Mangrove Environment Research Articles

Exchange between macrophyte and mangrove organic matter input in estuarine systems: drought implications

Paq proxy was applied on mid and long-chain n-alkanes in order to develop an index to assist in the long-term assessment of changes and exchanges between aquatic communities in estuarine environments as a result of increased saline incursion. New boundaries are proposed according to n-alkanes abundance in the leaves of local mangrove tree species for better definition of emergent aquatic plant end-member. Molecular distribution and δ13C isotopic signatures of n-alkanes were also used to support the parameter. A predominance of odd carbon-numbered long chain (> C27 n-alkanes) indicated a main terrestrial input, although mid-chain n-alkanes (23 and 25 carbons) were also identified. Short-chain n-alkanes (< 19) were absent or found in a very small concentration. Carbon Preference Index and C/N ratio reinforced a terrestrial origin for the sedimentary organic matter. δ13C signatures of n-alkanes for C23, C25, C29 and C31 were characteristic of mangrove input, ranging from -27.57 ‰ (C23) to -34.40 ‰ (C29) for Piraquê-Mirim River (PM) and from -27.36 ‰ (C23) to -32.84 ‰ (C31) for Piraquê-Açu River (PA) without any particular trend. Paq proxy was successfully used to identify rises in marine macrophytes (mid-chain n-alkanes) input mainly in the confluence and PM probably as consequence of drought periods. The confluence presented a mixing sources of OM. PA was identified as a stable mangrove environment while PM was characterized by pulses of marine macrophytes input and should be managed with care in respect to its catchment for water use and dam constructions as a shortage of fresh water can alter the estuarine ecology.

Adaptability and growth performance of Avicennia marina seedling within Silvofishery pond

The application of silvofishery pond raised the question on the suitability of particular mangrove species to be integrated. This research aimed to study the survival and growth rate of Avicennia marina seedling within silvofishery pond, to analyze its growth performance compared to its natural habitat and to determine the appropriateness of A. marina plantation in the silvofishery pond. Experiment was designed to apply variation of mangrove composition, including pure (monoculture) and mixed (polyculture) mangrove species. The experiment was conducted for a year involving 5 observations periods to 27 expected samples with 3 months interval. Data collection was conducted to seedling survival, height and diameter. The result showed low survival of A. marina during the research. Survival of A. marina in pure (monoculture) treatment was fluctuated among periods with the ranged of 1 – 7 stands, while in the mixed (polyculture) treatment was ranged from 1 – 3 stands. Average height growth was higher in the pure (monoculture) treatment with 41.94 mm.month-1, 96.43 mm/month, 95.60 mm/month and 39.56 mm/month compared to 41.94 mm/month, 50.55 mm/month, 41.21 mm/month and 37.91 mm/month in the mixed (polyculture) treatment respectively for the first, second, third and forth periods. While the diameter growth was fluctuated. This result indicated better growth performance compared to previous researches. This research concluded that mangrove silvofishery pond environment is not suitable for the establishment of A. marina, even though it might provide a good growth performance. But, this species is not recommended for plantation in the pond due to its low survival which inhibit ecosystem establishment and expected environmental services.

Modern pollen–vegetation studies from the Sajnekhali Island Wildlife Sanctuary, Sundarbans, Eastern India

ABSTRACTModern pollen–vegetation studies are crucial for the calibration and interpretation of fossil pollen assemblages. In eastern India, knowledge regarding the relationship between pollen deposition and the modern-day vegetation is required to make use of fossil pollen data, which is still scant. To fill this gap, the present study deals with the pollen analysis of 20 surface sediment samples from the Sajnekhali Island Wildlife Sanctuary, Sundarbans, India. The palynological results show that 20 genera in 18 families are identified, of which 16 major pollen taxa are recorded under mangrove and its associate groups. To understand potential drivers changing pollen abundance in the surface samples, a detrended correspondence analysis (DCA) is conducted to typify the environmental gradients among samples. The DCA of the modern pollen assemblages reveals the taxa defining the environmental gradient from inland to the margin of the island. The primary gradient appears to be the salinity tolerance of mangroves from near the water margin to the less salt-tolerant taxa. Axis 1 describes 62.5% of the variance in the dataset. The secondary axis appears to describe the gradient in subtaxa away from the mangrove. Axis 2 describes 4.5% of the variance in the dataset. Rhizophora mucronata, Avicennia marina, Sonneratia apetala, Excoecaria agallocha, Heritiera fomes, Bruguiera gymnorrhiza, Xylocarpus granatum and Nypa fruticans are recorded as the dominant pollen taxa that follow a salinity gradient. All modern pollen rain appears compatible with the actual floristics of the area. Thus, the present study indicates that the mangrove environment is well represented in the pollen record and displays close linkages between pollen composition and native parent plants in the area. This pollen dataset fills an information gap and is useful in understanding and interpreting the palaeoecology and palaeoenvironment of tropical marshes of similar environments.

