Mitochondrial and microsatellite assessment of population structure of South American sea lion (<Emphasis Type="Italic">Otaria flavescens</Emphasis>) in the Southwestern Atlantic Ocean

Several major breeding areas have been defined for the South American sea lion (Otaria flavescens) along the Atlantic Ocean including the Uruguayan and Patagonian coasts. Together with a documented and severe reduction in population sizes caused by commercial hunting in the last century, these areas show opposite population trends. While Patagonian populations are recovering since hunting ceased, Uruguayan populations are declining. In this context, population genetic structure and genetic diversity were studied for the first time with both nuclear (microsatellites) and mitochondrial (control region) markers together. Alternative scenarios were found for both markers. While mitochondrial marker showed geographically structured populations, the nuclear loci showed a lack of geographical structure. These opposite patterns in genetic structure could be explained by female phylopatry and high male dispersion. The reduction in population size caused by commercial hunting did not leave a detectable footprint of bottleneck at the genetic level.     

Saharan dust episodes and pregnancy

Desert dust is one of the natural contributors to atmospheric particulate matter worldwide. Although particulate pollution has been shown to adversely affect pregnancy, the available evidence on the impact of dust episodes on pregnancy is very scarce. The aim of this study was to evaluate the impact of Saharan dust episodes on pregnancy complications (preeclampsia and bacteriuria) and outcomes (birth weight and gestational age at delivery). This study was based on a cohort of births (N = 3565) that occurred in a major university hospital in Barcelona during 2003-2005. To determine Saharan dust episodes, we developed a two-stage approach based on meteorological evidence of the presence of Saharan dust cloud over the region and unusually high levels of particulate levels on the ground while taking account of traffic sources. The associations between the number of Saharan dust episodes during whole pregnancy as well as each pregnancy trimester and pregnancy complications and outcomes were analysed. There were 152 days (out of 838 days) with Saharan dust cloud over the region from which 45 days were determined as episodic days. We did not observe any statistically significant harmful effect of Saharan dust episodes on our included pregnancy complications and outcomes. However, we observed a small but statistically significant increase in gestational age at delivery in association with the number of episodic days during the third trimester and whole pregnancy (0.8 and 0.5 days respectively). Our findings were not suggestive for any adverse effect of Saharan dust episodes on our included pregnancy complications and outcomes.     

Actinides and decay products in selected produce and bioindicators in the vicinity of a uranium plant

Cypress needles collected at the edge of the Malvési uranium facility (SW France) exhibit enhanced activities of actinides and some decay products (uranium, americium, plutonium, (230)Th, (226)Ra) compared to a remote site. These enhanced activities resulted from the release of U via smokestacks and passive release from former artificial ponds located inside the nuclear site. Enhanced activities are also observed in selected produce (wheat, lettuce, fruits) sampled from the edge of the site. However, excess actinides measured in wheat grains in 2007 are inconsistent with the activities and the uranium ratio measured in the soils. This result suggests that the studied annual crops were contaminated mainly through the short-term release of airborne actinides, and that other transfer pathways, such as, uptake through the roots or adhesion of soil particles, were negligible.     

Scaling-up spatially-explicit ecological models using graphics processors

How the properties of ecosystems relate to spatial scale is a prominent topic in current ecosystem research. Despite this, spatially explicit models typically include only a limited range of spatial scales, mostly because of computing limitations. Here, we describe the use of graphics processors to efficiently solve spatially explicit ecological models at large spatial scale using the CUDA language extension. We explain this technique by implementing three classical models of spatial self-organization in ecology: a spiral-wave forming predator-prey model, a model of pattern formation in arid vegetation, and a model of disturbance in mussel beds on rocky shores. Using these models, we show that the solutions of models on large spatial grids can be obtained on graphics processors with up to two orders of magnitude reduction in simulation time relative to normal pc processors. This allows for efficient simulation of very large spatial grids, which is crucial for, for instance, the study of the effect of spatial heterogeneity on the formation of self-organized spatial patterns, thereby facilitating the comparison between theoretical results and empirical data. Finally, we show that large-scale spatial simulations are preferable over repetitions at smaller spatial scales in identifying the presence of scaling relations in spatially self-organized ecosystems. Hence, the study of scaling laws in ecology may benefit significantly from implementation of ecological models on graphics processors.     

Social parasitism of queens and workers in the Cape honeybee (<Emphasis Type="Italic">Apis mellifera capensis</Emphasis>)

Workers of a queenless honeybee colony can requeen the colony by raising a new queen from a young worker brood laid by the old queen. If this process fails, the colony becomes hopelessly queenless and workers activate their ovaries to lay eggs themselves. Laying Cape honeybee workers (Apis mellifera capensis) produce female offspring as an additional pathway for requeening. We tested the frequency of successful requeening in ten hopelessly queenless colonies. DNA genotyping revealed that only 8% of all queens reared in hopelessly queenless colonies were the offspring of native laying worker offspring. The vast majority of queens resulted from parasitic takeovers by foreign queens (27%) and invading parasitic workers (19%). This shows that hopelessly queenless colonies typically die due to parasitic takeovers and that the parasitic laying workers are an important life history strategy more frequently used than in providing a native queen to rescue the colony. Parasitism by foreign queens, which might enter colonies alone or accompanied by only a small worker force is much more frequent than previously considered and constitutes an additional life history strategy in Cape honeybees.     

