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1.
《海洋科学》2011,35(6)
Harmful algal blooms and eutrophication: "strategies" for nutrient uptake and growth outside the Redfield comfort zone P M GLIBERT,J M BURKHOLDER:作者对有害赤潮和水体富营养化之间的复杂关系进行了回顾,阐述了为何营养盐的输入并不总是遵循Redfield比值而变化的,而许多有害藻华种类具有能在偏离经典的Redfield比值范围的营养盐条件下快速生长和增加毒素产量的能力:作者还对不同藻类在营养盐失衡条件下吸收营养盐与快速生长的生理机制进行了综述。  相似文献   

2.
A particular porosity method named "slot method" is implemented in a depth-integrated shallow water flow model (DIVAST) to simulate wetting and drying processes. Discussed is the relationship between the shape factors of the "slot" and the preset depth used in "wetting-drying" algorithm. Two typical tests are conducted to examine the performance of the method with the effect of the shape factors of the "slot" being checked in detail in the first test. Numerical results demonstrate that: 1 ) no additional effort to improve the finite difference scheme is needed to implement "slot method" in DIVAST, and 2) "slot method" will simulate wetting and diying processes correctly if the shape factors of the "slot" being selected properly.  相似文献   

3.
The protection of the biological diversity and the maintenance of the regional ecological integrity for the Huanghe (Yellow River) Estuary and its adjacent areas are practically significant and valuable. However, frequent human activities and natural climate changes have caused vigorous disturbances on the ecosystem in these sea areas. An objective assessment on the benthic habitat quality (BHQ) of the Huanghe Estuary and its adjacent areas is conducted, using AZTI's Marine Biotic Index (AMBI) and multivariate AMBI (M-AMBI) based on the data of macrobenthos in May and August 2011. The results show that both the indices do not correlate significantly, and their assessment results are greatly different. All of the samples assessed using the AMBI were "high" or "good", because the ecological group I (EGI) and the ecological group II (EGII) were dominant macrobenthic ecological groups in the research area. Owing to a low species' richness and a high individual abundance in some samples, the BHQ levels using the M-AMBI were worse than those of the AMBI. Significant correlations are observed between the M-AMBI, water depth, bottom water salinity and dissolved inorganic nitrogen, thus the M-AMBI could sensitively respond to environmental changes and distinguish influences from uninfluenced stations, but the AMBI could not. The consistent results between the AMBI and the M-AMBI mainly appeared in the uninfluenced (undisturbed or slightly disturbed) sta- tions. Therefore, the M-AMBI is more effective than the AMBI in assessing the benthic habitat quality in the Huanghe Estuary and its adjacent areas. Using the M-AMBI to assess the BHQ of the Huanghe Estuary and its adjacent areas, the results show that 3% of the stations are undisturbed and the BHQs are "high", and 61% of the stations are slightly disturbed and those of the BHQ are "good", and the rest are meanly disturbed and those of the BHQ are "moderate".  相似文献   

4.
Foraminiferal oozes were sampled from the tropical West Pacific seamount and seabed of deep sea,by a remotely operated vehicle(ROV)in December 2014 and March 2016.Using standard morphological method,four Miliolinella species,including Miliolinella obesa,M.circularis,M.suborbicularis and M.subrotunda were described.Among the four species,M.obesa is a new species.It is a large member(about 500μm in length)of the genus.This species is characterized by having a very stout and transverse broadly circular outline,and its body width is greater than the body length.In addition,its chamber demarcations are obscure from the exterior appearance.Three chambers are unclearly visible on one side and two chambers are visible on the opposite.Finally,we provided very detailed taxonomic microphotographs and the ecological distribution information for each species.  相似文献   

