Cymodocea Serrulata Research Articles

Simpanan Karbon Pada Padang Lamun di Kawasan Pantai Mengiat, Nusa Dua Bali

Human activity is the most contributor of carbon dioxide gas (CO2) to the air. The oceans have an important role in the carbon cycle, about 93% of the Earth's CO2 is stored in the oceans. Seagrass is one of sea plants that has a role as carbon sinks in ocean. Seagrass beds are able to absorb carbon by an average 0.21 tons/ha and the important species are Enhalus acoroide. The aim of this study is determine the carbon storage in seagrass at aboveground (leaf), belowground (roots and rhizomes) and carbon storage on each species of seagrass obtained at Mengiat coastal area. Determination of sampling point refer to seagrass density that used by purposive sampling. This method was assumed to represent or describe the condition of this area. This research used dry dyeing method which components sample was destruction with 500oC inside the furnace. The results showed that carbon storage of seagrass at belowground (root and rhizoma) is 25.70 gC/m2, and aboveground (leaf) is 17.18 gC/m2. Carbon storage at belowground is higher than aboveground because carbon will accumulate in the sediment. The type of seagrass that is obtained at Mengiat coastal area is Thalassodendron ciliatum, Thalassia hemprichii, Cymodocea serrulata, Halodule uninervis, Cymodocea rotundata, and Syringodium isoetifolium, the highest carbon storage are 62.46 gC/m2 is owned by Thalassodendron ciliatum, and the lowest carbon storages are 17.25 gC/m2 is owned by Syringodium isoetifolium.

Low Light Availability Alters Root Exudation and Reduces Putative Beneficial Microorganisms in Seagrass Roots.

Seagrass roots host a diverse microbiome that is critical for plant growth and health. Composition of microbial communities can be regulated in part by root exudates, but the specifics of these interactions in seagrass rhizospheres are still largely unknown. As light availability controls primary productivity, reduced light may impact root exudation and consequently the composition of the root microbiome. Hence, we analyzed the influence of light availability on root exudation and community structure of the root microbiome of three co-occurring seagrass species, Halophila ovalis, Halodule uninervis and Cymodocea serrulata. Plants were grown under four light treatments in mesocosms for 2 weeks; control (100% surface irradiance (SI), medium (40% SI), low (20% SI) and fluctuating light (10 days 20% and 4 days 100%). 16S rDNA amplicon sequencing revealed that microbial diversity, composition and predicted function were strongly influenced by the presence of seagrass roots, such that root microbiomes were unique to each seagrass species. Reduced light availability altered seagrass root exudation, as characterized using fluorescence spectroscopy, and altered the composition of seagrass root microbiomes with a reduction in abundance of potentially beneficial microorganisms. Overall, this study highlights the potential for above-ground light reduction to invoke a cascade of changes from alterations in root exudation to a reduction in putative beneficial microorganisms and, ultimately, confirms the importance of the seagrass root environment – a critical, but often overlooked space.

Habitat Preference and Population Structure of Two Data Deficient Seahorse (Syngnathidae) Species

Ecological studies of seahorses are sparse in the Indian Ocean. The vulnerability of seahorses to overfishing and increased anthropogenic impacts on coastal habitats necessitates better management of wild seahorse populations that in turn requires understanding habitat preferences and population structure. The distribution patterns and population structure of two species of seahorse (Hippocampus fuscus and H. spinosissimus) were assessed for the first time in a tropical estuary in north-western Sri Lanka. Both species have previously not been studied in the wild and have not been known to occur in estuaries. H. fuscus was the more abundant and widely distributed species, and was significantly larger than H. spinosissimus. Both species had significant differences in size between sexes, and the mean height was towards the lower end of the range know for both species. Some sexually mature males were smaller than the size reported in the literature. Seahorses occurred in low densities with patchy distribution, with abundance being higher in areas with the seagrass species Enhalus acoroides and Cymodocea serrulata that appear to be the favored habitat of seahorses within the study area.

