Nitrogen and carbon flows through Belandur lake - Role of Bellandur lake as a natural wetland treating Bangalore wastewater

Much of the Bangalore sewage is treated in three streams namely Bellandur (K&C Valley),Vrishabhavati and Hebbal-Nagavara stream systems. Among these it is estimated that out of a total of about 500MLD of partially treated sewage is let into the Bellandur tank. We estimate that a total of about 77t N non-industrial anthropogenic nitrogen efflux (mainly urine and excreta) in Bangalore city. This is distributed between that handled by the three sewage streams, soak-pits and land deposition. About 17-24.5t N enters the Bellandur tank daily. This has been happening over few decades and our observations suggest that this approximately 380ha tank is functioning as a C and N removal system with reasonable efficiency. The ammoniacal and nitrate nitrogen content of the water at the discharge points were estimated and found that over 80% of the nitrogen influx and over 75% of the C influx is removed by this tank system. We observed that there are three nitrogen sinks namely bacterial, micro-algal and macrophytes. The micro-algal fraction is dominated by Microcystis and Euglenophyceae members and they appear to constitute a significant fraction. Water hyacinth represents the single largest representative of the macrophytes. This tank has been functioning in this manner for over three decades. We attempt to study this phenomenon from a material balance approach and show that it is functioning with a reasonable degree of satisfaction as a natural wetland. As the population served and concomitant influx into this wetland increases, there is a potential for the system to be overloaded and to collapse. Therefore a better understanding of its function and the need for maintenance is discussed in the paper.

Wetland flora of Uttara Kannada

Uttara Kannada with its luxuriant tropical climate coupled with heavy rainfall harbours a large number of seasonal wetlands, which are inhabited by diverse wetland plants. These wetland plants are of diverse habitats as they may be aquatic, semiaquatic or of moist soils. Different localities were selected throughout the district and studied for their species composition, diversity, richness across different habitats, families, etc. Many wetland plants were found to be endemic and endangered having many economical uses due to their medicinal properties, edibility, etc.

Ecological and socio-economic assessment of Varthur wetland, Bengaluru (India)

Wetlands are the most productive ecosystems, recognized globally for its vital role in sustaining a wide array of biodiversity and provide goods and services. However despite their important role in maintaining the ecology and economy, wetlands in India are endangered by inattention and lack of appreciation for their role. Increased anthropogenic activities such as intense agriculture practices, indiscriminate disposal of industrial effluents and sewage wastes have altered the physical, chemical as well as biological integrity of the ecosystem. This has resulted in the ecological degradation, which is evident from the current ecosystem valuation of Varthur wetland. Global valuation of coastal wetland ecosystem shows a total of 14,785/ha US$ annual economic value. An earlier study of relatively pristine wetland in Bangalore shows the value of Rs. 10,435/ha/day while the polluted wetland shows the value of Rs.20/ha/day. In contrast to this, Varthur, a sewage fed wetland has a value of Rs.118.9/ha/day. The pollutants and subsequent contamination of the wetland has telling effects such as disappearance of native species, dominance of invasive exotic species (such as African catfish), in addition to profuse breeding of disease vectors and pathogens. Water quality analysis revealed of high phosphates (4.22-5.76 ppm) level in addition to the enhanced BOD (119-140 ppm) and decreased DO (0-1.06 ppm). The amplified decline of ecosystem goods and services with degradation of water quality necessitates the implementation of sustainable management strategies to recover the lost wetland benefits.

Prediction of Ground Water Levels in the Uplands of a Tropical Coastal Riparian Wetland using Artificial Neural Networks

Artificial Neural Networks (ANNs) have been found to be a robust tool to model many non-linear hydrological processes. The present study aims at evaluating the performance of ANN in simulating and predicting ground water levels in the uplands of a tropical coastal riparian wetland. The study involves comparison of two network architectures, Feed Forward Neural Network (FFNN) and Recurrent Neural Network (RNN) trained under five algorithms namely Levenberg Marquardt algorithm, Resilient Back propagation algorithm, BFGS Quasi Newton algorithm, Scaled Conjugate Gradient algorithm, and Fletcher Reeves Conjugate Gradient algorithm by simulating the water levels in a well in the study area. The study is analyzed in two cases-one with four inputs to the networks and two with eight inputs to the networks. The two networks-five algorithms in both the cases are compared to determine the best performing combination that could simulate and predict the process satisfactorily. Ad Hoc (Trial and Error) method is followed in optimizing network structure in all cases. On the whole, it is noticed from the results that the Artificial Neural Networks have simulated and predicted the water levels in the well with fair accuracy. This is evident from low values of Normalized Root Mean Square Error and Relative Root Mean Square Error and high values of Nash-Sutcliffe Efficiency Index and Correlation Coefficient (which are taken as the performance measures to calibrate the networks) calculated after the analysis. On comparison of ground water levels predicted with those at the observation well, FFNN trained with Fletcher Reeves Conjugate Gradient algorithm taken four inputs has outperformed all other combinations.

