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Herbivory is a key ecological process that often determines the composition and abundance of plants. Estimates of herbivory in seagrass meadows are typically lower than those in other vegetated coastal ecosystems, but herbivory can be intense when large herbivorous vertebrates are abundant. We surveyed rates of herbivory on 2 species of tropical seagrasses (Thalassia hemprichii and Enhalus acoroides), the abundance of herbivorous vertebrates, and the diet of 2 abundant herbivorous vertebrates (the green turtle Chelonia mydas and the rabbitfish Siganus lineatus) in lagoons adjacent to remote islands off northwestern Australia. Rates of herbivory in some deployments of tethered seagrass were more than 1000 times higher than rates of production and were among the highest recorded. Consumption exceeded production in half the deployments (9 of 18). Remote underwater video revealed that S. lineatus was the most abundant herbivore. Stomachs of S. lineatus contained mostly seagrass, and models based on stable isotopes indicated that seagrass was the primary source of nutrition. Stomach contents of C. mydas were more variable, containing seagrass and macroalgae (although the sample size was low), but models based on stable isotopes indicated that seagrass was likely the primary source of nutrition. Multiple lines of evidence suggest that the high rates of herbivory on the seagrasses T. hemprichii and E. acoroides are mainly due to direct consumption by the abundant S. lineatus, and perhaps also C. mydas. Seagrass is the primary contributor to the nutrition of both species.

Muh. Aryan R Suci. Growth of Baronang Fish (Siganus canaliculatus) in Basic Net Cages in Different Seagrass Conditions on Lantang Peo Island, Takalar Regency. Lantang Peo Island which is one of the islands which is covered by several types of seagrass. Data collection was carried out from September to October 2016 at the Lantang Peo estuary. The first treatment is observation of density, cover and identification of seagrass. The second treatment is measuring water quality and the last one is measuring the weight and length of the baronang fish. Observation of seagrass species obtained Enhalus accoroides and Thalassia hempichii species. The total density of seagrass at Station I was 47 (teg / m2) 10.03% cover of seagrass, 70 (teg / m2) density of seagrass at Station II was 17.12% and the total density of seagrass at Station III was 90 (teg / m2) 18.13%. Observation of the absolute growth of baronang fish weight at station I of 1 gr. At station II the absolute weight growth of fish is 3 gr and at station III the absolute weight growth of fish is 5 gr. Observations of the absolute length increase of fish at Station I were 1 cm, the absolute length increase of fish at Station II was 2 cm and the absolute length increase of fish at Station III was 3 cm. This difference occurs due to the different density structure of the seagrass at each station.

This research is about studying ecosystems that was designed to analyze the relationship between seagrass ecosystem, environmental competition, and seahorse participation to analyze the distribution of seagrass ecosystems and the abundance of sea horses, and to analyze seahorse-based ecosystem management strategies. This research was conducted in March–June 2017. The determination of the research station was based on purposive sampling technique. Retrieval of seagrass ecosystem data was conducted using a quadrant with the size of 50 x 50 cm transect. Seahorse data were collected using visual census on seagrass transect with a plot of 100 x 100 cm. The relationships between environmental parameters, seagrass ecosystems, and seahorses were calculated using XL Starting 2015. Management of seagrass ecosystems was analyzed using SWOT. Analysis of seagrass included type, density, and INP. Seahorse analysis calculated the abundance of seahorse. The results found 6 species of seagrasses, namely Enhalus acoraides (Ea), Thalassia hemprichii (Th), Halophila ovalis (Ho), Syringodium isoetifolium (Si), Cymodocea serrulata (Cs), and Thalassodendron ciliatum (Tc) with a density that covered sea horse abundance, and INP which had several types of roles in the research location. The management is carried out with the objectives of sustainable resources. Keywords: seagrass ecosystem, seahorse, Sebong Pereh Village

Seagrass has important ecological functions, namely as a nursery-grown, spawning and protection areas for marine biota. In the world, there are 60 species of seagrasses, and in Indonesia, there are 14 species from 7 genera. The waters of North Sulawesi store a high potential of seagrass ecosystems. This study aimed to observe the distribution of seagrass from the Bahoi, Manembo-Nembo, and Tandurusa coast, North Sulawesi, Indonesia. Sampling carried out at the lowest ebb at the lunar or full moon phase. The method used for sampling is random, both for transect and squared lines. The results showed that from the Bahoi, Menembo-Nembo and Tandurusa coast, ten seagrass species from 7 genera and two families were found, namely Enhallus acoroides, Cymodocea rotundata, Cymodocea serrulata, Halodule uninervis, Halodule pinifolia, Halophila minor, Halophla ovalis, Syringodium isoetifolium, Thalassia hemprichii, dan Thalassodendron ciliatum. Information on seagrass distribution in an area can be taken into consideration for the government and related agencies in drafting a regulation in the management of seagrass ecosystem resources.

Lamun merupakan tumbuhan laut yang memiliki peran yang tidak kalah penting dengan ekosistem pesisir lainnya seperti terumbu karang dan mangrove baik dari segi fisik, ekologi, dan ekonomi. Indonesia memiliki 12 jenis lamun dari 58 jenis lamun di dunia. Tidak semua wilayah di Indonesia memiliki jumlah jenis yang sama karena perbedaan kondisi lingkungan atau tekanan antropogenik, sehingga perlu ada kajian keragaman jenis lamun di wilayah perairan Indonesia. Penelitian ini bertujuan untuk mengidentifikasi struktur komunitas lamun dan keterkaitan antara kerapatan lamun dan parameter lingkungan di perairan Pulau Wanci, Sulawesi Tenggara. Stasiun pengamatan berada pada daerah padang lamun yang dibagi menjadi 4 stasiun. Metode sampling yang digunakan mengacu pada McKenzie et al. (2001) menggunakan transek kuadrat 50 cm x 50 cm. Selanjutnya menghitung jumlah tegakan lamun dan mencatat jenis lamun yang ditemukan pada tiap transek kuadrat. Hasil penelitian menunjukkan bahwa ditemukan 7 jenis lamun di perairan Pulau Wanci yaitu Halophila ovalis, Halodule uninervis, Cymodocea rotundata, Thalassia hemprichii, Enhalus acroides, Thalasodendron ciliatum, dan Syringodium isoetifolium dengan kerapatan tertinggi didominasi oleh T. hemprichii, H. uninervis, dan C. rotundata dengan pola sebaran keseluruhan adalah mengelompok. Terdapat keterkaitan antara kerapatan lamun dengan parameter lingkungan, substrat berpasir memiliki korelasi positif yang tinggi terhadap kerapatan lamun sedangkan substrat liat, kecepatan arus, salinitas, dan suhu memiliki korelasi negatif yang rendah sampai tinggi terhadap kerapatan lamun di perairan Pulau Wanci.