Multispectral Resampling of Seagrass Species Spectra: WorldView-2, Quickbird, Sentinel-2A, ASTER VNIR, and Landsat 8 OLI

Although spectrally different, seagrass species may not be able to be mapped from multispectral remote sensing images due to the limitation of their spectral resolution. Therefore, it is important to quantitatively assess the possibility of mapping seagrass species using multispectral images by resampling seagrass species spectra to multispectral bands. Seagrass species spectra were measured on harvested seagrass leaves. Spectral resolution of multispectral images used in this research was adopted from WorldView-2, Quickbird, Sentinel-2A, ASTER VNIR, and Landsat 8 OLI. These images are widely available and can be a good representative and baseline for previous or future remote sensing images. Seagrass species considered in this research are Enhalus acoroides (Ea), Thalassodendron ciliatum (Tc), Thalassia hemprichii (Th), Cymodocea rotundata (Cr), Cymodocea serrulata (Cs), Halodule uninervis (Hu), Halodule pinifolia (Hp), Syringodum isoetifolium (Si), Halophila ovalis (Ho), and Halophila minor (Hm). Multispectral resampling analysis indicate that the resampled spectra exhibit similar shape and pattern with the original spectra but less precise, and they lose the unique absorption feature of seagrass species. Relying on spectral bands alone, multispectral image is not effective in mapping these seagrass species individually, which is shown by the poor and inconsistent result of Spectral Angle Mapper (SAM) classification technique in classifying seagrass species using seagrass species spectra as pure endmember. Only Sentinel-2A produced acceptable classification result using SAM.

Colonizing tropical seagrasses increase root exudation under fluctuating and continuous low light

AbstractWhile light availability plays a critical role in seagrass growth and distribution, there is limited understanding of how changes in light exposure impact belowground processes. We investigated the effect of prolonged and fluctuating reductions in light on root growth and exudation by three colonizing seagrasses: Cymodocea serrulata, Halophila ovalis, and Halodule uninervis. Seagrasses were grown in mesocosms under continuous full light (control), under continuous light reduction (medium or low), or under fluctuating light (10 d of low and 4 d of high light, repeated three times). Plants were harvested (1) 6 weeks after light treatments (impact), and (2) after an additional 4 weeks of continuous full light (recovery). Root exudates were collected from trap solutions and measured for dissolved organic carbon (DOC), total dissolved nitrogen (TDN), and dissolved organic matter (DOM) excitation/emission fluorescence spectroscopy. Root biomass decreased in all shading treatments. The most notable impact of light treatment was an increase in root exudation of DOC, protein‐like DOM and humic‐like DOM under fluctuating light for all species. After 4 weeks of recovery, exudation of DOC, and protein‐like DOM observed under fluctuating light returned to the control light levels. However exudation of DOC and protein‐like DOM by H. ovalis grown in continuous low light remained greater than the control, likely due to root death. This study suggests the belowground environment of seagrasses is sensitive to light reduction. Monitoring changes in root exudation of seagrasses can provide an effective and rapid method to assess light stress and short‐term recovery of seagrasses.

Short communication: Seagrass diversity and carbon sequestration: Case study on Pari Island, Jakarta Bay, Indonesia

Husodo T, Palabbi SDG, Abdoellah OS, Nurzaman M, Fitriani N, Partasasmita P. 2017. Seagrass diversity and carbon sequestration: Case study on Pari Island, Jakarta Bay, Indonesia. Biodiversitas 18: 1596-1601. Pari Island is located in Kepulauan Seribu chain. As a tourist destination, the seagrass ecosystem at the island is constantly under pressure from time to time. An effort to prevent widespread damage is to designate parts of the coastline as a limited access research centre. Efforts to study seagrass ecosystem on Pari Island are ongoing, including studies on seagrass' ability to sequestrate carbon. This quantitative study was conducted in December 2014. Surveys are done on the abundance and density of seagrass in 122 plots (area = 50 × 50 cm2) which spread in 6 research stations. Biomass measurements were performed by extractive method on 4 types of seagrass (Cymodocea serrulata, Halophila ovalis, Halodule uninervis and Syringodium isoetifolium). The assessment of seagrass capability in storing carbon has been done by measuring the primary productivity of above ground and below ground, while the amount of carbon released is measured from littered leaves and the leaves eaten by herbivores.The findings show that there are 7 of 12 species of seagrass identified in Indonesia, i.e. Cymodoceae rotundata, Cymodoceae serrulata, Thalassia hemprichii, Enhalus acoroides, Syringodium isoetifolium, Halodule uninervis and Halophila ovalis. The dominant species is Thalassia hemprichii (density 200±153, 261±107 and 117±52 stands/m2) and Halodule uninervis (82±59 stands/m2).Seagrass’ carbon sequestration capacity in the waters surrounding Pari Island, Jakarta Bay, is approximately 0.006-1.048 gC/m2/day whereas carbon reserves are between 0.24-346.10 gC/m2.

