南海带鱼遗传变异及其分类的研究

带鱼是我国海洋鱼类中最重要的经济鱼类,过去进行了大量的研究,多认为中国近海的带鱼为一个种,而不同的学者分别认为存在3,4和5个种群。从1976年开始,我们试图主要用生化方法并结合形态学资料研究带鱼的分类。1983和1988年报道了我们通过带鱼肌浆蛋白和形态学部分资料的研究认为中国近海带     

Application of Monte-Carlo statistical experiments in design of ocean engineering——Estimating the parameters, models and probabilities

Recently, some results have been acquired with the Monte- Carlo statistical experiments in the design of ocean en gineering. The results show that Monte-Carlo statistical experiments can be widely used in estimating the parameters of wave statistical distributions, checking the probability model of the long- term wave extreme value distribution under a typhoon condition and calculating the failure probability of the ocean platforms.     

A study on the exchange additivity of zinc in solid mixtures in seawater——Ⅱ.Stepwise exchange in δ-MnO2/montmorrillonite mixture

In this study the zinc exchange process and the reason for the non-additive exchange of δ-MnO2/montmorrillonite have been investigated. The results suggest that with pH increasing from 2 to 8, the stepwise exchange of zinc occurs on δ-MnO. and montmorrillonite in their mixture.At low pH zinc ions are bound on δ-MnO2, while at high pH, the exchange on montmorrillonite dominates the surface interaction in the mixture. The study demonstrates that the stepwise exchange and the heterogeneity of the binding sites on δ-MnO2 surface are the reason for the non-additive exchange. It is also shown that when δ-MnO2 amounts to 5 %, zinc exchange on sea sediments is controlled by 8-MnO2.     

Magnitude-frequency relationship of coastal sand delivery by a southern California stream

Coastal sand delivery by a stream in southern California is estimated based on a numerical model which stimulates unsteady flow, sediment transport, and the associated channel adjustments for a stream-delta system. An average annual sediment yield of 51,400 m³/yr is estimated for the San Dieguito River, which drains a semiarid watershed controlled by dams. Of the total sand delivery by the stream, 20.5 percent is contributed from floods greater than the 100-year flood; 17.6 percent from those between the 50- and 100-year events; 28.4 percent from those between the 25- and 50 year floods; and 33.5 percent from those smaller than the 25-year flood.     

Parameters of JONSWAP spectral model for surface gravity waves—II. Predictability from real data

Monte Carlo simulation of wave spectra was carried out to provide an assessment of JONSWAP spectral model and parameters. The simulation method is found to be satisfactory because (a) it excludes the spectral variability due to geophysical factors from the sampling errors in the spectral estimates and the statistical uncertainty in determining the model parameters; and (b) the simulated spectra can represent ideal spectral estimates where the sampling errors have been minimized by increasing the degrees of freedom of the spectra. The latter (b) allows both the magnitude of sampling errors to be evaluated and errors due to statistical uncertainty to be isolated. Thus, the stimulation study provides a useful error analysis to assess the JONSWAP spectral model and parameters. For instance, it is found from the results that the sampling errors could be as high as 20% while errors due to uncertainty in determining the model parameter could be as high as 17%. However, the overall errors may be reduced to the minimum of approx. 15% if the simulated spectra have 80 degrees of freedom and constant values of σ_a and σ_b i.e. σ_a = 0.07 and σ_b = 0.09. This implies that the maximum accuracy of 85% may be achieved in JONSWAP spectral model even though the α parameter has been underestimated by about 1.5%. The overestimated values of γ might come from the underestimated α and the biased φ_m estimator caused by the statistical uncertainty in the presence of a sharp spectral peak. Although the scale parameters (α and φ_m) exhibit smaller errors and variability than the shape parameters (ψ, σ_a and σ_b), they are more sensitive to the degrees of freedom of the spectra and their estimators are not better than the estimators of shape parameters. The simulation experiments have also shown that simulated spectra at 20–40 degrees of freedom contain a substantial amount of sampling errors. Therefore, the measured wave spectra at the same degrees of freedom (20–40) are not suitable and should not be used for evaluating the accuracy of any wave spectral model.     

