Mangrove Zone Research Articles

Mercury methylation and sulfate reduction rates in mangrove sediments, Rio de Janeiro, Brazil: The role of different microorganism consortia

Recent studies have shown Hg methylation in mangrove sediments, however, little is known about the different microorganism consortia involved. We investigated the participation of prokaryotes in general, iron-reducing bacteria-IRB, sulfate-reducing bacteria-SRB, methanogens and fungi in Hg methylation and sulfate reduction rates (SRR) in mangrove sediments using iron amendments for IRB and specific inhibitors for the other microorganisms. Sediment samples were collected from two mangrove zones, tidal flat and mangrove forest (named root sediments). Samples were incubated with 203Hg or 35SO42− and Me203Hg/35Sulfur were measured by liquid scintillation. Methylmercury (MeHg) formation was significantly reduced when SRB (87.7%), prokaryotes (76%) and methanogens (36.5%) were inhibited in root sediments, but only SRB (51.6%) and prokaryotes (57.3%) in tidal flat. However, in the tidal flat, inhibition of methanogens doubled Hg methylation (104.5%). All inhibitors (except fungicide) significantly reduced SRR in both zones. In iron amended tidal flat samples, Hg methylation increased 56.5% at 100 μg g−1 and decreased at 500 and 1000 μg g−1 (57.8 and 82%). In the roots region, however, MeHg formation gradually decreased in response to Fe amendments from 100 μg g−1 (37.7%) to 1000 μg g−1 (93%). SRR decreased in all iron amendments. This first simultaneous evaluation of Hg methylation and sulfate-reduction and of the effect of iron and inhibitors on both processes suggest that SRB are important Hg methylators in mangrove sediments. However, it also suggests that SRB activity could not explain all MeHg formation. This implies the direct or indirect participation of other microorganisms such as IRB and methanogens and a complex relationship among these groups.

Per-pixel and sub-pixel classifications of high-resolution satellite data for mangrove species mapping

High spatial resolution sensors such as IKONOS and QuickBird, are expected to classify mangrove species more accurately than coarse spatial resolution satellite images. Conventional per-pixel classification techniques could not improve the classification accuracy when such high-resolution images are applied. Such failure has encouraged the invention of more sophisticated and deterministic techniques i.e. subpixel classifications. In this study, the mangrove forest at Sungai Belungkor, Johor, Malaysia was classified using IKONOS data. Two classification approaches were applied, namely per-pixel and sub-pixel techniques. The conventional per-pixel classifiers used in this study were Maximum Likelihood (ML), Minimum Distance to Mean (MDM) and Contextual Logical Channel (CLC) while the Linear Mixture Model (LMM) was selected as the sub-pixel classification approach. The classification results revealed that the CLC classification with a contrast texture measure at window size 21 x 21 yielded the highest accuracy (82%) in comparison to the ML (68%) or MDM (64%). The spatial distribution of the classified mangrove species and classes coincided with the common mangrove zones in Malaysia. For the results of the LMM, the fraction of pixels measured from the satellite imagery and observed in the field gave a good correlation with an R2 value of 0.83 for Bakau minyak, a moderate correlation with an R2 of approximately 0.71 for Bakau kurap and an R2 of 0.75 for the ‘Others’ type of mangrove species. An error image was also created to compare the best fitting spectrum produced by the inversion of the LMM with the original observed spectrum, where the maximum RMS error was only 5%.

Characterization of mangrove species using ALOS-2 PALSAR in Hai Phong city, Vietnam

