The species pattern of Baltic phytoplankton in autumn 1991

Species pattern of phytoplankton in the surface waters (0–1 m) of the Baltic Sea was studied in the autumn 1991 during 25th cruise of the R/V “Akademik Mstislav Keldysh”. The samples were analysed by light and scanning electron microscopy. Results of this work show that sharp changes in the Central Baltic phytoplankton community have not yet begun. In coastal eutrophicated waters the growth of biomass and decrease of phytoplankton diversity are more significant.     

南海两个代表性海区藻华事件特征的比较研究

定量海洋浮游植物藻华事件的特征有利于认识海洋生态环境及动力过程,但由于遥感数据易受云层遮蔽的影响,以往对于南海藻华事件的研究多采用不连续的观测数据和遥感数据进行,因此未能系统性地认识南海中的藻华事件发生特征和控制规律。本文借鉴海洋热浪事件的统计分析框架,基于前期研究中构建的2005−2019年逐日、无缺失的遥感叶绿素a浓度资料,提取冬季吕宋西北部海域和夏季越南东南部海域两个代表性海区的藻华事件,分析两个代表性海区中藻华事件的持续时间、强度和长期趋势等特征。结果显示,吕宋西北部海域藻华频率降低,强度增大,且大部分海区趋势显著;越南东南部海域大部分海域趋势不显著。进一步分析两个海区藻华事件的影响因子,发现海面风场（正相关）和海表温度（负相关）对藻华事件影响最大;两个代表性海区藻华事件主要都由上升流控制,风是最重要的影响因子。分析藻华事件的先兆条件,发现温度锋面代表的亚中尺度活动也是一个重要的影响因子。本研究以南海为典型案例,为探讨海洋生态环境提供了新的研究视角。     

Interactions between a cyanobacterial bloom （Microcystis） and the submerged aquatic plant Ceratophyllum oryzetorum Kom

In aquatic ecosystems, macrophytes and phytoplankton are main primary producers, in which macrophyte plays an important role in maintaining clear water state, while phytoplankton often dominates in turbid waterbodies. In the present study, the growth and photosynthetic activity of the submerged aquatic plant Ceratophyllum oryzetorum Kom. in different cell densities of cyanobacterial bloom are studied. The results show that the plant length and fresh mass of C. oryzetorum are promoted by low cyanobacterial cell densities. Medium and high cyanobacterial cell densities, on the contrary, act as inhibitory. Furthermore, the photosynthetic activity of C. oryzetorum is strongly inhibited by high cyanobacterial cell densities. To a certain extent, the growth of cyanobacteria is inhibited by C. oryzetorum, but no significant effect is found in this study.     

太湖蓝藻水华遥感监测方法

利用遥感技术监测太湖蓝藻水华具有重要的现实意义.基于不同遥感数据,包括MODIS/Terra、CBERS-2 CCD、ETM和IRS.P6 LISS3,结合蓝藻水华光谱特征,采用单波段、波段差值、波段比值等方法,提取不同历史时期太湖蓝藻水华.结果表明:MODIS/Terra数据可以利用判别式Band2＞0.1和Band2/Band4＞1提取蓝藻水华;CBERS-2 CCD、ETM和IRS-P6 LISS3数据可以利用Band4大于一定阈值和Band4/Band3＞1提取蓝藻水华;波段比值(近红外,红光＞1)算法稳定,可以发展成为蓝藻水华遥感提取普适模式.同时,本文成功利用ETM和IRS.P6 LISS3数据Band4波段对蓝藻水华空间分布强度进行了五级划分.这为今后利用遥感技术,建立太湖蓝藻水华监测和预警系统莫定了基础.     

Planktonic and benthic microalgal community composition as indicators of terrestrial influence on a fringing reef in Ishigaki Island, Southwest Japan

Microalgal-based indicators were used to assess terrestrial influence on Shiraho coral reef of Ishigaki Island (Okinawa, Japan). A typhoon occurred on 4-5 August 2005 and sampling were made on three occasions thereafter (6, 8, and 11 August). Pre-typhoon sampling was conducted on 26 July. The typhoon-enhanced terrestrial discharges increased reef nutrient levels (e.g. average NO(3)(-)-N: 0.088mg/L pre-typhoon to 0.817mg/L post-typhoon). This elevated chlorophyll-a concentrations by four times and shifted phytoplankton composition (spectral class-based) from an initial dominance of diatoms and green microalgae to the dominance of bluegreen microalgae (cyanobacteria) and cryptophytes. Cyanobacteria later increased by more than 200% and accounted for as much as 80% of total chl-a ( approximately 0.29microg/L), possibly assisted by favorable nutrient availability. In outer reef waters, diatoms and green microalgae predominated whereas cyanobacteria and cryptophytes were nearly undetectable. Due to detrital decomposition and river discharge, the CDOM was much higher in the inner reef than in the outer reef. Benthic bluegreen microalgae were relatively more abundant in areas close to the river mouth and coastal agricultural fields. At these locations, nutrient concentrations were much higher due to river discharge and potentially significant groundwater discharge. Thus, phytoplankton and benthic microalgae can serve as indicators of terrestrial influence on coral reefs.     

