大连金沙滩小型底栖生物时空分布特征及影响因素

于2015年和2016年对大连金沙滩砂质潮间带进行了季节性的调查,对小型底栖生物及其所处的沉积环境进行了研究,探讨了小型底栖的丰度、生物量和群落的时空变化及其与环境变量的关系。结果表明,金沙滩砂质潮间带沉积物主要成分为极粗砂和粗砂,年平均叶绿素a (Chl-a)质量比为0.99μg/g±1.44μg/g,年平均有机碳质量分数为0.38%±0.56%;共鉴定小型底栖生物类群15个,优势类群为海洋线虫类与底栖桡足类(二者占总丰度72.82%);小型底栖生物年平均丰度为42.52个/cm~2±42.91个/cm~2,呈现明显的季节变化和潮区差异,季节变化趋势为3月10月7月12月,潮区变化趋势为高潮带中潮带低潮带;年平均生物量为87.00μg/cm2±85.32μg/cm~2,季节变化趋势为10月7月3月12月,潮区间也存在显著差异。小型底栖生物的类群组成在季节间具有极显著差异。BIOENV分析表明,间隙水盐度、极粗砂质量比和有机碳质量分数的组合能最好地解释金沙滩小型底栖生物群落的时空分布。研究结果可为砂质滩小型底栖生物的研究提供基础数据,也可为全球气候变化背景下砂质潮间带的保护、开发和利用提供科学依据。     

不同季节东寨港红树林沉积物小型底栖动物的分布特征

于2015-04月(春季)、2015-06(夏季)、2015-10(秋季)、2016-01(冬季),在海南东寨港红树林潮间带沉积物选取15个采样点,进行小型底栖动物定量采样,对小型底栖动物数量分布和类群组成的季节变化特征进行了研究。研究结果表明,小型底栖动物主要包括线虫类、桡足类、多毛类、寡毛类、涡虫类、轮虫类、海螨类。其中,春、夏、秋、冬四个季节线虫平均丰度分别为(192.11±97.87),(203±73.03),(156.25±54.53),(136.74±53.02) ind·10 cm~(-2);桡足类平均丰度分别为(7.68±4.28),(1.14±0.95),(4.43±5.61),(1.99±1.32) ind·10 cm~(-2);多毛类为(1.37±1.17),(0.44±0.47),(0.21±0.24),(0.62±0.71) ind·10 cm~(-2)寡毛类为:(1.30±0.86),(1.35±1.07),(1.27±1.10),(1.46±0.98) ind·10 cm~(-2)。四季中线虫均为优势类群,占94.78%～98.25%,各采样点线虫丰度百分比差别不大,桡足类在春季最大(3.79%),夏季最小(0.55%)。小型底栖动物的分布主要集中在龙尾、长宁尾所对区域及靠近内陆的采样点区域。对不同季节小型底栖动物丰度进行Duncan多重比较,结果显示,春、夏季与秋、冬季小型底栖动物类群丰度存在显著差异。对不同季节不同类群的小型底栖动物丰度进行Student-Newman-Keuls多重比较,结果显示,春、夏季与秋、冬季线虫类丰度存在显著差异;桡足类丰度夏、冬季节不存在显著性差异,秋、冬季节不存在显著性差异,其余季节之间均存在显著性差异;多毛类丰度春、夏、秋、冬四季均存在显著性差异;而寡毛类丰度不同季节均无显著差异。     

台湾海峡中北部海域春季小型底栖生物丰度和生物量

2009年4月14～16日在台湾海峡中北部海域进行了小型底栖生物调查研究.结果表明,研究海域的小型底栖生物平均丰度为21.11±16.29 ind/cm^2;平均生物量为20.97±4.96μg/cm^2（以干重记）.研究海域共鉴定出13个小型底栖生物类群,按丰度,最优势类群为自由生活海洋线虫其丰度为19.23±15.49 ind/cm^2,占小型底栖生物总丰度的91.10%,其他优势类群依次为底栖桡足类和多毛类,分别占小型底栖生物总丰度的2.77%和2.64%;分布在0～5 cm的表层沉积物内的小型底栖生物约为83.18%,线虫和底栖桡足类分布在0～2 cm的比例分别为57.66%和62.96%.小型底栖生物的生物量低于大型底栖生物,但由于其繁殖快,生命周期短,因此,其生物量约为大型底栖生物的445倍,年平均生产量约为大型底栖生物的1.39倍.     

