玉环坎门排污口邻近岩相潮间带生物分布特征

2002年8月对玉环坎门污水处理厂排污口邻近岩相潮间带生物进行定性和定量样品采样,共鉴定出生物57种,其中大型藻类8种、多毛类动物2种、软体动物28种、甲壳类动物13种、棘皮动物1种和其它类动物5种。该排污口邻近两侧岩相潮间带平均生物量为1544.72g/m2,平均栖息密度为3948个/m2。位于排污口左侧的I断面生物量和栖息密度(2406.19g/m2和7415个/m2)明显高于II断面(683.27g/m2和484个/m2),I断面的生物多样性指数(0.91)和均匀度指数(0.39)小于II断面(1.80和0.68);两条断面生物量垂直分布均为中潮区>低潮区>高潮区,I断面栖息密度分布为中潮区>低潮区>高潮区,II断面栖息密度分布为中潮区>高潮区>低潮区。对排污口邻近岩相潮间带生物生态分析表明,该潮间带生物数量的水平分布受海岸开敞度的影响,而垂直分布则与潮区的不同和浪击度的强弱有关。     

石岛大鱼岛村潮间带大型底栖动物生态学研究

根据2008年8月至2009年5月4个季度月(夏、秋、冬、春季),对位于石岛大鱼岛村潮间带的高潮区(SD1站)、中潮区(SD2站)和低潮区(SD3站)所设的3个站进行的大型底栖动物生态调查并分析所获得的资料,采用Shannon-Wiener指数(H’)、物种丰富度指数(D)和物种均匀度指数(J)分析该潮间带不同潮区大型底栖动物的物种多样性。结果表明,石岛大鱼岛村潮间带大型底栖动物的总平均栖息密度、总平均生物量和总种数分别为397.7个/m2,99.874 g/m2和68种。3个潮带的平均密度(D)、平均生物量(B)和种数(S)的季节变化分别为:D冬季>D夏季>D秋季>D春季,B夏季>B冬季>B秋季>B春季,S冬季>S夏季>S秋季>S春季。多样性指数H’值大小顺序为低潮区>高潮区>中潮区,D值大小顺序为低潮区>中潮区>高潮区,J值大小顺序为高潮区>低潮区>中潮区;大鱼岛村潮间带物种多样性指数季节性变化不明显。     

西门岛红树林区大型底栖动物的群落结构

浙南乐清湾西门岛红树林区是中国红树林的最北分布地,为研究该区红树林与底栖动物的生态关系,于2004年5月和8月对红树林区大型底栖动物进行现场采样,共发现大型底栖动物42种,其中软体动物20种、甲壳类11种、多毛类5种、其它类6种。平均生物量和平均栖息密度分别为74.26g/m2和340个/m2,软体动物和其它类动物分别占总生物量的43%和39%,它们的栖息密度分别占动物总栖息密度的66%和30%。红树林区底栖动物的特征种为可口革囊星虫Phascolosomaesculenta,在中潮区其生物量和栖息密度分别高达84.33g/m2和304个/m2。该红树林区底栖动物群落结构的分析结果表明:底栖动物种类与红树林发育状况呈负相关、底栖动物生物量与红树林发育状况呈正相关,红树林主分布区(中潮区)底内群落结构较低潮区简单、生物量高、物种多样性低,而无红树林的低潮区则与之相反,生物量低、种间分布均匀、多样性高。多样性指数低潮区(2.44)>中潮区(1.21)>高潮区(1.0);均匀度指数为0.30～0.73,中潮区为最低。     

砗磲采挖对珊瑚礁生态系统的破坏——以西沙北礁为例

以西沙群岛北礁为例,通过对比采挖砗磲前后的数据,来说明该活动对珊瑚礁生态系统的破坏.2012~2014年间北礁礁坪上的造礁石珊瑚种类数量变动较大,减少了29种;优势种由之前的鹿角珊瑚(Acropora sp.)变为现在的指状蔷薇珊瑚(Montipora digitata);礁坪的物种多样性指数也处于较低的水平.虽然当前北礁的珊瑚覆盖率为52.83%,但是相比2012年降低了大约10%,尤其是2号站位,珊瑚覆盖率降低了约20%.同时2号站位出现了珊瑚白化死亡的现象.调查结果表明,北礁的珊瑚礁生态系统,尤其是礁坪上的珊瑚礁生态系统已经受到严重的破坏,珊瑚种类减少、群落结构改变、物种多样性降低、覆盖率下降、死亡率提高.通过分析,认为砗磲采挖是造成北礁礁坪珊瑚礁生态系统破坏的一个主要因素.     

