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1.
An automatic measuring system called “FerryBox” was installed in the North Sea on a ferry travelling between Germany (Cuxhaven) and Great Britain (Harwich), enabling online oceanographic and biological measurements such as salinity, temperature, fluorescence, turbidity, oxygen, pH, and nutrient concentrations. Observations made along the ferry transect reveal characteristic phenomena such as high salinity inflow through the Channel into the Southern Bight, algal bloom dynamics and related oxygen and pH changes. Combination of these online observations with remote sensing enhances the spatial resolution of the transect related measurements. Several examples of the synergy between these two measuring strategies are shown, both for large-scale algal blooms in the North Sea as well as for local intense but short-term blooms in the German Bight. Coherence of the data sets can be gained and improved by using water transport models in order to obtain synoptic overviews of the remotely sensed and FerryBox related parameters. Limitations of the currently used algorithms for deriving chlorophyll-a from remote sensing images for coastal and shelf seas (Case-2 water) are discussed, as well as depth related processes which cannot be properly resolved on the basis of water intake at a fixed point. However, in unstratified coastal waters under normal conditions FerryBox data represent average conditions. The importance of future applications of this combination of methods for monitoring of coastal waters is emphasized.  相似文献   

2.
In the Mediterranean region, herbivory appears to be a factor controlling the production of the endemic species Posidonia oceanica, which is mainly due to two main macroherbivores: the sea urchin Paracentrotus lividus, and the sparid fish Sarpa salpa. In this context the present study is a contribution in clarifying herbivory on P. oceanica by testing: 1) whether the abundance of grazing marks of the two herbivores is variable across different spatial scales, 2) whether spatial variation of P. lividus grazing marks and its density is consistent, 3) whether there is a dependence of the number of P. lividus grazing marks on its density, 4) whether the grazing of both macroherbivores, P. lividus and S. salpa, involves the entire leaf length, and 5) whether there is a dependence of the number of P. lividus grazing marks on the number of S. salpa grazing bites.  相似文献   

3.
The present study is the first to compare trophic relationships of several co-occurring phytal harpacticoid species, in their natural habitat, using both δ13C and δ15N signatures. Three phytal harpacticoid species/taxa (Zaus spinatus, Tisbe spp., and Parathalestris cf. intermedia) all collected from the alga Fucus serratus, at different times of the year, were analyzed. The results indicated that the harpacticoids were utilizing food sources differently. Specific food sources of the three species/taxa could not be accurately pinpointed, but there were strong indications that F. serratus and fragments from it did contribute significantly to the diet of P. cf. intermedia and Tisbe spp. Both of these harpacticoid species overlapped in δ13C and δ15N values with some of the macrofaunal species, collected from the same site in Hvassahraun, Iceland, while no overlap was seen for Z. spinatus. The signatures for Z. spinatus indicated that its food sources changed seasonally.  相似文献   

4.
5.
INTRODUCTIONAequorinisabioluminescentprotein ,isolatedfrom jellyfishAequorea .Theaequorincomplexconsistofa 2 2 0 0 0Mrapoaequorinprotein ,molecularoxygenandtheluminophorecoelenterazine .WhenthreeCaionsbindtothiscomplex ,coelenterazineisoxidizedtocoelen teramide…  相似文献   

6.
High Reynolds number flows around a circular cylinder close to a flat seabed have been computed using a two-dimensional standard high Reynolds number kε turbulence model. The effects of gap to diameter ratio, Reynolds number and flat seabed roughness for a given boundary layer thickness of the inlet flow upstream of the cylinder have been investigated. Hydrodynamic quantities and the resulting bedload transport have been predicted, and the vortex shedding mechanisms have been investigated. Predictions of hydrodynamic quantities around a cylinder located far away from the bed (so that the effect of the bed is negligible) are in satisfactory agreement with published experimental data and numerical results obtained for the flow around an isolated cylinder. Results for lower Reynolds number flows have also been computed for comparison with the high Reynolds number flow results. Overall it appears that the present approach is suitable for design purposes at high Reynolds numbers which are present near the seabed in the real ocean.  相似文献   

7.
A survey within the French National Programme of Ecotoxicology was carried out in 2002, 2003 and 2004 to study the response of Nereis diversicolor populations (Polychaeta, Nereididae) to the impact of pollution in the Authie estuary (non-contaminated site) and in the Seine estuary (contaminated site). In the period studied, the density varied from 672 ind. m−2 to 3584 ind. m−2 in the Authie estuary and from 80 ind. m−2 to 920 ind. m−2 in the Seine estuary. Biomass varied from 3.94 g m−2 (dry weight) in February 2004 to 38.0 g m−2 in August 2003 in the Authie estuary and from 3.4 g m−2 in February 2002 to 0.6 g m−2 in February 2004 in the Seine estuary. Density and biomass of the populations of N. diversicolor were consistently lower in the Seine estuary than in the Authie estuary. Size frequency histograms permit the analysis of the cohorts as well as the elaboration of the growth curves. For the individuals from the Authie estuary, the relation between dry weight (DW) and length L3 (prostomium, peristomium and chaetiger 1) was DW = 4.2205 L32.9832. For those from the Seine estuary, the relation between dry weight and L3 was DW = 0.4697e1.7209L3. The individuals of N. diversicolor should belong to eight cohorts in Authie estuary (two cohorts each year) instead of six cohorts for those from the Seine estuary. These differences can be attributed to the effect of pollution on the population of N. diversicolor.  相似文献   