Did mangrove communities exist in the Late Cretaceous of the Kristianstad Basin, Sweden?

Previous inferences of oyster-dominated communities occupying mangrove-like depositional settings in the Kristianstad Basin, Sweden, during the late early Campanian are reassessed. A significant percentage of oysters (Acutostrea incurva) from the Belemnellocamax mammillatus zone in Bed 3 at Åsen bear indentations on their left valves indicating attachment to plant axes. Many of these axes bear morphological features characteristic of the distal subaerial portions of woody plant branches and appear to have been rafted into the marine environment rather than representing in situ mangrove stems and roots. Foraminiferal assemblages recovered from sediment within the oyster body cavities differ from modern mangrove-community associations by the absence of siliceous agglutinated Foraminifera, the presence of diverse and relatively abundant Lagenida, relatively common triserial Buliminida, and a notable percentage of planktonic taxa. Chondrichthyan teeth assemblages from the same beds are similarly incompatible with the interpretation of a mangrove depositional environment based on comparisons with the distribution of related extant taxa. Apart from oyster shells and belemnite rostra, these beds are notably depauperate in diversity and abundance of macroinvertebrate remains compared with coeval carbonate shoal and rocky shoreline assemblages from the same basin. The collective palaeontological and sedimentological evidence favours an inner neritic sandy-substrate setting, but not nearshore or mangrove-like depositional environment for the oyster-rich Bed 3 at Åsen. The absence of mangrove-like assemblages at Åsen is consistent with the development of modern mangrove ecosystems much later (during the Maastrichtian and Cenozoic) based on the global palynological record.

Influence of sediment characteristics on density and distribution of Ocypodoid crab burrows (superfamily: Ocypodoidea) along the coastal areas of Pakistan

Crabs belong to the superfamily Ocypodoidea are a significant component of benthic fauna and considered as ecosystem engineers because of their dynamic role as an active burrower in mangrove and estuarine environment. The current investigation was to evaluate the crab burrow density, diameter and total area of burrow opening along the coast of Pakistan. The variations in burrow properties and their relation to sediment characteristics were also evaluated to recognize the most influencing variables of sediments that effects on crab burrows. All crab burrow and sediment characteristics differed significantly (p<0.05) among the monitoring sites. Regression analysis showed that crab density was significantly correlated with burrow density (P<0.001). Moreover, burrow density was noticed significantly greater (p<0.05) than crab density. Pearson correlation analysis reveals that moisture, porosity, organics, sand and mean grain size observed as most influencing the features of sediment to determine the ecological functioning of crab burrows in mangrove and mudflats of Pakistan.

Environmental assessment of a mangrove protected area in the southeast Gulf of Mexico through sediment core analysis

