Structure and Production Potential of Summer Phytoplankton of Lake Baikal in the Present Period

Water Resources - A study of the structure and production parameters of phytoplankton (biomass, photosynthesis rate, chlorophyll a content, and assimilation numbers) in the coastal and pelagic...     

淮河流域春季浮游植物群落结构特征及其水质评价

浮游植物是内陆水体生态系统的主要初级生产者,其群落结构能反映水体的水质状况.为了全面了解淮河流域内浮游植物群落结构及水质现状,于2013年5月在流域内设置217个样点采集浮游植物样品.共鉴定浮游植物244种(含变种和变型),隶属于8门104属,绿藻门和硅藻门的种类最丰富.浮游植物生物量为3.93 mg/L,在0.04~83.62 mg/L之间变动,生物量组成主要为甲藻门、硅藻门和隐藻门.浮游植物种类数和生物量在河流的中游较高,溪流以及下游入江入海河道较低.浮游植物优势种主要为隐藻门的啮蚀隐藻(Cryptomonas erosa)、尖尾蓝隐藻(Chroomonas acuta),硅藻门的梅尼小环藻(Cyclotella meneghiniana),甲藻门的角甲藻(Ceratium hirundinella),其相对生物量均大于5%.淮河流域浮游植物多样性指数较低,流域内多数样点处于中-重污染状态.     

云贵高原湖泊夏季浮游植物组成及多样性

浮游植物是水生生态系统中重要的初级生产者,对维持水生态系统的平衡起着十分重要的作用.根据2008年云贵高原湖泊丰水期浮游植物调查数据,系统地分析了云贵高原13个湖泊中浮游植物的种群密度、生物量、组成及其多样性.云贵高原13个湖泊中共鉴定出浮游植物7门109种(绿藻52种、蓝藻23种、硅藻20种、其他14种).13个湖泊浮游植物Shannon-Wiener指数在0.5-2.2之间,其值大小与单个环境因子无显著相关.相关分析发现浮游植物总量与总氮、总磷、CODMn、硝态氮含量显著正相关,物种丰富度与总氮、总磷(0.1mg/L范围内)、CODMn含量亦显著正相关.另外,研究也发现各湖泊间浮游植物组成的相似性与各湖泊间营养状态差异显著负相关.由此可见,湖泊的营养状态不仅影响浮游植物的总量、组成以及物种丰富度,而且也影响各湖泊物种组成的相似性.     

Phytoplankton and periphyton production and its relation to temperature in a humic lagoon

To analyse the existence of interactive competition between phytoplankton and periphyton, we studied their photosynthesis–irradiance (P–E) response during one year in a humic lagoon. Lake production was dominated by phytoplankton, which followed seasonal changes in temperature. Periphyton primary production and algae biomass increased in winter, when phytoplankton biomass and production were lower. In this study we show that even in conditions of phytoplankton dominance, the habitat coupling between phytoplankton and periphyton can still be noticed.     

西太湖北部夏季藻类种间关系的初步研究

利用１９９１年至１９９７年对太湖梅梁湾的定点监测资料和１９９７年８月对西太湖北部的三次水化学和藻类布点监测资料,初步探讨了西太湖北部夏季藻类分布和种间关系。结果显示,西太湖北部夏季藻类主要由蓝藻,隐藻,硅藻,绿藻,裸藻和甲藻六大门类组成,以微囊藻为优势种的蓝藻水化主要在夏秋季暴发,夏季梅梁湾内藻类光合效率较高是该地区蓝藻暴发的原因之一;自梅梁湾河口湖我向外太湖,藻类总生物量递减,且种类组成也发生变     

Phytoplankton Kinetics in the Chesapeake Bay Eutrophication Model

The CE-Qual-ICM model computes phytoplankton biomass and production as a function of temperature, light, and nutrients. Biomass is computed as carbon while inorganic nitrogen, phosphorus, and silica are considered as nutrients. Model formulations for production, metabolism, predation, nutrient limitation, and light limitation are detailed. Methods of parameter determination and parameter values are presented. Results of model application to a ten-year period in Chesapeake Bay indicate the model provides reasonable representations of observed biomass, nutrient concentrations, and limiting factors. Computed primary production agrees with observed under light-limited conditions. Under strongly nutrient-limited conditions, computed product is less than observed. The production characteristics of the model are similar to behavior reported for several similar models. Process omitted from the model that may account for production shortfalls include variable algal stoichiometry, use of urea as nutrient, and vertical migration by phytoplankton.     

