Sea Turtles in North Carolina Waters

Until the turn of the century the inshore waters of North Carolina harbored populations of sea turtles large enough to support a commercial fishery. Based on a 4- to-5-year record of sighting reports by the public, interviews of recreational fishermen, and records kept by commercial fishermen the waters continue to provide important developmental habitats for loggerhead, green, and Kemp's ridley sea turtles. Leathertback and hawksbill sea turtles infrequently entered the inshore waters. Reports from the public and commercial fishermen indicated that sea turtles were present offshore North Carolina all year and were present in inshore waters April through December. Sea turtles were encountered most frequently in the Atlantic Ocean, but seasonal encounters in some inshore waters, such as Core and Pamlico Sounds, often were greater. In early May large numbers of leatherbacks were sighted in the ocean and moved northward along the beach. Reported sightings of leatherbacks declined markedly by late June. Based on incidental captures by commercial fishermen loggerhead turtles were the most numerous species in Pamlico and Core Sounds (80%), followed by green (15%) and Kemp's ridley sea turtles (5%). Most captured turtles were immature, and all were released alive. The abundance of immature sea turtles in North Carolina inshore waters serves to emphasize that southeast U.S. estuaries are important habitats for these threatened and endangered species. This recognition supported the decision of the U.S. National Marine Fisheries Service to extend the requirement for turtle excluder devices in shrimp trawls to inshore areas during the entire year, full implementation of these requirements was achieved by December 1994.     

Prenatal diagnosis of medium-chain acyl-coenzyme A dehydrogenase deficiency

A fatal case of medium-chain acyl-coenzyme A dehydrogenase deficiency is described in a patient who presented with hypoglycaemia and a gross non-ketotic dicarboxylic aciduria. Cultured skin fibroblasts released ¹⁴CO₂ from [1–¹⁴C] octanoic acid at half the normal rate. Prenatal diagnosis was undertaken in a subsequent pregnancy in which cultured amniotic fluid cells revealed a marked reduction in octanoate oxidation indicative of an affected fetus. The pregnancy was terminated and the diagnosis was confirmed by enzyme analysis of skin fibroblasts taken from the fetus. The high residual octanoate oxidation by affected fibroblasts together with the absence of any characteristic abnormality of amniotic fluid organic acids are a potential limitation to the reliability of this type of prenatal diagnosis.     

Products of biotransformation of polycyclic aromatic hydrocarbons in fishes of the Athabasca/Slave river system,Canada

Concentrations of products of biotransformation of polycyclic aromatic hydrocarbons (PBPAH) were measured in bile of five fishes of nutritional, cultural and ecological relevance from the Athabasca/Slave river system. Samples were collected in Alberta and the Northwest Territories, Canada, during three seasons. As a measure of concentrations of PBPAHs to which fishes are exposed and to gain information on the nature and extent of potential exposures of people or piscivorous wildlife, concentrations of biotransformation products of two- and three-ringed, four-ringed and five-ringed PAHs were measured using synchronous fluorescence spectroscopy. Spatial and seasonal differences were observed with greater concentrations of PBPAHs in samples of bile of fish collected from Fort McKay as well as greater concentrations of PBPAHs in bile of fish collected during summer compared to those collected in other seasons. Overall, PBPAHs were greater in fishes of lower trophic levels and fishes more closely associated with sediments. In particular, goldeye (Hiodon alosoides), consistently contained greater concentrations of all the PBPAHs studied.     

The roles of competition and environmental heterogeneity in the maintenance of behavioral variation and covariation

Many models of selection predict that populations will lose variation in traits that affect fitness. Nonetheless, phenotypic variation is commonly observed in natural populations. We tested the influences of competition and spatial heterogeneity on behavioral variation within and among populations of Merriam's kangaroo rats (Dipodomys merriami) and tested for the differential expression of trait correlations. We found that populations of D. merriami exhibited more aggression at sites with more competition. Contrary to theoretical predictions and empirical results in other systems, the sites with the greatest spatial heterogeneity and highest levels of competition did not exhibit the most behavioral variation among individuals. However, the greatest within-individual behavioral variability in boldness (response to cues of predator presence) was exhibited where spatial heterogeneity was highest. Aggression and boldness of D. merriami were highly repeatable, that is, individuals behaved in a consistent manner over time, and the two behaviors were also highly correlated. Interestingly, the strength of this correlation was greatest where the competitive community was least diverse. These findings add to increasing evidence that natural populations of animals exhibit patterns of behavioral covariance, or personality structure, and suggest that competitive variation may act to erode personality structure.     