Three sediment cores were collected from different regions of the mangrove adjacent to Carmen Island, in Terminos Lagoon, to examine the influence that natural processes, the oil industry and urban development exert upon the mangrove environment. Textural and chemical characteristics were evaluated in each core. The variations among them reflect the different dynamic and depositional conditions for each site. Core C1, located near Puerto Real inlet, presents higher averages of grave l (16%), silt (32.6%), clay (1.48%), organic carbon (4.42%), carbonates (49.9%), CaO (28.96%), MgO (1.7%), P2O5 (0.99%) and Cu (4.46 mg/kg), some of these elements linked to the abundance of organisms in the area. Located in a channel with high sand content formed by an ancient delta, core C2 presents the highest average concentration of Al2O3 (4.39%), Fe2O3 (1.1%), MnO (0.02%), TiO2 (0.17%), Zn (14.8 mg/kg), Ni (16.9 mg/kg), Cr (293 mg/kg), V (12.3 mg/kg) and Cd (0.14 mg/kg), indicating high concentration of terrigenous sediments associated with heavy minerals. Situated in the lagoon border close to Carmen City, core C3 presents the highest sand (88.3%), SiO2 (64.5%), K2O (1.1%) and Pb (2.2 mg/kg) concentration. The location of this core makes it more susceptible to the dynamic processes that take place in the lagoon. The chemical differences observed in C2 are linked to the construction of Federal Highway 180. The drought that affected the basin during El Nino (1997–1998) produced a decrease in the rivers flow and a diminution of terrigenous sediments supply to Terminos Lagoon that is mainly observed in C3.

Isolate Actinomycetes SA32 Origin of Segara Anakan Mangrove Rhizosphere and its Capability in Inhibiting Multi-Drugs Resistant Bacteria Growth

The screening of antibiotic-producing actinomycetes from the mangrove environment is increasing to search for bioactive compounds capable of inhibiting the growth of Multi-Drugs Resistant (MDR) bacteria. The research aimed to isolate actinomycetes from mangrove mud rhizosphere in Segara Anakan lagoon that is capable of producing bioactive compounds inhibiting MDR bacterial growth, to characterize phenotypically along with 16S rRNA gene sequence, to cover out inhibition potencies toward MDR bacterial growth, and to characterize antibacterial compounds produced. Isolate actinomycetes SA32 was isolated from rhizosphere mud of Rhizophora mucronata from east Segara Anakan. It showed fragmented aerial mycelium similar to Streptomyces sp. NEAE-102; however, 16S rRNA gene sequence analysis yielded 96% similarity to Streptomyces sp. N56. In antagonism assay, it inhibited the growth of MDR bacteria Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Pseudomonas areuginosa, Enterococcus cloacae and Enterobacter sp. The diffusion antagonism assay results in the highest antibacterial activity against S. aureus with clear zone diameter 20 mm. The result of Minimum Inhibitory Concentration (MIC) assay showed that 20% crude extract has been able to inhibit the growth of MDR bacteria characterized by the decrease of turbidity. The antibacterial compound produced was not known yet but has an Rf value of 0.7-0.9 in the TLC test. Isolate actinomycetes SA32 is potent to be developed as an MDR antibacterial substance source and it is proposed as a new strain of Streptomyces.

Palaeoclimatic Evidences from the Quaternary Coastal Deposits, Southwestern, Nigeria

The studies on some samples retrieved from the coastal sediment deposit have been carried out. The palynological and geochemical indices were evaluated with the view of determining their chronology, palaeoclimatic conditions that prevailed during the time of their emplacement and also to re-asses the palaeoenvironment of the Lagos coastal deposit in Dahomey Basin. The identification of diagnostic species age entails the palynological analysis while the geochemical analysis determines the provenance of these Quaternary sediments. The occurrences of Laevigatosporites sp., Zonocostites ramonae, Acrostichum aureum in abundance along with few long ranging forms suggest that the vegetation development was under a humid climate and that the sediments were deposited during cooler and wetter conditions. The presence and high abundance of Crassoretitriletes vanraadshooveni, Zonocostites ramonae, Canthiumidites sp., Sapotaceoidaepollenites sp. and Pachydermitesdiederixi palynomorphs indicate an age range of late Pliocene (Gelasian) to early Pleistocene (Calabrian) (2.588 - 1.806 Ma). This age range is known to correspond to the 3.7 - 3.8 depositional cycles of relative change of coastal On-lap. The geochemical appraisal showed that the ratios of organic carbon-nitrogen (C/N) indicate that the sediments were sourced from aquatic, protein-rich and cellulose-poor milieu. The wetter climatic period has enhanced algae productivity as a consequence of greater wash-in of soil nutrients, and these periods are recorded as increased rate of organic carbon mass accumulation. Conversely, the dominance of a mangrove habitat, Zonocostites ramonae suggests a mangrove swamp environment which was the most prevalent environment of the Lagos lagoon in the Pleistocene.