Hai Phong city is located in the Northern coast of Vietnam where the mangroves are distributed between zone I and zone II among the four mangrove zones in Vietnam. This city is vulnerable to rising sea levels associated with climate change and tropical cyclones, which are forecasted to become more severe due to the impact of climate change. In the past, mangrove forests in this city have decreased markedly because of over expansion of shrimp farming. Thus, identification of mangrove forests is important to monitor and support mangrove conservation and management in the coastal zone. The objectives of this research were to identify the locations of mangrove and characterize mangrove species in Hai Phong using HH and HV backscatters of the Advanced Land Observing Satellite 2 (ALOS-2) with enhanced Phased Array L-band Synthetic Aperture Radar (PALSAR). Image segmentation was used to identify the locations of mangrove forests. Moreover, Geographic Information System (GIS) was applied to update current status of mangrove species in 2015. The results showed that the means of HH and HV backscatter coefficients of K. obovata are lower than S. caseolaris. K. obovata has HH value around -13.9 dB until -10.3 dB and HV value around -20.6 dB until -16.2 dB. Higher HH values between about -14.9 dB and -6.8 dB and HV values between roughly -20.6 dB and -14.3 dB have observed by S. caseolaris. The total area of mangrove forest in Hai Phong in the year 2015 was around 4084 hectares, of which S. caseolaris occupied over 68% and mixed mangrove species was approximately 25.6%. This research indicates the potential for the use of L-band ALOS-2 PALSAR in characterizing mangrove forest species in the coastal zone.

Meiofauna distribution in a mangrove forest exposed to shrimp farm effluents (New Caledonia)

Meiofauna abundance, biomass and individual size were studied in mangrove sediments subjected to shrimp farm effluents in New Caledonia. Two strategies were developed: i) meiofauna examination during the active (AP) and the non-active (NAP) periods of the farm in five mangrove stands characteristics of the mangrove zonation along this coastline, ii) meiofauna examination every two months during one year in the stand the closest to the pond (i.e. Avicennia marina). Thirteen taxonomic groups of meiofauna were identified, with nematodes and copepods being the most abundant ones. Meiofauna abundance and biomass increased from the land side to the sea side of the mangrove probably as a result of the increased length of tidal immersion. Abundance of total meiofauna was not significantly different before and after the rearing period. However, the effluent-receiving mangrove presented twice the meiofauna abundance and biomass than the control one. Among rare taxa, mites appeared extremely sensitive to this perturbation.

Strategies of Bioremediation for the Degradation of Petroleum Hydrocarbons in the Presence of Metals in Mangrove Simulated

Contamination by oil spills in coastal ecosystems, especially in mangrove zones, has been common in countries with oil industry. The aim of this study was, therefore, to evaluate the efficiency of application of the two models developed for pilot‐scale remediation, intrinsic bioremediation (indigenous microorganisms), and phytoremediation (Avicennia schaueriana). The degradation of hydrocarbons was determined by gas chromatography (GS) with flame ionization detector. The metals Al, Fe, Pb, Cr, Cu, Zn, and Ni were determined by flame atomic absorption spectrometry in the mangrove simulated with sediment of Todos os Santos Bay, Brazil. These models also monitor other biogeochemical parameters (nitrogen, phosphorus, total organic carbon, pH, redox potentioal, dissolved oxygen, salinity, temperature, bacterial density). The integrated assessment of data showed that both techniques were effective in degrading organic compounds from oil but that phytoremediation is the most efficient (89% removal). The intrinsic bioremediation model has no direct correlation with metal concentrations, but a positive correlation with Al and Ni was found in the hydrocarbon removal by phytoremediation.Avicennia schauerianarepresents efficiency in phytoextraction and phytostimulation. The results suggest that the phytoremediation model, through its various mechanisms, may become a technique for the removal of petroleum hydrocarbons in the presence of metals in mangrove ecosystems near industrial areas.

Legacy impacts of acid sulfate soil runoff on mangrove sediments: Reactive iron accumulation, altered sulfur cycling and trace metal enrichment