8.
Effects of the mixture of β-ecdysone and polypodine -B (2 : 1 W/W) on the moulting and growth of prawn, Penaeus orientaliss were studied in laboratory by rearing the animal with the added compound diets. The results showed that the addition of the moulting hormone (M. H) mixture to compound diets, from 1. 33× 10-6 to 30×10-6, could increase moulting activity and growth rate of the prawn to different extents, among which the 5. 33× 10-6-10. 67×10-6addition had statistically significant effects. However, 60 × 10-6 added diets caused moulting and growth inhibitions and cuticle thickening. The analyses of protein, water and ash contents of the prawn showed no remarkable differences between hormone dosed animals and the control.  相似文献   

9.
Coastal and estuarine areas in the Bay of Biscay are essential nursery habitats for sole (Solea solea). Using three intronic markers, we investigated patterns of genetic differentiation among cohorts of juveniles (0+, 1+, sub-adults) inhabiting four major nurseries in the Vilaine and Loire river estuaries, the Pertuis d'Antioche strait, and the Gironde estuary. Genetic differentiation was not significant for the age 0- and 1-groups, but was among sub-adult samples (θWC = 0.017; P = 0.031). Hierarchical analyses of genotypic frequencies by nested multivariate ANOVA using redundancy analysis indicated that northern nurseries of Loire and Vilaine rivers had different patterns of genotypic variation with age than southern nurseries of the Pertuis d'Antioche and Gironde estuaries (F = 1.36; P = 0.007). Bay of Biscay nurseries appeared to be spatially structured between a southern and a northern group that exhibit different genotypic distributions. Genetic drift and gene flow explains this pattern poorly, but a statistical test (P < 0.035) suggested that the metallothionein (MT) locus may be significantly impacted by selection in southern estuaries. As metallothionein is involved in heavy-metal detoxification, and southern nurseries are known to be affected by cadmium, this indicates a possible correlation between observed genotypic distributions and some nursery habitat features in sole. Some selective patterns might also be proposed to explain patterns of linkage disequilibrium observed at amylase loci in three of the four nurseries.  相似文献   

10.
SubunitcompositionandchromophorecontentofR-phycocyaninandallophycocyaninfromPorphyrahaitanensis¥GaoHongfeng;CaoWendaandJiMing...  相似文献   

11.
The spatial variability of seagrass meadows in Arcachon Bay, was studied between 1988 and 2008 using a combination of mapping techniques based on aerial photographs for intertidal dwarf-grass (Zostera noltii) beds and acoustic sonar for permanently submerged eelgrass (Zostera marina) populations. The results show a severe decline over the period for both species, as well as an acceleration of the decline since 2005 for Z. noltii. The total surface regression over the studied period is estimated to be 22.8 km2 for Z. noltii and 2.7 km2 for Z. marina, which represent declines of 33 and 74% respectively.  相似文献   

12.
A higher-order non-hydrostatic σ model is developed to simulate non-linear refraction–diffraction of water waves. To capture non-linear (or steep) waves, a 4th-order spatial discretization is utilized to approximate the large horizontal pressure gradient. A higher-order top-layer pressure treatment is further implemented to resolve wave propagation. The model's characteristics including linear wave dispersion and non-linearity are carefully examined. The accuracy of the present model using only two vertical layers is validated by laboratory data and the available results predicted by the non-linear Schrödinger equation, Boussinesq-type equations, the non-linear mild slope equation, and the Laplace equation. Features of harmonic generation as well as the influences of dispersion and non-linearity on wave energy transfer processes are discussed.  相似文献   

13.
Effectsoflight,temperatureandnutrientsonphotosynthesisofBiddulphiaregiaINTRODUCTIONLight,temperatureandnutrientsareimportante...  相似文献   