Phytoplankton biomass size structure and its regulation in the Southern Yellow Sea (China): Seasonal variability

Phytoplankton size structure plays a significant role in controlling the carbon flux of marine pelagic ecosystems. The mesoscale distribution and seasonal variation of total and size-fractionated phytoplankton biomass in surface waters, as measured by chlorophyll a (Chl a), was studied in the Southern Yellow Sea using data from four cruises during 2006–2007. The distribution of Chl a showed a high degree of spatial and temporal variation in the study area. Chl a concentrations were relatively high in the summer and autumn, with a mean of 1.42 and 1.27 mg m⁻³, respectively. Conversely, in the winter and spring, the average Chl a levels were only 0.98 and 0.99 mg m⁻³. Total Chl a showed a clear decreasing gradient from coastal areas to the open sea in the summer, autumn and winter cruises. Patches of high Chl a were observed in the central part of the Southern Yellow Sea in the spring due to the onset of the phytoplankton bloom. The eutrophic coastal waters contributed at least 68% of the total phytoplankton biomass in the surface layer. Picophytoplankton showed a consistent and absolute dominance in the central region of the Southern Yellow Sea (>40%) in all of the cruises, while the proportion of microphytoplankton was the highest in coastal waters. The relative proportions of pico- and nanophytoplankton decreased with total biomass, whereas the proportion of the micro-fraction increased with total biomass. Relationships between phytoplankton biomass and environmental factors were also analysed. The results showed that the onset of the spring bloom was highly dependent on water column stability. Phytoplankton growth was limited by nutrient availability in the summer due to the strong thermocline. The combined effects of P-limitation and vertical mixing in the autumn restrained the further increase of phytoplankton biomass in the surface layer. The low phytoplankton biomass in winter was caused by vertical dispersion due to intense mixing. Compared with the availability of nutrients, temperature did not seem to cause direct effects on phytoplankton biomass and its size structure. Although interactions of many different environmental factors affected phytoplankton distributions, hydrodynamic conditions seemed to be the dominant factor. Phytoplankton size structure was determined mainly by the size-differential capacity in acquiring resource. Short time scale events, such as the spring bloom and the extension of Yangtze River plume, can have substantial influences, both on the total Chl a concentration and on the size structure of the phytoplankton.     

九寨沟国家级自然保护区长海夏季浮游植物群落结构及生态评价

高山湖泊对于全球气候变化及人类影响是一个极为敏感的参照系统.九寨沟国家级自然保护区长海作为一个独特的高山湖泊,研究其浮游植物群落结构及其与环境的关系,评估其水质现状及影响因素,有着重要的意义.本文于2014年7月对长海浮游植物群落结构进行了研究.全湖共布设12个采样点,并在中心采样点进行了垂直分层采样.本次调查共发现浮游植物6门38属63种,平均丰度为6.98×10~5cells/L,平均生物量为0.31 mg/L.浮游植物的水平分布差异不大;在垂直分布上,浮游植物的丰度从表层0.5 m至水下50 m呈现先增加后减少的趋势,在20 m水深处达到最大.长海浮游植物的优势种是长海小环藻(Cyclotella changhai)和飞燕角甲藻(Ceratium hirundinella),长海小环藻数量较多,飞燕角甲藻生物量较大.长海浮游植物多样性指数较低,综合各类水质评价方法,可以得出九寨沟长海处于贫-中营养状态.     

Phytoplankton response to short-term temperature and nutrient changes

Meteorological extreme events (heavy rainfall, heat waves) may lead to fast changes in nutrient load and water temperature in temperate lakes. We conducted laboratory experiments with an artificial phytoplankton community to mimic a rapid temperature increase (from 21 °C to 29 °C) at low nutrient levels (‘heat wave scenario’), respectively temperature decrease (from 21 °C to 16 °C) and increased nutrient load (‘heavy rainfall scenario’). We hypothesised that there is a taxon specific nutrient x temperature interaction, leading to significant shifts in the phytoplankton community composition when both variables change. To separate the temperature effect from the nutrient effect, we performed another experimental series at a reduced temperature but without addition of nutrients. As expected, the nutrient effect was overall more important than temperature and significantly affected all five taxa tested that represented different algal classes. However, temperature also played an important role for community composition, because the cryptophyte Cryptomonas sp. and the dinoflagellate Peridinium sp. reached significantly higher biovolumes at lower temperatures. The nutrient x temperature interaction was significant in the green alga Scenedesmus obliquus. These findings suggest that our experimental results cannot be interpreted primarily by species competition for nutrients. Heterotrophic bacteria were present in all experiments. Bacterial biomass was significantly positively related to temperature and nutrients. However, relative to phytoplankton biovolume, bacterial biovolume decreased under nutrient replete conditions. In conclusion, our results demonstrate that short-term environmental change may significantly affect both the phytoplankton community (in terms of species dominance and total biomass) and the ratio between autotrophs and heterotrophs in temperate lakes.     

