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151.
John T. Wilson Gary D. Miller William C. Ghiorse Franklin R. Leach 《Journal of contaminant hydrology》1986,1(1-2)
The rate of biotransformation of toluene in unconsolidated subsurface material from sites at Lula, Oklahoma, and Conroe, Texas, was compared to the ATP (adenosine triphosphate) content of these materials. The rate of toluene degradation decreased with decreasing ATP content. When ATP contents were at or less than 0.05 ng g−1, biotransformation of toluene could not be detected (less than 1% of the initial concentration was degraded per week). At intermediate concentrations of ATP, 0.37 and 0.16 ngvg−1, the rates of toluene degradation were 18 ± 4.5% and 25 ± 10% of the initial concentration per week. At ATP concentrations above 1 ng g−1, the rates of toluene degradation exceeded 90% of the initial concentration per week. There was no simple relationship between ATP content and chlorobenzene degradation. Subsurface material that had been exposed to creosote wastes, and which degraded toluene rapidly, also degraded benzene, o-xylene, and m-xylene. 相似文献
152.
Measurements of outdoor human exposure to suspended particulate matter (PM) are always constrained by available resources. An effective network design requires tradeoffs between variables measured, the number of sampling locations, sample duration, and sampling frequency. Sampling sites are needed to represent neighborhood and urban spatial scales with minimal influences from nearby sources. Although most PM measurements for determining compliance with standards are taken over 24-h periods every third to sixth day, outdoor human exposure assessment requires measurements taken continuously throughout the day, preferably over durations of 1 h or less. More detailed particle size and chemistry data are also desirable, as smaller size fractions and specific chemicals may be better indicators of adverse health effects than total mass samples. 相似文献
153.
Sanderson H Ingerslev F Brain RA Halling-Sørensen B Bestari JK Wilson CJ Johnson DJ Solomon KR 《Chemosphere》2005,60(5):619-629
A mixture of four tetracyclines; oxytetracycline (OTC), chlortetracycline (CTC), tetracycline (TC), and doxycycline (DC) was applied in fifteen 12000l outdoor microcosms at four treatment levels plus controls each with three replicates (n = 3). The dissipation times of parent compounds were monitored and half-lives (DT50) of 1-4 days, depending on treatment level were recorded. This is in accordance with half-lives from previous findings in bench-top experiments. Parent compound DT50, were determined using HPLC-UV. Furthermore, the samples were analyzed for ten different tetracycline products using LC/MS/MS. Two products were found for chlortetracycline; 4-epi-anh-chlortetracyline and the iso-chlortetracycline. Iso-forms were only found for CTC and only at the highest treatment (300 microg l(-1)). The half-lives, trajectories, and relative amounts of the products were analogous for all four tetracyclines. DT50 for products were less than 1.2 days. Formation of 4-epi-anh-tetracyclines, occurred at neutral to weak alkaline conditions. 相似文献
154.
155.
A new concept based on analysis of dive depth data was developed to help estimate prey consumption in ten free-ranging Magellanic penguins (Spheniscus magellanicus) that were brooding chicks. By simultaneously analysing the undulations in the dive depth profile (measured by time-depth recorders, TDRs) and beak opening (obtained from the recently developed intra-mandibular angle sensors, IMASEN), it was possible to determine the proportions of the undulations in the dive profile that resulted (or not) in prey capture. This methodology allowed the number of prey consumed to be estimated with a mean error of 10±6% using TDR data alone. If the mean mass of prey is known, then the overall mass of prey consumed per unit time can be determined. Additionally, the method allows estimation of the depth at which prey is taken and thus indicates how penguins exploit the water column. Due to its simplicity, the proposed methodology has applications for other Spheniscus penguin species and should be considered for other marine endotherm divers that show undulations in the dive depth profile.Communicated by O. Kinne, Oldendorf/Luhe 相似文献
156.
Bone charcoal is being developed as a treatment for decontaminating polluted water. In particular, its potential to adsorb metal species from contaminated water supplies is being examined. In this study, bone charcoal was used in batch and column experiments designed to investigate the sorption of two cationic metals Cu and Zn. The data from batch experiments fitted the Langmuir isotherm and so theoretical maximum binding capacities could be obtained. These values were compared with experimental values derived from the column experiments. The mechanisms involved in the immobilisation were also investigated. 相似文献
157.
Jonathan Mark Wilson Alexandre Leitão Ana Filipa Gonçalves Catarina Ferreira Patrick Reis-Santos Ana-Violeta Fonseca Joana Moreira da Silva José Carlos Antunes Cristina Pereira-Wilson João Coimbra 《Marine Biology》2007,151(5):1633-1645
The Anguillid juvenile glass eel must deal with the osmoregulatory consequences of highly variable environmental salinities
on its recruitment migration from coastal to fresh waters. Changes in ionoregulatory parameters and branchial ion transport
protein [Na+/K+-ATPase, Na+:K+:2Cl− cotransporter (NKCC), cystic fibrosis transmembrane regulator (CFTR) anion channel, V-type proton ATPase] expression (activities,
protein and/or mRNA level expression and/or cellular localization) in response to acclimation to a broad range of ionic strengths
[distilled water (DW) to hypersaline water (HSW; 150%) sea water (SW 32‰)] was studied. The estuarine glass eels were very
euryhaline and successfully acclimated to acute changes in environmental ionic strength from 50% SW, with high mortality only
observed in HSW (51%) and sublethal osmoregulatory indicators (whole body water content and sodium levels) disturbed at the
extremes (DW and HSW). Central to a high salinity acclimation were elevated branchial Na+/K+-ATPase, NKCC and CFTR expression. At lower salinity, Na+/K+-ATPase expression was maintained and NKCC and CFTR expressions were reduced. Branchial chloride cells increased in size up
to SW but decreased in HSW. During hypotonic disturbance (DW), no compensatory elevation in V-ATPase or Na+/K+-ATPase expression was observed. 相似文献
158.
