The effect of membrane filtration on estimates of microbial ATP in New Zealand freshwaters

Concentrations of microbial ATP in 15 New Zealand lakes were determined using 2 extraction techniques. ATP was found in both the paniculate (>0.45 μm) and dissolved (<0.45 μm) fractions of the water samples. Higher concentrations of paniculate ATP were obtained when ATP was extracted directly from freshwater samples rather than following pre‐concentration on to membrane filters. Recovery of particulate ATP declined with increasing volumes of sample filtered. The magnitude of the filtration effect varied unpredictably between lakes and within lakes with time. Corrections for the presence of dissolved ATP were necessary before estimates of particulate ATP could be made by the direct extraction technique. Concentrations of dissolved ATP up to 1.2 μg L^‐1 were observed. The direct extraction technique is recommended for more accurate determination of particulate ATP in New Zealand freshwaters.     

突降盐度胁迫对大黄鱼(Pseudosciaena crocea)血清生理生化及鳃丝Na+/K+-ATP 酶活性的影响

采用海水盐度由25突降至21、17和13胁迫大黄鱼(Pseudosciaena crocea)的方法,研究了48h内血清生理生化和鳃丝Na+/K+-ATP酶活性的变化。结果表明,实验过程中三个盐度突降组的血清Na+、Ca2+离子浓度均未发生显著变化(P>0.05),血清K+浓度均显著升高(P<0.05),且升高幅度与盐度突降幅度呈正相关,最大值达14.03mmol/L(盐度13组,48h);血清Cl浓度在盐度21组未发生显著变化(P>0.05),17和13组则在48h时显著降低(P<0.05);三个盐度突降组的血清酶ALT、AST、LDH、CK-MB活性均显著高于对照组(P<0.05),随胁迫时间的延长呈先升后降的趋势,且变化幅度均与盐度突降幅度呈正相关;三个盐度突降组的鳃丝Na+/K+-ATP酶活力均呈先升后降的变化趋势,除盐度21组在12h时高于对照组外,活力均显著低于对照组(P<0.05),且降低幅度与盐度突降幅度呈正相关;到实验15天时,死亡率随盐度突降幅度增大而升高。     

Northern Adriatic phytoplankton response to short Po River discharge pulses during summer stratified conditions

A 275‐km‐long transversel Northern Adriatic profile from the mouth of the Po River (Italian Adriatic coast) to the Kvarner region (Croatian coastal island area) was investigated in three successive case studies in August 2008, 2009 and 2010. The short Po River pulses in August result in the surface advection of riverine water, nutrients and phytoplankton from the western to the eastern side of the Adriatic. This surface spreading exhibits inter‐annual variability depending on the riverine discharge in the preceding period. The Po River discharge pulse in August 2010 in particular resulted in an extraordinary tongue‐like advection of riverine water, nutrients, and phytoplankton towards the Eastern Adriatic coast. The phenomenon was detected using both satellite imagery and classical oceanographic measurements. In the advective water, toxic dinoflagellates were most abundant in August 2010, when the influence of the Po was greatest.     

养殖大黄鱼在自然海区降温不同阶段抗氧化水平及血清酶活性的变化

为了解越冬期间水温下降对大黄鱼抗氧化水平和血清酶活性的影响, 作者研究了养殖大黄鱼(Pseudosciaena crocea)冬季海区自然降温不同阶段(20、16、12、10、8℃)肝脏和肌肉中抗氧化水平及血清酶活性的变化。结果显示: 自然降温过程中, 肝脏中3 种抗氧化酶变化趋势不同, 其中SOD 活性呈升高趋势, 8℃时SOD活性最强; POD 活性呈先升高后降低的变化趋势, 16℃时活性最高; CAT 活性呈下降趋势; 而肌肉中这3 种抗氧化酶活性均呈下降趋势。肝脏中GSH 和MDA 含量在16℃时最高; 肌肉中的3 种抗氧化酶活性、GSH 和MDA 含量以及总抗氧化能力(T-AOC)均明显低于肝脏中, 反映了肝脏对清除自由基具有重要作用, 在抗氧化调节方面起到主要作用。血清酶ALT、AST、ALP、LDH 及CK-MB 随水温自然下降酶活性均呈现降低趋势, 即20℃时酶活性最强; CK 和LIP 随着水温降低, 呈先上升再下降的趋势; ADA 和GGT 随水温降低活性呈上升趋势。血清酶的不同变化, 说明水温对大黄鱼血清酶活性有一定的影响。     

Seismic and Petrophysical Relationships from UK Continental Shelf Rocks at Elevated Pressures

Abstract

There are few published seismic (P- and S-waves) properties for seafloor bedrocks. At low pressures (1 to 10 MPa), velocities and attenuations are determined mainly by open microcracks. At higher pressures, the microcracks close, and the velocities and attenuations depend primarily on the matrix porosity. We have investigated both the relationships between the acoustic, petrophysical, and geological properties of the rocks at 40 MPa pressure and the effect of microcracks on the acoustic properties at 10 MPa pressure. In this paper we discuss the former; the latter will be discussed separately.

P- and S-wave velocity and attenuation measurements were carried out on a suite of seabed sedimentary and igneous rocks at effective pressures from 10 to 40 MPa at ultrasonic frequencies. The porosities and permeabilities of the rocks ranged from 0% to 32% and 0 to 110 mDarcy, respectively. Characterization of the rocks revealed that most of the sandstones have a substantial clay content (kaolinite, illite, and chlorite) and fractures. Most of the igneous rocks are chloritized.

