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This study identified 260 lanternfish larvae specimens belonging to 20 species from 12 genera, which were obtained from 544 samples of the Ninety East Ridge waters in the Indian Ocean using the COI DNA barcoding. Among the samples, the intra-specific genetic distances ranged from 0% to 2.99%, while inter-specific genetic distances ranged from 1.88% to 25.71%. With the exception of Notolychnus valdiviae, the maximum intra-specific genetic distances were lower than the minimum inter-specific genetic distances for all species. The haplotypes of nine species were analyzed, revealing significant differences in the number, structure, and spatial distribution patterns. Notably, Ceratoscopelus warmingii and Notolychnus valdiviae displayed a significant north-south divergence pattern. The results indicated that seamount topography may influence the gene flow and horizontal distribution patterns of some lanternfish species, as shown by the distribution patterns of different populations of some species.

Environmental context Methane and nitrous oxide play a significant role in climate change, while the variation in fluxes in mangrove-dominated coastal wetlands is a key uncertainty in the production of these gases. Field studies measuring the fluxes of these gases in a specific coastal mangrove were conducted and revealed complex seasonal behaviors. Methane emissions to the atmosphere were significant, while nitrous oxide emissions were less so, but are likely to increase where nutrient levels increase. Abstract Mangroves are carbon sinks that are believed to contribute to carbon neutrality; however, they are also considered to be partly offset by their emissions of methane (CH4) and nitrous oxide (N2O). In this study, dissolved CH4, N2O and other hydrological parameters over the tidal cycle in the Golden Bay mangrove (GBM), Beihai, Guangxi, are investigated during the dry season and wet season. The concentration and flux of dissolved N2O and CH4 in the GBM have distinct seasonal variations under the influence of the tidal cycle, and the concentration and flux in the dry season were higher than those in the wet season, with GBM as a weak source of N2O and a strong source of CH4. The fluxes of N2O and CH4 were 119 ± 370 μmol m−2 yr−1 and 87.2 ± 48.6 mmol m−2 yr−1 respectively during tidal coverage. The emission of CH4 through the water–atmosphere interface offsets 22.5 % of the total carbon sequestration of GBM. Owing to the potential increase in N2O emissions caused by possible exogenous nitrogen input and the transport of dissolved CH4 from mangroves to coastal water, uncertainty remains in assessing the capacity of blue carbon sinks in mangroves.

In 2003, Kandelia obovata was identified as a new mangrove species differentiated from Kandelia candel. However, little is known about their chloroplast (cp) genome differences and their possible ecological significance. In this study, 25 whole cp genomes, with seven samples of K. candel from Malaysia, Thailand, and Bangladesh and 18 samples of K. obovata from China, were sequenced for comparison. The cp genomes of both species encoded 128 genes, namely 83 protein-coding genes, 37 tRNA genes, and eight rRNA genes, but the cp genome size of K. obovata was ~2 kb larger than that of K. candle due to the presence of more and longer repeat sequences. Of these, tandem repeats and simple sequence repeats exhibited great differences. Principal component analysis based on indels, and phylogenetic tree analyses constructed with homologous protein genes from the single-copy genes, as well as 38 homologous pair genes among 13 mangrove species, gave strong support to the separation of the two species within the Kandelia genus. Homologous genes ndhD and atpA showed intraspecific consistency and interspecific differences. Molecular dynamics simulations of their corresponding proteins, NAD(P)H dehydrogenase chain 4 (NDH-D) and ATP synthase subunit alpha (ATP-A), predicted them to be significantly different in the functions of photosynthetic electron transport and ATP generation in the two species. These results suggest that the energy requirement was a pivotal factor in their adaptation to differential environments geographically separated by the South China Sea. Our results also provide clues for future research on their physiological and molecular adaptation mechanisms to light and temperature.

