Seasonal dynamics of crustacean zooplankton community structure in Erhai Lake, a plateau lake, with reference to phytoplankton and environmental factors

The seasonal dynamics of a crustacean zooplankton community in Erhai Lake was investigated from May 2010 to April 2011. In total, 11 species were recorded, including six(6 genera) cladoceran and five(5 genera) copepod species. The crustacean zooplankton densities ranged from 24.3 to 155.4 ind./L. In winter and spring, the large-bodied cladoceran Daphnia galeata dominated the crustacean plankton community. In summer and autumn, when the colonial or filamentous algae dominated the phytoplankton communities, the small-bodied species(e.g. B osmina fatalis, Ceriodaphnia quadrangular, and Mesocyclops leuckarti) replaced the large-bodied ones. One-way ANOVA and redundancy analysis revealed that community structure was dependent upon total nitrogen, total phosphorus, water temperature, transparency, and the biomass of small algae. The variation in both phytoplankton structure and environmental variables were important factors in the seasonal succession of crustacean zooplankton structure in Erhai Lake.

The Impact of Turbidity on Zooplankton Densities in Lake Kinneret (Israel)

Spatial survey of zooplankton community composition within the upper 10 m layer in Lake Kinneret was carried out. Samples were collected by plankton net (63 μ mesh size) and counted organisms were sorted by 2 groups: 1) Large-including Copepodite and adult Cyclopoid copepods and Cladocerans;2) Small nauplii and rotifers. It was found that in the northern part of the lake where turbidity is high, the density of small organisms is relatively lower, and in other parts of the lake where water is less turbid, large organisms are relatively less abundant. Speculative assumption about the impact of fish feeding behavior on that is presented.

Size-dependent responses of zooplankton to submerged macrophyte restoration in a subtropical shallow lake

To explore the size-dependent responses of zooplankton to submerged macrophyte restoration, we collected macrophyte, zooplankton and water quality samples seasonally from a subtropical shallow lake from 2010 to 2012. Special attention was given to changes in rotifers and crustaceans(cladocerans and copepods). The rotifers were grouped into three size classes(<200 μm, 200 μm–400 μm, >400 μm) to explore their size-related responses to macrophyte restoration. The results showed that during the restoration, the annual mean biomass and macrophyte coverage increased significantly from 0 to 637 g/m^2 and 0 to 27%, respectively. In response, the density and biomass of crustaceans and the crustacean-to-rotifer ratio increased significantly, while the rotifer density decreased significantly. Moreover, rotifers showed significant sizedependent responses to macrophyte restoration. Specially, rotifers <400 μm were significantly suppressed, while those ≥400 μm were significantly encouraged. Overall, the population of large-sized zooplankton tended to boom, while that of small rotifers was inhibited during macrophyte restoration. Redundancy analysis(RDA) revealed positive correlations between macrophytes and crustaceans, rotifers and COD or Chl-a, but negative correlations between macrophytes and COD or Chl-a, and between crustaceans and Chl-a. Moreover, the results indicate that increased predation on phytoplankton by large-sized zooplankton might be an important mechanism for macrophyte restoration during development of aquatic ecosystems, and that this mechanism played a very important role in promoting the formation of a clear-water state in subtropical shallow lakes.

Community succession of zooplankton in marine derived saline lakes in antarctic continental margin

Ecological research has been made for quite a long period in some marine-derived saline lakes in the Vest-fold Hills, Antarctica. The results show distinct succession of zooplankton community in those lakes. The change in community structure of zooplankton is related directly to environmental evolution in nature and the variation of lake conditions, such as physical and chemical factors as well. In the Burton Lake, there is a rather stable annual fluctuation in both temperature and salinity, and the community has probably been in the stage of climax succession. The Fletcher Lake is still undergoing a process by unregular tide flood from nearby bay, so that zooplankton community has been changing due to variance in temperature and salinity.

