Role of the small-size fraction of mesozooplankton in the pelagic community of the northeastern part of the Black Sea in the autumn

The role of the small-size (SF; 0.1–0.5 mm) and large-size (LF; 0.5–20.0 mm) fractions in the biomass and abundance of mesozooplankton (0.1–20.0 mm) was assessed using the database of samples obtained during the cruises of RV Akvanavt in the northeastern Black Sea in November 2000 and October 2006. The mesozooplankton was collected by means of Juday nets (37/50, filtering gauze 160 μm) and Niskin bottles in two areas: (1) the shelf and continental slope (30–1480 m depth) and (2) the deep sea (depths of more than 1500 m). The plankton net was considerably less effective in collecting the SF of the mesozooplankton (by a factor of 30–36) than the Niskin bottles. When comparing the SF and LF, we estimated the abundance and biomass of the SF in the samples obtained with the Niskin bottles. The abundance of the SF in the deep-sea area was 2.5 times lower compared to the shelf and continental slope, and the LF abundance was 5.0 times lower in the same way. The abundance of the SF constituted 88% of the total mesozooplankton on the shelf and continental slope, and 78% in the deep-sea area. The biomass of the SF was higher as well on the shelf and continental slope. Meroplankton played a significant role in the SF zooplankton abundance (0.5 × 10³ + 0.16 ind. m⁻³) in this area. The SF grazing impact was 10% of the total mesozooplankton grazing on the shelf and continental slope, and 17% in the deepsea area. Appendicularia and nauplii of copepods had the greatest contribution to the mesozooplankton grazing among the SF group.     

台湾以东黑潮锋的中尺度过程研究

采用海洋再分析结果,研究了海洋涡旋和锋面波动对台湾以东黑潮锋的影响,结果表明,Rossby波第一斜压模态形成的冷涡(暖涡),减弱(增强)台湾以东黑潮温度锋强度,减小(加大)锋的宽度.在再分析结果中,捕获到1991年1-2月台湾以东的一次黑潮锋面波动.锋面波动的波槽(波脊)到达时,该温度锋强度减弱(增强),宽度和厚度减小...     

Characterizing the influence of tide on the physico-chemical parameters and nutrient variability in the coastal surface water of the northern Bay of Bengal during the winter season

The spatial distribution of physico-chemical parameters(sea surface temperature(SST), p H, sea surface salinity(SSS), dissolved oxygen(DO) and Secchi depth) along with filterable nutrients(dissolved inorganic nitrate(DIN),dissolved inorganic phosphate(DIP) and reactive silicate(DSi)) are measured in the winter months of November,December, January and February for four consecutive years from 2009–2010 to 2012–2013 on the shallow continental shelf(20 m bathymetry) of the coastal waters(up to 18 km away from shoreline) of the northern Bay of Bengal(n Bo B) during the highest high tide(HHT) and lowest low tide(LLT) hours for the first time. The variability of the coastal biogeochemical environment is assessed during the HHT and LLT hours and for this purpose, seawater samples are collected from seven different locations of a transect in the coastal region. Physicochemical parameters(except SST) show significant difference in magnitude during the HHT and LLT hours respectively. p H, SSS and DO are found to increase in the HHT hours and vice-versa. The data reveal that during the LLT hours, a relative increase of freshwater input in the n Bo B can have elevated the nutrient concentration compared with that observed during the HHT hours. The ratio of nutrient concentration is found to deviate significantly from the Redfield ratio. The abundance of DIP is much higher compared with that of DIN and DSi.The anthropogenic sources of DIP from the upstream flow(especially the domestic effluent of several metropolises) can be mainly attributed behind such an observation. In order to characterize and establish the trend of such variation in such an important bio-climatic region, long-term and systematic ecosystem monitoring in the coastal water of the n Bo B northern Bay of Bengal should be carried out throughout the year.     