The off-site impacts of iron-rich, acidic runoff from drained acid sulfate soils (ASS) on the geochemistry of estuarine sediments are relatively poorly constrained. In this study, we examine the geochemistry of intertidal zone mangrove sediments and porewaters from an estuarine tributary that received ~15–20years of acute ASS drainage, compared to adjacent control sites. Mixing of acidic, iron-rich ASS drainage waters with circumneutral pH estuarine waters drove precipitation of Fe(III) floc and has led to significant, localized accumulation of reactive-Fe species (FeR; Σ1M HCl and citrate-buffered dithionite extracts; up to 4200μmolg−1) as well as significantly elevated porewater Fe2+ (>1000μM) in ASS impacted sediments. X-ray diffraction indicates that goethite, lepidocrocite and ferrihydrite are important Fe(III) minerals in surficial sediments at ASS impacted sites. The abundant FeR is shifting the equilibrium of reduced inorganic sulfur (RIS) mineral-formation pathways towards accumulation of S(0) and acid volatile sulfide (AVS) species and is buffering porewater S(-II) to low concentrations. In contrast, RIS speciation at the control sites is dominated by pyrite (SCR) and porewater S(-II) is present. Some porewater metals (i.e. Al, Mn, Cu, Cr) are significantly elevated at sites proximal to the source of ASS drainage compared to control sites. Abundant FeR also provides a substrate for sorption and accumulation of metals and correspondingly there is significant relative enrichment of reactive metal fractions (1M HCl extractable) in sediments at the ASS impacted sites, with Al≈Mn≈U>Cu>Cr>Ni. This study demonstrates that ASS drainage, which causes accumulation of reactive Fe in mangrove environments, can substantially influence sediment biogeochemistry by altering reduced inorganic sulfur cycling and enhancing the availability of some trace metals.

Characterization of Archaeological Sediments Using Fourier Transform Infrared (FT-IR) and Portable X-ray Fluorescence (pXRF): An Application to Formative Period Pyro-Industrial Sites in Pacific Coastal Southern Chiapas, Mexico.

Archaeological sediments from mounds within the mangrove zone of far-southern Pacific coastal Chiapas, Mexico, are characterized in order to test the hypothesis that specialized pyro-technological activities of the region's prehistoric inhabitants (salt and ceramic production) created the accumulations visible today. Fourier transform infrared spectroscopy (FT-IR) is used to characterize sediment mineralogy, while portable X-ray fluorescence (pXRF) is used to determine elemental concentrations. Elemental characterization of natural sediments by both instrumental neutron activation analysis (INAA) and pXRF also contribute to understanding of processes that created the archaeological deposits. Radiocarbon dates combined with typological analysis of ceramics indicate that pyro-industrial activity in the mangrove zone peaked during the Late Formative and Terminal Formative periods, when population and monumental activity on the coastal plain and piedmont were also at their peaks.

DISTRIBUTION AND DEPOSITIONAL HISTORY OF SOME PRE-LAGOONAL HOLOCENE SEDIMENTS IN THE CIÉNAGA GRANDE DE SANTA MARTA, COLOMBIA

An investigation of the pre-lagoonal Holocene sediments from beneath the Ciénaga Grande de Santa Marta (Colombia) was undertaken for the purpose of better understanding the paleogeographical and paleoecological conditions of this region before the formation of the lagoon proper. Core and grab samples were collected from the lagoon for stratigraphic observation and analysis in the laboratory. Beneath the recent lagoonal sediments a deposit of peat with intercalated sand and clay was discovered. Its surface lies at a depth of about 2 m below the hydrographic zero level of the lagoon. Three peat samples, obtained from the upper portion of this deposit, were subjected to micropetrographic and pollen analyses. These analyses revealed that, prior to marine inundation, this region was a coastal marsh-swamp complex similar to the Everglades-mangrove region in southern Florida (U. S. A.). Sample "f" , taken closest to the present sea, represents a red mangrove (Rhizophora mangle) dominated zone, which was relatively exposed to tides and waves, so that the energy was great enough to sweep the sediment surface clean of litter. This implies that the Isla de Salamanca, an almost continuous beach barrier between the present-day lagoon and the Caribbean Sea, must not have been as prominent a barrier as it is today, but that a larger inlet existed near the site of formation of this particular peat sample. The next most inland sample " g" represents a mixed mangrove zone which was somewhat less exposed to current scour and which was presumably situated behind and protected by the former zone. The third sample "h" , taken the furthest inland, represents ponded conditions within a slightly brackish to fresh water marsh dominated by leatherleaf fern (Acrostichum aureum) and sedges. This relatively stable zonation of vegetational environments from marine mangrove in the north to fresh water marshes in the south briefly before the termination of peat formation suggests that the transgression which formed the lagoon was so rapid that marine floral communities had no time to migrate inland and cover more of the submerging swamp surface. This assumption is supported by C14 dates which show that the uppermost peat layers were formed approximately 2 400 years ago in the north and 1 900 years ago in the south, so that the transgression over the swamp should not have taken longer than 500 years. It is recognized, however, that the small number of analyzed samples does not permit far-reaching conclusions. Four different species of molluscs encountered in peat and clay samples from a few locations in the northern and southern Ciénaga are typical brackish water species. This is evidence for the early existence of small low-salinity lagoons and creeks within the marsh-swamp setting. Some additional stratigraphic information was obtained by probing with a steel rod capable of penetrating the recent lagoonal sediments as well as the peat. With reference to the water level a shorter depth down to a "firm substrate" (dense sand or indurated clay) was encountered in the southern part of the lagoon than in the rest of the lagoon. This "substrate high" probably represents a submerged lobe of a former subdelta of the Magdalena River. The common association of peat with layers of sand and clay in this region also points to a nearby source for clastics. In general the discharge of sediments into the swamp was sporadic, with long periods during which the rate of clastic sedimentation was low enough to allow the accumulation of relatively pure peats.

