Modelling of Geochemical Processes in Mangrove Ecosystem

The mangrove ecosystem is one of the earth’s most endangered ecosystems. In this study, geochemical features of three mangrove ecosystems, Mangalavanam, Vypeen and Nettoor were compared. Water, sediment and core samples were collected from these stations for a period of one year. Nutrients, organic compounds orgnic carbon and hydrographical parameters of the samples were estimated. The present study revealed higher concentration of carbon in the surface sediments. The major temporary or ultimate sink for various pollutants in estuaries is the sedimentary reservoir, including intertidal areas. In the present study, higher values for dissolved nutrients, POC and carbohydrates were observed during low tide.

Sorptional Behaviour of Metals on the Sediments and Humic acid of Mangrove Ecosystem

Humic substances are complex polymeric structures.No other polymers with such a wide range of properties are so widely distributed in nature.But still their moleculer structures are unknown. A structural knowledge is essential in determining their reactivity with metals.In the present work structural elucidation of humic acids from three different mangrove ecosystems of Cochin area is done with the available data from functional group analysis and various spectroscopic methods.13C NMR spectra of the solid samples with CPMAS,IR and SEM are very promising in revealing the complex structures of these polymeric substances.Sorptional studies on the sediment and humic acid of mangrove ecosystem reveals that the major portion of the organic matter is not extractable with Sodium hydroxide and humic acid only a small portion of the total organic matter. Humic acid is a good complexing agent and scavenger. Due to the nonextractable nature of the organic matter present with the sediment left after alkali extraction it is a better scavenger.

Microalgal vegetation in the selected Mangrove Ecosystem of Kerala.

Department of Marine Biology, Cochin University of Science & Technology

Microbial production of antibiotics from mangrove ecosystem

The present study on "Microbial production of antibiotics from mangrove ecosystem” was carried out for a period of one year in four selected Stations, Mangalavana, Narakkal, Puthuvyppu and light house area of Puthuvyppu (9°55' — 10°10'N and 76°10‘ - 76°20'E) from January to December 1991. Though much emphasis has been given to occurrence and distribution of actinomycetes, an attempt was also made to understand the distribution patterns of other micro flora in the sediments. Data on physico-chemical parameters were also collected to find out their relationship if any with the microflora. The principle interest of the present investigation is to determineseasonal variations of antagonistic actinomycetes in selected mangrove ecosystem. The microbial interrelationship in mangrove sediments was found out by constructing the ratio between bacteria and actinomycetes, bacteria and fungi, fungi and actinomycetes. In addition temperature, pH, salinity, dissolved oxygen and organic carbon were determined seasonally and their possible relationship was statistically analyzed and the results are presented. Isolated actinomycetes were subjected to cross streak assay to know their nature of antibiotic activity against test fish pathogens and crude antibiotics were extracted from selected isolates and their inhibitory activity is studied and the results are discussed.

Studies on some aspects of mangrove ecosystem in a tropical estuary"

The situation in the backwaters of Kerala, which reportedly had about 70,000 ha of mangroves, is unique in the sense that there has been a total conversion to other uses such as paddy cultivation, coconut plantation, aquaculture, harbour development and urban development In order to save and restore what is left over national and international organisations are mounting pressure on scientists and policy makers to work out ways and means conserving and managing the mangrove ecosystems. In this context, it has been observed in recent years that mangrove vegetation has remained intact in isolated pockets of undisturbed areas in the Cochin estuarine system and also that there is resurgence of mangroves in areas of accretion and silting. The candidate took up the present study with a view to make an inventory of the existing mangrove locations, the areas of resurgence, species composition, zonation and other ecological parameters to understand their dynamism and to suggest a mangement plan for this important coastal ecosystem

Fiji mapped mangrove ecosystem service rankings in GeoJSON format

Incorporating the values of the services that ecosystems provide into decision making is becoming increasingly common in nature conservation and resource management policies, both locally and globally. Yet with limited funds for conservation of threatened species and ecosystems there is a desire to identify priority areas where investment efficiently conserves multiple ecosystem services. We mapped four mangrove ecosystems services (coastal protection, fisheries, biodiversity, and carbon storage) across Fiji. Using a cost-effectiveness analysis, we prioritised mangrove areas for each service, where the effectiveness was a function of the benefits provided to the local communities, and the costs were associated with restricting specific uses of mangroves. We demonstrate that, although priority mangrove areas (top 20%) for each service can be managed at relatively low opportunity costs (ranging from 4.5 to 11.3% of overall opportunity costs), prioritising for a single service yields relatively low co-benefits due to limited geographical overlap with priority areas for other services. None-the-less, prioritisation of mangrove areas provides greater overlap of benefits than if sites were selected randomly for most ecosystem services. We discuss deficiencies in the mapping of ecosystems services in data poor regions and how this may impact upon the equity of managing mangroves for particular services across the urban-rural divide in developing countries. Finally we discuss how our maps may aid decision-makers to direct funding for mangrove management from various sources to localities that best meet funding objectives, as well as how this knowledge can aid in creating a national mangrove zoning scheme.