Satellite observations of the partial pressure of carbon dioxide in the surface water of the Huanghai Sea and the Bohai Sea

Based on 5 831 continuous in situ measurements of the partial pressure of carbon dioxide on the sea surface p(CO2),related parameters of the sea surface temperature(SST) and chlorophyll-a(Chl a) concentration in 2010 winter,spring and summer of the Huanghai Sea and the Bohai Sea,the inherent relations among them are investigated preliminarily.This study reveals that the seasonal variability of SST and Chl a concentration has a significant influence on p(CO2).The authors have proposed a new algorithm to estimate p(CO2) from SST and Chl a concentration measurements.Compared with the vessel data,the root mean square error(RMSE) of p(CO2) retrieved by using the new model is 13.45 μatm(1atm=101.325 kPa) and the relative error is less than 4%.Then,SST and Chl a concentration data observed by satellite are used to retrieve p(CO2) in the Huanghai Sea and the Bohai Sea;and a better accuracy can be obtained if the quality control for sea surface chlorophyll-a concentration observed by satellite is used.The RMSE of retrieved p(CO2) data with quality control and that without quality control are 15.82 μatm and 31.74 μatm,respectively.     

Extending the versatility of the Bullard heat probe

A versatile probe for simultaneous studies of heat flow and near-bottom water parameters has evolved through modifications of the Bullard heat probe frame. Suitable sensor arrays have been used with this instrument to study (1) heat flow through the ocean floor, (2) water column temperature structure, (3) near-bottom current speeds, and (4) the differential cooling of water-column temperature sensors placed in a current speed gradient.Some of the advantages of such a modified Bullard probe are: (1) several parameters, including heat flow, can be measured across the sediment-water interface simultaneously, (2) the instrument frame is rigidly pinned to the ocean floor during measurement, permitting true Eulerian measurement in the water column with no effects of ship movement, swaying moorings or cable oscillation, and (3) the device is inexpensive and simple.     

北太平洋副热带海洋环流强度异常对长江中下游夏季降水的影响

利用SODA资料和ECCO资料计算得到的北太平洋副热带海洋环流强度,和国家气候中心整编的中国160站逐月降水资料,结合NCEP/NCAR再分析资料和Hadley中心海表面温度资料,分析了1970－2007年海洋环流强度异常同期的大尺度大气环流异常特征及对中国东部夏季降水的影响。结果表明:海洋环流强度变化与长江中下游地区降水存在密切的反相关。环流强度异常可以通过影响西太平洋副热带高压的南北位置异常进而影响长江中下游降水。海洋环流偏弱时,副高位置偏南,长江中下游地区受气旋性环流异常影响,来自副高西北侧的强西南水汽输送至此,在该地区形成强水汽辐合中心,同时伴随上升运动加强和对流的加强,进一步导致该地区降水偏多;当海洋环流偏强时,西太平洋副高位置偏北,长江中下游地区受反气旋性环流异常影响,伴随辐散下沉及水汽辐散,导致该地区降水偏少;海洋环流强度异常导致的中纬度海区海表面温度异常,可能是导致副高南北位置异常的主要原因。     

中国沿海三疣梭子蟹的遗传结构和亲缘关系分析

应用CLUSTAL X 1.81对位排序软件和Molecular Evolutionary Genetics Analysis (MEGA) Version 3.1系统发育相关分析软件包,分析了渤海、黄海和东海不同群体的三疣梭子蟹mtDNA D-loop片段序列,(不包括引物)D-loop序列(不包括引物)长约1 241 bp,该片段AT、GC平均含量分别为75.8%和24.2%,AT含量均明显高于GC含量,种群间的遗传距离平均为0.025.依据D-loop序列,应用邻接法(NJ)、最小进化法(ME)及最大简约法(MP),构建中国沿海三疣梭子蟹亲缘关系的系统发生树,MP、NJ和ME树中所显示的三疣梭子蟹亲缘关系基本一致.NJ和ME树中来自东海的XM1与DT5聚为姊妹群;来自渤海的PL1与来自东海的YT1聚为姊妹群;来自东海的DT3与来自黄海的DD1聚为姊妹群,再与来自渤海的PJ1相聚形成一个单系;来自东海的ZS1与来自黄海的QD1聚为姊妹群;来自东海的DT4与来自黄海的YC1相聚,再与来自东海的YT2,YT3相聚.在MP树中,来自黄海的YC1与来自东海的DT4相聚为姊妹群,再与YT2相聚;来自渤海的PL1与来自东海的YT1聚为姊妹群;来自东海的XM1与DT5聚为姊妹群;来自东海的DT3与来自黄海的DD1聚为姊妹群,再与来自渤海的PJ1相聚;来自东海的ZS1与来自黄海的QD1聚为姊妹群;这些群最后再与来自东海的YT3相聚.结果显示中国沿海各海区三疣梭子蟹种群间存在明显的基因交流,亲缘关系的远近并不以海区划分和地理位置的远近为依据.洄游和长期以来跨海区的捕捞作业可能是三疣梭子蟹种群间基因交流的根本原因;蓬勃发展的三疣梭子蟹人工养殖和放流也会导致亲蟹和苗种跨海区交流,对三疣梭子蟹种质资源的保护将产生巨大影响.     

