Reproductive isolation between Pogonomyrmex rugosus and two lineages with genetic caste determination

Hybrid speciation occurs when combination of two interspecific genomes results in individuals that are of high fitness but reproductively incompatible with the parental species. Although hybrid speciation is a relatively common source of new species in plants, it appears to be a much rarer occurrence in animal taxa. Here we report on reproductive isolation and range overlap between the rough harvester ant Pogonomyrmex rugosus and two lineages with hybrid genotypes (H 1 and H2). Both lineages obligately interbreed and produce genetically distinct queen and worker offspring, a phenomenon referred to as genetic caste determination (GCD). Diploid offspring produced by gametes of the same lineage develop only into queens, whereas diploid offspring derived from gametes of distinct lineages develop into workers. We investigated small-scale patterns of gene flow between the parent and the two H lineages by sampling along an 80-km transect between a pure P. rugosus population and a two-lineage population. Microsatellite and mitochondrial markers both indicated virtually no gene flow between the parent species and either lineage even at sites where parental and H-lineage colonies co-occurred. The geographic ranges of the parental species and the two-lineage population were essentially parapatric, with a surprisingly narrow band of overlap and evidence of spatial structuring even at microgeographic scales within the transition zone. This suggests that ecological competition with the parent species plays a significant role in determining the evolutionary persistence and current distribution of the hybrid lineages and the genetic caste system.     

Linking movement, diving, and habitat to foraging success in a large marine predator

Establishing where and when predators forage is essential to understanding trophic interactions, yet foraging behavior remains poorly understood in large marine carnivores. We investigated the factors leading to foraging success in gray seals (Halichoerus grypus) in the Northwest Atlantic in the first study to use simultaneous deployments of satellite transmitters, time depth recorders, and stomach-temperature loggers on a free-ranging marine mammal. Thirty-two seals were each fitted with the three types of instrumentation; however, complete records from all three instruments were obtained from only 13 individuals, underscoring the difficulty of such a multi-instrument approach. Our goal was to determine the characteristics of diving, habitat, and movement that predict feeding. We linked diving behavior to foraging success at two temporal scales: trips (days) and bouts (hours) to test models of optimal diving, which indicate that feeding can be predicted by time spent at the bottom of a dive. Using an information-theoretic approach, a Generalized Linear Mixed Model with trip duration and accumulated bottom time per day best explained the number of feeding events per trip, whereas the best predictor of the number of feeding events per bout was accumulated bottom time. We then tested whether characteristics of movement were predictive of feeding. Significant predictors of the number of feeding events per trip were angular variance (i.e., path tortuosity) and distance traveled per day. Finally, we integrated measures of diving, movement, and habitat at four temporal scales to determine overall predictors of feeding. At the 3-h scale, mean bottom time and distance traveled were the most important predictors of feeding frequency, whereas at the 6-h and 24-h time scales, distance traveled alone was most important. Bathymetry was the most significant predictor of feeding at the 12-h interval, with feeding more likely to occur at deeper depths. Our findings indicate that several factors predict feeding in gray seals, but predictor variables differ across temporal scales such that environmental variation becomes important at some scales and not others. Overall, our results illustrate the value of simultaneously recording and integrating multiple types of information to better understand the circumstances leading to foraging success.     

Removal of dyes from water using crosslinked aminomethane sulfonic acid based resin

A new polymeric resin with amino sulfonic acid pendant functions has been prepared for the extraction of acidic and basic dyes from water. Beaded polymer supports were prepared by suspension polymerization of vinyl benzyl chloride (0.9 mol) and ethylene glycol dimethacrylate (0.1 mol). The resulting copolymer beads were modified with amino methane sulfonic acid. The dye adsorption capacity of the resin was found as 0.16 g dye/g resin for ramazol black and 0.15 g dye/g resin for crystal violet. The pH depending measurements and dye sorption kinetics of the resin were also investigated.     

Formation of chloroform by aqueous chlorination of organic compounds.

Thirty organic compounds were selected to investigate their chloroform formation characteristics during chlorination with sodium hypochlorite at pH-values 7.0 and 8.0. These experiments were conducted under conditions similar to those applied on the chlorination of raw water. The results indicated that the chloroform concentrations occurred by the all tested compounds was in the ppm range. The maximum levels of chloroform (11-13 mg/l) were determined during the reaction of resorcinol and phloroglucinol at pH-value 8.0.     

Effective biological control of Salvinia molesta in the Senegal River by means of the weevil Cyrtobagous salviniae

The invasion of Salvinia molesta in the Lower Senegal River Delta in Mauritania and Senegal in 1999 posed a serious threat to the socioeconomic conditions of the local people as well as to wetland biodiversity. Eventually, an effective biological control of S. molesta was obtained by means of the weevil Cyrtobagous salviniae, which was introduced in the river in Senegal and Mauritania in May 2000 and in Senegal in April 2001. In October 2001, it became apparent that the weevils were doing a magnificent job. The color of the plants was turning from green to dark-brown or black, and subsequently the plants started to sink to the bottom. Detailed monitoring of the dispersal of C. salviniae in November-December 2001 confirmed the visual observations of the outcome of biological control. In April 2002, it could be concluded that S. molesta was no longer a problem in the Senegal River.     

