大鹏湾海水环境要素与夜光藻增殖的灰关联模型｛GM（1,n）｝

1　前　　言夜光藻(Ｎｏｃｔｉｌｕｃａｓｃｉｅｎｔｉｌｌａｎｓ)是我国海洋赤潮的主要发生藻。作者曾运用时间序列模型、回归分析及微分方程的变分模型和灰关联等对夜光藻种群增殖和形成赤潮的原因进行过分析和研究[1～5]。作者有关夜光藻种群动态时间序列模型研究[1],已确定了夜光藻种群3天内暴发性增殖的必要条件:在适宜生长的环境条件下,夜光藻种群细胞密度应大于10×106ｃｅｌｌ·ｍ-3。在海水环境要素对夜光藻种群密度增殖的影响的研究[5],认为温度、溶解氧、营养盐(可溶性氮盐和可溶性磷盐)与夜光藻增殖有明显的相关性,并确定了夜光…     

棘尾虫接合生殖的研究——Ⅰ.接合生殖中的核行动

纤毛虫属于单细胞动物,它们通常以二分裂法进行无性繁殖,但到一定时期和在一定条件下也要进行有性生殖。它们有性生殖的一种主要方式叫做接合生殖,这种有性生殖法不能形成真正的配子与合子,只能通过两个接合的亲体间进行生殖核的交换而形成合子核,因此不存在脱离亲体的独立的配子细胞,和由之而产生的与亲体可以并存的子代。     

大鹏湾夜光藻赤潮发生风险率的随机过程分析

本文以春季大鹏湾夜光藻种群等间隔采样序列作为随机过程变量,运用随机过程理论,构造了夜光藻种群超阈值风险的成丛随机点过程复合模型,对夜光藻赤潮风险率的随机过程进行分析,得到夜光藻赤潮的风险估算,并进行拟优合度检验.认为研究结果对预测夜光藻赤潮发生具有一定的指导意义.     

海藻有性繁殖生态学研究进展

由于研究技术与方法的不断改进 ,人们对海藻 (seaweeds)早期生活史方面的研究兴趣日益增大。评述了近年来海藻有性繁殖过程中配子释放和受精生态学问题。到达一定生理状态的海藻 ,通过对环境暗示应答而诱导配子形成。海藻生殖器官感受另一些特定的环境条件 ,通过有关信号传递机制 ,触发配子释放。海藻配子释放的时间及其所需的环境条件 ,依不同的种类而变化。配子同步释放以及各种适当的环境条件提高了受精频率和受精成功率 ,有利于受精的各种生物的和非生物的因素组合 ,形成了“机会窗 (the window of opportunity)”的概念。近年来的研究表明 ,海藻 (特别是红藻 )的自然受精成功率比以前所认为的要高得多。受精后合子 (胚 )的散布、集落与附着显著地影响其生存以及种群动态。对今后值得进一步研究的方面作了展望     

塔玛亚历山大藻和东海原甲藻对褶皱臂尾轮虫种群数量的影响

通过对2002年5月东海赤潮原因种一东海原甲藻和亚历山大藻的单一藻种和两种藻混合情况下对褶皱臂尾轮虫种群数量影响的实验研究,发现塔玛亚历山大藻(ATHK)对轮虫有致死作用,其48hLC50为1300cell·ml^-1．藻的各组分毒性比较研究表明,只有藻液和藻细胞具有这种毒害作用,藻在早期生长阶段的毒害作用较强,毒性大小与藻细胞活性相关．东海原甲藻在高密度(4×10^4、5×10^4、10×10^4cell·ml^-1)时对轮虫种群数量在第5d时开始有影响;东海原甲藻在低密度(1×10^4、2×10^4、3×10^4cell·ml^-1)时,轮虫能够以其为食并进行生长繁殖．两种藻混合情况下,东海原甲藻能够减轻塔玛亚历山大藻对轮虫的毒害作用．实验结果表明,此次赤潮对东海的微型浮游动物种群能够产生一定的影响．     

