Concentration of Heavy Metals in Sediment and Seagrasses Tissue of the Red Sea Coastal Water of the Sudan

The study investigated the concentration of Lead, Cadmium, Nickels and Chromium in sediment and seagrass tissues at six selected sites along the Sudanese Red Sea coast. The findings of the study added some important and necessary information about the status and condition of the coastal environment in the Sudanese Red Sea coast in terms of the extent of pollution with heavy metals. The study sites included: Marsa Bashayer, Marsa Dama Dama, Green Area, Shipyard, Marsa Halout and Dungonab Bay. The Atomic Absorption Spectrophotometer was used to measure Lead, Cadmium and Nickels. The colorimetric detection method was used for Chromium using the Spectrophotometer. Marsa Dama Dama site revealed high levels concentration of heavy metals in sediment for Lead (60.5) μg/g, Cadmium (0.22) μg/g and Chromium (146.65) μg/g. Marsa Halout showed the highest mean concentration of Nickel in sediment at 14 μg/g. The variation of concentration of metals in sediment between the sites was not significant. The mean concentration of metals in seagrass species tissues ranged from 3.9 to 26.25 μg/g for Lead, 0.1 to 0.90 μg/g for Cadmium, 0.38 to 5.96 μg/g for Nickel and 0.15 to 0.495 μg/g for Chromium. The differences of concentration of heavy metals in seagrass tissues among the sites were significant for Lead and not significant for Cadmium;Nickel and Chromium.

Antifouling Activity of Bacterial Symbionts of Seagrasses against Marine Biofilm-Forming Bacteria

Marine biofouling has been regarded as a serious problem in the marine environment. The application of TBT and other heavy metal-based antifoulants has created another environmental problem. The present study explored the possible role of baterial symbionts of seagrasses Thalassia hemprichii, and Enhalus acoroides, which were successfully screened for antifouling activity against marine biofilm-forming bacteria isolated from the surrounding colonies of seagrasses. Bacterial symbionts were isolated and tested against biofilm-forming bacteria resulted in 4 bacterial symbionts capable of inhibiting the growth biofilm-forming isolates. Molecular identification based on 16S rRNA gene sequences revealed that the active bacterial symbionts belonged to the members of the genera Bacillus and Virgibacillus. Further tests of the crude extracts of the active bacterial symbionts supported the potential of these symbionts as the alternative source of environmentally friendly marine antifoulants.

Antibacterial potential of three seagrasses against human pathogens

Objective:To evaluate the antibacterial activity of Halophila stipulacea(H.stipulacea), Cymodocea serrulata(C.serrulata) and Halodule pinifolia(H.pinifolia) against seven human bacterial pathogens.Methods:The antibacterial activities of the extracts on the various test organisms using disc diffusion method and Minimum Inhibitory Concentraction(MIC).Results: Methanol and chloroform extracts of all the three seagrasses were active against all the tested pathogens,whereas the hexane extract of seagrasses was not active against Staphylococcus aureus (S.aureus).Antibacterial activity of three seagrass screened,was in the order of H.pinifolia 】 H.stipulacea.】 C.serrulata.Conclusions:This antibacterial studies can further investigated on seagrasses for purification of bioactive substance and its possible utility in disease control.

Assessing the potential for satellite image monitoring of seagrass thermal dynamics:for inter-and shallow sub-tidal seagrasses in the inshore Great Barrier Reef World Heritage Area,Australia

Seagrass meadows are at increasing risk of thermal stress and recent work has shown that water temperature around seagrass meadows could be used as an indicator for seagrass condition.Satellite thermal data have not been linked to the thermal properties of seagrass meadows.This work assessed the covariation between 20 in situ average daily temperature logger measurement sites in tropical seagrass meadows and satellite derived daytime SST(sea surface temperature)from the daytime MODIS and Landsat sensors along the Great Barrier Reef coast in Australia.Statistically significant(R2=0.787–0.939)positive covariations were found between in situ seagrass logger temperatures and MODIS SST temperature and Landsat sensor temperatures at all sites along the reef.The MODIS SST were consistently higher than in situ temperature at the majority of the sites,possibly due to the sensor’s larger pixel size and location offset from field sites.Landsat thermal data were lower than field-measured SST,due to differences in measurement scales and times.When refined significantly and tested over larger areas,this approach could be used to monitor seagrass health over large(106 km2)areas in a similar manner to using satellite SST for predicting thermal stress for corals.

