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511.
Maëlle Connan Patrick Mayzaud Guy Duhamel Bo T. Bonnevie Yves Cherel 《Marine Biology》2010,157(10):2303-2316
Fatty acid (FA) and fatty alcohol (FAlc) compositions of both total lipid and neutral lipid fractions were studied for five
myctophid species sampled in Kerguelen waters. Both qualitative and quantitative FA signature analyses were then performed
to investigate their diet over longer time scales than the conventional stomach content analysis. Regarding their lipid class,
FA and FAlc compositions, the five species could be discriminated into two groups: wax-ester-rich species (Electrona antarctica, Krefftichthys anderssoni) characterised by large amounts of monounsaturated FAs (>73% of total FAs) and triacylglycerol-rich species (Electrona carlsbergi, Gymnoscopelus nicholsi, Protomyctophum bolini) with major amounts of saturated and monounsaturated FAs (>29 and >46% of total FAs, respectively). Qualitative and quantitative
FA analyses showed that K. anderssoni mainly preyed upon copepods, E. antarctica upon copepods and more euphausiids and P. bolini and E. carlsbergi mainly upon euphausiids with some copepods, while G. nicholsi had a more diverse diet. This study shows the usefulness of quantitative statistical analysis to determine the diet of Antarctic
and sub-Antarctic predators and stresses the need of increasing the lipid and FA analyses of more zooplanktonic and micro-nektonic
marine species. 相似文献
512.
Patrick Sejkora Mary Jo Kirisits Michael Barrett 《Journal of the American Water Resources Association》2011,47(6):1275-1284
Sejkora, Patrick, Mary Jo Kirisits, and Michael Barrett, 2011. Colonies of Cliff Swallows on Highway Bridges: A Source of Escherichia coli in Surface Waters. Journal of the American Water Resources Association (JAWRA) 47(6):1275–1284. DOI: 10.1111/j.1752‐1688.2011.00566.x Abstract: Animals, such as birds, are a source of fecal indicator bacteria and pathogens in the environment. Our objective was to determine whether a colony of cliff swallows nesting underneath a bridge would yield a measurable increase in fecal indicator bacteria (specifically Escherichia coli) in the underlying creek. When the swallows were absent, dry‐weather concentrations of E. coli upstream and downstream of the bridge (in Austin, Texas) were below the Texas contact recreation criteria. When the swallows were present, dry‐weather geometric‐mean E. coli concentrations increased significantly from upstream (43 most probable number [MPN]/100 ml) to downstream (106 MPN/100 ml) of the bridge. One exceedance and one near‐exceedance of the Texas single‐sample contact recreation criterion were observed during the swallows’ nesting phase. When the swallows were present, the downstream E. coli geometric‐mean concentration in storm events (875 MPN/100 ml) was significantly higher than the upstream concentration (356 MPN/100 ml), suggesting that runoff flushes swallow feces from the ground into the creek. Although the loading of E. coli from cliff swallows nesting under bridges can be significant (e.g., dry‐weather loading of 3.1 × 108 MPN/day/nest), the zoonotic potential of the cliff swallow must be examined to determine the risk to human health from contact recreation in waters contaminated with cliff swallow feces. 相似文献
513.
Grant E. Brown Maud C. O. Ferrari Patrick H. Malka Marie-Anne Oligny Matthew Romano Douglas P. Chivers 《Behavioral ecology and sociobiology》2011,65(6):1267-1276
Under conditions of spatial and/or temporal variability in predation risk, prey organisms often rely on acquired predator
recognition to balance the trade-offs between energy intake and risk avoidance. The question of ‘for how long’ should prey
retain this learned information is poorly understood. Here, we test the hypothesis that the growth rate experienced by prey
should influence the length of the ‘memory window’. In a series of laboratory experiments, we manipulated growth rate of juvenile
rainbow trout and conditioned them to recognize a novel predator cue. We subsequently tested for learned recognition either
24 h or 8 days post-conditioning. Our results suggest that trout with high versus low growth rates did not differ in their
response to learned predator cues when tested 24 h post-conditioning. However, trout on a high growth rate exhibited no response
to the predator cues after 8 days (i.e. did not retain the recognition of the predator odour), whereas trout on a lower growth
rate retained a strong recognition of the predator. Trout that differed in their growth rate only after conditioning did not
differ in their patterns of retention, demonstrating growth rate after learning does not influence retention. Trout of different
initial sizes fed a similar diet (percent body mass per day) showed no difference in retention of the predator cue. Together,
these data suggest that growth rate at the time of conditioning determines the ‘memory window’ of trout. The implications
for threat-sensitive predator avoidance models are described. 相似文献
514.
Martin Brokate Stephen MacCarthy Alexander Pimenov Alexei Pokrovskii Dmitrii Rachinskii 《Environmental Modeling and Assessment》2011,16(4):313-333
Cyclic wetting and drying of soils due to changing weather conditions is characterised by a well-documented hysteresis in
the relationship between the pressure or matric potential and the water content in the soil. Hysteresis manifests itself through
a difference in drying and wetting curves. Its presence suggests that there is dissipation of energy associated with intermittent
wetting and drying of the soil, which can be released in the form of heat. In this paper, we discuss a model for evaluation
of the energy dissipation rate due to soil-moisture hysteresis. The model has three main ingredients: (a) a hysteresis constitutive
relationship between soil-water potential and moisture content in the soil, which is modelled by the Preisach operator; (b)
a lumped form of Darcy’s law assuming that the water flux is proportional to the difference of potentials in the soil and
on its surface; (c) a rainfall term governing the evolution of the outer potential, which is modelled by a periodic forcing
or a Poisson process. We propose a combination of analytic and numerical methods to evaluate the energy dissipation rate and
how it is affected by the variation of rain parameters, such as the frequency of arrivals of rain cells and their shape, intensity
and duration. 相似文献
515.
