Natural Mangrove Research Articles

How exotic Sonneratia species affect the spatiotemporal dynamics of mangroves in Shenzhen Bay, China: A remote sensing perspective

Mangroves are essential forest communities in tropical and subtropical coastal zones, providing unique ecological functions and significant social and economic value. Accurate and efficient monitoring of mangroves is crucial for their protection and management. The impact of exotic species on native species is still debated, especially for mangroves, the spatiotemporal dynamics of introduced species and native mangrove species need to be closely monitored. This study aimed to investigate how exotic mangrove species affects the spatial dynamics of mangroves in Shenzhen Bay, China. Yearly Landsat images from 2000 to 2011 and Chinese high spatial resolution images during 2012–2022 were obtained and the pixel-based and multiscale object-based methods were used to obtain mangrove distribution. The results showed that: (1) Overall, mangroves in the study area increased from 281.51 ha to 526.43 ha from 2000 to 2022, with different spatiotemporal patterns in Shenzhen (+5.14%) and Hong Kong (+2.38%); (2) rapid spread of Sonneratia species was one of the main contributions to the growth of mangrove hotspots, and growth hotspots were mainly concentrated in the estuary delta; and (3) Sonneratia mangrove species was dominant in interspecific competition, not only invading the habitat of local mangroves, but also preventing the expansion of native mangrove growth. The results provide a reference for fine-scale and accurate mangrove mapping with high spatial and temporal resolutions, and highlight the need to pay more attentions to the spread and invasive potential of exotic mangrove species in the study area, as well as cooperation in adjacent reserves.

Thermomonas mangrovi sp. nov., isolated from soil of a mangrove nature reserve.

A Gram-stain-negative, non-motile, aerobic and ovoid-rod-shaped bacterial strain, designated as 2C3345T, was isolated from soil of a mangrove nature reserve in Shenzhen, PR China and its taxonomic position was investigated. The 16S rRNA gene sequence of strain 2C3345T exhibited the highest similarity value to that of the type strains Thermomonas aquatica NBRC 113114T (98.4 %), Thermomonas carbonis KCTC 42013T (98.1 %), Thermomonas brevis DSM 15422T (98.0 %) and Thermomonas haemolytica DSM 13605T (97.9 %). Strain 2C3345T grew optimally at 28-30 °C, pH 7.0 and without NaCl. The predominant ubiquinone in 2C3345T was identified as Q-8. The major fatty acids of 2C3345T were iso-C15 : 0, iso-C16 : 0 and summed feature 9 (is0-C17:1ω9c and/or 10-methyl C16:0). The major polar lipids of 2C3345T were phosphatidylcholine (PC), phosphatidylglycerol (PG), diphosphatidglycerol (DPG), phosphatidylethanolamine (PE), an unidentified phospholipid, an unidentified aminolipid and two unidentified lipids. The DNA G+C content of strain 2C3345T was 69.9 %. The draft genome sequence of 2C3345T included 2 888 645 bp in total (N50=310 730 bp) with a medium read coverage of 388.6×and 21 scaffolds. In silico DNA-DNA hybridisation with type strains of species of the genus Thermomonas showed 24.4, 22.4, 24.1 and 23.2% relatedness to T. aquatica NBRC 113114T, T. carbonis KCTC 42013T, T. brevis DSM 15422T and T. haemolytica DSM 13605T, respectively. And the average nucleotide identity by blast (ANIb) values between 2C3345T and these four reference strains were 81.9, 80.0, 81.2 and 80.6 %, respectively, lower than the 95-96% threshold value for dividing prokaryotic species. On the basis of its phenotypic, chemotaxonomic, phylogenetic and phylogenomic properties, strain 2C3345T is considered to represent a novel species within the genus Thermomonas, for which the name Thermomonas mangrovi sp. nov. is proposed. The type strain is 2C3345T (=KCTC 92730T =MCCC 1K08335T).