台湾以东黑潮锋的中尺度过程研究

采用海洋再分析结果,研究了海洋涡旋和锋面波动对台湾以东黑潮锋的影响,结果表明,Rossby波第一斜压模态形成的冷涡(暖涡),减弱(增强)台湾以东黑潮温度锋强度,减小(加大)锋的宽度.在再分析结果中,捕获到1991年1-2月台湾以东的一次黑潮锋面波动.锋面波动的波槽(波脊)到达时,该温度锋强度减弱(增强),宽度和厚度减小...     

The study of the Kuroshio in the East China Sea and the currents east of the Ryukyu Islands

In this study, the inverse method is used to compute the Kuroshio in the East China Sea and southeast of Kyushu and the currents east of the Ryukyu Islands, on the basis of hydrographic data obtained during September-October, 1987 by R/V Chofu Maru. The results show that: (1)A part of the Taiwan Warm Current has a tendency to converge to the shelf break; (2) the Kuroshio flows across the section C3 (PN) with a reduced current width, and the velocity of the Kuroshio at the section C3 increases and its maximum current speed is about 158 cm/s, and its volume transport here is about 26×106m3/s; (3) the Kuroshio has two current cores at the sections C3 (PN) and B2 (at the Tokara Strait); (4) the currents east of the Ryukyu Islands are found to flow northward over the Ryukyu Trench during September-October, 1987. The velocities of the currents are not strong throughout the depths. At the section C2 east of the Ryukyu Islands, the maximum current speed is at the 699 m levei and its magnitude is 25 cm/s, and i     

渤海、黄海沿岸主要港湾大振幅假潮成因的天气学分析

对渤海、黄海主要港湾发生的振幅大于50cm(龙口港湾取振幅大于80cm)的65次假潮过程与地面天气图进行对比分析,着重分析了伴随大振幅假潮过程的天气形势.分析结果表明:(1)龙口港湾22次大振幅假潮中有19次与雷暴天气(其中有3次伴随有飑线,1次还伴有龙卷)有关,2次与大风天气有关,1次由外海雷暴引起;因此得出雷暴、飑线是引起大振幅假潮的主要原因;雷暴强弱和持续时间长短变化,导致假潮振幅大小及持续时间长短变化;雷暴的季节变化引起大振幅假潮的季节变化;雷暴发生的局地性导致假潮出现的局地性;雷暴传播方向的不同引起大振幅假潮的周期不同.(2)北方气旋型和江淮气旋及西南倒槽型这两种天气类型有利于产生雷暴,并导致大振幅假潮的发生.这两类型分别占62个例的468%和177%.     

太平洋海温异常对南海西南季风建立早晚的影响——数值模拟研究

利用9层15波全球大气环流谱模式研究了太平洋海温异常对南海西南季风建立早晚的影响作用.结果表明:西-中太平洋海温异常数值试验结果最能反映出南海西南季风爆发早、晚年4～5月份大气环流的差异特征.数值试验结果显示:西太平洋海温正(负)异常可导致西太平洋副高减弱(加强);中太平洋海温正(负)异常主要使得中太平洋上空的洋中槽减弱(加深);东太平洋海温正(负)异常可造成东太平洋赤道两侧高层环流产生反气旋性(气旋性)变化,孟加拉湾-南海-西太平洋热带地区出现东风(西风)异常,西太副高加强(减弱).可见西太平洋海温异常和东太平洋海温异常都可以对副高强弱变化产生明显影响,从而对南海西南季风建立早晚产生影响,只不过西太平洋海温异常的影响作用更为显著.西太平洋正(负)海温异常与中太平洋负(正)海温异常经常是同时出现的,其激发出的与向东传的Kelvin波和向西传的行星波相联系的环流异常为南海季风建立早(晚)提供有利的条件,因而这一海温分布型是影响南海西南季风建立早晚的重要影响因子.     

