On the role of abiogenic factors in the bioaccumulation of heavy metals by the hydrothermal fauna of the Mid-Atlantic Ridge

The distributions of Fe, Mn, Zn, Cu, Ni, Co, Cr, Pb, As, Ag, Cd, Se, Sb, and Hg in 128 samples of tissues of the organisms that inhabit hydrothermal vent fields of the Mid-Atlantic Ridge (Menez Gwen, Snake Pit, and Rainbow) depending on the abiotic environmental parameters were studied. The majority of the elements studied showed direct correlations between their concentrations in the fluids released and in the tissues of hydrothermal organisms. A higher degree of bioaccumulation of metals was revealed in the Bathymodiolus mussels and Rimicaris shrimps from the Rainbow hydrothermal vent field as compared to their analogues from Menez Gwen and Snake Pit. This corresponds to the maximum concentrations of the majority of the metals studied in the Rainbow high-temperature hydrothermal fluids. The highest degree of bioaccumulation of heavy metals was found in gills of the symbiotrophic mussels Bathymodiolus and in maxillipeds of the ectosymbiotic shrimps Rimicaris, i.e., in the organs that function in dependence on chemosynthetic bacteria. Within the Rainbow vent field, the shrimps, which inhabit in biotopes with more high-temperature conditions and therefore are more strongly subjected to the influence of fluids, were found to contain higher metal contents than mollusks. The Fe-Mn hydroxide films that cover mussel shells might serve as important reservoirs of other metals related to Fe and Mn.     

中印度洋脊Edmond热液区成矿流体属性与来源:来自流体包裹体和He-Ar同位素的证据

To understand the source and nature of the ore-forming fluids of the Edmond hydrothermal field on the Central Indian Ridge, we studied the He-Ar isotope composition and fluid inclusions of the hydrothermal precipitates.Our results show that the sulfide samples contain noble gases He, Ne, Kr, and Xe with their abundances in between those of air-saturated water(ASW) and mid-ocean ridge basalt(MORB). The ~3He/~4He ratio varies from1.3 to 8.7 R_a(n=10, average: 5.1 R_a), whereas the ~(40)Ar/~(36) Ar ratio is from 285.3 to 314.7(n=10, average: 294.8). These results suggest that the He was derived from a mixture of MORB with variable amounts of seawater, but the Ar in the ore-forming fluids trapped in the sulfides is predominantly derived from seawater. The fluid inclusions of barite have a wide range of homogenization temperatures and salinities varying from 163°C to 260°C and 2.6 wt%to 8.5 wt% Na Cl equiv., respectively. It is suggested that the ore-forming fluids were produced by phase separation, which agreed with the present-day vent fluid study.     

Studying the sea surface slopes using an array of wave gauge sensors

The deviations of the marine surface slope spectra (measured using an array of wave gauge sensors) from the theoretical estimates obtained using the linear spectral model of the wave field are analyzed. It has been indicated that the average measured full slope spectra (the sum of the slope component spectra in the orthogonal directions) is higher than the theoretical estimates by 6% at frequencies from the surface wave spectral peak (f _m ) to 4.5 f _m . The difference between the measured and theoretical estimates of the full slope spectrum rapidly increases at frequencies of f < f _m . At f _m ≈ 0.75 f _m , the average measured full slope spectrum is higher than the theoretical estimate by a factor of more than 5.     

Features of the spatial distribution of phytoplankton in Nhatrang Bay of the South China Sea during the rainy season

The species composition, phytoplankton abundance, and relative yield of the variable fluorescence (F _v /F _m ) were determined in the mesotrophic Nhatrang Bay in October–November of 2004. The species diversity (250 taxonomic units) and heterogeneity of the phytoplankton structure were high. With respect to the number of species and their abundance, diatoms prevailed. In selected parts of the bay, dinoflagellates dominated. The mean biomass in the water column under 1 m² (B _t ) varied from 2.3 to 64.4 mg C/m³ being 31.0 mg C/m³ on average. The values of B _t were the lowest at the stations nearest to the river mouth. Seaward, B _t increased. The values of B _t increased with depth at some stations and decreased at others. In the surface sea layers, the biomass was lower than that in the underlying waters. The values of F _v /F _m ranged from 0.10 to 0.64 (at a mean value of 0.49). The lowest values of F _v /F _m were observed in the area close to the seaport. Over the greater part of the bay, the values of F _v /F _m were higher than 0.47. Such values are indicative of the relatively high potential photosynthetic activity of the phytoplankton. The abundance and species diversity were higher than those in the dry season (March–April).     

