浒苔和马尾藻的生消与海表面温度的相互影响研究

温度是影响藻类生长繁殖的一个重要因素。本文针对2013年6月在黄海海域出现的大量浒苔和马尾藻事件,基于MODIS(Moderate-Resolution Imaging Spectroradiometer)卫星遥感数据,分析了此次事件中浒苔和马尾藻生消过程与海表面温度之间的关系。首先根据浒苔、马尾藻和水体的光谱特征曲线,本文利用大型浮游藻类指数(Macroalgae Index,MI)对浒苔和马尾藻进行了识别,并且对浒苔和马尾藻生消过程中的MI值和对应的海表面温度进行了分析,结果表明:在此次事件中,海水温度是影响浒苔和马尾藻生长繁殖的重要环境因子,浒苔和马尾藻处的海表面温度比周围水体的海表面温度高1~2℃,浒苔和马尾藻爆发的适宜温度范围为23~26℃。     

南黄海浒苔漂移轨迹年际变化规律及驱动因素

综合利用环境卫星(HJ-1A/1B)CCD影像与MODIS影像,对2011-2017年南黄海海域浒苔信息进行了提取,并结合QuickSCAT海风数据以及ESRL海温数据对浒苔生长及漂移路径的影响进行了分析。结果表明:(1)7年中利用遥感手段最初发现浒苔的日期为5月份,初始发现位置多集中在江苏省盐城市附近海域,且近7年浒苔漂移方向整体上向北,进入山东半岛海域。其中,浒苔中心点距离青岛海域最远约115km(2015年6月21日),最近约9.6km(2012年7月11日)。(2)浒苔中心点漂移方位年际差异较大,整体上浒苔漂移路径方向与海面风风向高度一致。(3)SST是浒苔暴发的关键环境因子,南黄海海域5—8月份SST逐月升高为浒苔生消过程提供了环境条件。     

基于NDVI与丰度关系的MODIS影像浒苔混合像元分解方法

MODIS影像是浒苔业务化卫星遥感监测的重要数据源,但其空间分辨率(250m)较低,混合像元效应导致传统的NDVI(Normalized Difference Vegetation Index)阈值法浒苔提取误差较大。为解决此问题,本文以准同步的较高分辨率的HJ-1CCD影像浒苔提取结果为基准,建立基于MODIS NDVI与浒苔像元丰度(浒苔覆盖面积占像元面积百分比)关系的浒苔信息提取模型,利用该模型可提取每个像元的丰度(即浒苔覆盖率),从而提高整景影像浒苔覆盖面积提取精度。该模型可为浒苔灾害等级的确定以及防灾减灾应急决策提供支持。     

基于遥感反演的浒苔绿潮暴发对有色溶解有机物与叶绿素时空分布特征的影响

浒苔的暴发会对水体生态环境产生巨大的影响, 对此进行遥感监测具有十分重要的意义。本文基于现场同步实测的有色溶解有机物(colored dissolved organic matter, CDOM)吸收系数、叶绿素浓度以及光谱数据建立遥感反演模型,再结合MODIS卫星影像提取山东半岛南侧近岸海域在各年份浒苔暴发前后CDOM与叶绿素浓度的时空分布特征。结果表明, 浒苔的消亡分解会在水体中产生大量的CDOM, 但浒苔的生长繁殖同样会消耗CDOM, 此外CDOM还受到浒苔暴发时期强烈的光降解作用。在各种因素的综合作用下, 研究区海域CDOM浓度在浒苔暴发时期微弱升高, 浒苔消亡后CDOM浓度则开始回落。浒苔在暴发期会抑制其他浮游微藻的生长, 使研究区海域叶绿素浓度有所降低, 而浒苔消亡后叶绿素浓度有所上升。水体中的叶绿素受多种生物地球化学因素的影响, 因此叶绿素浓度的降低与浒苔的暴发强度之间没有明确的相关性。遥感反演可以大范围快速地提取水体中各种要素的分布情况, 但就浒苔的暴发对海水中各要素的影响机制而言, 还需要结合各种生态环境因子进行综合分析。     

