Seasonal changes in the diet of a critically endangered seabird and the importance of trawling discards

Pelagic seabirds obtain food from oceans where the availability of their prey changes rapidly both seasonally and spatially. Here, we investigated changes in the trophic habits of the critically endangered Balearic shearwater (Puffinus mauretanicus) through the breeding season and tested for dietary differences between sexes and age classes. We analysed δ¹⁵N and δ¹³C values in blood of adults during the pre-incubation, incubation and chick-rearing periods and of their chicks. Using a two-isotope mixing model, we estimated dietary contributions based on isotope values from potential prey species which included small pelagic species available naturally and demersal fish species available only from trawling discards. Balearic shearwaters showed clear isotopic and dietary variation through the breeding season. During pre-incubation, breeding adults appeared to exploit demersal fish, whereas during the incubation and chick-rearing period, they fed mainly on pelagic anchovies (Engraulis encrasicolus) and pilchards (Sardina pilchardus). Similarly, chicks were fed mainly with anchovies, a resource with a high energetic value. This variation in the dietary habits of adult shearwaters during the breeding season was probably related to both natural and fishery-induced seasonal changes in the availability of potential prey species within their main feeding grounds. However, changes in the nutritional requirements of the shearwaters could also play an important role. Indeed, diet differed between sexes during pre-incubation: females fed less on trawling discards and more on small pelagic fish than males. This sexual segregation in diet could be the consequence of higher nutritional requirements of females during this period. Our study reveals the differential importance of both trawling discards and small pelagic fish species for a pelagic seabird depending on the breeding period and illustrates the importance of considering the entire breeding season when making inferences about the importance of specific prey in seabird dietary studies.     

Use of biological monitoring in the assessment of effects of mining wastes on aquatic ecosystems of the alligator rivers region,tropical Northern Australia

The primary objective of the biological monitoring program of the ARRRI is to develop techniques and procedures to monitor and assess effects of the mining and processing of ores on aquatic ecosystems of the Region. Studies have been made in a seasonal tributary (Magela Creek) of the East Alligator River near the Ranger Uranium Mine, and in the upper South Alligator River (SAR) near the Coronation Hill gold, platinum and palladium prospect. Ranger and Coronation Hill are enclosed by Kakadu National Park, environmental safeguards for which require the minimization of impairment of water quality in the aquatic ecosystems. Present studies on Magela Creek are designed to verify the adequacy of release standards, based on biological tests, in protecting the aquatic environment during and after releases of waste-water from Ranger during the Wet season. Detection of short-term effects will be sought by either creekside orin situ monitoring methods. The detection and assessment of any longer-term impacts, however, will rely chiefly on comparisons of post-release data with those of historical baselines. Such baseline information is provided by studies on the structure of macroinvertebrate and fish communities and/or on concentrations of elements in organisms in those communities, in Magela Creek and SAR catchments.     

Community business: a new role for the planner

The growing political pressure for local authorities in the UK to be seen to be doing something about unemployment has led to a variety of local economic initiatives. This paper looks at one such initiative in Scotland. Community Business aims to help those who have not benefitted from conventional schemes; that is, the long‐term unemployed with outdated skills, or with no skills at all. The paper considers how and why planners should be involved in community business promotion, on the basis of Scottish experience.     

Renewable Cellulose Derived Carbon Nanospheres as Nucleating Agents for Polylactide and Polypropylene

Nucleation of polylactide and polypropylene using novel renewable resource biobased carbon nanospheres (CNS) is investigated using differential scanning calorimetry and polarized optical microscopy. Isothermal studies near the optimal crystallization temperature demonstrate at least a five-fold increase in crystallization rate in PP but only a 1.4 times faster crystallization in PLA. Non-isothermal studies reveal an asymptotic relationship of the maximum crystallization temperature with increasing CNS weight loading in PP and no relationship in PLA. Microscopy indicates some aggregation in the solution blended samples and that average spherulite size is reduced 10-fold due to faster nucleation in the composites as compared to the neat polymer. The fractional crystallinity achieved during non-isothermal crystallization increases by about 7% with addition of a small amount of CNS and decreases with weight loading higher than 1%. The crystallization rates obtained in polypropylene are competitive with widely used mineral talc nucleating agents.     