Long-Term Persistence of Propeller and Anchor Damage to Seagrass Canopy and Demersal Biodiversity in Puerto Rico

Seagrass ecosystems support high biodiversity and productivity and constitute critical links to adjacent ecosystems. However, there is a growing concern that increasing recreational navigation may affect its ecological processes and functions, which may affect its recreational and tourism values, compromising local economies and livelihoods. The long-term impacts (1996-2011) of recreational navigation on seagrass benthic community structure were assessed by addressing the question of whether long-term effects of recreational navigation had a significant impact on seagrass community structure and on its benthic faunal assemblages. Findings evidenced: 1) a consistent spatio-temporal gradient in the ecological conditions of seagrasses across the scoured areas, with increased percent seagrass cover, density and canopy height, and seagrass benthic biodiversity with increasing distance from disturbed areas;2) a decline in percent seagrass cover, and an increased macroalgal and cyanobacterial percent cover through time around the disturbed areas;3) a significant shift in seagrass assemblage biodiversity as a response to boating that followed the intermediate disturbance hypothesis;4) an adverse effect on the spatial distribution and survival of multiple benthic invertebrate taxa;and 5) a significant decline in cnidarians, echinoids, ophiuroids, holothurians, and gastropods, and an increase in polychaetes, platyhelminths, and hermit crabs, particularly in areas exposed to boating. Spatio-temporal variation in seagrass community structure explained the observed variation in benthic faunal assemblages. The long-term consequences on ecosystem functions and management needs are discussed to foster the conservation of seagrasses.

Bioactive natural products from marine angiosperms:abundance and functions

This review explores the natural products of seagrass that are to be exploited for their bioactive potential.Beside from portraying the presence of a wide array of secondary compounds such as phenols,flavonoids,sterols and lipids from different seagrass species,the focus is on novel natural products projecting towards their biological applications.Though there are a significant number of reports on the abundance of secondary metabolites from seagrass and their bioactive derivatives,only a small number of reports explore their functional and defensive characteristics.Efforts have been made to collate the available information on seagrass natural products and clarify their function and metabolic pathway’s.It is emphasized that metabolic profiling of seagrass should be extensively progressed to obtain a deeper knowledge about the specific roles of each natural product.The investigation of seagrass natural products for their bioactive potential would most likely result in the detection of surprising and unexpected novel chemical structures and clinical leads that may be useful to mankind.

An ecological survey of the abundance and diversity of benthic macrofauna in Indonesian multispecific seagrass beds

Seagrasses are one of the most productive ecosystems in coastal areas and support a wide variety of associated fauna. The tropical Indo-Pacific region is considered to have the highest diversity of seagrass plant species and the largest distribution areas of seagrass, yet the seagrass macrofauna in this region are poorly understood. To help fill this gap in our knowledge, an ecological survey was conducted to describe the abundance and diversity of benthic macrofauna from tropical seagrass beds and to determine between-station variations within a transect and between-site variations in macrofaunal abundance, taxa richness and community structure. Benthic macrofaunal samples associated with seagrass beds were collected with a core sampler on the east coast of North Sulawesi in May 2014 and on the west coast in October 2015. A total of 149 species from 14 higher taxa was collected. The most species-rich groups were polychaetes（56 species, 26% of total individual numbers）, decapods（20 species, 9% of total numbers） and amphipods（18 species, 35% of total numbers）. Between-station variations within a transect displayed different patterns between the east coast and the west coast. On the east coast, there were marked variations in abundance between stations within a transect for the macrofauna and amphipod assemblages. Both taxa richness and abundance varied with station for the macrofauna and polychaete assemblages on the west coast, resulting from the heterogeneity of the substrate along a transect. One-way ANOSIM together with MDS ordination indicated that macrofaunal community structure in seagrasses differed significantly between the east coast and the west coast, corresponding with the division of seagrasses into two broad categories of habitats, i.e.,mangrove-seagrass-reef continuum and seagrass-reef continuum. Compared with other studies in tropical areas,the abundance and diversity of benthic macrofauna in the present study were moderate. The reason for the two markedly distinct macrofaunal communities might be attributed to multiple factors, including sediment pattern,seagrass structure and temporal changes.