东海低氧区及邻近水域浮游植物的季节变化

根据2011年5月、8月、11月在东海低氧区及邻近水域(25°00'—33°30'N,120°00'—127°30'E)进行的多学科综合调查,对东海低氧区及邻近水域浮游植物群落结构特征及季节变化进行了相关研究。经Utermhl方法初步分析共鉴定出浮游植物4门74属248种(含变种、变型,不含未定种),主要由硅藻和甲藻组成,此外还有少量的金藻和蓝藻。春季优势种主要为具齿原甲藻(Prorocentrum dentatum)、柔弱伪菱形藻(Pseudo-nitzschia delicatissim)、骨条藻(Skeletonema sp.)和具槽帕拉藻(Paralia sulcata);夏季主要是中肋骨条藻(Skeletonema costatum)和海链藻(Thalassiosira sp.);秋季主要是具槽帕拉藻、圆筛藻(Coscinodiscus sp.)和柔弱伪菱形藻。调查区浮游植物平均细胞丰度在夏季最高,达到85.002×103个/L,春季次之,秋季最低。在水平方向上,春、夏两季,表层浮游植物细胞丰度在近岸出现高值,由近岸到外海细胞丰度逐渐降低;而在秋季则相反,在调查海域的东北部出现高值,随离岸距离的增加细胞丰度逐渐增加。在垂直方向上,春、夏两季,浮游植物细胞丰度在表层出现最大值,随着深度的增加细胞丰度逐渐降低;而在秋季细胞丰度分布比较均匀,随水深变化不明显。调查区表层浮游植物ShannonWiener多样性指数和Pielou均匀度指数的平面分布基本一致,并且与细胞丰度的分布大致呈镶嵌分布。调查浮游植物群落的演替规律是:从春季的甲藻(具齿原甲藻、微小原甲藻(Prorocentrum minimum)等)为主,硅藻(柔弱伪菱形藻、骨条藻等)为辅;演替至夏季的硅藻(中肋骨条藻、海链藻等)为主,甲藻(主要是梭状角藻(Ceratium fusus)和叉状角藻(Ceratium furca))为辅,到秋季进一步演替为硅藻(具槽帕拉藻、圆筛藻、柔弱伪菱形藻等)为主,铁氏束毛藻(Trichodesmium thiebaultii)为辅。浮游植物物种组成、优势种、细胞丰度及多样性指数均表现出明显的时空变化。低氧区与非低氧区浮游植物群集存在明显差异。     

南海大鹏湾甲藻孢囊分布研究

甲藻及其它赤潮生物孢囊被认为是赤潮发生的种源,其分布特征是赤潮发生预测的重要依据。本研究对南海大鹏湾赤潮发生密集海区底泥进行了采集分析。在调查的12个站位中,共发现甲藻抱囊29种,针抱藻抱囊1种,其中以锥状斯氏藻（ScriPPsiellatrochoidea）为最优势种,多边膝沟藻（GonyaulaxPolyedra）、褐色原多甲藻（ProtoPerdiniumavellana）和塔马亚历山大藻（Alexandriumtamarense）为优势种。抱囊的水平分布以水深最深的S2和水流最缓的S4两站位抱囊的种类、数量最为丰富,且两站位的营养盐含量高于其他站位。对抱囊的垂直分布的调查显示,大多数生活抱囊集中于NP和活性磷酸盐丰富的0-5cm底泥中,5cm以下抱囊数量骤减。根据样品中各类抱囊的比例与分布特征,对大鹏湾水域抱囊形成、沉降、水底运动和分布机制进行了推测。     

山东海域赤潮灾害特征及预警报管理

掌握赤潮灾害时空分布规律是科学设计赤潮监控方案、提高防灾管理效率的基础和依据。本文统计分析了1990—2010年间山东海域的76次赤潮灾害事件数据。结果表明:赤潮灾害频率显著地分为4个波段,且峰值呈递增趋势;灾害面积呈现周期性倒U型曲线变化;每年的5—10月是赤潮灾害的多发期,其中,8月的灾害次数和灾害面积均占全年总数的30%以上;灾害空间分布集中在莱州湾海域、青岛近海、庙岛群岛的北隍城海域,烟台四十里湾的赤潮灾害最频繁;夜光藻(Noctiluca scintillans)和球型棕囊藻(Phaeocystis globosa)引发的赤潮灾害面积最高,夜光藻和红色裸甲藻(Gymnodinium sanguineum)致灾次数最多。本文从赤潮监测与信息采集、赤潮预报方法以及赤潮灾害预警报管理机制3个方面分析总结了山东海域赤潮灾害预警报业务化管理现状,结合山东海域赤潮灾害特征和预警报管理实践,提出了以控制污染和修复生态环境为根本的赤潮防控建议。     

