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61.
Fecundity and survival in relation to resistance to oxidative stress in a free-living bird 总被引:1,自引:0,他引:1
Major life history traits, such as fecundity and survival, have been consistently demonstrated to covary positively in nature, some individuals having more resources than others to allocate to all aspects of their life history. Yet, little is known about which resources (or state variables) may account for such covariation. Reactive oxygen species (ROS) are natural by-products of metabolism and, when ROS production exceeds antioxidant defenses, organisms are exposed to oxidative stress that can have deleterious effects on their fecundity and survival. Using a wild, long-lived bird, the Alpine Swift (Apus melba), we examined whether individual red cell resistance to oxidative stress covaried with fecundity and survival. We found that males that survived to the next breeding season tended to be more resistant to oxidative stress, and females with higher resistance to oxidative stress laid larger clutches. Furthermore, the eggs of females with low resistance to oxidative stress were less likely to hatch than those of females with high resistance to oxidative stress. By swapping entire clutches at clutch completion, we then demonstrated that hatching failure was related to the production of low-quality eggs by females with low resistance to oxidative stress, rather than to inadequate parental care during incubation. Although male and female resistance to oxidative stress covaried with age, the relationships among oxidative stress, survival, and fecundity occurred independently of chronological age. Overall, our study suggests that oxidative stress may play a significant role in shaping fecundity and survival in the wild. It further suggests that the nature of the covariation between resistance to oxidative stress and life history traits is sex specific, high resistance to oxidative stress covarying primarily with fecundity in females and with survival in males. 相似文献
62.
Diane K. Stoecker Jason E. Adolf Allen R. Place Patricia M. Glibert Donald W. Meritt 《Marine Biology》2008,154(1):81-90
The bloom-forming dinoflagellates Prorocentrum minimum and Karlodinium veneficum can have detrimental effects on some marine life, including shellfish, but little is known about their effects on early life
history stages of bivalves. In the Chesapeake Bay region, blooms of these dinoflagellates overlap with the spawning season
of the eastern oyster, Crassostrea virginica. In laboratory experiments, we compared the effects of P. minimum and K. veneficum on the survival and development of embryos and larvae of the eastern oyster. At 104 cells ml−1, P. minimum did not have a negative effect on embryos and larvae in 2-day exposures. The yield of D-hinge larvae was equal to or greater
than in control treatments. At 2 × 104 cells ml−1 (approximately equal biomass to the P. minimum treatment) K. veneficum caused significant mortality to oyster embryos within 1 day and almost no embryos developed into D-hinge larvae. This effect
was not alleviated by the provision of an alternate food source (Isochrysis sp.). Significant mortality was observed when larvae were exposed to K. veneficum at concentrations of 104 cells ml−1 (approximately 5 ng ml−1 of karlotoxin). The K. veneficum cultures used in these experiments were relatively low in toxin content, more toxic strains could be expected to cause mortality
at lower cell concentrations. Survival and maturation of embryos and larvae may be reduced when spawns of the eastern oyster
coincide with high bloom densities of K. veneficum. 相似文献
63.
Christopher J. Williams Patricia J. Heglund 《Environmental and Ecological Statistics》2009,16(4):495-513
Habitat association models are commonly developed for individual animal species using generalized linear modeling methods
such as logistic regression. We considered the issue of grouping species based on their habitat use so that management decisions
can be based on sets of species rather than individual species. This research was motivated by a study of western landbirds
in northern Idaho forests. The method we examined was to separately fit models to each species and to use a generalized Mahalanobis
distance between coefficient vectors to create a distance matrix among species. Clustering methods were used to group species
from the distance matrix, and multidimensional scaling methods were used to visualize the relations among species groups.
Methods were also discussed for evaluating the sensitivity of the conclusions because of outliers or influential data points.
We illustrate these methods with data from the landbird study conducted in northern Idaho. Simulation results are presented
to compare the success of this method to alternative methods using Euclidean distance between coefficient vectors and to methods
that do not use habitat association models. These simulations demonstrate that our Mahalanobis-distance-based method was nearly
always better than Euclidean-distance-based methods or methods not based on habitat association models. The methods used to
develop candidate species groups are easily explained to other scientists and resource managers since they mainly rely on
classical multivariate statistical methods. 相似文献
64.
