Measured Water Quality Parameters Research Articles

Fluorescence monitoring at a recycled water treatment plant and associated dual distribution system – Implications for cross-connection detection

Dual distribution systems are becoming increasingly common in greenfield housing developments in Australia for the redistribution of recycled water to households for non-potable use. Within such schemes there exists the potential for cross-connections between recycled and drinking water systems. Due to the high level of recycled water treatment, these events are unlikely to lead to outbreaks of illness in the community. Nonetheless, they do represent a breach of the recycled water risk management strategy and therefore an elevated level of risk to consumers. Furthermore, cross-connection events have the potential to undermine public confidence in these types of water recycling. A rapid, highly sensitive method of cross-connection detection may therefore provide an additional level of confidence in these schemes. The aim of this research was to determine the potential for using fluorescence spectroscopy as a monitoring tool in water treatment plants and dual distribution systems. Samples from both the water recycling plant and dual distribution system were collected on a weekly basis over 12 weeks. Fluorescence excitation–emission matrix (EEM) spectra and water quality parameters including dissolved organic carbon, UV 254, pH, conductivity, free chlorine and turbidity were obtained for each sample. The fluorescence EEM spectra of recycled and drinking water were distinctly different and exhibited low variability throughout the course of the sampling program, indicating a degree of stability of the fluorescent components within the organic matter. A ten-fold difference in mean fluorescence intensity was observed for recycled water compared to drinking water, which was greater than the difference observed for the other measured water quality parameters. Probabilistic analysis was used to determine the reliable detection limit of recycled water contamination of drinking water. Accounting for the inherent variability of both recycled water and drinking water, a 45% contamination of recycled water in drinking water could be detected with a signal-to-noise ratio greater than 3 for more than 95% of individual random sample pairs. Greater sensitivity can be assured by averaging numerous samples. In comparison, a 70% contamination of recycled water in drinking water was required for the same detection using conductivity.

The Efficacy of a Tropical Constructed Wetland for Treating Wastewater During the Dry Season: The Kenyan Experience

Constructed wetlands have recently received considerable attention as low cost and efficient means of cleaning up many different types of wastewaters at secondary and tertiary levels. This is an environmentally sound method of wastewater treatment that does not use hazardous chemicals, and is based on the high productivity and nutrient removal capability of the wetland that strongly relies on its intricate ecosystem structure and function. Research work was conducted on a tropical constructed wetland to establish its capability to treat wastewater during the dry season. A comparison of its efficacy with that of conventional wastewater treatment plants was made on the basis of the measured water quality parameters. Temperature, pH, dissolved oxygen, and conductivity were measured in situ. Total suspended solids (TSS), total dissolved solids (TDS), biochemical oxygen demand (BOD5), chemical oxygen demand (COD), phosphorus, ammonia, and nitrites were analyzed in the laboratory. Fecal coliforms were enumerated and Escherichia coli counts were determined. The TSS values reduced from a mean of 102 mg/l at the influent point to 16 mg/l at the effluent point, depicting a reduction of 84.3%. Influent TDS averaged 847 mg/l, while the effluent averaged 783 mg/l. Dry season BOD5 levels were reduced from an average of 286 at the inlet point to 11 mg/l at the outlet representing a reduction efficiency of 96.2%. COD levels were reduced from a mean of 2,002.5 to 47.5 mg/l depicting a removal efficiency of 97.6%. Phosphorus was reduced from a mean of 14 to 11 mg/l representing a percentage removal of 21.4%. Levels of ammonia reduced from a mean of 61 at the influent point to 36 mg/l at the effluent point representing a percent reduction of 41.0%. There was a 99.99% reduction for both the fecal coliforms and E. coli counts. Conductivity of wastewater increased from 1.08 to 1.98 mS, while the pH increased from 6.23 at the inlet point to 7.99 at the outlet of the system. Temperature and dissolved oxygen measurements showed a diurnal variation. The dry season wastewater heavy metal concentrations were in the following ranges: Pb (0.7–6.9 ppm), Cr (0.2–0.5 ppm), Zn (0.1–2.3 ppm), Ni (0.1–1.3 ppm) with Cd and Cu not being detected in the wastewater streams. Overall, tropical constructed wetlands are effective in treating wastewater streams and they perform a lot better than the popularly used waste stabilization ponds. This paper recommends that they can be widely used within the tropics.