Improving Silvofishery Management Through Seedling Growth – Environment Quality Dynamic Relation Analysis

&lt;p&gt;Mangrove plants are sensitive to environment condition. This research aimed to analyze the linkages of mangrove growth and environment dynamics and to estimate the growth of mangrove along with the environment dynamics. The research was conducted through the field experiment by the plantation of A. marina in silvofishery pond canals. Data collection was conducted for 18 months with 3 months observation interval. The environment variables observed including temperature, salinity, turbidity, pH, dissolved oxygen, TSS, sediment organic matter, nitrogen and phosphorus, and the growth of mangrove seedling. Analysis was conducted through regression and modelling with Powersim software. The result showed that the height growth was affected by dissolved oxygen, temperature, salinity, turbidity and pH, while the diameter growth was affected by TSS concentration. Inversely, the growth of mangrove also had a significant effect on temperature, change of organic matter and nutrient sediment concentration. Simulation showed that the height and diameter growth rates of A. marina seedling were dynamically changed among periods. Simulated seedling growth for one year forecast resulted in the rate of 0.115024 to 0.282294 cm/day for height and 0.001287 to 0.006031 cm/day for diameter. The simulation also indicated the continuous accumulation of organic matter and nitrogen over time. This research concluded that under limited environment dynamic, the growth of mangrove could be estimated. This model is a novelty in ecological studies. This research might initiates the more advanced ecological studies. Systematic estimation of ecosystem behaviour could be applied to formulate the best management practices, particularly in the silvofishery activities.&lt;/p&gt;

Economic Valuation of Urban Coastal Ecosystem Services and Scenic Beauty

A lagoon ecosystem provides a variety of ecological functions that directly or indirectly translate to economic services and values. The impact of the loss of cultural services is scarce in literature and particularly difficult to measure. This study generates monetary value for urban ecosystem services specifically the aesthetic value of a natural asset according to the perception of the adjacent community. The data were gathered by using a pre-structured, questionnaire-based personal interview carried out with 300 households representing 15 ‘Thotupola’ areas adjacent to the estuary. Choice Experiment (CE) was used to determine the preferences and the willingness to pay for conservation of urban ecosystem services and natural view. Highest value (530.75) was recorded for provisioning services. Marginal willingness to pay (MWTP) for prawns (272.25) was higher than the value of (258.50) crabs. Second highest MWTP (309.50) was acquired by recreation attribute, scenic beauty of the lagoon. Moreover, local fishing community does not willing to pay for regulatory services such as reduction of flood damage by mangrove and cleaning of polluted lagoon water. Understanding the degree and order of importance of ecosystem non-use values for its direct users is critical for planning for optimum and sustainable management, as properly managed ecosystem can provide continued returns to future generation without diminishing its productivity. The study generates information for decision makers with regard the monetary values for conservation of different ecosystem services and estuary view, to protect the estuary ecosystem through implementing policies and management plans, on urban estuaries and mangrove environment protection.

Isolation, structure elucidation and anticancer activity from Brevibacillus brevis EGS 9 that combats Multi Drug Resistant actinobacteria

Actinobacteria is the most widely distributed organism in the mangrove environment and produce a large amount of secondary metabolites. A new environmental actinobacterial stain exhibited strong antimicrobial activity against vancomycin and methicillin resistant actinobacteria. The active producer strain was found to be as Brevibacillus brevis EGS9, which was confirmed by its morphological, biochemical characteristics and 16S rRNA gene sequencing. It was deposited in NCBI GeneBank database and received with an accession number of KX388147. Brevibacillus brevis EGS9 was cultivated by submerged fermentation to produce antimicrobial compounds. The anti-proliferative agent was extracted from Brevibacillus brevis EGS9 with ethyl acetate. The bioactive metabolites of mangrove actinobacteria was identified by Liquid chromatography with mass spectrometry analysis. The result of the present investigation revealed that actinobacteria isolated from mangroves are potent source of anticancer activity. The strain of Brevibacillus brevis EGS9 exhibited a potential in vitro anticancer activity. The present research concluded that the actinobacteria isolated from mangrove soil sediment are valuable in discovery of novel species.