Features of the atmospheric boundary layer block for three versions of the WAM wind wave model

The estimated characteristics of the atmospheric boundary layer, obtained by the simulation of wind wave fields using three versions of the WAM numerical model are compared with the well-known empirical dependences of drag coefficient C _d on wind speed U ₁₀ and wave age A, as well as with the dependence of dimensionless roughness height z _n on inverse wave age u*/с р. Calculations carried out for several years in the areas of the Pacific and Indian oceans, based on the ERA-interim and CFSR wind reanalyses have shown good agreement between the model and empirical dependences C _d (U ₁₀) and C _d (A). The range of estimated variability for z _n (u*/с _р ) has been found to be significantly less than empirical. It has been also found that estimated values of wind speed U _10W (t) are overestimated from 5 to 10% in all versions of WAM models compared with the input wind reanalysis U _10R (t) at the moments of appearance maximum values of wind U _10R (t). The reasons for the established features of the WAM model and their dependence on the model version are discussed.     

Phytoplankton production characteristics in the Eastern Atlantic and Atlantic sector of the Southern Ocean in October–November 2004

Production parameters of surface phytoplankton were measured along three transects: La Manche-Cape Town (I); Cape Town-54°S (II); 0°-49°W (along 54°S) (III). The Canary upwelling waters were most productive along transect I, where the surface chlorophyll a (Chl ₀) and the surface primary production (PP ₀) were as high as 4.3 mg/m³ and 173 mg C/m³ per day, respectively. Mosaic patterns in the distribution of these parameters were recorded in the northeastern regions of the South Subtropical Anticyclonic Gyre (Chl ₀ = 0.03–0.35 mg/m³; PP ₀ = 1.6–12.6 mg C/m³ per day). Along transect II, the average twofold southward increase in Chl ₀ (from 0.2 to 0.4 mg/m³) and the concurrent decline of the phytoplankton assimilation activity ( AN ₀) resulted in deviations from typical latitudinal changes inPP ₀. At most sites, PP ₀ values varied between 6 and 15 mg C/m³ per day. Negligible changes in Chl ₀ (0.36–0.85 mg/m³), PP ₀ (8–19 mg C/m³ per day), and AN ₀ (0.7–1.6 mg C/mg chl a per hour) were registered for the oceanic waters along transect III. Along all the transects, PP ₀ depended on Chl ₀ to a greater extent than AN ₀. The values of the latter parameter were largely determined by the water temperature and showed a slight correlation with the insolation. Along transect II, the integrated primary production (PP _int) and the layer-integrated chlorophyll a in the upper 200 m (Chl _0–200) generally varied from 180 to 360 mg C/m² per day and from 30 to 70 mg/m², respectively. In the Polar Front region, an increase in Chl _0–200, PP _int, Chl ₀, and PP ₀ up to respective values of 190 mg/m², 520 mg C/m² per day, 1.2 mg/m³, and 32 mg C/m³ per day was observed. A comparison of the water column (0–100 m) stability with the vertical distribution of the primary production and chlorophyll content along transect II implies that the thick (>100 m) upper mixed layer (UML) formed in response to the strong water cooling and wind forcing was largely responsible for the limited primary production in the Subantarctic and Antarctic regions. The large UML thickness resulted in an intense removal of plant cells from the photosynthetic layer and light starvation of a significant (up to 60%) part of the phytoplankton community.     

