Chemical and Biological Studies of Particulate Organic Matter in the Ocean

This paper presents a review of the past decade's highlights of research on the isolation and characterisation of particulate organic matter (POM) in the world's oceans. The emphasis is on chemical studies but, in keeping with the growing interdisciplinary nature of marine science, advances in other disciplines are also discussed, particularly those in biological sciences. Increasing evidence for the importance of picoplankton, bacteria and viruses as POM constituents is highlighted, including the recent recognition of large populations of autotrophic bacteria able to harvest light for energy. The transport of POM to bottom waters was thought to be largely confined to large, rapidly sinking faecal pellets. However, recent studies have highlighted the importance of organic aggregates and flocs formed by diatoms such as Rhizosolenia and other microalgae. Ascending particles have also been discovered, many of which are lipid-rich. Several studies have shown that resuspension of bottom sediments and lateral advection of material from continental shelves can lead to anomalously high particle fluxes measured in sediment traps moored in deep water. Many new approaches for characterizing POM have emerged, such as pyrolysis gas chromatography-mass spectrometry and direct temperature-resolved mass spectrometry for analysis of higher molecular weight materials and biopolymers. Lipid biomarker techniques have also advanced, exciting new possibilities being raised by the ability to measure stable and radioactive carbon isotopes for individual compounds. The techniques of molecular biology, such as the polymerase chain reaction (PCR), are being increasingly applied to provide complementary information to more conventional microscopy and flow cytometry on the identity of organisms in the sea. The combination of these techniques with advanced chemical analysis methods promises to greatly increase our knowledge of the origins, transport and fate of organic matter in the oceans. This revised version was published online in August 2006 with corrections to the Cover Date.     

杭州湾锋区浮游植物现存量和初级生产力

１９８７年１２月和１９８８年７月，对杭州湾锋区附近海域的浮游植物细胞丰度、优势种类、叶绿素ａ浓度和初级生产力进行了现场测定。结果表明，夏季海域浮游植物细胞丰度（１９．９５×１０６个／ｍ３）高于冬季（５．６０×１０６个／ｍ３）。主要为广温低盐河口性类群和近岸广温广盐性类群占优势。夏季表层平均叶绿素ａ浓度为２．７４ｍｇ／ｍ３，冬季为１．２７ｍｇ／ｍ３。其平面分布特征表现为，表层浓度高于中层和底层，小潮汛的浓度高于大潮汛，落潮时的浓度高于涨潮时，跟踪测站的浓度高于Ｅ断面。夏季平均初级生产力为１５０．２７ｍｇＣ／（ｍ２·ｄ）。杭州湾为高悬浮物浓度的海域，光强成为初级生产力的主要限制因素之一。     

Ecological features of phytoplankton in red tide outburst area in the Xiamen Harbor

ＥｃｏｌｏｇｉｃａｌｆｅａｔｕｒｅｓｏｆｐｈｙｔｏｐｌａｎｋｔｏｎｉｎｒｅｄｔｉｄｅｏｕｔｂｕｒｓｔａｒｅａｉｎｔｈｅＸｉａｍｅｎＨａｒｂｏｒ￥ＺｈａｎｇＳｈｕｉｊｉｎ（ＲｅｃｅｉｖｅｄＪｕｎｅ２０，１９９４；ａｃｃｅｐｔｅｄＳｅｐｔｅｍｂｅｒ２，１...     

Seasonal Variations of Nutrients, Seston and Phytoplankton, and Upwelling Intensity off La Coruña (NW Spain)

This study describes the main seasonal stages in oceanographic conditions and phytoplankton off La Coruña (Galicia, NW Spain), during 1991 and 1992, based mainly on monthly cruises near the coast. Upwelling conditions were studied using an upwelling index calculated from local winds. The Galician coast is affected by a long upwelling season for most of the year. The upwelling pulses interact with the thermal stratification-mixing cycle of surface waters, primarily affecting the dynamics of phytoplankton. In addition, the presence of water masses of different salinity in the subsurface layers changes the stratification of the water column. The less-saline North Atlantic Central Water (NACW) was normally associated with upwelling events during summer. However, on several occasions during the study, the presence of Eastern North Atlantic Water (ENAW) of subtropical origin was observed with salinities up to 36·22 and temperatures between 13 and 14 °C.Observations were grouped into five main stages related to the degree of surface stratification and characteristics of phytoplankton communities. These stages were recognized in both annual cycles, and were termed: winter mixing, spring and autumn blooms, summer upwelling, thermal stratification and special events (red tides and downwelling). A homogeneous water column was the main characteristic of the winter stage, with high nutrient concentrations and low phytoplankton biomass. Eastern North Atlantic Water appeared at the end of this stage, which lasted from November to February. The spring and autumn blooms occurred along with weak thermohaline gradients at the surface, producing high phytoplankton concentrations. Favourable upwelling conditions and the presence of ENAW in a subsurface layer were the factors that most likely induced earlier blooms, while thermal gradients developed at the surface could have been more important for later blooms. Upwelling events during summer were related to a reduction in the depth of the surface mixed layer as the pycnocline moved upwards, and can produce significant phytoplankton accumulations. These summer blooms interrupted the thermal stratification stage, characterized by low nutrient and phytoplankton concentrations at the surface. The dominant phytoplankton in the study was composed mainly of diatoms, especially during blooms. However, a proliferation of red-tide dinoflagellates was observed along with weak upwelling conditions in late summer. Also in late summer, strong downwelling conditions caused the accumulation of warmer shelf waters inshore, inducing the sinking of particulate matter produced at the surface.     

