973 resultados para Coastal Ecosystems


Relevância:

60.00% 60.00%

Publicador:

Resumo:

Dissertação de mestrado, Biologia Marinha, Faculdade de Ciências e Tecnologia, Universidade do Algarve, 2015

Relevância:

60.00% 60.00%

Publicador:

Resumo:

Members of the order Mysidacea are important component in marine and estuarine plankton inhabiting all regions of the oceans. There are many brackish water species and few species occur in fresh water, some have become adapted to the specialized environments of caves and wells. They are omnivores, responsible for remineralisation of a substantial portion of the detritus in the water column. They form an important link in the food chain (between microbial producers and secondary consumers) and therefore play a major role in the cycling of energy within the aquatic ecosystem. In tropical and subtropical waters, swarms of mysids are exploited commercially and marketed as preserved cooked food. Mysids have been used in fish farming as live feed resource. They are also excellent experimental organism, extremely useful in the studies of potential impact of various pollutants in the aquatic environment. Mysids are also used in wood pulp effluent plants.Considering the significant role of mysids in the productivity of tropical and coastal ecosystems,the present study has been undertaken to extend our knowledge on the systematics, species composition, distribution,abundance and ecology of mysid fauna of the Indian EEZ and adjoining areas. The present study therefore will undoubtedly fumish valuable information on Mysidacea of the Indian waters.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

This thesis entitled triterpenoids as biomarkers of mangrove organic matter in cochin estuarine system.Mangrove forests, known as rainforests of the sea are one of the most important coastal ecosystems in the world in terms of primary production and coastal protection.Estuaries, the important areas of world’s coastal zones link the carbon cycle of the oceans to the continents.Three mangrove ecosystems and three estuarine stations around Cochin region, southwest coast of India were selected for the present study. The thesis is divided into five chapters. Chapter 1 is the Introduction and it deals with the aim and scope of the present study. Chapter 2 is Materials and Methods. This chapter deals with the nature and general geographical features of the study area. It also contains the details of the sampling and analytical methodology.the present study. Chapter 3 is Geochemistry and it includes the seasonal and spatial variations of the geochemical parameters in the surface sediments.Chapter 4 is Biochemical Composition. It covers the biochemical composition of organic matter in the surface sediments to examine the quality and quantity of organic matter.Chapter 5, Triterpenoid Biomarkers in Sediments, characterize the organic matter in the sediments of the mangrove and estuarine ecosystems under study, to assess the possible sources with the help of triterpenoid biomarkers along with other lipid biomarkers.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

In India a study conducted by CIFE and CIBA (1997), concluded that shrimp farming does more good than harm and it is not eco-unfriendly (Krishnan and Birthal, 2002). Upsurge in coastal aquaculture activity induced by high profitability is reported to have caused adverse impacts on coastal ecosystems and social environments (Parthasarathy and Nirmala, 2000). The crustacean farming sector has received criticism for excessive use of formulated feed containing high protein, of which around 50% gets accumulated at the pond bottom as unconsumed (Avnimelech, 1999; Hari et al., 2004, 2006). The wasted feeds undergo the process of degradation and results in the release of toxic metabolites to the culture system. Reduction of protein in the feed, manipulation and utilisation of natural food in the culture system are the remedy for the above problems. But before reducing the feed protein, it should be confirmed that the feed with reduced protein is not affecting the growth and health of the cultured animal. In the present study, biofloc technology is identified as one of the innovative technologies for ensuring the ecological and environmental Sustainability and examines the compatibility of BFT for the sustainable aquaculture of giant prawn, M. rosenbergii. This thesis starts with a general introduction (Chapter-1), a brief review of the most relevant literature (Chapter-2), results of various experiments (Chapter-3-6), summary (Chapter-7) and recommendations and future research perspectives in the field of biofloc based aquaculture (Chapter – 8). The major objectives of this thesis are, to improve the ecological and economical sustainability of prawn farming by the applicationof BFT and to improve the nutrient utilisation in aquaculture systems.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

Heavy metals in the surface sediments of the two coastal ecosystems of Cochin, southwest India were assessed. The study intends to evaluate the degree of anthropogenic influence on heavy metal concentration in the sediments of the mangrove and adjacent estuarine stations using enrichment factor and geoaccumulation index. The inverse relationship of Cd and Zn with texture in the mangrove sediments suggested the anthropogenic enrichment of these metals in the mangrove systems. In the estuarine sediments, the absence of any significant correlation of the heavy metals with other sedimentary parameters and their strong interdependence revealed the possibility that the input is not through the natural weathering processes. The analysis of enrichment factor indicated a minor enrichment for Pb and Zn in mangrove sediments. While, extremely severe enrichment for Cd, moderate enrichment for Zn and minor enrichment of Pb were observed in estuarine system. The geo accumulation index exhibited very low values for all metals except Zn, indicating the sediments of the mangrove ecosystem are unpolluted to moderately polluted by anthropogenic activities. However, very strongly polluted condition for Cd and a moderately polluted condition for Zn were evident in estuarine sediments