KARAKTER VEGETASI, KEANEKARAGAMAN MAKROZOOBENTOS DAN KARBON PADA SEDIMEN DI KAWASAN MANGROVE NUSA LEMBONGAN DAN ESTUARI PERANCAK

Natural mangroves can be found in Nusa Lembongan, which is bordered by coral reefs, while in the Perancak Estuary, some of the lands are former ponds. The aim of the study was to determine the density, canopy cover, and organic carbon content in mangrove sediments. Data were collected from 3 stations, using transects measuring 10 x 10 m to determine density, height, trunk circumference, and canopy cover, as well as macrozoobenthos sampling. The mangrove density in Lembongan is very high, the tree height reaches 8 – 10 meters, and the mangrove canopy cover is in a good category. The macrozoobenthos diversity index is in the medium category and the carbon content in the sediments is high. Mangroves in Perancak Estuary are densely dense, with an average tree height of 8 meters, and canopy cover in the good category. The index of macrozoobenthos diversity was moderate and the organic carbon in the sediments was lower than in the mangroves at Nusa Lembongan. The character of the mangrove vegetation is different in the two areas. The Nusa Lembongan mangrove growing area is directly opposite the sea, but in the Perancak Estuary, it tends to be closed and flows by a large river around it. The mangrove growth zone is still natural in the Nusa Lembongan area, in contrast to the Perancak Estuary mangrove area which has been rehabilitated at several points.
 Keywords: Mangrove vegetation; macrozoobenthos; carbon on sediment

Protaetiibacter mangrovi sp. nov., isolated from mangrove soil.

A novel Gram-stain-positive, aerobic, non-flagellated and rod-shaped actinobacterium, designated 10F1B-8-1T, was isolated from mangrove soil sampled at Futian Mangrove Nature Reserve, China. The isolate was able to grow at 10-40 °C (optimum 30-32 °C), at pH 6-8 (optimum 7) and in the presence of 0-6% (w/v) NaCl (optimum 0%). Strain 10F1B-8-1T shared the highest 16S rRNA gene sequence similarity to Protaetiibacter larvae NBRC 113051T (98.3%), followed by Protaetiibacter intestinalis NBRC 113050T (98.2%). Phylogenetic trees based on 16S rRNA gene sequences and the core proteomes exhibited that strain 10F1B-8-1T formed a new phyletic line in the clade of genus Protaetiibacter, indicating that this strain belonged to the genus Protaetiibacter. Strain 10F1B-8-1T showed low average nucleotide identity (<84%) and digital DNA-DNA hybridization values (<27%) with closely related taxa, suggesting that strain 10F1B-8-1T was a hitherto undescribed species of the genus Protaetiibacter. Strain 10F1B-8-1T contained D-2,4-diaminobutyric acid as the diagnostic diamino acid, and the peptidoglycan type was characterized as type B2β. The major fatty acids were iso-C16:0, anteiso-C15:0 and anteiso-C17:0. The major menaquinones were MK-13 and MK-14. The polar lipid profile included diphosphatidylglycerol, phosphatidylglycerol, an unidentified glycolipid and five unidentified lipids. Notably, the ethyl acetate extracts of strain 10F1B-8-1T showed effective antibacterial activity against Bacillus subtilis CPCC 100029 and Escherichia coli △tolC. According to the polyphasic data, strain 10F1B-8-1T should be classified as a novel species of the genus Protaetiibacter, for which the name Protaetiibacter mangrovi sp. nov. is proposed, with the type strain 10F1B-8-1T (=JCM 33142T = CPCC 205428T).

Valuasi Ekonomi Dan Potensi Pengembangan Objek Wisata Hutan Mangrove Kampung Nelayan Sejahtera Kelurahan Sumber Jaya Kota Bengkulu

