象山港人工鱼礁投放对大型底栖动物群落结构的影响

为探明人工鱼礁生境中底栖生物群落结构的组成情况,评估人工鱼礁投放的生态修复效果,根据2006—2007年4季象山港全港区以及2010年4季人工鱼礁区和邻近区的调查资料,对比分析了3个不同区域大型底栖动物群落的差异。共鉴定出大型底栖动物116种,其中多毛类46种,软体动物35种,甲壳类18种,棘皮动物6种,其他类11种,各区域大型底栖动物的主要类群均为多毛类和软体动物。大型底栖动物密度、Shannon-Wiener多样性指数和Margalef丰富度指数表现为邻近区鱼礁区全港区,生物量为鱼礁区邻近区全港区。双因子方差分析结果表明:区域间,大型底栖动物种类数、密度、Shannon-Wiener多样性指数、Pielou均匀度指数和Margalef丰富度指数均存在显著性差异,生物量无显著性差异;季节间,大型底栖动物种类数和密度存在显著性差异,其余参数均无显著性差异。非度量多维尺度排序分析结果显示,鱼礁区和邻近区的大型底栖动物群落相似度较高,而与全港区的相似度较低。相似性百分比进一步揭示,鱼礁区和邻近区大型底栖动物群落间的平均非相似性为77.19%,不倒翁虫(Sternaspis scutata)为造成群落间差异的重要贡献物种;鱼礁区和全港区群落间的平均非相似性高达91.34%,不倒翁虫、薄云母蛤(Yoldia similis)、纵肋织纹螺(Nassarius variciferus)和洼颚倍棘蛇尾(Amphioplus depressus)为重要贡献物种;邻近区和全港区大型底栖动物群落间的平均非相似性也高达91.47%,不倒翁虫、薄片镜蛤(Dosinia laminata)和薄云母蛤为重要贡献物种。双因素相似性分析结果表明,人工鱼礁区、邻近区和全港区大型底栖动物群落季节间存在显著性差异,但区域间无显著性差异。不同区域两两间检验结果表明,人工鱼礁区和全港区的大型底栖动物群落存在显著性差异,人工鱼礁区和邻近区以及邻近区和全港区均无显著性差异。研究结果表明,象山港白石山群岛海域人工鱼礁的投放对大型底栖动物群落结构影响显著,但影响范围局限于人工鱼礁区附近。     

长江口滴水湖大型底栖动物群落结构及其与环境因子的关系

2009年6月—2010年5月,在滴水湖设置8个采样点调查研究了大型底栖动物群落结构特征的时空变化及其与环境因子的关系。在滴水湖共采集到25种大型底栖动物,隶属3门6纲,其中甲壳纲8种(32%)、昆虫纲6种(24%)、寡毛纲和多毛纲各4种(16%)、双壳纲2种(8%)、蛭纲1种(4%)。日本旋卷蜾蠃蜚、微小摇蚊、背蚓虫、黄色羽摇蚊为优势种。底栖动物年均密度和生物量分别为(910.5±107.64)ind./m2和(8.62±2.01)g/m2。底栖动物群落结构包括物种组成、现存量和多样性均无显著季节和空间变化。RDA分析结果表明,活性磷酸盐、叶绿素a、CODMn、pH、溶解氧是影响大型底栖动物物种分布的关键环境因子,日本旋卷蜾蠃蜚、日本大螯蜚、红裸须摇蚊和背蚓虫与溶解氧正相关,与营养盐水平和水温负相关,微小摇蚊和黄色羽摇蚊正好相反。Shannon-Wiener多样性指数和BPI生物指数水质生物学评价表明,滴水湖处于中度污染状态。     

泉州湾蟳埔潮间带大型底栖动物功能群研究

为了比较不同生境的大型底栖动物功能群,根据在泉州湾蟳埔潮间带3种生境类型获得的大型底栖动物数据进行了分析。2011年4月-至2012年1月在泉州湾蟳埔潮间带获得大型底栖动物101种,其中浮游生物食者(Pl)、植食者(Ph)、肉食者(C)、杂食者(O)和碎屑食者(D)物种数分别为21种、18种、21种、26种和15种。光滩(沙滩)、互花米草和牡蛎石三种生境大型底栖动物物种数、平均栖息密度、平均生物量、多样性指数的优势功能群多样化,表明泉州湾蟳埔潮间带大型底栖动物功能群的复杂化和多样化,这种特征是潮汐、生境、底质粒径等环境因子共同作用的结果。潮汐导致潮间带的空间异质性(沉积物粒径的差异),空间异质性导致大型底栖动物功能群组成的差异。互花米草、牡蛎石构成了多种小生境,有利于众多大型底栖动物的栖息。还讨论了大型底栖动物物种鉴定水平和功能群划分标准不同对功能群研究结果的影响。     

