payena paralleloneura Kurz seed was studied at demonstration sites,and it is recommended to make a trial on silvicultural system at mangrove forest and apply suitable silvicultural system such as Clear-Felling(in blocks or in alternate strips)system,Selection System,and Shelter Wood System to ensure the sustainable utilization of NTFP from mangrove forest[2].Gap planting and assisted natural regeneration are also recommended for mangrove forest and Kan Zaw-bearing forest.

Comparative and Prospective Evaluation of the Carbon Potential of the Mangrove of the Sine-Saloum Delta (Senegal) from 2016 to 2021

With the rupture of the Sangomar spit and climate change, ecosystem functions such as carbon absorption and storage by the Saloum Delta Biosphere Reserve are threatened. Initiatives are carried out as a response to the degradation of the mangrove ecosystem, such as the PRECEMA project. To measure its impact, an assessment of the carbon potential of the mangrove was conducted in 2016 on permanent plots. The present study is part of the monitoring of carbon potential. It aims to contribute to the updating of information on the evaluation of carbon storage potential. The method “afforestation and reforestation of degraded mangrove habitats on a large scale CDM or AR-AM0014 version 04.0” was applied. The mangrove vegetation assessed is dominated by Rhizophora racemosa with 69.9% of the total. With a relatively bushy habit (height = 1.91 m), the height distribution shows a right skewness (Skewness = 2.17;Kurtosis = 4.07) with a tail containing more observations than a normal distribution. The distribution is observed for diameters is skewed with Skewness = 1.5 but Kurtosis = 2.3. Thus the stand is young with an average diameter of 3.90 cm and 79.6% of the trees have a diameter 5 cm. The annual increase in carbon potential of the mangrove has decreased by 80% in 5 years (2016 assessment - 2021 assessment). For a 15-year period, the total carbon stock projected by the model increases globally from 201.396 TeqCO2 in 2011 to 277,318 TeqCO2 in 2026. The projections showed an overall annual stock decrease of 14,164 TeqCO2 (94%). For 2021, the total projected stock (270.289 TeqCO2) is slightly higher than the assessed stock (251.059 TeqCO2), a difference of 7%. Also, the projected annual carbon stock for 2021 (2844 TeqCO2) is higher than the assessed stock (1353 TeqCO2), a gap of 52%.

Vertical Distribution and Pollution Assessment of Heavy Metals in Mangrove Sediments of Dongzhai Harbor, Hainan

This study was conducted to reveal the vertical distribution and concentration variation of heavy metals（Cr, Co, Ni, Cu, Zn, As, Cd and Pb） in the mangrove sediments of Dongzhai Harbor, Hainan by using inductively-coupled plasma mass spectrometry（ICP-MS）. The surface sediment samples were collected from 15 sites, and a geoaccumulation index（Igeo） was estimated to quantify the pollution status of the mangrove sediments. The results showed that the concentrations of heavy metals in sediments followed the order of Cr〉 Zn〉 Ni〉 Cu 〉Pb 〉Co〉 Cd. A common pattern was found in some heavy metals（Cu, Zn, As and Pb） as their concentrations were significantly and negatively correlated with depth. Cr concentration in upper layer was slightly lower than that in middle and lower layers,while the concentrations of Ni and Cd in middle layer were slightly higher than in upper and lower layers. The geoaccumulation index indicated that the surface sediments at sites QT-1-01, QT-1-02, QT-2, GN-1, GN-2 and GN-3 were strongly polluted by Cd, and unpolluted to moderately polluted or moderately polluted by As.

Biomass accumulation and organic carbon stocks of Kandelia obovata mangrove vegetation under different simulated sea levels

Mangrove forests are vulnerably threatened by sea level rise(SLR).Vegetation organic carbon(OC)stocks are important for mangrove ecosystem carbon cycle.It is critical to understand how SLR affects vegetation OC stocks for evaluating mangrove blue carbon budget and global climate change.In this study,biomass accumulation and OC stocks of mangrove vegetation were compared among three 10 year-old Kandelia obovata(a common species in China)mangrove forests under three intertidal elevations through species-specific allometric equations.This study simulated mangrove forests with SLR values of 0 cm,40 cm and 80 cm,respectively,representing for the current,future~100 a and future~200 a SLR of mangrove forests along the Jiulong River Estuary,China.SLR directly decreased mangrove individual density and inhibited the growth of mangrove vegetation.The total vegetation biomasses were(12.86±0.95)kg/m^2,(7.97±0.90)kg/m^2 and(3.89±0.63)kg/m^2 at Sites SLR 0 cm,SLR40 cm and SLR 80 cm,respectively.The total vegetation OC stock decreased by approximately 3.85 kg/m^2(in terms of C)from Site SLR 0 cm to Site SLR 80 cm.Significantly lower vegetation biomass and OC stock of various components(stem,branch,leaf and root)were found at Site SLR 80 cm.Annual increments of vegetation biomass and OC stock also decreased with SLR increase.Moreover,significant lower sedimentation rate was found at Site SLR 80 cm.These indicated that SLR will decrease mangrove vegetation biomass and OC stock,which may reduce global blue carbon sink by mangroves,exacerbate global warming and give positive feedback to SLR.