OCCURRENCE OF THE THREE SPOT GOURAMI Trichopodus trichopterus (ACTINOPTERYGII: OSPHRONEMIDAE) IN GUANABARA BAY, SOUTHEASTERN BRAZIL

A presença de Trichopodus trichopterus é registrada pela primeira vez habitando em manguezais na localidade de Porto do Rosa, município de São Gonçalo (22º47´S - 43º02´W), lado oriental da Baía de Guanabara, estado do Rio de Janeiro, Brasil. A espécie está aparentemente estabelecida na área, onde pode ter sido introduzida por atividades de aquariofilia. Os potenciais impactos ambientais desta introdução no ecossistema local, já sob estresse pela poluição e destruição de habitats, são discutidos.

Investigating monsoon and post-monsoon variabilities of bacterioplankton communities in a mangrove ecosystem.

In mangrove environments, bacterioplankton communities constitute an important component of aquatic biota and play a major role in ecosystem processes. Variability of bacterioplankton communities from Sundarbans mangrove, located in the Indian subcontinent in South Asia and sits on the apex of Bay of Bengal, was investigated over monsoon and post-monsoon seasons. The study was undertaken in two stations in Sundarbans using 16S rRNA clone library and Illumina MiSeq approaches with focus on the functionally important members that participate in coastal biogeochemical cycling. Out of 544 sequenced clones, Proteobacteria dominated the study area (373 sequences) with persistence of two major classes, namely, Gammaproteobacteria and Alphaproteobacteria across both monsoon and post-monsoon seasons in both stations. Several sequences belonging to Sphingomonadales, Chromatiales, Alteromonadales, Oceanospirillales, and Bacteroidetes were encountered that are known to play important roles in coastal carbon cycling. Some sequences showed identity with published uncultured Planctomycetes and Chloroflexi highlighting their role in nitrogen cycling. The detection of two novel clades highlighted the existence of indigenous group of bacterioplankton that may play important roles in this ecosystem. The eubacterial V3-V4 region from environmental DNA extracted from the above two stations, followed by sequencing in Illumina MiSeq system, was also targeted in the study. A congruency between the clone library and Illumina approaches was observed. Strong variability in bacterioplankton community structure was encountered at a seasonal scale in link with precipitation. Drastic increase in sediment associated bacteria such as members of Firmicutes and Desulfovibrio was found in monsoon hinting possible resuspension of sediment-dwelling bacteria into the overlying water column. Principal component analysis (PCA) revealed dissolved ammonium and dissolved nitrate to account for maximum variation observed in the bacterioplankton community structure. Overall, the study showed that a strong interplay exists between environmental parameters and observed variability in bacterioplankton communities as a result of precipitation which can ultimately influence processes and rates linked to coastal biogeochemical cycles.

Vertical distribution of living mangrove foraminifera from KwaZulu-Natal, South Africa

Modern foraminiferal assemblage zones can be used to reconstruct palaeo sea levels when applied to fossil foraminifera down a sediment core. Previous intertidal foraminiferal studies have predominantly focused on assemblages in surface sediments (0–1 cm), with the rationale that surface assemblages reflect the modern-day environment. Foraminifera live infaunally and therefore there is a need to document the infaunal vertical distribution of living foraminifera to fully capture the modern environment. Infaunal foraminiferal populations may compositionally differ from or be similar to those in the uppermost 1 cm of a core sample, but abundance is variable vertically, making it very complex to reconstruct and interpret past sea levels. This can have implications for the choice of assemblages to use as modern analogues for past sea-level reconstructions. This study documents the vertical infaunal distribution of living foraminifera, to allow for more informed interpretations of palaeo-reconstructions in mangrove environments. The down-core vertical distribution and abundance of living foraminifera, along with grain size and organic content, were documented using sediment cores along an elevational transect. Nine taxa were recorded as living at the time of collection, six of which were restricted to the top 4 cm. The majority of these were calcareous and found in the cores situated closer to the intertidal channel. Therefore, we argue that the diversity of living calcareous and agglutinated foraminifera could be restricted by grain size, with coarser grain sizes associated with lower species diversity. The findings suggest that foraminiferal species inhabiting the top 4 cm represent deeper living foraminiferal populations. Therefore, the top 4-cm interval can be used to establish a modern training set upon which reconstructions can be based. The findings from this study will provide guidance on the use of South African mangrove environments for future sea-level reconstructions.