Visual census surveys utilizing a distance sampling approach were undertaken in Saipan Lagoon to determine the density of humphead wrasse (HHW) in four shallow water habitats, and compared to observations in the Saipan nighttime commercial spear fishery. Fish observed from the survey ranged in total length from 6.5 to 35 cm total length, generally smaller than the range of fish sampled from the commercial fishery of 16 to 47 cm total length. The majority of survey observations occurred in the central and northern part of Saipan Lagoon, which correlated with capture locations documented in the commercial fishery landings. Analysis of contemporary and historical commercial fishery data showed that HHW could not be considered primary fishery target species. Distance sampling results indicated that coral/hard bottom and Enhalus acroroides seagrass were the habitats most important to HHW, as reflected by higher density estimates. The use of distance sampling was useful in estimating the spatial distribution and density of HHW, and should be considered when assessing other rare marine finfish species.

Dugongs, exclusively seagrass foragers, are globally threatened marine mammals. Knowledge on their feeding biology has been derived from few direct observations and mostly by analysis of stomach contents. Given limitations in data from Indian populations, dugong strandings serve as an opportunity to understand their dietary composition through gut sampling. In this paper, we utilize the gut contents collected from stranded dugongs to detect differences in the seagrass foraging between two isolated pockets of dugong distribution (Tamil Nadu and Gujarat) and supplement existing knowledge on dugong feeding biology in Indian waters. We extracted, enumerated and identified seagrass species from dugong gut contents. The proportion of seagrass leaf fragments were found higher (>40%) than other fragments in all the gut samples analysed. We recorded two seagrass genera (Halophila spp. and Halodule spp.) from Gujarat and five seagrass genera (Halophila spp., Halodule spp., Cymodocea spp., Enhalus spp., Syringodium spp.) from Tamil Nadu dugong individuals. We also obtained anthropogenic debris such as plastic, fishing net and wood fragments from the gut samples. We suggest enhanced monitoring of seagrass habitats and fine spatial scale threat mapping in entire dugong distribution range in India.

Human-induced land use in coastal areas is one of the main threats for seagrass meadows globally causing eutrophication and sedimentation. These environmental stressors induce sudden ecosystem shifts toward new alternative stable states defined by lower seagrass richness and abundance. Enhalus acoroides, a large-sized tropical seagrass species, appears to be more resistant toward environmental change compared to coexisting seagrass species. We hypothesize that reproductive strategy and the extent of seedling recruitment of E. acoroides are altered under disturbance and contribute to the persistence and resilience of E. acoroides meadows. In this research, we studied eight populations of E. acoroides in four lagoons along the South Central Coast of Vietnam using 11 polymorphic microsatellite loci. We classified land use in 6 classes based on Sentinel-2 L2A images and determined the effect of human-induced land use at different spatial scales on clonal richness and structure, fine-scale genetic structure and genetic diversity. No evidence of population size reductions due to disturbance was found, however, lagoons were strongly differentiated and may act as barriers to gene flow. The proportion and size of clones were significantly higher in populations of surrounding catchments with larger areas of agriculture, urbanization and aquaculture. We postulate that large resistant genets contribute to the resilience of E. acoroides meadows under high levels of disturbance. Although the importance of clonal growth increases with disturbance, sexual reproduction and the subsequent recruitment of seedlings remains an essential strategy for the persistence of populations of E. acoroides and should be prioritized in conservation measures to ensure broad-scale and long-term resilience toward future environmental change.

Background: Seagrass is a group of closed seed plants (Angiosperms) and single-sided (monocotyledonous) plants which are able to live permanently below sea level. One of the most abundant types of seagrass in Indonesian waters is seagrass Enhalus acroides. The specialty of seagrasses Enhalus acoroides is that the seeds can be used as food ingredients in several regions. Some people in Maluku process seagrass seeds into vegetables for daily use. In addition, seagrass seeds Enhalus acoroides which have good nutrition can be processed into milk products that can be an alternative to animal milk. Methods: The viscosity test for seagrass seed milk using the Ostwald method and microbiological analysis through the plate count total test using the SNI 2008 guidelines. This research was located in the Basic Biology Laboratory, Faculty Teacher Training and Education, Pattimura University and the Industrial Research and Standardization Center Laboratory in Ambon. Results: Viscosity values ​​in seagrass seed milk in the treatment group S0 (without sugar) 121.69 cP, treatment S1 (100 grams of sugar) 160.76 cP and treatment of S2 (200 grams of sugar) 156.38 cP while the results of the Total Plate Count test in seagrass seed milk with treatment S0 (no sugar) 7.1x101, treatment S1 (100 grams of sugar) 6.0x101 and treatment S2 (200 grams of sugar) 7.0x101. Conclusion: The highest viscosity value is in the treatment of S1 (100 grams of sugar) 160.76 cP and the lowest viscosity value is in the treatment of S0 (without sugar) 121.69 cP while the highest microbial colonies are in treatment S0 (without sugar) 7,1x101 and the lowest microbial colonies were in treatment S1 (100 grams of sugar) 6.0x101.

Microplastics is an emerging environmental problem in the world. However, presence and fate of microplastics in seagrass meadows are barely known. In this study, the abundance and diversity of microplastic from Enhalus acodoides vegetated sites and bare sites were quantified and characterized in Xincun bay and Li’an bay, Hainan, China. Microplastics ranged from 80.0 to 884.5 particles per kg of dry sediment, and fibers were the dominant shape. The most frequent colors of microplastics were blue, transparent and black. The dominant size of microplastics was in the range of 125–250 μm. And the seagrass sediments were enriched in microplastics 2.1 and 2.9 times for Xincun bay and Li’an bay, respectively. The trap effect of seagrass was non-selective regarding the shape, color and size of microplastics. High anthropogenic pollution and poor beach management may contribute to higher concentrations of microplastics in Li’an bay.

