淡水白鲳幼鱼盐碱耐受性的初步研究

通过淡水白鲳（ＣｏｌｏｓｓｏｍａｂｒａｃｈｙｐｏｍｕｍＣｕｖｉｅｒ）幼鱼（Ｌ＝２．９ｃｍ±０．０５ｃｍ）对氯化钠浓度（ｐＨ＝８．２１±０．０７）及碱度（ｐＨ＝８．８５±０．１８）的急性毒性试验。用概率单位法求得其２４、４８、９６ｈ的半致死浓度（ＬＣ５０）：氯化钠浓度分别为１２．０、１１．４、１０．４ｇ·Ｌ－１;碱度分别为８３．２５、５６．９９、４５．７０ｍｍｏｌ·Ｌ－１,并在此基础上进行盐碱混合正交试验,经统计分析得出碱度致死作用显著。在此条件下２４ｈＬＣ５０值时碱度与氯化钠浓度的关系为：Ａｌｋ（ｍｍｏｌ·Ｌ－１）＝２５６．２４－２４．６９Ｓａｌ（ｇ·Ｌ－１）。     

中国对虾对日本刺沙蚕的摄食率研究

于１９９６年６月在山东莱阳市养殖场采集中国对虾（体长４．５－６．０ｃｍ体重１．２－３．７ｇ）和日本刺沙蚕（体长１．０－５．０ｃｍ）通过持续２０的室内实验,研究中国对虾对日本刺沙蚕的摄食率,实验条件为：水温２１－２３℃,海水盐度３０－３１,ｐＨ＝８．２－８．６,室内自然光照,实验结果表明,中国对虾对日本刺沙蚕的摄食率Ｃ（ｇ．ｇ＾－１．ｄ＾－１）与体重Ｗ（ｇ）的关系为Ｃ＝０．１５３Ｗ＾０．７０７２,在     

珠江口海水碱度研究

采用ｐＨ 电测法测定了珠江口区表层海水碱度。发现珠江河口区表层海水碱度,在盐度０ ．０８０～２５．７２２ 范围内,变化范围为０．６７０ ～１ ．９４ｍｍｏｌ·ｄｍ － ３ ,碱度平均值为１ ．４３ ±０ ．３３ｍｍｏｌ·ｄｍ － ３ 。相应比碱度变化范围为０．１０６ ～６８ ．６６７ ,平均为１１ ．３ ±２２ ．６ 。自湾北到湾外碱度随盐度增大而增大,与盐度呈密切正相关。并讨论了比碱度、碳酸碱度与硼酸碱度的分布变化。     

亚硝酸盐对长毛对虾幼体的毒性

长毛对虾幼体从无节幼体至仔虾期对亚硝酸盐的忍耐性依次增强。在盐度３２，ｐＨ８．２０和水温２８±０．５℃的条件下，无节，蚤状，糖虾，仔虾２４ｈ的ＬＣ５０值分别为７．６３，１５．０９，２２．９２和６４．５８ｍｇ／ｄｍ＾３ＮＯ２２－Ｎ；蚤状，糖虾，仔虾４８ｈ的ＬＣ５０值分别为１１．９，１１．４１和３７．３４ｍｇ／ｄｍ＾３ＮＯ２－Ｎ；仔虾７２ｈ和９６ｈ的ＬＣ５０值分别为２２．９４和１３．８１ｍｇ／ｄｍ＾３     

氨对长毛对虾幼体的毒性

氨对长对虾各期幼体的毒性试验表明：蚤状幼体对氨最每天敏感，而仔虾幼体对氨的耐受性最强，在盐度３２，ＰＨ８．２０，水温２９．０℃时，无节幼体Ⅱ期，蚤状幼体Ⅰ期，仔虾第五天２４ｈ的ＬＣ５０值分别为１３．２０（１．１５）、９．９７（０．８７）、２６．９９（２．３５）和６０．８１ｍｇ／ｄｍ＾３ΣＮＨ＾＋４（ＮＨ３）－Ｎ＾１（５．３０ｇｍ／ｄｍ＾３ＮＨ３－Ｎ）．Ｚ１，Ｍ１，Ｐ５的４８ｈ的ＬＣ５０值分别为５．     

温盐度对斜带髭鲷孵化率及仔鱼存活率的影响

本文对不同温、盐度梯度下斜带髭鲷的孵化情况进行探讨,结果表明：（１）斜带髭鲷的适宜孵化温度为１９－２５℃,最知温度为２３－２５℃。（２）适宜盐度为１６．３－３４．７,最适盐度为２４．２－３２．１,尤以２９．５为好。（３）当温度为２３℃,直２９．５,ＰＨ值为８．１－８．３时,幼体孵化率最高,达９３．３％,（４）温度２２．６－２３．４℃,盐度２４．２－３２．１,４２ｈ孵出的仔鱼至５２ｈ存活率高于８１     