Biosorption of lead (II) ion using &lt;i&gt;Penicillium citrinum&lt;/i&gt; KR706304 isolated from the mangrove soil environment of southeast Borneo.

The use of biological entities (fungi, bacteria, and algae) is considered to be a potential cost-effective and environmental friendly technique for heavy metals pollution sequestration. The present study aimed to isolate efficient lead tolerant fungi from mangrove soil environment and measure its capability for lead removal from aqueous solution. Lead tolerant fungal strains were isolated from soil samples using MEA (malt extract agar) amended with varied concentrations of lead ions (100-500 mg l-1 ). The most tolerant fungal strain was successfully isolated and identified molecularly as Penicillium citrinum KR706304 The isolated fungus was used for biosorption studies using malt extract broth (MEB) amended with lead ions. The effects of pH, temperature, initial metal concentration, biomass dose and age, agitation and contact time to the Pb(II) removal efficiency were monitored in the study. The results showed that the lead removal was optimal at concentration of 400 mg l-1 , maximum adsorption of 329±33.4 mg g-1 was observed at pH 7 and temperature of 30oC during the batch biosorption experiments. The optimal parameters for biomass dose, agitation speed, contact time and biomass age were 0.04 g l-1 , 150 rpm, 60 min and fifth day; respectively. The study revealed that the isolated Penicillium citrinum KR706304 has the potential to be used as a biosorbent for heavy metals particularly Pb(II) removal from the contaminated sites.Keywords: Fungi, Heavy metals, Lead(II) removal, Penicillium citrinum.

Draft Genome Sequence of Halophilic Hahella sp. Strain CCB-MM4, Isolated from Matang Mangrove Forest in Perak, Malaysia

ABSTRACTHahella sp. strain CCB-MM4 is a halophilic bacterium isolated from estuarine mangrove sediment. The genome sequence of Hahella sp. CCB-MM4 provides insights into exopolysaccharide biosynthesis and the lifestyle of the bacterium thriving in a saline mangrove environment.

Evaluation of antibacterial potential of mangrove sediment-derived actinomycetes

Actinomycetes are well-known as the source of bioactive metabolites. In this work, 16 out of 118 (13.6%) isolates of mangrove sediment-derived actinomycetes showed potential antibacterial activity against at least one bacterial strain. Five extracts from isolates AMA11, AMA12 and AMA21 exhibited a broad spectrum antibacterial activity against Staphylococcus aureus ATCC25923, Staphylococcus epidermidis ATCC35984, methicillin-resistant S. aureus (MRSA) SK1, Acinetobacter baumannii NPRC004 and Escherichia coli ATCC25922. Ethyl acetate extract from the cells of AMA11 (AMA11CE) showed high activity against S. aureus and MRSA with the lowest minimum inhibitory concentration (MIC) of 0.5 μg ml−1. At concentration of four times its MIC, AMA11CE destroyed MRSA cells as analysed by the scanning electron microscopy. In addition, AMA11CE, ethyl acetate extract from the culture broth of AMA12 (AMA12BE), AMA12CE and AMA21CE reduced violacein production in Chromobacterium violaceum. Furthermore, at concentrations lower than 10 μg ml−1, all five extracts inhibited biofilm formation by S. epidermidis ATCC35984. The chemical analysis of the most active fraction from AMA11CE by GC-MS revealed the presence of 3-nitro-1,2-benzenedicarboxylic acid, hexadecanoic acid, quinoxaline-2-carboxamide and pentadecanoic acid. The 16S rDNA sequencing analysis revealed that these three potential isolates belonged to the genus Streptomyces. The results revealed that the actinomycetes from mangrove environment would be a good source of bioactive metabolites against pathogenic bacteria.

