Distributions and seasonal variations of dissolved carbohydrates in the Jiaozhou Bay,China

Surface seawater samples were collected in the Jiaozhou Bay, a typical semi-closed basin located at the western part of the Shandong Peninsula, China, during four cruises. Concentrations of monosaccharides (MCHO), polysaccharides (PCHO) and total dissolved carbohydrates (TCHO) were measured with the 2,4,6-tripyridyl-s-triazine spectroscopic method. Concentrations of TCHO varied from 10.8 to 276.1 μM C for all samples and the ratios of TCHO to dissolved organic carbon (DOC) ranged from 1.1 to 67.9% with an average of 10.1%. This result indicated that dissolved carbohydrates were an important constituent of DOC in the surface seawater of the Jiaozhou Bay. In all samples, the concentrations of MCHO ranged from 2.9 to 65.9 μM C, comprising 46.1 ± 16.6% of TCHO on average, while PCHO ranged from 0.3 to 210.2 μM C, comprising 53.9 ± 16.6% of TCHO on average. As a major part of dissolved carbohydrates, the concentrations of PCHO were higher than those of MCHO. MCHO and PCHO accumulated in January and July, with minimum average concentration in April. The seasonal variation in the ratios of TCHO to DOC was related to water temperature, with high values in January and low values in July and October. The concentrations of dissolved carbohydrates displayed a decreasing trend from the coastal to the central areas. Negative correlations between concentrations of TCHO and salinity in July suggested that riverine input around the Jiaozhou Bay had an important effect on the concentrations of dissolved carbohydrates in surface seawater. The pattern of distributions of MCHO and PCHO reported in this study added to the global picture of dissolved carbohydrates distribution.     

A new species of the glass sponge genus Walteria (Hexactinell-ida: Lyssacinosida: Euplectellidae) from northwestern Pacific seamounts,providing a biogenic microhabitat in the deep sea

We report on a hexactinellid sponge new to science, Walteria demeterae sp. nov., which was collected from the northwestern Pacific seamounts at depths of 1 271–1 703 m. Its tubular and basiphytous body, extensive lateral processes, numerous oval lateral oscula which are irregularly situated in the body wall, the presence of microscleres with oxyoidal, discoidal and onychoidal outer ends, and the absence of anchorate discohexasters,indicate it belongs to the genus Walteria of family Euplectellida...     

Comparison of vane shear and fall cone strengths of soft marine clay

A total of 1,014 measures of sediment shear strengths were measured by means of miniature vane shear and fall cone tests on five gravity cores collected in Eckernfo‐erde Bay, Baltic Sea. Paired t test was used to compare the shear strengths measured by the two methods. It was found that fall cone strength calculated with Wood's K₆₀value (0.29) overestimates the vane shear strength by 0.15 kPa (a = 0.001) and the sample mean of the fall cone strength is 4.1% higher than the mean of the vane shear strength. However, fall cone strength calculated with Hansbo's K₆₀ value (0.24) underestimates the vane shear strength by 0.88 kPa (a = 0.001), and the sample mean of the fall cone strength is 13.8% less than the mean of the vane shear strength. Both calculated fall cone strengths are significantly different from the vane shear strength, with a p value of less than 0.001. Regression analysis of the Echernfoerde Bay data indicates that a new K₆₀ value is 0.275 with a confidence interval (a = 0.01) from 0.2704 to 0.2786. Paired t test shows that there is no significant difference between miniature vane shear and fall cone tests for these samples if the fall cone strength is calculated with K₆₀ = 0.275.     

牙鲆幼鱼越冬饲养期环境因子研究

本文重点研究牙鲆鱼越冬饲养期间所需的适宜温度和盐度条件,以及牙鲆对酸碱度的耐受力。研究结果表明温度是影响牙鲆在越冬期标准代谢的主要环境因子。７～１４．５℃是越冬期牙鲆能量代谢变动最低的温度区间,也是最适宜的温度范围。盐度也是影响牙鲆越冬期的环境因子,在７～１４．５℃的温度条件下,其盐度阈值下限为２０;４０仍属适宜盐度。牙鲆的耐酸力比耐碱性强,９６ｈ和４８ｈ致死的ｐＨ值分别为４．４５和４．２０,当ｐＨ值为９．３０时,牙鲆１６ｈ死亡。     

伪近邻方法在ARMA系统阶数判别中的应用

从相空间重构的角度,提出利用伪近邻方法判别ＡＲＭＡ 系统的总阶数。该方法可在数据量较小和阈值固定的情况下判别ＡＲＭＡ 系统总阶数。数值计算表明,使用该方法判别线性ＡＲＭＡ系统总阶数,取得了比较满意的结果。     