杭州湾海水碱度研究

用ｐＨ法测定了杭州湾海水的碱度。结果表明,１９９４ 年５ 月份,杭州湾海水在盐度１２ ．０９７～２６ ．３９７ 之间的碱度变化范围为１．５５ ～２．２３ｍｍｏｌ．ｄｍ － ３ ,平均值为１ ．７５７ｍｍｏｌ．ｄｍ － ３ 。相应的比碱度变化范围为０．１０６ ～０ ．３２４,平均值为０．２０２ ． 碱度高值出现在北岸上海石化总厂附近。因受北岸工业废水排放影响,湾内碱度自西北向东南降低。丰水期湾内海水比碱度显著增大,主要受径流的影响。枯水期湾内碱度和比碱度与盐度或氯度呈负相关关系。     

厦门西港表层沉积物中DDTs，HCHs和PCBs的含量与分布

对厦门西港表层沉积物中有机氯农药和多氯联苯的含量与分布进行调查研究。含量范围：ＨＣＨｓ为０．１４－１．１２ｎｇ·ｇ（－１），ＤＤＴｓ４．４５３１１ｎｇ·ｇ（－１），ＰＣＢｓ０．０５—７．２４ｎｇ·ｇ（－１）。与香港维多利亚港表层沉积物含量进行比较，厦门西港表层沉积物的ＰＣＢＳ含量低于维多利亚港，ＤＤＴｓ含量则高于维多利亚港。     

厌氧接触消化技术处理高浓度淀粉废水研究

实验采用厌氧接触消化技术，分别在中温（３２℃）和自然温度条件下处理淀粉厂的高浓度废水。结果表明，采用中温厌氧消化可取得较好的处理效果，原水不调ｐＨ（原水ｐＨ为４．０～４．９）直接进反应器，容积负荷最高达５．０６ｋｇＣＯＤｃｒ／ｍ３·ｄ，进水ＣＯＤｃｒ平均１１．６０４×１０３ｍｇ／ｌ，出水ＣＯＤｃｒ平均１．７７８×１０３ｍｇ／ｌ，ＣＯＤｃｒ去除率达８５．８％，出水ｐＨ提高到６．４～７．０。采用自然温度消化，当气温大于２４℃时，可取得较好的处理效果     

庙岛群岛海域光棘球海胆生态的初步研究

庙岛群岛的光棘球海胆主要分布于北四岛（南、北隍城岛,大、小钦岛）,砣矶岛及大、小竹山岛等,而南五岛极少分布。砣矶岛的海胆多是２～３年生壳径４～６ｃｍ的个体,海胆性腺成熟期为７月中旬至８月中旬,性腺发育与水温、栖息场和饵料等有关。海胆体重随季节而变化,繁殖季节体重Ｗ（ｇ）与壳径Ｄ（ｃｍ）相关,Ｗ＝２．５８２Ｄ２．０３４（ｒ＝０．８７）,性腺重ＧＷ（ｇ）与壳径Ｄ（ｃｍ）关系为ＧＷ＝０．０４０３Ｄ３．０８２８（ｒ＝０．８２７３）,壳径Ｄ（ｃｍ）与壳高Ｈ（ｃｍ）呈线性关系Ｈ＝０．５２２５Ｄ＋０．０６６８（ｒ＝０．９０７８）。壳径生长随年龄而变慢,２．８ｃｍ的幼海胆年增长２．１ｃｍ;６．１ｃｍ的成海胆年增长０．４３ｃｍ。光棘球海胆嗜食海带和裙带菜,平均日摄食量６．０ｃｍ的海胆为２．６ｇ,４．０ｃｍ的为１．３４ｇ,３．１ｃｍ的为１．３ｇ,幼海胆摄食率较高的原因是因其生长发育快速,活动强度和代谢水平高。     

Microbial Biomass and Organic Nutrients in the Deep-Sea Sediments of the Central Indian Ocean Basin

In order to assess the impact of deep-sea mining on the in situ benthic life, we measured the microbial standing stock and concentration of organic nutrients in the deep-sea sediments of the Central Indian Ocean Basin in the Indian pioneer area. Sediments were collected using box core and grab samples during September 1996. The total bacterial numbers ranged from 10 10 -10 11 cells per g -1 dry weight sediment. There was a marginal decrease in the number of bacteria from surface to 30 cm depth, though the subsurface section registered a higher number than did the surface. The highest numbers were encountered at depths of 4-8 cm. The retrievable number of bacteria were two orders less in comparison with the direct total counts of bacteria. An almost homogeneous distribution of bacteria, total organic carbon, living biomass, and lipids throughout the depth of cores indicates active microbial and benthic processes in the deep sea sediments. On the other hand, a uniform distribution of total counts of bacteria, carbohydrates, and total organic carbon in all the cores indicates their stable nature and suggests that they can serve as useful parameters for long-term monitoring of the area after the benthic disturbance. Further studies on temporal variability in this region would not only verify the observed norms of distribution of these variables but would also help to understand restabilization processes after the simulated benthic disturbance.     

