Relatedness,recognition errors,and colony fusion in the termite <Emphasis Type="Italic">Nasutitermes corniger</Emphasis>

Loss of aggression between social groups can have far-reaching effects on the structure of societies and populations. We tested whether variation in the genetic structure of colonies of the termite Nasutitermes corniger affects the probability of aggression toward non-nestmates and the ability of unrelated colonies to fuse. We determined the genotypes of workers and soldiers from 120 colonies at seven polymorphic microsatellite loci. Twenty-seven colonies contained offspring of multiple founding queens or kings, yielding an average within-colony relatedness of 0.33. Genotypes in the remaining 93 colonies were consistent with reproduction by a single queen and king or their progeny, with an average within-colony relatedness of 0.51. In standardized assays, the probability of aggression between workers and soldiers from different colonies was an increasing function of within-colony relatedness. The probability of aggression was not affected significantly by the degree of relatedness between colonies, which was near zero in all cases, or by whether the colonies were neighbors. To test whether these assays of aggression predict the potential for colony fusion in the field, we transplanted selected nests to new locations. Workers and soldiers from colonies that were mutually tolerant in laboratory assays joined their nests without fighting, but workers and soldiers that were mutually aggressive in the assays initiated massive battles. These results suggest that the presence of multiple unrelated queens or kings promotes recognition errors, which can lead to the formation of more complex colony structures.     

Is reduced clutch size a cost of parental care in Eastern Phoebes (Sayornis phoebe)?

What is the cost of parental care in birds? Previous studies using observational and experimental techniques on nest building and clutch sizes in a small migrant flycatcher, the Eastern Phoebe (Sayornis phoebe), led to contradictory results that did not show a consistent cost of current reproductive effort on residual reproductive output. The data presented here indicate that different elements of parental behaviors are indeed costly because they reduce various aspects of phoebes' subsequent reproductive performance. Experimental removal of old nesting structures at previously used breeding sites reduced but did not eliminate the chance of phoebes' settlement in the subsequent year. Comparing sites at which phoebes did and did not build new nests showed that nest builders completed their first clutches later, had lower probabilities of second breeding attempts, and more often lost their nesting attempt due to fallen nest structures than nest reusers. There was, however, no significant effect of nest building on the clutch sizes and rates of cowbird parasitism of first nesting attempts. Overall, sites with newly built nests had lower seasonal reproductive effort than sites with reused nests. I also examined phoebes' relative residual reproductive output in a separate breeding season when nest building was not experimentally manipulated. When controlled for confounding variables this analysis indicated that in those phoebes that did breed for a second time, the relative decrease of the sizes of first to presumed second clutches was greater at sites where first breeding attempts consisted of more total nestlings. These data are consistent with the hypothesis that parental care is costly in Eastern Phoebes and support predictions of trade-offs between the nest building, brood care, and residual egg-investment components of reproduction.     

Resilience of epilithic algal assemblages in atmospherically and experimentally acidified boreal lakes

Algal assemblages can be highly responsive to environmental changes in recovering acidified lakes. We compared epilithic algal assemblages in boreal lakes during chemical recovery from atmospheric (Killarney Park, Ontario) and experimental (Lake 302S, Experimental Lakes Area, Ontario) acidification to assess the impact of spatial and temporal scale of severe acidification on taxonomic resilience (i.e. recovery rate). Resilience was measured as the distance traveled by lakes in ordination space during pH recovery based on canonical correspondence analysis. Resilience was relatively negligible in the Killarney lakes, suggesting that eight years of experimental acidification in Lake 302S had less impact on biological recovery than did decades of regional acidification. Increases in dissolved organic carbon, dissolved inorganic carbon, and calcium best explained temporal variance of epilithic species abundances in the recovering acidified lakes. In Lake 302S, contrasting trajectories of taxonomic resilience and resistance, i.e. displacement from reference conditions following a perturbation, indicated that ecological factors affecting epilithon differed at corresponding pH levels during recovery and acidification. Our findings reveal that modeling of ecosystem recovery from severe acidification must account for the spatial and temporal scale of the perturbation, and biological delay responses that result in differences between recovery and acidification trajectories.     