Spatial variations of human health risk associated with exposure to chlorination by-products occurring in drinking water 总被引:1,自引:0,他引:1
Legay C Rodriguez MJ Sadiq R Sérodes JB Levallois P Proulx F 《Journal of environmental management》2011,92(3):892-901
During disinfection, chlorine reacts with organic matter present in drinking water and forms various undesirable chlorinated by-products (CBPs). This paper describes a study of the spatial variability of human health risk (i.e., cancer effects) from CBP exposure through drinking water in a specific region. The region under study involves nine drinking water distribution systems divided into several zones based on their characteristics. The spatial distribution of cancer risk (CR) was estimated using two years of data (2006-2008) on various CBP species. In this analysis, trihalomethanes (THMs) and haloacetic acids (HAAs) served as surrogates for CBPs. Three possible routes of exposure (i.e., via ingestion, inhalation and dermal contact) were considered for each selected compound. The cancer risk assessment involved estimating a unit risk (R(T)) in each zone of the selected distribution systems. A probabilistic analysis based on Monte Carlo simulations was employed. Risk assessment results showed that cancer risk varied between systems, but also within individual systems. As a result, the population of the same region was not exposed to the same risk associated with CBPs in drinking water. Unacceptable levels (i.e., R(T) > 10(-4)) for the estimated CR were determined for several zones in the studied region. This study demonstrates that a spatial-based analysis performed to represent the spatial distribution of risk estimates can be helpful in identifying suitable risk management strategies. Suggestions for improving the risk analysis procedure are also presented. 相似文献
516.
Plant traits are influenced by herbivore diet selection, but little is known about how traits are affected by different types of herbivores. We related eight traits of 27 subalpine shrub species in South Island, New Zealand, to damage of these shrubs by introduced red deer (Cervus elaphus) and native invertebrate herbivores using phylogenetically explicit modeling. Deer preferentially consumed species that grew quickly, were low in foliar tannins, or had high leaf area per unit mass. However, these traits did not trade off against each other; rather, they could be related to different multivariate defense strategies. Although the proportion of leaves damaged by leaf-chewing invertebrates also increased with stem growth, invertebrates did not damage the same fast growing species as those preferred by deer. Other traits may also be important in determining herbivore preferences, as suggested by the high proportion of variation in herbivory explained by phylogeny. Last, we found that the composition of invertebrate herbivore communities was more similar among closely related shrubs, and consequently, the range of invertebrate-plant associations may change if introduced deer shift plant composition toward slow-growing species. Overall, our results demonstrate the importance of herbivore type and coevolved interactions for the adaptive significance of plant traits. 相似文献
517.
Bundschuh Mirco Zubrod Jochen P. Konschak Marco Baudy Patrick Frombold Bianca Schulz Ralf 《Environmental science and pollution research international》2021,28(36):49550-49558
Environmental Science and Pollution Research - Nanoparticulate titanium dioxide (nTiO2) is frequently applied, raising concerns about potential side effects on the environment. While various... 相似文献
518.
Paul Scholte Olivier Pays Saleh Adam Bertrand Chardonnet Hervé Fritz Jean-Baptiste Mamang Herbert H. T. Prins Pierre-Cyril Renaud Patrick Tadjo Mark Moritz 《Conservation biology》2022,36(2):e13860
When in 2010 the world's governments pledged to increase protected area coverage to 17% of the world's land surface, several Central African countries had already set aside 25% of their northern savannas for conservation. To evaluate the effectiveness of this commitment, we analyzed the results of 68 multispecies surveys conducted in the seven main savanna national parks in Central Africa (1960–2017). We also assembled information on potential drivers of large herbivore population trends (rainfall and number of rangers) and on tourist numbers and revenues. In six out of the seven parks, wild large herbivore populations declined dramatically over time, livestock numbers increased severalfold, and tourism, the pillar under a once thriving local wildlife industry, collapsed. Zakouma National Park (Chad) stood out because its large herbivore populations increased, an increase that was positively correlated with rainfall and number of rangers (a proxy for management inputs). With increasing insecurity and declining revenues, governments find themselves confronted with too few resources to protect vast areas. To deal with this conversation overstretch, we propose to extend the repeatedly promoted solutions––scaled up funding, enhanced management––with a strategic retreat, focusing scarce resources on smaller areas to save wildlife in the Central African savannas. 相似文献
519.
520.
Primary ciliary dyskinesia (PCD), also referred to as immotile-cilia syndrome or Kartagener syndrome, is a group of genetic disorders caused by defective cilia leading to chronic sinupulmonary infection, situs inversus and reduced fertility. Some PCD patients also have cerebral ventriculomegaly or hydrocephalus. We report here two fetuses and one newborn with mild cerebral ventriculomegaly and a suspected and/or confirmed diagnosis of PCD. These cases demonstrate that mild fetal cerebral ventriculomegaly can be a prenatal sonographic marker of PCD, certainly in fetuses with situs inversus or a history of a previous sib with PCD. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献