Assessment of a Sr isotope vital effect (87Sr/86Sr) in marine taxa from Lee Stocking Island, Bahamas

Data from Lee Stocking Island, Bahamas, confirms the hypothesis that there are no vital effects with the uptake of Sr isotopes (⁸⁷Sr/⁸⁶Sr) at the present mass spectrometer resolution [±2×10^?5 (2σ)]. Our data set contains analyses of 40 samples derived from 37 different calcareous taxa inhabiting a wide range of carbonate subenvironments (i.e., reefal, intertidal, supratidal, mangrove). The mean value of our analyses was 0.709179 with a standard deviation of 2.4×10^?5 (2σ) which was very close to the long-term uncertainty of the strontium isotope methodology [±2.0×10^?5 (2σ)] and to the widely reported ⁸⁷Sr/⁸⁶Sr value of seawater, which clusters around 0.709175.     

冬季东寨港微微型浮游植物丰度、分布及影响因素

微微型浮游植物是水环境生态碳汇的重要基石之一,也是初级生产的重要执行者。选取了一个典型的陆海交界关键带环境——海南东寨港入海口水域,采集了东寨港红树林保护区开阔水域、入港河流和新埠海海端的微微型浮游植物的样品,通过流式细胞仪分析技术对样品进行分析,以探究它们在东寨港水域中的丰度、分布及环境指示意义。结果表明,冬季水域微微型浮游植物以真核浮游植物(Eukaryote,Euk)和聚球藻(Synechococcus,Syn)两大类群为主,其中聚球藻有两个亚群,分别为富含藻蓝蛋白聚球藻(Phycocyanin-rich,PC)和富含藻红蛋白聚球藻(Phycoerythrin-rich,PE)。Syn-PC、Syn-PE和Euk在东寨港水域表层水体的平均丰度分别为(2.61×10⁴±1.09×10⁴)、(3.06×10⁴±7.05×10³)、(1.56×10⁵±8.03×10⁴) cells/m L,底层水体的平均丰度分别为(2.64×10⁴±...     

Circulation of Intermediate and Deep Waters in the Philippine Sea

The circulation of intermediate and deep waters in the Philippine Sea west of the Izu-Ogasawara-Mariana-Yap Ridge is estimated with use of an inverse model applied to the World Ocean Circulation Experiment (WOCE) Hydrographic Program data set. Above 1500 m depth, the subtropical gyre is dominant, but the circulation is split in small cells below the thermocline, causing multiple zonal inflows of intermediate waters toward the western boundary. The inflows along 20°N and 26°N carry the North Pacific Intermediate Water (NPIW) of 11 × 10⁹ kg s⁻¹ in total, at the density range of 26.5σ_θ–36.7σ₂ (approximately 500–1500 m depths), 8 × 10⁹ kg s⁻¹ of the NPIW circulate within the subtropical gyre, whereas the rest is conveyed to the tropics and the South China Sea. The inflow south of 15°N carries the Tropical Salinity Minimum water of 35 × 10⁹ kg s⁻¹, nearly half of which return to the east through a narrow undercurrent at 15–17°N, and the rest is transported into the lower part of the North Equatorial Countercurrent. Below 1500 m depth, the deep circulation regime is anti-cyclonic. At the density range of 36.7σ₂, – 45.845σ₄ (approximately 1500–3500 m depths), deep waters of 17 × 10⁹ kg s⁻¹ flow northward, and three quarters of them return to the east at 16–24°N. The remainder flows further north of 24°N, then turns eastward out of the Philippine Sea, together with a small amount of subarctic-origin North Pacific Deep Water (NPDW) which enters the Philippine Sea through the gap between the Izu Ridge and Ogasawara Ridge. The full-depth structure and transportation of the Kuroshio in total and net are also examined. It is suggested that low potential vorticity of the Subtropical Mode Water is useful for distinguishing the net Kuroshio flow from recirculation flows. This revised version was published online in August 2006 with corrections to the Cover Date.     