Comparison of current Federal Reference Methods for ambient lead measurements adjacent to a secondary lead smelter

The United States Environmental Protection Agency (EPA) reduced their National Ambient Air Quality Standard (NAAQS) for lead (Pb) an order of magnitude to a concentration level of 0.15 micrograms per cubic meter (µg/m³) when the new rule was promulgated in 2008. At that time, the possibility of revising the Pb sampling method from total suspended particulate (TSP) to particulate matter less than or equal to 10 µm in diameter (PM₁₀) was considered due to potential measurement bias of the Pb-TSP monitoring technique. The New York State Department of Environmental Conservation (NYSDEC) has been operating source-orientated colocated TSP and PM₁₀ monitors documenting ambient air lead (Pb) concentrations since 2011 at a site adjacent to a secondary Pb smelter in Wallkill, New York. The colocated Wallkill data show a very strong correlation between the readings recorded by these two sampling techniques. After the range of the variability in the individual Pb-PM₁₀/Pb-TSP ratios was reduced by using a 0.005 µg/m³ concentration cut point, because of the concerns about the measurements at low concentrations, an adjustment factor (AF) of 1.49 was calculated using the remaining data set. This AF can be used to estimate Pb-TSP concentrations from Pb-PM₁₀ readings at this Wallkill source-orientated location. It was stated by the EPA that there is only a limited data set in situations where Pb-TSP and Pb-PM₁₀ are colocated, especially for those sites considered to be source-oriented, so the analyses performed and summarized herein for the Wallkill colocated airborne Pb concentration data add to that limited data set.

Implications: These data analyses add to the limited data set in situations where Pb-TSP and Pb-PM₁₀ are colocated to help refine the derivation of a site-specific adjustment factor for estimating TSP Pb concentrations from measured PM₁₀ Pb concentrations. This could assist the EPA in transitioning away from the use of the Pb-TSP monitoring technique, with its indicated measurement bias, for the Pb NAAQS to the use of Pb-PM₁₀ instead. An adjustment factor of 1.49 was calculated that could be used to estimate Pb-TSP concentrations from Pb-PM₁₀ values collected around this source-orientated location.     

Monitoring and modelling of biosphere/atmosphere exchange of gases and aerosols in Europe

Monitoring and modelling of deposition of air pollutants is essential to develop and evaluate policies to abate the effects related to air pollution and to determine the losses of pollutants from the atmosphere. Techniques for monitoring wet deposition fluxes are widely applied. A recent intercomparison experiment, however, showed that the uncertainty in wet deposition is relatively high, up to 40%, apart from the fact that most samplers are biased because of a dry deposition contribution. Wet deposition amounts to about 80% of the total deposition in Europe with a range of 10-90% and uncertainty should therefore be decreased. During recent years the monitoring of dry deposition has become possible. Three sites have been operational for 5 years. The data are useful for model development, but also for model evaluation and monitoring of progress in policy. Data show a decline in SO(2) dry deposition, whereas nitrogen deposition remained constant. Furthermore, surface affinities for pollutants changed leading to changes in deposition. Deposition models have been further developed and tested with dry deposition measurements and total deposition measurements on forests as derived from throughfall data. The comparison is reasonable given the measurement uncertainties. Progress in ozone surface exchange modelling and monitoring shows that stomatal uptake can be quantified with reasonable accuracy, but external surface uptake yields highest uncertainty.     

Effects of ceiling-mounted HEPA-UV air filters on airborne bacteria concentrations in an indoor therapy pool building

The purpose of this study was to assess the effectiveness of a new generation of high-volume, ceiling-mounted high-efficiency particulate air (HEPA)-ultraviolet (UV) air filters (HUVAFs) for their ability to remove or inactivate bacterial aerosol. In an environmentally controlled full-scale laboratory chamber (87 m3), and an indoor therapy pool building, the mitigation ability of air filters was assessed by comparing concentrations of total bacteria, culturable bacteria, and airborne endotoxin with and without the air filters operating under otherwise similar conditions. Controlled chamber tests with pure cultures of aerosolized Mycobacterium parafortuitum cells showed that the HUVAF unit tested provided an equivalent air-exchange rate of 11 hr(-1). Using this equivalent air-exchange rate as a design basis, three HUVAFs were installed in an indoor therapy pool building for bioaerosol mitigation, and their effectiveness was studied over a 2-year period. The HUVAFs reduced concentrations of culturable bacteria by 69 and 80% during monitoring periods executed in respective years. The HUVAFs reduced concentrations of total bacteria by 12 and 76% during the same monitoring period, respectively. Airborne endotoxin concentrations were not affected by the HUVAF operation.     