Estimating the parameters of pulsed sources from data on acoustic waves recorded in the atmosphere

The possibility of estimating the parameters of surface pulsed sources from data on acoustic waves recorded in the atmosphere is studied. Experimental values are given for peak pressure P ₊ of recorded acoustic signals, wave-profile area S ₊ in their positive phase, and length t ₊ of this phase, and the approximations of these parameters are obtained within wide ranges of source energy 10^–3 < E < 10¹⁰ kg TNT and scaled distances 1 < R/E ^1/3 < 4 × 10⁴ m/kg^1/3. Conventional methods of estimating the acoustic energy E according to data obtained from acoustic measurements in the atmosphere are analyzed, and ways to improve their accuracy are proposed. The influence of the type of explosions on the parameters P ₊, S ₊, and t ₊ of acoustic signals at long distances R/E ^1/3 > 500 m/kg^1/3 from explosions is shown.     

Sources and distribution of allochthonous organic matter in surface sediment from the Seomjin River to the southern inner shelf of Korea

The spatial distributions of δ¹³C, δ¹⁵N, and n-alkanes were investigated to determine the source and transportation of allochthonous organic matter from the mouth of the Seomjin River to the southern inner shelf break of Korea. Total organic carbon (%) ranged from 0.3% to 1.6% (average = 0.80%, n = 81), and the C/N ratio varied from 2.4 to 12.4 (average = 6.76, n = 81). The δ¹³C values ranged from ?25.86 to ?20.26‰ (average = ?21.47‰, n = 81), and δ¹⁵N values ranged from 4.37‰ to 8.57‰ (average = 6.72‰, n = 81). The contribution of the terrestrial fraction of organic matter to the total ranged from 4.4% to 97.7% (average = 24.4%, n = 81), suggesting higher amounts around the catchment area and lower amounts in the offshore area. The concentration of total n-alkanes (nC₂₅ ? nC₃₅) was higher at the boundary between the outer bay and inner shelf break (BOBIS). Average chain length and the carbon preference index both indicated that major leaf wax n-alkanes accounted for the observed distribution of terrestrial organic matter, and were dominant in the inner shelf break (around BOBIS) and outer shelf break. Based on the spatial distribution of the total n-alkanes and the sum of nC₂₇, nC₂₉, and nC₃₁, the terrestrial organic matter distribution was considered to be controlled by local oceanographic conditions, especially at the center of the BOBIS. In addition to enabling the distribution and source of terrestrial organic matter to be identified, the n-alkanes indicated that minor anthropogenic allochthonous organic materials were superimposed on the total organic materials in the central part of Yeosu Bay and the catchment area. The n-alkane indices revealed weathered petroleum contamination, with contamination levels being relatively low at the present time.     

Modeling the underwater light field fluctuations in coastal oceanic waters: Validation with experimental data

Modeling of the wave-induced underwater light fluctuations at near-surface depths in coastal oceanic waters is challenging because of the surface roughness and strong anisotropic effects of the light field. In the present work, a simple and computationally efficient radiative transfer model is used for the wind-driven sea surface for simulating underwater light fields such as downwelling irradiance (E_d), upwelling irradiance (E_u), and upwelling radiance (L_u) in a spatial domain. It is an extension of our previous work that essentially combines the air–sea interface of the wind-driven sea surface with transmittance and reflectance along with the diffuse and direct components of the homogenous and inhomogeneous water column. The present model simulates underwater light fields for any possible values of absorption and backscattering coefficients. To assess the performance of the model, the E_d, E_u, and L_u profiles predicted by the model are compared with experimental data from relatively clear and turbid coastal waters. Statistical results show significantly low mean relative differences regardless of the wavelength. Comparison of the simulated and in-situ time series data measured over rough sea surfaces demonstrates that model-observation agreement is good for the present model. The Hydrolight model when implemented with the modified bottom reflectance and phase function provides significantly better results than the original Hydrolight model without consideration of the bottom slope and vertically varying phase function. However, these results are non-spatial and have errors fluctuating at different wavelengths. To further demonstrate the efficiency of the present model, spatial distribution patterns of the underwater light fields are simulated based on the measured data from a coastal station for different solar zenith angles (under sunny condition). Simulated wave-induced fluctuations of the underwater lights fields show a good consistency with in-situ data for a few near-surface depths. The present model also provides a reasonable approximation for simulating wave-induced effects on the downward irradiance field and its anisotropic conditions caused by the surface roughness, wavelength and angle of incidence.     