Keanekaragaman dan Kerapatan Rumput Laut Alami Perairan Pulau Serangan Denpasar Bali

Serangan Island was a costal area located in the Serangan village, South Denpasar district, near with Sanur and Nusa Dua tourism area. Serangan beach has a biodiversity such as natural macroalgae. This study was conducted in January 2017 at the seaweed cultivation area with the aims of research were to know the variety and density of macroalgae. The method used was a 1x1 m quadrat transect. Sampling was carried out during low tide. Macroalgae found in the area, consist of 12 species namely Ulva lactuca, Chaetomorpha linum. Chaetomorpha aera, Padina australis, Sargassum fluitans, Turbinaria ornate, Gelidium sp., Hypnea cornuta, Hypnea spicifera, Gracilaria salicornia, Acanthophora spicifera, Halimeda opuntia. Those species were belonging to 3 divisi namely Chlorophyta, Phaeophyta, Rhodophyta. The highest density of macroalgae was Padina australis while the lowest density was Chaetomorpha linum. Type of dominated macroalgae was from a group of Phaeophyta (brown algae) with highest dominance from the species of Padina australis. Water quality namely acidity (pH) was in the range of 7.54 to 7.75, salinity of 31.33-32.00 ppt, the water temperature was 26.50-27.30? C, which all was categorized as the optimal parameters for the growth of macroalgae. Assosiation of biota found were 9 species namely fish of larva, Cypraea lynx (Molusca), Emerita sp., Halodule sp., Synapta maculate, Enhalus acoroides, Cymodocea serrulata, Hermit crab, Ophiuroidea sp. The conditions coastal waters substrate was varied from white sand stone type to stony type by coral pieces.

Optimum Temperatures for Net Primary Productivity of Three Tropical Seagrass Species.

Rising sea water temperature will play a significant role in responses of the world's seagrass meadows to climate change. In this study, we investigated seasonal and latitudinal variation (spanning more than 1,500 km) in seagrass productivity, and the optimum temperatures at which maximum photosynthesis and net productivity (for the leaf and the whole plant) occurs, for three seagrass species (Cymodocea serrulata, Halodule uninervis, and Zostera muelleri). To obtain whole plant net production, photosynthesis, and respiration rates of leaves and the root/rhizome complex were measured using oxygen-sensitive optodes in closed incubation chambers at temperatures ranging from 15 to 43°C. The temperature-dependence of photosynthesis and respiration was fitted to empirical models to obtain maximum metabolic rates and thermal optima. The thermal optimum (Topt) for gross photosynthesis of Z. muelleri, which is more commonly distributed in sub-tropical to temperate regions, was 31°C. The Topt for photosynthesis of the tropical species, H. uninervis and C. serrulata, was considerably higher (35°C on average). This suggests that seagrass species are adapted to water temperature within their distributional range; however, when comparing among latitudes and seasons, thermal optima within a species showed limited acclimation to ambient water temperature (Topt varied by 1°C in C. serrulata and 2°C in H. uninervis, and the variation did not follow changes in ambient water temperature). The Topt for gross photosynthesis were higher than Topt calculated from plant net productivity, which includes above- and below-ground respiration for Z. muelleri (24°C) and H. uninervis (33°C), but remained unchanged at 35°C in C. serrulata. Both estimated plant net productivity and Topt are sensitive to the proportion of below-ground biomass, highlighting the need for consideration of below- to above-ground biomass ratios when applying thermal optima to other meadows. The thermal optimum for plant net productivity was lower than ambient summer water temperature in Z. muelleri, indicating likely contemporary heat stress. In contrast, thermal optima of H. uninervis and C. serrulata exceeded ambient water temperature. This study found limited capacity to acclimate: thus the thermal optima can forewarn of both the present and future vulnerability to ocean warming during periods of elevated water temperature.