长江口及其邻近水域网采浮游植物群落

根据2006年2月～11月在长江口及其邻近水域的采样调查,对调查水域网采浮游植物群落结构特征进行了研究.共鉴定出浮游植物5门72属177种(包括未定名种),浮游植物以硅藻为主,但甲藻在群落中的比重也很明显,此外还有少量的绿藻、蓝藻和金藻.浮游植物优势物种以可形成链状群体的物种为主,中肋骨条藻(Skeletonema costatum)在长江口水域全年都具有较高的优势度,另外还有季节性的优势种,春季的夜光藻(Noctiluca scientillans)和具齿原甲藻(Prorocentrum dentatum),夏季的细长翼鼻状藻(Proboscia alata f. gracillima),秋、冬季的琼氏圆筛藻(Coscinodiscus jonesianus)和星脐圆筛藻(Coscinodiscus asteromphalus).浮游植物物种多为温带近岸种,少数为暖水种或大洋高盐种.长江口水域网采浮游植物的细胞平均丰度在夏季最高,为2027.41×104 cells m-3,其次为春季,秋季最低,为22.15×104 cells m-3.冬季的细胞丰度在各站之间变化幅度是最小的.浮游植物物种组成、细胞丰度及多样性指数在区域上和时间上都表现出明显的差异.调查所获4季度月网采浮游植物的丰度资料与历史资料基本吻合,季节变化也基本一致,但也有个别季度差别较大,长江径流量的年际变动可能是造成这种差别主要原因之一.     

东海原甲藻（Prorocentrum donghaiense）和链状亚历山大藻（Alexandrium catenella）对模拟食物链物质传递的影响

研究了东海原甲藻的基本营养组成,并就赤潮密度下的东海原甲藻（Prorocentrum donghaiense）和链状亚历山大藻（Alexandrium catenella）在单一和混合情况下对赤潮藻→卤虫模拟食物链物质传递的影响进行了探讨。结果表明：与其它饵料微藻相比,东海原甲藻必需氨基酸中的苯丙氨酸、赖氨酸和组氨酸含量明显偏低。东海原甲藻单独投喂时,卤虫对其的总物质转化效率随着藻密度的增加呈现先逐渐增加再逐渐降低的趋势。而当不同密度的东海原甲藻分别与一种硅藻小新月菱形藻(Nitzschia closterium)混合投喂时,随东海原甲藻密度的增加,卤虫选择性地增加对东海原甲藻的摄食,而降低对小新月菱形藻的摄食,并且其总物质转化效率逐渐降低。暴露于链状亚历山大藻藻液,卤虫体重减轻,且在其体内未检测到叶绿素a,表明卤虫未摄食该藻。当链状亚历山大藻藻细胞重悬液和去藻过滤液分别与小新月菱形藻或东海原甲藻混合时,卤虫对后两株藻的摄食量和总物质转化效率均有所降低。因此,在大规模赤潮发生时,东海原甲藻和链状亚历山大藻可能分别对浮游动物的营养和存活带来不利影响,并影响物质沿食物链的传递。     

Noctiluca scintillans may act as a vector of toxigenic microalgae

Noctiluca scintillans food vacuoles containing toxigenic microalgae of the genera Dinophysis and Pseudo-nitzschia are reported in samples from the Galician Rías Baixas (NW Spain). N. scintillans may play an important role in the population dynamics of toxigenic microalgae blooms, and may act as a vector of phycotoxins to higher trophic levels. The harmful effects of Noctiluca in natural shellfish beds and/or aquaculture sites may be magnified if cells are loaded with toxigenic microalgal prey.     

