938 resultados para Coastal and estuarine stations


Relevância:

100.00% 100.00%

Publicador:

Resumo:

No serious attempt has so far been made in India to make use of the ‘Mussel watch’ concept as a useful tool for pollution monitoring of the marine and estuarine environment. The recently conducted 'National seminar on mussel watch’ by the Cochin University of Science and Technology (13-14 Feb, 1986) discussed the technical aspects related to mussel watch programme and the application of sentinel organism concept to the coastal areas of India. It is well known that the biological and physiological characteristics of the organism inhabiting tropical waters such as those prevailing in India, and the ecological as well as the environmental characteristics of temperate areas, where mussel watch programmes are already in existence differ greatly. So it is essential to adopt the techniques and standards developed for temperate species to the situations and conditions in India. In this context it is a prerequisite to collect information on physiology and other biological indices of stress of possible sentinel organisms like P.viridis. In consideration of the above, P. viridis which is a potential sentinel organism, is selected for the present study

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Sedimentary biomarker pigments around Cochin estuary situated in the southwest coast of India were determined by HPLC. Fucoxanthin, an indicator of diatom was observed to be the most abundant carotenoid pigment in the estuary. Dinoflagellate derived carotenoid pigment peridinin was confined in the southern part of estuary and zeaxanthin pigment indicative of cyanobacteria were more found in sites influenced by anthropogenic activities. One compound having close similarity to fucoxanthin was also detected. Alloxanthin (cryptophyceae), chl b (green algae), canthaxanthin, neoxanthin, lutein and peridinin isomer were also detected by spectra and corresponding algal class were identified. The highest concentration of chl a (11.01 mg g 1) found near to the anthropogenic affected area while the lowest chl a (0.65 mg g 1) was recorded in industrial area. Degradation products of chl a, such as pheophorbide and pheophytin were observed and principal mode of mechanism of degradation were derived. Higher pheopigments content than chl a, reflects a density trapping of dead cells and early degradation of phytopigments from grazing activities