Molluscan Fauna in Bang Taboon Mangrove Estuary, Inner Gulf of Thailand: Implications for conservation and sustainable use of coastal resources

Molluscan fauna, dealt with diversity and abundance of gastropods and bivalves in Bang Taboon mangrove estuary, Inner Gulf of Thailand was investigated seasonally. Totally 3,337 individuals, representing 18 species (6 bivalves and 12 gastropods) with two dominant species, Assiminea brevicula and Tegillarca granosa . The mean density of overall molluscs was 11.79±0.47 n/m 2 , recorded in September. The highest value of diversity was 0.78±0.53, recorded in March. The most species-rich and individuals were recorded in the large mudflat within intertidal mangrove zone and formed a distinct community structure in the vegetated area at 15 cm depth. Results from the Analysis of the Similarity (ANOSIM) showed a clearly significant difference of species diversity and abundance at different areas, depths and seasons (P = 0.001). Although Bang Taboon estuary is impacted by human activities, the habitat remains an important nursery ground for numerous molluscs including many commercial species. The findings of this study can be taken as a base data that would help maximizing mangrove and fisheries resources conservation and utilization in a sustainable way in Bang Taboon estuary and adjacent areas in the inner Gulf of Thailand.

Assemblages of phytoplankton diversity in different zonation of Muthupet mangroves

The aim of this paper is to determine the seasonal successions, diversity and assemblages of phytoplankton population in different zones of Muthupet mangroves. The phytoplankton characteristics were studied at four different mangroves zones during 12 months of sampling period with monthly intervals. Species diversity, richness and evenness were calculated. Altogether, 72 species of phytoplankton were identified. The species belonging to four groups namely diatoms, dinoflagellates, blue greens and greens were recorded. Among these groups, diatom showed the highest contribution of the total abundance (Up to 70% in the different zone of Muthupet mangroves) and found to be more dominant in marine and Avicennia zone whereas blue greens and greens were found to be meagre in all the zones.

Distribution, sources and biogeochemistry of organic matter in a mangrove dominated estuarine system (Indian Sundarbans) during the pre-monsoon

The sources and distribution of dissolved organic carbon (DOC), particulate organic carbon (POC) and dissolved inorganic carbon (DIC) in the Indian Sundarbans mangrove and Hooghly estuarine system were examined during the pre-monsoon (summer) 2014. DOC is the dominant form of organic matter (OM) in the studied estuarine waters and represents a mixture of mangrove and riverine sources. Microbial degradation of land derived OM results in a high pCO2 in the Hooghly estuarine waters while enrichment in δ13C-DIC ascribes to CO2 uptake by phytoplankton in the Sundarbans water. Higher δ15N in the particulate organic nitrogen (PON) of the mangrove and marine zone could be associated with enhanced phytoplankton production sustained by nitrate from mangrove derived OM decomposition and/or nitrate imported from the Bay of Bengal. Low organic carbon contents and elemental ratios (TN/TOC) indicate an intense mineralization and transformation of OM in the sediments, resulting insignificantly different OM compositions compared to those of the three major sources: land derived OM, mangrove leaf litter (Avicennia marina) and in situ phytoplankton production.

