Investigation of evaporation and biodegradation of fuel spills in Antarctica: II-extent of natural attenuation at Casey Station

In many temperate regions, fuel and oil spills are sometimes managed simply by allowing natural degradation to occur, while monitoring soils and groundwater to ensure that there is no off-site migration or on-site impact. To critically assess whether this approach is suitable for coastal Antarctic sites, we investigated the extent of evaporation and biodegradation at three old fuel spills at Casey Station. Where the contaminants migrated across frozen ground, probably beneath snow, approximately half the fuel evaporated in the first few months prior to infiltration at the beginning of summer. Once in the ground, however, evaporation rates were negligible. In contrast, minor spills from fuel drums buried in an abandoned waste disposal site did not evaporate to the same extent. Biodegradation within all three spill sites is generally very minor. We conclude that natural attenuation is not a suitable management strategy for fuel-contaminated soils in Antarctic coastal regions.     

Sequential extraction combined with isotope analysis as a tool for the investigation of lead mobilisation in soils: application to organic-rich soils in an upland catchment in Scotland

Sequential extraction (modified BCR procedure) combined with isotope analysis has been investigated as a tool for assessing mobilisation of lead into streams at an upland catchment in NE Scotland. The maximum lead concentrations (up to 110 mg kg(-1) in air-dried soil) occurred not at the surface but at about 10 cm depth. The lowest (206)Pb/(207)Pb ratios in any profile occurred, with one exception, at 2.5-5 cm depth. In the one exception, closest to the only road in the area, significantly lower (206)Pb/(207)Pb ratios in the surface soil together with much increased chloride concentrations (in comparison to other surface waters) indicated the possible mobilisation of roadside lead and transfer to the stream. The (206)Pb/(207)Pb ratios in extractable fractions tended at depth towards the ratio measured in the residual phase but the ratios in the oxidizable fraction increased to a value higher than that of the residual phase.     

Paradigmatic differences, power, and status: a qualitative investigation of faculty in one interdisciplinary research collaboration on sustainability science

Interdisciplinary research collaborations are fraught with challenges, including the need to overcome paradigmatic differences. The current study sought to understand how 25 faculty members involved in an interdisciplinary endeavor related to sustainability experienced these differences. Using Biglan’s classification and Becher and Trowler’s conceptualizations, the study found issues related to disciplinary status and hierarchy between the soft and hard scientists involved in the project.     

Cavum veli interpositi: prenatal diagnosis and postnatal outcome

We describe the finding of cavum veli interpositi (CVI) on fetal ultrasound and MRI and the postnatal MRI and developmental follow-up in two cases. The first case was diagnosed on fetal ultrasound at 33 weeks' gestation and confirmed on fetal MRI. No abnormalities were detected on postnatal examinations and the brain MRI at 1 year of age showed no changes. At 4 years of age, his growth and development were normal. The second case was diagnosed with CVI on fetal ultrasound and MRI at 33.5 weeks' gestation. Postnatal examination showed no abnormalities, and brain MRI at 8 months of age revealed that the CVI was unchanged, but there was a dilated cavum septum pellucidum and cavum vergae. Her growth and development during the first 4 years of life were normal. CVI is a rare fetal ultrasound finding, which seems to be benign. However, further neurodevelopmental follow-up is needed to confirm this observation. Copyright © 2005 John Wiley & Sons, Ltd.     

Leatherback turtles as oceanographic indicators: stable isotope analyses reveal a trophic dichotomy between ocean basins

Oceanographic sampling is often limited to local and temporally concise assessments of complex, transient, and widespread phenomena. However, long-lived, migratory pelagic vertebrates such as leatherback turtles (Dermochelys coriacea, Vandelli 1761) can provide important integrated information about broad-scale oceanographic processes. Therefore, the present study analyzed stable carbon and nitrogen isotope ratios (δ¹³C and δ¹⁵N) of egg yolk and red blood cells from nesting leatherback populations from Costa Rica in the eastern Pacific in 2003–2004 and 2004–2005 and from St. Croix in the North Atlantic in 2004 and 2005 to establish differences between nutrient sourcing and its influence on higher trophic level consumers in both ocean basins. Whereas δ¹³C signatures were similar between Costa Rica (−19.1±0.7‰) and St. Croix (−19.4±1.0‰) leatherbacks, reflecting the pelagic foraging strategy of the species, Costa Rica leatherback δ¹⁵N signatures (15.4±1.8‰) were significantly enriched relative to St. Croix leatherback δ¹⁵N signatures (9.8±1.5‰). This δ¹⁵N difference likely reflects inter-basin differences in nitrogen cycling regimes and their influence on primary productivity being transferred through several trophic levels. Thus, high-order marine consumer movements, habitat preferences, and stable isotope signatures can be combined with ocean sampling to elucidate interactions between oceanographic processes and marine megafauna.Electronic Supplementary Material Supplementary material is available for this article at and is accessible for authorized users.     

Analysis of PFAAs in American alligators part 2: Potential dietary exposure of South Carolina hunters from recreationally harvested alligator meat

Exposure to perfluorinated alkyl acids (PFAAs) has been linked to many harmful health effects including reproductive disorders, developmental delays, and altered liver and kidney function. Most human exposure to environmental contaminants, including PFAAs, occurs through consumption of contaminated food or drinking water. This study uses PFAA data from meat samples collected from recreationally harvested American alligators (Alligator mississippiensis) in South Carolina to assess potential dietary exposure of hunters and their families to PFAAs. Consumption patterns were investigated using intercept surveys of 23 hunters at a wild game meat processor. An exposure scenario using the average consumption frequency, portion size, and median perfluorooctane sulfonic acid (PFOS) concentration in alligator meat from all hunt units found the daily dietary exposure to be 2.11 ng/kg body weight per day for an adult human. Dietary PFOS exposure scenarios based on location of harvest suggested the highest daily exposure occurs with alligator meat from the Middle Coastal hunt unit in South Carolina. Although no samples were found to exceed the recommended threshold for no consumption of PFOS found in Minnesota state guidelines, exposure to a mixture of PFAAs found in alligator meat and site-specific exposures based on harvest location should be considered in determining an appropriate guideline for vulnerable populations potentially exposed to PFAAs through consumption of wild alligator meat.     

Modeling fecundity in birds: Conceptual overview, current models, and considerations for future developments

Fecundity is fundamental to the fitness, population dynamics, conservation, and management of birds. For all the efforts made to measure fecundity or its surrogates over the past century of avian research, it is still mismeasured, misrepresented, and misunderstood. Fundamentally, these problems arise because of partial observability of underlying processes such as renesting, multiple brooding, and temporary emigration. Over the last several decades, various analytical approaches have been developed to estimate fecundity from incomplete and biased data. These, include scalar arithmetic formulae, partial differential equations, individual-based simulations, and Markov chain methodology. In this paper, we: (1) identify component processes of avian reproduction; (2) review existing methods for modeling fecundity; (3) place these diverse models under a common conceptual framework; (4) describe the parameterization, validation, and limitations of such models; and (5) point out future considerations and challenges in the application of fecundity models. We hope this synthesis of existing literature will help direct researchers toward the most appropriate methods to assess avian reproductive success for answering questions in evolutionary ecology, natural history, population dynamics, reproductive toxicology, and management.