Effect of diel period and season on seining effort required to detect changes in Lake Erie beach fish assemblages

Using beach seining data from Lake Erie beaches, we examined the effect of diel period and season on two common study objectives considered sensitive to sampling effort: (1) has fish assemblage composition changed between two sampling time periods?, and (2) how many samples are necessary to provide a representative sample of the fish assemblage? Across a range of effect sizes and power levels, sample sizes were estimated for species richness, total fish abundance, round goby (Neogobius melanostomus) abundance and emerald shiner (Notropis atherinoides) abundance. For most sampling periods and effect sizes, several hundred to several thousand seine hauls were estimated to be required for detecting large-scale (e.g. basin-wide) changes in round goby and emerald shiner abundance. Depending on the indicator of interest, night seining (either spring or fall) was interpreted as the most efficient approach. For both seasons, sampling effort beyond 40 to 50 night seine hauls results in few additional species being detected. Both species accumulation curves and estimated sample sizes indicate that less effort is required to detect species richness changes than fish abundance. For most effect sizes and power levels, estimates of the number of seine hauls required to detect changes in fish abundance are unrealistically large for most monitoring programs. More practical monitoring strategies could be achieved by adopting alternative indicators (e.g. guilds), a more liberal significance level (p=0.1), a paired-site sampling design, or including reference sites.     

What do qualitative rapid assessment collections of macroinvertebrates represent? A comparison with extensive quantitative sampling

It is a fundamental tenet of Rapid Biological Assessments (RBA) that the samples collected reflect the community from which they are drawn. As with any biological sampling, RBA collections are subject to sampling error resulting in the omission of some taxa. The aim of this study is to compare the composition of RBA samples with an estimate of community structure based on extensive quantitative sampling. We used logistic regression to explore the relationships between the frequency of a taxon being collected in an RBA sample and its biological and ecological traits, namely its abundance, distribution, body size and habit. RBA samples and quantitative estimates of community structure were made in riffles in the Kangaroo and Nepean Rivers, New South Wales, Australia. Single RBA samples may collect up to 63% of the taxa that are collected by extensive quantitative sampling at a site. The frequency of a taxon being recorded in an RBA sample was significantly and positively related to all traits tested indicating a bias in the collection methods towards large, abundant and widely distributed taxa. Accordingly, taxa missed by RBA sampling were generally small, narrowly distributed or rare. These findings enhance our understanding of what RBA samples represent, and the bias and source of errors associated with RBA sampling. This study also quantifies the utility of RBA methods for biodiversity assessment.     

How effective has the Clean Water Act been at reducing pollutant mass emissions to the Southern California Bight over the past 35 years?

The Clean Water Act (CWA) has regulated discharges of contaminants since 1972. However, evaluations of the CWA's effectiveness at improving regional water quality are lacking, primarily because integration of monitoring data from multiple dischargers to assess cumulative effects is not required. A rare opportunity exists to assess CWA effectiveness by integrating mass emissions data from all major sources of contaminants to the Southern California Bight from 1971 to 2000. While the coastal population grew by 56% and total effluent volume increased 31% since 1971, mass emissions of nearly all constituents decreased since passage of the CWA, most by greater than 65%. Publicly owned treatment works were the dominant point source of many contaminants, but also accounted for the greatest reductions in pollutant discharge since 1971. As point source treatment has improved, the relative contribution of non-point sources, such as storm water runoff has increased. Despite the increased importance of storm water discharges, regional monitoring and data compilation of this source is lacking, making it difficult to accurately assess trends in non-point source discharge.     

An appraisal of changes in seasonal water quality during passage through a shallow reservoir in Western Poland

Following restoration changes in Antoninek Reservoir physico-chemical and biological processes in the water column and bottom sediments were measured to outline mechanisms of changes in nitrogen, phosphorus and organic matter concentrations during water flow through this reservoir. Intensive mineralisation of organic matter in the shallow sediments stimulated primary production and influenced increasing ammonia and nitrite nitrogen concentrations. Two main factors affected concentrations of phosphorus: (1) its presence in the external loads of river waters entering the reservoir, more important in the colder seasons as the water discharge was higher and (2) from the internal loads coming from bottom sediments. The quality of the river water during its flow through this reservoir improved for most parameters and seasons. However, concentrations of nutrients were still high in waters flowing out from the reservoir and in some months they were higher in the outflow than in waters entering the reservoir.     

Statistical Analysis of Air Pollutants and Meteorological Parameters in Afyon, Turkey

In this study, the relation between sulfur dioxide (SO₂) and particulate matter (PM) concentrations periodically measured in the city of Afyon’s atmosphere with meteorological factors such as precipitation, humidity, temperature, wind velocity, and inversion were investigated. The mean values of SO₂ and PM concentrations measured during the winter months of October–March 1990–1999 were correlated with the meteorological parameters of the same period. Simple and multiple linear regression analysis were utilized to evaluate the contribution of meteorological variables. The statistical results show that the pollutants, i.e., SO₂ and PM are dependent upon humidity, temperature, and inversion at the 1% significance level; while the dependence of both pollutants with temperature is negative when those of humidity and inversion are positive. Two models in which temperature and inversion are dependent with multiple variables are recommended for predicting the contribution of meteorological parameters on SO₂ and PM. In addition, the relationship between humidity, temperature, and inversion with pollutants is also determined using nonlinear (polynomial) models.     