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The main objectives of the study are: To study the seasonal distribution of copepods with special reference to their qualitative and quantitative distribution, with notes on biodiversity in the Andaman Sea and the Bay of Bengal. To study the spatial and temporal distribution of copepods in the Andaman Sea and the Bay of Bengal.To understand the hydrography and the environmental characteristics of the Andaman Sea and the Bay of Bengal and their role in the distribution and biomass of copepods.To study the vertical migration/diurnal migration of the copepods. To study the difference between the coastal and oceanic composition of copepods in the study area and the factors responsible for it.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The genus Vibrioof the family Vibrionaceae are Gram negative, oxidasepositive, rod- or curved- rodshaped facultative anaerobes, widespread in marine and estuarine environments. Vibrio species are opportunistic human pathogens responsible for diarrhoeal disease, gastroenteritis, septicaemia and wound infections and are also pathogens of aquatic organisms, causing infections to crustaceans, bivalves and fishes. In the present study, marine environmental samples like seafood and water and sediment samples from aquafarms and mangroves were screened for the presence of Vibrio species. Of the134 isolates obtained from the various samples, 45 were segregated to the genus Vibrio on the basis of phenotypic characterization.like Gram staining, oxidase test, MoF test and salinity tolerance. Partial 16S rDNA sequence analysis was utilized for species level identification of the isolates and the strains were identified as V. cholerae(N=21), V. vulnificus(N=18), V. parahaemolyticus(N=3), V. alginolyticus (N=2) and V. azureus (N=1). The genetic relatedness and variations among the 45 Vibrio isolates were elucidated based on 16S rDNA sequences. Phenotypic characterization of the isolates was based on their response to 12 biochemical tests namely Voges-Proskauers’s (VP test), arginine dihydrolase , tolerance to 3% NaCl test, ONPG test that detects β-galactosidase activity, and tests for utilization of citrate, ornithine, mannitol, arabinose, sucrose, glucose, salicin and cellobiose. The isolates exhibited diverse biochemical patterns, some specific for the species and others indicative of their environmental source.Antibiogram for the isolates was determined subsequent to testing their susceptibility to 12 antibiotics by the disc diffusion method. Varying degrees of resistance to gentamycin (2.22%), ampicillin(62.22%), nalidixic acid (4.44%), vancomycin (86.66), cefixime (17.77%), rifampicin (20%), tetracycline (42.22%) and chloramphenicol (2.22%) was exhibited. All the isolates were susceptible to streptomycin, co-trimoxazole, trimethoprim and azithromycin. Isolates from all the three marine environments exhibited multiple antibiotic resistance, with high MAR index value. The molecular typing methods such as ERIC PCR and BOX PCR revealed intraspecies relatedness and genetic heterogeneity within the environmental isolatesof V. cholerae and V. vulnificus. The 21 strains of V. choleraewere serogroupedas non O1/ non O139 by screening for the presence O1rfb and O139 rfb marker genes by PCR. The virulence/virulence associated genes namely ctxA, ctxB, ace, VPI, hlyA, ompU, rtxA, toxR, zot, nagst, tcpA, nin and nanwere screened in V. cholerae and V. vulnificusstrains.The V. vulnificusstrains were also screened for three species specific genes viz., cps, vvhand viu. In V. cholerae strains, the virulence associated genes like VPI, hlyA, rtxA, ompU and toxR were confirmed by PCR. All the isolates, except for strain BTOS6, harbored at least one or a combination of the tested genes and V. choleraestrain BTPR5 isolated from prawn hosted the highest number of virulence associated genes. Among the V. vulnificusstrains, only 3 virulence genes, VPI, toxR and cps, were confirmed out of the 16 tested and only 7 of the isolates had these genes in one or more combinations. Strain BTPS6 from aquafarm and strain BTVE4 from mangrove samples yielded positive amplification for the three genes. The toxRgene from 9 strains of V. choleraeand 3 strains of V. vulnificus were cloned and sequenced for phylogenetic analysis based on nucleotide and the amino acid sequences. Multiple sequence alignment of the nucleotide sequences and amino acid sequences of the environmental strains of V. choleraerevealed that the toxRgene in the environmental strains are 100% homologous to themselves and to the V. choleraetoxR gene sequence available in the Genbank database. The 3 strains of V. vulnificus displayed high nucleotide and amino acid sequence similarity among themselves and to the sequences of V. cholerae and V. harveyi obtained from the GenBank database, but exhibited only 72% homology to the sequences of its close relative V. vulnificus. Structure prediction of the ToxR protein of Vibrio cholerae strain BTMA5 was by PHYRE2 software. The deduced amino acid sequence showed maximum resemblance with the structure of DNA-binding domain of response regulator2 from Escherichia coli k-12 Template based homology modelling in PHYRE2 successfully modelled the predicted protein and its secondary structure based on protein data bank (PDB) template c3zq7A. The pathogenicity studies were performed using the nematode Caenorhabditiselegansas a model system. The assessment of pathogenicity of environmental strain of V. choleraewas conducted with E. coli strain OP50 as the food source in control plates, environmental V. cholerae strain BTOS6, negative for all tested virulence genes, to check for the suitability of Vibrio sp. as a food source for the nematode;V. cholerae Co 366 ElTor, a clinical pathogenic strain and V. cholerae strain BTPR5 from seafood (Prawn) and positive for the tested virulence genes like VPI, hlyA, ompU,rtxA and toxR. It was found that V. cholerae strain BTOS6 could serve as a food source in place of E. coli strain OP50 but behavioral aberrations like sluggish movement and lawn avoidance and morphological abnormalities like pharyngeal and intestinal distensions and bagging were exhibited by the worms fed on V. cholerae Co 366 ElTor strain and environmental BTPR5 indicating their pathogenicity to the nematode. Assessment of pathogenicity of the environmental strains of V. vulnificus was performed with V. vulnificus strain BTPS6 which tested positive for 3 virulence genes, namely, cps, toxRand VPI, and V. vulnificus strain BTMM7 that did not possess any of the tested virulence genes. A reduction was observed in the life span of worms fed on environmental strain of V. vulnificusBTMM7 rather than on the ordinary laboratory food source, E. coli OP50. Behavioral abnormalities like sluggish movement, lawn avoidance and bagging were also observed in the worms fed with strain BTPS6, but the pharynx and the intestine were intact. The presence of multi drug resistant environmental Vibrio strainsthat constitute a major reservoir of diverse virulence genes are to be dealt with caution as they play a decisive role in pathogenicity and horizontal gene transfer in the marine environments.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