Random forest is a machine learning algorithm that can be used to improve the classification accuracy of mapping using remote sensing, especially for seagrass mapping in a complex optically water shallow. This research is aimed to map seagrass species composition and percent cover using random forest classification and regression using PlanetScope image. Optically shallow water around Labuan Bajo was selected as the study area. Sunglint and water column corrections were applied to the surface reflectance image. Principle Component Analysis (PCA) transformation was applied on surface reflectance bands, deDeglint bands, and depth-invariant index bands. These bands were used as the input band for random forest classification and regression algorithm, using field data to train the algorithm. Benthic field data was collected by the photo transect and seagrass field data was collected by the photo quadrat transect technique. Benthic habitat classification scheme was constructed based on the variation of benthic habitat insitu, which consisted of coral reefs, seagrass, macroalgae, and bare substratum. Seagrass species composition classification scheme was constructed following the variation of seagrass species insitu, which consisted Enhalus acaroides (Ea), Enhalus acaroides mixed Syringodium isoetilolium (EaSi), Enhalus acaroides mixed Thalassia hemprichii (EaTh), Halodule uninervis (Hu), Mixed species class, Thalassodendron ciliatum (Tc), Thalassodendron ciliatum mixed Enhalus acaroides (TcEa), Thalassia hemprichii (Th), Thalassia hemprichii mixed Cymodocea rotundata (ThCr), and Thalassia hemprichii mixed Syringodium isoetilolium (ThSi) class. Accuracy assessment using independent field data showed that random forest algorithm produced 63.57%- 72.09% overall accuracy for benthic habitat and 83.52%-85.71% overall accuracy for seagrass species composition. Random forest regression for seagrass percent cover produced R 2 between 0.78-0.81 with the error of prediction between 14.59-15.26.

Seagrass hydrodynamic regimes are important to understand and also to guide seagrass restoration, which is of great interest in Indonesia because of environmental threats to the exceptionally high seagrass species richness. Hydrodynamic regimes influence the physical stability of seagrass beds, sedimentation rates, and the advection of nutrients and food to seagrasses and associated organisms. In a flume, we determined the effect of canopies of Cymodocea rotundata, Enhalus acoroides, Halodule uninervis, Syringodium isoetifolium and Thalassia hemprichii on water velocity, turbulence, turbulence intensity and shear velocity. The taller canopies of Enhalus and Cymodocea slowed water flow, but the shorter canopies (Enhalus is a good candidate for transplantation in terms of reducing mean water flow and shear velocities, but that Halodule should also be considered as it also reduced shear velocities and it spreads quickly after transplantation. Our results extend the understanding of seagrass-hydrodynamic relationships to include very short canopies, unlike the taller canopies studied to date.

Ambo-Rappe R, La Nafie YA, Syafiuddin, Limbong SR, Asriani N, Handayani NT, Lisdayanti E. 2019. Short Communication: Restoration of seagrass Enhalus acoroides using a combination of generative and vegetative techniques. Biodiversitas 20: 3358-3363. Seagrass areas have been declining in extent worldwide, with associated loss in seagrass ecosystem functions and services. Seagrass restoration is important to mitigate, halt and reverse such declines and their consequences. Generative propagation has benefits in terms of genetic biodiversity, however, survival of seagrass seedlings has often been poor especially in high energy environments. Terrestrial restoration often uses shade trees to protect vulnerable seedlings. This study aimed to evaluate the feasibility of a similar approach in the marine environment, using adult plants to protect seedlings of the tropical seagrass Enhalus acoroides (L.f.) Royle. Enhalus seeds taken from a donor bed were germinated and grown into seedlings, then planted in a location with high hydrodynamic exposure at three different densities (high, medium, and low). Adult Enhalus transplants were co-planted to provide three levels of protection: fifty (high), ten (medium), and none (no protection). Results showed that high-density seedling co-planting with high protection from adult transplants had significantly (p< 0.05) higher six-month survival rate compared to the other treatments. Our results indicate that, even in high energy environments, co-planting seedlings with adult transplants may combine the advantages of generative and vegetative propagation methods, promoting greater short-term effectiveness in terms of seedlings survival and growth in the restored seagrass meadows.

In the Philippines, the practice of planting mangroves over seagrass has been a practice done to promote coastline protection from damages done by storms. Despite the added protection to the coastline, the addition of an artificial ecosystem gradually inflicts damage to the ecosystem already established. In this study, seagrass communities that had no history of mangrove planting were compared with those that had mangrove planting. The percent substrate cover of seagrass in the sampling areas was determined, and the macroinvertebrates present in the sampling areas were also observed. The study was conducted based on reports of mangrove planting activity that disrupted seagrass functions on Santa Fe, Bantayan Island, Cebu. Transect-quadrat method sampling was done to assess the chosen sites. Six species of seagrass was found on the site without mangrove planting which was barangay Ocoy (Cymodocea sp., Thalassia sp., Halodule sp., Enhalus sp., Halophila sp., and Syringodium sp.) and had a higher percent cover, while only four were found on the site with mangrove planting (barangay Marikaban). It was also found that barangay Marikaban had a lesser Shannon-Wiener and Simpson’s index compared to barangay Ocoy. Jaccard’s index of similarity between the two sites was low. With the results of the assessment, we recommend proper monitoring of future mangrove planting activities and that these activities should not disrupt another ecosystem as all ecosystems are important.

Coastal areas are at increasing risk from flooding and erosion due to coastal development and climate change. Seagrass meadows, like other coastal ecosystems, can stabilise sediments, indirectly reducing coastal erosion. There is evidence that seagrass can reduce both the erosion of seabeds and lateral erosion of seagrass cliffs. However, these previous studies have only considered seagrass species whose below-ground biomass form dense root mats. This study aimed to investigate whether Enhalus acoroides, a species which does not form root mats, reduces lateral erosion rates of seagrass cliffs. To do this, samples of E. acoroides collected in sandy sediments within Xincun Bay China were transplanted into a wave flume. Lateral erosion rates were measured under exposure to waves for five cliff heights over 1 h. There was an interaction between cliff height and time on the rate of erosion, with higher erosion rates earlier in the experiment for larger cliff heights. The cores with the E. acoroides persisted longer than unvegetated cores, regardless of cliff height, but this result was not assessed statistically due to constraints in the analyses. The below-ground biomass of E. acoroides samples in this study was higher than values previously reported in the literature. Overall, these results suggest that non-dense root-mat forming seagrass species may not provide equivalent sediment stabilisation as dense root-mat-forming species, likely due to the reduced binding structure of the roots in species such as Enhalus.