Mercury exposure Aasessment in fish and humans from Sundarban Mangrove Wetland of India

Present study had documented total mercury levels in six commonly consumed fish species, and performed across-sectional study on local residents to gauge their intake of fish (via dietary survey) and mercury exposure (via hair biomarker analyses). Mean total mercury content in edible composites of locally-caught fishes (topse, hilsa, mackerel, topse, sardinella, khoira) was low and ranged from 0.01 to 0.11 mu g g(-1) mercury, dry weight. In a cross-sectional study of 58 area residents, the mercury content in hair ranged from 0.25 to 1.23 mu g g(-1), with a mean of 0.65 +/- 0.23 mu g g(-1), Flair mercury level was not influenced by gender, age, or occupation. Mean number of meals consumed per week was 3.1 +/- 1.1, and all participants consumed at least one fish meal per week. When related to fish consumption, a significant positive association was found between number of fish meals consumed per week and hair mercury levels.

Wetland Tracker Data Collection Central Coast (Morro Bay Region)

The goal of this project was to gather information on wetland restoration projects in the Moro Bay, California, region. Data provided to the San Francisco Estuary Institute (SFEI) will be used to enhance a web-based, public access database, the Bay Area Wetland Project Tracker. Wetland Tracker provides information on the location, size, sponsors, habitats, contact persons, and status of included projects. Its website provides an interactive map of planned and completed wetland projects (http://www.wetlandtracker.org). (Document contains 4 pages)

Wetland Habitat Types of the Carmel River Lagoon.

This is a report delivered to California Department of Parks and Recreation. The purpose of this report is to document and describe the presence, location, and general characteristics for each of the wetland types currently found in the lagoon area. Comments are also made on the general use by different fauna. (Document contains 15 pages)

Wetlands and coastal water quality: Should wetland size matter?

Generally, wetlands are thought to perform water purification functions, removing contaminants as water flows through sediment and vegetation. This paradigm was challenged when Grant et al. (2001) reported that Talbert Salt Marsh (Figure 1.) increased fecal indicator bacteria (FIB) output to coastal waters, contributing to poor coastal water quality. Like most southern California wetlands, Talbert Salt Marsh has been severely degraded. It is a small (10 ha), restored wetland, only 1/100th its original size, and located at the base of a highly urbanized watershed. Is it reasonable to expect that this or any severely altered wetland will perform the same water purification benefits as a natural wetland? To determine how a more pristine southern California coastal wetland attenuated bacterial contaminants, we investigated FIB concentrations entering and exiting Carpinteria Salt Marsh (Figure 2.), a 93 ha, moderate-sized, relatively natural wetland.(PDF contains 4 pages)

Effects of landscape gradients on wetland vegetation communities: information for large-scale restoration

Projects of the scope of the restoration of the Florida Everglades require substantial information regarding ecological mechanisms, and these are often poorly understood. We provide critical base knowledge for Everglades restoration by characterizing the existing vegetation communities of an Everglades remnant, describing how present and historic hydrology affect wetland vegetation community composition, and documenting change from communities described in previous studies. Vegetation biomass samples were collected along transects across Water Conservation Area 3A South (3AS).

Fishes of the Lagunas Encadenadas (Province of Buenos Aires, Argentina), a wetland of international importance

The Lagunas Encadenadas form a large endorheic wetland. The system comprises a chain of five main lagoons (Alsina, Chochico, Del Monte, Del Venado, and Epecuen). During two recent collection trips, 13 species of fish were caught. From the collected material and available data in the literature the following points can be made: The fish fauna of this wetland comprises 18 species from 11 families and six orders. Four species (Cyprinus carpio, Hoplias malabaricus, Loricariichthys anus and Parapimelodus valenciennis) are new records for these water bodies. Fish species diversity decreases from east to west, ie from the most freshwater lagoon (Alsina, with 15 species) to the most saline (Epecuen, 1 species). A similar diversity pattern has been found in zooplankton species.