Although evidence suggests the ubiquity of meso- and microplastics (MMPs) in mangrove forests, our knowledge of their bioavailability and risk on mangrove leaves is scarce. Here, we investigated MMP contamination concerning submerged mangrove leaves and herbivorous snails that mainly feed on them from the four mangrove forests located in Beibu Gulf, Guangxi Province, China. Results showed that the MMP abundance on the mangrove leaves ranged from 0.01 ± 0.00 to 0.42 ± 0.15 items cm

Habitat loss and degradation of mangrove forests can be caused by both sea level rise (SLR) and unsustainable land practices. Current long-term change projections are often based on changes to mangrove extent; however, this may overlook fragmentation and the associated habitat resilience decline and therefore fail to adequately reveal the risks to mangrove habitats. A mangrove sustainability index (MSI) was proposed in this study to assess the impact of SLR and land use on mangrove habitats. The index consists of four components: habitat area change, habitat quality, landscape pattern, and protection ratio. Ecological models and landscape models were combined to calculate the MSI. Considering the SLR under RCP4.5 and RCP8.5 and land use strategies, four scenarios were set with prediction periods of base year (2020) to 2050 and 2100. The Leizhou Peninsula, China was used as the case study. The results showed that dual stressors would reduce the extent of mangroves by 16.6%-56.2%. Habitat quality was sensitive to land use change but was not affected by SLR. Landscape pattern and protection ratio were influenced by SLR but less effected by land use. In all scenarios, mangroves tended to migrate out of the protected areas, with protection ratio decreasing from 37% to 16.9%-29.9%. Newly expanding habitats may suffer from patch fragmentation and low connectivity. Unsustainable mangrove distribution sites on Leizhou Peninsula were identified as hotspots for management. Projections under different scenarios showed that some unsustainable sites could be reversed to sustainable sites through improvements in land use policies. The proposed approach could provide essential tools for the formulation of mangrove conservation and restoration strategies adapted to climate change.

Flyingfishes of the family Exocoetidae are sometimes difficult to identify solely based on morphology as members of certain genera share overlapping characteristics. Combining morphological and molecular analyses, the present study reports two specimens of stained flyingfish Cheilopogon spilonotopterus (Bleeker 1865) from the northern Bay of Bengal. As for COI gene sequences, nucleotide variations at five different positions (576 nucleotides identical out of 581 bp) were noted between two specimens of C. spilonotopterus and K2P genetic distances for all conspecific sequences ranged 0.000–0.050. The results of DNA barcoding, therefore, support the validity of both specimens as C. spilonotopterus at genetic level. These are the first DNA barcode records of C. spilonotopterus from the northern Bay of Bengal region.

Exosomes derived from human umbilical cord mesenchymal stem cells (hucMSCs) expressing microRNAs (miRNAs) have been highlighted in human cancers. However, the detailed molecular mechanism of hucMSCs-derived exosomal miR-451a on hepatocellular carcinoma (HCC) remains further investigation. Our study aims to explore the impact of exosomal miR-451a on the progression of HCC. Expression of miR-451a and a disintegrin and metalloprotease 10 (ADAM10) in HCC tissues and adjacent normal tissues were determined. The exosomes were extracted from hucMSCs and co-cultured with Hep3B and SMMC-7721 cell lines. After the treatment of relative exosomes or exosome inhibitor GW4869 in Hep3B and SMMC-7721 cells, the paclitaxel resistance and malignant phenotypes of HCC cells were measured. Moreover, the effect of hucMSCs-derived exosomes on the expression of miR-451a and ADAM10 in HCC cells was assessed. The targeting relationship between miR-451a and ADAM10 was verified to detect the impact of ADAM10-wild type and ADAM10-mutant type (MUT) on HCC cell processes. Low expression of miR-451a and high expression of ADAM10 indicated a poor prognosis of HCC patients. MiR-451a was up-regulated while ADAM10 was down-regulated in HCC cells after co-culture with HucMSC-derived exosomes. The exosomes elevated miR-451a and inhibited ADAM10 to suppress the paclitaxel resistance, cell cycle transition, proliferation, migration and invasion, and promote apoptosis of HCC cells. ADAM10 was verified to be a target gene of miR-451a. ADAM10-MUT promoted HCC process independent of miR-451a mimic. HucMSC-derived exosomal miR-451a could restrict the epithelial–mesenchymal transition of HCC cells by targeting ADAM10, which might provide new targets for HCC treatment.