Pristine or altered: low-Mg calcite shells survived from massive dolomitization? A case study from Miocene carbonates

Low-Mg calcite shells have been widely used to reconstruct the chemistry of ancient seawater. There is always a question: are the shells chemically pristine? This paper presents the isotope and elemental geochemistry of low-Mg calcite bivalve shells in late Miocene platform carbonates, SE Spain. The platform carbonates were extensively dolomitized, and limestone is restricted to older stratal units, and to units mainly in topographically higher and more landward strata. Low-Mg calcite oyster shells were completely dissolved out in the basinward dolomite, but are well preserved in the limestone. These shells appear to retain the original growth microstructures, based on hand samples. Under the microscope, however, dissolution and recrystallization, as well as pristine growth lines are all present. Sr isotopes in these shells range from that of normal Miocene seawater to radiogenic values. δ¹⁸O and δ¹³C values, and Mg, Sr, and Na concentrations in these shells are rather variable. The high end members are consistent with the typical values of modern/late Miocene normal-seawater low-Mg calcite shells, whereas the low end members are close to those of diagenetic calcite cements, which have low δ¹⁸O, δ¹³C, Sr and Na values, and radiogenic Sr. The Nijar shells were altered physically and chemically to different degrees by diagenesis, although these shells are consistent with some “criteria” of unalteration. The isotopic and trace-element data collected in altered and pristine (or less altered) portions coexisting in the same shells are clearly differentiable. Quantitative simulation of covariations of geochemical pairs indicates that solid mixing of unaltered and altered portions by sampling is consistent with the variations in isotopic and elemental data recorded in the Nijar shells. The geological significance of this study is that ancient fabric-retentive calcite shells may have been altered geochemically although they may appear pristine. Calcite shells that underwent intensive diagenesis should be examined rigorously under the microscope, coupled with investigations of multiple geochemical proxies to assess chemical alteration. Only the data of unaltered shells can be used to reconstruct the chemistry of ancient seawater.     

退火对B掺杂纳米金刚石薄膜微结构和电化学性能的影响

采用热丝化学气相沉积法制备B掺杂纳米金刚石薄膜,并对薄膜进行真空退火处理,系统研究了不同退火温度对B掺杂纳米金刚石薄膜的微结构和电化学性能的影响.结果表明,当退火温度升高到800 ℃后,薄膜的Raman谱图中由未退火时在1157,1346,1470,1555 cm^-1处的4个峰转变为只有D峰和G峰,说明晶界上的氢大量解吸附量减少;并且D峰和G峰的积分强度比I_D/I_G值变为最小,即sp²相团簇     

Influence of core property on multi-electron process in slow collisions of isocharged sequence ions with neon

Influence of core property on multi-electron process in the collisions of q=6-9 and 11 isocharged sequence ions with Ne is investigated in the keV/u region. The cross-section ratios of double-, triple-, quadruple- and total multi-electron processes to the single electron capture process as well as the partial ratios of different reaction channels to the relevant multi-electron process are measured by using position-sensitive and time-of-flight techniques. The experimental data are compared with the theoretical predictions including the extended classical over-barrier model, the molecular Columbic barrier model and the semi-empirical scaling law. Results show a core effect on multi-electron process of isocharge ions colliding with Neon, which is consistent with the results of Helium we obtained previously.     

九龙江口鳗苗溯河生态与资源研究

九龙江口Ｌｉ苗１９９４￣１９９６年溯河期为１９９４年１１月２０至１９９５年４月底。１９９５年１２月２０日至１９９６年５月底。鳗苗溯河期水温范围１１．５￣２２．５℃,盐度１．９８￣２５．００,透明度０．２￣１．１ｍ,九龙江口打石坑－嵩屿断面溯河鳗苗资源量１９９５年１９３ｋｇ,１９９６年２０８ｋｇ;海澄断面１９９５年３５ｋｇ,１９９６年５５ｋｇ。     

海洋沉积物孔隙水中阴阳离子含量的离子色谱法分析方法

分别采用Metrosep A Supp4-250型阴离子柱和Metrosep C 2-150型阳离子柱,以1.8 mmol/L Na2CO3 1.7 mmol/L NaHCO3和4 mmol/L酒石酸 0.75 mmol/L吡啶二羧酸为阴阳离子淋洗液,用离子色谱仪来测定海洋沉积物孔隙水中阴离子Cl-、Br-和SO42-浓度和阳离子Na 、NH4 、K 、Ca2 、Mg2 的浓度。特别是针对高Cl-和高Na 背景下Br-和NH4 的测定做了专门分析,得到了较理想的结果,建立了一套离子色谱法测定海洋沉积物孔隙水中常见的阴阳离子含量的实验方法。