This study aims to determine the economic value of mangrove forest tourism objects in the Prosperous Nelayan Village, Sumber Jaya Village, Kampung Melayu Subdistrict Baai Island, Bengkulu City through economic instruments, namely the Travel Cost Method (TCM) and Willingness to Pay (WTP) along with the variables that influence it and to determine the potential for development based on visitor perceptions. The number of respondents in this study were 50 people. Estimation of economic value is based on the Travel Cost Method, while the factors that influence Willingness to Pay are analyzed using multiple linear regression. Furthermore, the potential for tourism object development is studied descriptively based on the respondents' perceptions. The results showed that the economic value of the mangrove forest tourist attraction Kampung Nelayan Sejahtera based on the total travel costs of 50 respondents during 2 weeks of observation was Rp.5,088,000. The factors that influence the Willingness to Pay for the Mangrove Forest tour of Kampung Nelayan Sejahtera are the total cost of the trip, the age of the respondent, and income. Total travel costs and age have a negative effect on Willingness to Pay, while income has a positive effect on Willingness to Pay. Potential developments that can be carried out are (1) development of all potential natural resources in the Kampung Sejahtera Mangrove Forest such as natural mangrove forest views, biodiversity and community friendliness and culture by building cooperation between the community and all competent parties, (2 ) Packaging the offered tourist objects with a tourism promotion package to attract visitors from outside the City of Bengkulu, and (3) increasing the construction of tourist facilities, facilities and infrastructure that are urgently needed by tourists/visitors and making improvements to existing infrastructure facilities. having damaged.

The linkages between stomatal physiological traits and rapid expansion of exotic mangrove species (Laguncularia racemosa) in new territories

The fast-growing exotic mangrove species (Laguncularia racemosa) has been widely introduced in new territories such as China to restore mangrove ecosystems. However, the invasiveness, as well as the mechanisms for the rapid expansion after the introduction are still not well studied. Here, we try to reveal possible micro-mechanisms for the fast expansion of L. racemosa, using the data on leaf stomata straits, gas-exchange parameters, stable isotope ratios, carbon-nitrogen allocation from L. racemosa and the adjacent native mangroves (Avicennia marina, Aegiceras corniculatum, Bruguiera gymnorhiza, Kandelia obovata) in Hainan Island, China. We found that the higher density but smaller size stoma of L. racemosa enhanced stomatal conductance and shorten the diffusion path of carbon dioxide, thereby increasing the photosynthetic rate. Moreover, the higher stomatal density of L. racemosa exerts a significant positive effect on transpiration, which thus accelerated the water transport and nutrient uptake to meet the advanced need for nutrients and water for fast-growing. The evidence from leaf δ13C and carbon-nitrogen allocation further proved that L. racemosa has a lower intrinsic water use efficiency but a higher rate of photosynthesis than native mangrove species. Our results suggest that stomatal morphological and physiological traits could strongly influence the growth of L. racemosa compared to the adjacent native mangroves, which provides a new perspective for the fast expansion of exotic mangrove species in China. These findings also suggest that L. racemosa has an invasive potential in native mangrove habitats, thereby the mangrove reforestation projects by introducing L. racemosa should be treated with caution.

Will short-term constraints affect long-term growth? Empirical analysis from the Beibu Gulf Mangrove National Natural Reserve of China

The capability approach has long been confined to a static, short-term framework, preventing it from truly providing normative guidance for enhancing multidimensional well-being and sustainable development. Human well-being cannot be seen as fixed, so there is an urgent need to assess the capability approach from a dynamic and long-term perspective. In this paper, the Beibu Gulf Mangrove National Natural Reserve of China was selected as a study area. A sustainable development perspective was integrated into a static capability approach theory framework, focusing on changes in capability approach with a dynamic, long-term gaze, and the impact of coastal zone ecological protection policies on farmers' multidimensional well-being was measured at spatial and temporal scales. The results indicate that ecological conservation policies reduce the level of capability approach of farm households in the short term. However, from a dynamic and long-term perspective, once the “pain period” is over, the capability approach can be continuously improved, achieving a win-win situation for both farmer well-being and ecological sustainability. This result also innovatively verified the core of the capability approach, which states that “freedom” under the capability approach framework is not unrestricted freedom, but restricted freedom. This will further expand and improve the relevant research of Sen's capability approach theory, and is also a beneficial exploration of combining Sen's capability approach theory with the Sustainable Development Goals. In order to solve the contradiction between peasant household welfare development and environmental protection, we need to explore a new scheme. The results of the study provide the government and policy makers with ideas for improving ecological protection policies, along with a more accurate and scientific basis for optimizing the multidimensional welfare compensation system to improve the feasibility and effectiveness of policy implementation.