A new formula for saturated water steam pressure within the temperature range −25 to 220°C

Instead of approximation formula ln(E(t)/E(0)) = [(a ? bt)t/(c + T)] commonly used at present for representing dependence of pressure of saturated streams of liquid water E upon temperature we suggested new approximation formula of greater accuracy in the form ln(E(t)/E(0)) = [(A ? Bt + Ct ²)t/T], where t and T are temperature in °C and K respectively. For this formula with parameters A = 19.846, B = 8.97 × 10^?3, C = 1.248 × 10^?5 and E(0) = 6.1121 GPa with ITS-90 temperature scale and for temperature range from 0°C to 110°C relative difference of approximation applying six parameter formula by W. Wagner and A. Pruß 2002, developed for positive temperatures, is less than 0.005%, that is approximately 15 times less than accuracy obtained with the firs formula. Increase of temperature range results in relative difference increasing, but for even temperature range from 0°C to 220°C it does not higher than 0.1%. For negative temperatures relative difference between our formula and a formula of D. M. Murphy and T. Koop, 2005, is less than 0.1% for temperatures higher than ?25°C. This paper also presents values of coefficients for approximation of Goff and Grach formula recommended by IMO. The procedure of finding dew point T _d for known water steam pressure e _n based on our formula adds up to solving an algebraic equation of a third degree, which coefficients are presented in this paper. For simplifying this procedure this paper also includes approximation ratio applying a coefficient A noted above, in the form T _d (e _n ) = \(\frac{{AT_0 }}{{A - \varepsilon }}\) + 0.0866?² + 0.0116?^10/3, where ? = ln(e _n /E(T ₀)). Error of dew point recovery in this ratio is less than 0.005 K within the range from 0 to 50°C.     

引入拖曳系数参数化的海冰自由漂流模拟研究

Many interesting characteristics of sea ice drift depend on the atmospheric drag coefficient(C_a) and oceanic drag coefficient(C_w).Parameterizations of drag coefficients rather than constant values provide us a way to look insight into the dependence of these characteristics on sea ice conditions.In the present study,the parameterized ice drag coefficients are included into a free-drift sea ice dynamic model,and the wind factor α and the deflection angle θ between sea ice drift and wind velocity as well as the ratio of C_a to C_w are studied to investigate their dependence on the impact factors such as local drag coefficients,floe and ridge geometry.The results reveal that in an idealized steady ocean,C_a/C_w increases obviously with the increasing ice concentration for small ice floes in the marginal ice zone,while it remains at a steady level(0.2-0.25) for large floes in the central ice zone.The wind factor α increases rapidly at first and approaches a steady level of 0.018 when A is greater than 20%.And the deflection angle θ drops rapidly from an initial value of approximate 80° and decreases slowly as A is greater than20%without a steady level like α.The values of these parameters agree well with the previously reported observations in Arctic.The ridging intensity is an important parameter to determine the dominant contribution of the ratio of skin friction drag coefficient(C_s' /C_s) and the ratio of ridge form drag coefficient(C_r'/C_r) to the value of C_a/C_w,α,and θ,because of the dominance of ridge form drag for large ridging intensity and skin friction for small ridging intensity among the total drag forces.Parameterization of sea ice drag coefficients has the potential to be embedded into ice dynamic models to better account for the variability of sea ice in the transient Arctic Ocean.     

