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971.
Pinot noir, bastardo, rkaziteli and semillon grapes on vines grown in the Barossa Valley of South Australia were treated with a commercial dithianon formulation. The grapes were harvested by hand eight days later, and made into wine. Grab samples of berries, grape juice and the young wine were analysed for fungicide residues. No dithianon was detected in control grape samples, grape juices or wines. Significant dithianon levels were detected on the skins of treated grape samples. Dithianon is stable on the surface of grapes under the ambient conditions prevalent under the grape canopy for at least two weeks. No dithianon was detected in grape juice, on grape skins after berry crushing, in the lees, or in the young wine. Dithianon is unstable in grape juice and wine. Dithianon half‐life (initial concentration = 1 μg/mL) in semillon grape juice = 2.8 h, semillon wine = 0.58 h, pinot noir grape juice = 4.6 h, and pinot‐noir wine = 0.29 h. Treatment with fining agents or heat does not significantly reduce the rate of degradation. These results suggest that spraying table grapes with dithianon two weeks before harvest would result in exposure to essentially the full dose of active ingredient sprayed, and increase the risk to human health through ingestion of this compound. However, any threat to human health from ingestion through grape juice or wine is limited since any contact with grape juice or wine leads to rapid decomposition of dithianon by some as yet undetermined process. 相似文献
972.
Trevor J. Willis Christopher J. Sweeting Sarah J. Bury Sean J. Handley Julie C. S. Brown Debbie J. Freeman Dan G. Cairney Michael J. Page 《Marine Biology》2013,160(7):1633-1644
Using non-lethal tissue sampling for stable isotope analysis has become standard in many fields, but not for fishes, despite being desirable when species are rare or protected, when repeated sampling of individuals is required or where removal may bias other analyses. Here, we examine the utility of fish dorsal fin membrane as an alternative to muscle for analyzing δ13C and δ15N ratios in two reef fish species (blue cod Parapercis colias and spotty Notolabrus celidotus) that have differing feeding modes. Both species exhibited evidence of size-based feeding from fin δ15N values, but not from muscle. Blue cod fin δ15N increased steadily throughout the sampled size range (213–412 mm fork length), whereas spotty exhibited a distinct ontogenetic diet shift at approximately 120–140 mm fork length after which size-based feeding did not occur. Fin membrane was higher than muscle in δ13C in both species and in δ15N for blue cod, but fin δ15N was lower than muscle in spotty. The δ13C and δ15N fin–muscle offsets were constant in spotty regardless of size, while in blue cod, δ13C was constant with fish size, but δ15N offsets increased with increasing fish size. Non-lethal sampling utilizing fin tissue can be employed to estimate stable isotope values of muscle in fishes, but it is necessary to assess relationships among tissues and the effects of fish size on isotope values a priori for each species studied. Our data indicated that fin membrane may be a more sensitive tissue than muscle for detecting size-based feeding in some fish species using stable isotopes. A critical literature review revealed inconsistencies in tissue types tested, little understanding of tissue-specific trophic shift or turnover rates, and pseudo-replicated analyses leading to erroneous postulating of 1:1 relationships between tissues. 相似文献
973.
Inbreeding depression is a well-documented phenomenon. In animals, one means of avoiding the costs of inbreeding is through
the recognition and avoidance of kin as mates. Prairie voles (Microtus ochrogaster) are short-lived, socially monogamous rodents that demonstrate inbreeding depression in the laboratory. Field data indicate
that pair formation in nature is opportunistic but pairing among close relatives seems uncommon. We examined the role of relatedness
and familiarity on prairie vole social associations and reproduction by placing adult voles into 0.1-ha enclosures with familiar
siblings, unfamiliar siblings, and unrelated, unfamiliar conspecifics. Live-trapping data indicated that indices of social
pair bonding were random with respect to relatedness and familiarity. Among females whose litters were sired by a single male,
litters were significantly more likely to be sired by unfamiliar than familiar males, but the number of litters sired by males
that were unrelated to their partner was not different from the number of litters sired by males that were related to their
partner. Additionally, females that produced offspring with familiar siblings were significantly more likely to have litters
with multiple paternity than females not producing offspring with familiar siblings. However, multiple paternity was not influenced
by relatedness of sires. Finally, older individuals were more likely to produce offspring with each other than with younger
individuals. Our findings suggest that prior association is a more important mechanism of inbreeding avoidance than phenotype
matching for prairie voles mating under ecologically relevant conditions. 相似文献
974.