Taxonomic challenges of seagrasses were met by using 18S ribosomal subunit of ribosomal deoxyribonucleic acid (18S rDNA) sequence data of 14 seagrass species from India and two temperate species from Germany. The phylogenetic trees presented are based on the 18S rDNA sequence analysis of 41 nucleotide sequences including sequences obtained in the present study as well as previously published sequences of freshwater and saltmarsh plants, and seagrasses for identifying the evolutionary lineage. The 18S rDNA data indicates independent origin of temperate and tropical seagrasses with the genus Halophila as the intermediate group for both the regions. Based on the complex morphological structures the Halophila group represents the basal form among seagrasses whereas Enhalus is considered to be the most recently originated seagrass species. In that context, the marine Hydrocharitaceae group of Enhalus, Thalassia and Halophila has been proposed to be separated into two groups such as Enhalus/Thalassia and Halophila subfamilies. Hence, the present systematic studies warrant a revised taxonomy for seagrasses, which better reflects the phylogenetic results obtained from molecular and conventional data.

Seagrass is one of the marine resources that considerably potential as a CO2 absorbent and functioned as carbon sinks in the oceans known as blue carbon. The result of carbon sequestration from the process of photosynthesis is stored as carbon stocks on seagrass tissue, or streamed to multiple compartments, such as sediment, herbivores and other ecosystems. This study aims to assess the potential for carbon stock storage in biomass on a tissue of seagrass in Sanur Beach coastal area. The observations of seagrass are included the seagrass type, seagrass stands, and measurement of environmental parameters. Then the sampling was conducted to obtain the value of seagrass biomass. The carbon stocks obtained through the conversion of biomass by using carbon concentration analysis of seagrass tissue and then carried a spatial distribution of carbon stocks. Types of seagrass found in Sanur Beach coastal area consist of eight species that are Enhalus acroides, Thalassia hemprichii, Halophila ovalis, Syringodium isoetifolium, Cymodocea serrulata, Cymodocea rotundata, Halodule uninervis and Halodule pinifolia. The result of the carbon stock seagrass in the bottom substrate is 60% greater than the carbon stock in the top substrate which is 40%. Seagrass covering 322 ha of Sanur Beach coastal area with a total potential carbon storage of 66.60 tons or 0.21 tons / ha. Seagrass key role as a carbon storage is on the bottom substrate tissue, and Enhalus acroides is a seagrass species that contributes the most to the carbon storage.

Seagrass might impact metal bioavailability in sediments with physiological processes that occur at the root and rhizome. Seagrass growth may increase bioavailability due to oxygen transport from leaves to the root systems. This study aims to analyze the concentrations of bioavailable Pb and Cu in sediments with and without seagrass. This study was done at two sites in Spermonde Islands, South Sulawesi, Indonesia. All metals analysis and sediment parameters were conducted on dry

Coastal utilization that is not directed by the surrounding community such as sand and stone extraction and disposal of solid and liquid waste to the beach can cause damage to coastal ecosystems including seagrass ecosystems. Efforts to restore the diminishing condition of the seagrass ecosystem is through seagrass transplantation activities using the TERFS (Transplanting Eelgrass Remotely With Frame System) method. This research was conducted from February 2019 - 31 May 2019. This study aimed to analyze the survival rate and growth rate and physical chemical factors of the waters that affect the growth of the seagrass Enhalus acorides transplanted using the poly bag method and the TERFS method (Transplanting Eelgrass Remotely With Frame System) in the coastal waters of Waai Village, Central Maluku Regency. The results showed that the Enhalus acorides seagrass had a survival rate of 100%. The value of the growth of seagrass for three weeks of observation is in frame 1 of 0.43 cm / day, in frame II of 0.47 cm / day and in frame III of 0.46 cm / day. The average value of the physical chemistry parameters of the waters at the transplantation location using the coastal waters of Waai Village, Central Maluku Regency is still within the range of environmental parameters of the marine waters supporting the growth of seagrass Enhalus acorides, including temperatures of 30.67 ℃, brightness of 100%, water depth of 45.67 cm, current velocity of 0.46 cm / sec, salinity of 29 ‰ and water pH of 7.53. The average value of nitrate content in the water column

Research of seagrass vegetation structure has been carried out in Waemulang Coastal Waters, South of Buru Regency. This explorative study uses a linear quadrate transect method with 13 transect lines that are mounted perpendicular to the coastline, starting from the highest tide to the lowest tide. The results showed mixed vegetation types with species composition consisting of 5 seagrass species, namely: Enhalus ocoroides, Halophila ovalis, Thalassia hemprichii, Cymodocea serrulata and Cymodocea rotundata, which are members of 2 orders, 2 families, and 4 genera of seagrasses. The species that are most commonly found and have a value of density, relative density, frequency type, relative frequency, percentage of cover, relative closure, and index of important value which is higher, namely Enhalus acoroides, while the lowest, namely Halophila ovalis. In addition, the diversity index of seagrass species is 1,493, or belongs to medium category and the dominance index of seagrass species is 0.239, or there is no dominance of species. It can be concluded that the seagrass vegetation structure in Waemulang Coastal Waters is still relatively stable and Enhalus acoroides is the most influential seagrass species in the growing community. Environmental parameters are very supportive for seagrass growth in this area.

Seagrasses have evolved independently at least four times throughout their evolutionary history. All seagrasses are members of the monocot order Alismatales. A new molecular phylogenetic analysis, applying a molecular clock based on recently redefined fossil evidence, provides a framework for describing the timing and relationships of seagrass lineage evolution. The deeper time phylogenetic history of the marine monocotyledons dates back approximately 105 million years ago (Ma) to an ancestor from which two significant lineages evolved more recently. The marine Hydrocharitaceae (Enhalus, Thalassia and Halophila) are a tropical globally distributed lineage which include Australian endemic species of Halophila. The Cymodoceaceae lineage and the Zosteraceae/Potamogetonaceae diverged some ~67 Ma but in each lineage the genera arose more recently. Most seagrass species appear to have evolved in the last ~5 Ma, some more recently. The extant distribution of species will not be the result of vicariance but of long distance connectivity at a global scale. The most significant implication of these results to global biogeography is that there must have been, and likely continues to be, ongoing long distance dispersal leading to the current widespread distributions of species and congeners. The Australian seagrass flora represents all the major evolutionary lineages of seagrasses except the northern hemisphere Phyllospadix, a major clade of Zostera and some of the forms of Halophila. Pollination efficiency is a significant potential driver in the evolution of filiform pollen, and is likely associated with the single seeded fruit in water pollinated species of seagrass in the lineages of seagrass that exhibit this character.