Patricia C. Henshaw Derek B. Booth 《Journal of the American Water Resources Association》2000,36(6):1219-1236
ABSTRACT: Stream channels are known to change their form as a result of watershed urbanization, but do they restabilize under subsequent conditions of constant urban land use? Streams in seven developed and developing watersheds (drainage areas 5–35 km2) in the Puget Sound lowlands were evaluated for their channel stability and degree of urbanization, using field and historical data. Protocols for determining channel stability by visual assessment, calculated bed mobility at bankfull flows, and resurveyed cross‐sections were compared and yielded nearly identical results. We found that channel restabilization generally does occur within one or two decades of constant watershed land use, but it is not universal. When (or if) an individual stream will restabilize depends on specific hydrologic and geomorphic characteristics of the channel and its watershed; observed stability is not well predicted by simply the magnitude of urban development or the rate of ongoing land‐use change. The tendency for channel restabilization suggests that management efforts focused primarily on maintaining stability, particularly in a still‐urbanizing watershed, may not always be necessary. Yet physical stability alone is not a sufficient condition for a biologically healthy stream, and additional rehabilitation measures will almost certainly be required to restore biological conditions in urban systems. 相似文献
65.
Phosphates for Pb immobilization in soils: a review 总被引:9,自引:0,他引:9
In its soluble ionic forms, lead (Pb) is a toxic element occurring in waters and soils mainly as the result of human activities.
The bioavailability of lead ions can be decreased by complexation with various materials in order to decrease their toxicity.
Pb chemical immobilization using phosphate addition is a widely accepted technique to immobilize Pb from aqueous solution
and contaminated soils. The application of different P amendments cause Pb in soils to shift from forms with high availability
to the most strongly bound Pb fractions. The increase of Pb in the residual or insoluble fraction results from formation of
pyromorphite Pb5(PO4)3X where X = F, Cl, Br, OH, the most stable environmental Pb compounds under a wide range of pH and Eh natural conditions.
Accidental pyromorphite ingestion does not yield bioavailable lead, because pyromorphite is insoluble in the intestinal tract.
Numerous natural and synthetic phosphates materials have been used to immobilize Pb: apatite and hydroxyapatite, biological
apatite, rock phosphate, soluble phosphate fertilizers such as monoammonium phosphate, diammonium phosphate, phosphoric acid,
biosolids rich in P, phosphatic clay and mixtures. The identification of pyromorphite in phosphate amended soils has been
carried out by different non destructive techniques such as X-ray diffraction, scanning electron microscopy coupled with energy
dispersive X-ray spectroscopy, X-ray absorption fine structure, transmission electron microscopy and electron microprobe analysis.
The effectiveness of in situ Pb immobilization has also been evaluated by selective sequential extraction, by the toxicity
leaching procedure and by a physiologically based extraction procedure simulating metal ingestion and gastrointestinal bioavailability
to humans. Efficient Pb immobilization using P amendments requires increasing the solubility of the phosphate phase and of
the Pb species phase by inducing acid conditions. Although phosphorus addition seems to be highly effective, excess P in soil
and its potential effect on eutrophication of surface water, and the possibility of As enhanced leaching remains a concern.
The use of mixed treatments may be a useful strategy to improve their effectiveness in reducing lead phyto- and bioavailability. 相似文献
66.
Cuyler Christine Rowell Janice Adamczewski Jan Anderson Morgan Blake John Bretten Tord Brodeur Vincent Campbell Mitch Checkley Sylvia L. Cluff H. Dean Côté Steeve D. Davison Tracy Dumond Mathieu Ford Barrie Gruzdev Alexander Gunn Anne Jones Patrick Kutz Susan Leclerc Lisa-Marie Mallory Conor Mavrot Fabien Mosbacher Jesper Bruun Okhlopkov Innokentiy Mikhailovich Reynolds Patricia Schmidt Niels Martin Sipko Taras Suitor Mike Tomaselli Matilde Ytrehus Bjørnar 《Ambio》2020,49(3):805-819
Ambio - Muskoxen (Ovibos moschatus) are an integral component of Arctic biodiversity. Given low genetic diversity, their ability to respond to future and rapid Arctic change is unknown, although... 相似文献
67.