东印度洋5种缘毛类纤毛虫(钟虫属和聚缩虫)水平分布初次报道

腹壁纤毛虫是一种附着在浮游动物上的原生生物,尤其是附着在桡足类和甲壳类上的。而缘毛虫是可以以自由或寄生的形式在世界各沿海地区和港湾处被发现。本研究首次对东印度洋表层至200 m深海域的缘毛类纤毛虫以及其水平分布展开了研究。根据纤毛虫的形态、纤毛结构和茎的形态等的特征,在2014年4月10日至5月13日东印度洋航次的浮游生物拖网样品中鉴定出了五种富腹纤毛虫,海洋钟形虫Vorticella oceanica、交替聚缩虫Zoothamnium alternans、阿拉聚缩虫Zoothamnium alrasheidi、远洋聚缩虫Zoothamnium pelagicum和海洋聚缩虫Zoothamnium marinum。并通过光显微镜和扫描显微镜拍摄的照片,说明了其形态、尺寸和特征。研究结果表明,海洋钟形虫和远洋聚缩虫的分布与硅藻（如,密聚角毛藻Chaetoceros coarctatus）和桡足类（如,短角长腹剑水蚤Oithona brevicornis）等寄主有关,也包括甲藻（如,三角角藻Ceraitum tripose）周围的一些个体。这些附着纤毛虫的分布在东印度洋海域东南区以海洋钟形虫、远洋聚缩虫和海洋聚缩虫为主,而在孟加拉湾北部则有大量的阿拉聚缩虫。这种分布的变化可能是与寄主的分布有关,如桡足类（短角长腹剑水蚤）和硅藻（密聚角毛藻）的分布影响。     

Ultimate Lateral Capacity of Rigid Pile in <Emphasis Type="Italic">c</Emphasis>–<Emphasis Type="Italic">φ</Emphasis> Soil

To date no analytical solution of the pile ultimate lateral capacity for the general c–φ soil has been obtained. In the present study, a new dimensionless embedded ratio was proposed and the analytical solutions of ultimate lateral capacity and rotation center of rigid pile in c–φ soils were obtained. The results showed that both the dimensionless ultimate lateral capacity and dimensionless rotation center were the univariate functions of the embedded ratio. Also, the ultimate lateral capacity in the c–φ soil was the combination of the ultimate lateral capacity (f _c ) in the clay, and the ultimate lateral capacity (f _φ ) in the sand. Therefore, the Broms chart for clay, solution for clay (φ=0) put forward by Poulos and Davis, solution for sand (c=0) obtained by Petrasovits and Awad, and Kondner’s ultimate bending moment were all proven to be the special cases of the general solution in the present study. A comparison of the field and laboratory tests in 93 cases showed that the average ratios of the theoretical values to the experimental value ranged from 0.85 to 1.15. Also, the theoretical values displayed a good agreement with the test values.     

Retrieval of total ozone in the mesosphere with a new model of electronic-vibrational kinetics of O<Subscript>3</Subscript> and O<Subscript>2</Subscript> photolysis products

The paper presents a new model of electronic-vibrational kinetics of the products of ozone and molecular oxygen photodissociation in the terrestrial middle atmosphere. The model includes 45 excited states of the oxygen molecules O₂(b ¹, Σ _g ⁺ ,v= 0−2), O₂ (a ¹Δ _g , v= 0−5), and O₂(X ³Σ _g ⁻ , v= 1−35) and of the metastable atom O (¹ D) and over 100 aeronomic reactions. The model takes into account the dependence of quantum yields of the production of O₂(a ¹Δ _g , v= 0−5) in a singlet channel of ozone photolysis in the Hartley band on the wavelength of photolytic emission. Taking account of the electronic-vibrational kinetics is important in retrieval of the vertical profiles of ozone concentration from measured intensities of the Atm and IR Atm emissions of the oxygen bands above 65 km and leads to an increase in the ozone concentration retrieved from the 1.27-μm emission, in contrast to the previous model of pure electronic kinetics. Sensitivity analysis of the new model is made for variations in the concentrations of atmospheric constituents ([O₂], [N₂], [O(³P)], [O₃], [CO₂]), the gas temperature, rate constants of the reactions, and quantum yields of the reaction products. A group of reactions that most strongly affect the uncertainty of ozone retrieval from measured intensities of atmospheric emissions of molecular oxygen O₂(b ¹Σ _g ⁺ , v) and O₂(a ¹Δ _g , v) has been determined. Original Russian Text ? V.A. Yankovsky, V.A. Kuleshov, R.O. Manuilova, A.O. Semenov, 2007, published in Izvestiya AN. Fizika Atmosfery i Okeana, 2007, Vol. 43, No. 4, pp. 557–569.     