This is an empirical study with theoretical interpretation and elaboration simultaneously on the migration process and the related spatial development in contemporary China. In so doing, there is always a combination of series of studies of the modernization of the migrants themselves with accumulation of forms of capital and changes of lebenswelt (life world) as well as the regions of their origins by the effective use of the gained resources from outgoing migration and remigration. With great efforts made to put the issues together for analysis, the author has taken three approaches to the study based on the political and economic institutional arrangements, the field work data and the elaboration of respective findings. First, as the analytical parts of the institutional changes, which have gone through the whole research, many of the policies from state level to townships involved in the migration, remigration and spatial development have been interpreted with Chinese political and cultural insight. The making of these, as the means of understanding the contexts of macro level and micro level cases is served as key linkages between scholarly imagination and social reality. Indeed most of the discussions made to explain the phenomena such as the sudden upsurge of migration flows, the emergence of three generations, the strong and weak trends of remigration as well as the related spatial development planning, etc are mainly due to the domination, at least the impact of governments decision-making in spite of growing market functioning in often operative manners. Secondly, case studies of the effects of migration and remigration are carried out between the years of 1995 and 2005 in the costal urban regions as designations and the interior rural regions as origins. Conducted mainly by the author, the cases drawn in the research focus on the process of migration with an accumulation of forms of capital away from home and the effective use of the resources flowing back to home areas. As a result, ways of accumulation and utilization of the economic, social and cultural capital are described and interpreted in terms of the development and modernization of both the migrants themselves and the regions where they come out from or move to in the future. Thirdly, in accordance with the findings generated from the cases, the author proposes in the final chapter an important argumentation as conclusion that the duel social-economic structure will inevitably be broken up and reformulated with flows of migrants and forms of capital they possess as types of future spatial development that will be put into practice. With scenarios and all the other conclusions worked out in the end, the research concludes that the pluralistic spatial development in the condition of constant space flows between regions can be a decisive line of thinking in the process of urbanization, industrialization and modernization in the long run in the future. Since this is an exploratory study of the past and present, the author has left some space open for academic debates and put forward suggestions on the inclusion of future research before implementing policies necessary for migration associated spatial practice and development.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Ante el crecimiento económico y la transformación del país. Con el incremento de los flujos de comercio y el transporte, Bogotá, buscando reducir el impacto ambiental por la cantidad de vehículos y reducir la congestión, ha decidido implementar políticas públicas que restringen el ingreso de vehículos de carga pesada por la ciudad. Esto crea una necesidad de espacios a las afueras de la ciudad, cerca de las zonas logísticas y con la capacidad de ofrecer a los transportadores los servicios de alimentación, parqueadero, alojamiento y reabastecimiento de combustible. Atendiendo estas necesidades, Stop And Go surge como proyecto de inversión que pretende constituir un espacio eficazmente equipado, con altos estándares de calidad y de bajo costo. En el presente documento se desarrolla el plan de negocios y de viabilidad, recorriendo la estructura de la organización, las características de los servicios ofrecidos, la propuesta de mercadeo y la viabilidad estratégica y financiera.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Field studies were carried out on the water and sediment dynamics in the tropical, macro-tidal, Daly Estuary. The estuary is shallow, very-turbid, about 100 km long, and the entrance is funnel-shape. In the wet, high flow season, normal tidal ranges can be suppressed in the estuary, depending on inflow rates, and freshwater becomes dominant up to the mouth. At that time a fraction of the fine sediment load is exported offshore as a bottom-tagging nepheloid layer after the sediment falls out of suspension of the thin, near-surface, river plume. The remaining fraction and the riverine coarse sediment form a large sediment bar 10 km long, up to 6 m in height and extending across the whole width of the channel near the mouth. This bar, as well as shoals in the estuary, partially pond the mid- to upper-estuary. This bar builds up from the deposition of riverine sediment during a wet season with high runoff and can raise mean water level by up to 2 m in the upper estuary in the low flow season. This ponding effect takes about three successive dry years to disappear by the sediment forming the bar being redistributed all over the estuary by tidal pumping of fine and coarse sediment in the dry season, which is the low flow season. The swift reversal of the tidal currents from ebb to flood results in macro-turbulence that lasts about 20 min. Bed load transport is preferentially landward and occurs only for water currents greater than 0.6 m s(-1). This high value of the threshold velocity suggests that the sand may be cemented by the mud. The Daly Estuary thus is a leaky sediment trap with an efficiency varying both seasonally and inter-annually. (c) 2006 Elsevier Ltd. All rights reserved.