Seasonal and spatial variability of the content of suspended organic substances in the active layer of the Black Sea

On the basis of the generalized data of multiannual observations (1985–1994), we analyze the seasonal variability of the vertical and spatial distributions and composition (C_sos, N_sos, C_sos/cha, and C/N) of suspended organic substances (SOS) in the shelf zone and in the upper active layer of the abyssal part of the Black Sea. The results of our analysis enable us to conclude that only a narrow coastal band of the shelf in the northwest and west parts of the sea suffers to an extremely pronounced anthropogenic impact, which manifests itself in a significant increase in the mass of suspended organic substances. The formation of new organic substances and, hence, the mass of suspended organic substances in these regions attain the level of eutrophic waters in the late-spring and summer periods. In the open-sea region, the anthropogenic impact is less pronounced and the spatial distribution of suspended organic substances is determined by the general dynamics of waters and the intensity of phytoplankton production. Translated by Peter V. Malyshev and Dmitry V. Malyshev     

The study on highly expressed proteins as a function of an elevated ultraviolet radiation in the copepod, Tigriopus japonicus

The objective of the study was to analyze constantlyhighly expressed proteins as a function of elevated midultraviolet (UVB, 280?C315 nm) radiation in Tigriopus japonicus sensu lato (T. japonicus s.l). We also analyzed associations between kinetics of radiation avoidance, measured as a covered distance per time unit, and highly expressed proteins. The obtained results indicate an increase in T. japonicus s.l. mobility between the control (no radiation) and mild UV radiation levels (15 kJ·m^?2). Two-dimensional gel electrophoresis combined with MALDI-MS-MS resulted in 2D protein map comprising of 686 protein spots, of which 19 were identified as highly expressed proteins across all experimental conditions. Obtained results indicate that calpain, vitellogenin, and collagenase are housekeeping protein that are expressed at a constant level independently of environmental changes and that adoption of a locomotive system for the avoidance of a UV source may be, at least partially, supported by hepatopancreas-driven metabolism.     

Sunken wood habitat for thiotrophic symbiosis in mangrove swamps

Large organic falls to the benthic environment, such as dead wood or whale bones, harbour organisms relying on sulfide-oxidizing symbionts. Nothing is known however, concerning sulfide enrichment at the wood surface and its relation to wood colonization by sulfide-oxidizing symbiotic organisms.In this study we combined in situ hydrogen sulfide and pH measurements on sunken wood, with associated fauna microscopy analyses in a tropical mangrove swamp. This shallow environment is known to harbour thiotrophic symbioses and is also abundantly supplied with sunken wood. A significant sulfide enrichment at the wood surface was revealed. A 72 h sequence of measurements emphasized the wide fluctuation of sulfide levels (0.1–>100 μM) over time with both a tidal influence and rapid fluctuations. Protozoans observed on the wood surface were similar to Zoothamnium niveum and to vorticellids. Our SEM observations revealed their association with ectosymbiotic bacteria, which are likely to be sulfide-oxidizers. These results support the idea that sunken wood surfaces constitute an environment suitable for sulfide-oxidizing symbioses.     

Isotopic,trace element and nutrient characterization of coastal waters from Ubatuba inner shelf area,south-eastern Brazil

Stable isotopes, tritium, radium isotopes, radon, trace elements and nutrients data were collected during two sampling campaigns in the Ubatuba coastal area (south-eastern Brazil) with the aim of investigating submarine groundwater discharge (SGD) in the region. The isotopic composition (δD, δ¹⁸O, ³H) of submarine waters was characterised by significant variability and heavy isotope enrichment. The stable isotopes and tritium data showed good separation of groundwater and seawater groups. The contribution of groundwater in submarine waters varied from a few % to 17%. Spatial distribution of ²²²Rn activity concentration in surface seawater revealed changes between 50 and 200 Bq m⁻³ which were in opposite relationship with observed salinities. Time series measurements of ²²²Rn activity concentration in Flamengo Bay (from 1 to 5 kBq m⁻³), obtained by in situ underwater gamma-spectrometry showed a negative correlation between the ²²²Rn activity concentration and tide/salinity. This may be caused by sea level changes as tide effects induce variations of hydraulic gradients, which increase ²²²Rn concentration during lower sea level, and opposite, during high tides where the ²²²Rn activity concentration is smaller. The estimated SGD fluxes varied during 22–26 November between 8 and 40 cm d⁻¹, with an average value of 21 cm d⁻¹ (the unit is cm³/cm² per day). The radium isotopes and nutrient data showed scattered distributions with offshore distance and salinity, which implies that in a complex coast with many small bays and islands, the area has been influenced by local currents and groundwater–seawater mixing. SGD in the Ubatuba area is fed by coastal contaminated groundwater and re-circulated seawater (with small admixtures of groundwater), which claims for potential environmental concern with implications on the management of freshwater resources in the region.     