Using nursery stock grown from seeds rather than transplants could improve success of seagrass restoration. In Indonesia, Enhalus acoroides is the climax seagrass species and the target species for restoration. However, optimal conditions for seed storage are not known. The aim of this study was to determine optimal storage conditions for E. acoroides seeds to maximize germination and growth. Seed germination was examined under different lengths of storage and storage temperatures (room and refrigerator) for Enhalus fruits (with the seed inside). Enhalus seeds did not survive well and turned black after 2 days in the refrigerator (4 °C). Seeds held in room temperature (∼30 °C) for 2–11 days survived and grew to seedlings. Survival of the seedlings in the field was also correlated with the performance of the seedling when raised for 10 weeks in the laboratory. Seedlings stored in refrigerator had reduced survival (87.5%) in the field compared to seedlings stored 2–5 days in room temperature (100% survival). However, seeds stored up to 8 days, even at room temperature, produced seedlings that did not survive well either in the laboratory or in the field (survival was less than 20%). Our results indicate that long-term seed storage in the laboratory will not be feasible for restoration. Because using seeds for restoration is important for maintaining genetic diversity, the establishment of a seedling nursery in the field provides a viable alternative for Enhalus restoration, although it will be logistically more challenging than a seed storage bank.

Seagrass meadows are a crucial component of tropical marine reef ecosystems. Seagrass plants are colonized by a multitude of epiphytic organisms that contribute to broadening the ecological role of seagrasses. To better understand how environmental changes like ocean acidification might affect epiphytic assemblages, the microbial community composition of the epiphytic biofilm of Enhalus acroides was investigated at a natural CO2 vent in Papua New Guinea using molecular fingerprinting and next-generation sequencing of 16S and 18S rRNA genes. Both bacterial and eukaryotic epiphytes formed distinct communities at the CO2 -impacted site compared with the control site. This site-related CO2 effect was also visible in the succession pattern of microbial epiphytes. We further found an increased relative sequence abundance of bacterial types associated with coral diseases at the CO2 -impacted site (Fusobacteria, Thalassomonas), whereas eukaryotes such as certain crustose coralline algae commonly related to healthy reefs were less diverse. These trends in the epiphytic community of E. acroides suggest a potential role of seagrasses as vectors of coral pathogens and may support previous predictions of a decrease in reef health and prevalence of diseases under future ocean acidification scenarios.

Here, we report the draft genome sequence of Marinobacter hydrocarbonoclasticus strain STW2, which was isolated from the rhizosphere of seagrass Enhalus acodoides . This study will facilitate future studies on the genetic pathways of marine microbes capable of both polycyclic aromatic hydrocarbon degradation and nitrate reduction.

Seagrass beds are flowering plants that live on the seabed. Seagrass provides a habitat for diverse flora and fauna, spawning ground, nursery ground, raising ground, and feeding ground. Balanan Resort – Baluran National Park has many beaches, such as Kajang Beach, Si Banjir Beach, Kakapa Beach, and Serondo Beach. This study was aimed to determine species composition, seagrass dominated, and the diversity index of seagrass and substrate in Resort Balanan - Baluran National Park. This research was carried out in Kajang Beach, Sibanjir Beach, Kakapa Beach, and Sirondo Beach from August to September 2015 using belt transect method, each transect consists of 15 plots (19 transects = 285 plots) and using the frame of 1x1 m. This research found seven genera and ten species : Cymodoce (C rotundata and C. serrulata), Syringodium (S. isoelifolium), Thallassodendron (T. ciliatum), Enhalus (E. acoroides) , Halodule (H. univernis and H. pinifolia), Halophila (H. ovalis and H. decipiens), and Thalassia (T. hemprichii)....

Although the influence of seagrasses on the diversity and abundance of associated fauna is generally well understood, the effects of seagrass specific identity are not. To determine whether benthic epifaunal and infaunal assemblage patterns vary by the identity of dominant seagrass species in shallow water meadows, we compared quantitative measures of faunal species richness, abundance, and assemblage structure among beds dominated by Cymodocea rotundata, Enhalus acoroides, and Thalassia hemprichii; the study site was at Lopez Jaena, Misamis Occidental Province in the southern Philippines. The Cymodocea-dominated vegetation had higher seagrass shoot density and lower seagrass biomass than those dominated by Enhalus and Thalassia. Across vegetation types, we encountered 30 and 15 species of epifauna and infauna at average densities of 1.73 and 0.82 animals/core (0.0314 m2), respectively. Neither densities and species richnesses of epifauna and infauna nor species composition varied significantly by vegetation type. Multivariate analyses of macrofaunal assemblage structure and abiotic/biotic environmental factors demonstrated that seagrass aboveground biomass explained a significant proportion of the multivariate variation in epifaunal species composition (39%); none of the potential explanatory variables was related to variation in ecological parameters of the infauna. Thus, seagrass specific identity is not a good predictor of either macrofaunal abundance or diversity patterns. Although the ecological parameters of the benthic macrofauna may be influenced by seagrass biomass and structure, responses differ between epifauna and infauna.

This study is a part of transplanting Enhalus acoroides carried out from November 2006 to February 2007 as a compensation of 1.6 ha loss of seagrass beds at Bojonegara, which was facilitated by NGO Rekonvasi Bhumi and funded by oil drilling company, PT Apexindo. The transplanting site was located at Terate, Banten Bay which has muddy substrate with high water dynamic. Healthy transplant seedlings were collected from monospecific vegetation with muddy substrate of donor site at Kepuh. The seedlings of Enhalus have different length of rhizome, 5 and 10 cm, with leaf length of 60 cm and removed roots. Transplanting of Enhalus acoroides was conducted using single shoot seedlings with 9 seedlings per unit in 1 meter square with 5 replicates. Light coefficient (1.17-5.06) and percentage of silt and clay (86.45 ± 2.18 %) at transplant site Terate were both higher than the donor site Kepuh with light coefficient values of 1.21-2.46 and percentage of silt and clay 64.00 ± 5.57 %, respectively. Seedling growth survival of Enhalus acoroides in February 2007 with rhizome length of 10 cm was higher (51.11 ± 25.58%) than seedlings with rhizome length of 5 cm (17.78 ± 18.59%). Leaf length and wide Enhalus acoroides transplants decreased during the study. Water dynamic (waves) influenced light coefficient and turbidity at the transplant site. Field observations showed that mortality of Enhalus acoroides transplants was caused by mud smoothering the leaves and barnacle growing on them. They made the leaves lost their buoyancy, laid on the surface, rotten and finally died. Wave is one of the important physical factor affecting the transplanting seagrass on the muddy substrate.