Impacts of Typhoons Tianying and Dawei on seagrass distribution in Xincun Bay,Hainan Province,China

More than 50% of the typhoons landing in China have landed on the southeast coast, where they have caused great pressure on the coastal environment. Seagrass, one of the most important con- stituents of coastal ecosystems, is also greatly affected by typhoons. In order to clarify how seagrass distribution variation is affected by typhoons in coastal areas in southeast China, data of Typhoons Dawei and Tianying （category 4 and category 2 respectively, which just ran through the southern part of Hainan province） have been studied. In situ observation and satellite remote sensing data （CBERS-China Brazil Earth Resources Satellite） in 2004 and 2006 were used to retrieve seagrass distribution in Xincun Bay, Hainan province. In situ observations showed that leaf length, stem biomass and above ground biomass on average showed evidence of reduction after Typhoons Tiany- ing and Dawei. However, seagrass density showed no evidence of reduction after typhoon Tianying and Dawei passed by and increased rapidly in January 2006. From results of satellite remote sensing data, seagrass distribution can be detected with high accuracy, and the area of seagrass distribution on the south coast of Xincun Bay in 2006 after the typhoon passed by was smaller than that in 2004 in region A and B. However, in region C, area of seagrass coverage under 20% increased. These results demonstrated that typhoons Tianying and Dawei damaged seagrass bed and helped seagrass to get rid of aged and dead leaves, and this correspondingly facilitated seagrass growth.

The origin of the suspended particulate matter in the seagrass meadow of tropical waters, an evidence of the stable isotope signatures

Suspended particulate matter(SPM) has been known as an important variable in the organic matter flow of coastal ecosystem. Half of burial carbon in seagrass meadows is contributed by allochthonous sources that compose the SPM such as phytoplankton, seagrass detritus, marine snow aggregates and terrestrially derived particles. Each composition of the SPM contributes different roles and is important to be identified, for instance,the exact contribution of seagrass detritus will be useful for determination of carbon export through the detritus form in seagrass meadows. Here, the SPM of seagrass meadows is studied in Bintan Island and the Selayar Archipelago. The aim of this research is to determine the source origin of the SPM using a stable isotope signature.In order to fulfill this aim, the objectives are defined as:(1) to specify the stable isotope signature(δ13C and δ15N)of the SPM, and(2) to determine the proportional distribution of the SPM's prospectus sources. The result shows that the possibility of the source origin of the SPM includes a seagrass fraction(Enhalus acoroides and Thalassia hemprichii), terrestrial C4 plant, macroalgae, and terrestrial C3 plant. The SPM lies between the marine-and terrigenous-end members. However, it seems that the SPM is more to be terrigenous-end and allochthonous.According to a Bayesian mixing model, the terrestrial C4 has the highest contribution of the SPM at all sites except Barugaia and Pasi Island in Selayar(i.e., the highest contribution of the SPM is from the detritus of E. acoroides).The second contribution has been contributed by either seagrass detritus(E. acoroides or Th. hemprichii) or terrestrial C3 plant. The finding of this study indicates that there is a strong influence of the terrigenous sources in the SPM of the seagrass meadows.

Assessment of <i>Posidonia Oceanica</i>(L.) Delile conservation status by standard and putative approaches: the case study of Santa Marinella meadow (Italy, W Mediterranean)

The conservation status of the Posidonia oceanica meadow at Santa Marinella (Rome) was evaluated through both standard (bed density, leaf biometry, "A" coefficient, Leaf Area Index, rhizome production) and biochemical/genetic approaches (total phenol content and Random Amplified Polymorphic DNA marker). The bio-chemical/genetic results are in agreement with those obtained by standard approaches. The bed under study was ranked as a disturbed one, due to its low density, and high heterogeneity in leaf biometry, LAI values, "A" coefficient and primary production. This low quality ranking is confirmed by both mean phenol content in plants, quite high and scattered, and by the low genetic variability in the meadow, with a very high similarity of specimen at a local scale. Hence, these two putative approaches clearly identify the endangered conservation status of the meadow. They link plant biodiversity and ecophysiology to ecosystem 'health'. Furthermore, they are repeatable and standardizable and could be usefully introduced in meadows monitoring to check environmental quality.