Seoimentology And Geochemistiiy Of Some Selected Mangrove Ecosystems Of Kerala, Southwest Coast Of India

As a result of the issues of care and conservation and sustainable utilisation, the proper management of mangrove forests have become more pressing than ever. Much recent ecological and toxicological debate has been centered around the question of validity of making predictions about the future of mangrove ecosystemas a result of the newly evolved environmental policy. Though muchinformation exist on the biodiversity, floristic composition and characteristics, geographical distribution and uses of mangroves, systematic documentation of the various sedimentological and geochemical phenomena in relation to the mangrove flora are scarce. Hazardous, persistent, man-made chemicals and waste produces are entering the mangrove ecosystem at from the adjacent watersheds which strengthened alarming rates the indispensible need for further researches on the environmental behaviours, fate and the effect of such products. Studies on the effect of heavy metals, pesticides and the other toxic signals through bioassay and toxicity tests on mangrove species as well as in sediments definitely will furnish ample clues to establish the actual operative mechanisms of these environments. A thorough review of literature made in this angle reveals that some attempts have already been initiated the world over the record the physico-chemical characteristics of major abiotic components such as sediments and water of many mangrove ecosystem, however, adequate information is lacking in the Indian Environmental Science scenario. The present investigation is an attempt to record the sedimentological, mineralogical and geochemical characteristics of sediments as well as the heavy metal enrichment in the various species ofmangrove flora of three important mangrove ecosystems of Kerala, located at Veli (SouthKerala), Kochi (Central Kerala) and Kannur (North Kerala). The results of the above investigation have been analysed statistically, discussed based on the available literature and presented in this thesis under seven chapters

Microbial populations and activities of mangrove, restinga and Atlantic forest soils from Cardoso Island, Brazil

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Cyanobacterial diversity in the phyllosphere of a mangrove forest

The cyanobacterial community colonizing phyllosphere in a well-preserved Brazilian mangrove ecosystem was assessed using cultivation-independent molecular approaches. Leaves of trees that occupy this environment (Rhizophora mangle, Avicennia schaueriana and Laguncularia racemosa) were collected along a transect beginning at the margin of the bay and extending upland. The results demonstrated that the phyllosphere of R.similar to mangle and L.similar to racemosa harbor similar assemblages of cyanobacteria at each point along the transect. A.similar to schaueriana, found only in the coastal portions of the transect, was colonized by assemblages with lower richness than the other trees. However, the results indicated that spatial location was a stronger driver of cyanobacterial community composition than plant species. Distinct cyanobacterial communities were observed at each location along the coast-to-upland transect. Clone library analysis allowed identification of 19 genera of cyanobacteria and demonstrated the presence of several uncultivated taxa. A predominance of sequences affiliated with the orders Nostocales and Oscillatoriales was observed, with a remarkable number of sequences similar to genera Symphyonemopsis/Brasilonema (order Nostocales). The results demonstrated that phyllosphere cyanobacteria in this mangrove forest ecosystem are influenced by environmental conditions as the primary driver at the ecosystem scale, with tree species exerting some effect on community structure at the local scale.

Pollen analysis of modern mangrove systems

Three sediment cores from the Bragança Peninsula located in the coastal region in the north-eastern portion of Pará State have been studied by pollen analysis to reconstruct Holocene environmental changes and dynamics of the mangrove ecosystem. The cores were taken from an Avicennia forest (Bosque de Avicennia (BDA)), a salt marsh area (Campo Salgado (CS)) and a Rhizophora dominated area (Furo do Chato). Pollen traps were installed in five different areas of the peninsula to study modern pollen deposition. Nine accelerator mass spectrometry radiocarbon dates provide time control and show that sediment deposits accumulated relatively undisturbed. Mangrove vegetation started to develop at different times at the three sites: at 5120 14C yr BP at the CS site, at 2170 14C yr BP at the BDA site and at 1440 14C yr BP at the FDC site. Since mid Holocene times, the mangroves covered even the most elevated area on the peninsula, which is today a salt marsh, suggesting somewhat higher relative sea-levels. The pollen concentration in relatively undisturbed deposits seems to be an indicator for the frequency of inundation. The tidal inundation frequency decreased, probably related to lower sea-levels, during the late Holocene around 1770 14C yr BP at BDA, around 910 14C yr BP at FDC and around 750 14C yr BP at CS. The change from a mangrove ecosystem to a salt marsh on the higher elevation, around 420 14C yr BP is probably natural and not due to an anthropogenic impact. Modern pollen rain from different mangrove types show different ratios between Rhizophora and Avicennia pollen, which can be used to reconstruct past composition of the mangrove. In spite of bioturbation and especially tidal inundation, which change the local pollen deposition within the mangrove zone, past mangrove dynamics can be reconstructed. The pollen record for BDA indicates a mixed Rhizophora/Avicennia mangrove vegetation between 2170 and 1770 14C yr BP. Later Rhizophora trees became more frequent and since ca. 200 14C yr BP Avicennia dominated in the forest.