南极罗斯海重力场特征及莫霍面深度反演

本文基于中国南极考察第30航次、第32航次所获得的实测重力资料,结合NGDC资料,开展12个航次重力场数据的平差融合工作,全部386个交点平差后标准差减小为±1.53×10−5 m/s2,与卫星重力差值平均值为1.49×10−5 m/s2,均方差为±3.81×10−5 m/s2,并在此基础上采用频率域界面反演法计算莫霍面深度。研究发现,与沉积盆地对应重力异常低值相悖,在罗斯海北部盆地、维多利亚地盆地、中央海槽、东部盆地4个主要盆地腹地却表现为重力异常高值,跨度达100 km以上。莫霍面深度分布整体呈南深北浅之势,范围为10~28 km。伴随着罗斯海西部盆地的多次拉张及岩浆活动,该区域的地壳厚度和莫霍面深度高值和低值相间分布,并表现出越来越大的差异性。综合剖面结果表明,罗斯海重力异常值的长波长变化与莫霍面的起伏呈正相关关系,但是反演的莫霍面深度与区域重力场特征并非完全对应,所以岩浆底侵和地壳侵入仍不足以导致罗斯海盆地的重力异常或盆地几何形状。     

2014年大西洋水在楚科奇边陲区域的上边界混合

This study presents an analysis of the CTD data and the turbulent microstructure data collected in 2014, the turbulent mixing environment above the Atlantic Water(AW) around the Chukchi Borderland region is studied.Surface wind becomes more efficient in driving the upper ocean movement along with the rapid decline of sea ice,thus results in a more restless interior of the Arctic Ocean. The turbulent dissipation rate is in the range of4.60×10~(–10)~(–3.31×10~(–9) W/kg with a mean value of 1.33×10~(–9) W/kg, while the diapycnal diffusivity is in the range of1.45×10~(–6)–1.46×10~(–5)m~2/s with a mean value of 4.84×10~(–6) m~2/s in 200–300 m(above the AW). After investigating on the traditional factors(i.e., wind, topography and tides) that may contribute to the turbulent dissipation rate, the results show that the tidal kinetic energy plays a dominating role in the vertical mixing above the AW. Besides, the swing of the Beaufort Gyre(BG) has an impact on the vertical shear of the geostrophic current and may contribute to the regional difference of turbulent mixing. The parameterized method for the double-diffusive convection flux above the AW is validated by the direct turbulent microstructure results.     

Radar estimation of water content in cumulonimbus clouds

The method and results of radar researches of vertically and volumetric integrated water content in powerful cumulonimbus (Cb) clouds obtained for the first time are considered. It is established that in hailstorms of Northern Caucasus vertically integrated liquid (VIL) water content varies in limits from 8 up to 50 kg/m², in shower clouds—from 0.5 up to 12 kg/m², in Nimbostratus (Ns) clouds—it is usual less than 0.5 kg/m² and in clouds with a drizzle—less than 0.05 kg/m². The main water content of hailstorms in a stage of development is concentrated in their supercooled layer, in a maturity stage—in a layer from the ground up to height 8–10 km and in a stage of dissipation—in a ground layer. The ratio of VIL of the supercooled and warm parts of cloud allows estimating hail dangers of clouds and stage of their development. It is shown that the volume of hailstorms varies in limits from 10³ up to 5 × 10⁴ km³ and their volumetric integrated mass (VIM) of water content — from 10⁵ up to 6 × 10⁶ tons. The volume of hail localization seldom exceeds 5–25% from total cloud volume, but its contribution to VIM achieves 30–60%. Speed of precipitation formation in powerful hailstorms achieves 1 × 10⁴−5 × 10⁵ tons/min and the same order of value has speed of recession of VIM in their stage of dissipation.     