Fractionation of Organic Carbon and Stock Measurement in the Sundarbans Mangrove Soils of Bangladesh

Mangrove soils are well known for their high capacity of storing organic carbon (SOC) in various pools;however, a relatively small change in SOC pools could cause significant impacts on greenhouse gas concentrations. Thus, for an in-depth understanding of SOC distribution and stock to predict the role of Sundarbans mangrove in mitigating global warming and greenhouse effects, different extraction methods were employed to fractionate the SOC of Sundarbans soils into cold-water (CWSC) and hot-water (HWSC) soluble, moderately labile (MLF), microbial biomass carbon (MBC), and resistant fractions (RF) using a newly developed modified-method. A significant variation in total SOC (p < 0.001), SOC stock (p < 0.001) and soil bulk density (p < 0.05) at the Sundarbans mangrove forest were observed. In most soils, bulk density increased from the surface to 100 cm depth. The total SOC concentrations were higher in most surface soils and ranged from 1.21% ± 0.02% to 8.19% ± 0.09%. However, C in lower layers may be more resistant than that of upper soils because of differences in compositions, sources and environmental conditions. SOC was predominately associated with the resistant fraction (81% - 97%), followed by MLF (2% - 10%), HWSC (1% - 4%), MBC (~0% - 4%), and CWSC (~0% - 3%). The significant positive correlations between different C fractions suggested that C pools are interdependent and need proper management plans to increase these pools in Sundarbans soils. The SOC stock of the studied areas ranged between 16.75 ± 3.83 to 135.12 ± 28.61 kg·C·m−2 in 1 m soil profile and has an average of 31.80 kg·C·m−2. The substratum soils had more carbon than the upper layers in the Sundarbans wetland due to burial and preservation of carbon by frequent tidal inundation. A higher SOC stock in the soil profile and its primary association in resistant fractions suggested that Sundarbans mangrove soil is sequestering carbon and thereby serving as a significant carbon sink in Bangladesh.

Antibacterial activities of mangrove leaf endophytic fungi from Luzon Island,Philippines

Fungi associated with mangroves are untapped sources of bioactive secondary metabolites.In this study,628 mangrove leaf endophytic fungi(MLEF)were recorded from 19 mangrove hosts collected from the provinces of Zambales,Batangas,Cavite,and Quezon in Luzon Island,Philippines.The MLEF morphospecies were identified as belonging to the genera Aspergillus,Cladosporium,Colletotrichum,Fusarium,Nigrospora,Penicillium,Pestalotiopsis,Phialophora,and Trichoderma.Screening revealed that the MLEF crude culture extracts were promisingly potent against the gram-positive bacteria Staphylococcus aureus and Micrococcus luteus(ZOI>19 mm)with no or partial activity against the gram-negative bacteria Klebsiella oxytoca and Pseudomonas aeruginosa.Our findings showed that mangrove leaf endophytic fungi are potential sources of bioactive compounds.

Impact and prediction of pollutant on mangrove and carbon stocks:A machine learning study based on urban remote sensing data

Mangrove ecosystems have important ecological and economic values,especially their ability to store carbon.However,in recent years,human disturbance has accelerated mangrove degradation.Among them,the emission of pollutants cannot be ignored.It is of great significance for carbon emission reduction and ecological protection to study the impacts of different pollutants on mangroves and their carbon stocks.Based on the remote sensing data of coastal areas south of the Yangtze River in China's Mainland,this paper builds the ensemble learning model Random Forest(RF)and Gradient Boosting Regression(GBR)to empirically analyse the relationship between industrial wastewater,industrial sulfur dioxide(SO2),PM2.5 and mangrove forests.The results show that the pollutant concentration of meteorological normalisation is more stable.The importance of pollutants presents regional heterogeneity.The area of mangroves in different cities and the corresponding total carbon stocks show different trends with the increase or decrease of pollutants,and there is a dynamic balance between urban pollutant discharge and mangrove growth in some cities.The research in this paper provides an analysis and explanation from the perspective of machine learning to explore the relationship between mangroves and pollutants and at the same time,provides scientific suggestions for the formulation of future pollutant emission policies in different cities.

Modeling projected changes of mangrove biomass in different climatic scenarios in the Sunda Banda Seascapes

Mangroves are critical in the ecological,economic and social development of coastal rural and urban communities.However,they are under threat by climate change and anthropogenic activities.The Sunda Banda Seascape(SBS),Indonesia,is among the world’s richest regions of mangrove biomass and biodiversity.To inform current and future management strategies,it is critical to provide estimates of how mangroves will respond to climate change in this region.Therefore,this paper utilized spatial analysis with model-based climatic indicators(temperature and precipitation)and mangrove distribution maps to estimate a benchmark for the mangrove biomass of the SBS in six scenarios,namely the Last Inter-glacial Period,the current scenario(1950-2000)and all four projected Representative Concentration Pathways in 2070 due to climate change.Despite mangroves gaining more biomass with climate change(the increase in CO_(2)concentration),this paper highlighted the great proportion of below-ground biomass in mangrove forests.It also showed that the changes in spatial distribution of mangrove biomass became more variable in the context of climate change.As mangroves have been proposed as an essential component of climate change strategies,this study can serve as a baseline for future studies and resource management strategies.