Analysis of second-order resonance in wave interactions with floating bodies through a finite-element method

A time-domain method is employed to analyse the resonant oscillations of the liquid confined within the two floating bodies. The velocity potentials at each time step are obtained through a finite-element method (FEM) with quadratic shape functions. The matrix equation of the FEM is solved through an iteration. The radiation condition is satisfied through a combination of the damping zone method and the Sommerfeld–Orlanski equation. A detailed analysis is made for two rectangular floating cylinders undergoing forced oscillation. The first-order potential reveals the resonant behaviour of the wave motion at certain frequencies ω_i, which is similar to sloshing in a tank. More interestingly, the second-order theory further reveals that when the oscillation frequency is at ω_i/2 or half of the resonant frequency, no first-order resonance is observed as expected, but the second-order resonant motion becomes evident, which does not seem to have been extensively investigated so far. Detailed results for two rectangular cylinders are provided to show some insights into the resonant effect due to the interaction between the bodies. The first- and second-order resonant phenomena have been observed and the result has shown that the second-order components have significant influence on the wave and force in some cases, especially at the second-order resonance.     

Particle-Velocity-Field Difference Smoothing for Coherent Source Localization in Spatially Nonuniform Noise

This communication considers the problem of estimating 2-D directions of arrival (DOAs) of multiple coherent signals under spatially nonuniform noise (spatially inhomogeneous temporary white noise) using an array of vector hydrophones. A novel preprocessing method called particle-velocity-field difference smoothing (PVFDS) is proposed. The key idea underlying the PVFDS is to remove the spatially nonuniform noise by using the matrix difference of pairs of particle-velocity data correlation matrices, and to decorrelate the coherent signals by summing these difference correlation matrices. Unlike most of other existing preprocessing techniques, such as spatial smoothing and forward–backward averaging, the PVFDS processing does not decrease the array aperture. For arbitrary array geometries, the PVFDS can resolve up to four coherent signals, and for centro–symmetric arrays, forward–backward averaging can double this number to eight. Monte Carlo simulations illustrate that the PVFDS-based eigenstructure algorithms can offer better performance than the particle-velocity-field smoothing (PVFS)-based counterparts.      

A Study on the Distribution of Wave Phases

Probability distributions of wave phases in association with distributions of surface elevations arestudied with wave records.Wave records of different nature are used for comparison.These are surface fluc-tuations acquired during wind wave flume experiments,representing wave generation under strong wind:andwave records measured in the northern part of Taiwan for waves in natural environments.Three probabilitymodels,the unifrom distribution,the beta distribution,and a model from Tayfun and Lo(1989)are adoptedto study the possible distributions of wave phases.It is found that when surface elevations become skewed,wave phases deviate from the usually assumed uniform distribution and a better model would be the beta dis-tribution.     

以哈维氏弧菌(Vibrio harveyi)为重点的鱼类细菌病原的诊断与控制(英文)

作者对鱼类细菌病原的诊断与控制作了较全面的综述。细菌病原诊断技术包括酶联免疫吸附技术（ＥＬＩＳＡ）及蛋白印迹法（Ｗｅｓｔｅｒｎｂｌｏｔｉｎｇ）。细菌病原控制技术包括化学疗剂的应用,有益微生物的应用,营养添加剂,β－葡萄糖苷增强免疫抗病力,及免疫保护作用等。     

North Brazil current: vertical structure

On the basis of the data ofin situ measurements of the velocities of currents and basic hydrophysical parameters (such as temperature and salinity) carried out during Cruise 41 of the R/VAkademik Vernadsky, we analyze the structure of the North Brazil Current near the continental slope and in the equatorial abyssal part of the ocean in winter, establish the regularities of changes in the current velocity with depth, and compare the structures of the North Brazil and Guiana Currents. Translated by Peter V. Malyshev and Dmitry V. Malyshev