Assessment of hydrochemical quality of ground water under some urban areas within Sana’a secretariat

Groundwater from nine wells of three different districts, located at Sana’a secretariat was analyzed for hydrochemical quality assessment. Measurements of water quality parameters including pH, EC, CO32-, HCO3-,Cl-,NO3-,SO4 2-,Ca2+, Mg2+, Fe3+, K+, and Na+ were carried out . Classification of the groundwater samples according to Cl, SO4 2-, CO32- and HCO3-, hardness (H), total dissolved solids (TDS), base-exchange, and meteoric genesis was demonstrated. Suitability of ground water samples for irrigation and industrial uses according to sodium adsorption ration (SAR), ratio of dissolved sodium (RDS), residual sodium carbonate (RSC) and saturation index (SI) was also investigated. The results of this study showed that almost all ground water samples were of good quality that makes them suitable for drinking and domestic uses. Results also indicated that even though some of the ground water samples were suitable for irrigation purposes, almost all of them were found not be good for industrial uses. Despite all drawbacks of the sewerage system built around Sana’a secretariat at the beginning of the first decade of the third millennium, the results of this study indicate that there is scope of significant improvement in Sana’a secretariat ground water quality.

Occurrence of antibiotic resistance genes in reclaimed water and river water in the Werribee Basin, Australia

The purpose of this study was to investigate the occurrence of antibiotic resistance genes (ARGs) in water used for irrigation in the Werribee River Basin, Australia, including river water and reclaimed effluent water (reclaimed water). Samples of reclaimed water, collected over a one-year period, were screened for the occurrence of ARGs using PCR detection assays. The presence of ARGs in the reclaimed water samples were contrasted with that of water samples taken from the Werribee River Basin, collected over the same time period, from five points selected for varying levels of urban and agricultural impact. Of the 54 river water samples collected, 2 (4%), 2 (4%), 0 and 0 were positive for methicillin, sulfonamide, gentamicin and vancomycin-resistant genes, respectively, while 6 of 11 reclaimed water samples were positive for methicillin (9%) and sulfonamide (45%). The presence/absence of ARGs did not appear to correlate with other measured water quality parameters. The low detection of ARGs in river water indicates that, regardless of its poor quality, the river has not yet been severely contaminated with ARGs. The greater prevalence of ARGs in reclaimed water indicates that this important agricultural water source will need to be monitored into the future.

An Application of Landsat-5TM Image Data for Water Quality Mapping in Lake Beysehir, Turkey

The main goal of this study was to investigate spatial patterns in water quality in Lake Beysehir, which is the largest freshwater reservoir in Turkey, by using Landsat-5TM (Thematic Mapper) data and ground surveys. Suspended sediment (SS), turbidity, Secchi disk depth (SDD), and chlorophyll-a (chl-a) data were collected from 40 sampling stations in August, 2006. Spatial patterns in these parameters were estimated using bivariate and multiple regression (MR) techniques based on Landsat-5TM multispectral data and water quality sampling data. Single TM bands, band ratios, and combinations of TM bands were estimated and correlated with the measured water quality parameters. The best regression models showed that the measured and estimated values of water quality parameters were in good agreement (0.60 < R 2 < 0.71). TM3 provided a significant relationship (R 2 = 0.67, p < 0.0001) with SS concentration. MR between chl-a and various combinations of TM bands showed that TM1, TM2, and TM4 are strongly correlated with measured chl-a concentrations (R 2 = 0.60, p < 0.0001). MR of turbidity showed that TM1, TM2, and TM3 explain 60% (p < 0.0001) of the variance in turbidity. MR of SDD showed a strong relationship with measured SDD, with R 2 = 0.71 (p < 0.0001) for the ratio TM1/TM3 and TM1 band combinations. The spatial distribution maps present apparent spatial variations of selected parameters for the study area covering the largest freshwater lake and drinking water reservoir in Turkey. Interpretation of thematic water quality maps indicated similar spatial distributions for SS, turbidity, and SDD. A large area in the middle portion of the lake showed very low chl-a concentrations as it is far from point and nonpoint sources of incoming nutrients. The trophic state index values were calculated from chl-a and SDD measurements. Lake Beysehir was classified as a mesotrophic or eutrophic lake according to chl-a or SDD parameters, respectively.