Relevância:

60.00% 60.00%

Publicador:

Resumo:

To analyze patterns in marine productivity, harmful algal blooms, thermal stress in coral reefs, and oceanographic processes, optical and biophysical marine parameters, such as sea surface temperature, and ocean color products, such as chlorophyll-a concentration, diffuse attenuation coefficient, total suspended matter concentration, chlorophyll fluorescence line height, and remote sensing reflectance, are required. In this paper we present a novel automatic Satellite-based Ocean Monitoring System (SATMO) developed to provide, in near real-time, continuous spatial data sets of the above-mentioned variables for marine-coastal ecosystems in the Gulf of Mexico, northeastern Pacific Ocean, and western Caribbean Sea, with 1 km spatial resolution. The products are obtained from Moderate Resolution Imaging Spectroradiometer (MODIS) images received at the Direct Readout Ground Station (located at CONABIO) after each overpass of the Aqua and Terra satellites. In addition, at the end of each week and month the system provides composite images for several ocean products, as well as weekly and monthly anomaly composites for chlorophyll-a concentration and sea surface temperature. These anomaly data are reported for the first time for the study region and represent valuable information for analyzing time series of ocean color data for the study of coastal and marine ecosystems in Mexico, Central America, and the western Caribbean.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

Nutrient discharge into coastal areas, such as the Great Barrier Reef can result in the degradation of coastal ecosystems. For example, excess nitrogen and phosphorus can damage corals through inducing algal bloom and subsequent shading. Excessive phosphorus can further weaken coral skeletons making them susceptible to damage. Land based industries such as aquaculture can contribute to such problems. This study set out to develop a system whereby water from aquaculture can be constantly reused resulting in minimized waste discharge. A three-stage filtration system utilizing floating media and activated carbon was designed to harness bacterial processes that could reduce both particulate and dissolved compounds to the extent whereby approximately 100% reuse of the wastewater became possible. This involved efficient and effective particulate and biological removal mechanisms in both aerobic and anaerobic zones of the filtration system. This design reduced dissolved nitrogen levels by up to 70% and maintained low phosphorus levels, which allowed the reuse of water for the successful culture of barramundi with a survival rate of 97% over 25 days. This pilot scale study demonstrated the potential of reusing aquaculture wastewater from the viewpoint of reducing nutrient input into coastal environments. Future research will refine these processes and assess the performance of the system at several commercial scale applications.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

Here, we evaluated the potential of using bathymetric Light Detection and Ranging (LiDAR) to characterise shallow water (<30 m) benthic habitats of high energy subtidal coastal environments. Habitat classification, quantifying benthic substrata and macroalgal communities, was achieved in this study with the application of LiDAR and underwater video groundtruth data using automated classification techniques. Bathymetry and reflectance datasets were used to produce secondary terrain derivative surfaces (e.g., rugosity, aspect) that were assumed to influence benthic patterns observed. An automated decision tree classification approach using the Quick Unbiased Efficient Statistical Tree (QUEST) was applied to produce substrata, biological and canopy structure habitat maps of the study area. Error assessment indicated that habitat maps produced were primarily accurate (>70%), with varying results for the classification of individual habitat classes; for instance, producer accuracy for mixed brown algae and sediment substrata, was 74% and 93%, respectively. LiDAR was also successful for differentiating canopy structure of macroalgae communities (i.e., canopy structure classification), such as canopy forming kelp versus erect fine branching algae. In conclusion, habitat characterisation using bathymetric LiDAR provides a unique potential to collect baseline information about biological assemblages and, hence, potential reef connectivity over large areas beyond the range of direct observation. This research contributes a new perspective for assessing the structure of subtidal coastal ecosystems, providing a novel tool for the research and management of such highly dynamic marine environments. © 2014 by the authors; licensee MDPI, Basel, Switzerland.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