Carcinofauna bêntica estuarina de dois manguezais da costa amazônica maranhense, Brasil

RESUMO Este estudo teve por objetivo caracterizar a diversidade carcinológica de dois manguezais (igarapés Buenos Aires e Tronco) da Baía de São Marcos, na costa amazônica maranhense, Brasil. Foram realizadas quatro coletas trimestrais entre setembro de 2011 a junho de 2012. Em cada coleta foram analisados três pontos por área (zona 1, zona 2 e zona 3), totalizando 24 amostras. O material biológico foi coletado por meio de arrastos com rede do tipo puçá, catação manual e técnica de braceamento. Paralelamente à coleta do material biológico, foram verificados a salinidade, temperatura e oxigênio dissolvido de cada área analisada. Para avaliar a similaridade de agrupamento entre as zonas dos manguezais foi aplicada a análise de cluster e consecutiva elaboração de dendrogramas. Foi coletado um total de 873 indivíduos, representando nove famílias e 21 espécies, das quais Ocypodidae e Penaeidae foram as mais abundantes. Em relação à distribuição espacial, percebe-se que Clibanarius vittatus (Bosc, 1802), Clibanarius tricolor (Gibbes, 1850), Clibanarius foresti Holthuis, 1959 e Uca maracoani (Latreille, 1802) se restringiram à primeira zona dos dois manguezais, enquanto outras dez espécies foram observadas por todo o manguezal, o que pode estar intimamente relacionado ao seu hábito de vida. De um modo geral, o igarapé Buenos Aires apresentou maior número de espécies em relação ao igarapé Tronco, no entanto, existe grande similaridade faunística de crustáceos decápodes entre as duas áreas amostradas.

Gastropods shell utilization among hermit crabs targeted by bait fishers along a tropical mangrove fringed creek, Mida, Kenya

Mangrove gastropods and hermit crabs are frequently harvested for use as bait by artisanal trap and hook fishers, along the Kenyan coastline and elsewhere. In addition to mangrove degradation, the harvesting of shelled invertebrates, can alter shell availability and hence survival of these interdependent fauna. This study compares shell morphometric characteristics such as shell availability, adequacy and bait yield, among sites with different patterns of bait harvesting and other human disturbances. Shell morphometrics are also related to mangrove forest stand characteristics such as forest complexity, dominance, cutting intensity and sapling regeneration. Results indicate that the sampling regime, hermit crab taxa and mangrove zone influence morphometric characters of the gastropod and hermit crab. Significantly higher (P < 0.001) shell availability, adequacy and bait yield of the predominant hermit crab, Clibanarius danai, are recorded at upper and mid forested zones of sites with robust forest. This was attributed to shell selectivity of the crab, coupled with constancy of the environment at closed canopy sites. Apparently, forest structure is an important determinant of shell utilization patterns compared to prevailing bait harvesting activity. Protection of robust upper mangrove forest zones may therefore enhance sustainability of shelled bait harvesting and consequently the livelihoods support emanating from bait fishery.

Differences in root aeration, iron plaque formation and waterlogging tolerance in six mangroves along a continues tidal gradient.

