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941.
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
942.
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
943.
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
944.
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
945.
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
946.
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
947.
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
948.
Relatively few insects have invaded the marine environment, and only five species of sea skaters, Halobates Eschscholtz (Hemiptera: Gerridae), have successfully colonized the surface of the open ocean. All five species occur in the
Pacific Ocean, H. germanus White also occurs in the Indian Ocean, whereas H. micans Esch- scholtz is the only species found in the Atlantic Ocean. We sequenced a 780 bp long region of the mitochondrial cytochrome
oxidase subunit I gene (COI) for a total of 66 specimens of the five oceanic Halobates species. Our purpose was to investigate the genetic variation within species and estimate the amount of gene flow between
populations. We defined 27 haplotypes for H. micans and found that haplotype lineages from each of the major oceans occupied by this species are significantly different, having
sequences containing five to seven unique base substitutions. We conclude that gene flow between populations of H. micans inhabiting the Atlantic, Pacific, and Indian Ocean is limited and hypothesize that these populations have been separated
for 1 to 3 million years. Similarly, there may be limited gene flow between H. germanus populations found in the Pacific and Indian Ocean and between H. sericeus populations inhabiting the northern and southern parts of the Pacific Ocean. Finally, we discuss our findings in relation
to recent hypotheses about the influence of oceanic diffusion on the distribution and population structure of oceanic Halobates spp.
Received: 29 July 1999 / Accepted: 23 November 1999 相似文献
949.
The annual epidemic spawning period of a Scottish population of Arenicola marina (L.) has been recorded over a period of 13 yr. This population spawns between mid-October and mid-November in a discrete
spawning event over a period of 4 to 5 d. Endocrine manipulation experiments showed that spawning is induced in females only
if sufficient titres of PMH (prostomial maturation hormone) are present in the prostomia. These levels are attained during
the 2 to 3 wk prior to the natural spawning date. The East Sands, St. Andrews population always spawns during periods of spring
tides regardless of tidal amplitude or whether they are full- or new-moon tides. Meteorological data, including sea-temperature
data were collected for each year, and correlation of the environmental data with spawning time was attempted. Correlation
of spawning times with weather patterns showed that mean daily air pressures were significantly higher during the spawning
period than from September to November as a whole. Evidence also suggests that a reduction in sea temperature is required
prior to spawning. A significant moderate negative correlation was found between May to July air temperatures and spawning
date, suggesting that higher May to July temperatures may induce early spawning. Daily rainfall and wind speed were also lower
during the spawning period, but not significantly so. These results indicate that air pressure (or changes therein) may act
as a final spawning cue, and the advantages of this are discussed in relation to fertilization success. A model of the interplay
between environmental parameters and the endocrine mechanisms controlling the induction of spawning is proposed. Higher than
average summer temperatures may advance gametogenesis to bring the population into a state of maturity (full-size oocytes,
well-developed sperm morulae), and may also advance spawning time. Once the population has completed gametogenesis, a drop
in sea temperature is then required to trigger an increase in endocrine titres within the prostomium, without which spawning
cannot be induced by prostomial injection. The population spawns on spring tides; however a lack of clement weather coinciding
with the spring tide will result in population-wide spawning being aborted, as in 1996. Clement weather (high pressure, low
rainfall and wind speed) in conjunction with spring tides permits spawning to proceed to completion.
Received: 21 June 1999 / Accepted: 25 January 2000 相似文献
950.
Modulation of the free amino acid pool and protein content in populations of the brine shrimp Artemia spp. 总被引:3,自引:0,他引:3
S. Helland G. V. Triantaphyllidis H. J. Fyhn M. S. Evjen P. Lavens P. Sorgeloos 《Marine Biology》2000,137(5-6):1005-1016
Free amino acid (FAA) and protein content were measured in various developmental stages of Artemia franciscana, from cysts to Instar III metanauplii. In addition, decapsulated cysts of 15 Artemia populations from different localities were compared with respect to their FAA and protein content. Furthermore, the content
and composition of the FAA pool were modulated by hatching the cysts at various salinities, and by enriching the nauplii with
algae or a lipid-enrichment emulsion. The FAA content increased threefold from cysts to nauplii, and Instar III metanauplii
contained nearly 50% taurine of total FAA. Cysts of A. franciscana were found to contain one-third the amount of FAA compared to the other Artemia species investigated. The content and pool composition of FAA was successfully modulated in 11 of 13 populations, where by
the content of FAA was significantly increased when hatched at high salinity. Finally, enrichment elevated the content of
FAA and changed the pool composition, thereby showing a dietary effect. Algal enrichment also increased the protein content.
Received: 27 September 1999 / Accepted: 17 July 2000 相似文献