三峡库区浮游植物群落结构特征及水生态评价

2020年是长江禁渔开局之年,三峡库区作为长江的重要生态屏障,其水生态环境健康对长江大保护的实施具有重要意义。本文于2020年8月、11月及2021年1月、4月在三峡库区干支流共设置19个断面探究浮游植物群落结构特征,并利用生物量、多样性指数、综合营养状态指数和浮游植物Q指数等多种评价方法评价三峡库区水生态健康并分析其影响因素。结果表明:(1)三峡库区共鉴定出浮游植物8门105属266种,年平均丰度为6.4×10⁴ cells/L,年平均生物量为0.038 mg/L。不同季节优势种组成不同,变异直链藻(Melosira varians Agardh)、骨条藻(Sheletonema spp.)、脆杆藻(Fragilaria spp.)为全年优势种。(2)三峡库区共划分24个功能群,B、D、MP、S1、P、Y为优势功能群。RDA分析表明,电导率、总氮、化学需氧量、总磷、pH、总溶解性固体与三峡库区四季功能群呈现显著关系。(3)相较于丰度、生物量和多样性水质评价结果,浮游植物Q指数更适用于三峡库区水生态评价,显示三峡库区干流水生态环境总体较好,但春、夏两季支流浮游植物...     

Dominance patterns in macroalgal and phytoplankton biomass under different nutrient loads in subtropical coastal lagoons of the SE Gulf of California

Nine macroalgal blooms were studied in five coastal lagoons of the SE Gulf of California. The nutrient loads from point and diffuse sources were estimated in the proximity of the macroalgal blooms. Chlorophyll a and macroalgal biomass were measured during the dry, rainy and cold seasons. Shrimp farms were the main point source of nitrogen and phosphorus loads for the lagoons. High biomasses were found during the dry season for phytoplankton at site 6 (791.7 ± 34.6 mg m⁻²) and during the rainy season for macroalgae at site 4 (296.0 ± 82.4 g m⁻²). Depending on the season, the phytoplankton biomass ranged between 40.0 and 791.7 mg m⁻² and the macroalgal biomass between 1 and 296.0 g m⁻². The bulk biomass (phytoplankton + macroalgal) displayed the same tendency as the nutrient loads entering the coastal lagoons. Phytoplankton and macroalgal biomass presented a significant correlation with the atomic N:P ratio.     

黄河干流浮游植物群落特征及其对水质的指示作用

2008年5-6月和9-10月对黄河干流13个河段和4座水库的浮游植物群落及其环境进行了全面调查.共鉴定浮游植物8门83属150种,其中有硅藻59种,绿藻55种,蓝藻24种,甲藻4种,裸藻4种,金藻2种,黄藻1种和隐藻1种,平均细胞密度和生物量分别为126.90×104cells/L和0.940mg/L.从大的格局上看,浮游植物群落在种类数、种类组成和现存量上均存在较明显的空间分异,这种分异性可从河流流速、泥沙含量和受污染程度得到解释.根据浮游植物污染指示种和Shannon-Wiener多样性指数分析,黄河干流各河段多受到不同程度的污染.与1986年的资料相比,黄河干流浮游植物组成发生了明显变化,属数下降了9.8%,而平均生物量升高了128.7%,且在种类组成上也发生了明显的变化,表明河流污染程度的加剧.     

Forecasting Phytoplankton Development in a Designed Low-Head Reservoir on the Don River

Water Resources - The article presents the results of hydroecological modeling of variations of phytoplankton biomass, biogenic substances, and dissolved oxygen concentration in a reach of the...     