Edward O. Wilson 《Behavioral ecology and sociobiology》1976,1(1):63-81
1. | Colonies of Pheidole dentata employ a complex strategy of colony defense against invading fire ants. Their responses can be conveniently divided into the following three phases: (1) at low stimulation, the minor workers recruit nestmates over considerable distances, after which the recruited major workers (soldiers) take over the main role of destroying the intruders; (2) when the fire ants invade in larger numbers, fewer trails are laid, and the Pheidole fight closer to the nest along a shorter perimeter; (3) when the invasion becomes still more intense, the Pheidole abscond with their brood and scatter outward in all directions (Figs. 1, 4). |
2. | Recruitment is achieved by a trail pheromone emitted from the poison gland of the sting. Majors can distinguish trail-laying minors that have just contacted fire ants, apparently by transfer of the body odor, and they respond by following the trails with more looping, aggressive runs than is the case in recruitment to sugar water. Majors are superior in fighting to the minors and remain on the battleground longer. |
3. | The first phase of defense, involving alarm-recruitment, is evoked most strongly by fire ants and other members of the genus Solenopsis; the presence of a single fire ant worker is often sufficient to produce a massive, prolonged response (Figs. 2, 5, 6). In tests with Solenopsis geminata, it was found that the Pheidole react both to the odor of the body surface and to the venom, provided either of these chemical cues are combined with movement. Fire ants, especially S. geminata, are among the major natural enemies of the Pheidole, and it is of advantage for the Pheidole colonies to strike hard and decisively when the first fire ant scouts are detected. Other ants of a wide array of species tested were mostly neutral or required a large number of workers to induce the response. The alarm-recruitment response is not used when foragers are disturbed by human hands or inanimate objects. When such intrusion results in a direct mechanical disturbance of the nest, simulating the attack of a vertebrate, both minor and major workers swarm out and attack without intervening recruitment. |
159.
Critical swimming speeds of late-stage coral reef fish larvae: variation within species,among species and between locations 总被引:3,自引:0,他引:3
Rebecca?FisherEmail author Jeffrey?M.?Leis Domine?L.?Clark Shaun?K.?Wilson 《Marine Biology》2005,147(5):1201-1212
The swimming abilities of larval fishes are important for their survival, potentially affecting their ability to avoid predators,
obtain food and control dispersal patterns. Near settlement swimming abilities may also influence spatial and temporal patterns
of recruitment. We examined Critical speed (U-crit) swimming ability in late stage larvae of 89 species of coral reef fishes from the Great Barrier Reef and the Caribbean.
Coefficients of variation in U-crit calculated at the individual level were high (28.4%), and this was not explained by differences in size or condition
factor of these same larvae. Among species U-crit ranged from 5.5 cm s−1 to 100.8 cm s−1 (mean=37.3 cm s−1), with 95% of species able to swim faster than the average current speed around Lizard Island, suggesting that most species
should be capable of influencing their spatial and temporal patterns of settlement. Inter-specific differences in swimming
ability (at both the family and species levels) were significantly correlated with size and larval morphology. Correlations
were found between swimming performance and propulsive area, fineness ratio and aspect ratio, and these morphological parameters
may prove useful for predicting swimming ability in other taxa. Overall, the swimming speeds of larvae from the same families
at the two locations were relatively similar, although the Lutjanidae and Acanthuridae from the Caribbean were significantly
slower than those from the great barrier reef. Differences in swimming speed and body form among late stage larvae suggests
that they will respond differently to factors influencing survival and transport during their pelagic phase, as well as habitat
use following settlement. 相似文献
160.
Appraisal of visual assessments of habitat complexity and benthic composition on coral reefs 总被引:4,自引:0,他引:4
Visual assessments of topographic habitat structure and benthos on coral reefs were appraised using quantitative data collected
from 16 replicate surveys within each of 21 sites on Seychelles reefs. Results from visual assessments of reef benthos were
similar to those obtained using techniques frequently used to assess benthic complexity and composition. Visual estimates
of habitat topography were correlated with rugosity, reef height and holes of 10–70 cm diameter, whilst visual estimates of
benthic composition were very similar to those obtained from line intercept transects. Visual estimates of topography correlated
strongly with species richness of fish communities and explained 42% of the variation in these data. The relationship between
visual estimates of topography and species richness is strongest with fish 10–30 cm total length (TL), abundance of fish within
this size category also correlating positively with topographic visual assessments. Visual techniques are prone to observer
bias, however with regular training they can be used to quickly provide a reliable and effective means of assessing habitat
complexity and benthos on coral reefs. 相似文献