Influence of americium-241 on the microbial population and biodegradation of organic waste

The present study investigated the influence of ²⁴¹Am on microbial growth and the degradation of organic waste. Leachate samples collected in a lysimeter were periodically analyzed for bacterial growth, under both aerobic and anaerobic conditions. ²⁴¹Am inhibited bacterial growth, and the degradation of organic matter was delayed in comparison with the control. Minimal inhibitory concentration assays and survival curves revealed that it inhibits the growth of Pseudomonas putida F1. The assay also revealed that ²⁴¹Am is more toxic than ²³⁸U, Zn²⁺ and Cd²⁺. This study further led to the finding of four new radionuclide-tolerant bacterial strains: Flavobacterium spp., Pseudomonas gladioli, Chryseobacterium indologenes and Ochrobactrum anthropi. The survival curves of P. gladioli, C. indologenes revealed that these bacteria are resistant to metal as consortia.     

Mass balance in the monitoring of pollutants in tidal rivers of the Guanabara Bay, Rio de Janeiro, Brazil

This study addressed the identification and monitoring of pollution sources of terrestrial origin in rivers (domestic sewage and industrial effluents) and critical fluvial segments in highly polluted environments under tidal influence (mixing marine and continental sources) from Guanabara Bay Basin, Rio de Janeiro, Brazil. The mass balance of contaminants was determined in conditions of continuous flow (low tide) during dry season (lower dilution capability). The results allowed the evaluation of the potential of contaminant mass generation by the different river segments and the estimation of their natural and anthropogenic components. The water quality of Igua?ú and Sarapuí Rivers were evaluated for metals and biochemical oxygen demand. The method gave an excellent response, including the possibility of sources identification and contaminated river segments ranking. The approach also offers fast execution and data interpretation, being highly efficient.     

Oxidative stress in Nile tilapia (Oreochromis niloticus) and armored catfish (Pterygoplichthys anisitsi) exposed to diesel oil

Considering that diesel oil is one of the most common aquatic contaminants, we compare the oxidative stress between two species of fish with different habitats (Pterygoplichthys anisitsi, benthic and Oreochromis niloticus, nektonic) exposed to diesel oil. Malondialdehyde concentrations (MDA) and the activities of ethoxyresorufin-O-deethylase (EROD), glutathione S-transferase (GST), catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase were all analyzed in the fishes' livers and gills after 2 and 7 days of exposure to different concentrations of diesel (0.1 and 0.5 mL/L). In the tilapia, MDA levels and the activities of EROD and GST activity in the liver, as well as MDA levels and the activities of GST and SOD in the gill had statistically significant differences between the treatments and between the times of exposure. For the catfish, the same occurred in the case of MDA, EROD, and SOD in the liver and in CAT and SOD in the gills. There were significant differences in the enzyme activity and lipid peroxidation between the species. Although the activity of most enzymes seemed to be more expressive and responsive to diesel in O. niloticus, diesel oil also caused significant effects on oxidative stress parameters in P. anisitsi, even though this species is benthic and thus has less access to insoluble fractions of diesel oil. Therefore, both species can be used as sentinel organisms in environmental biomonitoring of diesel contamination.     

Assessment and sources of nonaromatic hydrocarbons in surface sediments of three harbors in Santa Catarina State, Brazil

Nonaromatic hydrocarbons and geochemical parameters from 17 sediment?Cwater interface samples were used to assess sources of organic matter in three harbors, located in Santa Catarina State, southern Brazil. The evaluation was based on the molar C/N/P ratios, abundance of resolved nonaromatic hydrocarbons (3.0?C25.9 ??g g^???1), unresolved complex mixture, and two indexes: the carbon preference index (CPI) and the low molecular weight to high molecular weight ratio. The results indicate that the organic matter is predominantly of terrestrial origin (C/N > 10 and CPI > 2). Variations in the total organic carbon from 0.43 to 2.98 mmol g^???1 and total phosphorus from 82.4 to 464.3 ??g g^???1 showed no clear correlation with the silt and clay fractions of the sediments possibly due to anthropogenic input. In contrast to the low level of contamination based on the acyclic hydrocarbon distribution, the results obtained from a series of geologically stable hopanes and steranes reveal the presence of less degradable petroleum derivatives.     

Heat Gain From Thermal Radiation Through Protective Clothing With Different Insulation,Reflectivity and Vapour Permeability

The heat transferred through protective clothing under long wave radiation compared to a reference condition without radiant stress was determined in thermal manikin experiments. The influence of clothing insulation and reflectivity, and the interaction with wind and wet underclothing were considered. Garments with different outer materials and colours and additionally an aluminised reflective suit were combined with different number and types of dry and pre-wetted underwear layers. Under radiant stress, whole body heat loss decreased, i.e., heat gain occurred compared to the reference. This heat gain increased with radiation intensity, and decreased with air velocity and clothing insulation. Except for the reflective outer layer that showed only minimal heat gain over the whole range of radiation intensities, the influence of the outer garments’ material and colour was small with dry clothing. Wetting the underclothing for simulating sweat accumulation, however, caused differing effects with higher heat gain in less permeable garments.