2017年绿潮浒苔(Ulva prolifera)生理特征及孢子囊形成情况分析

近几年来在我国青岛海域连续暴发的浒苔绿潮造成了巨大的经济损失并且破坏了近海海洋生态系统平衡。因此,浒苔绿潮受到了越来越多的关注。本研究重点关注了绿潮暴发期间不同海域浒苔藻体生理特征和孢子囊形成情况。研究发现,不同海域里浒苔藻体生理特征差异显著,孢子囊比例显著不同,并且观察到漂浮浒苔的原位萌发。2017年5月中旬,我们在苏北浅滩紫菜养殖区域(33.78°N,121.29°E)对筏架绠绳上生长的绿藻,退潮后滩涂散落的绿藻和涨潮时海面上漂浮的绿藻进行为期5天的野外采集。另外,在2017年6月随科考船对浒苔暴发海域的浒苔样本进行采集。采集范围在(33.5°—36.5°N, 120°—124°E)。结果表明,从低纬度到高纬度,浒苔F_v/F_m(光系统Ⅱ最大光化学量子产量)值从0.65逐渐降低至0.3左右;YⅡ(光系统Ⅱ实时光化学量子产量)值也从最高0.5左右降低至最低0.1。此外,定生浒苔F_v/F_m值为0.6—0.8左右,明显高于漂浮浒苔; YⅡ值也有类似趋势。在孢子囊形成比例方面,定生浒苔约有5%藻体形成了孢子囊,而漂浮浒苔中孢子囊形成比例达到20%。数据表明,低纬度区域为浒苔来源地,浒苔生理活性良好,孢子囊形成比例低。随着浒苔往北漂移,其生理活性降低。并且,漂浮浒苔孢子囊形成比例显著性高于定生浒苔。本文认为,浒苔脱离来源区后,孢子囊的快速形成、成熟和孢子释放以及孢子的原位萌发是浒苔生物量激增的重要原因。     

青岛近海浒苔暴发期大型底栖动物群落的生态研究

利用2008年7月3日至25日在青岛附近海域浒苔[Enteromorpha prolifera (Muell.)J.Ag]暴发期间进行的大型底栖动物定量分析资料,研究了该海域大型底栖动物群落在物种组成、生物量和丰度以及物种多样性方面的动态变化,以了解浒苔暴发对大型底栖动物的生态学影响.结果表明,本项目调查共采集到大型底...     

不同氮磷比值下浒苔与石莼的竞争作用研究

近年来，海水富营养化导致近海海域大型海藻过量繁殖，成为世界性的环境问题。自2007年以来，浒苔绿潮在黄海海域连续暴发，造成巨大经济损失。为探究浒苔大规模暴发与氮磷比值(N/P)的关系，及其与其他大型绿藻在不同N/P下的竞争机制，研究了浒苔(Ulva prolifera)与石莼(Ulva lactuca)在不同N/P下单独培养和共培养时的生长情况，探究了浒苔及石莼生长的变化；结合苏北浅滩海域现场N/P的调查结果，分析了浒苔绿潮暴发的可能机制。研究结果表明:(1)浒苔单独培养时，在一定范围内高N/P能促进浒苔的生长，氮对于浒苔的影响大于磷。(2)石莼单独培养时，低N/P下石莼长势最好，但改变N/P对石莼的影响并不显著。(3)浒苔和石莼共培养时，浒苔生长受到了一定限制，低N/P下浒苔生长受限更显著。(4)苏北浅滩海域高N/P更适合浒苔的生长，可能是浒苔绿潮能够大规模暴发的原因之一。     

黄海浒苔漂移输运模式的建立与应用

本文利用NCEPGFS预报风场和中国近海高分辨率三维MASNUM海浪-潮流-环流耦合海洋数值预报系统的预报数据,建立黄海浒苔漂移输运模式,用于黄海浒苔溯源和漂移输运数值模拟研究。使用2009年5月份黄海表层漂流浮标数据和2012年MODIS卫星遥感浒苔漂移分布资料对所建立的漂移输运模式进行验证,结果表明所建立的模式能够有效的模拟出浒苔暴发区漂流浮标运动状况,并能够有效地模拟出2012年浒苔漂移输运过程。最后运用所建立的模式开展2008年和2010年浒苔漂移输运过程,模拟结果与文献报道的卫星观测结果一致。模拟结果表明,受海洋表层流影响两年浒苔特征显著不同:2010年浒苔影响海域明显小于2008年,且2010年浒苔主体没有大规模在青岛近岸堆积。     