The seismic properties of the rocks are markedly lower than those of similar continental rocks because of the microporosity formed by the alteration of feldspars, micas, and mafic minerals to clays (e.g., chloritization of pyroxenes) and the corresponding reduction of the elastic moduli. The results of this study suggest that the values of velocities and quality factors used for ocean acoustic propagation models are lower than normally assumed.     

Composition and Useful Properties of Tailings of Marine Manganese Nodules and Crusts

ABSTRACT

Marine manganese nodules and crusts, when processed, yield tailings which may be utilized for environmental and economic benefit. The key to the reasonable and effective utilization of these tailings lies in making a systematic appraisal of their composition and properties. This article gives an introduction to the investigation of manganese tailings properties. The tailings have a high iron and/or manganese content, high surface area, high porosity, and fine grain size. Some tailings have a high rare earth element content which is valuable. They may also have high SO₃, arsenic, and uranium contents which are harmful. Depending on the process used to produce the tailings, there will likely be some differences in chemical composition, mineral assemblages, surface area and adsorption capability, pore diameter and volume, density and pH. In assigning potentially beneficial applications for these tailings, these differences should be taken into account to optimize utilization.     

济阳坳陷沾化凹陷罗家地区古近系沙河街组页岩储集特征分析*

利用岩石薄片和扫描电镜分析等测试技术, 可以将济阳坳陷罗家地区古近系沙河街组页岩段储集空间分为孔隙和裂缝两大类。孔隙又可以分为黏土矿物晶间孔、碳酸盐矿物晶间孔、黄铁矿晶间微孔、碎屑颗粒溶孔和砂质粒间微孔5个亚类;裂缝分为成岩裂缝和构造裂缝两大类, 成岩裂缝又可以分为层间裂缝和粒缘裂缝两类。裂缝与基质孔隙之间, 存在一个微米尺度的重合带, 反映了储集空间发育继承性的特点, 油气聚集在以层间裂缝为中心, 粒缘裂缝等次级裂缝和较大的碳酸盐晶间孔为骨架, 以各类晶间孔隙、黏土微孔和溶蚀孔隙为基质的储集空间网络中。储集空间发育与岩性关系密切, 纹层状泥质灰岩物性较好, 相应的页岩物性具有基质渗透率极低和裂缝导流能力较强的特点。     

三疣梭子蟹蜕壳后肝胰腺消化酶活力变化特征研究

消化酶是反映机体消化生理状况及对营养物质利用能力的重要指标。本文对三疣梭子蟹蜕壳后不同时间肝胰腺消化酶活力进行了研究,结果显示,蜕壳后肝胰腺中胃蛋白酶、胰蛋白酶和淀粉酶活力在第4~6天达到最高;脂肪酶活力在第6天时达到最高;纤维素酶活力总体较低,在第10~12天达到最高;几丁质酶活力在蜕壳后第4天时酶活力最高。研究表明,三疣梭子蟹蜕壳后,胰蛋白酶和胃蛋白酶活力相对较高,而纤维素酶和淀粉酶活力较低,可能与三疣梭子蟹本身的肉食性特征有关;另外,整个实验期间,三疣梭子蟹肝胰腺脂肪酶活力较低,可能与测定条件有一定的关系。与其他时间点相比,蜕壳后4~6 d(蜕壳周期中间阶段)各种酶活力处于较高水平,表明此阶段对食物的消化能力比其他时间更强,这为养殖过程中饵料的合理投喂提供了参考依据。     

细粒含量对粗粒土冻胀特性影响的试验研究

为了得到同时满足冻胀率和击实效果的最大细粒土含量,通过葡氏击实和冻胀试验,研究了不同细粒土含量、不同干密度条件下细圆砾土填料的冻胀特性。研究结果表明,9%细粒土含量下细圆砾土试样的压实效果最好;细圆砾土试样的冻结过程可以划分为快速冻结区、过渡区、似稳定区和稳定区;细粒土含量低于10%时,细圆砾土属于弱冻胀填料;同时满足冻胀率和压实效果的最大细粒土含量为9%;细粒土含量相同时,细圆砾土试样的冻胀率随干密度的增加,先增大而后减小,即存在一个最不利干密度;冻结48 h后,细圆砾土试样冻土段的含水率均大于初始含水率,其不同位置含水率分布曲线呈S型,且随着细粒土含量的增加逐渐呈现倒三角形分布;细圆砾土试样干密度的增大有效地阻断了水分迁移路径。     

青藏公路沿线土壤微生物数量变化及其影响因素研究

以青藏公路沿线土壤为研究对象, 研究了土壤可培养微生物数量的变化特征及影响因子. 结果表明: 青藏公路沿线土壤可培养微生物数量为0.77×10⁶~2.44×10⁷CFU·g^-1dw; 沿青藏公路从南(申格里贡山)到北(西大滩), 土壤可培养细菌与真菌数量表现为先迅速减少, 然后渐趋平缓; 可培养放线菌数量先减少后增加; 土壤总氮、 有机碳和含水量逐渐降低, 而pH值逐渐升高. C/N比率与真菌/细菌比率变化趋势相似, 均为先增加后减少. 土壤可培养微生物数量与理化因子的相关性分析结果表明: 青藏公路沿线土壤微生物数量主要受纬度和土壤理化性质的影响, 表现为微生物数量与纬度和pH值显著负相关, 而与总氮、 有机碳和含水量极显著正相关.