青岛太平湾砂质潮间带小型底栖生物丰度和生物量的研究

于2004年10月~2005年10月对青岛太平湾砂质潮间带进行了小型底栖生物的逐月采样,对丰度和生物量进行定量研究。结果表明,小型底栖生物的年平均丰度为(1 025.40±268.84)ind.10cm-2,平均生物量为(1 195.87±476.53)μgdwt.10cm-2,平均生产量为(10 762.80±4 288.77)μg dwt.10cm-2a-1。小型底栖生物在丰度和生物量上呈现了明显的季节变化,高值主要出现在4,5,6月,而低值在8,9月。共鉴定出l2个类群,线虫在丰度上占绝对优势(89.2%)。按生物量,多毛类占46.9%,其次为线虫31%。其它较多的类群还有涡虫、桡足类、腹毛虫、寡毛类等。50%以上的小型底栖生物分布在0~4cm表层,冬季部分向下迁移。Pearson相关分析表明,小型底栖生物数量对间隙水溶氧表现出明显的滞后效应,而与盐度、pH和沉积物环境因子相关性不明显。     

南大西洋洋中脊调查区小型底栖生物丰度和生物量研究

“大洋一号”调查船于2011年5—6月在南大西洋中脊14°S附近进行了7个站位的小型底栖生物采样。共鉴定出小型底栖生物10个类群。小型底栖生物平均丰度为(60.63±54.77) ind/10 cm²,平均干重生物量为(9.42±8.92) μg/10 cm²。线虫是其中的优势类群,丰度为(47.42±47.99)ind/10 cm²,占总丰度的78.21%,另外,肉鞭动物和桡足类分别占总丰度的16.63%和3.91%。生物量前3位的类群依次为桡足类、线虫和肉鞭动物。小型底栖生物密度随沉积物深度增加而减少,约73.55%的生物丰度分布在0～2 cm层内。个体大小方面,有75.32%的小型底栖生物粒径处于32～125 μm范围内。     

青岛薛家岛砂质潮间带小型底栖生物丰度和生物量

于2008和2009年对青岛薛家岛砂质潮间带进行了4个季度的小型底栖生物调查。结果表明:小型底栖生物的平均丰度为(1 384.69±424.97)ind·10cm-2,平均生物量为(1 286.70±225.13)μg·10cm-2。共鉴定出11个类群,丰度方面,线虫占绝对优势,占年平均丰度的86.59%;涡虫居次,占4.89%。生物量方面,线虫也占绝对优势,占37.30%;多毛类居次,占18.90%。在垂直分布上,表层0~4cm的数量最多,占39.65%,其它各层分布依次递减。小型底栖生物的丰度和生物量呈现了明显的季节变化和潮区差异。相关分析未表明小型底栖生物丰度和环境的显著相关性。     

莱州湾和牟平近海夏季小型底栖生物群落组成及环境状况分析

为探究莱州湾和牟平近海小型底栖生物群落组成及影响因子,作者于2016年7月在这两个海域采集了沉积物样品,并结合沉积环境因子进行了小型底栖生物群落组成分析。结果表明,在莱州湾和牟平近海各仅检获了7个小型底栖生物类群,且莱州湾的小型底栖生物平均丰度和生物量均明显低于牟平近岸海域。莱州湾线虫和桡足类平均丰度分别占小型底栖生物的91.9%和6.3%,牟平近海分别占92.1%和4.2%。对两个海域小型底栖生物群落组成与环境因子进行Pearson相关性分析,结果显示:小型底栖生物丰度与底层水溶解氧含量呈显著正相关;表层小型底栖生物丰度比与沉积物中叶绿素a含量、脱镁叶绿素含量、沉积物有机质含量以及水深呈显著正相关,与中值粒径和底层水温度呈显著负相关。本研究显示,基于不同沉积物类型中的参考比值,线虫和桡足类丰度比值(N/C)可用于莱州湾和牟平近海沉积环境有机污染状况的评估。研究还发现,牟平海域的小型底栖生物丰度和生物量呈现由近岸向外海增加的异常趋势,且小型底栖生物的数量和类群多样性较十年前显著降低,显示沉积环境受到了明显干扰。     