The stable isotope ratios of nitrogen (δ15N) and carbon (δ13C) were applied in this study to analyze sediment carbon sources and primary food sources of epifauna in an oceanic mangrove forest in tropical North Sulawesi, Indonesia. Proportional contribution of mangrove-derived carbon to the food sources was compared among epifauna belonging to different feeding guilds. The sediment in the mangrove site with a depleted δ13C signature (−28.02‰±0.24‰) mainly consists of mangrove-derived carbon. Analysis using Bayesian stable isotope mixing model in the R program shows that mangrove-derived carbon can dominate the food sources of a majority of the epifauna (11 out of the total 18 species), especially 2 sesarmid crabs Parasesarma semperi and Sesarma sp., crab Epixanthus dentatus, and snails Terebralia sulcata and Optediceros breviculum, which belong to various feeding guilds. Mangrove-derived carbon has a proportional contribution to the food sources of fiddle crab Tubuca coarctata and 3 littorinid snails (Littoraria spp.) close to that of suspended particulate organic matter. Three planktophagous bivalve species (Anadara antiquata, Anadara sp. and Callista erycina) were found to mainly feed on seagrass-derived materials. Mean proportional contributions of mangrove-derived carbon to the food sources were 50.15%, 59.60%, 46.20% and 27.58% for the carnivorous, omnivorous, phytophagous and planktophagous groups, respectively. The results suggest that mangrove-derived carbon can directly (via grazing plant tissues) or indirectly (via deposit feedings) make an important contribution to the food sources of epifauna in the oceanic mangrove forest where the allochthonous input of organic carbon is low.

The Ovulidae (Gastropoda, Cypraeoidea) is a family of small to medium Mollusca in the order Littorinimorpha, and

Two bacterial strains, designated as 1-4-3T and 1-4-4, were isolated from a mangrove sediment cultured with coastal seawater. The cells were Gram-stain-negative, motile, short, rod-shaped bacteria with flagella. Growth occurred at 4–37 °C, pH 7.0–9.0, and 0–7% NaCl. The predominant fatty acids of the novel strains were C18 : 1 ω7c, C19 : 0 cyclo ω8c, C18 : 0, and C16 : 0. A phylogenetic analysis based on 16S rRNA gene sequences and whole genome phylogeny analysis based on distance matrix revealed an affiliation between the two strains and the genus Aureimonas , with closest sequence similarity to A. populi 4M3-2T (96.41 and 96.64% similarity, respectively) and A. glaciistagni (96.01 and 96.23% similarity, respectively). The DNA G+C content of strain 1-4-3T was 66.80 mol%. Strain 1-4-3T displayed low DNA–DNA relatedness to A. populi 4M3-2T, with an average nucleotide identity value of 77.47 % and digital DNA–DNA hybridization value of 22.83 %. Genotypic, chemotaxonomic, and phenotypic data indicate that strains 1-4-3T and 1-4-4 represent a novel species of the genus Aureimonas , for which we propose the name Aureimonas mangrovi sp. nov. The type strain is 1-4-3T (=LMG 31693T=CGMCC 1.18507T).

Drug resistance is still a major obstacle for efficient treatment of hepatocellular carcinoma (HCC) during the cisplatin-based chemotherapy. Recent studies have demonstrated that CD133 positive population of cancer cells are responsible for multiple drug resistance. We are supposed to take strategies to sensitize CD133+ HCC cells to cisplatin treatment. In the present study, CD133+ HCC cells showed significant cisplatin-resistance compared to the CD133- HCC cells. Downregulation of miR-124 was observed in CD133+ HCC cells. However, enforced expression of miR-124 can increase the sensitivity of CD133+ HCC cells to cisplatin treatment in vitro and in vivo. Mechanically, overexpression of miR-124 was found to inhibit the expression of SIRT1 and thus promoted the generation of ROS and phosphorylation of JNK. As the results, overexpression of miR-124 expanded the apoptosis in cisplatin-treated CD133+ HCC cells. We then demonstrated that overexpression of miR-124 sensitized cisplatin-induced cytotoxicity against CD133+ hepatocellular carcinoma cells by targeting SIRT1/ROS/JNK pathway.