Daya Dukung Ekosistem Mangrove Terhadap Hasil Tangkap Nelayan di Taman Hutan Raya Ngurah Rai, Bali

Mangrove ecosystem is a complex ecosystem. The sustainability of fish resources is highly dependent on the sustainability of the mangrove ecosystem. The purpose of this research is to know the mangrove density, fish catching from fisherman in mangrove area and relationship of mangrove vegetation and the quality of the waters with the fish catching in the mangrove. Data collections include mangrove condition, fish catching, and water environment parameter. Research conducted in the mangrove area Mina Werdhi Batulumbang (TP I) and Simbar Segara (TP II). The results of this study found 5 species of mangrove. The density values of species at research site I ranged between 0.02 ind / m2 - 0.08 ind / m2. While the density value of species in this research site II ranged between 0.01 ind / m2 - 0.07 ind / m2. Rhizophora mucronata type has the highest density. Fish catching is the largest average in research place I, that is 1.42 kg /day /fisherman with mangrove area 2,397 Ha and the research of site II shows that the fish production of fisherman catches of 0,8 kg / day / fisherman with mangrove area 1,986 Ha. There is a positive relationship between the density and area of mangrove with the number of fish catching, where the fish catching will increase when the mangrove area also increases and there is a strong relationship between the catch and dissolved oxygen.

Epibiotic communities (microalgae and meiofauna) on the pneumatophores of Avicennia officinalis (L.)

In a mangrove environment, several groups of organisms are symbiotically associated with pneumatophores (aerial roots). But whether these organisms are exclusively found in this habitat (uniqueness) or accidentally settled here from water or sedimentary habitat, is not clearly understood. This hampers our understanding of their functional ecology. Hence the present study aimed to characterise the epibiotic microalga and meiofauna from the pneumatophores of mangrove Avicennia officinalis. To determine the habitat influence, these communities were also compared with those found in water and sedimentary habitat. Four estuarine mangrove sites represented by brackish water (salinity varying from 5 to 12) and located at different spatial scales (5–50 km distance) were chosen to determine whether these communities are consistent or vary with sites. Overall, the microalgal community was found to vary both among the habitats as well as sites. In the pneumatophore habitat, several tychoplanktons such as Coscinodiscus, Thalassionema, Cyclotella, Fragilariopsis, and Biddulphia were observed instead of benthic ones. These diatoms are planktonic genera and might have settled on pneumatophores from the water column. The observed variability in the microalgal composition among the sites is possibly due to predatory interactions or the dominance of particular species of macroalga that govern the diatom community. On the other hand, among the meiofaunal community, diptera, halacarida, tanaidacea, and foraminifera were mainly found in the pneumatophore habitat than in the sediment. Because pneumatophores either provide refugee to meiofauna against predators or are saturated with oxygen that meiofauna can utilize for respiration. Pneumatophores were also found to harbour several rare (abundance <1%) epibionts, the ecological importance of which is discussed in this paper.

A Unique Coral Community in the Mangroves of Hurricane Hole, St. John, US Virgin Islands

Corals do not typically thrive in mangrove environments. However, corals are growing on and near the prop roots of red mangrove trees in Hurricane Hole, an area within the Virgin Islands Coral Reef National Monument under the protection of the US National Park Service in St. John, US Virgin Islands. This review summarizes current knowledge of the remarkable biodiversity of this area. Over 30 scleractinian coral species, about the same number as documented to date from nearby coral reefs, grow here. No other mangrove ecosystems in the Caribbean are known to have so many coral species. This area may be a refuge from changing climate, as these corals weathered the severe thermal stress and subsequent disease outbreak that caused major coral loss on the island’s coral reefs in 2005 and 2006. Shading by the red mangrove trees reduces the stress that leads to coral bleaching. Seawater temperatures in these mangroves are more variable than those on the reefs, and some studies have shown that this variability results in corals with a greater resistance to higher temperatures. The diversity of sponges and fish is also high, and a new genus of serpulid worm was recently described. Continuing research may lead to the discovery of more new species.