Nadon MO Baum JK Williams ID McPherson JM Zgliczynski BJ Richards BL Schroeder RE Brainard RE 《Conservation biology》2012,26(3):493-503
Sharks and other large predators are scarce on most coral reefs, but studies of their historical ecology provide qualitative evidence that predators were once numerous in these ecosystems. Quantifying density of sharks in the absence of humans (baseline) is, however, hindered by a paucity of pertinent time-series data. Recently researchers have used underwater visual surveys, primarily of limited spatial extent or nonstandard design, to infer negative associations between reef shark abundance and human populations. We analyzed data from 1607 towed-diver surveys (>1 ha transects surveyed by observers towed behind a boat) conducted at 46 reefs in the central-western Pacific Ocean, reefs that included some of the world's most pristine coral reefs. Estimates of shark density from towed-diver surveys were substantially lower (<10%) than published estimates from surveys along small transects (<0.02 ha), which is not consistent with inverted biomass pyramids (predator biomass greater than prey biomass) reported by other researchers for pristine reefs. We examined the relation between the density of reef sharks observed in towed-diver surveys and human population in models that accounted for the influence of oceanic primary productivity, sea surface temperature, reef area, and reef physical complexity. We used these models to estimate the density of sharks in the absence of humans. Densities of gray reef sharks (Carcharhinus amblyrhynchos), whitetip reef sharks (Triaenodon obesus), and the group "all reef sharks" increased substantially as human population decreased and as primary productivity and minimum sea surface temperature (or reef area, which was highly correlated with temperature) increased. Simulated baseline densities of reef sharks under the absence of humans were 1.1-2.4/ha for the main Hawaiian Islands, 1.2-2.4/ha for inhabited islands of American Samoa, and 0.9-2.1/ha for inhabited islands in the Mariana Archipelago, which suggests that density of reef sharks has declined to 3-10% of baseline levels in these areas. 相似文献
975.
Current taxonomy indicates a single global species of the Great Barracuda (Sphyraena barracuda) despite differences in color and behavior between Atlantic and Pacific forms. To investigate these differences and qualify
the dispersal characteristics of this unique coastal–pelagic teleost (bony fish), we conducted a global phylogeographic survey
of 246 specimens from thirteen sampling locations using a 629-base pair fragment of mtDNA cytochrome b. Data indicate high overall gene flow in the Indo-Pacific over large distances (>16,500 km) bridging several biogeographic
barriers. The West Atlantic population contains an mtDNA lineage that is divergent from the Indo-Pacific (d = 1.9%), while the East Atlantic (N = 23) has two mutations (d = 0.6%) apart from the Indo-Pacific. While we cannot rule out distinct evolutionary partitions among ocean basins based on
behavior, coloration, and near-monophyly between Atlantic and Indo-Pacific subpopulations, more investigation is required
before taxonomic status is revised. Overall, the pattern of high global dispersal and connectivity in S. barracuda more closely resembles those reported for large oceanic predators than reef-associated teleosts. 相似文献
976.
Predicting spread is a central goal of invasion ecology. Within marine systems, researchers have increasingly made use of
oceanographic circulation models to estimate currents and track species dispersal. However, the accuracy of these models for
predicting biological patterns, particularly for non-native species, has generally not been validated. Particularly, we wished
to examine the ability of models to predict physical and biological processes, which jointly determine the spread of marine
larval organisms. We conducted two empirical studies—a recruitment study and a drift card study—along the coast of New England,
USA, focusing on two invaders of concern—the European green crab (Carcinus maenas) and the Asian shore crab (Hemigrapsus sanguineus), to explicitly evaluate the ability of oceanographic models to predict patterns of spread. We used data from the large-scale
drift card study to validate our ability to capture dispersal patterns driven purely by physical processes. Next, we conducted
a recruitment study to evaluate our ability to reproduce patterns of biological dispersal. We were generally capable of reproducing
drift cards patterns—suggesting that the physical mechanics in the model were predictive. However, predicted biological patterns
were inconsistent—we were able to predict dispersal patterns for H. sanguineus but not for C. maenas. Our results highlight the importance of validating models and suggest that more work is necessary before we can reliably
use oceanographic models to predict biological spread of intertidal organisms. 相似文献
977.