PHYTOCHEMISTRY AND ETHNOPHARMACOLOGY OF THE SEA GRASS CYMODOCEACEA FAMILY– A REVIEW

Cymodoceaceae is a family of flowering plants, sometimes known as the “manatee-grass family,” the family Cymodoceaceae includes only marine species. The angiosperm phylogeny II system, of 2003 (unchanged from the APG system, of 1998), does recognize Cymodoceaceae and places it in the order Alismatales, in the clade monocots. They are marine hydrophytes that grow and complete their life cycle in a submerged condition, in a saline environment. Like terrestrial plant they obtain their energy from light through photosynthesis thus, they grow only in clear and shallow water, and at the suitable condition, they form beds or meadows. The family includes five genera, totalling 16 species of marine plants occurring in tropical seas and oceans (so-called seagrasses). Cymodoceaceae consist of five genera such as Amphibolis, Cymodocea, Halodule, Syringodium, and Thalassodendron. In this genera Cymodocea rotundata Ehrenb. and Hempr. Ex Asch. Cymodocea serrulata, (R.Br.) Asch. and Magnus, Halodule pinifolia (Miki) Hartog, Halodule uninervis (Forssk.) Asch and Syringodium isoetifolium (Asch.) are the species mostly adopted in Indian coastal region. These seagrass species have unique nature and wide application to the environment including human being. In this article botanical aspects, phytochemistry and ethnopharmacology of these five seagrass species belong to Cymodoceaceae family will be discussed.

Seagrass community structure of Tayando-Tam Island, Southeast Moluccas, Indonesia

Fitrian T, Kusnadi A, Persilette RN. 2017. Seagrass community structure of Tayando-Tam Island, Southeast Moluccas, Indonesia. Biodiversitas 18: 788-794. Seagrass bed is one of the marine ecosystem that having the highest productivity that could sustain coastal resources. The research purposes of this paper is to determine the community structure of seagrass at Tayando-Tam Island, Southeast Moluccas, Indonesia. The method of observation of seagrass bed using a line transect, transect ran perpendicular to the shore line for 100 meters. The field of observations include identification of seagrass species, counting the number of shoots and percentage (%) of seagrass cover. Seven species of seagrass had been found in Tayando-Tam island, i.e. Enhalus acoroides, Thalassia hemprichii, Cymodocea serrulata, Cymodocea rotundata, Halodule pinifolia, Halophila ovalis, Syringodium isoetifolium. Halodule pinifolia had the highest density in Tam Island with the number of 684.18 shoots/m2. The coverage in this area was between 4.64-43.1 %. Based on the number of species, diversity index and dominance index Tam Island had the most stable seagrass communities, with moderate value of diversity index (H'=1.26), high evenness Index (E=1.63), and low value of dominance index (D=0.34). Seagrass resources in the Tayando-Tam islands is good and the potential for biota the association, which is supported by the quality of water is good for the growth of seagrass.

KERAGAMAN LAMUN DI TELUK BANTEN, PROVINSI BANTEN

Ekosistem lamun merupakan salah satu penyusun pantai tropis yang memiliki peranan penting dalam struktur ekologi wilayah pesisir, selain itu lamun juga diketahui memiliki potensi dimanfaatkan sebagai bahan baku farmasi, sehingga keberadaan lamun di suatu wilayah sangat penting untuk diketahui dan dianalisis. Penelitian ini dilakukan dengan metode transek garis pada tiga stasiun, dan bertujuan untuk memberikan informasi keragaman, kerapatan, dan penutupan jenis lamun di Teluk Banten. Padang lamun di Teluk Banten terdiri dari lima jenis, yaitu: Cymodocea rotundata, Cymodocea serrulata, Enhalus acoroides, Halophila ovalis, dan Thalassia hemprichii. Kerapatan lamun tertinggi ditemukan di Pulau Tunda (193 individu/m2), dan terendah di Pulau Panjang (44 individu/m2). Penutupan lamun terendah ditemukan pada Pulau Panjang (62.5%), sedangkan tertinggi pada Pulau Kalih (90%), dan didominasi oleh jenis Enhalus acoroides. Nilai penutupan lamun ini menunjukan ekosistem lamun di Teluk Banten tergolong sehat/kaya.