Helium and oxygen isotope analyses of hydrothermal fluids from the East Pacific Rise between 17°S and 19°S

 Hydrothermal vent fields south of the Garret Fracture zone were sampled for the isotope composition of helium and oxygen ([¹⁸O]H₂O/[¹⁶OH₂O). The helium isotopes end-member (³He / ⁴He=8.3×R _a and [⁴He]≈1.2–2.4×10^-5 cm³ STP g^-1) is quite similar to other known hydrothermal sites pointing to the homogeneous helium composition of the upper mantle. The δ¹⁸O end-member value (δ¹⁸O≈0.5–0.6‰) confirms previous suggestions from other sites and from isotope modeling, that hydrothermal fluids are slightly enriched in ¹⁸O relative to the ocean as a result of water–rock interactions at high temperature. Received: 11 December 1995/Revision received: 20 December 1996     

南半球亚极地流涡的平均特征及其变化

Based on the Simple Ocean Data Assimilation(SODA) products,we study the mean properties and variations of the Southern Hemisphere subpolar gyres(SHSGs) in this paper.The results show that the gyre strengths in the SODA estimates are(55.9±9.8)×10~6m~3/s for the Weddell Gyre(WG),(37.0±6.4) ×10~6m~3/s for the Ross Gyre(RG),and(27.5±8.2)×10~6m~3/s for the Australian-Antarctic Gyre(AG),respectively.There exists distinct connectivity between the adjacent gyres and then forms an oceanic super gyre structure in the southern subpolar oceans.And the interior exchanges are about(8.0±3.2)×10~6m~3/s at around 70°E and(4.3±3.1)×10~6m~3/s at around 140°E.The most pronounced variation for all three SHSGs occurs on the seasonal time scale,with generally stronger(weaker)SHSGs during austral winter(summer).And the seasonal changes of the gyre structures show that the eastern boundary of the WG and AG extends considerably further east during winter and the interior exchange in the super gyre structure increases accordingly.The WG and RG also show significant semi-annual changes.The correlation analyses confirm that the variations of the gyre strengths are strongly correlated with the changes in the local wind forcing on the semi-annual and seasonal time scales.     

The uranium content and the activity ratio234U/238U in marine organisms and sea water in the western North Pacific

The uranium content and activity ratio A²³⁴U/A²³⁸U were determined in open ocean water, marine plankton, marine algae and sea water in the environment in which plankton and algae live. The average uranium content of 3.34±0.28×10⁻⁶ g/l and the average activity ratio of 1.13±0.04 were obtained in open ocean water. The uranium contents in plankton and algae were respectively from 1.7 to 7.8×10⁻⁷ g/g and 0.4 to 23.5×10⁻⁷ g/g on dry basis with the respective concentration factors of 48 to 260 and 10 to 733. The activity ratio in plankton and algae ranged from 1.07 to 1.18 which coincided well with those in the environmental sea water.     

黄河口及渤海湾海水的密度

用磁力浮沉子法溶液密度测量装置,在15—25℃之间的三个温度下测定了黄河口渤海湾36个站位海水样品(于1989年7月和1990年7月采集)的密度,发现所有实验测定值与根据其盐度和温度由1980年国际海水状态方程的计算值比较,均有明显的正偏差,此正偏差随海水盐度降低而增大。在黄河口渤海湾海水样品全部盐度范围内,已发现其海水密度正偏差与海水[Ca~(2+)]/s,[Mg~(2+)]/s,[SO_4~(2-)]/s之间呈指数曲线相关,而与碱度之间呈S形曲线相关,但在盐度25.72—31.57范围内都可近似看作直线相关。黄河口渤海湾海水的高碱度、高[Ca~(2+)]/s为其特征,这也是其密度正偏差的主要影响因素。本文还给出了计算黄河口及渤海湾海水密度的公式。     

Phytoplankton of the Large Aral Sea in June 2008

The species composition, cell concentration, and biomass in the surface layer were determined at 10 stations in the central part of the Western Basin (WB) and one station in the Eastern Basin (EB) of the Large Aral Sea. A total of 42 algae species were found. Diatoms had the highest number of species. The similarity of the phytoplankton composition in the WB was high, whereas the phytoplankton composition in the WB and EB differed significantly. In the WB, the cell concentration and biomass of the phytoplankton varied from 826 × 10³ to 6312 × 10³ cells/l (the mean value was 1877 × 1586 × 10³ cells/l) and from 53 to 241 μgC/l (the mean value was 95 × 56 μgC/l). In the EB, the phytoplankton abundance was 915 × 10³ cells/l and 93 μgC/l. The vertical distribution of the phytoplankton in upper 35 m was investigated at one station in the WB. The maximum values of the algal cell concentration and biomass were recorded under the thermocline at the 20 m depth. The integrated biomass of the phytoplankton was 14 gC/m².     