Assessment of hydrochemical quality of ground water under some urban areas within sana'a secreteriat

Groundwater from nine wells of three different districts, located at Sana'a secretariat was analyzed for hydrochemical quality assessment. Measurements of water quality parameters including pH, EC, CO32-, HCO3-, Cl-, NO3-, SO42-, Ca2+, Mg2+, Fe3+, K+, and Na+ were carried out . Classification of the groundwater samples according to Cl, SO42-, CO32- and HCO3-, hardness (H), total dissolved solids (TDS), base-exchange, and meteoric genesis was demonstrated. Suitability of ground water samples for irrigation and industrial uses according to sodium adsorption ration (SAR), ratio of dissolved sodium (RDS), residual sodium carbonate (RSC) and saturation index (SI) was also investigated. The results of this study showed that almost all ground water samples were of good quality that makes them suitable for drinking and domestic uses. Results also indicated that even though some of the ground water samples were suitable for irrigation purposes, almost all of them were found not be good for industrial uses. Despite all drawbacks of the sewerage system built around Sana'a secretariat at the beginning of the first decade of the third millennium, the results of this study indicate that there is scope of significant improvement in Sana'a secretariat ground water quality.

Nutrient Transport in Runoff from Feedlots as Affected by Wet Distillers Grain Diet

Distillers byproducts can serve as valuable sources of protein and energy for beef cattle. However, the water quality effects of the use of distillers byproducts in cattle rations are not well understood. The objectives of this study were to: (1) measure soil properties and nutrient transport in runoff from feedlot surfaces as affected by corn-based and wet distillers grain diets, (2) compare the effects of unconsolidated surface materials and consolidated subsurface materials on feedlot soil characteristics and runoff nutrient transport, (3) determine if runoff nutrient transport from feedlot surfaces is correlated to selected feedlot soil properties, and (4) identify the effects of varying runoff rate on nutrient transport. Simulated rainfall events were applied to 0.75 m wide by 2 m long plots. Concentrations of calcium, copper, loss on ignition, magnesium, organic-N, potassium, total N (TN), and zinc in the feedlot soil materials were significantly greater within the pens where cattle were fed a corn-based diet rather than a diet with distillers grain. The pens where cattle were fed distillers grain contained significantly greater amounts of Bray-1 P. Surface condition did not significantly affect any of the measured feedlot soil properties except potassium content. No significant differences in measured runoff water quality parameters were found between the corn-based and wet distillers grain treatments. Runoff measurements of NH4-N, TN, NO3-N, total dissolved solids, and electrical conductivity were each significantly correlated to seven or more feedlot soil parameters. Each of the measured water quality parameters were significantly influenced by runoff rate.