青岛近海浒苔光谱特征研究

针对从2008年以来,每年夏季我国黄海南部暴发大面积的浒苔(Enteromorpha)灾害,对海洋环境及经济造成不利影响的状况,为了进一步研究浒苔特性,为利用遥感手段监测浒苔提供一定的理论依据,通过实地测量不同条件下浒苔的光谱反射率曲线,定性分析了浒苔的光谱特征。结果表明,浒苔的基本光谱特征表现为在蓝光波段和红光波段形成反射谷,在绿光波段形成反射峰,而在近红外波段反射率明显增大,形成高反射峰。因此将红光波段和近红外波段作为敏感波段,利用NDVI(归一化植被指数)提取遥感图像上的浒苔信息,可取得较好效果,有利于浒苔监测。     

浒苔绿潮消亡腐败过程中的营养盐释放及其对近海环境的影响

为探讨浒苔绿潮消亡腐败过程中的营养盐释放规律以及浒苔绿潮聚积腐烂对海水水质的影响，在室外模拟近岸浒苔绿潮聚积腐烂过程，并于2018年6月在浒苔绿潮靠岸前开始对主要浒苔绿潮聚积地(鳌山湾、鳌山湾口的海参池、石老人海域)进行观测，实时记录浒苔腐烂状况及对周边环境的影响。模拟实验结果表明:各形态氮、磷营养盐在浒苔腐烂分解过程中升高明显，且以溶解有机态、颗粒态为主。其中生物量为5 g/L实验组溶解有机氮(Dissolved Organic Nitrogen，DON)、颗粒态氮(Particulate Nitrogen，PN)、溶解有机磷(Dissolved Organic Phosphorus，DOP)、颗粒态磷(Particulate Phosphorus，PP)的浓度在浒苔腐烂分解过程中达本底浓度的5～10倍以上。现场调查结果显示，随着浒苔绿潮在青岛近岸聚积，各调查站点的溶解无机氮(Dissolved Inorganic Nitrogen，DIN)、DON、DOP受浒苔绿潮吸收影响均降至最低值，后随着浒苔绿潮腐烂逐渐上升，水质恶化。其中鳌山湾受浒苔绿潮腐烂影响最为严重，在调查期间水体甚至劣于二类水质。PN、PP为调查区内营养盐的主要赋存形式，其中鳌山湾海域PP变化最为明显，随着浒苔绿潮聚积腐烂达到最高值(2.02 μmol/L)。相比于鳌山湾，石老人海域海水交换能力强且在浒苔绿潮靠岸后进行了及时拦截打捞，受浒苔绿潮消亡腐烂影响较小。浒苔绿潮靠岸聚积腐烂，使海域内营养盐含量与结构明显变化，影响海域浮游植物群落结构的稳定,可能引发赤潮等次生生态灾害。因此需要及时清理聚积在青岛近岸的浒苔，避免其腐烂对周边环境造成影响。     

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。     

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.     

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.     

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,     

Estimation of Sediment Properties during Benthic Impact Experiments

Sediment properties, such as water content and density, have been used to estimate the dry and wet weights, as well as the volume of sediment recovered and discharged, during benthic impact experiments conducted in the Pacific and Indian Oceans. The estimates show that the weights of dry (355-1332 t) and wet sediment (1651-4888 t) recovered during the experiments, are not only a function of the total duration and distance covered during the experiment, but also depend on water content and density of the sediment. Estimation of dry sediment and its volumetric ratio in the discharge, are key parameters for calculating the discharged volume. The estimated volume of wet sediment recovered (1427-4049 m 3 ) as well as discharged (2693-6951 m 3 ) during the experiments, provide important inputs to evaluate the sediment resettlement and migration. Using these estimates, the average depth of excavation on the seafloor, can also been calculated. However, the stages of sediment recovery and discharge are expressed differently in some of the experiments. In order to standardize these, different stages have been identified, and definitions of certain terms have been suggested, for use in the future. The methods of calculating different properties, as well as weight and volume of discharged sediment are described in the paper for use in other applications concerning deep-sea discharges.