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931.
B. Miller # R. Reading J. Hoogland † T. Clark ‡ G. Ceballos § R. List S. Forrest †† L. Hanebury ‡‡ P. Manzano § J. Pacheco § and D. Uresk§§ 《Conservation biology》2000,14(1):318-321
932.
Thomas Eisner Maria Eisner Daniel J. Aneshansley Chia-Li Wu Jerrold Meinwald 《Chemoecology》2000,10(4):211-216
Summary. The mint plant, Teucrium marum (family Labiatae), sometimes called cat thyme, contains two methylcyclopentanoid monoterpenes, dolichodial and teucrein. The former compound is potently anti-insectan. It is repellent to ants (Monomorium pharaonis) and induces preening reflexes in flies (Phormia regina) and cockroaches (Periplaneta americana). Evidence is presented suggesting that dolichodial, which is presumed to be the plant's chief defensive agent, is stored in the tiny epidermal capsules that beset the leaves. It is only when the leaves are injured (and the capsules ruptured) that the leaves become repellent. Teucrein, in contrast, has no anti-insectan potency. It is present predominantly in the leaf buds, unlike dolichodial, which is present mostly in mature leaves. It is argued that teucrein is the storage compound from which dolichodial is generated during leaf development. 相似文献
933.
934.
After introducing soft defence techniques as an alternative to hard defence techniques, the need is emphasized to consider
the coastal area as an integral system. By recalling the main driving factors for coastal management: conflict resolution,
resilience and sustainability, we logically arrive at the concepts of ecological engineering and ecotechnology, which are
increasingly acknowledged as possible solutions to achieve sustainable use of coastal space as a resource. In this context,
we refer to the principles of self design and of ecosystem conservation.
In order to deal with real situations we are in need of fundamental ‘tools’ for the application of the soft intervention technology
approach. We therefore introduce the concept of physiographic units and develop an initial elaboration for a coastal stretch
and for coastal wetlands. The latter deserve more attention because of the already established practices of ecotechnology,
at least as far as water and soil quality are concerned, but certainly also concerning morphology, especially in the future.
We conclude by briefly discussing how activities undertaken in two research projects currently being conducted under the framework
of the Marine Science and Technology Program of the Commission of the European Communities are expected to contribute to the
concepts introduced here. 相似文献
935.
Jürgen Warrelmann Hartmut Kochler Tobias Frische Ingo Dobner Ulrich Walter Wolfgang Heyser 《Environmental Sciences Europe》2000,12(6):351-357
On the area of a former ordnance plant (‘Werk Tanne’, Clausthal-Zellerfeld, Germany), a field experiment for phytoremediation of TNT-contaminated soils has been carried out since May 1999. The concept is based on a stepwise degradation of TNT by white-rot fungi and mycorrhiza within the rhizosphere of site-specific seedlings. An appropiate site with contaminants in the surface-soil was prepared with a large-scale soil grader and subsequently divided into different experimental plots, including an uncontaminated control as well as a contaminated plot without treatment. Planting of the selected trees and shrubs (infected with mycorrhiza during nursery) and inoculation with wood chips (inoculated with white-rot fungi) is followed by a detailed monitoring of the experimental plots (chemical analyses, biotest-battery, ecological field indicators). For the evaluation of the results, multivariate methods are applied. 相似文献
936.
The fermentation activity of the yeastSaccharomyces cerevisiae is used as a bioindicator to detect aquatoxic effects. This is done by measuring the CO2 production of yeast cells after a multiplication period affected by toxic substances. The concentration of toxicants diminishing the fermentation by 20% is taken as a characteristic value (EC20). Organic compounds (unpolar and polar narcotics), inorganic salts (especially of heavy metals), surfactants and plant pesticides were tested. The results are compared so far as available with data of a ciliata assay usingTetrahymena pyriformis. A congruence of 90% and an equal sensibility of the assays resulted. The results of the yeast assay are therefore representative for ecotoxicological testing. The yeast assay is reproducible, easy to handle, and offers an alternative for sewage testing because sterile handling is not necessary. 相似文献
937.
L. Zane L. Ostellari L. Maccatrozzo L. Bargelloni J. Cuzin-Roudy F. Buchholz T. Patarnello 《Marine Biology》2000,136(2):191-199
Meganyctiphanes norvegica (M. Sars)is a pelagic crustacean that plays a key role in marine food webs of North Atlantic Ocean and marginal seas. We
studied eight population samples collected in the European Atlantic and Mediterranean Sea. By means of single strand conformation
polymorphism analysis (SSCP) and direct sequencing, we investigated a segment of 158 base pairs of the mitochondrial gene
coding for the subunit 1 of NADH dehydrogenase. We found 12 sequence variants among the 385 individuals studied. Analysis
of molecular variance (AMOVA) showed that 14.75% of the total genetic variability was explained by differences between populations,
thus indicating absence of panmixia for these populations. Pairwise comparisons revealed three distinct genetic pools: the
first one represented by Cadiz Bay, the second one by the Ligurian Sea, and the third one included all the NE Atlantic samples.
We also investigated one population from the Alboran Sea (within the Mediterranean basin, east of the Strait of Gibraltar).
This population was found to be genetically intermediate between the NE Atlantic samples and the Ligurian sample, suggesting
that the restriction to the gene flow is not associated with the Strait of Gibraltar, but possibly with the Oran–Almeria oceanographic
front. The present work indicates that M. norvegica, although endowed with a high dispersal capacity because of its pelagic habit, can develop separate breeding units inside
the same oceanic basin (the Atlantic). Furthermore, the Ligurian sample should be considered as a distinct evolutionary entity,
separated from the Atlantic population.