Mangrove, Crab and Shorebird Activity as Bioindicators to the Health Status of Mangrove Ecosystems along the Surinamese Coastline, South America

This study focused on the shorebird activity along the Surinamese coast in relation to the mangrove ecosystem health. The health of three estuarine mangrove areas was assessed using important bioindicators of the mangrove ecosystem: crabs, birds and mangroves. Mangrove vegetation was measured at Weg Naar Zee, Matapica canal delta and Coronie coast. Crab activity was measured by burrow and crab counts. Occurring shorebirds were also counted at these areas. The results show that mangrove regeneration and shorebird activity is significantly related to the health of the ecosystem. Weg Naar Zee was the most damaged and highest at risk. Matapica canal delta and the Coronie coast were the least damaged, with Coronie coast showing greatest health and biodiversity of the indicators.

Summertime Influences of Tidal Energy Advection on the Surface Energy Balance in a Mangrove Forest

Mangrove forests are ecosystems susceptible to changing water levels and temperatures due to climate change as well as perturbations resulting from tropical storms. Numerical models can be used to project mangrove forest responses to regional and global environmental changes, and the reliability of these models depends on surface energy balance closure. However, for tidal ecosystems, the surface energy balance is complex because the energy transport associated with tidal activity remains poorly understood. This study aimed to quantify impacts of tidal flows on energy dynamics within a mangrove ecosystem. To address the research objective, an intensive 10-day study was conducted in a mangrove forest located along the Shark River in the Everglades National Park, FL, USA. Forest–atmosphere turbulent exchanges of energy were quantified with an eddy covariance system installed on a 30-m-tall flux tower. Energy transport associated with tidal activity was calculated based on a coupled mass and energy balance approach. The mass balance included tidal flows and accumulation of water on the forest floor. The energy balance included temporal changes in enthalpy, resulting from tidal flows and temperature changes in the water column. By serving as a net sink or a source of available energy, flood waters reduced the impact of high radiational loads on the mangrove forest. Also, the regression slope of available energy versus sink terms increased from 0.730 to 0.754 and from 0.798 to 0.857, including total enthalpy change in the water column in the surface energy balance for 30-min periods and daily daytime sums, respectively. Results indicated that tidal inundation provides an important mechanism for heat removal and that tidal exchange should be considered in surface energy budgets of coastal ecosystems. Results also demonstrated the importance of including tidal energy advection in mangrove biophysical models that are used for predicting ecosystem response to changing climate and regional freshwater management practices.

Morphometry and biomass of the cultured mangrove oyster Crassostrea rhizophorae at the Urindeua river, eastern Amazonia, northern Brazil

The malacocultura, particularly oyster farming, appears on the world stage as one of the most viable alternatives to fishing decline and supply of fresh product. In Brazil, the development of mollusc cultivationis through the genus oyster cultivation Crassostrea, among them Crassostrea rhizophorae (Guilding, 1828), known for oyster-the-swamp, one of the main species of farmed bivalves in the state of Pará. This so it aimed to characterize the biomorphometrics relations, estimate the Shape Stabilization Index (IEF) of the shell and the yield of edible meat C. rhizophorae grown in an Amazonian coast, state of Pará, northern Brazil. When all is sampled 1,028 individuals, in April 2016, measuring the external morphometric measures (length, width and height) and total and visceral biomass. The results obtained are C. rhizophorae with (1) excellent biomorphometrics relationships among both external measures, the measures of the shell and biomass generating equations that satisfy morphometric pet species, (2) yield of edible meat 15% of the total biomass and variation in the shell along its development to adulthood, with a tendency to stabilize the reach 60mm in length.

Anthropogenic impact on diazotrophic diversity in the mangrove rhizosphere revealed by nifH pyrosequencing

Diazotrophs in the mangrove rhizosphere play a major role in providing new nitrogen to the mangrove ecosystem and their composition and activity are strongly influenced by anthropogenic activity and ecological conditions. In this study, the diversity of the diazotroph communities in the rhizosphere sediment of five tropical mangrove sites with different levels of pollution along the north and south coastline of Singapore were studied by pyrosequencing of the nifH gene. Bioinformatics analysis revealed that in all the studied locations, the diazotroph communities comprised mainly of members of the diazotrophic cluster I and cluster III. The detected cluster III diazotrophs, which were composed entirely of sulfate-reducing bacteria, were more abundant in the less polluted locations. The metabolic capacities of these diazotrophs indicate the potential for bioremediation and resiliency of the ecosystem to anthropogenic impact. In heavily polluted locations, the diazotrophic community structures were markedly different and the diversity of species was significantly reduced when compared with those in a pristine location. This, together with the increased abundance of Marinobacterium, which is a bioindicator of pollution, suggests that anthropogenic activity has a negative impact on the genetic diversity of diazotrophs in the mangrove rhizosphere.