Diversity and distribution of seagrasses in the Union of the Comoros

This study represents the first in situ assessment of seagrasses in the Union of the Comoros. The presence of the following 10 species (ranked in order of abundance) was confirmed: Thalassia hemprichii, Thalassodendron ciliatum, Syringodium isoetifolium, Halodule wrightii, Cymodocea rotundata, Cymodocea serrulata, Halodule uninervis, Halophila ovalis, Zostera capensis and Enhalus acoroides. Seagrasses occurred in large, continuous beds in the shallow waters at the northern and southern tips of Grande Comore Island and around the Bimbini Peninsula on western Anjouan Island, but were sparsely distributed throughout the shallow waters surrounding Mohéli Island.

Differential methods of localisation of fungal endophytes in the seagrasses

ABSTRACTSections of three seagrass species (Halophila ovalis, Cymodocea serrulata and Halodule pinifolia) were assessed for endophytes based on differential staining using light and fluorescence microscopy method. Acridine orange and aniline blue detected endophytic fungi in 20% and 10% of the segments, respectively, whereas lactophenol cotton blue was more sensitive to detect the fungal hyphae in 70% of the segments. Hyphae were the principal fungal structures generally observed under the cuticle, within the epidermal cells, mesophyll (Parenchyma) cells and occasionally within the vascular tissue that varied in type, size and location within the leaf tissue. Present study also recorded the sporulation for the first time from the seagrass endophytes. Successfully amplified products of the ITS region of endophytic fungal DNA, directly from seagrass tissue and also from culture-dependent fungal DNA clearly depicted the presence of endophytic fungi in H. ovalis with two banding patterns (903 and 1381 bp) confirming the presence of two dominant fungal genera. The fingerprinting of endophytic fungal community within the seagrass tissue was assessed using denaturing gradient gel electrophoresis (DGGE) that derived with multiple bands that clarified the presence of more than one taxon within the seagrass tissue.

Fiber Characteristics and Papermaking of Seagrass Using Hand-beaten and Blended Pulp

Marine angiosperms could inevitably offer considerable potential resources for their fiber, yet little research has been conducted, especially in Malaysia. Fiber characteristics of five species of seagrass – Enhalus acoroides, Cymodocea serrulata, Thalassia hemprichii, Halophila ovalis, and Halophila spinulosa – were evaluated. Fiber dimensions were studied to determine slenderness ratio, flexibility coefficient, Runkel’s ratio, and Luce’s shape factor species selection. The seagrass species have the potential in papermaking production as they possessed slenderness ratio >33 (98.12 to 154.08) and high Luce’s shape factor (0.77 to 0.83); however the species exhibited low flexibility coefficient 1 Runkel’s ratio (1.11 to 1.60), which indicate rigid fiber. The five seagrass species have high cellulose >34% (40.30 to 77.18%) and low lignin content <15% (5.02 to 11.20%), which are similar to those encountered in non-wood plant species. Handmade paper sheet of Enhalus acoroides using pulp subjected to mechanical blending exhibited the highest tensile strength (4.16 kN/m) compared to hand-beaten pulp (3.46 kN/m). The highest breaking length (3.43 km) was achieved by a paper sheet of Thalassia hemprichii using hand-beaten pulp. Based on their physical and chemical composition properties, seagrass have potential as sources of fibrous material for handmade papermaking.

SIMPANAN KARBON PADANG LAMUN DI KAWASAN PANTAI SANUR, KOTA DENPASAR

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.

Thresholds for morphological response to light reduction for four tropical seagrass species