北黄海小型底栖生物丰度和生物量时空分布特征

分别于2006年7月和2007年1,4和10月在北黄海陆架浅海水域进行小型底栖生物调查.结果表明,4个航次的小型底栖生物平均丰度分别为(1 099±634),(664±495),(1 601±837)和(524±378) ind·10 cm-2;平均生物量分别为(1 446.34±764.66),(428.63±294.84),(1 580.53±1 041.23)和(793.50±475.83) μg·dwt·10 cm-2.共鉴定出18个小型底栖生物类群,按丰度,自由生活海洋线虫为最优势类群,4个航次的优势度分别为72%,90%,85%和74%,其他优势类群依次是桡足类、多毛类、动吻类和介形类;按生物量依次是线虫、桡足类、多毛类、介形类和双壳类.97%的小型底栖生物分布在0～5 cm的表层沉积物内,线虫和桡足类分布在0～2 cm沉积物的比例分别为86%和87%.二因素方差分析(two-way ANOVA)表明:小型底栖生物丰度和生物量在由4个航次所代表的春、夏、秋、冬各季节之间存在显著差异(春、夏高于秋、冬),在4个航次的5个相同取样站位之间也有显著差异.小型底栖生物的丰度和生物量与水深和底盐呈负相关性.北黄海冷水团对小型底栖生物丰度和生物量时空分布有一定的影响.     

长江口及邻近陆架海区夏季小型底栖动物群落结构研究

根据2006年7月13日至8月30日在长江口及邻近陆架海区采集的小型底栖动物样品,对小型底栖动物类群组成,丰度、生物量的水平分布和垂直分布以及调查海区的环境因子进行了研究。结果表明：研究海域小型底栖动物有线虫、桡足类、多毛类、寡毛类、介形类、螨类、双壳类、腹毛类、动吻类、端足类和等足类等11个类群及无节幼体等。平均丰度为453.22±355.34 ind/10 cm2,最优势类群为线虫,占小型底栖动物总丰度的81.37%,次优势类群分别为底栖桡足类和多毛类,分别占小型底栖动物总丰度的10.13%和2.96%。平均生物量为622.65±505.07 μg/10 cm2,生物量占比最高的类群为多毛类,占总生物量的30.21%,其次分别为线虫和寡毛类,分别占小型底栖动物总生物量的23.69%和19.44%。水平分布上,从河口冲淡水区到东海陆架深水区,小型底栖生物丰度呈现由低到高的变化趋势,杭州湾小型底栖动物丰度为240.96±223.47 ind/10 cm2,长江口近岸区为442.91±304.16 ind/10 cm2,东海陆架深水区为865.42±553.88 ind/10 cm2。垂直分布上,小型底栖动物主要分布在0~2 cm层,丰度为290.28±250.03 ind/10 cm2;其次是2~5 cm层,丰度为132.81±128.74 ind/10 cm2;5~10 cm层分布最少,丰度为30.14±31.91 ind/10 cm2。其中线虫、多毛类、寡毛类与桡足类等主要类群的垂直分布与总分布趋势相同。与环境因子进行相关分析表明,调查海区小型底栖动物的丰度主要与水深、盐度和溶解氧显著相关,对小型底栖动物分布影响最大的环境因子组合为溶解氧和盐度。     

青岛三种岩礁海藻附植小型底栖生物的初步研究

2013年6月-2014年6月对青岛岩礁潮间带鼠尾藻、孔石莼、蜈蚣藻附植小型底栖生物进行了连续13个月的逐月采样,对小型底栖生物的丰度、生物量、生产量、类群组成及其季节动态进行了研究。共鉴定出小型底栖生物16个类群。鼠尾藻附植小型底栖生物的年平均丰度和生物量分别为7×103 ind·g-1 dwt algae·a-1和56×103μg·g-1 dwt algae·a-1。孔石莼附植小型底栖生物的年平均丰度和生物量分别为2×103 ind·g-1 dwt algae·a-1和8×103μg·g-1 dwt algae·a-1。蜈蚣藻附植小型底栖生物的年平均丰度和生物量分别为3×103 ind·g-1 dwt algae·a-1和16×103μg·g-1 dwt algae·a-1。三种藻类附植小型底栖生物平均丰度和生物量的高低依次为:鼠尾藻蜈蚣藻孔石莼。附植小型底栖生物及其主要类群的丰度具有明显的季节变化,其中鼠尾藻、孔石莼附植小型底栖生物丰度与海水温度和盐度显著相关。附植小型底栖生物的丰度还可能与藻类生长周期关系密切,三种藻类附植小型底栖生物的丰度的最高值均出现在藻类的快速生长期之前。三种藻类附植小型底栖生物群落差异显著,鼠尾藻上线虫为最优势类群,孔石莼和蜈蚣藻上底栖桡足类为最优势类群。藻类形态和藻类生活周期是影响附植小型底栖生物类群组成、丰度和生物量的关键因素。     

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.     

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.     

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.     