Zooplankton assemblages as indicators of seasonal changes in water masses in the boundary waters between the East China Sea and the Taiwan Strait

Hydrology and trophic relationships are frequently reported for inducing changes in mesozooplankton communities. This study investigated the distribution and abundance of mesozooplankton in the boundary waters between the East China Sea and the Taiwan Strait. Samples were collected using a NOR-PAC zooplankton net towed horizontally at a depth of 2 m, at eight stations along a transect, in March (spring) and October (autumn) 2005. The abundance of mesozooplankton was significantly higher during autumn than spring. Densities of many groups (e.g., Noctiluca scintillans, pteropods, copepods, mysids, euphausiids, and other larva) increased in October. During both seasons, copepods represented more than 50% of the total zooplankton abundance. Noctiluca scintillans, appendicularians, and Calanus sinicus were dominant in spring, indicating their association with the cold waters of the East China Coastal Current. Appendicularians and N. scintillans were mainly associated with the coastal waters of Taiwan; whereas C. sinicus was concentrated in the offshore waters along the coast of Mainland China. Chaetognaths, Temora turbinata, Acrocalanus spp., and radiolarians were dominant in autumn, showing their association with the warm waters of the Kuroshio Branch Current. Oncaea venusta was relatively abundant during both seasons. Our study shows that, in addition to the influence of seasonal changes in the water masses, the distribution and composition of mesozooplankton are highly influenced by trophic interactions between zooplankton taxa, in the boundary waters of the Taiwan Strait and the East China Sea.     

Real-Time Polymerase Chain Reaction Assays for Rapid Detection and Quantification of <Emphasis Type="Italic">Noctiluca scintillans</Emphasis> Zoospore

Application and availability of real-time polymerase chain reaction (PCR) assay to detect and quantify the Noctiluca scintillans zoospore were investigated seasonally. Specific primer set for N. scintillans 18S rDNA was designed and applied to real-time PCR assay using the serial dilutions of N. scintillans zoospores. The real-time PCR assays with Ns63F and Ns260R primers were applied to sea water samples collected weekly in Manazuru Port of Sagami Bay, Japan from April 2005 to June 2006. We developed effective DNA preparation steps for collecting the template DNA of N. scintillans zoospore: size fraction and filter concentration of the water samples, fixation with Lugol solution, cell lysis, and purification. This method is useful for the monitoring of the zoospores of N. scintillans, and can also be used for other small and physiologically fragile planktonic cell. Variation in the density of zoospore was successfully detected in the field samples. The peak density of N. scintillans zoospore was observed to occur just before or at the same time as the peak of the vegetative cells. Moreover, zoospores were detected in seawater even when the vegetative cells were not observed. The presence of zoospore was found all year round in the present study. In this regards, this information is essential for the study of the life cycle and seasonal variation of N. scintillans in the coastal waters.     

The Density of a Homogeneous Population of Cells Controls Resetting of the Program for Swarmer Formation in the Unicellular Marine MicroorganismNoctiluca scintillans

Noctiluca scintillansis a luminescent marine dinoflagellate. The life cycle ofNoctilucaconsists of a vegetative stage and a swarmer stage. The swarmer stage ofNoctilucais initiated by formation of a swarmer-mother cell instead of binary fission of vegetative cells. We studied the formation of swarmers under various conditions and became convinced that the cells have a strict program for the formation of swarmers which starts to operate in every cell after a defined number of cell cleavages. The probability that the program will be executed appeared to be affected by the presence of other cells. In other words, a high density of cells suppressed the expression of the program. Suppression was achieved by resetting the mechanism and was related to the number of cell divisions. Our findings provide one of the simplest examples of a mechanism by which a large population produces individuality in a group of genetically homogeneous organisms.     

The influence of upwelling,coastal currents and water temperature on the distribution of the red tide dinoflagellate, <Emphasis Type="Italic">Noctiluca scintillans</Emphasis>, along the east coast of Australia