Seagrasses worldwide are highly vulnerable to, and at increasing risk from reduced light availability, and robust light thresholds are required for evaluating future impacts of changing light conditions. We tested the morphological response (shoot density and growth) of four Indo-West Pacific seagrass species (Cymodocea serrulata, Halodule uninervis, Halophila ovalis and Zostera muelleri) to six daily light levels ranging from 0 to 23molm−2d−1 (0–70% surface irradiance) in cool (∼23°C) and warm temperatures (∼28°C) over 14 weeks. The impact of light limitation on shoot densities and growth rates was higher at warm than at cool temperatures, and for Z. muelleri and H. ovalis than for C. serrulata and H. uninervis, in terms of both the time taken for the low light treatment to take effect and the predicted time to shoot loss (e.g. 17–143 days at 0molm−2d−1). Using fitted curves we estimated temperature-dependent thresholds (with estimates of uncertainty) for 50% and 80% protection of growth and shoot density, defined here as “potential light thresholds” in recognition that they were derived under experimental conditions. Potential light thresholds that maintained 50% and 80% of seagrass shoot density fell within the ranges 1.1–5.7molm−2d−1 and 3.8–10.4molm−2d−1, respectively, depending on temperature and species. Light thresholds calculated in separate in situ studies for two of the same species produced comparable results. We propose that the upper (rounded) values of 6molm−2d−1 and 10molm−2d−1 can be used as potential light thresholds for protecting 50% and 80% of shoot density for these four species over 14 weeks. As management guidelines should always be more conservative than thresholds for biological declines, we used error estimates to provide a quantitative method for converting potential light thresholds into guidelines that satisfy this criterion. The present study demonstrates a new approach to deriving potential light thresholds for acute impacts, describes how they can be applied in management guidelines and quantifies the timescales of seagrass decline in response to light limitation. This method can be used to further quantify cumulative impacts on potential light thresholds.

Light Levels Affect Carbon Utilisation in Tropical Seagrass under Ocean Acidification.

Under future ocean acidification (OA), increased availability of dissolved inorganic carbon (DIC) in seawater may enhance seagrass productivity. However, the ability to utilise additional DIC could be regulated by light availability, often reduced through land runoff. To test this, two tropical seagrass species, Cymodocea serrulata and Halodule uninervis were exposed to two DIC concentrations (447 μatm and 1077 μatm pCO2), and three light treatments (35, 100, 380 μmol m-2 s-1) for two weeks. DIC uptake mechanisms were separately examined by measuring net photosynthetic rates while subjecting C. serrulata and H. uninervis to changes in light and addition of bicarbonate (HCO3-) use inhibitors (carbonic anhydrase inhibitor, acetazolamide) and TRIS buffer (pH 8.0). We observed a strong dependence on energy driven H+-HCO3- co-transport (TRIS, which disrupts H+ extrusion) in C. serrulata under all light levels, indicating greater CO2 dependence in low light. This was confirmed when, after two weeks exposure, DIC enrichment stimulated maximum photosynthetic rates (Pmax) and efficiency (α) more in C. serrulata grown under lower light levels (36–60% increase) than for those in high light (4% increase). However, C. serrulata growth increased with both DIC enrichment and light levels. Growth, NPP and photosynthetic responses in H. uninervis increased with higher light treatments and were independent of DIC availability. Furthermore, H. uninervis was found to be more flexible in HCO3- uptake pathways. Here, light availability influenced productivity responses to DIC enrichment, via both carbon fixation and acquisition processes, highlighting the role of water quality in future responses to OA.

In vitro and in vivo efficacy of partially purified herbal extracts against bacterial fish pathogens