5.
The main objective of this study was to investigate toxic effects of the dinoflagellate Alexandrium species,on cladocera Moina mongolica in the laboratory.Ten strains of Alexandrium species,including Alexandrium tamarense(AT-6,ATHK,ATCI02,ATCI03 and AT5-1),A.catenella(ACDH),A.affine(AC-1 and AS-1),A.lusitanicum and A.minutum were tested.The results showed that A.tamarense(ATHK,ATCI02 and AT5-1) and A.affine(AC-1 and AS-1),but not A.tamarense(AT-6 and ATCI02),A.catenella(ACDH),A.lusitanicum and A.minutum had significantly negative effects on the survival of M.mongolica;when exposed to these ten strains of Alexandrium species in densities of 3 000 cells/cm 3 for 7 d,respecyively.M.mongolica could feed on A.tamarense(AT-6,ATHK,ATCI02,ATCI03 and AT5-1),A.catenella,A.lusitanicum and A.minutum,but exhibited little or no grazing on A.affine(AC-1 and AS-1),based on the changes in gut pigment after exposure to alga for 1 and 12 h.A.affine AC-1,which had the strongest toxicity on the survival of M.mongolica,was chosen to further study the negative effects on M.mongolica.The results showed that the effect of A.affine AC-1 on the survival of M.mongolica was density-dependent,and its lethal effects on one-day,two-day and three-day old M.mongolica were exacerbated with increasing age;The whole algal culture,re-suspended algal cells,cell fragments and cell contents all had adverse impacts on the survival of M.mongolica.Moreover,both juvenile numbers and life-span time of M.mongolica were decreased significantly when they were cultured in A.affine AC-1 of 10 and 50 cells/cm 3 ,combined with 3 × 10 6 cells/cm 3 of Chlorella spp.,respectively.As a non-PSP producer,A.affine may produce other toxins,responsible for the strong negative effects on M.mongolica.  相似文献   

6.
Melosira is one of the most common diatom genera found in freshwater ecosystems. There are many freshwater species of Melosira, of which M. varians is the most common. In our investigation of periphytic diatoms in the Jinsha River, China, a new species, M. capsularum sp. nov, was characterized in combined morphological and molecular approaches. M. varians was also analyzed using molecular data. The new species is similar to M. varians, M. moniliformis, M. nummuloides, and M. lineata in morpholog...  相似文献   

7.
Besides ozone, oxygen and water vapour should be considered for their absorptive effects on "HY--1A" CZI data processing. First ,gaseous transmittances under various conditions are computed and analyzed for the band settings of this sensor. Second, transmittances under six standard atmospheres are approximated as functions of zenith angle, the water vapour transmittance is approximated as a function of water vapour content and zenith angle, and the ozone transmittance is approximated as a function of ozone content and zenith angle. Finally, taking Rayleigh scattering as an example, the influence of ignoring gaseous absorption when calculating TOA reflectance is analyzed, and the effect of applying the presented transmittance approximations to gaseous absorption correction for Rayleigh scattering in "HY--1A" CZI data processing is evaluated.  相似文献   

8.
Pacific whiteleg shrimp(Litopenaeus vannamei) is an economically relevant shrimp species in many Asian countries. The specific objective of the current research was to assess microsatellite markers in screening the fastgrowth of domesticated L. vannamei stocks to establish a founder population for breeding-selection plans. The postlarvae produced by the reproduction of second generation broodstock were cultured in the same conditions throughout a five months growing period. Ninety juvenile shrimp were selected from the slow-, medium- and the fast-growth groups, and ten microsatellite markers were used to investigate their genetic diversity, and to understand the improvement of a breeding-selection scheme. Ten polymorphic loci(markers)(M1–M10) were produced at ten loci in this sample, among them Primer M8 was the highest polymorphic locus and M7 was the lowest one. A specific locus was found in the fast-growth group using Primer M5. The longest genetic distance(0.481) was determined between the fast- and medium-growth groups and the shortest(0.098) was between the slow- and medium-growth groups; therefore, the largest genetic identity(0.946) was observed between the slowand medium-growth groups and the smallest(0.667) was observed between the medium- and fast-growth groups.The Unweighted Paired Group with Arithmetic Average(UPGMA) dendrogram based on Nei's genetic distances provided two different groups; the first consist of the slow- and medium-growth groups and the second the fastgrowth group. Selection response and realized heritability for growth were 11.55% and 31.26%, respectively.Therefore, this set of microsatellite markers would provide a useful tool in shrimp breeding schemes.  相似文献   

9.
A three-dimensional isopycnic-coordinate internal tidal model is employed to investigate the generation,propagation, vertical structure and energy conversion of M2 internal tides in the Luzon Strait(LS) with mooring observations. Simulated results, especially the tidal current amplitudes, agree well with observations,demonstrating the reasonability and accuracy of the model. Results indicate that M2 internal tides mainly propagate into three directions horizontally, i.e., eastward towards the western Pacific Ocean, westward towards the Dongsha Island and southwestward towards the South China Sea Basin. In the horizontal direction, tidal current amplitudes decrease as distance increases away from the LS; in the vertical direction, they show an obvious decreasing tendency with depth. Between the double ridges of the LS, a clockwise gyre of M2 baroclinic energy flux appears, which is caused by reflections of M2 internal tides at supercritical topographies, and resonance of M2 internal tides happens along 19.5° and 21.5°N due to the heights and separation distance of the double ridges. The total energy conversion in the LS is about 14.20 GW.  相似文献   