Phytoplankton structure and microcystine concentration in the highly eutrophic Nero Lake

The results of observations of some abiotic (water transparency, light intensity, depth, biogenic element concentrations) and algological (chlorophyll concentration, phytoplankton abundance and biomass, the concentration of microcystines—toxins of blue-green algae) characteristics of Lake Nero are given for study periods of 1999–2004 and 2005–2007. Variations of these characteristics in the latter period are shown to be significant. The lake phytoplankton is found to pass in a «catastrophic” manner to monodomination of planktotrichaetic complex of blue-green algae. High-performance liquid chromatography was used for the first time to determine the concentration of microcystines MC-LR and MC-RR in Lake Nero seston. The presence of these types of microcystines in samples was confirmed by mass-spectrometry. A statistically significant correlation was found to exist between the total concentrations of microcystines and the biomass of species of Microcystis genus, suggesting the possible toxicity of representatives of this type of algae in Lake Nero.     

浙江瓯江开潭水库库区浮游植物与水质的关系

通过2001年7月-2002年6月对瓯江开潭水库库区水体浮游植物的调查,以及对溶解氧和叶绿素a等理化指标的逐月测定,结果表明：该水域共有浮游植物7门40属82种(包括变种),其中以绿藻门和硅藻门的种类占优势,浮游植物的群落类型为绿藻型和硅藻型为主,种类和数量随季节和水域不同而呈现差异,水体营养特征为浮游植物响应型,水体向中营养化发展趋势明显,部分水体受到不同程度污染．     

以鲢、鳙养殖为主的长江中下游武山湖浮游植物群落结构特征

武山湖是紧邻长江的通江型富营养化湖泊,是国家级湿地公园.为切实了解该湖在以鲢、鳙养殖为主的情况下浮游植物结构特征,于2017年9月-2018年8月对其浮游植物群落结构特征及水质开展了监测.监测结果表明武山湖水质全年处于轻度富营养到重度富营养水平之间;12次共采集浮游植物7门100种（属）,浮游植物优势种共有23种,其中蓝藻门有9种,绿藻门有8种,硅藻门和隐藻门各有3种.夏季和秋季蓝藻门优势种最多且优势度高,冬季和春季绿藻门和硅藻门优势种多且优势度高.武山湖浮游植物每月优势度最大的种类主要有蓝藻门微囊藻和细小平裂藻、绿藻门小球藻以及硅藻门小环藻.浮游植物生物量峰值出现在6月,达34.77 mg/L;丰度峰值出现在7月,达341.46×10⁶ cells/L.冗余分析（RDA）和线性相关分析均表明浮游植物丰度和生物量与总磷、温度和pH均呈显著正相关,且蓝藻门生物量和丰度以及优势属与总磷和温度均呈显著正相关.研究结果表明武山湖浮游植物丰度和生物量在夏季均很高,发生蓝藻水华的风险较大.相对于氮,磷是更重要的限制浮游植物生长的营养元素.     

Predicting the effects of sediment based internal nutrient loads on eutrophication in Kücükcekmece Lagoon for rehabilitation planning

In deep stratified coastal lagoons, hypoxic waters that result from phytoplankton decomposition in the stratified bottom waters are often associated with eutrophication. Decomposing biomass reaches the bottom sediments and enriches them with nutrients and organic matter. Nutrients trapped in sediments are released with time and promote excessive phytoplankton growth in the surface water. Because eutrophication in lentic ecosystems progresses in a self-fuelling cycle, outflow is the only available process for exporting excess nutrients to recover from eutrophication. Thus, rehabilitation of eutrophic coastal lagoons that have limited seawater interactions is a long term process. The importance of nutrient release from sediments on eutrophication and the delay effect of internal nutrient loading on the rehabilitation of a eutrophic coastal lagoon with limited seawater exchange were analysed in this study.An ecological model that couples the water column and the sediment diagenesis processes, was developed for water quality management purposes. Our findings indicate that the recovery of the Lagoon from eutrophication will be taken decades even in the absence of external nutrient loading. Therefore, we suggest applying rehabilitation strategies that control the nutrient fluxes from sediments for a faster recovery from heavily eutrophic conditions. Land-based nutrient sources must also be controlled because they feed water column and the bottom sediments with nutrients.     