Sediment CO2 Flux from a Mangrove in Southern China: Is It Controlled by Spatiotemporal, Biotic or Physical Factors?

Carbon gas flux is important for studies on carbon dynamics in mangroves, but the controlling factors have not always been sufficiently understood. In this study, it is suggested that sediment carbon dioxide (CO2) fluxes in a natural mangrove in Southern China are controlled by tidal positions, seasons, species, the densities of crab burrows and pneumatophores, light conditions and sediment temperature. All these factors account for 51.47% variation in CO2 flux from the sediment–air interface. CO2 flux generally decreased along the tidal position from landward to seaward, and was higher in the dry season than in the wet season. CO2 flux was highest in Avicennia marina (grey mangrove) in comparison with Aegiceras corniculatum (river mangrove) and Kandelia obovata. Pneumatophores and crab burrows promoted sediment CO2 flux in the mangrove at a rate of 18.29 and 15.52 mmol m−2 d−1. Dark flux was higher than light flux. Sediment temperature has a negative influence on CO2 flux. Pneumatophores explain the most variation (13.9%) in CO2 flux among the above factors. Our study suggests that the photosynthesis activity of microphytobenthos is an important factor driving the change of CO2 emissions in this natural mangrove. This is of great significance for the study and for the full exploitation of the carbon sink potential of mangroves.

Assessment of urban green areas towards changing surface energy balance fluxes in tropical study sites, Central Thailand

The surface energy balance is broadly accepted as the interaction of the available energy fluxes that leads to the evaporation of surface water and an increase or decrease in the temperature of the surface and pertinent environment. This concept is widely utilized, shifting the increasing urbanization towards sustainable cities on a scientific basis for the planning and management of urban areas. Understanding the ambient factors governing energy fluxes will help mitigate the environmental burden linked to climate change by optimizing the layout of sustainable townships. For a quantitative description, we applied the eddy covariance method, which is one of the most widely accepted methods of monitoring flux changes, at different land-usage and surface-cover locations in an urban area (Kasetsart University (KU) tower), a rural natural mangrove forest environmental system (LERD project), and a spacious urban park estate (Bangkok, Bangkajao District). The results suggested that urban land usage has led to a shift in the ratios of energy fluxes, in which the proportion of latent heat in the mangrove forest area, Bangkajao Green Urban Park, and KU tower were 41%, 29%, and 22%, respectively. However, sensible heat at the KU tower, which is located in the denser urban areas of Bangkok, was predominant at 39% of the heat flux, whereas the transfer of energy into sensible heat in the LERD project and Bangkajao was 17% and 26%, respectively. This study reveals an increase in sensible heat in urban areas and a decrease in latent heat fluxes. Measurements linked to land-use classification showed that changes in the urban structure significantly contributed to heat in the spatial and temporal scales and indicated necessary avenues for the management of urban heat islands and mitigation of related adverse effects.

Assessment of coastal change detection on an urban coastline: A case study in metropolitan Manila, Philippines

The coastal zone around the urban coastline of Metro Manila is said to be suffering major environmental difficulties due to fast population growth and urbanization. This study uses remote sensing and GIS techniques to (i) examine changes in land use/land cover and (ii) detect coastal changes. Between 1992 and 2020, four Landsat map images were obtained to create land-use/land-cover (LULC) maps to detect shoreline changes. Each dataset is subjected to an accuracy assessment, with an average LULC mapping accuracy of roughly 90%. The northern part of the study area, which is in Navotas City was composed of trees and grasslands but as the years went by it was converted into fishponds while the critically important Ramsar site, LPPCHEA, have maintained the preservation of its natural mangrove forest. In a 30-year period, the urban coastline of Metro Manila decreased by around 1.5 kilometers. This study can be used to design a long-term plan and environmental management strategy of Metro Manila.