10.
This paper presents the survey and research work of two land-sea profiles in the Bohai Sea, China, carried out in 2010-2011, including the seismic sources on land and in the sea, the ocean bottom seismographs (OBS) and their recovery, the coupling of OBS and the environment noise in sea area, the data quality of OBSs, and the result of data analysis. We focused on the investigation of crustal structures revealed by the two NE/EW-trending joint land-sea profiles. In combination with the Pn-velocity distribution and gravity- magnetic inversion results in the North China Craton, we propose that the undulation of the Moho interface in the Bohai and surrounding areas is not strong, and the lithospheric thinning is mainly caused by the thinning of its mantle part. The research result indicates that obvious lateral variations of Moho depth and seismic velocity appear nearby all the large-scale faults in Bohai Sea, and there is evidence of underplating and reforming of the lower crust by mantle material in the Bohai area. However, geophysical evidence does not appear to support the "mantle plume" or "delamination" model for the North China Craton destruction. The crustal structure of the Bohai Sea revealed "a relatively normal crust and obviously thinned mantle lid", local velocity anomalies and instability phenomena in the crust. These features may represent a combined effect of North China-Yangtze collision at an early stage and the remote action of Pacific plate subduction at a late stage.  相似文献   

11.
A feeding experiment was conducted to evaluate the ef fects of bulk zinc(B-Zn) and zinc nanoparticles(Zn-NPs) on survival, growth, compositions of amino acid and fatty acid, and nonspeci?c immune responses of the freshwater prawn, Macrobrachium rosenbergii post larvae. The B-Zn(size 10 μm)and Zn-NPs(size 50 nm) were supplemented separately with the basal feeds of M. rosenbergii at 60 mg/kg and feed without supplementation of any Zn source was served as a control. M. rosenbergii were fed these feeds for 90 days and the results showed that signi?cant( P <0.05) improvements in survival, growth, feed intake,speci?c growth rate, essential amino acids, unsaturated fatty acids, nonspeci?c immune responses(total haemocytes and dif ferential haemocytes count) of M. rosenbergii fed with B-Zn and Zn-NPs supplemented feeds when compared to control. Among these Zn sources, Zn-NPs supplemented feeds fed prawns showed signi?cantly( P <0.05) better performance than that of B-Zn and control. Hence, present study suggests that the 60 mg/kg Zn-NPs can be supplemented with basal feeds of M. rosenbergii for regulating better survival and growth.  相似文献   

12.
Rain effect and lack of in situ validation data are two main causes of tropical cyclone wind retrieval errors. The National Oceanic and Atmospheric Administration's Climate Prediction Center Morphing technique (CMORPH) rain rate is introduced to a match-up dataset and then put into a rain correction model to remove rain effects on "Jason-1" normalized radar cross section (NRCS); Hurricane Research Division (HRD) wind sPeed, which integrates all available surface weather observations, is used to substitute in situ data for establishing this relationship with "Jason-l" NRCS. Then, an improved "Jason-l" wind retrieval algorithm under tropical cyclone conditions is proposed. Seven tropical cyclones from 2003 to 2010 are studied to validate the new algorithm. The experimental results indicate that the standard deviation of this algorithm at C-band and Ku-band is 1.99 and 2.75 m/s respectively, which is better than the existing algorithms. In addition, the C-band algorithm is more suitable for sea surface wind retrieval than Ku-band under tropical cyclone conditions.  相似文献   