河北昌黎生态监控区8月潮间带生物多样性年际变化趋势

依据国家海洋环境监测中心2009~2013年测得的数据和资料,对河北昌黎生态监控区潮间带生物的种类组成、栖息密度、生物量、优势种以及多样性指数进行统计运算,分析该监控区5年时间尺度的潮间带生物多样性变化趋势。结果表明:监控区共鉴定出潮间带生物5门,包括节肢动物、环节动物、软体动物、棘皮动物和脊索动物,共17科,26种,类型较少,年际种数呈逐年下降趋势;栖息密度与生物量较低,保持低潮带中潮带高潮带的特征;优势种群变化显著,节肢动物、环节动物和软体动物交替出现,优势种数逐年减少,优势度上升,对其他物种抑制作用增强;均匀度指数(J)呈微上升趋势,变化范围为0.64~0.81,状况良好,物种多样性指数(H′)和丰富度指数(dMa)水平较低,分别为0.81~3.23和0.48~3.96,生物多样性水平呈下降态势。     

大亚湾核电站邻近水域潮间带生物数量与分布

本文分析了大亚湾潮间带生物数量与分布特点,结查表明,其平均生物量为７３２．８５９／ｍ~２,平均栖息密度为 １２３９个／ｍ~２,生物量以藻类居第一位,栖息密度以软体动物居首位。岩石、沙滩和红树林泥滩生态相数量比较,生物量以岩石相最高,栖息密度以沙滩最高。数量垂直分布,生物量和栖息密度均为低潮区＞中潮区＞高潮区。     

山东半岛宁津沿岸潮间带大型底栖动物生态学研究

根据2009年11月至2010年8月4个季度(秋、冬、春、夏)对宁津沿岸潮间带2个断面的高潮带(SC1H与SC2H)、中潮带(SC1M与SC2M)和低潮带(SC1L与SC2L)所设6个站位的大型底栖动物生态调查资料,采用种属组成、优势度指数、物种多样性指数、丰富度指数和均匀度度指数等方法,分析了调查区域内大型底栖动物的生态特征和季节变化。结果表明:宁津沿岸潮间带共采集到大型底栖动物45种,其中甲壳动物为优势类群,共计20种;软体动物14种,环节动物多毛类9种,其他类动物2种。优势种组成方面,甲壳动物钩虾类是4个季度的绝对优势种。调查区域大型底栖动物的年平均生物量为45.09 g/m2;最高生物量出现在秋季,最低出现在春季;空间分布上,除春季外其他三个季度的生物量变化趋势均为中潮带低潮带高潮带。年平均丰度为182.67个/m2;最高丰度出现在夏季,最低出现在冬季。宁津沿岸潮间带大型底栖动物的年平均物种多样性指数H′为1.09,季节变化趋势为冬季秋季夏季春季,空间分布趋势为低潮带中潮带高潮带。与邻近潮间带文献资料相比,调查区域的大型底栖动物在物种数量、生物量和丰度、物种多样性方面均处于低值水平。     

大亚湾核电站邻近水域间带生物数量与分布

本文分析了大亚湾潮间带生物数量与分布特点,结果表明,其平均生物量为７３２．８５ｇ／ｍ＾２,平均栖息密度为１２３９个／ｍ＾２,生物量以藻在居第一位,栖息密度以软体动物居首位。岩石、沙滩和红树林泥滩生态相数量比较,生物量以相最高,栖息密度以沙滩最高。数量垂直分布,生物量和栖息密度均为低潮区〉中潮区〉高潮区。     

庙子湖岛和黄兴岛夏季岩礁潮间带大型底栖动物群落格局

于2009年8月21-22日期间同步调查庙子湖岛和黄兴岛两个岩礁潮间带断面的大型底栖动物种类组成,并分析其群落格局。结果表明,庙子湖岛采集的样品中共有4门28种大型底栖动物,黄兴岛的则有5门37种大型底栖动物;两断面底栖动物群落以广温广布种和亚热带种为主,软体动物作为绝对优势类群主导其分布特征;总平均栖息密度、总平均生物量表现为庙子湖岛＞黄兴岛,种类数及生物量分布均表现为中潮带＞低潮带＞高潮带,栖息密度分布则表现为中潮带＞高潮带＞低潮带;物种多样性指数和物种丰富度指数均为黄兴岛＞庙子湖岛,两断面高潮带的群落生态指数相对中、低潮带较低;大型底栖动物ABC曲线分析表明,庙子湖岛底栖动物群落未受到污染或扰动,黄兴岛底栖动物群落则受到了中等程度的污染或扰动。     

山东半岛镆铘岛潮间带大型底栖动物群落特征

于2007年1月至2007年10月间冬、春、夏、秋4个季度月,对位于山东荣成的镆铘岛潮间带的高潮带、中潮带和低潮带进行大型底栖动物生态调查,根据所获得的样品,对该潮间带不同潮区大型底栖动物的种类组成、平均密度、平均生物量及物种多样性进行了分析.本次调查共采到大型底栖动物92种,其中多毛类环节动物11科22种,软体动物17科28种,甲壳动物18科33种,棘皮动物2科2种,扁形动物1种,腔肠动物2种,鱼类3种;平均栖息密度为329.67个/m2,软体动物贡献最大,其次为甲壳动物;平均生物量为81.74 g/m2,软体动物贡献最大,其次为多毛类环节动物.镆铘岛潮间带多样性指数H'垂直变化规律为高潮带>中潮带>低潮带,季节变化规律为秋季>春季>冬季>夏季.     

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.     

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.     

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.     

《Acta Oceanologica Sinica》Vol. 33(2014) contents

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