Initial appraisal of water quality of Lake Santa Ana, Mexico

AbstractLake Santa Ana is located in the Mexican central plateau, a semiarid region characterized by low rainfall and high evaporation rates. Because of the area's climatic conditions, most of its few existing lakes and reservoirs are ephemeral, with significantly reduced surface areas during the dry season. Mexican authorities currently pay little or no attention to these special aquatic ecosystems. As a consequence, several of these waterbodies are severely degraded in regard to both water quantity and quality. As a result, this report describes Lake Santa Ana as a case study. Several water quality parameters, including physicochemical, microbiological and heavy metal concentrations, were measured at eight sampling sites in the lake, and four sites in the lake basin, in 2005. Some dissolved ions were also analysed in 2007 in the lake, and in a well located close to the lake, in order to evaluate possible interactions between groundwater and surface waters. These study results indicate that the lake does not have significant interactions with groundwater in the local aquifer. Most of the measured water quality parameters do not meet the international suggested standards for inland surface waters to sustain aquatic life, and preserve the habitat for both endemic and migratory waterfowl. Loss of aquatic habitats puts at risk the value of the central portion of Mexico as a migratory route for North American waterfowl species.

Nutrient and Bacterial Transport in Runoff from Soil and Pond Ash Amended Feedlot Surfaces

The addition of pond ash (fly ash that has been placed in evaporative ponds and subsequently dewatered) to feedlot surfaces provides a healthier environment for livestock and economic advantages for the feedlot operator. However, the water quality effects of pond ash amended surfaces are not well understood. The objectives of this field investigation were to: (1) compare feedlot soil properties, and nutrient and bacterial transport in runoff, from pond ash amended surfaces and soil surfaces; (2) compare the effects of unconsolidated surface materials (USM) (loose manure pack) and consolidated subsurface materials (CSM) (compacted manure and underlying layers) on nutrient and bacterial transport in runoff; and (3) determine if the measured water quality parameters are correlated to soil properties. Simulated rainfall events were applied to 0.75 m wide 2 m long plots with different surface materials and surface conditions. Measurements of calcium, magnesium, sulfur, and pH were found to be significantly greater on the pond ash amended surfaces. In comparison, the soil surfaces contained significantly greater amounts of Bray 1-P. The runoff load of NH4-N was significantly greater on the pond ash amended surfaces, while the total phosphorus (TP) load was significantly greater on the soil surfaces. The NO3-N and total nitrogen (TN) loads in runoff were significantly greater on the feedlot surfaces containing CSM. Concentrations of E. coli in runoff were similar on the pond ash amended surfaces and soil surfaces. The dissolved phosphorus (DP), particulate phosphorus (PP), and TP load of runoff were all significantly correlated to Bray 1-P measurements.

An assessment of quality of water from boreholes in Bindura District, Zimbabwe

This study assessed the water quality of 144 boreholes in Bindura District in Mashonaland Province of Zimbabwe as part of a borehole rehabilitation project implemented by a local NGO. In previous studies it has been observed that some boreholes are not used for domestic purposes because of consumer perceived poor water quality. Consequently, communities have resorted to unsafe alternative water sources thus creating health risks. The study was carried out in June 2005. The objectives of the study were to assess the levels of parameters associated with the aesthetics of the water and to compare them with guideline values for drinking water. The study also investigated the relationship between some of the measured water quality and the consumer perceived water quality. Measured water quality parameters included pH, temperature, electrical conductivity (EC), turbidity, calcium (Ca), magnesium (Mg) and iron (Fe). All parameters were measured in the field except Ca, Mg and Fe, which were measured in a laboratory using a spectrophotometer. Consumer perceptions on water quality were investigated through interviews with the consumer community. Turbidity was found to be 0.75–428(20.8 ± 59.2; n = 144) NTU, pH 5.7–9.3 (6.88 ± 0.46; n = 144), temperature 18–26.8 (22.6 ± 2.1; n = 144) °C. EC 26–546 (199 ± 116; n = 144) μS/cm, Ca 6–71.6 (26.9 ± 14.1; n = 81) mg/l, Mg 1.2–49.6 (12.3 ± 10.0; n = 81) mg/l and Fe 0.08–9.60 (0.56 ± 1.15; n = 81) mg/l. Some 23% of the samples had pH outside the recommended range of 6.5–8.5, whilst 59% of the samples had turbidity values exceeding the 5NTU WHO limit. For EC, all samples had values less than the WHO derived limit of 1380 μS/cm. All Ca and magnesium values were within the common and recommended levels of 100 mg/l and 70 mg/l respectively. Iron had values greater than the WHO and SAZ limit of 0.3 mg/l in 36% of the samples. Water quality was deemed satisfactory for taste and soap consumption by 95% and 72% of the respondents respectively. Satisfaction was higher for drinking compared to soap consumption meaning that generally hard waters may still be acceptable for drinking purposes. The water quality met the stipulated standard or guideline value from a minimum of 41% (turbidity) to a maximum of 100% (EC, Ca and Mg). There was no correlation between taste and conductivity as some 5% of the respondents suggested the water was unsatisfactory although all EC values were far below the maximum limit. Again there was no correlation between iron and taste as iron had 36% of the samples above the threshold of 0.3 mg/l whilst objectionable taste perception was only in 5% of the cases. It is recommended that priority in future projects should be given to repairs of boreholes whose water quality is acceptable according to consumer perceptions obtained at project planning stage. Low cost household treatment aimed at improving quality should be investigated.