Assessing the Validity of Seismo-Acoustic Predictor Equations for Obtaining Seabed and Sub-Surface Sediment Physical Properties

The interdependence between the seismo-acoustic properties of a marine sediment and its geotechnical/physical parameters has been known for many years, and it has been postulated that this should allow the extraction of geotechnical information from seismic data. Though in the literature many correlations have been published for the surficial layer, there is a lack of information for greater sediment depths. In this article, a desktop study on a synthetic seafloor model illustrates how the application of published near-surface prediction equations to subsurface sediments (up to several tens of meters burial depth) can lead to spurious predictions. To test this further, acoustic and geotechnical properties were measured on a number of sediment core samples, some of which were subjected to loading in acoustically-equipped consolidation cells (oedometers) to simulate greater burial depth conditions. For low effective pressures (representing small burial depths extending to around 10 meters subsurface), the general applicability of established relationships was confirmed: the prediction of porosity, bulk density, and mean grain size from acoustic velocity and impedance appears generally possible for the investigated sedimentary environments. As effective pressure increases through, the observed relationships deviate more and more from the established ones for the near-surface area. For the samples tested in this study, in some instances increasing pressure even resulted in decreasing velocities. There are several possible explanations for this abnormal behavior, including the presence of gas, overconsolidation, or bimodal grain size distribution. The results indicate that an appropriate depth correction must be introduced into the published prediction equations in order to obtain reliable estimates of physical sediment properties for greater subsurface depths.     

A Review of Some Environmental Issues Affecting Marine Mining

This article reviews information recently available from existing marine and coastal mining for responses to environmental issues affecting marine mining at different depths. It is particularly but not exclusively concerned with those issues affecting seabed biodiversity impact and recovery. Much information has been gathered in the past 10 years from shallow mining operations for construction aggregate, diamonds, and gold, from coastal mines discharging tailings to shallow and deep water, and from experimental deep mining tests. The responses to issues identified are summarized in a series of eight tables intended to facilitate site-specific consideration. Since impacts can spread widely in the surface mixing layer SML, and can affect the biologically productive euphotic zone, the main issues considered arise from the depth of mining relative to the SML of the sea. Where mining is below the SML, the issue is whether it is environmentally better to bring the extraction products to the surface vessel for processing (and waste discharge), or to process the extraction products as much as possible on the seabed. Responses to the issues need to be sitespecific, and dependent on adequate preoperational environmental impact and recovery prediction. For deep tailings disposal from a surface vessel, there are four important environmental unknowns: (1) the possible growth of "marine snow" (bacterial flocs) utilizing the enormous quantities of fine tailings particles (hundreds or thousands of metric tons per day) as nuclei for growth, (2) the possibility that local keystone plankton and nekton species may migrate diurnally down to and beyond the depth of deep discharge and hence be subjected to tailings impact at depth, (3) the burrow-up capability of deep benthos and their ability to survive high rates of tailings deposition, and (4) the pattern and rate of dispersion of a tailings density current through the deep water column from discharge point to seabed. Actions to obtain relevant information in general and site-specifically are suggested.     

Increased Particle Fluxes at the INDEX Site Attributable to Simulated Benthic Disturbance

Particle fluxes were measured 7 m above the sea bottom during the predisturbance, disturbance, and postdisturbance periods by using time series sediment traps attached to seven deep-sea moorings deployed in the INDEX experiment site in the Central Indian Basin. The predisturbance particle fluxes varied between 22.3 to 55.1 mg m -2 day -1 . Increased and variable particle fluxes were recorded by the sediment traps during the disturbance period. The increase observed was 0.5 to 4 times more than the background predisturbance fluxes. The increases in particle fluxes (~4 times) recorded by the sediment trap located in the southwestern direction (DMS-1) were the greatest, which could be the result of preferential movement of resuspended particles generated during the deep-sea benthic disturbance along the general current direction prevailing in this area during the experimental period. Also, the traps located closer to the disturbance area recorded greater fluxes than did the traps far away, across the Deep Sea Sediment Resuspension System path. This variability in recorded particle fluxes by the traps around the disturbance area clearly indicates that physical characteristics such as grain size and density of the resuspended particles produced during the disturbance had an important effect on particle movement. The postdisturbance measurements during ~5 days showed a reduction in particle fluxes of ~50%, indicating rapid particle settlement.     