Karley Campbell Ilkka Matero Christopher Bellas Thomas Turpin-Jelfs Philipp Anhaus Martin Graeve Francois Fripiat Martyn Tranter Jack Christopher Landy Patricia Sanchez-Baracaldo Eva Leu Christian Katlein C. J Mundy Sren Rysgaard Letizia Tedesco Christian Haas Marcel Nicolaus 《Ambio》2022,51(2):318
Sea ice continues to decline across many regions of the Arctic, with remaining ice becoming increasingly younger and more dynamic. These changes alter the habitats of microbial life that live within the sea ice, which support healthy functioning of the marine ecosystem and provision of resources for human-consumption, in addition to influencing biogeochemical cycles (e.g. air–sea CO2 exchange). With the susceptibility of sea ice ecosystems to climate change, there is a pressing need to fill knowledge gaps surrounding sea ice habitats and their microbial communities. Of fundamental importance to this goal is the development of new methodologies that permit effective study of them. Based on outcomes from the DiatomARCTIC project, this paper integrates existing knowledge with case studies to provide insight on how to best document sea ice microbial communities, which contributes to the sustainable use and protection of Arctic marine and coastal ecosystems in a time of environmental change.Supplementary InformationThe online version contains supplementary material available at 10.1007/s13280-021-01658-z. 相似文献
68.
Goemeone E. J Mogomotsi Patricia K Mogomotsi Reniko Gondo Tshenolo J Madigele 《中国人口.资源与环境(英文版)》2018,16(2):171-180
Cultural heritage does not have direct economic benefits. However, if properly managed it can stimulate social cohesions, improving the environment and have beneficial economic spin offs for the local communities. This paper discusses the role of communities in the formulation of the policies concerning their local environment. It argues that community engagement by policy makers is important in giving legitimacy and ownership of the policies. Furthermore, this paper discusses the potential of cultural heritage in diversifying the economy in Botswana. This paper recommends for the re-assessment of the relationship between the state and local communities which is critical in resuscitating the seemingly ailing community business organizations. In conclusion, it argues for the sustainable management of cultural heritage as a social and economic resource in the next 50 years of Botswana’s independence. 相似文献
69.
Patricia Blanco-Piñeiro M. Pino Díaz-Pereira Aurora Martínez Vidal 《International journal of occupational safety and ergonomics》2018,24(2):316-323
Objective. Bad posture increases the risk that a musician may suffer from musculoskeletal disorders. This study compared posture quality required by different instruments or families of instruments. Methods. Using an ad-hoc postural observation instrument embracing 11 postural variables, four experts evaluated the postures of 100 students attending a Spanish higher conservatory of music. Results. The agreement of the experts’ evaluations was statistically confirmed by a Cohen's κ value between 0.855 and 1.000 and a Kendall value between 0.709 and 1.000 (p?0.001 in all cases). Moreover, χ2 tests revealed significant association between instrument families and seated posture with respect to pelvic attitude, dorsal curvature and head alignment in both sagittal and frontal planes. This analysis also showed an association between instrument families and standing posture with respect to the frontal plane of the axis of gravity, pelvic attitude, head alignment in the frontal plane, the sagittal plane of the shoulders and overall posture. Conclusions. While certain postural defects appear to be common to all families of instruments, others are more characteristic of some families than others. The instrument associated with the best posture quality was the bagpipe, followed by percussion and strings. 相似文献
70.
Anuluxshy Balasubramaniyam Patricia J. Harvey 《Environmental science and pollution research international》2014,21(22):12651-12661
The choice of plant for phytoremediation success requires knowledge of how plants respond to contaminant exposure, especially their roots which are instrumental in supporting rhizosphere activity. In this study, we investigated the responses of plants with different architectures represented by beetroot (Beta vulgaris), a eudicot with a central taproot and many narrower lateral roots, and tall fescue (Festuca arundinacea), a monocot possessing a mass of threadlike fibrous roots to grow in crude oil-treated sand. In this paper, scanning electron microscopy was used to investigate modifications to plant root structure caused by growth in crude oil-contaminated sand. Root structural disorders were evident and included enhanced thickening in the endodermis, increased width of the root cortical zone and smaller diameter of xylem vessels. Inhibition in the rate of root elongation correlated with the increase in cell wall thickening and was dramatically pronounced in beetroot compared to the roots of treated fescue. The latter possessed significantly fewer (p?<?0.001) and significantly shorter (p?<?0.001) root hairs compared to control plants. Possibly, root hairs that absorb the hydrophobic contaminants may prevent contaminant absorption into the main root and concomitant axile root thickening by being sloughed off from roots. Tall fescue exhibited greater root morphological adaptability to growth in crude oil-treated sand than beetroot and, thus, a potential for long-term phytoremediation. 相似文献