Characterization of bacterial community structure in vestimentiferan tubeworm Ridgeia piscesae trophosomes

Terminal‐restriction fragment length polymorphisms (T‐RFLPs) were used to address the question whether there are multiple phylotypes of bacteria within the trophosome of the vestimentiferan tubeworm Ridgeia piscesae in addition to the known endosymbiont. Clone libraries were constructed to aid in the identification of the additional bacterial phylotypes. Individual R. piscesae specimens were collected from Juan de Fuca Ridge, Axial Caldera and Explorer Ridge, Magic Mountain. Clone library analyses revealed only one bacterial phylotype (expected R. piscesae endosymbiont) within the Explorer Ridge trophosomes. However, the Axial Caldera clone library revealed five operational taxonomic units (OTUs). Three of the resulting phylotypes detected (designated RAE) were putative thioautotrophic symbionts within the γ‐Proteobacteria which belonged to the anticipated endosymbiont group (RAE OTU 1), the Maorithyas hadalis symbiont II group (RAE OTU 3), and the Halothiobacillus group (RAE OTU 4). The remaining two phylotypes were most likely opportunistically derived. RAE OTU 5 was an α‐Proteobacterium within the Roseobacter group and RAE OTU 2 was within the Cytophaga–Flavobacterium–Bacteroidetes. T‐RFLP analyses revealed that all 15 trophosomes evaluated contained at least RAE OTUs 1 and 4. Five of the 15 trophosomes contained at least RAE OTUs 1, 3, and 4 and two of the trophosomes contained at least five RAE OTUs. Cluster analysis of the T‐RFLP data revealed three distinct clusters. The number of taxa within the trophosome may be an indication of the general health of the tubeworm. This study strongly suggests that we have discovered and identified more than one bacterial phylotype within the trophosome of vestimentiferan R. piscesae.     

Spatial and temporal variability of the ratios between the nitrate and phosphate concentrations in the Sea of Okhotsk

The relation between the nitrate and phosphate concentrations in the Sea of Okhotsk and the bordering waters of the Pacific Ocean were studied. The surveys were carried out in the autumn, spring, and summer of 2001–2002. For the deepwater part of the sea, the relation [NO^? ₃] = ((14.88 ± 0.07) × [PO^3? ₄] ? 5.46 ± 0.17) was found. The coefficients in the equation given are statistically different from those in the similar equation for the Pacific waters: [NO^? ₃] = (16.05 ± 0.15) × [PO^3? ₄]-(7.23 ± 0.36). In the northern part of the sea; on the shelf; in the slope area; and, especially, in the deep waters of the TINRO Depression, the linear dependence between the phosphate and nitrate concentrations was distorted. This feature was described in terms of nitrate deficiency. The maximum values of this deficiency were found in the near-bottom waters. The principal processes that might cause the nitrate deficiency were considered: the difference in the oxidation rates of the nitrogen and phosphorus organic compounds, the matter transfer between the continent and the sea, the different efficiency of the biogenic burial of nitrogen and phosphorus in the bottom sediments, and the denitrification in the upper layer of the bottom sediments. It was shown that the most probable cause of the nitrate deficiency was the denitrification. The loss of inorganic nitrogen owing to the supply of the waters of the Sea of Okhotsk to the Pacific Ocean was estimated as ～2.5 × 10¹¹ mol N/year.     