Quasi-synoptic surveys along the east coast of Australia between 28 and 34°S show that the heterotrophic dinoflagellate, Noctiluca scintillans, occurs along this entire stretch of the coast. Areas of relatively high abundance of Noctiluca were observed downstream of regions predisposed to current-induced upwellings as a consequence of alongshore topographic variations. High-resolution temporal and spatial sampling of upwelling events showed that Noctiluca was abundant (up to 28 cells l^?1) within mature upwelled waters. A high proportion (>80%) of fed Noctiluca cells (cells with prey in their vacuoles) was observed in the mature upwelled waters indicating that the observed increase in abundance of Noctiluca was associated with increased feeding activity. The absolute abundance of Noctiluca in upwelled waters was, however, found to vary from one upwelling location to another and between seasons. In particular, highest abundances of Noctiluca were recorded south of 31.5°S, where the East Australian Current (EAC) characteristically separates from the coast. The high abundances partly arise from southward advection and retention of the Noctiluca cells, and partly from upwelling inshore of the separated EAC driven by cross-shelf boundary layer fluxes. The temperature of the EAC was also found to influence absolute abundances. Surface water temperatures during our summer cruise were anomalously high due to a strong La Niña phase, and up to 4°C warmer than during our spring cruise. We found that the warmer surface water temperatures were associated with relatively lower average abundances of Noctiluca in the near shore zone.     

Long-term changes in Noctiluca scintillans blooms along the Chinese coast from 1933 to 2020

Noctiluca scintillans is one of the most common harmful algal species and widely known due to its bioluminescence. In this study, the spatial distribution, seasonal variations, and long-term trends of N. scintillans blooms in China and the related drivers were analyzed and discussed. From 1933 to 2020, a total of 265 events of N. scintillans blooms were recorded in Chinese coastal waters, with a total duration of 1052 days. The first N. scintillans bloom occurred in Zhejiang in 1933, and only three events were recorded before 1980. From 1981 to 2020, N. scintillans caused harmful algal blooms (HABs) almost every year, both the average duration and the proportion of multiphase HABs showed an increasing trend. 1986–1992, 2002–2004, and 2009–2016 were the three peak periods with a frequency of no less than five events of N. scintillans blooms per year. In terms of spatial distribution, N. scintillans blooms spread from the Southeast China Sea to the Bohai Sea after 2000, Guangdong, Fujian, and Hebei were the three provinces with the highest numbers of recorded events of N. scintillans blooms. Moreover, 86.8% of the events of N. scintillans blooms occurred in spring (March, April, and May) and summer (June, July, and August). Among environmental factors, the dissolved inorganic phosphate, dissolved silicate and chemical oxygen demand were significantly correlated with the cell density of N. scintillans during N. scintillans blooms, and most of N. scintillans blooms were recorded in the temperature range of 18.0–25.0°C. Precipitation, hydrodynamics, water temperature, and food availability might be the main factors affecting the spatial–temporal distribution of N. scintillans blooms along the Chinese coast.     

New details from the complete life cycle of the red-tide dinoflagellate Noctiluca scintillans (Ehrenberg) McCartney

Noctilucid protozoans are among the dinoflagellates that cause red tides. Sexual reproduction may occur in this group, as they sometimes undergo gametogenesis. However, the life cycle, in particular the developmental process after gamete fusion, has not been fully elucidated. We have been able to maintain clonal cultures of Noctiluca scintillans throughout the whole life cycle and have revealed new details of various stages. In trophont populations, a small fraction of cells spontaneously transform into gametogenic cells, which undergo two successive nuclear divisions, without cellular division, probably corresponding to meiosis. The products of nuclear division migrate to the cell surface with a small amount of cytoplasm, and there further synchronously divide 6-8 times, during which the division products are connected by thin cytoplasmic bridges. Thus, numerous gametes with a semi-spindle body shape are released from the mother cell ghost. They retain two flagella that differ in length and motion, as is typical of dinoflagellates. The presence of longitudinal and transverse grooves indicates that dinoflagellate-like characteristics are conserved in the gametes, although they are not present in the specialized trophonts. Zygotes with four flagella result from the fusion of two isogametes. The zygotes change shape from spindle to spherical, with a reduction in flagellar number. The developing cell acquires a tentacle and crust, similar to large trophonts, and begins to develop a cytoplasmic network, thus completing the transformation into a miniscule trophont. These early trophonts grow to maturity as cell size increases. Our observations of the life cycle of N. scintillans may provide clues for understanding the evolutionary origin of noctilucae.     