Connectivity of fish assemblages along the mangrove-seagrasscoral reef continuum in Wenchang, China

Understanding the connectivity of fish among different typical habitats is important for conducting ecosystembased management, particularly when designing marine protected areas(MPA) or setting MPA networks. To clarify of connectivity among mangrove, seagrass beds, and coral reef habitats in Wenchang, Hainan Province,China, the fish community structure was studied in wet and dry seasons of 2018. Gill nets were placed across the three habitat types, and the number of species, individuals, and body size of individual fish were recorded. In total, 3 815 individuals belonging to 154 species of 57 families were collected. The highest number of individuals and species was documented in mangroves(117 species, 2 623 individuals), followed by coral reefs(61 species,438 individuals) and seagrass beds(46 species, 754 individuals). The similarity tests revealed highly significant differences among the three habitats. Approximately 23.4% species used two habitats and 11.0% species used three habitats. A significant difference(p<0.05) in habitat use among eight species(Mugil cephalus, Gerres oblongus, Siganus fuscescens, Terapon jarbua, Sillago maculata, Upeneus tragula, Lutjanus russellii, and Monacanthus chinensis) was detected, with a clear ontogenetic shift in habitat use from mangrove or seagrass beds to coral reefs. The similarity indices suggested that fish assemblages can be divided into three large groups namely coral, seagrass, and mangrove habitat types. This study demonstrated that connectivity exists between mangrove–seagrass–coral reef continuum in Wenchang area;therefore, we recommend that fish connectivity should be considered when designing MPAs or MPA network where possible.

Molecular diversity and biogeography of benthic microeukaryotes in temperate seagrass(Zostera japonica)systems of northern China

The productivity and health of seagrass depend on the combined inputs of nutrients from the water and sediments in which they grow and the microbiota with which they live intimately.However,little is known about the composition and diversity pattern of single-celled benthic eukaryotes in seagrass meadows.Here,we investigated how the structure and diversity of the benthic microeukaryotic community vary with respect to season,location,and seagrass colonization,by applying 18S rRNA gene amplicon sequencing for 96 surface sediment samples that were collected from three different seagrass habitats through four seasons.We found that benthic microeukaryotic communities associated with seagrass Zostera japonica exhibited remarkable spatial and seasonal variations,as well as differences between vegetated and unvegetated sediments.Diatoms and dinoflagellates predominated in the benthic microeukaryotic communities,but they were inversely correlated and displaced each other as the dominant microbial group in different seasons or habitats.Mucoromycota was more prevalent in vegetated sediments,whereas Lobulomycetales and Chytridiales had higher proportions in unvegetated sites.Total organic carbon and total organic nitrogen were the most important environmental factors in driving the microeukaryotic assemblages and diversity.Our study expands the available knowledge on the biogeographic distribution patterns and niche preferences for benthic microeukaryotes in seagrass systems.

Fish assemblages in seagrass habitat along the Jordanian coast of the Gulf of Aqaba

The spatial distribution and community structure of the fishes were studied at different depths and sites along the Jordanian coast in seagrass habitat. A total of 37,034 fishes were counted representing 132 species belonging to 35 families observed during visual census in three sites (average of 4741.6 fish per transect). Out of the 132 species encountered, 5 species of them including Neopomacentrus miryae Lethrinus borbonicus, Pseudanthias squamipinnis, Lethrinus variegatus, Siganus rivulatus accounted for 57.7% of all individuals. Fishes were most abundant and significantly higher at 12 m depths (mean N = 2889.6) in comparison with shallow 6m depth (mean = 1225.3 with (p = 0.0218). This may be attributed to many plank-tivorous fishes that inhabit this depth such as P. squampinnis, Paracheilinus octotaenia, Chromis pelloura, Decapterus macarellus, and Cirrhilabrus rubriventralis probably with high abundance of plankton at 12 m depth than 6 m. The number of species was significantly higher in Phosphate Loading Berth (PLB;mean S = 54.7) than in Hotels area site (HA;mean S = 12.8) with (p = 0.0002) and Tala Bay site (TB;mean S = 31) with (p = 0.0484). This may be due to higher hard coral cover at Phophate Loading Berth.

Biodiversity and seasonal variation of benthic macrofauna in Minicoy Island, Lakshadweep,India