Numerical experiment for strontium-90 and cesium-137 in the Japan Sea

A numerical experiment is carried out to reproduce distribution of concentration of ⁹⁰Sr and ¹³⁷Cs, estimate their total amount and verify their source in the Japan Sea. Model results are in good agreement with observational findings in the Japan Sea expeditions between 1997 and 2002 by the Japan Atomic Energy Agency. Vertical profiles of the concentration of ⁹⁰Sr and ¹³⁷Cs show exponential decreases with depth from the sea surface to the sea bottom. From the model and observational results, it is suggested that the concentration of ⁹⁰Sr and ¹³⁷Cs in the surface layer is approximately in the range of 1.0–1.5 Bq/m³ and 2.0–2.5 Bq/m3, respectively. On the other hand, it is found that the concentration in the intermediate and deep layer is higher than that observed in the northwestern Pacific Ocean, suggesting active winter convection in the Japan Sea. The total amount of ⁹⁰Sr and ¹³⁷Cs in the seawater is evaluated to be 1.34 × 10¹⁵ Bq and 2.02 × 10¹⁵ Bq, respectively, in the numerical experiment, which demonstrates an estimation by observational data obtained in the Japan Sea expeditions. The total amount of ⁹⁰Sr and ¹³⁷Cs changed during the second half of 20th century corresponding to deposition at the sea surface with the maximums of 4.86 × 10¹⁵ Bq for ⁹⁰Sr and 7.33 × 10¹⁵ Bq for ¹³⁷Cs, respectively, in the mid-1960s. The numerical experiment suggests that the main source of ⁹⁰Sr and ¹³⁷Cs has been global fallout, although there have been some potential sources in the Japan Sea.     

Validating NO<Subscript>2</Subscript> measurements in the vertical atmospheric column with the OMI instrument aboard the EOS Aura satellite against ground-based measurements at the Zvenigorod Scientific Station

Data on the NO₂ content in the vertical column of the atmosphere obtained with the Ozone Monitoring Instrument (OMI) aboard the EOS Aura satellite (United States) in the period from October 2004 to October 2007 are compared with the results of ground-based measurements at the Zvenigorod Scientific Station (55.7° N, 36.8° E). The “unpolluted”; part of the total NO₂ content in the atmospheric column, which mostly represents the stratosphere, and the NO₂ contents in the vertical column of the troposphere, including the lower layer, which is subject to pollution, are included in the comparison. The correlation coefficient between the results of ground-based and satellite measurements of the “unpolluted” total NO₂ content is ∼0.9. The content values measured with the OMI instrument are smaller than the results of ground-based measurements (on average, by (0.30 ± 0.03) × 10¹⁵ cm⁻² or by (11 ± 1)%). Therms discrepancy between the satellite and ground-based data is 0.6 × 10¹⁵ cm⁻². The NO₂ content in the vertical column of the troposphere from the results of satellite measurements is, on average, (1.4 ± 0.5) × 10¹⁵ cm⁻², (or about 35%) smaller than from the results of ground-based measurements, and the rms discrepancy between them is about 200%. The correlation coefficient between these data is ∼0.4. This considerable discrepancy is evidently caused by the strong spatial (horizontal) inhomogeneity and the temporal variability of the NO₂ field during episodes of pollution, which leads to different (and often uncorrelated) estimates of the NO₂ content in the lower troposphere due to different spatial resolutions of ground-based and satellite measurements.     