Community Empowerment through Sustainable Utilisation of Mangrove Forests for the Production of Natural Dyes with An Environmentally Friendly System (Phase I: Increasing Awareness and Knowledge Enhancement)

Community participation in mangrove forest ecosystem conservation is an effort to overcome and avoid mangrove ecosystem deterioration. The findings show that mangrove forests in Kampung Laut’s coastal region, particularly in the village of Ujung Alang, are still well preserveddue to diverse mangrove planting efforts. Currently, the community uses mangrove plants by converting some plant sections into food and using the plant’s stems as building materials. Efforts have been made to preserve mangrove forest ecosystems through the Sustainable Utilization of Mangrove Forests for the Production of Natural Dyes with a Zero Waste System. The following are the activities: 1) Dissemination of the concept to raise public awareness of the potential of mangrove plants as a source of raw materials for natural dyes to increase community income and sustainably manage mangrove forests; 2) Raising the awareness of the younger generation to improve the local economy through the development of micro-scale SMEs in the field of mangrove-based natural dyes; and 3) Technical training on thinning/logging and sustainable mangrove planting to acquaint participants with the concepts of thinning/logging and sustainable man Establish the program’s purpose, which should be divided into six activities. Many farmer groups anticipate that this community service under the auspices of Krida Wana Lestari will assist them in improving their existing products and estimating the potential process of their natural mangroves. This program raises public awareness of the mangrove plant’s potential as a source of raw materials for natural colours. In addition, this activity enables the community to do technical logging and sustainable mangrove planting to support the availability of raw materials for natural dyes. Consequently, the creation and development of a local economic business unit with a green entrepreneurship incubator model based on mangrove conservation and zero waste from natural dye SMEs have begun.

Importance of mangrove plantations for climate change mitigation in Bangladesh.

Mangroves have been identified as blue carbon ecosystems that are natural carbon sinks. In Bangladesh, the establishment of mangrove plantations for coastal protection has occurred since the 1960s, but the plantations may also be a sustainable pathway to enhance carbon sequestration, which can help Bangladesh meet its greenhouse gas (GHG) emission reduction targets, contributing to climate change mitigation. As a part of its Nationally Determined Contribution (NDC) under the Paris Agreement 2016, Bangladesh is committed to limiting the GHG emissions through the expansion of mangrove plantations, but the level of carbon removal that could be achieved through the establishment of plantations has not yet been estimated. The mean ecosystem carbon stock of 5-42 years aged (average age: 25.5 years) mangrove plantations was 190.1 (±30.3)Mg C ha-1 , with ecosystem carbon stocks varying regionally. The biomass carbon stock was 60.3 (±5.6)Mg C ha-1 and the soil carbon stock was 129.8 (±24.8)Mg C ha-1 in the top 1 m of which 43.9 Mg C ha-1 was added to the soil after plantation establishment. Plantations at age 5 to 42 years achieved 52% of the mean ecosystem carbon stock calculated for the reference site (Sundarbans natural mangroves). Since 1966, the 28,000 ha of established plantations to the east of the Sundarbans have accumulated approximately 76,607 Mg C year-1 sequestration in biomass and 37,542 Mg C year-1 sequestration in soils, totaling 114,149 Mg C year-1 . Continuation of the current plantation success rate would sequester an additional 664,850 Mg C by 2030, which is 4.4% of Bangladesh's 2030 GHG reduction target from all sectors described in its NDC, however, plantations for climate change mitigation would be most effective 20 years after establishment. Higher levels of investment in mangrove plantations and higher plantation establishment success could contribute up to 2,098,093 Mg C to blue carbon sequestration and climate change mitigation in Bangladesh by 2030.

Paenibacillus mangrovi sp. nov., a novel endophytic bacterium isolated from bark of Kandelia candel.