From the Indian coast only limited data are available on the benthic fauna of the seagrass communities. In this study, seasonal variation in the distribution of macrobenthos and influence of environmental parameters was explored at four seagrass beds and two mangrove stations along the Minicoy Island, Lakshadweep, India, from September 1999 to August 2001. A total of 160 macrobenthic species from eight major groups represented the macrofauna of the Minicoy Island. Of the identified taxa, molluscs 70（gastropods 41.46%, bivalves 7.5%）, polychaetes 27（16.88%）, crustaceans 30（18.75%）, echinoderms 11（6.88%） and remaining others. Average seasonal abundance of benthic macrofauna ranged from 219 to 711 ind./m2, species diversity varied from 1.45 to 3.64 bits per individual, species richness index ranged from 4.01 to 26.17, evenness 0.69 to 1.66. In general, the higher abundance and species diversity was noticed in southern seagrass stations and northern seagrass stations, but in the mangrove stations comparatively low species diversity was observed. Three-way analysis of variance indicated that all communities resulted as being significantly different between seagrass and mangrove station, mainly when the seasonal interaction was considered. Multivariate analyses were employed to help define benthic characteristic and the relationship between environmental parameters at the six monitoring stations. Results of cluster analyses and multidimensional scale plot suggest that for mangrove region, different physiographic provinces, lower salinity, dissolved oxygen and sediment biotic structure have a higher influence on the species composition and diversity than other oceanographic conditions.

Bioactivity of seagrass against the dengue fever mosquito Aedes aegypti larvae

Objective:To identify the larvieidal activity of the seagrass extracts.Methods:Seagrass extracts,Syringodium isoelifolium(.S.isoetifolium),Cymodocea serrulata and Hulophila beccarii,were dissolved in DMSO to prepare a graded series of concentration.Batches of 25 early 4th instars larvae of Aedes aegypti(Ae.aegypti) were transferred to 250 ml.enamel bowl containing199 mL of distilled water and 1 mL of plant extracts(0.01 mg- 0.1 mg).After 24 h the mortality rate was identified with the formulae[(%of lest mortality-%of control mortality)/(100-%of control morlality)]× 100.Each experiment was conducted with three replicates and a concurrent control group.A control group consisted of 1 mL of DMSO and 199 mL of distilled water only.Results:The root extract of S.isoelifolium showed maximum larvicidal activity with minimum concentration of extract of LC_(50)= 0.0604 ± 0.0040)μg/mL with lower confidence limit(LCL)-upper confidence limit(UCL) =(0.051-0.071) and LC_(90)=0.0972 μg/mL followed by leaf extract of S.isoelifolium showed LC_(50)=(0.062 ± 0.005)μ'g/mL.The regression equation of pool and leaf extract of S.isoelifolium for4th instar larvae were Y =4.909- 1.32x(R^2= 0.909) and Y= 2.066+ 1.2x(R^2 =0.897) respectively.The results of the preliminary photochemical constituents shows the presence of saponin,steroids,terpenoid,phenols,protein and sugars.Conclusions:from the present study the ethanolic extracts of seagrass of S.isoelifolium possesses lead compound for development of larvieidal activity.

Feasibility of Surfgrass Phyllospadix iwatensis Transplantation Along the Rocky Coasts of Shandong Peninsula,China

Surfgrass Phyllospadix iwatensis is a dominant seagrass species along the east coast of Shandong Peninsula,China.Like other seagrasses in the world,surfgrass has been declining in the past decades.To assess the possibility of transplanting P.iwatensis in the coastal area,a new surfgrass transplant system was designed and applied to conduct a surfgrass transplantation experiment in a tide pool and a subtidal area,and its survival,morphological and physiological parameters were examined from May 2019 to June 2020.The results showed that after a year since transplantation,more than 65%of the transplants survived and the survival rate was higher in the subtidal site than in the tide pool.The morphological measurements including shoot height,leaf width,number of leaves per shoot,rhizome diameter and elongation rate,and number of roots per shoot were all higher in the subtidal area than in the tide pool,showing that the P.iwatensis transplants grew better in the subtidal area than in the tide pool in the study area.These results indicated that surfgrass can be transplanted in the two areas,and it is probably more suitable in subtidal area than in tide pool in the study area.

Temporal and spatial variation of fish community and their nursery in a tropical seagrass meadow

Fish species composition and spatio-temporal variability of the community were studied in a tropical seagrass meadow located in a lagoon in the eastern part of North Sulawesi. The diversity of fish community in the seagrass meadows was relatively high, with the Shannon-Wiener index ranging from 1.57 to 3.69. The family Apogonidae was the most dominant in abundance(8.27 ind./(100 m2)) and biomass(28.49 g/(100 m2)). At the species level,Apogon lateralis and Sphaeramia orbicularis were the most dominant species in abundance and biomass,respectively. For spatial distribution on species, the end, middle and mouth of the lagoon clustered together as a whole, which may be due to the substrate types found in those zones. The fish species, fish abundance and fish biomass were greater in the dry and wet seasons than in the transition season, which is explained by the strong monsoon, which provides a more suitable environment and food for the fish. The maximum length of 93.10% of the captured species was less than their length at maturity, indicating that seagrass meadows are nursery habitats for many fishes. Therefore, protection of the seagrass meadows is essential for fisheries and sustainable resource utilization.