Global mangrove forests have exhibited distinct changes in the past decades owing to anthropogenic activities, with land-use pressure being among the main causes of mangrove loss. Thus, understanding the inherent conflicts between conservation/restoration and land-use demands is fundamental for mangrove management. To predict how land-use changes will drive the spatiotemporal patterns of mangrove habitats, a novel integrated framework coupling MaxEnt and Dyna-CLUE modeling was proposed. The coupled model can identify suitable mangrove afforestation habitats and predict the impact of land-use change on potential mangrove habitats. In this study, the model was used to predict the mangrove habitat change in 2030 in the province with the most mangrove forests in China. The potential suitable habitat of 14 mangrove species under three coastal land-use scenarios were mapped using the coupled model. Under the current trend scenario, only 41.2% of the existing wetland would be retained, whereas the potential distribution area of all the mangrove species will decrease by an average of 30%. Under the sustainable development and ecological protection scenarios, the mangrove habitat could be increased by 11% to 61%, depending on the species. Different mangrove species showed varied sensitivity to the improved land-use policies, with several species being harder to restore than others, even under aggressive protection and restoration policies. The combined use of both MaxEnt and Dyna-CLUE models proved complementary and offered insights into the impacts of different land-use policies on the spatiotemporal change of mangrove habitats.

The Ovulidae are the most ecologically diverse family of the order Littorinimorpha. And the Sandalia is a small genus containing only three species. In the present study, we collected 44 specimens of Ovulidae (Gastropoda: Cypraeacea), belonging to six genera and eight species, including 20 Sandalia bridgesi and 2 Sandalia triticea individuals. The cytochrome c oxidase I gene (COI), 16S rRNA, and ITS1-5.8S-ITS2 sequences were obtained from the specimens and compared with sequences downloaded from GenBank to calculate genetic distances and construct phylogenetic trees. The sequences of S. bridgesi and S. triticea exhibited a high degree of similarity, and the S. bridgesi does not formed a separate clade, supporting the proposition that S. bridgesi should be considered a synonym of S. triticea.

Blue Carbon (BC) strategy refers to the approaches that mitigate and adapt to climate change through the conservation and restoration of seagrass, saltmarsh and mangrove ecosystems and, in some BC programs, also through the expansion of seaweed aquaculture. The major losses of coastal habitats in combination with the commitments of China under the Paris Agreement provide unique opportunity and necessity to develop a strong Chinese BC program. Here, we (1) characterize China's BC habitats, examine their changes since 1950 along with the drivers of changes; (2) consider the expansion of seaweed aquaculture and how this may be managed to become an emerging BC resource in China, along with the engineering solutions required to enhance its potential; and (3) provide the rationale and elements for BC program in China. We find China currently has 1326–2149 km2 wild and 2–15 km2 created mangrove, saltmarsh and seagrass habitats, while 9236–10059 km2 (77–87%) has been lost since 1950, mainly due to land reclamation. The current area of farmed seaweed habitat is 1252–1265 km2, which is close to the area of wild mangrove, saltmarsh and seagrass habitats. We conclude that BC strategies have potentials yet to be fully developed in China, particularly through climate change adaptation benefits such as coastal protection and eco-environmental co-benefits of seaweed farming such as habitat creation for fish and other biota, alleviation of eutrophication, hypoxia and acidification, and the generation of direct and value added products with lower environmental impact relative to land-based production. On this basis, we provide a roadmap for BC strategies adjusted to the unique characteristics and capacities of China., This research was funded by the Program of International Science & Technology Cooperation, the Ministry of Science and Technology of China (grant # 2015DFA01410,Bioremediation of polluted coastal water and carbon sequestration) and Zhejiang Provincial Department of Science and Technology (2016C04004).

Mangrove forests support numerous ecosystem services and contribute to coastal ecological risk reduction. However, they are one of the most severely threatened ecosystems in the world. China has carried out national mangrove restoration projects, but there is still insufficient scientific information for the strategic planning of this restoration. In this study, we carried out mangrove suitability assessments using the genetic algorithm for rule-set prediction (GARP) and maximum entropy (MaxEnt) models, and we mapped the restoration potential of mangrove forests in China for the first time. The restoration potential index (RPI), which combines suitability and land use data, is proposed as a rapid estimator method for locating theoretically available areas for restoration. The results showed that the MaxEnt model performed better than GARP in predicting potential mangrove distributions. Temperature was the most important environmental factor for determining large scale distribution of mangroves. The predicted northern limit of mangrove distribution was around 28°27′ N–28°35′ N. Using the RPI approach, 16,800 ha with the potential to restore mangrove forests was identified. According to both models, the largest area with restoration potential occurs along the Guangdong and Guangxi coast. Nationwide, about 75% of the potential area suitable for mangrove forests has been lost as a consequence of land use and is no longer available for restoration. Around 6400 ha of ponds is currently used for aquaculture, accounting for 38% of theoretically restorable areas. These areas can be a priority for mangrove forest restoration. In conclusion, our findings provide a better scientific understanding of mangrove distribution in China and can underpin strategic design and planning of mangrove restoration.