Diagnostic calculation of the upper-layer circulation in the South China Sea during the winter of 1998

On the basis of hydrographic data obtained in November 28 to December 27, 1998 cruise, the calculation of the circulation in the South China Sea (SCS) is made by using the P-vector method, in combination with SSH data from TOPEX/ERS-2 analysis. For study of the dynamical mechanism, which causes the pattern of winter circulation in the SCS, the diagnostic model (Yuan et al., 1982; Yuan and Su, 1992) is used to simulate numerically the winter circulation in the SCS. The following results have been obtained. (1) The main characteristics of the circulation systems in the central SCS are as follows: A coastal southward jet in winter is present at the western boundary near the coast of Vietnam; there is a stronger cyclonic circulation with a larger horizontal scale east of this coastal southward jet and west of 114°E; there is a weaker anti-cyclonic circulation in the central part of eastern SCS; there is a stronger and northeastward flow opposing the northeasterly monsoon between above a stronger cyclonic c     

Comparison of the satellite and ground-based measurements of the hydrogen fluoride content in the atmosphere

Satellite and ground-based measurements of the hydrogen fluoride (HF) total content (TC) are analyzed and compared. The HF profiles measured with an FTS device on the ACE satellite are used to calculate the TC and compare it with the ground-based measurements near St. Petersburg in 2009–2011. A comparison indicated that the seasonal variations in HF TC based on two independent measurements are in good qualitative agreement. Rare (nine) cases of direct comparison between two measurement types coordinated with respect to time (during the day) and site (no farther than 500 km) gave the following characteristics: the average difference is 8% and satellite data predominate over ground data; the standard deviation of a difference is 7%. In two cases of close measurement pairs (closer than 200 km), a comparison gave differences of 1 and 7%. The statistical characteristics of differences between two measurement types are in good agreement with the independent comparison of the ACE-FTS HF TC measurements with the NDACC network data.     

Evaluation of the ecological state of the Sea of Japan and the Sea of Okhotsk using the DNase test system

A study of the state of the Russian coastal marine ecosystems of the Sea of Japan (the Tumen River mouth) and the Sea of Okhotsk (the eastern shelf of Sakhalin Island and the Sakhalin Gulf) and Kraternya Bight (Yankich Island, Kuril Islands) was carried out during the 29th expedition of the R/V Akademik Oparin. A highly sensitive express analysis using the DNase of the Strongylocentrotus intermedius sea urchin was utilized in order to evaluate the quality of the natural marine water of the areas experiencing different degrees of anthropogenic impact. The marine water quality was evaluated according to the degree of the DNase inhibition in the samples. The presence of ecological stress was shown at the aforementioned sites excluding Kraternya Bight. The method allows the fast (1 hour) analysis of the pollution of marine areas and, coupled with data on the hydrological, hydrochemical, and microbiological studies of water samples, provides the possibility to make an ecological forecast.     

On the Relationship between the Characteristics of the Annual Variations of the Virtual Height of the Ionospheric Sporadic E Layer with the Seasonal Rearrangements of the Stratomesospheric Circulation

Izvestiya, Atmospheric and Oceanic Physics - Analysis of the temporal variations of the virtual heights of the sporadic E layer (h?ES) determined from ionograms with increased accuracy (1...     

Changes in the diet and feeding of the hake Merluccius merluccius at the shelf-break of the Balearic Islands: Influence of the mesopelagic-boundary community