Mangrove is a special coastal forest along tropical and subtropical intertidal shores. However, how mangroves adapt to tidal flooding and the mechanisms involved in mangrove zonation are still poorly understood. In this study, a pot trial with different tide treatments was conducted to investigate the differences in root anatomy, porosity, radial oxygen loss, iron plaque formation and waterlogging tolerance among six mangroves along a continuous tidal gradient. The index of waterlogging tolerance illustrated that Sonneratia apetala possessed the highest index, followed by Aeguceras corniculatum/Kandelia, Rhizophora stylosa, Heritiera littorlis and Thespesia populnea. Waterlogging tolerances of the mangroves were found to be positively correlated with their root porosity, radial oxygen loss and iron plaque formation. Waterlogging-sensitive species such as landward semi-mangroves exhibited small root porosity and ROL, while waterlogging-tolerant species such as seaward pioneer and rhizophoraceous mangroves exhibited extensive porosity, ROL and iron plaque formation. Nevertheless, grater root porosity and iron plaque formation were detected in permanent waterlogged plants when compared to drained plants. In conclusion, The present study proposes a structural adaptive strategy to tidal flooding in mangroves, such that the mangroves with higher root porosity, ROL and iron plaque appeared to exhibit higher waterlogging tolerance and adaptability in anaerobic foreshores.

Object-Based Approach for Multi-Scale Mangrove Composition Mapping Using Multi-Resolution Image Datasets

Providing accurate maps of mangroves, where the spatial scales of the mapped features correspond to the ecological structures and processes, as opposed to pixel sizes and mapping approaches, is a major challenge for remote sensing. This study developed and evaluated an object-based approach to understand what types of mangrove information can be mapped using different image datasets (Landsat TM, ALOS AVNIR-2, WorldView-2, and LiDAR). We compared and contrasted the ability of these images to map five levels of mangrove features, including vegetation boundary, mangrove stands, mangrove zonations, individual tree crowns, and species communities. We used the Moreton Bay site in Australia as the primary site to develop the classification rule sets and Karimunjawa Island in Indonesia to test the applicability of the rule sets. The results demonstrated the effectiveness of a conceptual hierarchical model for mapping specific mangrove features at discrete spatial scales. However, the rule sets developed in this study require modification to map similar mangrove features at different locations or when using image data acquired by different sensors. Across the hierarchical levels, smaller object sizes (i.e., tree crowns) required more complex classification rule sets. Incorporation of contextual information (e.g., distance and elevation) increased the overall mapping accuracy at the mangrove stand level (from 85% to 94%) and mangrove zonation level (from 53% to 59%). We found that higher image spatial resolution, larger object size, and fewer land-cover classes result in higher mapping accuracies. This study highlights the potential of selected images and mapping techniques to map mangrove features, and provides guidance for how to do this effectively through multi-scale mangrove composition mapping.

Morphologic variations of periwinkle and profiles of periwinkle marketers and harvesters in two states in the Niger delta area of Nigeria

Periwinkles are invertebrates rich in protein and omega-3 fatty acids. These make them relished delicacies. Three hundred and fifteen (315) individual periwinkles were hand-picked from mangrove swamp river banks and intertidal zones of Twon-Brass in Bayelsa State and Abonnema town of Rivers State. Shell length and the weight of both the meat and shell were taken with Veneer caliper and a sensitive electronic scale balance respectively. Information on the economics of production was gathered from market women and harvesters through the use of structured questionnaires. The present study indentified possible phenotypic differences among periwinkle harvested in Bayelsa and Rivers States base on shell length and meat weight differences. Periwinkle harvested in Rivers is bigger and heavier than those harvested in Bayelsa State. Prediction of meat and total weight of from shell length was done using regression analysis. The study also identified the involvement of the different age groups that form the work-force in the States; showing that there are more young adults and teenagers in the business of harvesting and sales than aged people. There are more men involved in the business than women. There is a decline in size, quantity and availability of periwinkle presently than in the past, a factor that could be attributed to over-harvesting.Key Words: Bayelsa, Morphology, Niger Delta, Periwinkle, Rivers.