海上大直径钢管桩打桩过程中桩周土强度弱化研究

海上大直径钢管桩打桩过程中,桩周土体受到强烈扰动而发生强度弱化,掌握桩周土体强度弱化规律对于准确预测打桩过程、保证工程安全具有重要意义。为研究土体强度弱化规律,开展了环剪试验模拟打桩对桩周土体的扰动,测试土体强度随剪切速率的变化规律,建立了描述土体强度弱化规律的拟合公式,引入到打桩分析软件中。研究结果表明：土体的强度折减程度不仅与土体本身的性质有关还受到土体的埋深和剪切速率的影响,埋深越深土体强度折减程度越低,剪切速率越高土体强度折减越高,在打桩分析中可采用这里推荐的线性折减方法来模拟不同深度处土体强度的折减规律。     

Geoacoustic Inversion via Genetic Algorithm and Its Application to Manganese Sediment Identification

An acoustic inversion method using a wide-band signal and two near field receivers is proposed and applied to multiple layered seabed models including a manganese sediment. The inversion problem can be formulated into a probabilistic model comprised of signals, a forward model, and additive noise. The forward model simulates wide-band signals, such as chirp signals, and is chosen to be the source-waveletconvolution plane wave modeling method. The wavelet matching technique, using weighted least-squares fitting, estimates the sediment sound-speed and thickness on which determination of the possible numerical ranges for a priori uniform distribution is based. The genetic algorithm is applied to a global optimization problem to find a maximum a posteriori solution for determined a priori search space. Here the object function is defined by an L 2 norm of the difference between measured and modeled signals. Not only the marginal pdf but also its statistics are calculated by numerical evaluation of integrals using the samples selected during importance sampling process of the genetic algorithm.     

Interannual Sea Level Variations and Annual Tides in the Northwestern Pacific

Specific properties of the interannual sea level variations and annual tides in the Northwestern Pacific were studied. Several tide stations were monitored. The monthly mean sea level for the year of 1995 was analyzed at each tide station. A seismic event in 1995, some tectonic activity around the subject area, and the Kuroshio (the oceanic western boundary current) may possibly contaminate results which would have occurred from the astronomical annual tide alone.     

Determination of In Situ Sediment Shear Strength from Advanced Piston Corer Pullout Forces

The advanced piston corer (APC) has been used by the Ocean Drilling Program since 1985 for recovering soft sediments from the ocean floor. The pullout force measured on extracting the core barrel from the sediment is shown to correlate with the average shear strength of the sediment core measured in the ship's laboratory. A simple rule of thumb is derived relating the shear strength of the sediment to the pullout force. Multiple APC holes at individual sites allow the consistency of the pullout measurements to be assessed. The effects of different operational procedures during APC coring are also explored. Although generally applicable, the correlation between pullout force and laboratory measurements of shear strength breaks down for some APC holes, possibly because of the disturbance of some sediment types during the APC coring process. A better understanding of the physical process of APC coring, and its effect on the properties of the sediment both inside and immediately outside the core barrel, would indicate what confidence can be put on the measurement of pullout force as a way of evaluating the in situ shear strength of deep sea sediments.     

Flow Cytometric Analysis of Coastal Lagoon Bacterioplankton and Picophytoplankton: Fixation and Storage Effects

The effect of different fixation and storage protocols on the flow cytometric (FCM) simultaneous analysis of bacterioplankton and phytoplankton in coastal seawater samples (Mediterranean coastal lagoons) was investigated. FCM measurements (cell number, fluorescence and scatter characteristics) were obtained through DAPI staining. Three fixatives [glutaraldehyde (GA), formaldehyde (FA) and paraformaldehyde (PFA)] and two storage (3 months duration) methods (5 °C and −196 °C) were tested. Two dominant populations were detected in studied samples: bacteria and eukaryotic picophytoplankton. Adding fixatives (2% final concentration) appears necessary to obtain FCM exhaustive counts of all the bacteria and phytoplanktonic cells. This was related to the permeation effect of fixatives which allowed a better DAPI staining of the cells. Maximum fluorescence, i.e. optimal staining of the cells was obtained with FA or PFA, and significant lower fluorescences with GA. Fixed samples stored at 5 °C induced rapid cell loss. Only storage in liquid nitrogen of samples fixed with FA or PFA, allows mid-term (≥4 months) preservation of bacteria or picophytoplankton cell numbers, and limited evolution of DAPI-induced fluorescence and scatter characteristics.