Phytoplankton abundance, biomass and diversity within and between Pantanal wetland habitats

During the high water season, the flooding reduces environmental heterogeneity in aquatic ecosystems of the Pantanal wetland. When the water level recedes, lakes and channels are formed as individual systems. Therefore, we expected the spatial heterogeneity during the low water phase resulting in changes on biological communities leading to high phytoplankton abundance, biomass and diversity within and between habitats. To test this hypothesis, we analyzed eight freshwater systems (five oxbow lakes, two channels, and the river) during the low water period. Phytoplankton biomass, abundance, diversity (alpha, beta, gamma) and diversity metrics as richness (species per sample), Shannon diversity (H′) and evenness were measured in all systems along with nutrient concentrations, zooplankton and bacteria abundances. We found 97 species as gamma diversity. The alpha diversity was unexpectedly low in comparison to most other South American floodplain systems (38 species in river, 24 in channels and 29 in lakes). Also, the systems are relatively similar in composition (beta diversity, 28%). Connectivity differences between systems highlighted differences in phytoplankton abundance and biomass (fresh weight) ranging from 1428 ind mL⁻¹ (river) to 3710 ind mL⁻¹ (lakes) and from 0.71 mg L⁻¹ (river) to 2.9 mg L⁻¹ (lakes), respectively. However, our results did not indicate significant differences in phytoplankton species richness between the systems during the low water. Our main conclusions are that local factors may be responsible for changes on phytoplankton community and the time of isolation during the low water phase was not sufficient to promote changes in phytoplankton diversity between the habitats.     

东巢湖湖滨农田生态拦截沟中浮游植物群落结构

在巢湖市烔炀镇西宋村农田示范基地中建立生态拦截沟来处理农业生产排放的农业面源污水,就生态拦截沟中浮游植物丰度、生物量和群落结构进行了研究.实验历时6个月,研究中共检测到浮游植物9门48属75种.研究发现尽管农田生态拦截沟中的水生植被能有效削减水体中的氮、磷营养盐,但对浮游植物群落结构产生的影响不大.生态拦截沟中主要藻类为绿藻、蓝藻和硅藻,且出水口蓝藻所占比例较进水口有显著上升.生态拦截前后浮游植物优势种类的变化不大,主要为蓝藻门的铜绿微囊藻(Microcystis aeruginosa)、绿藻门的微球衣藻(Chlamydomonas microsphaera)和硅藻门的孟氏小环藻(Cyclotell meneghiniana)等.藻类生物多样性研究表明生态拦截沟中的水体主要为清洁或寡污型水体,仅在夏季的7月份出现了轻微的水体污染.典型对应分析发现,TN/TP对浮游植物种类分布的解释度最高.同时,发现水体总磷的对数、总溶解磷的对数与藻类的生物量呈正比,而TN/TP与藻类的生物量呈反比.研究表明农田生态拦截沟尽管具有削减农业氮、磷营养盐面源污染的作用,但不能有效地降低水体中蓝藻的生物量.农业面源污水中的藻类营养盐限制主要为磷限制,削减农田径流中的磷含量是控制巢湖流域水体富营养化和遏制蓝藻水华的关键环节.     

热带富营养化湖泊中浮游植物的脂肪酸组成与分布

星湖位于广东省．是一个热带地区的湖泊．本文测定和分析了该湖的两个子湖仙女湖和中心湖浮游植物群落的脂肪酸组成,探讨了浮游植物群落特征与脂肪酸组成之间的关系．两个子湖的富营养化程度较高,其中中心湖更严重．仙女湖的浮游植物群落以蓝藻为主导,而在中心湖则蓝藻或金藻占优势．浮游植物样品中检测到的脂肪酸碳链长为16碳到22碳．其中饱和脂肪酸和单不饱和脂肪酸种类较少,均有3种;而高不饱和脂肪酸的种类相对较多．两个子湖的脂肪酸均以饱和脂肪酸为主,高不饱和脂肪酸浓度相对较低．对于单一的脂肪酸种类来说,C16：0浓度最高,其浓度与蓝藻数量有很高的相关性(R^2=0．955,P=0．001),表明样品中的C16：0主要来源于蓝藻．而富含EPA(二十碳五烯酸)的硅藻和隐藻生物量高时其浮游植物的EPA浓度也较高;在中心湖中高浓度的DHA(二十二碳六烯酸)主要来源于金藻总之．两个子湖泊的脂肪酸组成与浮游植物群落结构特征基本一致．