象山港游泳动物群落功能群组成与功能群多样性

依据2011年4月、7月和11月象山港水域桁杆拖网和单拖网渔业资源定点调查资料,对象山港水域游泳动物群落的功能群组成及功能群多样性特征进行了系统研究。依据摄食习性,本文将调查海域出现的96种游泳动物划分为7个功能群,其中底栖动物/游泳动物食性、游泳动物食性、底栖动物食性和腐屑食性功能群是该水域的优势功能群。相似性分析检验结果显示:不同季节象山港游泳动物群落的功能群结构保持相对稳定,不存在显著性季节差异。4月、7月和11月该水域游泳动物群落的功能群多样性均值分别为1.303、1.261和1.185,亦未呈现显著性季节差异。功能群多样性指数与大个体生物(体重大于50g)的总重量资源密度显著正相关;功能群多样性与物种多样性的关系可用斜率为0.463、截距为0.266的线性方程进行描述,这表明该水域物种多样性的大量丧失可能引起功能群多样性的降低。象山港水域部分功能群所含物种数明显偏少,冗余度较低,在强大的外界干扰下,某些重要物种的衰退可能将使该水域功能群多样性显著降低。     

弯齿围沙蚕的早期发育

沙蚕属环节动物门多毛纲,主要栖息于海滨泥沙滩和浅海底,是底栖动物群落中的优势种,也是底栖性鱼虾类的主要捕食对象,因而是海洋中的基础饵料动物。素有“万能钓铒”之称的沙蚕,是垂钓渔业的理想钓铒。近年来,在一些发达国家出现了钓鱼热之后,活沙蚕出口的需要量急剧增加。由于供求矛盾的尖锐化,促使了沙蚕人工养殖业的兴起。     

天津近岸海域大型底栖动物摄食功能群特征及其与环境因子的关系

摄食功能群是指生态系统中食性相同的生物群落,研究摄食功能群有助于科学评估区域生态健康状况。基于2015年9月、2016年5月和2016年9月的天津近岸海域大型底栖动物调查数据,结合同步获取的环境因子,分析研究区大型底栖动物摄食功能群组成及其变化特征,探究大型底栖动物摄食功能群组成及变化的原因。结果表明,3个航次的大型底栖动物被划分为5个摄食功能群,但均未发现植食者。3个航次的摄食功能群组成差别不大,但均以碎屑食者和肉食者的物种数和丰度占比最高,杂食者和浮游生物食者的最低;生物量上则是以浮游生物食者和杂食者的占比最高。各类群的物种数和丰度以海河口东沽航道为界,基本呈现北高南低的分布格局。聚类分析结果表明海河口东沽航道内的摄食功能群结构组成与其他区域明显不同,与环境因子多因素方差分析结果一致,说明摄食功能群结构指标能够敏感地响应环境压力。冗余分析和多因素方差分析表明营养盐是影响研究区大型底栖动物摄食功能群结构组成的主要环境因子。与以往研究相比,天津近岸海域大型底栖动物摄食功能群组成状况未发生明显变化,需进一步加强该区域海洋生态保护修复工作,为京津冀一体化经济发展打下坚实的基础。     

渤海大型底栖动物种类组成与群落结构研究

本文利用2008年8月在渤海23个站位采集的样品对大型底栖动物的丰度、生物量、群落结构及其与环境因子的关系进行了研究。共鉴定出大型底栖动物300种,主要类群包括环节动物多毛类、节肢动物甲壳类、软体动物、棘皮动物等。研究海域大型底栖动物的平均丰度为1 094.7ind/m2,平均生物量为11.78g/m2,其中丰度最高区位于辽东湾,最低区位于渤海湾;生物量最高区位于渤海中部,最低区出现在渤海海峡湾口处。依据丰度和生物量进行了CLUSTER聚类和MDS标序图分析,结果可将研究站位划分为6个站组,均与沉积物底质类型密切相关。所研究海域底质类型包括黏土质粉砂、砂、砂质粉砂、粉砂质砂、砂-粉砂-黏土5种。通过BIOENV分析,发现影响大型底栖动物群落结构和分布的主要环境因子有水深、黏土粉砂含量、脱镁叶绿酸含量、叶绿素含量等。与20世纪90年代历史数据的对比发现,本次研究大型底栖动物的物种数目明显减少,平均丰度也减少,特别是优势物种表现出了小型化趋势,传统的大型种类,如心形海胆、双壳类等,被小个体的多毛类和甲壳类所取代。本研究表明渤海近年来受人类活动影响,出现了不同程度的污染,导致大型底栖动物群落结构发生了变化。     

红树林区底栖动物污染生态学研究进展

综述了底栖动物污染生态学研究的现状。目前有关底栖动物的污染生态学研究主要有以下几个方面：（1）污染物在底栖动物体中含量测定及一些污染物在底栖动物中累积分布的研究。（2）污染物对底栖动物生理特性影响的研究。（3）污染物如城市污水对底栖动物群落的影响研究。（4）底栖动物在水质和底质污染中的监测应用。分别综合和评述了红树林底栖动物污染生态学在重金属、城市污水和有机物污染对红树林区底栖动物的生态效应等方面的研究现状。提出今后红树林区底栖动物污染生态学的研究，应着重生态毒理学和实验生态学的研究。     