Potential Distribution of Seagrass Meadows Based on the MaxEnt Model in Chinese Coastal Waters

Seagrass meadows are generally diverse in China and have become important ecosystem with essential functions.However,the seagrass distribution across the seawaters of China has not been evaluated,and the magnitude and direction of changes in seagrass meadows remain unclear.This study aimed to provide a nationwide seagrass distribution map and explore the dynamic changes in seagrass population under global climate change.Simulation studies were performed using the modeling software MaxEnt with 58961 occurrence records and 27 marine environmental variables to predict the potential distribution of seagrasses and calculate the area.Seven environmental variables were excluded from the modeling processes based on a correlation analysis to ensure predicted suitability.The predicted area was 790.09 km^(2),which is much larger than the known seagrass distribution in China(87.65 km^(2)).By 2100,the suitable habitat of seagrass will shift northwest and increase to 923.62 km2.Models of the sum of the individual family under-pre-dicted the national distribution of seagrasses and consistently showed a downward trend in the future.Out of all environmental vari-ables,physical parameters(e.g.,depth,land distance,and sea surface temperature)contributed the most in predicting seagrass distri-butions,and nutrients(e.g.,nitrate,phosphate)ranked among the key influential predictors for habitat suitability in our study area.This study is the first effort to fill a gap in understanding the distribution of seagrasses in China.Further studies using modeling and biological/ecological approaches are warranted.

Fish Diversity and Fish Assemblage Structure in Seagrass Meadows at Sikao Bay, Trang Province, Thailand

We investigated the relationship between environmental variables as descriptors of the fish community, in terms of species diversity indices and fish assemblage patterns, in seagrass meadows at Sikao Bay, Trang Province, Thailand. Fish data and water quality parameters were collected from January to December 2012. A total of 10,596 fish specimens of 97 taxa in 48 families from four stations, Kham Bay (7°30'9.21''N, 99°18'7.67''E), Boonkong Bay (7°31'2.49''N, 99°17'40.09''E), Ban Pak Klong (7°36'17.67''N, 99°16'32.89''E) and Sai Cape (7°38'30.19''N, 99°14'49.85''E), were collected using gillnets of three different mesh sizes. The three most diverse families were Leiognathidae, Carangidae and Tetraodontidae, respectively. The dominant species were Atherinomorus duodecimalis, Sillago sihama and Pelates quadrilineatus. Specimens were highly abundant in July and less so in January and species richness was high in July and less so in March. Fish assemblages were classified into two patterns and the average of the Shannon index was 2.7. The environmental parameters in each month were analyzed by one-way ANOVA which did not show significant difference (P > 0.05) of pH, orthophosphate, wind speed and rainfall. Fish diversity and assemblage, and environmental parameters, were categorized into four groups. These could be promoted to local fisheries so that conservation programs cpuld be set up to ensure the ecological sustainability of seagrass meadows.

Quantifying Shoot Density and Biomass of Seagrass Beds in the Central Coast of Vietnam

This study was conducted to provide a comprehensive database of shoot density and biomass characteristics of seagrass beds in several coastal waters in Central Vietnam.The survey process of the characteristics related to shoot density and biomass of seagrass beds was carried out mainly in the dry season(from April to September)during the period from 2017-2019.The data were collected at six sampling locations in Lang Co lagoon,Thua Thien Hue Province;five sampling locations at Cua Dai estuary in Quang Nam Province and Van Phong bay,Khanh Hoa Province;and finally in Ly Son MPA(Marine Protected Area)with nine sampling locations.The characteristics of shoot density collected through the field surveys obtained the difference in the Central Coast region.DW(Dry Weight)biomass of seagrass in Lang Co lagoon and Cua Dai estuary reached 76.56±52.38(g DW)/m2 and 53.21±57.66(g DW/m2),respectively dominated by Thalassia hemprichii and Halodule pinifolia in Lang Co lagoon and Cua Dai Estuary,respectively.The rate of above-and below-ground biomass was different.Seagrass species tended to grow below-ground part compared to above-ground part.The study results would be a significant database on environmental informatics to promote the sustainable management of seagrass resources in the central coastal areas of Vietnam.