An exposure assessment for selected pharmaceuticals within a watershed in Southern Ontario

Recent studies from a number of countries have shown that measurable concentrations of both human and veterinary pharmaceuticals can be found in a variety of environmental matrices such as surface and ground water, soils, and sediments. Few data are available that characterize the sources, exposure and effects of pharmaceuticals in the environment and there is clearly a need to define these parameters within a Canadian context. We present in this paper the first report in southern Ontario, Canada on the geographic and temporal distribution of pharmaceuticals detected within seven tributaries receiving primarily agricultural inputs in a typical watershed. Of the 28 pharmaceuticals surveyed, 14 were detected in the streams sampled (n=125). Temporal trends in concentration for five frequently detected pharmaceuticals show pulses occurring between May and November of 2003 at similar but varying times over the seasons, depending on the pharmaceuticals, flow rate, and precipitation. Fluctuations in concentration of ions indicative of agricultural run off, such as nitrate and phosphate, were not found to be useful predictors of changes in pharmaceutical concentration (P>0.4), however a significant correlation between dissolved organic carbon and monensin and carbamazepine concentrations were observed (P<0.013). Exposure profiles illustrating concentration distributions for three of the more prevalent pharmaceuticals detected, including lincomycin, monensin and carbamazepine, showed a log normal distribution, useful for calculating centiles of environmental concentrations. While distributions of estimated total potency of pharmaceuticals detected in the surface waters suggested small risks of environmental effects of mixtures to daphnia, green algae, Lemna gibba, and fish, the significance of non-target effects and impacts due to chronic low level exposures to chemical mixtures remains unclear.     

Criteria to determine likelihood of brain injury during explosive events

The occurrence of blast-induced brain injury in individuals serving in Iraq and Afghanistan is dramatically higher than in past conflicts. This has been attributed in part to the prevalence of roadside improvised explosive devices, or IEDs. There is a call from the military medical community to reduce the reliance on victim self-reporting as the primary diagnosis technique to determine the likelihood of brain injury after a blast. This study demonstrates the ability to establish criteria which correlates easily measured parameters to the probability of cerebral contusion and, thus, brain injury. Computational fluid dynamics (CFD) is used to establish the environment from a full range of threats. This is combined with bond graph modeling of varying levels of fidelity to estimate the dynamics of the skull and brain. Results clearly show that a boundary exists in the threat parameter space that determines whether brain injury is probable.     

Forest to reclaimed mine land use change leads to altered ecosystem structure and function.

The United States' use of coal results in many environmental alterations. In the Appalachian coal belt region, one widespread alteration is conversion of forest to reclaimed mineland. The goal of this study was to quantify the changes to ecosystem structure and function associated with a conversion from forest to reclaimed mine grassland by comparing a small watershed containing a 15-year-old reclaimed mine with a forested, reference watershed in western Maryland. Major differences were apparent between the two watersheds in terms of biogeochemistry. Total C, N, and P pools were all substantially lower at the mined site, mainly due to the removal of woody biomass but also, in the case of P, to reductions in soil pools. Mineral soil C, N, and P pools were 96%, 79%, and 69% of native soils, respectively. Although annual runoff from the watersheds was similar, the mined watershed exhibited taller, narrower storm peaks as a result of a higher soil bulk density and decreased infiltration rates. Stream export of N was much lower in the mined watershed due to lower net nitrification rates and nitrate concentrations in soil. However, stream export of sediment and P and summer stream temperature were much higher. Stream leaf decomposition was reduced and macroinvertebrate community structure was altered as a result of these changes to the stream environment. This land use change leads to substantial, long-term changes in ecosystem capital and function.     

Dispositional affectivity as a predictor of work attitudes and job performance

Previous research has shown that dispositional negative affect (NA) is associated with lower levels of job satisfaction. Little research has been conducted, however, on other organizational implications of negative affect or on the potential effects of dispositional positive affect (PA). The present studies examined the relationship of both positive and negative affectivity to organizational commitment, turnover intentions, global job satisfaction and performance. In the first study both NA and PA were associated with organizational commitment and turnover intentions. Additionally, commitment mediated the relationship between dispositional affectivity and turnover. Finally, PA and tenure interacted to predict job performance, such that PA and job performance were positively related, but only for high tenure employees. In Study 2 the findings were generally similar, but not identical. Both NA and PA were related to global job satisfaction and turnover intentions. However, only PA was related to affective organizational commitment. Moreover, both job satisfaction and affective commitment mediated the relationship between dispositional affectivity and turnover intentions. Finally, unlike Study 1, PA was not related to job performance. Rather, NA and tenure interacted such that when individuals were lower in tenure, NA was negatively related to performance.