Mercury photoreduction and photooxidation in lakes: Effects of filtration and dissolved organic carbon concentration

Mercury is a globally distributed, environmental contaminant. Quantifying the retention and loss of mercury is integral for predicting mercury-sensitive ecosystems. There is little information on how dissolved organic carbon(DOC) concentrations and particulates affect mercury photoreaction kinetics in freshwater lakes. To address this knowledge gap,samples were collected from ten lakes in Kejimkujik National Park, Nova Scotia(DOC: 2.6–15.4 mg/L). Filtered(0.2 μm) and unfiltered samples were analysed for gross photoreduction, gross photooxidation, and net reduction rates of mercury using pseudo first-order curves. Unfiltered samples had higher concentrations(p = 0.04) of photoreducible divalent mercury(Hg(II)RED)(mean of 754 ± 253 pg/L) than filtered samples(mean of 482 ± 206 pg/L);however, gross photoreduction and photooxidation rate constants were not significantly different in filtered or unfiltered samples in early summer. DOC was not significantly related to gross photoreduction rate constants in filtered(R~2= 0.43; p = 0.08) and unfiltered(R~2= 0.02; p = 0.71) samples; DOC was also not significantly related to gross photooxidation rate constants in filtered or unfiltered samples. However, DOC was significantly negatively related with Hg(Ⅱ)_(RED) in unfiltered(R2= 0.53; p = 0.04), but not in filtered samples(R~2= 0.04;p = 0.60). These trends indicate that DOC is a factor in determining dissolved mercury photoreduction rates and particles partially control available Hg(Ⅱ)_(RED) in lake water. This research also demonstrates that within these lakes gross photoreduction and photooxidation processes are close to being in balance. Changes to catchment inputs of particulate matter and DOC may alter mercury retention in these lakes and could partially explain observed increases of mercury accumulation in biota.     

Large-Scale Survey of Human Enteroviruses in Wastewater Treatment Plants of a Metropolitan Area of Southern Italy

Human enteroviruses (HEVs) occur in high concentrations in wastewater and can contaminate receiving environmental waters, constituting a major cause of acute waterborne disease worldwide. In this study, we investigated the relative abundance, occurrence, and seasonal distribution of polio and other enteroviruses at three wastewater treatment plants (WWTPs) in Naples, Southern Italy, from January 2010 to December 2014. Influent and effluent samples from the three WWTPs were collected monthly. One hundred and sixty-one of the 731 wastewater samples collected (22.0%) before and after water treatment were CPE positive on RD cells; while no samples were positive on L20B cells from any WWTPs. Among the 140 non-polio enterovirus isolated from inlet sewage, 69.3% were Coxsackieviruses type B and 30.7% were Echoviruses. Among these, CVB3 and CVB5 were most prevalent, followed by CVB4 and Echo6. The twenty-one samples tested after treatment contained 6 CVB4, 5 CVB3, 3 Echo11, and 2 Echo6; while other serotypes were isolated less frequently. Data on viral detection in treated effluents of WWTPs confirmed the potential environmental contamination by HEVs and could be useful to establish standards for policies on wastewater management.     

Pesticide residues in rivers of a Brazilian Rain Forest Reserve: assessing potential concern for effects on aquatic life and human health

Pesticide residues in water, sediment, and fish samples from rivers of a Brazilian Rain Forest Reserve were measured in November 1998, March 1999, and January 2000. Concentrations of the individual pesticides were compared to ecotoxicological benchmarks based on acute toxicity tests, and to regulatory guidelines to determine the potential concern for effects on aquatic life and human health. Pesticides and metabolites were detected at all 7 sites surveyed. Residues of a total of 27 pesticides or metabolites were found in water and/or sediment samples and fish have accumulated some of the most persistent of these residues. Measured concentrations in water and sediment indicated concern for preservation of aquatic fauna. Several pesticides in water were above levels for drinking water recommended by Brazilian and/or European Union authorities, indicating also a concern for human health.     

A Daily Time Series Analysis of StreamWater Phosphorus Concentrations Along an Urban to Forest Gradient

During a 1-year period, we sampled stream water total phosphorus (TP) concentrations daily and soluble reactive phosphorus (SRP) concentrations weekly in four Seattle area streams spanning a gradient of forested to urban-dominated land cover. The objective of this study was to develop time series models describing stream water phosphorus concentration dependence on seasonal variation in stream base flows, short-term flow fluctuations, antecedent flow conditions, and rainfall. Stream water SRP concentrations varied on average by ±18% or ±5.7 μg/L from one week to another, whereas TP varied ±48% or ±32.5 μg/L from one week to another. On average, SRP constituted about 47% of TP. Stream water SRP concentrations followed a simple sine-wave annual cycle with high concentrations during the low-flow summer period and low concentrations during the high-flow winter period in three of the four study sites. These trends are probably due to seasonal variation in the relative contributions of groundwater and subsurface flows to stream flow. In forested Issaquah Creek, SRP concentrations were relatively constant throughout the year except during the fall, when a major salmon spawning run occurred in the stream and SRP concentrations increased markedly. Stream water SRP concentrations were statistically unrelated to short-term flow fluctuations, antecedent flow conditions, or rainfall in each of the study streams. Stream water TP concentrations are highly variable and strongly influenced by short-term flow fluctuations. Each of the processes assessed had statistically significant correlations with TP concentrations, with seasonal base flow being the strongest, followed by antecedent flow conditions, short-term flow fluctuations, and rainfall. Times series models for each individual stream were able to predict ∼70% of the variability in the SRP annual cycle in three of the four streams (r² = 0.57–0.81), whereas individual TP models explained ∼50% of the annual cycle in all streams (r² = 0.39–0.59). Overall, time series models for SRP and TP dynamics explained 82% and 76% of the variability for these variables, respectively. Our results indicate that SRP, the most biologically available and therefore most important phosphorus fraction, has simpler and easier-to-predict seasonal and weekly dynamics.