Changes in water level,land use,and hydrological budget in a semi-permanent playa lake,Southwest Spain

Medina playa lake, a Ramsar site in western Andalusia, is a brackish lowland lake of 120 ha with an average depth of 1 m. Water flows into Medina from its 1,748-ha watershed, but the hydrology of the lake has not previously been studied. This paper describes the application of a water budget model on a monthly scale over a 6-year period, based on a conceptual hydrological model, and considers different future scenarios after calibration to improve the understanding of the lake’s hydrological functioning. Climatic variables from a nearby weather station and observational data (water-level evolution) were used to develop the model. Comparison of measured and predicted values demonstrated that each model component provided a reasonable output with a realistic interaction among the components. The model was then used to explore the potential consequences of land-use changes. Irrigation of olive groves would significantly reduce both the hydroperiod (becoming dry 15% of the time) and the average depth of the lake (water level <0.5 m 40% of the time). On the other hand, removal of an artificial overflow would double the average flooded surface area during high-water periods. The simulated water balance demonstrates that the catchment outputs are dominated by lake evaporation and surface outflow from the lake system to a creek. Discrepancies between predicted and observed water levels identify key areas of uncertainty for future empirical research. The study provides an improved basis for future hydrological management of the catchment and demonstrates the wider utility of this methodology in simulating this kind of system. This methodology provides a realistic appraisal of potential land-use management practices on a catchment-wide scale and allows predictions of the consequences of climate change.     

Comparison of DNA extraction methodologies used for assessing fungal diversity via ITS sequencing

Traditional methods of assessing fungal exposure have been confounded by a number of limiting variables. The recent utilization of molecular methods such as internal transcribed spacer (ITS) sequencing of ribosomal RNA genes has provided improved insight into the diversity of fungal bioaerosols in indoor, outdoor and occupational environments. However, ITS analyses may also be confounded by a number of methodological limitations. In this study, we have optimized this technology for use in occupational or environmental studies. Three commonly used DNA extraction methodologies (UltraClean Soil kit, High Pure PCR Template kit, and EluQuik/DNeasy kit) were compared in terms of sensitivity and susceptibility to PCR inhibitors in dust for three common fungal bioaerosols, Aspergillus versicolor, Rhizopus microsporus and Wallemia sebi. Environmental dust samples were then studied using each extraction methodology and results were compared to viable culture data. The extraction methods differed in terms of their ability to efficiently extract DNA from particular species of fungi (e.g. Aspergillus versicolor). In addition, the ability to remove PCR inhibitors from dust samples was most effective using the soil DNA extraction kit. The species composition varied greatly between ITS clone libraries generated with the different DNA extraction kits. However, compared to viable culture data, ITS clone libraries included additional fungal species that are incapable of growth on solid culture medium. Collectively, our data indicated that DNA extraction methodologies used in ITS sequencing studies of occupational or environmental dust samples can greatly influence the fungal species that are detected.     

Display rate by male fairy-wrens (Malurus cyaneus) during the fertile period of females has little influence on extra-pair mate choice

Empirical and theoretical studies have only recently begun to examine how females use complex multi-component displays when selecting mates. Superb fairy-wrens are well suited to the study of female choice because females have control over extra-group paternity and cuckold their mates at high rates, while males possess a variety of sexually selected traits. Available evidence suggests that females base their extra-group mate choice on the timing of male moult into breeding plumage or the onset of display. However, males continue to perform elaborate displays throughout the season, and direct most displays to females during their fertile period. We therefore conducted focal observations on fertile females to quantify the frequency of male display and used microsatellite genotyping to compare the role of display rate during the breeding season and the timing of male moult on female mate choice. We show that the addition of data on male display rate does not improve our ability to predict which males obtain extra-group paternity. The timing of male moult into breeding plumage remains the only predictor of male extra-group reproductive success. Nevertheless, we found that males displayed more to females that were unable to select extra-group mates on the basis of the timing of moult or the onset of display. This raises the possibility that there are circumstances when females use display rate to discriminate between potential extra-group sires. Overall this study supports the theoretical prediction that females are more likely to base their mate choice on reliable indicators of male quality such as fixed morphological traits and displays of endurance, in this case an early moult into breeding plumage and the performance of an elaborate display during the winter, than a flexible behavioural trait such as display rate during the breeding season. Received: 26 January 2000 / Revised: 1 August 2000 / Accepted: 26 August 2000     

An Evaluation of Emissions and Control Technologies for the Metal Decorating Process

Data are reported on a number of controlled and uncontrolled sources from various metal decorating operations. Emission levels are related to process variables such as ink coverage, coater speed, sheet size, and applied coating film weight. Results are presented depicting variation of organic emission levels from a coating process line with elapsed process time. For controlled sources employing either catalytic or thermal incineration, conversion efficiencies are reported as a function of temperature. Operational curves are presented for each control system studied indicating the dependence of carbon dioxide, NO_x, and organic output on incineration temperatures.     