A endospore-forming bacterium, designated strain KQZ6P-2T, was isolated from surface-sterilized bark of the mangrove plant Kandelia candel, collected from Maowei Sea Mangrove Nature Reserve in Guangxi Zhuang Autonomous Region, China. Strain KQZ6P-2T was able to grow at NaCl concentrations in the range of 0-3 % (w/v) with optimum growth at 0-1 % (w/v) NaCl. Growth occurred at 20-42 °C (optimal growth at 30-37 °C) and pH 5.5-6.5 (optimal growth at pH 6.5). The 16S rRNA gene sequence similarity between strain KQZ6P-2T and its closest phylogenetic neighbour Paenibacillus chibensis JCM 9905T was 98.2 %. Phylogenetic analyses using 16S rRNA gene sequences showed that strain KQZ6P-2T formed a distinct lineage with Paenibacillus chibensis JCM 9905T. The draft genome of strain KQZ6P-2T was 5 937 633 bp in size and its DNA G+C content was 47.2mol%. Comparative genome analysis revealed that the average nucleotide identity, digital DNA-DNA hybridization and average amino acid identity values among strain KQZ6P-2T and its related species were below the cut-off levels of 95, 70 and 95.5%, respec-tively. The cell-wall peptidoglycan of strain KQZ6P-2T contained meso-diaminopimelic acid as the diagnostic diamino acid. Major cellular fatty acids were anteiso-C15:0 and C16:0. The polar lipids comprised diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, two unidentified aminophospholipids, four unidentified phospholipids, an unidentified aminolipid and five unidentified lipids. Based on phylogenetic, phenotypic and chemotaxonomic data, strain KQZ6P-2T represents a novel species of the genus Paenibacillus, for which the name Paenibacillus mangrovi sp. nov. is proposed. The type strain is KQZ6P-2T (=MCCC 1K07172T =JCM 34931T).

Desulfovibrio mangrovi sp. nov., a sulfate-reducing bacterium isolated from mangrove sediments: a member of the proposed genus "Psychrodesulfovibrio".

"Psychrodesulfovibrio", a proposed genus within the family Desulfovibrionaceae, is a group of sulfate-reducing bacteria with biogeochemical significance but restricted child taxa availability. In this study, a strictly anaerobic bacterium, designed strain FT415T, was isolated from mangrove sediments in Futian Mangrove Nature Reserve in Shenzhen, China. The strain was Gram-stain-negative, motile, and vibrio-shaped with a single polar flagellum, which grew at the temperature range of 15-42°C (optimum 37°C), pH range of 6.0-7.5 (optimum 6.8), and in the presence of 0-36gl-1 NaCl (optimum 6gl-1 NaCl). In the presence of sulfate, electron donors including lactate, ethanol, pyruvate, malate, fumarate, succinate, cysteine, and glycerol were incompletely oxidized to acetate, and H2 and formate were used as electron donors with acetate as the carbon source by strain FT415T. Sulfate, thiosulfate, sulfide, and anthraquinone-2,6-disulfonate were reduced in the presence of lactate. Fe(III) oxide was reduced without cell growth. Fermentative growth was observed with pyruvate and cysteine. Vitamins were not required for growth. The major cellular fatty acids (> 10%) were C16:0, summed feature 10 (C18:1 c11/t9/t6 and/or unknown ECL 17.834), C16:1 cis 9, and C18:0. The major polar lipids were phosphatidylethanolamine, phospholipids, and aminolipids. The predominant menaquinone was MK-6(H2). The genomic DNA G+C content was 56.7%. Phylogenetic analysis showed that strain FT415T shared a 98.1% similarity in 16S rRNA gene sequence, an average nucleotide identity value of 84.0%, an average amino-acid identity value of 85.4%, and a digital DNA-DNA hybridization value of 25.7% with its closest relative Desulfovibrio subterraneus HN2T, which has been proposed to be transferred to the genus "Psychrodesulfovibrio". Based on phenotypic, phylogenetic, and genotypic evidence, a new species of the family Desulfovibrionaceae, Desulfovibrio mangrovi sp. nov. was proposed with the type strain FT415T (=GDMCC 1.3410T=KCTC 25525T).

Microplastic occurrence in finfish and shellfish from the mangroves of the northern Gulf of Oman

This study was conducted to assess microplastic (MP) pollution in some aquatic animals inhabiting planted and natural mangrove swamps in the northern Gulf of Oman. The KOH-NaI solution was used to retrieve MPs from the gastrointestinal tracts of animals. The highest MP prevalence was recorded in crabs (41.65 %) followed by fish (33.89 %) and oysters (20.8 %). The abundance of MPs in examined animals varied from zero in Sphyraena putnamae to 11 particles in a Rhinoptera javanica specimen. When polluted-only animals were considered, the mean abundance of MPs significantly varied among species and between locations. The mean density of ingested MPs was higher in the planted mangrove animals (1.79 ± 2.89 vs. 1.21 ± 2.25 n/individual; mean ± SD). Among the examined fish species, R. javanica ingested the highest number of MPs (3.83 ± 3.93 n/individual; mean ± SD). The polyethylene/ polypropylene fragments or fibers of average 1900 μm size were recorded as predominant (>50 % occurrence) MP particles.