Trace metal levels in Prochilodus lineatus collected from the La Plata River, Argentina

Most of the industrial, urban and sewage discharges are released into the La Plata River, Argentina without any previous treatment. However, few works have investigated the extent of metal contamination. The aim of this study was to assess the levels of cadmium, copper, lead and zinc in liver and gills of adults Prochilodus lineatus collected from three sampling stations along the coast of the La Plata River: Berazategui, Berisso and Atalaya (from north to south). Samplings were performed during 2002 and 2004. Berazategui and Berisso were located nearby the main ducts that discharge the urban and domestic waste disposal from the cities of Buenos Aires and La Plata, respectively. The third station, Atalaya, was free of sewage discharges. Levels of cadmium and copper in liver were always higher than those found in gills. Instead, for lead and zinc, high levels were observed either in liver or gills, depending on the sampling station and the sampling period. In both tissues, the concentrations of metals did not differ significantly between male and female fish. In liver samples, the concentrations of cadmium, copper and zinc tended to increase from north to south. Instead, the levels of lead followed an opposite pattern. No clear tendencies were observed in gill samples. The data may be useful as reference levels of metal contaminants in P. lineatus, the most important fish species in the La Plata River system.     

Mold spore penetration through wall service outlets: a pilot study

A pilot study was conducted to estimate fungal spore penetration for wall service outlets subjected to a constant air pressure. During the laboratory experiment, a wall chamber was fabricated, and telephone, electrical, and cable service outlets were installed. Penicillium chrysogenum spores were aerosolized into the chamber that was held under pressure. Spores that penetrated the outlets were funneled into an impinger for microscopic enumeration. Thirty trials were conducted for each of the five outlets (N?= 150), and the wall chamber was decontaminated between trials. Results of an analysis of variance suggest wall service outlets allow spore penetration. The penetration factor for the telephone outlet was significantly greater than all other outlets (p?< 0.05), and there was no difference in penetration between electrical outlets with and without plugs. Penetration factor differences were attributed to air leakage rates across the outlets. Due to the experimental design and equipment limitations, further research is needed to support these findings.     

Polycyclic aromatic hydrocarbon contamination in stormwater detention pond sediments in coastal South Carolina

The purpose of this study was to characterize the polycyclic aromatic hydrocarbon (PAH) contamination in the sediments of stormwater detention ponds in coastal South Carolina. Levels of the sum of PAH analytes were significantly higher in the sediments of commercial ponds compared to that of reference, golf course, low-density residential, and high-density residential ponds. Isomer ratio analysis suggested that the predominant source of PAHs were pyrogenic; however, many ponds had a PAH signature consistent with mixed uncombusted and combusted PAH sources. PAH levels in these sediments could be modeled using both pond drainage area and pond surface area. These results demonstrate that the sediment from most commercial ponds, and a few residential and golf course ponds, were moderately contaminated with PAHs. PAH levels in these contaminated ponds exceeded between 42% and 75% of the ecological screening values for individual PAH analytes established by US EPA Region IV, suggesting that they may pose a toxicological risk to wildlife.     

Use of preserved museum fish to evaluate historical and current mercury contamination in fish from two rivers in Oklahoma, USA

We examined the effects of a commonly used preservation technique on mercury concentration in fish tissue. After fixing fish muscle tissue in formalin followed by preservation in isopropanol, we found that mercury concentration in fish muscle tissue increased by 18%, reaching an asymptote after 40 days. We used formalin–isopropanol-preserved longear sunfish (Lepomis megalotis) from the Sam Noble Oklahoma Museum of Natural History to examine historical changes and predict current mercury concentrations in fish from two rivers in southeastern Oklahoma. Glover River was free-flowing, while Mountain Fork River was impounded in 1970 and a coldwater trout fishery was established upstream from the collection site in 1989. Mercury concentrations in longear sunfish from Glover River showed no historical changes from 1963 to 2001. Mercury concentrations in longear sunfish from Mountain Fork River showed no change from 1925 to 1993 but declined significantly from 1993 to 2003. We also compared mercury concentrations of the most recently collected longear sunfish in the museum to mercury concentrations of unpreserved fish collected from the rivers in 2006. Concentrations of mercury in museum fish were not significantly different from mercury concentrations in unpreserved fish we collected from the rivers. Our study indicates that preserved museum fish specimens can be used to evaluate historical changes and predict current levels of mercury contamination in fish.     

Investigating Jacaranda mimosifolia tree as biomonitor of atmospheric trace metals

Studies on the use of tree bark as biomonitors for environmental pollutants are still very scarce. We evaluated the reliability of using Jacaranda mimosifolia, a common tree in Tshwane City of South Africa, as a suitable biomonitor of atmospheric trace metals. Bark samples were collected from ten different locations during two sampling periods. The concentrations of the metals were determined by inductively coupled plasma mass spectrometry. The concentrations of the metals were 33.2–1,795 μg/g (Pb), 21.4–210 μg/g (Cu), 68.4–490 μg/g (Zn), 30.6–2,916 μg/g (Cr), 0.12–1.34 μg/g (Cd), and 6.04–68.0 μg/g (V), respectively. The differences obtained for the results from different sites were significant (p?< 0.05). A significant difference was also observed between the two sampling periods. The trace metals concentrations suggested that automobile emissions are a major source of these metals. The study also confirms the suitability of J. mimosifolia as a biomonitor of atmospheric deposition of these metals.