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Accuracy and mesh generation are key issues for the high-resolution hydrodynamic modelling of the whole Great Barrier Reef. Our objective is to generate suitable unstructured grids that can resolve topological and dynamical features like tidal jets and recirculation eddies in the wake of islands. A new strategy is suggested to refine the mesh in areas of interest taking into account the bathymetric field and an approximated distance to islands and reefs. Such a distance is obtained by solving an elliptic differential operator, with specific boundary conditions. Meshes produced illustrate both the validity and the efficiency of the adaptive strategy. Selection of refinement and geometrical parameters is discussed. (c) 2006 Elsevier Ltd. All rights reserved.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Broadband shortwave and longwave radiative fluxes observed both at the surface and from space during the Radiative Atmospheric Divergence using ARM Mobile Facility, GERB data and AMMA Stations (RADAGAST) experiment in Niamey, Niger, in 2006 are presented. The surface fluxes were measured by the Atmospheric Radiation Measurement (ARM) Program Mobile Facility (AMF) at Niamey airport, while the fluxes at the top of the atmosphere (TOA) are from the Geostationary Earth Radiation Budget (GERB) instrument on the Meteosat-8 satellite. The data are analyzed as daily averages, in order to minimize sampling differences between the surface and top of atmosphere instruments, while retaining the synoptic and seasonal changes that are the main focus of this study. A cloud mask is used to identify days with cloud versus those with predominantly clear skies. The influence of temperature, water vapor, aerosols, and clouds is investigated. Aerosols are ubiquitous throughout the year and have a significant impact on both the shortwave and longwave fluxes. The large and systematic seasonal changes in temperature and column integrated water vapor (CWV) through the dry and wet seasons are found to exert strong influences on the longwave fluxes. These influences are often in opposition to each other, because the highest temperatures occur at the end of the dry season when the CWV is lowest, while in the wet season the lowest temperatures are associated with the highest values of CWV. Apart from aerosols, the shortwave fluxes are also affected by clouds and by the seasonal changes in CWV. The fluxes are combined to provide estimates of the divergence of radiation across the atmosphere throughout 2006. The longwave divergence shows a relatively small variation through the year, because of a partial compensation between the seasonal variations in the outgoing longwave radiation (OLR) and surface net longwave radiation. A simple model of the greenhouse effect is used to interpret this result in terms of the dependence of the normalized greenhouse effect at the TOA and of the effective emissivity of the atmosphere at the surface on the CWV. It is shown that, as the CWV increases, the atmosphere loses longwave energy to the surface with about the same increasing efficiency with which it traps the OLR. When combined with the changes in temperature, this maintains the atmospheric longwave divergence within the narrow range that is observed. The shortwave divergence is mainly determined by the CWV and aerosol loadings and the effect of clouds is much smaller than on the component fluxes.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The archaeological evidence compiled for Liguria has enabled the formulation of a comprehensive model of Neolithic social, technological and economic development (∼7800–5700 cal yrs BP). The model indicates that during the Early and Middle Neolithic (∼7800–6300 cal yrs BP; ‘Impressed Ware’ and ‘Square Mouthed’ pottery cultures) human activity mainly focussed on low (coastal) and mid-altitude areas. By the Late Neolithic (∼6300–5700 cal yrs BP; ‘Chassey’ culture) farming practices were taking place over a wider range of altitudes and involved transhumant pastoralism. Complementary environmental archaeological and palaeoecological records from caves, open-air sites, lakes and mires indicate that human activities had a more significant impact on the environment than previously thought. This included clearance, especially Abies, Ulmus, Fraxinus and Tilia, and woodland utilisation and management (e.g. leaf foddering), as well as cereal cultivation and animal husbandry. The influence of Middle Holocene climatic changes, especially from ∼7800 cal yrs BP, on the direction of vegetation changes and socio-economic developments during the Neolithic remain uncertain.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

