The role of the peregrine falcon (Falco peregrinus) as a bioindicator for the accumulation of organohalogen compounds and other persistent organic pollutants has been established in field studies. Biometric indices for damage caused by pollutants such as the shell thickness and the shell index were determined and the egg contents were analyzed for various pollutants by gas chromatography/mass spectrometry. A wide range of chemically activated luciferase expression (CALUX®) bioassays were performed on subsamples of the eggs.
The following organohalogen compounds were found in the eggs of 2009: dichlorodiphenyltrichloroethane (DDT) and dichlorodiphenyldichloroethane, heptachlor epoxide, hexachlorobenzene, dieldrin, hexachlorocyclohexane, polychlorobiphenyls and polychlorodibenzodioxins and polychlorodibenzofurans, polybromodiphenyl ethers, hexabromocyclododecane, tetrabromobisphenyl A, perfluoro compounds, and mercury. The DDT metabolite, dichlorodiphenyldichloroethene (DDE) (11,800 ng/g dry matter), was found to be the most highly concentrated egg contaminant followed by 2,2′,4,4′,5,5′-hexachlorobiphenyl (3800 ng/g). After a past general drop in pollution level, most egg contaminants presently plateau at levels that may still exceed limit values in foods of animal origin (DDE) or even toxicological thresholds (polychlorobiphenyls + polychlorodibenzodioxins, polybromodiphenyl ethers, perfluorooctanesulfonate, methylmercury).
Accumulation of DDE could be shown in peregrine falcon eggs from the uplands of Southwest Germany with elevations up to 1500 m, presumably due to its global distribution and its cold condensation in higher altitudes. In contrast, the concentration of polychlorobiphenyls in falcon eggs decreases with elevation, indicating that these pollutants originate mainly from conurbations and local industrial sites.
Significant negative correlations were found between both shell index and thickness and the concentration of Hg. A deleterious effect is also evident from a no-observed-adverse-effect level of 120 ng MeHg per gram egg determined by other authors in chronic feeding studies with ibises, which resulted in decreased egg productivity and male homosexual nesting and courtship behavior. The average Hg concentration in the peregrine falcon eggs from 2009 is almost four times higher than this level. MeHg accounted for 82.5% of the Hg present in the eggs of 2009 and 2010.
The cell test DR CALUX® for screening of dioxin-like activities can be used to detect not only the 29 regulated dioxin-like substances but also many other persistent organic pollutants with dioxin-like potencies, such as mixed halogenated dioxins/biphenyls. In our case, the results of bioanalytical screening methods showed no additional effect of other compounds with dioxin-like activity.
Ninety-three out of 177 analytes sought could be detected in the eggs. Chlorinated paraffins, organotin compounds, some pesticides that are still in use, and phthalic esters with the exception of traces of diethylhexyl phthalate could be excluded. All pollutants found in the eggs belong to substance classes banned by the Stockholm and Minamata Conventions. 相似文献
The sea anemone Entacmaea quadricolor simultaneously harbours multiple symbiont types from the genus Symbiodinium, while providing essential habitat for anemonefish. This anemone lives close to its upper thermal threshold and experiences bleaching under elevated temperature and light stress. Here, we determine whether E. quadricolor experienced a shuffling in the abundance of two genetically distinct symbiont types (Symbiodinium C25 and C3.25) during bleaching and recovery. Anemones were exposed to control (22.9 °C) or elevated temperature (28.5 °C) for 42 days, whereas for the following 75 days, all anemones were exposed to 22.9 °C. By day 47, a more pronounced bleaching occurred via symbiont expulsion in the elevated temperature treatment than the control, and the proportion of C25 to C25 + C3.25 increased by 6.2 and 13.2 % in the control and bleached anemones, respectively. The increased relative abundance of C25 to C3.25 after exposure to thermal stress may indicate that C3.25 performs poorly when temperature is elevated. Although no significant recovery in symbiont density was detected, a revival of the C3.25 genotype was found at day 117, which may indicate that it is either more competitive or has qualities that are beneficial to the symbiosis when thermal stress is no longer apparent. This work demonstrates the potential for this anemone species to shuffle its symbiont types in response to environmental change and could provide resilience during times of stress. 相似文献
While our understanding of the early oceanic developmental stage of sea turtles has improved markedly over recent decades, the spatial context for this life history stage remains unknown for Indian Ocean loggerhead turtle populations. To address this gap in our knowledge, 18 juvenile loggerheads were satellite tracked from Reunion Island (21.2°S, 55.3°E) between 2007 and 2011. Nine turtles swam north toward Oman (20.5°N, 58.8°E), where one of the world’s largest rookeries of loggerheads is located. Three individuals traveled south toward South Africa and Madagascar, countries that also host loggerhead nesting grounds. Fourteen of the transmitters relayed diving profiles. A dichotomy between diurnal and nocturnal diving behavior was observed with a larger number of shorter dives occurring during the day. Diving behavior also differed according to movement behavior as individuals spent more time in subsurface waters (between 10 and 20 m) during transit phases. The study provides an understanding of the oceanic movement behavior of juvenile loggerheads in the Indian Ocean that suggests the existence of an atypical trans-equatorial developmental cycle for the species at the ocean basin scale in the Indian Ocean. These results address a significant gap in the understanding of loggerhead oceanic movements and may help with the conservation of the species. 相似文献
Captive bred animals often lack the ability of predator recognition and predation is one of the strongest causes of failure of breed and release projects. Several tadpole and fish species respond defensively to chemical cues from injured or dead conspecifics, often referred to as alarm pheromones. In natural conditions and in species that school, the association of chemical cues from predators to alarm pheromones released by attacked conspecifics may lead to the learning of the predator-related danger without experiencing an attack. In the laboratory, this chemical communication can also be used in associative learning techniques to teach naïve tadpoles to avoid specific predators and improve survivorship of released animals. In our experimental trials, tadpoles of the threatened green and golden bell frog (Litoria aurea) did not avoid or decrease their activity when exposed to solutions of conspecific macerate, suggesting that the chemicals released into the water by dead/injured conspecifics do not function as an alarm pheromone. This non-avoidance of dead conspecific chemicals may explain why green and golden bell frog tadpoles have seemingly not developed any avoidance behaviour to the presence of introduced mosquito fish, and may render attempts to teach naïve tadpoles to avoid this novel predator more difficult. 相似文献