Macroalgal communities in Australia and around the world store vast quantities of carbon in their living biomass, but their prevalence of growing on hard substrata means that they have limited capacity to act as long-term carbon sinks. Unlike other coastal blue carbon habitats such as seagrasses, saltmarshes and mangroves, they do not develop their own organic-rich sediments, but may instead act as a rich carbon source and make significant contributions in the form of detritus to sedimentary habitats by acting as a “carbon donor” to “receiver sites” where organic material accumulates. The potential for storage of this donated carbon however, is dependent on the decay rate during transport and the burial efficiency at receiver sites. To better understand the potential contribution of macroalgal communities to coastal blue carbon budgets, a comprehensive literature search was conducted using key words, including carbon sequestration, macroalgal distribution, abundance and productivity to provide an estimation of the total amount of carbon stored in temperate Australian macroalgae. Our most conservative calculations estimate 109.9 Tg C is stored in living macroalgal biomass of temperate Australia, using a coastal area covering 249,697 km2. Estimates derived for tropical and subtropical regions contributed an additional 23.2 Tg C. By extending the search to include global studies we provide a broader context and rationale for the study, contributing to the global aspects of the review. In addition, we discuss the potential role of calcium carbonate-containing macroalgae, consider the dynamic nature of macroalgal populations in the context of climate change, and identify the knowledge gaps that once addressed will enable robust quantification of macroalgae in marine biogeochemical cycling of carbon. We conclude that macroalgal communities have the potential to make ecologically meaningful contributions toward global blue carbon sequestration, as donors, but given that the fate of detached macroalgal biomass remains unclear, further research is needed to quantify this contribution.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

Aerial imagery collected before and after major storm events is ideal for the assessment of coastal landscape change driven by individual high-magnitude events. Using traditional satellite sensors and manned aerial systems can be challenging due to issues related to cloud cover, mobilization expenses and resolution. Rapid advances in unmanned aerial vehicle (UAV) technology allow for the cost-effective collection of aerial imagery and topography at centimetre resolution suitable for assessing change in coastal ecosystems. In this study we demonstrate the utility of UAV-based photogrammetry to quantify storm-driven sediment dynamics on a sandy beach on the open-coast shoreline of Victoria, Australia. UAV-based aerial photography was collected before and after a major storm event. High-resolution (< 5 cm) aerial imagery and digital surface models were acquired and change-detection techniques were applied to quantify changes in the beachface. An average beach erosion of 12.24 m3/m with a maximum of 28.05 m3/m was observed, and the volume of sand cut from the beachface and retreat of the foredune are clearly illustrated. Following the storm event, erosion was estimated at 7259.94 ± 503.69 m3 along 550 m of beach. By combining the aerial imagery and derived topographic datasets we demonstrate the advantage of UAV-based photogrammetry techniques for rapid high-resolution data collection in semi-remote locations. Its utility in setting unlimited virtual vantage points is also illustrated and the valuable perspective it provides for tracking landscape change discussed.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

Sea urchins are common benthic organisms on coastal ecosystems of tropical and temperate shallow waters. The impact of sea urchins populations in shore communities is density-dependent, and therefore, knowledge of the life history of these animals is important to understand these interactions. Between 2000 and 2005 a population boom of Tripneustes ventricosus was observed in the Fernando de Noronha Archipelago. In 2004 a research program was started to monitor the population dynamics of T. ventricosus in the archipelago, when it noted a lack of basic information on the biology and reproduction of this species, despite its broad geographic distribution and economic importance in parts of its occurrence. In this context, this work focuses on the reproductive biology of T. ventricosus with emphasis on the description of the gametogenic stages. Between December 2006 and July 2007, ten urchins were collected by snorkeling in two sites of the archipelago, totaling 120 individuals. Gametogenic stages were described for both sexes through microscopic analysis, and were defined as: Recovery, Growing, Premature, Mature and Spawning. Results showed increasing in Gonad index throughout of months of sampling and suggest that the reproductive cycle of the species in the archipelago is annual

Relevância:

60.00% 60.00%

Publicador:

Resumo:

The oil activity in the Rio Grande do Norte State (RN) is a permanent threat to coastal ecosystems, particularly mangroves, with the possibility of oil spills. In this context, the objective of this study was to evaluate the potential resistance of the mangrove environment of a possible spill. Were selected and isolated microorganisms degrading oil by the technique of enrichment cultures and formation of a bacterial consortium. The kinetic study of the consortium was held in rotary incubator shaken at 150 rpm and 30° C. Samples were taken at intervals of 4 hours for analysis of cell concentration and surface tension. The biodegradation was monitored using two methods of respirometry: manometric (OxiTop-C ®) and conductivimetry, where the biodegradation of oil was estimated indirectly by oxygen consumption and CO2 production, respectively. Furthermore, it was used a full 2² factorial design with triplicate at central point to the runs that used the conductivimetric methodology.. The technique of enrichment cultures allowed to obtain thirteen bacterial strains. Kinetic study of the consortium, we can showed the absence of the lag phase, reaching a maximum cell concentration of 2.55 g / L at 16 h of cultivation and a reduction on surface tension. When we adopted the methodology of OxiTop-C was detected a band indicating biodegradability (1% oil v/v), however when we used the conductivimetry methodology did not observe any band that would indicate effective biodegradation. By monitoring a process of biodegradation is necessary to observe the methodology will be adopted to evaluate the biodegradation process, since for the same conditions adopted different methodologies can produce different results. The oil-degrading isolates from soils of the mangrove estuary Potengi / RN are largely to be used in bioremediation strategies of these places, in the case of a possible oil spill, or it can be used in the treatment of waste oil generated in saline environments, since they are optimized the conditions of the tests so that the efficiency of biodegradation reach the minimum level suggested by the standarts