Energy Consumption Requirements for Air Pollution Control Equipment at An Iron Foundry

Energy consumption requirements for air pollution control equipment were studied for varying removal efficiency levels at the Tyler Pipe Industries iron foundry in Tyler, Texas, based on plant fuel consumption data, and on field test measurements of cupola carbon monoxide and particulate control equipment. Natural gas consumption for CO removal increased from 0 in 1970 to 25.4% of the plant total in 1976. Operating costs to achieve 85% CO control increased from 0 in 1970 to $1.61/ton metal in 1976. Increasing cupola incinerator temperature from 800° to 1600° F increased CO removal efficiency from 60 to 97%, but also increased natural gas consumption by 150%. Electricity consumption requirements for 95% to 97% particulate control at the foundry increased from 0.1 % of plant total in 1970 to 18.7% in 1976. Electricity consumption for particulate controls increased plant operating costs from 0.004 in 1970 to 1.693 $/ton metal in 1976 as horsepower increased from 20 to 6,272. Cost-benefit methodology is needed to evaluate trade-offs between air pollution control, energy consumption requirements and operating costs of proposed regulations. Total air pollution control system must be considered in enforcing regulations instead of the source to be controlled alone for overall impacts. Need exists for process modifications to enhance energy recovery and development of energy-effective air pollution control equipment.     

Wind Roses for Florida

A three-dimensional Joint frequency distribution (3DJFD) map of Florida is developed based upon wind rose data available for 10 cities. This map may be used in conjunction with the analytic polar coordinate Gaussian Plume Model or conventional dispersion models to calculate the approximate incremental pollution concentration contours associated with an emission source at any site in Florida. Possible means of generalizing the work to other geographic regions, to stack height altitudes, and to incorporate time dependence are discussed.     

Tracking Regional Background in a Haze Attribution Experiment

ABSTRACT

Emissions from distant source areas are often imagined to provide a steady background to the emissions of whatever local sources are being studied. As part of Project MOHAVE in summer 1992, several air mass markers and an injected stack tracer were measured hourly near the Grand Canyon. Observed haze events generally coincided with transients in methylchloroform and water vapor, which we interpret as endemic tags for air from southern California and the subtropics. The results depict a dynamic regional background.     

Use of Project MOHAVE Perfluorocarbon Tracer Data to Evaluate Source and Receptor Models

ABSTRACT

Project MOHAVE was a major monitoring, modeling, and data analysis study whose objectives included the estimation of the contributions of the Mohave Power Project (MPP) and other sources to visibility impairment in the southwestern United States, in particular at Grand Canyon National Park. A major element of Project MOHAVE was the release of perfluorocarbon tracers at MPP and other locations during 50-day summer and 30-day winter intensive study periods. Tracer data (from about 30 locations) were sequestered until several source and receptor models were used to predict tracer concentrations. None of the models was successful in predicting the tracer concentrations; squared correlation coefficients between predicted and measured tracer were all less than 0.2, and most were less than 0.1.     

Application of the Tracer-Aerosol Gradient Interpretive Technique to Sulfur Attribution for the Big Bend Regional Aerosol and Visibility Observational Study

Abstract

A simple data analysis method called the Tracer-Aerosol Gradient Interpretive Technique (TAGIT) is used to attribute particulate S and SO₂ at Big Bend National Park in Texas and nearby areas to local and regional sources. Particulate S at Big Bend is of concern because of its effects on atmospheric visibility. The analysis used particulate S, SO₂ , and perfluorocarbon tracer data from six 6-hr sampling sites in and near Big Bend National Park. The data were collected in support of the Big Bend Regional Aerosol and Visibility Observational (BRAVO) Study; the field portion was conducted from July through October 1999. Perfluorocarbon tracer was released continuously from a tower at Eagle Pass, TX, approximately 25 km northeast of two large coal-fired power plants (Carbon I and II) in Coahuila, Mexico, and approximately 270 km east-southeast of Big Bend National Park.

The perfluorocarbon tracer did not properly represent the location of the emissions from the Carbon power plants for individual 6-hr sampling periods and attributed only 3% of the particulate S and 27% of the SO₂ at the 6-hr sites in and near Big Bend to sources represented by the tracer. An alternative approach using SO₂ to tag “local” sources such as the Carbon plants attributed 10% of the particulate S and 75% of the SO2 at the 6-hr sites to local sources. Based on these two approaches, most of the regional (65–86%) and a small fraction (19–31%) of the local SO₂ was converted to particulate S. The analysis implies that substantial reductions in particulate S at Big Bend National Park cannot be achieved by only reducing emissions from the Carbon power plants; reduction of emissions from many sources over a regional area would be necessary.     

Stress-related ecophysiology of members of the genus Rhodanobacter isolated from a mixed waste contaminated subsurface

• Rhodanobacter spp. are dominant in acidic, high nitrate and metal contaminated sites. • Dominance of Rhodanobacter is likely due to tolerance to low pH and heavy metals. • High organic content increases stress tolerance capacity. • Longer incubation time is critical for accurate assessment of MIC (various stresses). This work examines the physiologic basis of stress tolerance in bacterial strains of the genus Rhodanobacter that dominate in the acidic and highly metal contaminated near-source subsurface zone of the Oak Ridge Integrated Field Research Challenge (ORIFRC) site. Tolerance of R. denitrificans to levels of different stresses were studied in synthetic groundwater medium and R2A broth. Two strains of R. denitrificans, strains 2APBS1^T and 116-2, tolerate low to circumneutral pH (4–8), high Uranium (1 mmol/L), elevated levels of nitrate (400 mmol/L) and high NaCl (2.5%). A combination of physiologic traits, such as growth at low pH, increased growth in the presence of high organics concentration, and tolerance of high concentrations of nitrate, NaCl and heavy metals is likely responsible for dominance of Rhodanobacter at the ORIFRC site. Furthermore, extended incubation times and use of low carbon media, better approximating site groundwater conditions, are critical for accurate determination of stress responses. This study expands knowledge of the ecophysiology of bacteria from the genus Rhodanobacter and identifies methodological approaches necessary for acquiring accurate tolerance data.