The effect of partially purified extracts of sea grass (Cymodocea serrulata), turmeric (Curcuma longa), Spirulina (Spirulina platensis), and beet root (Beta vulgaris) on the antimicrobial, antioxidant, and hemato-biochemical changes in ornamental dotty back, Pseudochromis dilectus against isolated fish bacterial pathogens (Proteus mirabilis, Bacillus pumilus, and Staphylococcus sciuri) under in vitro and in vivo conditions is reported. Among the extracts turmeric extract exhibited significant antibacterial activity. The extract possesses the highest antioxidant property and phenol content; the GC–MS analysis revealed the highest presence of Ar-turmerone (42.85%) and Curlone (18.80%). The potential fractions possess reducing power and free radical scavenging activity. The mortality against P. mirabilis at doses of 2.5×108 and 2.5×108CFU was 100% whereas against S. sciuri (2.5×107 and 2.5×108) it was 70 and 80%. The highest bacterial load was observed in kidney (3.1×107CFU/g) and liver (2.6×108CFU/g) against P. mirabilis. The LD50 study suggested that all the fish die at doses of 2.5×107 (CFU/fish) and 2.5×108 (CFU/fish) after 15days of challenge with P. mirabilis. Among the purified sub fractions, the sub-fraction II (F-II) at 5 and 10mg/ml resulted in elevated levels of WBC and RBC, lymphocytes, and neutrophils; further the percentage of monocytes and granulocytes, total protein, total lipid, and glucose also increased significantly. At 1mg/ml the relative percent survival (RPS) was 100% in sub-fraction II (F-I) group as in control. With 5mg/ml in F-I and 1mg/ml in F-II group the RPS was 94%; however, in 10mg/ml of F-I and 5mg/ml of F-II groups the RPS declined to 89%. The lowest mortality of RPS (79%) was observed in 10mg/ml in F-II group. The present results suggest that the partially purified turmeric extract elevated antimicrobial and antioxidant activities by improving the hemato-biochemical profiles and survival rate in P. dilectus against P. mirabilis. Statement of relevanceThe success of any fish culture depends on the health status of cultivated species. Fish diseases are one of major threats in aquaculture industry inflicting heavy mortality in the world. To prevent and control of the diseases traditionally was used several antibiotics or chemicals during the last few decades. However, these methods have been criticized for their negative impacts such as accumulation of drugs in tissues, development of drug resistance, and immunosuppression. Several herbal and their active principles possess better antioxidant activity, phenols content, reducing power, and free radical scavenging activity. Therefore in the present study was isolated new fish pathogen from the infected fish and to investigated antioxidant activity and their pathogenicity and hematological changes in dotty back, P. dilectus against P. mirabilis. This work is novel in aquaculture to design or prepare cost effective drug or feed for fishes.

Remote underwater video reveals grazing preferences and drift export in multispecies seagrass beds

The leaf tethering method has frequently been applied in the quantification of herbivory in seagrass beds. The major limitation of this method is the inability to differentiate between biomass that is consumed versus exported as drift, particularly from thin-leaved seagrass species, due to leaf damage caused by grazers. The loss of leaf biomass to herbivory and the export of four tropical seagrass species (Thalassia hemprichii (TH), Cymodocea rotundata (CR), Cymodocea serrulata (CS), and Halodule uninervis (HU)) by drift were quantified using the tethering method with remote underwater video (RUV) in multispecies seagrass beds at Dongsha Island in the South China Sea. The diversity of grazers, and the forage preferences for each of the four seagrass species were also recorded. Most seagrass herbivory (>75%) was due to parrotfish (Leptoscarus vaigiensis and Calotomus spinidens); both juvenile and adult parrotfish preferred the fast-growing HU, but adult parrotfish apparently fed more on the more nutrient-rich TH and CS than the juveniles. The thin-leaved HU had higher relative biomass loss to grazing (74%) and drifting (13%) per day than the other species. Collectively our estimates suggest that 16% and 2% of daily production of local seagrass beds were lost due to grazing and drift export, respectively. Compared to the total loss of biomass due to grazing, the total loss due to drifting biomass was minor.

Structural characterization, antioxidant and in vitro cytotoxic properties of seagrass, Cymodocea serrulata (R.Br.) Asch. & Magnus mediated silver nanoparticles

The present study pertains to the synthesis, structural elucidation, antioxidant and in vitro cytotoxic properties of silver nanoparticles (AgNPs) from marine angiosperm, Cymodocea serrulata aqueous extract (CSAE). The characterization was made through UV–Visible spectroscopy (UV–Vis), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), zeta potential and dynamic light scanning (DLS) analyses. The UV–Vis spectrum resulted in a strong surface plasmon resonance (SPR) at 430nm. The average crystalline size of the AgNPs was predicted through XRD peaks that indicated the 2 theta values of 37.84°, 44.06°, 64.42° and 77.74° for Bragg's refraction index. The functional groups responsible for the bio-reduction of Ag+ into Ag0 were focused through FTIR spectrum. The FESEM images showed that the C. serrulata mediated AgNPs (CS-AgNPs) were spherical in shape. DPPH assay revealed the higher free radical scavenging activity in CS-AgNPs, when compared to CSAE. The cytotoxicity assay on the cervical cancer (HeLa) and African green monkey kidney (Vero) cells upon treatment with CSAE: 107.7 & 124.3μgml−1 and CS-AgNPs: 34.5 & 61.24μgml−1, respectively showed good inhibition rate. These findings highlight the fact that C. serrulata could be a potential source for developing potent drugs and further studies are needed.