POPULATION DYNAMICS OF GREEN NOCTILUCA SCINTILLANS (DINOPHYCEAE) ASSOCIATED WITH THE MONSOON CYCLE IN THE UPPER GULF OF THAILAND1

Population dynamics of Noctiluca scintillans (Macartney) Kof. et Swezy containing the photosynthetic endosymbiont Pedinomonas noctilucae (Subrahman.) Sweeney was investigated in relation to environmental conditions in the upper Gulf of Thailand. A clear association was observed between the abundance of N. scintillans and the monsoon cycle, with its blooms occurring during the southwest (SW) monsoon from May to September, and low abundance during the northeast (NE) monsoon from November to February. Nutrient concentrations were higher during the SW monsoon than during the NE monsoon due to the combined effect of increased river discharge into the northern upper gulf and the transport of the riverine inputs by the prevailing clockwise circulation of the water. These nutrient conditions favored the growth of both phytoplankton and the endosymbiont. Correlation analysis revealed that the higher abundance of N. scintillans in the SW monsoon was manifested primarily by higher growth through both sexual and asexual reproduction supported by phagotrophy. However, the dependence of N. scintillans on the nutrient concentration was not significant, probably because the nutrient supply for the endosymbiont was sufficient due to intracellular accumulation of nutrients within the host cells. Sexual reproduction occurred only during the SW monsoon, and its potential importance in population growth was suggested. These findings showed the bottom‐up control of the population dynamics of N. scintillans through growth of phytoplankton as prey. The seasonal shift in the circulation pattern associated with the monsoon cycle played a crucial role in blooming of N. scintillans by producing favorable food conditions.     

Nuclear 28S rDNA phylogeny supports the basal placement of Noctiluca scintillans (Dinophyceae; Noctilucales) in dinoflagellates

Noctiluca scintillans (Macartney) Kofoid et Swezy, 1921 is an unarmoured heterotrophic dinoflagellate with a global distribution, and has been considered as one of the ancestral taxa among dinoflagellates. Recently, 18S rDNA, actin, α-, β-tubulin, and Hsp90-based phylogenies have shown the basal position of the noctilucids. However, the relationships of dinoflagellates in the basal lineages are still controversial. Although the nuclear rDNA (e.g. 18S, ITS-5.8S, and 28S) contains much genetic information, DNA sequences of N. scintillans rDNA molecules were insufficiently characterized as yet. Here the author sequenced a long-range nuclear rDNA, spanning from the 18S to the D5 region of the 28S rDNA, of N. scintillans. The present N. scintillans had a nearly identical genotype (>99.0% similarity) compared to other Noctiluca sequences from different geographic origins. Nucleotide divergence in the partial 28S rDNA was significantly high (p<0.05) as compared to the 18S rDNA, demonstrating that the information from 28S rDNA is more variable. The 28S rDNA phylogeny of 17 selected dinoflagellates, two perkinsids, and two apicomplexans as outgroups showed that N. scintillans and Oxyrrhis marina formed a clade that diverged separately from core dinoflagellates.     

Occurrences of harmful algal blooms (HABs) associated with ocean environments in the South China Sea

Harmful algal blooms (HABs) occur frequently in the South China Sea (SCS), causing enormous economic losses in aquaculture. We analyzed historical HAB records during the period from 1980 to 2003 in SCS. We found that HABs-affected areas have expanded and the frequency of HABs varied during this period. The seasonal and annual variations, as well as causative algal species of HABs are different among the four regions. Areas with frequent HABs include the Pearl River Estuary (China), the Manila Bay (the Philippines), the Masinloc Bay (the Philippines), and the western coast of Sabah (Malaysia). HABs occurred frequently during March–May in the northern region of SCS, May–July in the eastern region, July in the western region, and year-round in the southern region. Among the species that cause HABs, Noctiluca scintillans dominated in the northern region, and Pyrodinium bahamense in the southern and eastern regions. Causative species also varied in different years for the entire SCS. Both P. bahamense and N. scintillans were the dominant species during 1980–2003. Some species not previously recorded formed blooms during 1991–2003, including Phaeocystis globosa, Scrippsiella trochoidea, Heterosigma akashiwo, and Mesodinium rubrum. Variations in HABs are related to various regional conditions, such as a reversed monsoon wind in the entire SCS, river discharges in the northern area, upwelling in Vietnam coastal waters during southwest winds and near Malaysia coastal waters during northeast winds, and eutrophication from coastal aquaculture in the Pearl River estuary, Manila Bay, and Masinloc Bay. Handling editor: D. Hamilton