厦门马銮湾外来物种沙筛贝对浮游植物的影响

分析了厦门马銮湾外来物种沙筛贝Mgtilopsis sallei入侵5年(1992—1996年)的3次海洋生态学调查资料,并整合近年来的有关资料作综合分析。结果表明,沙筛贝对浮游植物数量时空分布及该湾生态系产生了较大影响:沙筛贝入侵前,由于该湾富营养化逐年加重,浮游植物的丰度达到发生赤潮的数量级(1 000.0个.m-3),第Ⅰ、Ⅱ次网采样品密度分别为21 386×104和110 138×104个.m-3,增幅达5倍,浮游植物的优势种以耐污种优美伪菱形藻Pseuo-Nitzschi a delicatissima占绝对优势,群落的多样性指数下降到富营养化的阈值水平(H=1.0);但自1995年外来物种沙筛贝大量繁殖后,浮游植物的丰度稳定在同一数量级,第Ⅱ、Ⅲ次水采样品密度分别为1150.7和1 300个.cm-3,浮游植物的群落结构也发生了变异,厦门海区常见种尖刺伪菱形藻Pseuo-Nitzschiapungens和中肋骨条藻Skeletonema costatum被取而代之,群落的多样性指数上升到1.29。     

Spring phytoplankton bloom in the fronts of the East China Sea

Frontal areas between warm and saline waters of the Kuroshio currents and colder and diluted waters of the East China Sea (ECS) influenced by the Changjiang River were identified from the satellite thermal imagery and hydrological data obtained from the Coastal Ocean Process Experiment (COPEX) cruise during the period between March 1^st and 10^th, 1997. High chlorophyll concentrations appeared in the fronts of the East China Seas with the highest chlorophyll-a concentration in the southwestern area of Jeju Island (~2.9 mg/m³) and the eastern area of the Changjiang River Mouth (~2.8 mg/m³). Vertical structures of temperature, salinity and density were similar, showing the fronts between ECS and Kuroshio waters. The water column was well mixed in the shelf waters and was stratified around the fronts. It is inferred that the optimal condition for light utilization and nutrients induced both from the coastal and deep waters enhances the high phytoplankton productivity in the fronts of the ECS. In addition, the high chlorophyll-a in the fronts seems to have been associated with the water column stability as well.     

长湖浮游植物功能群特征及其与环境因子的关系

为查明长湖浮游植物功能群特征及其与环境因子的关系,于2015年4月至2016年1月开展了四个季度的调查分析,并运用冗余分析法(redundancy analysis,RDA)分析了浮游植物优势功能群与环境因子的关系。结果显示:本次调查共鉴定出26个浮游植物功能群,其中富营养化水体代表性功能群13个,优势功能群16个,其中功能群B、D、J、Lo、MP、W_1和X_1 (表1)为四季共有优势功能群。优势功能群的丰度和生物量均为夏季最高,春季其次。以最大相对丰度超过50%为评价指标,优势功能群的季节演替规律为X_1/X_2/B (春)→X_1(夏)→MP/X_1/B(秋)→D/X_1(冬),其中典型浅水富营养化水体代表功能群X_1的最大相对丰度和出现率均较高。冗余分析(RDA)表明,富营养化水体代表性功能群F、K、Lo、Lr、W_1和X_2在不同季节与总氮(TN)、磷酸盐(PO_4~(3-)-P)、溶解氧(DO)以及水温(WT)表现出不同程度的正相关性,水温(WT)和透明度(WD)是春季的主要环境限制因子,冬季X_1、D和J这三个优势功能群与各环境因子的相关性都很低。本次研究表明长湖整体处于中度富营养-富营养化状态,局部水域达到重度富营养化,这与运用其他指示生物对长湖的水质评价结果基本一致。     

递增负荷运动时的心电频谱研究

对20名受试者进行动态心电频谱研究。结果表明:1.递增负荷运动时,未疲劳心肌的心电积分(IECG)、平均功率频率(MPF)和均方根振幅(RMS)与运动负荷、射血加速度、射血前期线性相关。随着运动负荷的增加,心电频谱发生“右移”,并出现“频率集中”现象。指出心电频谱指标能在一定程度上反映心肌的收缩性.可作为运动时评价心脏负荷的指标。2.优秀运动员的IECG、RMS及其相对值与无训练者有显著性差异。同级负荷工作时,相对值IECG/HR、RMS/HR可同时反映心率和每搏心缩强度的比例,指出该指标可作为评价训练程度的参考指标。同时还分析了心电频谱变化的原因,提出“心肌分级收缩形式”和“心肌收缩功能态”的概念。     

胶州湾浮游植物分子遗传多样性初步研究

用聚合酶链式反应扩增海洋浮游植物总体的核酮糖 1 ,5 -二磷酸羧化 /氧化酶大亚基基因(rbc L)片段 ,建立该基因变异类型文库 ,并随机测定了 38个 rbc L大亚基基因片段序列 ,初步分析了海洋浮游植物分子遗传多样性。将≥ 97%的氨基酸序列相似性定义为种内变异 ,38个片段分别代表1 3个不同的物种 ,或称为不同的操作分类单元。与数据库序列比较发现 ,PPJZ0 1 ,PPJZ1 1和 PPJZ2 0可能是已报道的 rbc L基因序列代表的物种 ,其它克隆在数据库中没有对应的近缘物种序列存在。系统学分析表明分离的克隆分别属于隐藻门、硅藻门、绿藻门和 streptophyta等的浮游植物 ,极少数克隆来源于异鞭毛藻类、定鞭藻纲和原细菌。根据各操作分类单元克隆数计算得胶州湾浮游植物分子遗传多样性指数为 1 .97。研究结果为利用分子生物学方法剖分海洋浮游植物群落结构、研究海洋浮游植物动力学积累了基础数据