Factor Analysis For Water Quality And Quantity of Tigris River At Selected Sites South Mosul City

This research aimed to emphasis Tigris river water quality and quantity variations at two sites: Qaber Al-Abid village downstream Mosul city and Dwezat village after its meeting with the Upper Zab river using factor analysis technique. Weekly samples were collected from the two sites along a year. Samples were tested for pH, electrical conductivity, total alkalinity, total hardness, calcium, magnesium, sodium, potassium, chloride, sulphate, nitrate, phosphate, dissolved oxygen, biochemical oxygen demand, suspended solids, total solids, total dissolved solids, in addition to the discharge of the river. The results of each site were analyzed statistically using factor analysis for each season and for the whole year. Factor analysis concentrated the measured water quality parameters and discharge into two to four factors for seasonal analysis, which represent (90.69%-100%) of the variation in water quality and quantity. On the other hand, five factors were extracted from the yearly data at Qaber Al-Abid site and six factors at Dwezat site.The results of factor analysis revealed that pH, conductivity and PO4- 3 is the highest contributor to the variation in water quality at the two sites. Organic pollution came in the second order in Qaber Al-Abid since it is location downstream of Mosul city, while the effect of Upper Zab made the discharge and sediment load (SS, TS and TDS) in the second order for the variation in Dwezat site.

Prediction of Bromate Formation Using Multi-Linear Regression and Artificial Neural Networks

The main objective of this study was to develop simple models for the prediction of bromate formation in ozonated bottled waters, using rapidly and practically measurable raw water quality and/or operational parameters. A total of 6 multi-linear regression (MLR) with or without principal component analysis (PCA) and 2 artificial neural networks (ANN) models with multilayer perceptron architecture were developed for the prediction of bromate formation. PCA was employed to better identify relations between variables and reduce the number of variables. Experimental data used in modeling was provided from the ozonation of samples from 5 groundwater sources at various applied ozone dose and contact time. MLR models#1 and #2 well-predicted bromate formation although correlations (i.e., the signs of regression constants) among pH (as input variable) and bromate concentrations did not agree with the chemistry. MLR model#6, containing practical input parameters that are measured on-line in full-scale treatment plants, adequately predicted bromate formation and agreed with the chemistry, although fewer input parameters were used compared to MLR#1 and #2. Although both of the ANN models exhibited high regression coefficients (R2) (0.97 for both) ANN#1 was found to provide better prediction of bromate formation based on mean square error (MSE) values. However, since ANN#2 included easily measurable input parameters it may be practically used by water companies employing ozonation. Results overall indicated that ANN models have stronger prediction capabilities of bromate formation than MLR models. ANN modeling appears to be a strong tool in situations where the relations between variables are non-linear, interactive and complex, as in the bromate formation by ozonation.