Variability of parameters measured during the resuspension of sediments with a particle entrainment simulator

The release of contaminants from sediments is an important problem facing environmental managers concerned with issues such as maintenance dredging, habitat restoration and dredge spoil placement. While there are laboratory methods to assess the remobilization of contaminants from resuspended sediments, little is known about how their operating characteristics influence a sediments response to resuspension. In this study, a particle entrainment simulator (PES) for resuspending sediments was evaluated by assessing variability among replicates and over operation time (12 h) for three estuarine sediments. These sediments varied in physical and chemical properties as well as the degree of metal contamination. Results showed that under identical resuspension conditions, there was low variability among sediment replicates. Sediment properties and the degree of metal contamination affected the magnitude and variation in water column parameters and contaminant release. Fine-grained sediments affected water column parameters, which stabilized over several hours of resuspension. While metal concentrations in the aqueous and particulate samples varied throughout operation, variation was highest for Cd and Ni. Compared to other methods used to evaluate the effects of sediment resuspension, the PES has operational advantages such as the ability to monitor water column conditions and resuspend sediment at specified energy levels. Overall, the PES provided reproducible conditions of resuspension effects among sediments varying in composition and contamination, demonstrating its value as a tool to evaluate contaminant mobility.     

Strength development of solidified/stabilized organic waste and optimum treatment design

Artificially contaminated (spiked) natural soils were solidified/stabilized using various combinations of commonly used additives, such as lime, cement, fly ash, activated carbon, and silica fume. The effectiveness of the solidification/stabilization (S/S) processes was evaluated based on experimental findings from compaction testing, unconfined compressive shear strength, and X-ray diffraction (XRD). Correlations of limited reliability between unconfined compressive strength and penetrometer and torvane measurements were derived. Results from XRD experiments indicated that certain organic contaminants (i.e., naphthalene and pyrene) might impact the S/S processes for a given combination of additives. The type and amount of organic contaminants also affected the pozzolanic reactions. Specifically, the absence or small peak intensity of pozzolanic product XRD patterns for a given combination of additives was a good indication that the type and the amount of organic contaminant present inhibited pozzolanic reactions. This phenomenon was tested and confirmed for actual field-contaminated samples.     

Mixed-function oxidase-specific activity in wild and caged speckled sanddabs Citharichthys stigmaeus in Elkhorn Slough, Moss Landing Harbor and nearshore Monterey Bay, California

The goal of this study was to characterize the spatial, seasonal and annual hepatic activities of mixed-function oxidase (MFO) in the speckled sanddab Citharichthys stigmaeus, the most common fish in the Moss Landing area. In addition, techniques to monitor MFO activities in caged speckled sanddabs were developed and tested. Once the relationship between MFO activities in caged and wild fish populations is determined, caged fish could be used to monitor potential hydrocarbon impacts at Moss Landing, or other marine sites. During each of the spatial, seasonal and annual sediment samplings conducted in 1985-1987 as part of a separate hydrocarbon variability study at Moss Landing, 12 wild speckled sanddabs were collected from Moss Landing Harbor, Elkhorn Slough and nearshore Monterey Bay sites. In addition, four locations were chosen for a 14-day field caged fish experiment. The caged fish experiments successfully demonstrated the feasibility of using caged sanddabs as indicators of hydrocarbon exposure. The major source of variability in hepatic aryl hydrocarbon hydroxylase activity in wild speckled sanddabs from the Moss Landing area is due to seasonal rather than site differences. Significant relationships between caged fish MFO response and sediment hydrocarbon concentrations were found. It is possible that caged fish could be used in place of costly sediment sampling and analysis, and provide a more direct method to assess biological impacts. Many of the caging techniques demonstrated in this study can easily be transferred to other benthic flatfish, and other marine and freshwater environments.