Mangrove and microplastic pollution: A case study from a small island (Mauritius)

Marine sediments have been demonstrated to be a long-term sinks for microplastics and their contamination in mangrove sediment are of no exception with relatively scarce information available globally. This work aimed to determine the prevalence of microplastics in two natural mangrove forests of a small island developing state, Mauritius, with emphasis on the proximity of human settlement and anthropogenic activities. Sediments were collected in triplicates monthly from October to December 2018 at Ferney (remote site) and Mahebourg (populated site) in three tidal zones: seaward (Z1), middle (Z2) and landward zone (Z3). Microplastics retrieved were classified in terms of shape and size classes. Results showed the presence of microplastics in all sediment samples with average abundance of 107.4 ± 76.42 particles kg −1 at Ferney and 140.2 ± 85.38 particles kg −1 at Mahebourg. Average microplastics abundance was highest in the ZI and Z3 tidal zones and least in Z2 at Ferney and Mahebourg respectively. Majority of microplastics recovered were in the size class 800–1000 μm and 1000–2000 μm, and in the fragment and film shape that may be derived from the fragmentation of larger plastic debris. This study is an important baseline for mangrove protection as it provides a better understanding of microplastics pollution status and information for future planning of management strategies on a local and regional scale.

Population Structure of Parasesarma brevicristatum and Parasesarma semperi as an Indicator of Mangrove Replanted Forest Condition in Bintuni Bay, Indonesia

The mangrove forest at Bintuni Bay is one of the largest in Indonesia, and a portion of it is being used as production forest to produce woodchips. Replanting in the production forest results in various ecosystem conditions through ages. Since the Sesarmidae crab is an important component of the mangrove ecosystem and contributes significantly to its energy cycle, it is frequently used as a bioindicator to evaluate the ecosystem’s health. In the production mangrove area of Perseroan Terbatas Bintuni Utama Pure Wood Industries, sampling was done using the purposive sample method with circular plots in natural mangrove forests, replanted trees aged 25 and 5 years, and forests that had just been harvested. According to the survey, station 3′s five-year-old replanting of P. brevicristatum and P. semperi crabs had a population density of 139,455 Ind.ha−1 while station 4′s damaged forest had a population density of 119,047 Ind.ha−1. Both varieties of crabs have a higher male to female sex ratio. It was discovered that young individuals dominated the two species of crabs’ size distribution. Both species of crabs’ length weight relationships displayed a positive allometric tendency. The density of the saplings was the element of the mangrove vegetation that had the greatest impact on the population structure of both crabs.

Korelasi indeks keanekaragaman dan kerapatan tegakan dengan simpanan karbon mangrove Estuari Perancak

Land use change is a huge threat for mangrove ecosystems,which are known for their high carbon sequestration and storage capacity.Vegetation restoration efforts are often undertaken, but fail to restore optimal ecosystem carbon sequestration. The mangrove forest of Perancak Estuary with a history of restoration project was made the subject of this research. The objectives include: (i) estimation of mangrove biomass and sediment carbon stock; (ii) comparison of restored, mixed and natural mangroves’ total carbon stock; (iii) correlational analysis between stand density and diversity indices with ecosystem carbon stock. Nine sampling points were determined within three mangrove categories (mixed, natural, restored). Stand characteristics and diameter at breast height (DBH) were measured to allometrically estimate biomass carbon. Sediment carbon was analyzed with Loss on Ignition (LOI) method. Correlational analysis was done with Pearson’s correlation coefficient. Total ecosystem carbon stock is 4472,93 tonnes ha-1 (biomass C: 4046,31 tonnes ha-1; sediment C: 426,62 tonnes ha-1). Highest carbon stock value was found on restored mangroves due to high contribution of sediment C offsetting its low biomass C. Lowest carbon stock value was found on natural mangroves due to decreased root biomass production and increased decomposition due to change in tidal regimes. There is a strong positive correlation between stand density and biomass carbon. Simpson index of diversity has a stronger (though non significant) correlation with biomass carbon than Shannon-Wiener index.