Use of fuzzy synthetic evaluation for assessment of groundwater quality for drinking usage: a case study of Southern Haryana, India

A method based on concept of fuzzy set theory has been used for decision-making for the assessment of physico-chemical quality of groundwater for drinking purposes. Conventional methods for water quality assessment do not consider the uncertainties involved either in measurement of water quality parameters or in the limits provided by the regulatory bodies. Fuzzy synthetic evaluation model gives the certainty levels for the quality class of the water based on the prescribed limit of various regulatory bodies and opinion of the experts from the field of drinking water quality. In this paper, application of fuzzy rule based optimization model is illustrated with twenty groundwater samples from Sohna town of Gurgaon district of Southern Haryana, India. These samples were analysed for 15 different physico-chemical parameters, out of them nine important parameters were used for the quality assessment using fuzzy synthetic evaluation approach. From this study, it has been concluded that all the water samples are in acceptable category whose certainty level ranges from 44 to 100%. Water from these sources can be used for the drinking purposes if alternate water source is not available without any health concern on the basis of physico-chemical characteristics.

Moderating effects of the geometry of reservoirs on the relation between urban land use and water quality

Edges mediate the material flux between adjacent systems. This mediating effect of edges is strongly tied to the complexity of the adjacent shapes. Land use within a watershed has a direct impact on the water quality of adjacent aquatic systems. Hydrological processes carry material produced by land-use activities into aquatic ecosystems through the edges of the ecosystem. Therefore, the geometry of aquatic ecosystems theoretically affects the relationship between land use and water quality. This study investigates whether the shape complexity of reservoirs moderates the direct impact of land use on the water quality of adjacent reservoirs. A moderation model was adopted to measure the shape effects, and 153 reservoirs were randomly sampled with a consideration of reservoir size (surface area), geographic location, and data availability. With a focus on urban land use, we used GIS to measure land-use types within a 1 km buffer of reservoir boundaries. The shape complexity of sampled reservoirs was measured using fractal dimensions. Land uses and shape complexity were then regressed to measure water quality parameters such as chemical oxygen demand (COD), biological oxygen demand (BOD), total nitrogen (TN) and total phosphorus (TP). Correlation analysis revealed that the shapes of reservoirs are likely to be simple where urban land use dominates the areas close to reservoirs. Use of the standard regression model indicated that the increasing shape complexity of reservoirs significantly reduces the concentration of BOD, COD, and TP within reservoir water. Moderation models for BOD, COD, TN, and TP suggest that shape complexity can considerably relieve the negative impacts on water quality of urban land use in areas adjacent to reservoirs. The results of this study highlight the need to focus on shoreline management in order to mitigate the adverse impacts of land use on lakes and reservoirs.

Evaluation of water quality parameters for the Mamasin dam in Aksaray City in the central Anatolian part of Turkey by means of artificial neural networks

Sustaining the human ecological benefits of surface water requires carefully planned strategies for reducing the cumulative risks posed by diverse human activities. The municipality of Aksaray city plays a key role in developing solutions to surface water management and protection in the central Anatolian part of Turkey. The responsibility to provide drinking water and sewage works, regulate the use of private land and protect public health provides the mandate and authority to take action. The present approach discusses the main sources of contamination and the result of direct wastewater discharges into the Melendiz and Karasu rivers, which recharge the Mamasin dam sites by the use of artificial neural network (ANN) modeling techniques. The present study illustrates the ability to predict and/or approve the output values of previously measured water quality parameters of the recharge and discharge areas at the Mamasin dam site by means of ANN techniques. Using the ANN model is appreciated in such environmental research. Here, the ANN is used for estimating if the field parameters are agreeable to the results of this model or not. The present study simulates a situation in the past by means of ANN. But in case any field measurements of some relative parameters at the outlet point “discharge area” have been missed, it could be possible to predict the approximate output values from the detailed periodical water quality parameters. Because of the high variance and the inherent non-linear relationship of the water quality parameters in time series, it is difficult to produce a reliable model with conventional modeling approaches. In this paper, the ANN modeling technique is used to establish a model for evaluating the change in electrical conductivity (EC) and dissolved oxygen (DO) values in recharge (input) and discharge (output) areas of the dam water under pollution risks. A general ANN modeling scheme is also recommended for the water parameters. The modeling process includes four main stages: (1) source data analysis, (2) system priming, (3) system fine-tuning and (4) model evaluation. Results of the ANN modeling scheme indicate that the output values are agreeable to the water quality parameters, which were measured at the field in the static water mass of the Mamasin dam lake. Water contamination at the dam site is caused by the continuous increase of nutrient contents and decrease of the O2 level in water causing an anaerobic condition. It may stimulate algae growth flow in such water bodies, consequently reducing water quality.