Teleconnections are quasi-periodic changes in atmospheric circulation that oscillate over long periods of time and impact climate over large regions. These patterns are often linked to long-term variations in climate and extreme weather events and may explain regional differences in climate vulnerability. We apply methods of functional data analysis to examine regional impacts of teleconnections on climate in British Columbia, Canada, between 1951 and 2000. We focus on monthly mean temperature as an overall determinant of crop growth and apply functional principal components analysis (FPCA) to study variations in the impacts of four major teleconnection indices affecting the Northern Hemisphere (the Southern Oscillation Index, the Pacific North American (PNA), Pacific Decadal Oscillation, and the North American Oscillation indices). Two challenges we consider are that the impacts of teleconnections cannot be observed directly and that fine scale data required to study regional variations may come from different sources with highly varied records. We first fit thin-plate regression splines to the raw data to construct complete series of pseudo-data at fixed grid points. Regression models incorporating Bayesian P-splines were then fit to the pseudo-data to estimate the impacts of the four teleconnections over time. Finally, FPCA was then applied to study regional variations in these effects. Our analysis identified strong variations in mean temperature associated with the PNA. The resulting spatial patterns also reveal areas of increased/decreased temperature variability that may have higher climate risk or be suitable for expansion of agricultural activity. 相似文献
Risks and futures methods have complementary strengths as tools for managing strategic decisions under uncertainty. When combined, these tools increase organisational competency to evaluate and manage long-term risks, improving the flexibility and agility of the organisation to deal with gross uncertainties. Here, we set out a framework to guide the assessment of strategic risks for long-term business planning, based on its application at Portugal’s largest water utility, Empresa Portuguesa das Águas Livres. Our approach extends strategic risk assessment by incorporating scenario planning—a futures approach used to help the utility move beyond single point forecast of risks to focus on critical dimensions of uncertainty that are fundamental to the resilience of corporate objectives and their vulnerability to external pressures. We demonstrate how we combine two complementary approaches—risk and futures—and use them to assess (i) how a set of baseline strategic risks for a water utility evolves under alternative futures, (ii) the aggregate corporate-level risk exposure, and (iii) the process and responses needed to manage multiple, interdependent strategic risks. The framework offers a corporate approach to evolving strategic risks and improves a utility’s (i) knowledge of uncertainties, (ii) ability to assess the impacts of external developments over long time horizons and the consequences of actions and (iii) degree of flexibility to adapt to possible future challenges. The framework supports risk managers in their long-term strategic planning, through the appraisal and management of multiple, interdependent long-term strategic risks and can be replicated in other organisational contexts to bridge operational and corporate perspectives of enterprise risk.
A life cycle assessment (LCA) focused on biochar and bioenergy generation was performed for three thermal treatment configurations (slow pyrolysis, fast pyrolysis and gasification). Ten UK biodegradable wastes or residues were considered as feedstocks in this study. Carbon (equivalent) abatement (CA) and electricity production indicators were calculated. Slow pyrolysis systems offer the best performance in terms of CA, with net results varying from 0.07 to 1.25tonnes of CO(2)eq.t(-1) of feedstock treated. On the other hand, gasification achieves the best electricity generation outputs, with results varying around 0.9MWhet(-1) of feedstock. Moreover, selection of a common waste treatment practice as the reference scenario in an LCA has to be undertaken carefully as this will have a key influence upon the CA performance of pyrolysis or gasification biochar systems (P/GBS). Results suggest that P/GBS could produce important environmental benefits in terms of CA, but several potential pollution issues arising from contaminants in the biochar have to be addressed before biochar and bioenergy production from biodegradable waste can become common practice. 相似文献
A common theme in recent landscape studies is the comparison of riparian and watershed land use as predictors of stream health.
The objective of this study was to compare the performance of reach-scale habitat and remotely assessed watershed-scale habitat
as predictors of stream health over varying spatial extents. Stream health was measured with scores on a fish index of biotic
integrity (IBI) using data from 95 stream reaches in the Eastern Corn Belt Plain (ECBP) ecoregion of Indiana. Watersheds hierarchically
nested within the ecoregion were used to regroup sampling locations to represent varying spatial extents. Reach habitat was
represented by metrics of a qualitative habitat evaluation index, whereas watershed variables were represented by riparian
forest, geomorphology, and hydrologic indices. The importance of reach- versus watershed-scale variables was measured by multiple
regression model adjusted-R2 and best subset comparisons in the general linear statistical framework. Watershed models had adjusted-R2 ranging from 0.25 to 0.93 and reach models had adjusted-R2 ranging from 0.09 to 0.86. Better-fitting models were associated with smaller spatial extents. Watershed models explained
about 15% more variation in IBI scores than reach models on average. Variety of surficial geology contributed to decline in
model predictive power. Results should be interpreted bearing in mind that reach habitat was qualitatively measured and only
fish assemblages were used to measure stream health. Riparian forest and length-slope (LS) factor were the most important
watershed-scale variables and mostly positively correlated with IBI scores, whereas substrate and riffle-pool quality were
the important reach-scale variables in the ECBP. 相似文献