INFORMATION FOR AUTHORS

<正>Acta Oceanologica Sinica(AOS)is a comprehensive academic journal edited by the Editorial Committee of Acta Oceanologica Sinica and is designed to provide a forum for important research papers of the marine scientific community which reflect the information on a worldwide basis.The journal publishes scholarly papers on marine science and technology,including physics,chemistry,biology,     

Net Sand Transport Direction in a Tidal Inlet, using Foraminiferal Tests as Natural Tracers

The relationship between the flux of exotic benthic foraminiferal tests (i.e. tests which are supplied from open-sea sources alone) in a tidal inlet and that of bulk sediment was analysed, which can be expressed as two first-order linear equations. According to this relationship, in order to determine net sediment transport directions in the entrance, the test concentration in surficial sediments of the tidal basin can be compared against a ‘ critical level ’. The critical level is determined for the conditions that no net transport of bulk sediment is present within the entrance. If the observed concentration (averaged over the tidal basin) is higher than the simulated critical level, then the net sediment transport is directed to landward. This method is applied to the analysis of net sand transport at Christchurch Harbour, a tidal inlet system located in southern England. In this investigation, concentrations of exotic foraminiferal tests in the surficial sediments of the tidal basin and ebb tidal delta area were obtained from the analysis of sea-bed sediment samples. A series of probable critical levels were calculated based upon the data sets with regard to: (1) sediment discharge from the rivers; (2) magnitude of sediment discharge within the entrance during the ebb; (3) the test concentration outside the harbour; (4) the thickness of the moving layer; and (5) two parameters associated with dispersive processes. The results show that the concentration in the tidal basin sediment is higher than a number of simulated critical concentrations for representative cases. Consequently, the high level of the concentration of exotic benthic foraminiferal tests within the harbour should be explained as a result of landward net transport of sands within the entrance.     

Dynamic behaviour of axially pre-loaded tubular steel members of offshore structures subjected to impact damage

The behaviour of an axially pre-loaded cylindrical member of an offshore structure, hit by a supply ship, has been investigated. The effects of axial pre-loading on the dynamic properties of members, the extent of damage and propagation of dynamic instability in the tubular members have also been investigated. Numerical models have been validated using available experimental data from the literature although these are mostly static with no pre-loading. Axial pre-loading was found to change the dynamic characteristics of some cylindrical members quite dramatically while it had no significant effect on others. The study examined whether there was any change in the behaviour between local and global modes when the loading was dynamic rather than static. The effect of damping on the dynamic instability of axially pre-loaded tubes under lateral dynamic loads was also studied. It was observed that for some geometries the quasi-static response can be used to define the boundary between bounded and unbounded dynamic responses. The main contribution of this study, compared with previous investigations reported in the literature, is that both pre-loading and dynamic effects have been included.     

Assessment of Impact on Seafloor Features in INDEX Area

Observations on seafloor features from subbottom profiling and seabed photography data show that the undisturbed and natural conditions before the benthic disturbance undergo a substantial change after operation of the disturber. The effects can be seen in the form of deep trenches and grooves, formed by the action of the sleds and the pumping of the sediment along its path, as well as sediment piles on either side of the track. Biological traces such as fecal coils, casts, tubes, burrows, and trails get obliterated in the areas of disturbance and resedimentation. The smooth, uniform nature of the seafloor observed in predisturbance phase shows microtopographic changes in and around the disturbed area as a result of sediment excavation and resettlement. Vertical mixing as well as lateral transport of sediment alter the geological, biological, physical, and chemical conditions on the seafloor, which need to be monitored over time to assess the process and the time taken for restoration of environmental conditions.     

Regional Commercial Sponge Extinctions in the West Indies: Are Recent Climatic Changes Responsible?

Abstract. Long-term changes in the distributional patterns of commercial sponges ( Spongia spp. and Hippospongia spp.) within the West Indian Region indicates that: 1) commercial sponges had a widespread distribution throughout the whole West Indian Region and were ubiquitous in very shallow water until about the first half of the present century; 2) they were fished commercially not only in the traditional northern Caribbean sites (Florida, Gulf of Mexico, Bahamas) but also in the Greater ( e. g. , Hispaniola, Jamaica) and Lesser Antilles; and 3) they became extinct throughout most of the Lesser Antilles ( e. g. , Puerto Rico, Vieques, St. Thomas) sometime during the first half of this century. Mortalities of spongiids within the Antilles were found to differ from other marine mortalities in that: 1) species disappeared from a large region; 2) species vanished from different habitats and depths; and 3) natural populations never recovered. Species richness patterns suggest that commercial sponge genera ( Spongia and Hippospongia ) evolved under slightly cooler elimatic conditions than those found at present, and that these extinctions occurred as a direct or indirect effect of positive thermal anomalies in sea surface and atmospheric temperatures between 1900–1950. The concept that species diversity is stable on a regional scale is questioned.