Experimental Study on Crescent Waves Diffracted by A Circular Cylinder

Crescent waves often observed on the sea surface are unusual wave pattern induced by the instability of Stokes wave. The paper presents the experimental results of the wave field around a circular cylinder generated by the diffraction of crescent wave in order to examine the difference of diffracted crescent waves from the commonly-used diffracted Stokes waves. The results show that with the existence of the cylinder, the crescent wave pattern can still get fully developed, and with the presence of this type of wave pattern, the symmetry breaking of the wave amplitude distribution occurs and there are extra wave components at the frequencies of 0.5ω₀, 1.5ω₀ and 2.5ω₀ (ω₀ is the frequency of Stokes waves) appearing in the wave amplitude spectrum.     

On the spatial–temporal variations in the chlorophyll-<Emphasis Type="Italic">a</Emphasis> concentration on the Peter the Great Bay shelf during the winter–spring phytoplankton bloom according to satellite and subsatellite data

Chlorophyll-a concentration (C _chl) variations in the cross section within and outside the Peter the Great Bay shelf during different stages of the winter–spring phytoplankton bloom in 2003–2005 has been considered based on a ship (obtained during the R/V Akademik M.A. Lavrent’ev voyage of February 26 to March 9, 2003) and MODIS-Aqua spectroradiometer and the SeaWiFS color-scanner satellite data. A comparison of the C _chl variability obtained from the ship and satellite data indicates that these data are inconsistent. According to satellite data obtained at the MUMM atmospheric correction, the C _chl variability is distorted less than the NIR-correction data. Studying the variations in the coefficients of light absorption by the detritus and yellow substance (a _dg) and light backscattering by suspended particles (b _bp), C _chl, chlorophyll-a fluorescence (F _chl) according to the satellite data allow us to state that the variations in the discrepancy between the satellite and ship C _chl values are mainly caused by the variations in the content of the detritus and yellow substance in water. Based on the satellite data, it has been revealed that the a _dg values increase with increasing wind mixing after the phytoplankton bloom (about 2–5 km areas where the a _dg, C _chl, F _chl, and bbp values abruptly increased in 2005, apparently due to eddy formation). It has been indicated that the F _chl characteristic, which is close to C _chl, increases when the favorable conditions for the phytoplankton bloom deteriorate. Therefore, this characteristic cannot be used to identify C _chl under the indicated conditions.     

Intrusive layering of the Antarctic slope front

Cascading of cold Antarctic shelf water (ASW) initiates compensatory isopycnic upwelling of the warm Circumpolar Deep Water (CDW). The baroclinic/thermoclinic Antarctic slope front (ASF) is formed, and a mesoscale intrusive structure develops on the shelf edge and slope. Mesoscale processes when the ASF peaks are periodically accompanied by local baroclinic instability, which forms a smaller-scale intrusive structure. Therefore, the ASF is naturally subdivided into two layers according to the intrusion scales (vertical δН and horizontal L) and the horizontal parameters of the front (thermoclinity (T_L)_ρ and baroclinity γ_ρ). Analysis of ASF intrusive layering due to the baroclinic factor supports the following conclusion: the higher the (T_L)_ρ of the ASF, the greater the intrusion intensity |δθ| (temperature anomaly amplitude), while an increase in γ_ρ of the ASF leads to a decrease in intrusion scales δН and L. Frontal intrusions can be distinguished by a development degree. Regardless of the degree of development, all warm intrusions are characterized by vertical density stratification, while cold intrusions are characterized by density quasihomogeneity. According to field data, the ASF instability process is subdivided into four stages. When theASF is baroclinically unstable, the local baroclinic deformation radius Rd_L of the front is close in magnitude to the horizontal scale L of the intrusions that form, and their characteristic vertical scale δH is close to the typical vertical scale of front instability.     