Residence time effects on phase transformation of nanosilver in reduced soils

Residence time effects on phase transformation of silver nanoparticles (AgNPs) (15–50 nm, with and without polyvinylpyrrolidone (PVP) coating) were investigated in reducing soils using experimental geochemistry and synchrotron-based x-ray techniques. After 30 days of anaerobic incubation, a substantial fraction of PVP-coated AgNPs (15 nm) were transformed into Ag₂S and or humic acid (HA) complexed Ag(I), whereas only the HA fraction was dominant in uncoated AgNPs (50 nm). Several investigations recently reported that sulfidation of AgNPs to Ag₂S was the predominant mechanism controlling the fate of AgNP in soil–water environments. However, this investigation showed each AgNP underwent particle-specific chemical transformations to different end compounds after 30 days. Considering the small contribution of Ag(I) dissolution from all AgNPs (less than 5 %), we concluded that changes in solid-state chemical speciation of sorbed AgNPs was promoted by particle-specific interactions of NPs in soil chemical constituents, suggesting a critical role of soil absorbents in predicting the fate of AgNPs in terrestrial environments.     

Light-dependent cytotoxicity of fluoranthene: Oxygen-dependent membrane damage

Fluoranthene, in the presence of ultraviolet light (300–400 nm) induces the hemolysis of human erythrocytes. The absence of photohemolysis under anaerobic conditions proves that a photodynamic process is responsible for the light-dependent cytotoxicity.     

Nutrient contribution of leaf litter in urban stormwater

This paper investigates the nutrient contribution from leaf litter in urban waterways, using data from a gross pollutant monitoring programme in a 50 ha catchment in an inner-city suburb of Melbourne, Australia. The data indicate that the potential nutrient contribution of stormwater leaf litter (greater than 5 mm) is about two orders of magnitude smaller than the typical nutrient loads in urban stormwater. The results suggest that removing leaf litter from urban waterways will do little to reduce the total stormwater nutrient load.1998 Academic Press     

Effects of temporary starvation on larvae of the sea star Asterina miniata

Patchy food distribution may force temporary starvation conditions on planktonic larvae. This potential food limitation may affect survivorship, duration of larval period, and post-metamorphic succes. In this study, larvae of the asteroid Asterina miniata were subjected to temporary food deprivation of several durations and at different stages. Developmental effects were documented by quantification of larval stage, total length, time to metamorphosis, initial juvenile radius, range of settling times, and percent survival to metamorphosis. All starved treatments were significantly affected in settling time and most in percent survival. However, larvae starved later in development demonstrated tremendous tolerance of food deprivation (e.g. the total number of settlers in the treatment starved for 28 d was not significantly different from the fed control). Survival was lower in treatments starved earlier in development than those starved later. Food is apparently required until late in larval development to facilitate metamorphosis. The range of settling times was large; for example, the continuously-fed control treatment produced juveniles from Days 58 through 136. Temporary starvation had no effect on initial juvenile radius.     

The effect of wastewater treatment on antibiotic resistance in Escherichia coli and Enterococcus sp.

The effects of wastewater treatment on the proportion of Escherichia coli and Enterococcus sp. resistant to specific antibiotics were investigated at two facilities in Davis County, Utah, one of which received hospital waste. Samples were taken from the influent, effluent before disinfection, and secondary anaerobic sludge digester effluent. There was very little difference in antibiotic resistance among E. coli in the inflow waters of the plants but the plant receiving hospital waste had a significantly higher proportion of antibiotic resistant Enterococcus. The effect of wastewater treatment on antibiotic resistance was more pronounced on enterococci than E. coli. Although some increases in antibiotic resistance were observed, the general trend seemed to be a decrease in resistance, especially in the proportion of multidrug resistant Enterococcus sp.