Phytoplankton Diversity as a Bioindicator of Water Quality Mangrove Ecosystems in Clungup Mangrove Conservation, Kondang Merak and Sempu Island, Malang Regency

Local community groups have handled damage to the mangrove ecosystem on the coast of South Malang by carrying out restoration. The purpose of this study was to evaluate water quality in the restoration mangrove ecosystem based on phytoplankton diversity as bioindicators. A water and phytoplankton sampling was repeated three times with a depth of about 10-15 cm (below the surface water) at each location consisting of 4 restored mangrove ecosystems in Clungup Mangrove Conservation (CMC) and Kondang Merak as well as one natural mangrove ecosystem in Teluk Semut, Sempu Island, Malang Regency. Water quality parameters include water temperature, air temperature, conductivity, pH, Dissolved Oxygen (DO), Biochemical Oxygen Demand (BOD), nitrate, and orthophosphate content. The biotic index includes the Trophic Diatom Index (TDI) as an indicator of water nutrient content and Percentage Pollution Tolerance Value (%PTV) as an indicator of organic pollution. The water quality in the five mangrove ecosystems of CMC, Kondang Merak, and Teluk Semut has met the water quality standard for marine biota except for DO, nitrate, and orthophosphate content in several locations. Water quality in five mangrove ecosystems CMC, Kondang Merak, and Teluk Semut based on phytoplankton indicators did not show any contamination with toxic materials (H’). Based on TDI, it is categorized as eutrophic – hypereutrophic, except at the reference site of Teluk Semut mangrove; based on PTV polluted with moderate to high organic matter except at the reference site locations, namely Teluk Semut, and CMC 2. Thus, a location that has good phytoplankton bioindicators is Teluk Semut.

Bacillus litorisediminis sp. nov., a Thermophilic Bacterium Isolated from Mangrove Sediment.

Two aerobic, Gram-staining-positive, rod-shaped, endospore-forming, thermophilic bacterial strains, designated FJAT-47801T and FJAT-47835, were isolated from the sediment collected from Zhangjiang Estuary Mangrove National Nature Reserve in Fujian Province, China. Growth was observed at 25-55°C (optimum, 50°C) and pH 7.0-9.0 (optimum, pH 7.0), with up to 4.0% (w/v) NaCl (optimum, without NaCl). Strains FJAT-47801T and FJAT-47835 showed the highest 16S rRNA gene sequence similarity to Bacillus oleivorans (98.5%). The 16S rRNA gene sequence similarity between FJAT-47801T and FJAT-47835 was 99.9% indicating they were the same species. Phylogenetic (based on 16S rRNA gene sequences) and phylogenomic (based on 120 conserved bacterial single-copy genes) trees showed that strains FJAT-47801T and FJAT-47835 should be affiliated to the genus Bacillus. The of menaquinone of strain FJAT-47801T was MK-7. The major fatty acids of strain FJAT-47801T were iso-C15:0, anteiso-C15:0, iso-C17:0, and C16:0. The major polar lipids strain FJAT-47801T were phosphatidylethanolamine (PE), diphosphatidylglycerol (DPG), and phosphatidylglycerol (PG). The genomic DNA G+C content of strain FJAT-47801T was 39.3%. The average nucleotide identity (84.3%) and the digital DNA-DNA hybridization value (28.1%) between strain FJAT-47801T and B. oleivorans CCTCC AB 2013353T were below the cut-off level for species delineation. Based on the above results, strain FJAT-47801T represents a novel species of the genus Bacillus, for which the name Bacillus litorisediminis sp. nov., is proposed. The type strain is FJAT-47801T (=GDMCC 1.2712T = JCM 34875T).