13.
1 Introduction M any estuarine and coastal copepods that havepreviously been classified as holoplankton m ightbestbe described as adultm eroplankton since they actuallyspend a portion oftheir life cycle in the seabed as rest-ing eggs [review ed by G rice and M arcus (1981) andM arcus (1996)]. R esting eggs can be extrem ely abun-dant (106 m ) in bays and estuaries especially w here -2w aterdepths are less than 20 m (M arcus,1989).Theyare likely to profoundly influence the dynam ics ofpel…  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.
A three-dimensional (3-D) finite volume coastal ocean model (FVCOM) was used for the study of water cir culation and seawater exchange in the Benoa Bay, Bali Island. The M2 tidal component was forced in open boundary and discharge from six rivers was included in the numerical calculation. The M2 tidal elevation produced by the FVCOM has a good agreement with the observation data. The M2 tidal current is also suc cessfully calculated under the ebb tide and flood tide conditions. The non-linear M2 tidal residual current was produced by the coastline geometry, especially surrounding the narrow strait between the Serangan Is- land and the Benoa Peninsula. The tidal residual current also generated two small eddies within the bay and one small eddy in the bay mouth. The salinity distribution influenced by river discharge could be success- fully calculated, where the numerical calculation and the observation results have a good correlation (r2) of 0.75. Finally in order to examine the seawater exchange in the Benoa Bay, the Lagrangian particle tracking method and calculation of residence time are applied. The mechanism of particle transport to the flushing of seawater is depicted clearly by both methods.  相似文献   

16.
1 IntroductionOstracodaisoneofthelargestgroupsoftheCrus-tacea (M artin and Davis, 2001), and the num bersofliving speciesofostracodesconsistof7 500. OneofthefrustratingaspectsforOstracodastudyisunstabili-tyofthehigherclassification status (Schram, 1986),w…  相似文献   

17.
Monotonic lateral load model tests were carried out on steel skirted suction caissons embedded in the saturated medium sand to study the bearing capacity. A three-dimensional continuum finite element model was developed with Z_SOIL software. The numerical model was calibrated against experimental results. Soil deformation and earth pressures on skirted caissons were investigated by using the finite element model to extend the model tests. It shows that the "skirted" structure can significantly increase the lateral capacity and limit the deflection, especially suitable for offshore wind turbines, compared with regular suction caissons without the "skirted" at the same load level. In addition, appropriate determination of rotation centers plays a crucial role in calculating the lateral capacity by using the analytical method. It was also found that the rotation center is related to dimensions of skirted suction caissons and loading process, i.e. the rotation center moves upwards with the increase of the "skirted" width and length; moreover, the rotation center moves downwards with the increase of loading and keeps constant when all the sand along the caisson's wall yields. It is so complex that we cannot simply determine its position like the regular suction caisson commonly with a specified position to the length ratio of the caisson.  相似文献   

18.
Harmful algal blooms and eutrophication:strategiesfor nutrient uptake and growth outside the Redfield comfort zoneP M GLIBERT,J M BURKHOLDER:作者对有害赤潮和水体富营养化之间的复杂关系进行了回顾,阐述了为何营养盐的输入并不总是遵循Redfield比值而变化的,而许多有害藻华种类具有能在偏离经典的Redfield比值范围的营养盐  相似文献   

19.
Tungsten and molybdenum in seawater can be sensitively and accurately determined by the polaro-graphic catalytic wave. In a supporting electrolyte containing HCl-benzilic acid-Nad, tungsten has a clear and stable catalytic wave. Then, the peak current of molybdenum increases as KClO3 is added into the above medium. The sensitivity of the proposed method is 5×10-2 M for W and 6×10-10 M for Mo, respectively.This method is an extremely quick, sensitive one and is suitable for the analysis of various kinds of water.  相似文献   

20.
To study the Taiwan Strait (TS), an unusual sea area, the numerical model in marginal seas of China is used to simulate and analyze the tidal wave motion in the strait. The numerical modeling experiments reproduce the amphidromic system of the M2 tide in the south end of the Taiwan strait, and consequently confirm the existence of the degenerate amphidromic system. On this basis, further discussion is conducted on the M2 system and its formation mechanism. It can be concluded that the tidal waves of the TS is consisted of the progressing wave from the north entrance and the degenerate amphidromic system from the south entrance, in which the progressing wave from the north entrance dominates the tidal wave motion in the strait. Except for the convergent effect caused by the landform and boundary, the degenerate amphidromic system produced in the south of the strait is another important factor for the following phenomena: the large tidal range in the middle of the strait, the concentrative zone of co-amplitude and co-phase line in the south of the strait. The degenerate amphidromic system is mainly produced by the incident Pacific Ocean tidal wave from the Luzon strait and the action by the shoreline and landform. The position of the amphidromic point is compelled to move toward southwest until degenerating by the powerful progressing wave from the north entrance.  相似文献   

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