Heat, Chloride, and Specific Conductance as Ground Water Tracers near Streams

Commonly measured water quality parameters were compared to heat as tracers of stream water exchange with ground water. Temperature, specific conductance, and chloride were sampled at various frequencies in the stream and adjacent wells over a 2-year period. Strong seasonal variations in stream water were observed for temperature and specific conductance. In observation wells where the temperature response correlated to stream water, chloride and specific conductance values were similar to stream water values as well, indicating significant stream water exchange with ground water. At sites where ground water temperature fluctuations were negligible, chloride and/or specific conductance values did not correlate to stream water values, indicating that ground water was not significantly influenced by exchange with stream water. Best-fit simulation modeling was performed at two sites to derive temperature-based estimates of hydraulic conductivities of the alluvial sediments between the stream and wells. These estimates were used in solute transport simulations for a comparison of measured and simulated values for chloride and specific conductance. Simulation results showed that hydraulic conductivities vary seasonally and annually. This variability was a result of seasonal changes in temperature-dependent hydraulic conductivity and scouring or clogging of the streambed. Specific conductance fits were good, while chloride data were difficult to fit due to the infrequent (quarterly) stream water chloride measurements during the study period. Combined analyses of temperature, chloride, and specific conductance led to improved quantification of the spatial and temporal variability of stream water exchange with shallow ground water in an alluvial system.

Environmental effects on bacterial diversity in the surface mucus layer of the reef coral Montastraea faveolata

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 328:133-142 (2006) - doi:10.3354/meps328133 Environmental effects on bacterial diversity in the surface mucus layer of the reef coral Montastraea faveolata Reia Guppy*, John C. Bythell Division of Biology, Ridley Building, University of Newcastle, Newcastle upon Tyne NE1 7RU, UK *Email: reia.guppy@ncl.ac.uk ABSTRACT: Spatial and temporal variation in bacterial 16S rDNA diversity from healthy coral Montastraea faveolata (Ellis & Solander, 1786) was investigated using denaturing gradient gel electrophoresis (DGGE). The microbial communities of the surface mucus layer (SML) were investigated at 5 sites in Tobago of varying water quality and proximity to the mainland. Presence/absence and band intensity data from DGGE profiles were used as a relative measure of diversity of the microbial community structure. Multivariate analyses using PRIMER software Version 6.1.5 (multidimensional scaling and analysis of similarity) showed that microbial communities associated with corals from within the same reef area were very similar (p = 0.093), that there were significant differences between sites (p = 0.001), and that SML communities were significantly different from the microbial community within the water column (p = 0.001). No strong correlations between the SML bacterial community structure and measured water quality parameters were observed using a biota-environment matching routine within PRIMER (BIOENV). Strong seasonal effects were observed on tagged corals from sites that were re-sampled 6 times covering the wet and dry seasons. Although the SML of M. faveolata appears to support a distinct microbial community, this study shows that intraspecific temporal and spatial variation also exists, and reasons for these differences are explored. KEY WORDS: Bacterial fingerprinting · 16S rDNA · Denaturing gradient gel electrophoresis · DGGE · Coral mucus · Tobago Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 328. Online publication date: December 20, 2006 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2006 Inter-Research.