苏北骆马湖浮游植物群落结构及其水质生物评价

为了解骆马湖浮游植物的群落结构及其水质健康状态,于2014年对骆马湖浮游植物进行逐月野外调查研究.共鉴定出浮游植物7门71种属,其中蓝藻门和硅藻门最多,其次为绿藻门.全湖细胞丰度在1.52×10~6~7.89×10~6 cells/L之间,全湖生物量在0.048~12.44 mg/L之间.非多维度量尺度分析结果显示,骆马湖全湖浮游植物生物量从冬春季喜低温的硅藻门为主演替到夏秋季喜高温的蓝藻门为主,表明骆马湖浮游植物有着明显的季节演替规律.与20世纪相比,骆马湖浮游植物优势种属有着很大的变化,富营养化指示属隐藻、纤维藻、针杆藻、鱼腥藻、伪鱼腥藻等明显增多,表明自20世纪以来,骆马湖富营养化程度正在加剧.与邻近的洪泽湖、南四湖、高邮湖、邵伯湖和宝应湖相比,骆马湖浮游植物细胞丰度高于宝应湖,但低于其他4个湖泊.基于浮游植物的水质评价结果,骆马湖目前处于从寡污带向β-中污带过渡的状态,富营养化程度轻于洪泽湖,与南四湖部分湖区富营养化程度相似.     

南极长城湾浮游植物生态的初步研究

本文利用 1 988年 3月至 1 989年 2月南极长城湾采集的浮游植物样品 ,作鉴定并定量分析。结果表明浮游植物种类组成显示出冷水性和近岸广温性种类为主的生态特点 ;优势种随季节变化而出现演替 ,其细胞数量变化呈夏季高峰的单峰型变化周期 ,各月细胞数量变化取决于该月优势种的演替。浮游植物的分布受诸多环境因子制约 ,日照时数是主导因子     

硝态氮对库区水体藻类和细菌群落的影响

水体富营养化极易引起湖泊水库如藻类水华等水生态系统环境问题。氮素作为初级生产力的限制性生源要素之一,认识其在水华形成过程中潜在作用至关重要。本研究选取胶东半岛低碳高氮水库水体进行模拟实验,通过添加不同剂量硝态氮,探究高硝态氮输入对库区水体藻类和细菌群落结构的影响。结果表明:(1)当硝态氮作为唯一氮源,随着培养时间延长,硝态氮浓度显著下降,亚硝态氮和氨氮浓度逐渐升高,表明微藻和细菌共同作用可能将硝态氮转化为亚硝态氮和氨氮;(2)当硝态氮浓度为6 mg/L时,藻类叶绿素a浓度达到最高值,随着硝态氮浓度升高,叶绿素a浓度则会降低;(3)添加硝态氮后,蓝藻门成为优势藻类,绿藻门次之;变形菌门相对丰度显著升高。研究结果为低碳高氮类水体暴发蓝绿藻水华及有效防控提供理论依据和技术支撑。     

胶州湾口内初级生产力的周年定点观测

于１９８３年１１月－１９８５年１１月利用黑白瓶测氧法研究了胶州湾东南部的初级生产力及其与各环境因子的关系。结果表明，调查区内初级生产力的变化范围是０．１０－２．８２ｇ／（ｍ＾２．ｄ）碳，年初级生产量的平均是２０６ｇ／ｍ＾２碳，夏半年（５－１０月）的初级生产量平均占全年生产量的７３．４５％，浮游植物的光合作用对有效太阳辐射能的平均利用率是０．６４％，初级生产力与水温，日太阳辐射能等均呈明显的正相磁，     

The Role of Dissolved Organic Carbon in a Shallow Lowland Reservoir Ecosystem — A Long‐term Study

Long‐term studies were conducted on the polymictic Siemianówka reservoir (SR), situated in a seminatural forest‐peat catchment in NE Poland. The studies were started on the second year of the reservoir's existence. The records showed dissolved organic carbon (DOC) concentrations gradually increasing up to 25…30 mg/L. The largest DOC pool in the reservoir comes from the spring load input, supplemented by the excessive development of phytoplankton with cyanobacteria dominance. The DOC limited the range of the photic zone, eliminated the occurrence of aquatic plants, and was a significant carrier of nutrients, which were gradually released to water, bringing about the “humoeutrophication” of the reservoir.