Seagrass is a high level and a flowering plant that is fully adapted to life in the coastal and has ability to store carbon by 10% of the carbon content in the oceans. The research doing at Gunung Botak Bay Coastal South Manokwari Regency with objective of research to estimate seagrass density and to estimate rate accumulation of carbon from Enhalus acroides. Some the stages of the research done is density sample as long to period 2015 (April and Mei) into (September and Ocktober). Other sampling to collecting seagrass to estimate carbon storage in part like daun, rhizome root and substrat. Result to showing average carbon accumulation of seagrass in above below ground is rhizome part and higher in Statiun1 (13.16±3.8),stasiun 3 (5.4±2.9) dan stasiun 5 (6.2±1.1) or the generally accumulation carbon in the three is 8.24 kg from Enhalus acroides. Future more, accumulation carbon in sediment as a 1664,2 in dept 0-20 cm and 20-60 cm. Seagrass carbon storage capabilities will assist in mitigation efforts to reduce the impact of climate change in Indonesia, especially in West Papua.

The seagrass Posidonia oceanica is considered one of the oldest and largest living organisms on Earth. Notwithstanding, given the difficulty of monitoring its fruits and seeds in the field, the development of P. oceanica during its sexual recruitment is not completely understood. We studied the stages of development of P. oceanica seeds from their dispersion in the fruit interior to their settlement in sediment through histological, ultrastructural and mesocosm experiments. P. oceanica sexual recruitment can be divided into three main stages that focus on maximising photosynthesis and anchoring the seedlings to the sediment. In the first stage (fruit dispersion), seeds perform photosynthesis while being transported inside the fruit along the sea surface. In the second stage (seed adhesion), seeds develop adhesive microscopic hairs that cover the primary and secondary roots and favour seed adhesion to the substrate. In the last stage (seedling anchorage), roots attach the seedlings to the substrate by orienting them towards the direction of light to maximise photosynthesis. The adaptations observed in P. oceanica are similar to those in other seagrasses with non-dormant seeds and fruits with membranous pericarps, such as Thalassia sp. and Enhalus sp. These common strategies suggest a convergent evolution in such seagrasses in terms of sexual recruitment. Understanding the sexual recruitment of habitat-forming species such as seagrasses is necessary to adequately manage the ecosystems that they inhabit.

Middle Eocene seagrass compressions occur in the Avon Park Limestone Formation near Gulf Hammock on Florida's west coast. One group of specimens resembles two seagrass species of the hydrocharitaceans, Thalassia and Enhalus, that are living today in tropical and subtropical shallow marine environments. The Eocene plant has a dimorphic rhizome system consisting of a creeping, monopodial, plagiotropic rhizome with small roots and orthotropic laterals (short shoots) that occur in pairs every three to five nodes. Laterals bifurcate and produce glabrous eligulate leaves in an alternate and distichous arrangement. Foliage leaves have fibrous basal sheaths, blades with parallel venation, perpendicular and oblique cross veins, prominent midrib, and smooth, entire margins. Throughout the plant are numerous brown-coloured tanniferous dots and deposits of small calcium oxalate crystals. Based on features of these non-reproductive structures, the Florida Eocene seagrass is recognized as a new genus and species Thalassites parkavonensis in the Hydrocharitaceae. © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society, 2008, 157, 19–30.

The Saipan Lagoon (Northern Mariana Islands) was first examined for benthic compo- sition and habitat distribution in the late 1940s. Here, we employ a 4-stage approach to evaluate and explain change in the distribution of the 9 habitats previously demarcated. We show that there have been considerable reductions in seagrass, staghorn Acropora, and Acropora palifera dominated habi- tats (-3.72, -1.26, and -1.37 km 2 , respectively) that were replaced by 6.16 km 2 of sand (~20% of the lagoon area). Multiple regressions showed that the spatial extent of Enhalus seagrass was positively related with, and best predicted by, the adjacent watershed area and lagoon width. Although the interaction was not as strong, Enhalus also increased in accordance with human development. The size of the Halodule seagrass and macroalgal habitat was negatively related to water-flow velocities and positively related to human development, while its integrity (i.e. the density of seagrass within a given habitat) decreased with human development. Taken together, the results suggest Enhalus and Halodule respond differently to proxies of watershed pollution, and contradict contemporary doctrine linking pollution with reduced seagrass density. This study found no relationship between offshore habitats and watershed characteristics, but suggests their expansion and contraction on relatively short time scales is a result of large-scale disturbances such as typhoons. We posit that, while habitat integrity can be altered by human disturbances, habitat identity is only altered under extreme condi- tions. In summary, this study advances habitat mapping by increasing resolution and accuracy, which, in turn, improves the texture at which reef ecology is used by management.

Dried Ulva reticulata has been proven as a feeding stimulant for the collector sea urchins (Tripneustes gratilla). The purposes of this study were to determine the optimal dose of dried U. reticulata as a feeding stimulant into artificial feed and its effect on the gonad condition of the collector sea urchins, T. gratilla. Previously, starved sea urchins (ca. 66 mm diameter, n=7) was held in 80-l aquarium volume with flow through seawater system (6.25 l/hour inlet and outlet). Sea urchins were fed with diet containing 0, 10, 20, or 30% of dried U. reticulata (designated control, U-10, U-20, and U-30 respectively) ad libitum for 38 days. Each treatment was given 3 replicates. Survival rate, feed consumption, and gonad conditions (gonad index, biochemical composition of the gonad, gonad histology, and egg diameter) parameters were quantified and compared to sea urchins fed with the mixture of fresh macroalgae (Gracilaria lichenoides and Padina) and seagrass (Enhalus acoroides). The results showed that the addition of dried U. reticulata into artificial feed by 10% from feed weight (U-10) was the optimal dose recommended. Sea urchins treated U - 10 diet resulted in gonad index and egg diameter (5.02 % and 82.66 µm each), were higher than other diet treatments. However, this diet treatment was not able to homogenize the reproductive phase composition of T. gratilla. Keywords: Ulva reticulata, Feeding Stimulant, Tripneustes gratilla, Gonad Condition