Evolution of a man‐made plume in coastal waters

The ability to understand the biogeophysical parameters that create ocean color in coastal waters is fundamental to exploiting remote sensing for coastal applications. The apparent color, which is the upwelling radiance of large water bodies is determined by the absorption and scattering of light caused by the water, the organic and inorganic material contained in the water, and the bottom, when the albedo is high enough and the water is shallow enough.Bio‐optical oceanography measures and models the interaction of the light field with the biological and nonbiological constituents of natural waters. One goal of optical oceanography is to be able to use measured radiance to identify and quantify water constituents, referred to as inherent optical properties (IOPs). Linking optical properties with measured water quality parameters often is made through radiative transfer models, in which the light field is modeled through the water and all of its constituents. This modeling is done to evaluate optical closure, which is the ability to accurately predict the upwelling radiance resulting from a known set of constituents.

Trophic structure and avian communities across a salinity gradient in evaporation ponds of the San Francisco Bay estuary

Commercial salt evaporation ponds comprise a large proportion of baylands adjacent to the San Francisco Bay, a highly urbanized estuary. In the past two centuries, more than 79% of the historic tidal wetlands in this estuary have been lost. Resource management agencies have acquired more than 10 000 ha of commercial salt ponds with plans to undertake one of the largest wetland restoration projects in North America. However, these plans have created debate about the ecological importance of salt ponds for migratory bird communities in western North America. Salt ponds are unique mesohaline (5– 18 g l−1) to hyperhaline (>40 g l−1) wetlands, but little is known of their ecological structure or value. Thus, we studied decommissioned salt ponds in the North Bay of the San Francisco Bay estuary from January 1999 through November 2001. We measured water quality parameters (salinity, DO, pH, temperature), nutrient concentrations, primary productivity, zooplankton, macroinvertebrates, fish, and birds across a range of salinities from 24 to 264 g l−1. Our studies documented how unique limnological characteristics of salt ponds were related to nutrient levels, primary productivity rates, invertebrate biomass and taxa richness, prey fish, and avian predator numbers. Salt ponds were shown to have unique trophic and physical attributes that supported large numbers of migratory birds. Therefore, managers should carefully weigh the benefits of increasing habitat for native tidal marsh species with the costs of losing these unique hypersaline systems.

Monitoring the impact of urbanisation on the Glinscica stream

Stream flow regimes are determined by watershed characteristics: climate, geology, topography, soil, vegetation and human activities. In the process of urbanisation, natural land surfaces are replaced by man made artificial coverage, such as paved roads, parking lots and roofs, which usually also implies vegetation clearing and soil compaction. Gutters, drains and storm sewers are built to accelerate the conveyance of runoff to stream channels, thus affecting the drainage system. The impact of urbanisation is complex and affects different elements of the hydrological cycle. The commonly observed hydrological responses of the watershed to urbanization are increased volume and peak of floodwaters. Concerning the ecological status of stream water, the intensified rainfall runoff induces increased pollution risks and diminishes the value of the stream water body as a habitat, especially during dry periods. In order to improve the flood safety, the regulations of the stream channel have further devaluated the ecological role of the urban streams. The magnitude of the impact is usually enlarged with the decrease in the stream size. The present paper aims at presenting the results of a two-year study monitoring the impacts of the urban environment on the watershed of the Glinscica stream situated in the central part of Slovenia. The study area of 19.3 km 2 represents a great complexity in terms of the land use pattern. The watershed was equipped with three rainfall stations, a Doppler velocity meter and a water quality multiprobe. In a short period of time more than 10 thunderstorm events were recorded and analyzed. The hydrological response of the watershed was analyzed and, interestingly, it did not show the “typical” urban impact on the runoff processes. The main water quality parameters such as temperature, pH, TDS, ORP, conductivity, dissolved oxygen and especially the concentrations of nitrate and ammonium, were measured to obtain an insight into seasonal and short time dynamics of the water quality. The results show substantial seasonal and along-the-channel variations of concentration of dissolved oxygen, nitrate and ammonium content due to biochemical processes in the channeled stream. The continuous tracing of nitrate and ammonium showed significant influence of stream regulation works on short time variations of the measured water quality parameters.