Circulation in the Gulf of Aqaba (Red Sea) during winter—spring

This study is devoted to oceanographic features of the semi-enclosed Gulf of Aqaba, Red Sea. The data were recorded in winter—spring 1999 on the R/V Meteor cruise leg 44/2. Temperature and salinity profiles were measured at six positions (I—VI). The shipboard NarrowBand Acoustic Doppler Current Profiler (NB ADCP) 150 kHz continuously recorded current profiles down to 350 m en route. The research revealed that the current near the Strait of Tiran front (position VI) represents a semidiurnal signal of an internal tide wave (∼12 h period; 0.2 ms⁻¹ amplitude) that might be generated by the barotropic tide at the sill of the Strait. A sequence of cyclonic and anticyclonic eddy pairs is found along the axis of the Gulf of Aqaba during winter-spring seasons. These sub-mesoscale signals are dominant above the main thermocline and might be caused by wind forcing and the narrowness of the Gulf; it might remain in other seasons with different dimensions in relation to the depth of thermocline. The total diameter of each pair was twice the baroclinic Rossby radius (R ≈ 10 km). A single anti-cyclonic eddy was observed in the upper 300 m in the northern tip of the Gulf with a diameter of about 5–8 km.     

Analysis of estuarine colour components during non-monsoon period through Ocean Colour Monitor

Simultaneous acquisition of water samples, radiance and irradiance measurements were carried out from 40 stations in the Mandovi–Zuari estuaries during February to May 2002. From the samples collected, inherent and apparent optical properties (IOP and AOP) such as absorption coefficient (a), upwelling diffuse attenuation coefficient (k_u) and subsurface reflectance (R) were derived. Using these optical properties, radiative transfer at each water column is examined. On the basis of the radiative transfer outcome, band-ratio algorithms are derived for three optically active substances (OAS), viz, chlorophyll-a, suspended sediment and coloured dissolved organic matter (CDOM). The respective algorithms are 670/555, 490/670 and 412/670 nm for chlorophyll-a, suspended sediment and CDOM. These algorithms are applied to Ocean Colour Monitor (OCM), onboard Indian Remote Sensing Satellite (IRS)-Polar Satellite Launch Vehicle (P4), scenes (digital data), to synoptically analyze these OAS. The synoptic analysis of OAS revealed different hydrodynamic characteristics of the estuaries during non-monsoon seasons.     

Rock magnetic records of the sediments of the eastern Arabian Sea: Evidence for late Quaternary climatic change

Rock-magnetic measurements along with grain size, acid-insoluble residue (AIR), organic carbon (OC), CaCO₃ and δ¹⁸O of the planktonic foraminifers of the sediments were determined for 15 gravity cores recovered from the western continental margin of India. Magnetic susceptibility (MS) values in the surficial sediments reflect the land-derived input and, in general, are the highest in terrigenous sediment-dominated sections of the cores off Saurashtra–Ratnagiri, followed by the sediments off Indus–Gulf of Kachchh and then Mangalore–Cape Comorin.

The down-core variations in mineral magnetic parameters reveal that the glacial sediments off the Indus are characterized by low MS values/S-ratios associated with high AIR-content, low OC/CaCO₃ contents and relatively high δ¹⁸O values, while those off SW India are characterized by low MS values/high S-ratio% associated with low AIR content, and relatively high OC, CaCO₃ and δ¹⁸O values. Conversely, the Early Holocene sediments of all cores are characterized by high MS values/S-ratio% associated with high AIR content, low OC, CaCO₃ contents and gradually decreased δ¹⁸O values. These results imply that during the Last Glacial Maximum (LGM), the cores off northwestern India received abundant continental supply leading to the predominance of eolian/fluvial sedimentation. In the SW region the influence of hinterland flux is less evident during this period, but convective mixing associated with the NE monsoon resulted in increased productivity. During the early Holocene intense SW monsoon conditions resulted in high precipitation on land, which in turn contributed increased AIR content/MS values in the continental margin sediments. A shallow water core off Kochi further suggests that the intense SW monsoon conditions prevailed until about 5 ka. The late Holocene organic-rich sediments of the SW margin of India were, however, subjected to early diagenesis at different intervals in the cores. Therefore, caution is needed when interpreting regional climatic change from down-core changes in sediment magnetic properties.