A comprehensive atmospheric boundary layer (ABL) data set was collected in eight fi eld experiments (two during each season) over open water and sea ice in the Baltic Sea during 1998–2001 with the primary objective to validate the coupled atmospheric- ice-ocean-land surface model BALTIMOS (BALTEX Integrated Model System). Measurements were taken by aircraft, ships and surface stations and cover the mean and turbulent structure of the ABL including turbulent fl uxes, radiation fl uxes, and cloud conditions. Measurement examples of the spatial variability of the ABL over the ice edge zone and of the stable ABL over open water demonstrate the wide range of ABL conditions collected and the strength of the data set which can also be used to validate other regional models.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The potential changes to the territory of the Russian Arctic open up unique possibilities for the development of tourism. More favourable transport opportunities along the Northern Sea Route (NSR) create opportunities for tourism development based on the utilisation of the extensive areas of sea shores and river basins. A major challenge for the Russian Arctic sea and river ports is their strong cargo transport orientation originated by natural resource extraction industries. A careful assessment of the prospects of current and future tourism development is presented here based on the development of regions located along the shores of the Arctic ocean (including Murmansk and Arkhangelsk oblast, Nenets Autonomous okrug (AO), Yamal-Nenets AO, Taymyr AO, Republic of Sakha, Chykotsky AO). An evaluation of the present development of tourism in maritime cities suggests that a considerable qualitative and quantitative increase of tourism activities organised by domestic tourism firms is made virtually impossible. There are several factors contributing to this. The previously established Soviet system of state support for the investments into the port facilities as well as the sea fleet were not effectively replaced by creation of new structures. The necessary investments for reconstruction could be contributed by the federal government but the priorities are not set towards the increased passenger transportation. Having in mind, increased environmental pressures in this highly sensitive area it is especially vital to establish a well-functioning monitoring and rescue system in the situation of ever increasing risks which come not only from the increased transports along the NSR, but also from the exploitation of the offshore oil and gas reserves in the Arctic seas. The capacity and knowledge established in Nordic countries (Norway, Finland) concerning cruise tourism should not be underestimated and the already functioning cooperation in Barents Region should expand towards this particular segment of the tourism industry. The current stage of economic development in Russia makes it clear that tourism development is not able to compete with the well-needed increase in the cargo transportation, which means that Russia’s fleet is going to be utilised by other industries. However, opening up this area to both local and international visitors could contribute to the economic prosperity of these remote areas and if carefully managed could sustain already existing maritime cities along the shores of the Arctic Ocean.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Maine's 3,500 miles of coastline is the longest coastline in the continental US. The goal of our study was to use GIS to estimate the impact future global sea level rise could potentially have on our state. We show the area of coastline and some of the economic and social impacts that would result from a rise of one meter and six meters. We used roads to estimate the impact on infrastructure and public building, including schools, libraries, hospitals, police and fire stations, as a measure of social impact. A sea level rise of six meters would result in a loss of over 650 km¬2 from coastal communities and cost the state of Maine over 3 million in repaving costs. Through our study, we hope coastal communities will be able to prepare for and react to the predicted changes in global sea level.