Received: 2 May 1999 / Accepted: 26 November 1999 相似文献
938.
We investigated the effect of different densities of the burrowing deposit-feeding amphipod Monoporeia affinis on the potential for recruitment of zooplankton from benthic resting eggs. Hatching of resting eggs was induced in the laboratory
on sliced and resuspended 1-cm depth-sections of sediment cores, collected at six stations in an archipelago area of the Gulf
of Bothnia, Baltic Sea. The uppermost 5 cm of the sediment was studied. The most common species that hatched was Eurytemora affinis (Copepoda). Individuals from another copepod genus, Acartia, hatched in significant numbers only in the cores from two stations with low amphipod abundance. Cores from stations with
high amphipod densities showed a deeper distribution of emerging E. affinis nauplii compared with stations with few amphipods; the oxidised sediment layer was also deeper at high M. affinis densities than at low. Total (0 to 5 cm strata pooled) number of hatched E. affinis nauplii was independent of amphipod density. This indicates that the effect of M. affinis on E. affinis eggs involves deeper burial due to bioturbation, rather than predation. Decreased benthic recruitment of zooplankton at localities
with high M. affinis density is suggested, since more deeply positioned eggs are less likely to hatch. When hatching was induced in intact, non-sliced
cores from one station, the number of E. affinis nauplii that hatched was on average 43% of the number that hatched in the upper centimetre of the sliced cores from the same
station. This fraction (43%), if applied to the other stations, implied a potential for benthic recruitment of up to 80 000 ind
m−2 for E. affinis. Due to its high abundance, M. affinis is likely to greatly reduce benthic recruitment of zooplankton in this system.
Received: 17 September 1999 / Accepted: 23 February 2000 相似文献
939.
The Chilean intertidal Lottiidae limpet fauna consists of at least nine species, grouped into the monophyletic taxon Scurria and a single taxon preliminarily designated as `Lottia' orbignyi (Dall). Within the Scurria clade, the most basal species are Scurria variabilis (Sowerby), S. viridula (Lamarck), and S.zebrina (Lesson), and among the most crown groups are S. ceciliana (Orbigny) and S. araucana (Orbigny). This phylogenetic information, obtained by the analysis of molecular characters (16S mtDNA), provides a framework
for a comparative study of behavioral characters. In this study, we analyze the escape responses of two basal limpet species
(`L.' orbignyi and S. viridula) and two derived limpet species (S. araucana and S. ceciliana) in the presence of the limpet predatory seastar Heliaster helianthus (Lamarck) and the limpet non-predatory seastars Stichaster striatus Muller and Troschel and Patiria chilensis Lutken. Neither P.chilensis nor Stichaster striatus induced escape responses such as those observed with the predatory H. helianthus. Moreover, in the presence of H. helianthus, basal and derived limpet species differed significantly in the percentage of individuals responding, reaction time, and
duration of the response. The basal species `L.' orbignyi and Scurriaviridula exhibited instantaneous and vigorous locomotor responses, whereas the derived species S. araucana and S. ceciliana displayed no locomotor responses. The same pattern was found in responses to H. helianthus homogenates. The results strongly suggest a correlation between phylogeny and anti-predator escape responses to the seastar
H. helianthus. Alternative escape responses have evolved for basal and derived species within the Chilean clade.
Received: 27 April 2000 / Accepted: 16 August 2000 相似文献
940.
The isopod Munnopsurus atlanticus occupies bathyal depths in both the Bay of Biscay (NE Atlantic; between 383 and 1022 m) and in the Catalan Sea (Northwestern
Mediterranean; between 389 and 1859 m). The species was dominant in both assemblages, reaching bathymetric peaks of abundance
on the upper part of the continental slope (400 m depth) in the Bay of Biscay and at ˜600 m in the Catalan Sea. Both the Atlantic
and the Mediterranean populations are bivoltines. Demographic analysis of the Bay of Biscay population revealed the production
of two generations per year with different potential longevity (5 mo for G1 and 11 mo for G2). The mean cohort-production interval (CPI) was estimated at 8 mo, and results of the demographic analysis were also used
to estimate production for the Catalan Sea populations. Mean annual density (D) and biomass (B) were higher in the Bay of
Biscay (D = 356.7 individuals 100 m−2; B = 0.803 mg dry wt m−2 yr−1) than in the Mediterranean (D = 16.3 individuals 100 m−2; B = 0.078 mg dry wt m−2 yr−1). Also, mean annual production was an order of magnitude higher in the Atlantic (between 4.063 and 4.812 mg dry wt 100 m−2 yr−1 depending on the method used) than in the Catalan Sea (between 0.346 and 0.519 mg dry wt 100 m−2 yr−1). M. atlanticus feeds on a wide variety of benthic and pelagic food sources. In both study areas, phytodetritus was not important in the
diet of M. atlanticus. In contrast, gut-content data suggested an indirect coupling with phytoplankton production in both areas via foraminiferans.
The life history and the recorded production are considered in respect to both the dynamics and levels of primary production
and the total mass flux in the respective study areas. Differences in the secondary production of both populations seemed
to be more consistently explained by differences in total mass flux than by differences in the primary production levels;
this is also consistent with the variety of food sources exploited by M. atlanticus.
Received: 22 February 1999 / Accepted: 3 February 2000 相似文献