Despite the important roles played by parasites in local population dynamics and community structure of marine ecosystems,
there is a lack of information on the geographical variation in infection levels displayed by particular host–parasite species
combinations. This study examines geographical variation in infection levels by the metacercarial stages of trematode parasites
in crustacean and bivalve second intermediate hosts. Analyses were based on a dataset compiled from the literature, consisting
of 164 local samples representing 49 host–parasite species pairs for crustaceans, and 338 entries representing 36 host–parasite
species pairs for bivalves. The analyses indicate that for all measures of infection levels [prevalence (percentage of individuals
infected), intensity (mean no. of metacercariae per infected individual), abundance (mean no. of metacercariae across all
individuals in a sample)], there was statistically significant repeatability of infection values within host–parasite species
pairs. However, it is only for values of intensity and abundance of infection in crustacean hosts that the repeatability was
strong; this suggests that infection levels are specific properties of crustacean–trematode species pairs, showing significant
consistency across localities despite spatial variation in abiotic and biotic conditions. Although the magnitude of variation
in infection levels within parasite species pairs (measured as coefficients of variation) was independent of scale in crustacean
hosts, infection levels in bivalves increased in variability at large (>100 km) spatial scales. These results suggest that
there is a considerable geographical consistency in parasite load, especially in crustacean hosts, which should lead to consistent
ecological and ecosystem effects of marine trematodes.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
978.
For small tube-building amphipods that live on the algae they consume, food and habitat are tightly linked. This study compared
two closely related amphipods to determine whether the species’ algal preferences are based on the food value of the algae
or on some other aspect of their algal habitat. Ampithoe lacertosa and Peramphithoe humeralis are both abundant on Shannon Point beach (Anacortes, Washington, USA; 48°30.542′ N, 122°41.070′ W) but specialize on different
algae. In observations and laboratory experiments conducted July–September 1997, 2007, and 2008, the two species exhibited
markedly different choices of food and habitat when offered six common macroalgae. Ampithoe
lacertosa ate all algae offered, but preferentially built tubes on the green alga Ulva
lactuca. Survival was relatively low among juveniles maintained on single species diets, except when they were fed Mazzaella splendens. Conversely, P.
humeralis consumed primarily the brown kelp Saccharina latissima, Alaria
marginata, and Desmarestia
ligulata and preferred those species for tube building. Juvenile P.
humeralis could not survive on a diet of U.
lactuca or M. splendens. While A.
lacertosa builds simple, temporary tubes and relocates frequently, P.
humeralis is a highly thigmotactic species that builds long-term, complex tubes on the alga it prefers to eat. Feeding and habitat
preferences of the two species were not clearly linked to nitrogen content of the algae, C:N ratio, or toughness of the algal
tissue. Instead, preferences of the species may be related to their mobility and the permanence of the tubes they build. Ampithoe
lacertosa and P.
humeralis also use different feeding strategies; the former appears to mix algae to produce a high-quality diet, while the latter is
more selective and has a capacity for compensatory feeding. The species are abundant on the same protected rocky shores, but
specialize on different algae for habitat and food. Results suggest that the nutritional requirements of these sympatric mesograzers
differ considerably and even closely related species can exhibit divergent behavioral strategies. 相似文献
979.
Lee WY Lannucci-Berger W Eitzer BD White JC Mattina MI 《Journal of environmental quality》2003,32(1):224-231
The half-lives of some persistent organic pollutants (POPs) in environmental compartments such as soil and air can be as long as decades. In spite of the hydrophobicity of many POPs, the literature contains reports of their uptake by, and translocation through, a variety of plants. Both these observations prompt the investigation of whether a vegetation-based environmental compartment such as compost contains significant residues of POPs. Previous reports imply that residues of technical chlordane will be found in compost. Due to its physicochemical properties, technical chlordane provides insights into the fate of POPs in the environment, which are not accessible through determinations of other pollutants in this group. Accordingly, we undertook the first comprehensive examination of technical chlordane residues in a variety of composts, specifically, 13 commercial and 39 municipal compost products, to both characterize and quantify the magnitude of this point source of contamination. Using chiral gas chromatography interfaced to ion trap mass spectrometry, the concentration and the compositional and enantiomeric profiles of chlordane components were determined. Of the 13 commercial products, 9 contained detectable chlordane concentrations, ranging from 4.7 to 292 microg/kg (dry wt.), while all 39 municipal products contained chlordane residues ranging from 13.9 to 415 microg/kg (dry wt.). The residue concentrations and profiles suggest possible feedstock sources for the chlordane in the finished compost product. The data also support the conclusion that some composts contribute to anthropogenic cycling of POPs through the biosphere. 相似文献
980.
In this study, synthesis and speciation of polyaluminum chloride (PAC) for application in water treatment was investigated using a colorimetric speciation method. It was possible to produce stable preparations of PAC solutions in which a relatively stable cationic polymer predominated. The mode of preparation has a dramatic effect on the composition of PAC preparation. Some important parameters such as hydroxyl ligand number, mixing intensity, base injection rate and method, and aging were identified in this study. 相似文献