Enhalus acoroides is the largest population of seagrasses in Indonesia. However, growth rate and productivity analyses of Enhalus acoroides and the use of satellite data to estimate its the productivity are still rare. The goal of the research was to analyze the growth rate, productivity rate,seasonal productivity of Enhalus acoroides in Pari island and its surroundings. The study was divided into two phases i.e., in situ measurments and satellite image processing. The field study was conducted to obtain the coverage percentage, density, growth rate, and productivity rate, while the satellite image processing was used to estimate the extent of seagrass. The study was conducted in August 2011 toJuly 2012 to accommodate all four seasons. Results showed that the highest growth rate andproductivity occurred during the transitional season from west Monsoon to the east Monsoon of 5.6cm/day and 15.75 mgC/day, respectively. While, the lowest growth rate and productivity occurred during the transition from east Monsoon to the west Monsoon of 3.93 cm/day and 11.4 mgC/day, respectively. Enhalus acoroides productivity reached its maximum during the west Monsoon at 1081.71 mgC/day/m2 and minimum during east Monsoon with 774.85 mgC/day/m2 . Based on ALOS data in 2008 and 2009, total production of Enhalus acoroides in the proximity of Pari islands reached its maximum occur during the west Monsoon (48.73 – 49.59 Ton C) and minimum during transitional season (16.4-16.69 Ton C). Potential atmospheric CO2 absorption by Enhalus acoroides in Pari island was estimated at the number 60.14 – 181.82 Ton C.

Banten Bay in Indonesia is a coastal area which has been highly affected by human activity. Previous studies have reported the presence of lead (Pb) and copper (Cu) heavy metals in the seawater of this area. This study was conducted to measure the accumulation of Pb and Cu in seawater, sediment, leaf tissue, and root tissue of the seagrass species Enhalus sp. Sampling was conducted at two observation stations in Banten Bay: Station 1 (St.1) was located closer to the coastline and to industrial plants as source of pollution, while Station 2 (St.2) was located farther away offshore. At each station, three sampling points were established by random sampling. Field sampling was conducted at two different dates, i.e., on 29 May 2012 and 30 June 2012. Samples were processed by wet ashing using concentrated HNO3 acid and measured using Atomic Absorption Spectrometry (AAS). Accumulation of Pb was only detected in sediment samples in St.1, while Cu was detected in all samples. Average concentrations of Cu in May w...

Fine mesh enclosures (0.9 m 2 in basal area, 1 m high, with 100 μm mesh) and a jet-net retrieval system were developed to test the influence of juvenile prawn stocking density on growth rates in (1) different months (April and October/November) and (2) different types of intertidal seagrass beds in the Embley River estuary of tropical Australia. Small juvenile tiger prawns (3-6 mm in carapace length, CL) were stocked in enclosures at densities of 4-32 prawns per enclosure (4.4-35.5 prawns m -2) on a high biomass seagrass bed (about 70 g m -2 of mostly Enhalus acoroides) and one with low biomass (about 10 g m -2 of mostly Halodule uninervis). After 2-3 weeks in the enclosures, recovery rates, and hence possibly survival, were greater on the high biomass Enhalus than on the low biomass Halodule. However, not all fish and crustaceans could be excluded from the enclosures. Growth rates were twice as fast on the high biomass Enhalus than on the low biomass Halodule. It is likely that the high biomass Enhalus, with its greater surface area, supported more epiphytic flora and fauna and reduced the potential for interference competition between prawns, compared with the low biomass Halodule. Growth rates on Enhalus were significantly faster at a stocking density of 4 prawns per enclosure (1.3 mm CL week -1) than at a stocking density of 16 and 32 prawns per enclosure (both 0.8 mm CL week -1), and did not differ significantly between April and October/November (temperatures were about 30°C at both times). The mean growth rate at 8 prawns per enclosure (1.1 mm CL week -1) did not differ significantly from those at 4, 16 and 32 prawns per enclosure. These results from two seagrass beds suggest that the carrying capacity for juvenile tiger prawns was greater in the high biomass Enhalus than the low biomass Halodule bed.

Studies on the diversity and density of macroalga have been carried out in Ambalau island waters, south Buru district since 2010. The purposes of this study were to determine the diversity, density, frequency, and the dominance of macroalga in the coastal waters of the Ambalau island. Data collection with squares transect line method were conducted in October-November 2009. The results showed that the coastal areas of Masawoy showed the highest values in diversity, density, frequency, and the dominance of macroalga in the study area with 33 species from 20 genera consisting of 14 species of green alga, 10 species of red alga, and 9 species of brown alga. Caulerpa, Halimeda, Gracilaria, Acanthophora, Sargassum, and Padina were the most dominance in the region. The highest diversity, density, frequency, and dominance of macroalga on the Masawoy coastal waters were due to its habitat conditions in relatively good condition consisting of dead coral rubble, sand, coral live with seagrass vegetation dominated by Thalasia hemprizii and Enhalus acuroides. Meanwhile, habitat conditions at other locations have suffered a severe damage and dominated by dead coral. Environmental conditions in the study region were within the limits of decent support for the growth of macro alga. Keywords: macroalga, biodiversity, density, frequency, dominance, Ambalau

7 páginas, 1 tabla, 1 figura., Funding was provided to JM by Georgetown University and NSF grants No. 0316800, No. 0941487 No. 0918308, No. 0847922, No. 0820722, No. 9753044; and to Michael Kr¨ utzen, Lars Bejder and William Sherwin by SeaWorld Research and Rescue Foundation, National Geographic Society, Claraz-Schenkung, A.-H. Schultz Stiftung and Julius-Klaus Stiftung.