The avifauna of Laguna Llancanelo (Mendoza, Argentina), a South American wetland of international importance

Laguna Llancanelo is a large (40,000 ha), very shallow (less than 3 m deep), inland saline waterbody, located in southern Mendoza, Argentina. A survey of the avifauna was undertaken during 1983 to 1985; field trips were made mostly to the northeastern and central-western sectors of the lagoon, in the months of April, May, September, October and December. Complementary studies were made by an aerial survey and assessments of terrestrial birds in the surroundings of the lagoon. A total of 64 species in 22 families of birds usually associated with aquatic environments were recorded. The best-represented families of aquatic birds in terms of numbers of species were: Anatidae (13 swans, geese, ducks), Scolopacidae (7 sandpipers and other small waders), Ardeidae (6 herons, bitterns, egrets, Podicipedidae (4 grebes), Rallidae (4 rails, coots) and Charadriidae (4 plovers, lapwings). The most abundant nesting birds on the lagoon were: Black-necked swan Cygnus melancoryphus (824), silvery grebe Podiceps occipitalis (202) and black-crowned night heron Nycticorax nycticorax (100).

Management of wetland resources in the lower Mekong Basin: issues and future directions

The Lower Mekong Basin has extensive wetlands and these are being threatened by numerous problems. Most of these problems are interdependent and interact with one another. The lack of an appropriate definition of wetlands applicable to the region, pervasive inefficiencies and chronic lack of funds among riparian governments, and the poor appreciation of the true economic importance of wetlands and its resources are among the most prominent. The current definition, based on the Convention on Wetlands (Ramsar, Iran, 1971), is too broad when compared to the understanding of wetlands as being swamps, marshes and the like, and was developed specifically for wetlands with international importance as waterfowl habitats. Furthermore, wetlands are composed of different types of resources, which require different modes of management. Often, institutional competition, overlapping mandates and sometimes jealousies occur between government departments when they try to assert their authority on a particular wetland resource and use, and put forward their development plans without considering how these may conflict with other wetlands uses. Finally, effective wetland management requires reliable statistics or information on rate of harvest of natural resources such as fish and others, fishing/harvesting methods over time in order to determine the level of exploitation, and the status of the natural resources. This information is needed to identify opportunities for expansion, to establish historical trends, and to determine when management interventions are necessary to protect the resources from being overused by other developments. In order to address these issues, ICLARM - The World Fish Center has launched a project, the aim of objectives of which are described in this paper.

Avaliação da toxicidade aguda do lixiviado tratado pelos processos de wetland e nanofiltração.

No Brasil, o tratamento do lixiviado, proveniente da disposição dos resíduos sólidos urbanos, ainda é um desafio, haja visto que atualmente não há indícios de tratamento economicamente viável que atenda aos padrões de lançamento da legislação brasileira. Além disso, os diversos tipos de efluentes, mesmo quando adequadamente tratados, apresentam níveis residuais de substâncias que podem conferir toxicidade aos mesmos. Devido a isso, tem-se uma preocupação com essas substâncias remanescentes e, sobretudo, com o seu possível potencial tóxico. Diante desse quadro, a incorporação da avaliação da toxicidade no tratamento dos efluentes é de grande importância na proteção dos ambientes aquáticos. É crescente o interesse pela toxicidade como um parâmetro de controle, que, contudo, é ainda pouco regulamentada. Este estudo tem como principal objetivo ampliar o conhecimento sobre o tratamento de lixiviados através da avaliação da toxicidade por meio de ensaios ecotoxicológicos. Foi avaliada a toxicidade aguda do lixiviado do Aterro Metropolitano de Jardim Gramacho, em Duque de Caxias RJ após os processos de tratamento por wetland e nanofiltração utilizando-se dois organismosteste de diferentes níveis tróficos (Aliivibrio fischeri e Daphnia similis). Os ensaios de toxicidade aguda com a bactéria Aliivibrio fischeri apresentaram valores de CE50 (%) na faixa de 11,75 a 96,17 para o afluente do wetland e valores de CE50 (%) na faixa de 21,60 a 86,32 para o efluente do wetland. Tanto para o afluente, quanto para o efluente do wetland, foram obtidos valores de FT ≤ 8. Para o efluente da nanofiltração, dos 6 ensaios de toxicidade aguda com a bactéria Aliivibrio fischeri, com exceção de 1 amostra, não foi observada toxicidade. Para os ensaios de toxicidade com a Daphnia similis foram obtidos valores de CE50 (%) na faixa de 24,15 a 70,71 para o afluente do wetland e valores na faixa de 19,61 a 70,71 para o efluente do wetland.