Forestación de isletas de dragado utilizando dos especies de mangles, en una laguna costera del Golfo de California, México

El propósito del presente estudio fue generar información en torno a la posibilidad de estabilizar isletas de dragado mediante la plantación de halófitas, particularmente con la creación de nuevas áreas de manglar. Para esto, fue construido un vivero para producir plantas de Avicennia germinans y Rhizophora mangle , a la vez que se obtuvieron individuos del medio natural para ambas especies. Para su plantación se consideró el intervalo de mareas, áreas de baja energía, salinidad, zonación de cada especie y un diseño experimental de bloques completos al azar. Los resultados indicaron una mayor supervivencia y crecimiento de las plantas de vivero que las extraídas del medio natural. La supervivencia de plantas de A. germinans (78% con contenedor, 72% sin contenedor, 34% medio natural) fue mayor que la de R. mangle (43% con contenedor, 34% sin contenedor, 2% medio natural). De igual manera, el crecimiento en altura de las plantas de A. germinans , tanto de las producidas en vivero (3.2 cm mes-1), como las extraídas del medio natural (1.5 cm mes-1), fue mayor que las de R. mangle (producidas en vivero: 1.4 cm mes-1; extraídas del medio natural: 0.8 cm mes-1). No se presentó colonización natural durante el periodo de estudio, por lo que son recomendables las plantas de vivero para iniciar la forestación de isletas artificiales, considerando las mareas, la zonación natural local, áreas de baja energía y sobre todo, el hidroperiodo.

Impact of Topography and Tidal Height on ALOS PALSAR Polarimetric Measurements to Estimate Aboveground Biomass of Mangrove Forest in Indonesia

This study is focused on investigating the impact of topography and tidal height on ALOS PALSAR polarimetric measurements on HH and HV for estimating aboveground biomass (AGB) of mangrove forest in Indonesia. We used multitemporal ALOS PALSAR polarimetric measurement that covered mangrove zone in Banyuasin, Cilacap, and Teluk Bintuni and also collected tidal height data within the same acquisition date with multitemporal ALOS PALSAR polarimetric measurement. We analyzed the distribution of flooding and nonflooding areas based on tidal height and SRTM topography data, created three profiles as region of interest (ROI), and got characteristics of backscatter value on HH and HV with different tidal height. The result of this study showed backscatter of the open mangrove zones during high tide with HH value less than −20 dB and HV value less than −25 dB whereas during low tide it showed an HH value around −20 to −10 dB and HV value around −25 to −10 dB. Backscatter of the middle mangrove zones at Cilacap, with low and flat topography, showed a deviation of backscatter on HV value of 1.6 dB. Finally, the average AGB of mangrove forest in Indonesia was estimated based on ALOS PALSAR polarimetric measurements.

Effects of Mangrove Zonation and the Physicochemical Parameters of Soil on the Distribution of Macrobenthic Fauna in Kadolkele Mangrove Forest, a Tropical Mangrove Forest in Sri Lanka

The ecology of the macrobenthic fauna of the mangrove forests has received little attention compared to the mangrove flora. The present study was aimed at filling this information gap and investigated if the diversity and distribution of macrobenthic fauna at Kadolkele mangrove forest, a pristine mangrove forest situated at the Negombo estuary in Sri Lanka, are governed by the mangrove zonation and variation of physicochemical parameters of the mangrove soil. Since the aerial photographs identified three distinct mangrove zones at Kadolkele, namely, Rhizophora, Avicennia, and Lumnitzera zones, fauna were sampled and physicochemical parameters of the soil were measured in belt transects that were established at each mangrove zone. Data were collected and analyzed using appropriate field sampling techniques and statistical methods, respectively. Results revealed that the physicochemical parameters in soil varied between the three mangrove zones and that the distribution of benthic fauna followed the mangrove zonation. Further, the diversity measures of epifauna were found to be higher than those of the infauna of this tropical estuary.

THE USE OF MANGROVES IN COASTAL PROTECTION

The objective of this research is to obtain generic relations between attenuated wave heights and various vegetation and topographical scenarios. Subsequently, it is aimed to find out what is the actual cost profit of a dike construction behind a mangrove zone comparing to the case when mangroves are absent. The graphs and formulas developed in this research may serve as a first approximation during feasibility studies or conceptual designs of a coastal dike incorporating mangrove vegetation. They allow calculating the design wave height attenuated by site specific or planned for restoration mangrove forests, for different design met-ocean conditions. Calculated wave reduction coefficients can be later on translated to the cost savings of a coastal dike raised behind the mangrove forests.