Coastal habitats having high productivity provide numerous ecological services such as foods, protection from strong waves through buffering effect, fixation of CO2 through photosynthesis, fostering biodiversity etc. However, increasing human impacts and climate change decrease or degrade coastal habitats. ASEAN region is developing most rapidly in the world. In the developing region, it is necessary to grasp present spatial distributions of habitats as a baseline data with standardized mapping methods. Remote sensing is one of the most effective methods for mapping. Japan Aerospace Exploration Agency (JAXA) provides non-commercial satellite images with ultra-high spatial resolution optical sensors (10 m), AVNIR2, similar to LANDSAT TM. Using ALOS AVNIR2 images it may be possible to make habitat map in the region. In Thailand, shrimp ponds cause degradation of coastal ecosystem through cutting mangroves and eutrophicated discharge from ponds. We examined capability of remote sesing with ALOS AVNIR2 to map seagrass beds in Khung Kraben Bay, Chanthaburi Province, Thailand, surrounded by shrimp ponds. We analyzed ALOS AVNIR2 taken on 25 January 2008. Ground truth survey was conducted in October 2010 using side scan sonar and scuba diving. The survey revealed that there were broad seagrass beds consisting of Enhalus acroides. We used a decision tree to detect seagrass beds in the bay with quite turbid seawater coupled with Depth-Invariant Index proposed by Lyzenga (1985) and bottom reflectances. We could succeed to detect seagrass beds. Thus it is concluded that ALOS AVNIR2 is practical to map seagrass beds in this region.

Two distinctly different but representative seagrass communities were studied in the vicinity of Koror, Palau, Western Caroline Islands from May 21 to June 25 1978. The first community, a 30 m wide band adjacent to a beach, consisted primarily of Halodule uninervis (Forsk.) Aschers. and Cymodocea rotundata Ehrenb. and Hempr. ex Aschers. near the shore (Zone 1), then Thalassia hemprichii (Ehrenb.) Aschers. and Syringodium isoetifolium (Aschers.) Dandy (Zone 2) with T. hemprichii, C. rotundata and Halophila ovalis (R. Br.) Hook.f. at the seaward margin (Zone 3). The second site was an extensive tidal flat dominated by Enhalus acoroides (L.f.) Royle and T. hemprichii (Zone A). On the deeper seaward slope of this flat (Zone B), T. hemprichii disappeared while C. serrulata (R.Br.) Aschers. and Magnus appeared as depth increased. Enhalus density remained about the same in Zones A and B although the blades were larger (averaging 76 cm long and 2.1 cm wide) in Zone B than in Zone A (averaging 45 cm long and 1.5 cm wide). Blade elongation rates ranged from 1.2 to 3.0 cm week−1 for T. hemprichii with high variance and approximately 7.0 cm week−1 for Enhalus. Enhalus had a maximum blade elongation rate of over 2 cm day−1. All the broad-bladed seagrasses were grazed by fishes, presumably scarids and siganids, but grazers did not consume a significant amount. Fish grazing was almost entirely concentrated at the heavily epiphytized blade tips especially those of Enhalus. Infauna samples at both sites were dominated by polychaetes and bivalves and the total number of individuals increased as the seagrass biomass increased. Epifaunal macroinvertebrates (especially sponges, scleractinians, prosobranchs and ascidians) were particularly abundant in shallow Enhalus beds and thick subtidal Thalassia beds. The common macroalgae present at the two sites differed considerably except for the almost ubiquitous Amphiroa fragilissima (L.) Lamour.

The distribution of the seagrasses of Papua New Guinea is described. Eight species are widely distributed, while three species are apparently restricted to the Daru area, and one form, of unknown taxonomic status, has only been found on the Solomon Sea coast of New Guinea. Studies on zonation, leaf width variation and leaf growth rates of Enhalus acoroides (L. f. ) Royle are reported. In most Papua New Guinea seagrass meadows, Enhalus has a wide depth range exceeded only by that of Thalassia hemprichii (Ehrenb.) Aschers. Leaf width appears to be mainly a function of shoot age. The maximum leaf growth rate recorded was 2.23 cm/day with a mean of 1.22 cm/day. A hypothesis to explain the fast, continuous leaf growth strategy of Enhalus , and seagrasses in general, is suggested. It is proposed that this strategy is a response to a shading-damage-nutrient-filtering effect due to the epiflora and epifauna which colonize the leaves. It is suggested that this effect restricts the photosynthetically useful life of a leaf segment to less than 25 days. This limited photosynthetically active life results in a “race” in which the seagrass must produce new photosynthetic tissue faster than it can be rendered inactive by epiphytes.

Tropical seagrasses that are distributed in shallow sites and are likely to be exposed to air at low tides show greater tolerance of high temperatures than those which occur in deeper sites and remain submerged. Among seven genera that occur widely in tropical oceans, Enhalus and Halodule show the greatest heat tolerance and Syringodium the least, with Thalassodendron, Thalassia, Cymodocea and Halophila variously intermediate. Of two sympatric Cymodocea species, C. rotundata Ehrenb. & Hempr. ex Aschers. tolerates higher temperatures than does C. serrulata (R.Br.) Aschers. & Magnus. Within Halodule, narrow-leaved plants are more resistant to high temperature stresses than wide-leaved plants, and within the Halophila ovalis (R.Br.) Hook. f—H. minor (Zoll.) den Hartog complex, most small-leaved populations are more resistant to high temperatures than large-leaved populations. Although diverse leaf types may occur together within shallow seagrass beds, plants with narrow and/or small leaves predominate in sites that are most likely to be exposed to the high temperatures that may accompany low tides in the tropical oceans.

Threats to and loss of seagrass ecosystems globally, impact not only natural resources but also the lives of people who directly or indirectly depend on these systems. Seagrass ecosystems play a multi-functional role in human well-being, e.g. food through fisheries, control of erosion and protection against floods. Quantifying these services reveals their contributions to human well-being and helps justify seagrass conservation. There has been no comprehensive assessment as to whether seagrass ecosystem services are perceived to vary over the globe or amongst genera. Our study compiles the most complete list of ecosystem services provided by seagrasses so far, including bioregional- and genus-specific information from expert opinion and published studies. Several seagrass ecosystem services vary considerably in their (known) provision across genera and over the globe. Seagrasses genera are clearly not all equal with regard to the ecosystem services they provide. As seagrass genera are not evenly distributed over all bioregions, the presence of an ecosystem service sometimes depends on the genera present. Larger sized seagrass genera (e.g. Posidonia, Enhalus) are perceived to provide more substantial and a wider variety of ecosystem services than smaller species (e.g. Halophila, Lepilaena). Nevertheless, smaller species provide important services. Our findings point out data gaps, provide new insight for more efficient management and recommend caution in economic valuation of seagrass services worldwide.