Relevância:

60.00% 60.00%

Publicador:

Resumo:

The Brazilian coast has a wide variety of complex environments and ecosystems along the coast, about 80% are represented by sandbanks and dunes. The coastal ecosystems were the first to suffer the impacts man and places, as the very fragile ecosystems, are somehow altered. Are few areas of restinga well as natural features, very few protected in conservation units. Only in the last two decades the Brazilian restinga have been studies that are showing their importance for biodiversity of the country, though its economic importance remains largely unknown. In Rio Grande do Norte in the restinga vegetation and dune environments extend for almost the entire coast. The dunes are distinguished in the coastal landscape of the state due to the exuberance of its forms, heights and coating plants. The dune system is of fundamental importance for the maintenance of coastal urban settlements, especially for the city of Natal, acting on the hydrological dynamics of water table and reducing the effect of wind and movement of grains of sand to the interior and thus avoiding the burial City. However, the ecosystem of restinga and dune environments have been weakened and destroyed according to the intense urbanization and the knowledge of the vegetation of restinga installed on the dunes are still scarce. Thus, the objective of this study was to characterize the structure and floristic composition of vegetation established on a dune in the Dunes State Park Christmas and gather information to develop a model of recovery of the dune ecosystem. This dissertation is composed of 2 chapters, the first being: Structure of the vegetation of the dunes Dunes State Park in Natal, RN with the objective of describing the structure and composition of species of tree-shrub vegetation of restinga dunes of the Parque das Dunas and second: Recovery of degraded areas in a sand dune, which aimed to review the terms and concepts used in the theme of recovery and the techniques for recovery of degraded areas with emphasis on sandy environments and poor in nutrients, reporting some experiences within and external to Brazil the country, mainly in the Northeast and dunes positive and negative aspects that should be followed in building a model to be adopted for the recovery of local dunes

Relevância:

60.00% 60.00%

Publicador:

Resumo:

The mangrove ecosystem has a great importance to maintaining marine biodiversity, and to the livelihoods of communities living around it. Despite its importance, many mangrove areas have been extensively cleared and converted to other uses. There are few places where communities can retain their traditional uses of mangrove. A good example of conservation of traditional costumes are the fishing communities of the Sustainable Development Reserve (Reserva de Desenvolvimento Sustentável RDS) Ponta do Tubarão. The creation of the reserve came from the own population, and the devastation of a mangrove area, which would be destined for activity shrimp, was one of the reasons that led the population to ask authorities the establishment of a legally protected area. Thus, this study aimed to investigate the environmental perception of the fishing communities of RDS Ponta do Tubarão with respect to the mangroves in a biological, ecological and social perspective as well as evaluate the influence of the reserve in the mangrove conservation and quality of life. To meet objectives of this study was required the appropriation of some method and approaches of ethnosciences and environmental perception. Data were collected through direct observation, and semi-structured interviews. Through content analysis found that the population has a strong dependence on the mangrove ecosystem, as well as provides a good ecological knowledge of ecosystem functions. It was also found that the reservation has a good performance in the conservation of the mangroves; however, need to outline strategies to conciliate both the biological and cultural conservation.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

The mangrove ecosystem has a great importance to maintaining marine biodiversity, and to the livelihoods of communities living around it. Despite its importance, many mangrove areas have been extensively cleared and converted to other uses. There are few places where communities can retain their traditional uses of mangrove. A good example of conservation of traditional costumes are the fishing communities of the Sustainable Development Reserve (Reserva de Desenvolvimento Sustentável RDS) Ponta do Tubarão. The creation of the reserve came from the own population, and the devastation of a mangrove area, which would be destined for activity shrimp, was one of the reasons that led the population to ask authorities the establishment of a legally protected area. Thus, this study aimed to investigate the environmental perception of the fishing communities of RDS Ponta do Tubarão with respect to the mangroves in a biological, ecological and social perspective as well as evaluate the influence of the reserve in the mangrove conservation and quality of life. To meet objectives of this study was required the appropriation of some method and approaches of ethnosciences and environmental perception. Data were collected through direct observation, and semi-structured interviews. Through content analysis found that the population has a strong dependence on the mangrove ecosystem, as well as provides a good ecological knowledge of ecosystem functions. It was also found that the reservation has a good performance in the conservation of the mangroves; however, need to outline strategies to conciliate both the biological and cultural conservation.