The present study compared the ecosystem organic carbon (OC) stocks and soil OC sources between two 12-year-old monospecific mangrove sites comprised of different species (Kandelia obovata in tree form and Aegiceras corniculatum in shrub form). We tested whether the carbon sequestration performance following rehabilitation varied with plantation of species in different forms and whether mangrove vegetation sequestrate OC more rapidly than soil pool. The results showed that mangrove rehabilitation increased the ecosystem OC stock relative to that of a non-vegetated bare flat. The accumulation of soil carbon was accompanied by increased soil total nitrogen contents and decreased δ13C values of soil OC, indicating that the increases in OC and TN contents were a function of accumulation of 13C-depleted mangrove materials in the soil. The sequestrated OC over the 12 years was considerably less in soil than in biomass at each mangrove site, suggesting that mangrove vegetation contributes more rapidly than the soil to ecosystem OC sequestration following rehabilitation before the vegetation has reached maturity. Compilation of the carbon stocks from worldwide rehabilitated mangrove forests with various ages further supports this finding. The K. obovata site had an apparently higher biomass OC stock but less OC in the soil than those at the A. corniculatum site. There was a higher standing leaf litter stock on the forest floor and more mangrove materials incorporated into the top 15 cm soil at the A. corniculatum site. These results suggested that the two rehabilitated mangrove sites had different development trajectories of both biomass and soil OC sequestration. Moreover, the performance of ecosystem carbon sequestration was related to plantation of different mangrove species. These carbon sequestration feature of rehabilitated mangrove forests therefore deserve attention in future rehabilitation programs to promote carbon sequestration performance.

Mangroves are important wetland ecosystems on tropical and subtropical coasts. There is an urgent need to better understand how the spatial distribution of mangroves varies with climate change factors. Species distribution models can be used to reveal the spatial change of mangroves; however, global models typically have a horizontal resolution of hundreds of kilometers and more than 1 km, even after downscaling. In the present study, a maximum entropy model was used to predict suitable areas for the northernmost mangroves in China in the 2050s. An approach was proposed to improve the resolution and credibility of suitability predictions by incorporating land-use potential. Predictions were made based on two CMIP6 scenarios (i.e., SSP1-2.6 and SSP5-8.5). The results show that the northern edge of the natural mangrove distribution in China would migrate from 27.20° N to 27.39° N–28.15° N, and the total extent of suitable mangrove habitats would expand. By integrating 30 m resolution land-use data to refine the model’s predictions, under the SSP1-2.6 scenario, the suitable habitats of mangroves are predicted to be 13,435 ha, which would increase by 33.9% compared with the current scenario. Under the SSP5-8.5 scenario, the suitable area would be 23,120 ha, with an increased rate of 96.5%. Approximately 40–44% of the simulated mangrove patches would be adjacent to aquacultural ponds, cultivated, and artificial land, which may restrict mangrove expansion. Collectively, our results showed how climate change and land use could influence mangrove distributions, providing a scientific basis for adaptive mangrove habitat management despite climate change.

Recent studies have highlighted the valuable role played by mangrove forests in carbon sequestration and storage. Although Indonesia accounts for a large proportion of global mangrove area, knowledge on the carbon stock and sources in the Indonesian mangrove is still limited. In this study, we quantified the ecosystem organic carbon (OC) stock and its spatial variation at an oceanic mangrove in Wori, North Sulawesi, Indonesia. The sources of soil OC were also investigated. The results showed that the mangrove soil had a substantial OC stock containing 15.4 kg/m2 (calculated by carbon) in the top 50 cm soil, and represented the majority of the ecosystem OC stock at the Wori mangrove. The mangrove biomass and ecosystem OC stock were 8.3 kg/m2 and 23.7 kg/m2, respectively. There was no significantly difference in the soil OC stock among the stations with difference distances offshore, while the highest mangrove biomass OC stock was found at the seaward station. Isotope mixing calculations showed that the rich OC in mangrove soils was attributed to the accumulated autochthonous mangrove source while the suspended organic matter in tidal water and the mangrove-adjacent seagrass contributed less than 20% to the soil OC. The results further demonstrated the importances of the oceanic mangrove in carbon storage and the mangrove plants in contributing OC to their soils.