福建三沙湾网箱养殖对多毛纲动物群落结构的影响

利用东海近海典型网箱养殖海湾三沙湾9个航次数据,基于群落结构时空差异,阐释网箱养殖活动对多毛纲(Polychaeta)动物群落的影响。就群落组成而言,网箱养殖和非网箱养殖水域多毛纲物种组成存在差异,丝鳃虫科(Cirratulidae)和多鳞虫科(Polynoidae)分别是两种水域最占优势的类群;网箱养殖水域多毛纲优势物种的丰度及丰度比值略高于非网箱养殖区(104.06ind./m248.29ind./m2,57.59%46.96%)。双因素方差分析(采样时间和养殖方式)结果表明,两种因素对物种数(S)、丰度(N)、生物量(B)、Shannon-Wiener多样性指数(H′)、Pielou均匀度指数(J′)、Margalef丰富度指数(d)等典型群落参数的交互作用不显著(P0.05);考虑两种因素独立效应时,群落参数均无显著空间差异(P0.05),但存在极显著时间差异(P0.01)。双因素群落结构相似性分析(two-way ANOSIM analysis)表明群落结构无显著空间差异(P0.05),但存在极显著时间差异(P0.01)。典型对应分析(canonical correspondence analysis,CCA)显示pH、水深和溶解氧是影响三沙湾多毛纲动物分布格局的主要环境因子。上述结论显示,三沙湾网箱养殖活动对多毛纲动物群落结构已产生一定影响,主要表现在群落组成方面,群落结构和部分典型底栖环境因子具较强相关性。     

广西北海红树林宜林滩涂大型底栖动物群落结构特征

为了解广西北海红树林宜林滩涂大型底栖动物群落特征,本文首次在北海市选择了2条光滩断面、2条有少量互花米草分布的断面和2条被互花米草覆盖的断面开展生态调查,调查了大型底栖动物的群落结构特征,并分析了其与环境因子之间的关系。结果表明,调查区域大型底栖动物共29种,不同生境的软体动物生物量、节肢动物栖息密度及蟹洞数量差异显著(P<0.05),大型底栖动物的种类组成与沉积物的偏态显著正相关(P<0.05)。光滩样地黄金村HJ群落结构稳定,其余样地大型底栖动物的群落结构均不稳定。互花米草的生长会对大型底栖动物群落结构产生影响。     

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.     

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.     

Deep-Sea Sediment Compression Curves: Some Controlling Factors, Spurious Overconsolidation, Predictions, and Geophysical Reproduction

Oedometer tests have been carried out on 70 undisturbed surficial clays (at approximately 250 mm below the mudline), mostly collected by free-fall corers from sites widely scattered throughout the deep-sea North Atlantic. Acoustic measurements were also made, initially on contiguous samples and ultimately on the same sample using a geophysically instrumented oedometer which also collected electrical resistivity data. Apart from those quiescent areas below the carbonate compensation depth, such as north of the West Indies where very fine clays exist, most of the samples are silty clays whose geotechnical-geophysical properties are dependent on the type of clay minerals present (and their ability to take in moisture), the sand-size fraction, and the quantity of carbonate present. Thus the pure clays have high compressibilities which decrease on the addition of coarse particles, while the converse is true for the acoustic parameters, these increasing with the sand fraction. Using the notion of the intrinsic compression line for all samples, and comparison to it of the measured compression curves, it is clear that, contrary to some previously held ideas, most deep-sea clays are normally consolidated; the addition of carbonate has the effect of creating an open, stronger sediment skeleton. Interestingly, where information is available, the variation with depth of a sample's acoustic velocity follows the void ratio pressure relationship of the compression curve. This allows the construction of an in-situ sediment compression curve using the in-situ geophysical observations.     

Phylogenetic diversity and phenotypic characterization of cultivable bacterioplankton isolated from polar oceans

A set of 27 marine planktonic bacteria isolated from the polar regions was characterized by 16S rDNA sequencing and physiological and biochemical testing. More than half of these bacteria were positive for caseinase, gelatinase and 13-glucosidase, and could utilize glucose, maltose or malic acid as carbon source for cell growth. Twelve isolates expressed nitrate reduction activities. Except for one antarctic isolate BSwlO175 belonging to Actinobacteria phylum, these isolates were classified as γ-Proteobacteria, suggesting that γ-Proteobacteria dominated in cultivable marine bacterioplankton at both poles. Genus Pseudoalteromonas was the predominant group in the Chukchi Sea and the Bering Sea, and genus ShewaneUa dominated in cultivable bacterioplankton in the Prydz Bay. With sequence similarities above 97%, genus Psychrobacter was found at both poles. These 27 isolates were psychrotolerant, and significant 16S rDNA sequence similarities were found not only between arctic and antarctic marine bacteria （ 〉 99% ）, but also between polar marine bacteria and bacteria from other aquatic environments （ ≥ 98.8% ）, including temperate ocean, deep sea, pond and lake, suggesting that in the polar oceans less temperature-sensitive bacteria may be cosmopolitan and have a bipolar, even global, distribution at the species level.     

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.