Short spatio–temporal variations in the feeding intensity and the diet of the European hake, Merluccius merluccius, together with the abundance of their potential prey were studied between August 2003 and June 2004 at two locations, northwest (Sóller) and south (Cabrera), off the island of Mallorca (Balearic Islands, Western Mediterranean) at depths between 150 and 750 m. The two areas present different oceanographic conditions. Hake was mainly distributed along the shelf-slope break and the upper slope (between 166 and 350 m) where recruits (TL<18 cm) were dominant. The hake's diet varied as a function of size. Recruits fed mainly on micronektonic prey, and the diet was influenced primarily by seasonality, with two dietary patterns (identified by MDS analyses) corresponding to August–September 2003 (summer) and to November 2003/February–April 2004 (autumn–winter). The summer pattern was consistent with a thermally stratified water column, while November and April were consistent with homogenized temperature and salinity throughout all the water column. The main prey of recruits were the euphausiid Meganyctiphanes norvegica and the midwater fish Maurolicus muelleri in autumn–winter and myctophids (mainly Ceratoscopelus maderensis) in summer. In contrast to recruits, the geographic factor (NW vs. S) was the main factor influencing the diets of post-recruits (TL between 18 and 21.9 cm) and adults (TL?22 cm). Hake recruits (and to a lesser extent post-recruits) and their preferred prey occupied different depth ranges during daylight periods. Meganyctiphanes norvegica and Ceratoscopelus maderensis were, for instance, distributed as much as 500 m deeper than hake that had eaten them. All these trends were especially obvious at NW, an area with a more abrupt slope and with a greater influence by northern winter intermediate water (WIW) inflow in early spring than the S area. These factors probably enhanced micronekton aggregation in April, when feeding intensity (stomach fullness) increased among recruits and post-recruits only at NW. All these factors may have a crucial role in the diet, distribution and probably recruitment success of small hake. Biological factors were also important in trophic shifts in the diet and feeding of hake. Multi-linear regression models pointed to a trend of higher fullness with higher hepato-somatic index (HSI). Therefore greater food consumption by hake may enhance its metabolic condition. Within the framework of shelf-break and slope ecology, we show how the ‘boundary’ mesopelagic community inhabiting the middle slope sustains the trophic requirements of hake, a species distributed at shallower depths along the shelf-slope break. Mesopelagic euphausiids and myctophids are often found in the diets of shelf-break fish. Because the boundary mesopelagic community is distributed worldwide, the high levels of fish biomass often found at shelf-slope breaks could be sustained trophically by deeper, offshore mesopelagic communities, an inverse energy transfer from deep to shallow-water marine ecosystems.     

A note on the extremal properties of the morison equation

The extremal properties of the Morison equation F(t) = X′(t) + X(t)|X(t)|; for the force on a circular pile in a fluid, are derived by means of a Slepian model for the behaviour of X(t) around its local maxima. The behaviour of X′(t) near large maxima of X(t) is almost deterministic, and hence there is a simple relation between the maxima in X(t) and those in F(t).     

Spectral classification of water masses under the influence of the Amazon River plume

The large amount of dissolved and particulate material discharged by the Amazon River into the Equatorial Atlantic Ocean cause distinct spectral response of its waters as compared to the nearby ocean waters. This paper shows the application of K-means clustering algorithm for classifying water masses in the region under the Amazon River plume influence according to their spectral behavior. Salinity and temperature data from 67 oceanographic stations were related to Sea-viewing Wide Field-of-view Sensor (SeaWiFS) remote sensing reflectances values and the following bio-optical products:(i) chlorophyll-a concentration, (ii) water attenuation coefficient and (iii) absorption coefficient for dissolved and detrital material. Four different water masses were identified such as:(1) oceanic water, (2) intermediate oceanic water, (3) intermediate river plume water and (4) Amazon River plume water. The spectral behavior of these water masses allowed concluding that the main active optical component of the waters in the region is the colored dissolved organic matter originated mostly from the Amazon River.     

Use of a problem-oriented database for statistical analysis of the hydrochemical characteristics of the redox layer of the Black Sea

A problem-oriented database (PODB) was developed for the statistical analysis of the hydrochemical characteristics of the redox layer of the Black Sea. The paper describes the features of the PODB, including the algorithm of interpolation and the location of the levels of the appearance and disappearance of hydrochemical parameters (the so-called onset levels) based on Akima’s spline. The application of the PODB allowed us to obtain a series of biogeochemical estimates, in particular, (1) to reveal the constancy of the vertical gradients of the hydrochemical parameters at selected density levels; (2) to calculate the seasonal variability of the degree of manifestation of the phosphate minimum in the near-shore and open sea areas; and (3) to calculate the interannual variability of the level of the disappearance of the hydrogen sulfide, ammonium, total manganese, and methane, as well as the oxygen content in the cold intermediate layer, and to find out their relations with the climatic variations.     

Relationship between the path of the Kuroshio in the south of Japan and the path of the Kuroshio Extension in the east

A relationship between paths of the Kuroshio and Kuroshio Extension (KE) is investigated, using the satellite-derived altimetry dataset of 1993–2008. When the Kuroshio takes the nearshore nonlarge meander path or typical large meander path and resultantly goes through the deeper channel (about 2500 m) of the Izu-Ogasawara Ridge, the KE path adopts a relatively stable state with the two quasi-stationary meanders. On the other hand, when the Kuroshio takes the offshore nonlarge meander path and then passes over the shallower part of the Ridge (about 1000 m), the KE path tends to be convoluted, i.e., an unstable state.