Determining the influence of wind-wave breaking on the dissipation of the turbulent kinetic energy in the upper ocean and on the dependence of the turbulent kinetic energy on the stage of wind-wave development

New experimental data that make it possible to explain and predict the observed variability of turbulent-energy dissipation in the upper ocean are discussed. For this purpose, the dependence of the energy dissipation rate of breaking wind waves on their propagation velocity (see [1]) is used. The turbulent-energy dissipation values obtained earlier in [2, 3] by a direct method are compared to the results of radar measurements of individual breaking events presented in [1]. On the basis of this comparison, a strong dependence of the turbulent-energy dissipation value on the stage of wind-wave development, which is characterized by the ratio U _a /c _p (U _a is the wind speed and c _p is the phase speed of the peak of the wind-wave spectrum) is confirmed. This dependence was found earlier purely empirically. Moreover, it is shown that the theoretically obtained dependence (c _p /U _a )⁴, does not contradict the available empirical data. The results of this study opens possibilities for scientifically substantiated calculations of greenhouse-gas exchange (specifically, CO₂ exchange between the ocean and the atmosphere).     

水下溢油油滴粒径分布实验研究

Oil droplet size distribution(ODSD) plays a critical role in the rising velocity and transport of oil droplets in subsurface oil releases. In this paper, subsurface oil release experiments were conducted to study ODSD under different experimental conditions in a laboratory water tank observed by two high-speed cameras in March and April 2017. The correlation formulas Oh=10.2 Re~(–1) and Oh=39.2 Re~(–1)(Re represents Reynolds number and Oh represents Ohnesorge number) were established to distinguish the boundaries of the three instability regimes in dimensionless space based on the experimental results. The oil droplet sizes from the experimental data showed an excellent match to the Rosin–Rammler distribution function with determination coefficients ranging from 0.86 to 1.00 for Lvda 10-1 oil. This paper also explored the influence factors on and change rules of oil droplet size. The volume median diameter d50 decreased steadily with increasing jet velocity, and a sharp decrease occurred in the laminar-breakup regime. At Weber numbers(We) 100, the orifice diameter and oil viscosity appeared to have a large influence on the mean droplet diameter. At 100We1 000, the oil viscosity appeared to have a larger influence on the relative mean droplet diameter.     

Vertical distribution of suspended particulate matter in the Caspian Sea in early summer

The features of the vertical distribution of chlorophyll a, particulate organic carbon and its isotopic composition, total suspended particulate matter (SPM), and the structure of the phytoplankton community in the Middle and South Caspian Sea in May–June 2012 are discussed. The subsurface chlorophyll a maximum (SCM) was found everywhere at depths of ~20 to 40–60 m. The position of this layer is confined to the depth of the seasonal thermocline, which is determined by the development of a cold-water (dark) phytocenosis. The genesis of this layer was studied. The increase in chlorophyll a concentration in this layer is caused by an abundance of phytoplankton or an increased concentration of this phytopigments per algal cell. The highest values of the studied organic compounds and phytoplankton biomass are revealed as close to the seasonal thermocline extending from the southern periphery of the Derbent Depression to the Apsheron Sill, which is determined by the bottom topography. The presence of chlorophyll a at depths exceeding 300 m (up to ≥1 mg/m³) was revealed. This was supported by findings of individual algal cells containing chlorophyll a and even their accumulations in the deep water layer. The most probable mechanisms responsible for the presence of these cells at the deep water level are discussed in the paper. The vertical distribution of the values of the organic carbon isotopic composition is primarily controlled by the vertical structure of phytoplankton and chlorophyll a in the water column up to ~500 m and by biogeochemical processes at the redox barrier (~600 m layer). The relative stability of chlorophyll a and the stability of pheophytin a in anaerobic environments were verified. A significant amount of weakly transformed chlorophyll a was found close the sea bottom.