Variability of the Kuroshio in the East China Sea in 1995

INTRODUCTIONTherearemanyresearchworksabbottheKUrOShioVTanditSSeaSOnalvacationintheEastChinaho(GUan,1988;Nishizawaetal.,1982;TangandTaShiro,1993;SunandKaneko,1993;Yuanetal.,1990;Yuanetal.,1993;Yuanetal.,1994;Yuanetal.,1995;LiuandYuan,1997a,b).~previou...     

Chemostratigraphic documentation of a complete Miocene intermediate-depth section in the Southern Ocean: Ocean Drilling Program Site 1120, Campbell Plateau off New Zealand

An integrated chemostratigraphic (⁸⁷Sr/⁸⁶Sr, δ¹³C and δ¹⁸O) study of benthic foraminifera is presented for a 210 m-thick, intermediate depth (upper/middle bathyal transition), Miocene nannofossil ooze section of Ocean Drilling Program Site 1120, Campbell Plateau off New Zealand. Our results indicate that new ⁸⁷Sr/⁸⁶Sr, δ¹³C and δ¹⁸O profiles are wholly consistent with their respective Miocene reference curves. These observations facilitate identification of a total of five reliable chemostratigraphic datums, which are based on the fundamental structural changes in the ⁸⁷Sr/⁸⁶Sr curve and paired simultaneous δ¹³C and δ¹⁸O events. The resultant age–depth relationship clearly shows that the Miocene (20–5 Ma) biopelagic sedimentation on the Campbell Plateau was essentially continuous at a moderate to high, linear sedimentation rate (17.5 m/m.y. with an exception of the uppermost 13 m). Our findings do not support the shipboard biostratigraphic age model, which assumes that the critical early–middle Miocene transition was interrupted by a major hiatus (<~3 m.y.). Because of its unique bathymetric setting at a paleowater-depth of ~ 600 m, which is among the shallowest of the coeval isotopically studied deep-sea sections in the South Pacific/Southern Ocean, Site 1120 will serve as a reference section for surveying the evolution of intermediate-water paleoceanography in the Southern Hemisphere across the middle Miocene climatic transition.     

ECOLOGICAL DISTRIBUTION OF HYDROCARBON-DEGRADATION BACTERIA IN XIAMEN HARBOR

The ecology of hydrocarbon-degrading bacteria were investigated during five cruises in Xiamen Harbor. The results demonstrated that number of hydrocarbon-degrading bacteria were 2.1×102-7.5×106 cell/1 and 1.7×102-1.5×106 ceil/g dry and hetcrotrophic bacteria were 3.0× 104-5.9× 109 cell/1 and 2.53× 103-5.0× 103 cell/g dry in seawater and sediment respectively. The isolated strains which can degrade the petroleum belong to fifteen genera. Most, strains can only degsade one kind of hydro- carbon or petroleum. The results showed that the population and the species-composition of hydro carbon-degrading microorganisms were positively correlated with existing level of oil pollution and with water temperature, but independent of total microbtat count.     

东马努斯海盆PACMANUS热液区Si-Fe-Mn-羟基氧化物的Sr、Nd、Pb同位素特征

Si-Fe-Mn-oxyhydroxides dredged at the PACMANUS(Papua New Guinea–Australia–Canada–Manus)hydrothermal field, Eastern Manus Basin, have 87Sr/86Sr=0.708 079–0.708 581; εNd=5.149 833–6.534 826;208Pb/204Pb=38.245–38.440; 207Pb/204Pb=15.503–15.560; 206Pb/204Pb=18.682–18.783. 87Sr/86 Sr isotope ratios are relatively homogeneous and close to the value of the surrounding seawater(0.709 16). The content of Sr in the samples contributed by seawater was estimated to be 76.7%–83.1% of total amount. The mixing temperature of hydrothermal fluids and seawater were ranging from 53.2°C to 72.2°C and the hydrothermal activities were unstable when the samples precipitated. The εNd values of all the samples are positive, which differ from the values of ferromanganese nodules(crusts) with hydrogenic origin. Nd was mainly derived from substrate rocks leached by hydrothermal circulation and preserved the hydrothermal signature. Pb isotopic compositions of most samples show minor variability except Sample #9–2 that has relatively high values of Pb isotopes. The Pb may be derived from the Eastern Manus Basin rocks leached by the hydrothermal fluid. The slightly lower 208Pb/204 Pb and207Pb/204 Pb values of the samples indicated that the hydrothermal circulation in PACMANUS was not entire and sufficient, or that hydrothermal circulation had transient changes in the past. Si-Fe-Mn-oxyhydroxides in the samples preserved the heterogeneities of local rocks.     