14.
The impacts of Prorocentrum donghaiense Lu and Alexandrium catenella Balech, causative species of the large-scale HAB in the East China Sea, were studied under laboratory conditions. According to bloom densities, the effects of monoculture and mixture of the two species were examined on the egg-hatching success of Argopecten irradians Lamarck, and the population growth of Brachionus plicatilis Müller and Moina mongolica Daday. The results showed that monoculture of A. catenella had a significant inhibition on the egg hatching success of A. irradians, and the population growth of B. plicatilis and M. mongolica. The median effective densities (ED_50) inhibiting the egg hatching success of A. irradians for 24 h and the population growth of B. plicatilis and M. mongolica for 96 h were 800, 630, and 2 400 cells/cm3, respectively. Monoculture of P. donghaiense has no such inhibitory effect on the egg hatching success of A. irradians; P. donghaiense at lower suitable densities could sustain the population growth of B. plicatilis (1×104~3×104cells/cm3) and M. mongolica (2×104~5×104cells/cm3); P. donghaiense at higher densities had significantly adverse effect on the population growth of B. plicatilis (4×104~10×104cells/cm3) and M. mongolica (10×104cells/cm3). When the two algae were mixed according to bloom densities, P. donghaiense at suitable densities to some extent could decrease the toxicity of A. catenella to B. plicatilis and M. mongolica. The results indicated that the large-scale HAB in the East China Sea could have adverse effect on zooplankton, and might further influence the marine ecosystem, especially when there was also Alexandrium bloom.  相似文献   

15.
1 IntroductionBothEpinephelus malabaricusandE. coioidesbelong to the genusEpinephelus(Perciformes: Ser-ranidae: Epinephelinae).They are warm water reeffishes that have similar distribution ranges as well assimilar morphological characteristics, which have…  相似文献   

16.
Based on the morphocytological studies on Planktoreiella,two species of the genus, p. sol Schütt and p. formosa (Qian et Wang) are recorded in China''s seas. The renaming of the latter species is based on a careful study on Valdiuella formosa (Schimper ex Karsten) Karsten.  相似文献   

17.
1Introduction Afossorialmodeoflifehasbeenadoptedbynu merousfishes(Gibson,1982).Burrowingmodeof lifeclearlyoffersanumberofadvantages,butburro wingfishmustalsobeadaptedtocopewiththespe cialproblemsthatthislifestylepresents.Fishthat constructburrowsininterti…  相似文献   

18.
Abstract-Based on the research of juvenile (2, 3, 4 months) growth and survival of three popu-lations of two different geographic areas in Chlamys farreri from Russian and China and their F_1 hybridsderived from Chinese cultural population (CC)×Russian population (RW), Chinese wild popu-lation (CW)×Russian population (RW), Russian population (RW)×Chinese wild popula-tion (CW), the study of the medium-term (6, 8, 10, 12 months) growth and development ofChlamys farreri was carried out. The four determined results indicated that there existed different ex-tent heterosis (3%~52%) for the growth in three types of F_1 hybrids, and the offspring derived fromCC×R had a stronger heterosis among the crosses at the medium-term; the uptrend among traitsare wet weight>shell width>shell length>shell height, Chinese cultural population could be recog-nized as excellent parent, and seasonal variations influence very much on the daily increment and growthrate of each trait of Chlamys farreri and it is only able to  相似文献   

19.
Gravitational Potential Energy (GPE) change due to horizontal/isopycnal eddy diffusion and advection is examined. Horizontal/isopycnal eddy diffusion is conceptually separated into two steps: stirring and sub scale diffusion. GPE changes associated with these two steps are analyzed. In addition, GPE changes due to stirring and subscale diffusion associated with horizontal/isopycnal advection in the Eulerian coordinates are analyzed. These formulae are applied to the SODA data for the world oceans. Our analysis indicates that horizontal/isopycnal advection in Eulerian coordinates can introduce large artificial diffusion in the model. It is shown that GPE source/sink in isopycnal coordinates is closely linked to physical property distribution, such as temperature, salinity and velocity. In comparison with z-coordinates, GPE source/sink due to stir ring/cabbeling associated with isopycnal diffusion/advection is much smaller. Although isopycnal coordi nates may be a better choice in terms of handling lateral diffusion, advection terms in the traditional Eule rian coordinates can produce artificial source of GPE due to cabbeling associated with advection. Reducing such numerical errors remains a grand challenge.  相似文献   

20.
Breeding numbers of Laridae and other surface-nesting seabirds have been monitored at sub-Antarctic Marion Island since 1996/1997 and counts of breeding birds were made at nearby Prince Edward Island in December 2001 and December 2008. Four species are regular breeders at the islands: Subantarctic skua Catharacta antarctica, kelp gull Larus dominicanus, Antarctic tern Sterna vittata and Kerguelen tern S. virgata. The latter three species currently each have populations of below 150 breeding pairs at the islands. Kelp gull numbers appear to be relatively stable though they may have decreased since the 1980s. Kerguelen tern numbers decreased and then recovered at Marion Island, but numbers of the species have declined at Prince Edward Island and it maintains a tenuous foothold there. The small Antarctic tern population appears to be stable.  相似文献   

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