Volume and heat transports and material fluxes in the East China Sea during April 1994

INTRODUCTIONTherehavebeenmanystudiesandcomputationsonVToftheKuroshiointheEastChinaThisprojectwassupportedbytheNationalNaturalScienceFoundationofChinaundercontractNo.49476278.Asanditsvacation.Forexample,(1)basedonhydrographicobservationsatactionG(PN)f...     

A case study of near-inertial oscillation in the South China Sea using mooring observations and satellite altimeter data

A near-inertial oscillation (NIO) burst event in the west South China Sea (SCS) was observed by an upward-looking mooring Acoustic Doppler Current Profiler (ADCP) in summer 2004. The mooring station was located at 13.99°N, 110.52°E. The spectral analysis reveals that typhoon Chanchu is a major mechanism in triggering the NIO burst event. Before typhoon Chanchu passed over, the NIO signals were quite weak. The NIO band becomes the most energetic constituent of the circulation during the typhoon-wake period. The average peak power density (PD) reaches (5.3 ± 2.6) × 10² cm² s⁻² (cycles per hour, cph)⁻¹ with a maximum value of 9.0 × 10² cm² s⁻² cph⁻¹, i.e., 3.1 times higher than that of diurnal tide (DT), (1.7 ± 0.5) × 10² cm² s⁻² cph⁻¹. At the upper (80 m) and sub-upper (208 m) layers, the central frequency of the NIO band is 0.022 cph with a blueshift of about 9% above the inertial frequency f (0.02015 cph). At the lower layer (400 m), the central frequency of the NIO band is 0.021 cph with a blueshift of about 4% above the inertial frequency. The blueshifts are explained partially by the Doppler shift induced by the vorticity of mesoscale eddies. During the after-typhoon period, a resonance-like process between NIO and DT is observed in the upper layer. As the NIO frequency approaches the DT subharmonic frequency (0.5K₁), the PD of the NIO band rises sharply accompanied by a sharp drop of the PD of the DT band. The PD ratio of the two bands increases from 4.5 during the typhoon-wake period to 8 during the after-typhoon period, indicating the effect of the parametric subharmonic instability (PSI) mechanism.     

三门湾网采浮游植物季节变化及影响因素

于2015—2016年春(5月)、夏(8月)、秋(11月)和冬(1月)四个航次对三门湾18个站位进行拖网采集和理化因子测定,分析了三门湾浮游植物群落结构、优势种组成、时空分布和主要影响因素,并结合历史数据,分析了浮游植物群落结构的变化规律,探讨了其主要驱动因子。调查共检出浮游植物8门87属199种(含变种、变型和未定名种),其中硅藻51属149种,甲藻18属27种,绿藻、裸藻、隐藻、定鞭藻、金藻和蓝藻偶有检出。四季共检出优势种8属13种,其中琼氏圆筛藻(Coscinodiscus jonesianus)为全年优势种。浮游植物年均丰度为1632.04×10~4cell/m~3,其中春季最低(53.06×10~4cell/m~3),夏季最高(5548.91×10~4cell/m~3)。聚类和相似性分析结果表明,浮游植物群落季节变化和区域差异明显。典范对应分析表明,影响三门湾海域浮游植物群落的主要因子依次为温度、盐度、DIN和DSi。结合历史资料发现,三门湾浮游植物群落丰度总体呈增加趋势(排除20世纪80年代冬季赤潮影响),主要种类组成仍以硅、甲藻为主,赤潮藻及嗜氮性硅藻种类数及优势度均上升。此外,三门湾浮游植物由大型硅藻向链状硅藻演替。海域富营养化和水温上升可能是主要驱动因子。