高邮湖浮游生物多样性分析

于2021年对高邮湖的浮游生物多样性进行了两次采样分析,采样时间分别是3月和6月,布设了6个采样点。调查发现,高邮湖浮游植物78种,隶属于8门36科61属。绿藻门40种,占全部种类的51.3%;硅藻门16种,占全部种类的20.5%;蓝藻门8种,占全部种类的10.3%。浮游植物密度值为20.62×106cells/L,生物量9.96 mg/L。浮游动物55种,其中轮虫31种,占全部种类的56.4%;枝角类13种,占全部种类23.6%;桡足纲11种,占全部种类的20%。浮游动物密度为2730.2 ind./L、密度为1.21 mg/L。高邮湖浮游生物生物量和细胞密度存在明显的时空差异,均表现为丰水期大于枯水期,Shannon-Wiener指数和Margalef指数存在明显的空间变化差异。

Exploration of relationships between phytoplankton biomass and related environmental variables using multivariate statistic analysis in a eutrophic shallow lake:A 5-year study

Understanding the process of the changing phytoplankton patterns can be particularly useful in water quality improvement and management decisions. However, it is generally not easy to illustrate the interactions between phytoplankton biomass and related environmental variables given their high spatial and temporal heterogeneity. To elucidate relationships between them, in a eutrophic shallow lake, Taihu Lake, relative long-term data set of biotic and abiotic parameters of water quality in the lake were conducted using multivariate statistical analysis within seasonal periodicity. The results indicate that water temperature and total phosphorus （TP） played governing roles in phytoplankton dynamics in most seasons （i.e. temperature in winter, spring and summer; TP in spring, summer and autumn）; COD （chemical oxygen demand） and BOD （biological oxygen demand） presented significant positive relationships with phytoplankton biomass in spring, summer and autumn. However, a complex interplay was found between phytoplankton biomass and nitrogen considering significant positive relationships occurring between them in spring and autumn, and conversely negative ones in summer. As the predatory factor, zooplankton presented significant grazing-pressure on phytoplankton biomass during summer in view of negative relationship between them in the season. Significant feedback effects of phytoplankton development were identified in summer and autumn in view that significant relationships were obser,qed between phytoplankton biomass and pH, Trans （transparency of water） and DO. The results indicate that interactions between phyto：plankton biomass and related environmental variables are highly sensitive to seasonal periodicity, which improves understanding of different roles of biotic and abiotic variables upon phytoplankton variability, and hence, advances management methods for eutrophic lakes.

Chemical and biological features of the saline Lake Krasnovishnevoye(Baraba,Russia)in comparison with Lake Malinovoe(Kulunda,Russia):a reconnaissance study

The Baraba and Kulunda steppes are located in southwestern Siberia in an area with an arid continental climate. This paper presents results of the first study of the hypersaline Lake Krasnovishnevoye(Baraba steppe, TDS(total dissolved solids)=297 g/L, pH 7.88). The major chemical, mineralogical and biological features of the lake were studied and compared to those of Lake Malinovoe, a typical saline neutral lake of Kulunda steppe(TDS=396 g/L, pH 7.63). The phytoplankton composition and the culturable diversity of anoxygenic phototrophic bacteria from Lake Krasnovishnevoye correspond to the ones in the Kulunda lakes. Nevertheless, the peculiarities of water composition and regime of Lake Krasnovishnevoye reduce the biodiversity to prokaryotes and unicellular algae.

Lake-margin ecosystems of saline lakes of the Borzya group(Zabaikalsky Krai, Russia) during the initial filling phase

This article presents the results of hydrochemical and hydrobiological studies of shallow saline lakes of the Borzya group(Zabaikalsky Krai, Russia) at the initial filling phase. The lake-margin ecosystems of the studied lakes are characterized by varying degrees of salinity from polyhaline to brine water. Cyclical variations of meteorological conditions and high salinity determined that the compositions of the aquatic organisms are specific, mostly between stenohaline and euryhaline species, the quantities are low, and the community structures are simple.

Trophic State Evaluation of a Large Mediterranean Lake Utilizing Abiotic and Biotic Elements

The trophic state of a freshwater ecosystem reflects its environmental quality. This is why several trophic indicators have been developed for such water bodies based on chemical, physical and biological parameters. Apart from that, there are several biotic elements which can be used in accessing the environmental condition of a freshwater ecosystem. Zooplankton organisms are important elements of the structure and function of lakes and are considered useful indicators of alterations in their trophic dynamics and ecological state related to changes in nutrient loading and climate. In accordance to the above, the present study is an attempt to assess the trophic condition of the largest lake in Greece (Lake Trichonis) through the investigation of the physicochemical elements, along with the biotic indications provided by a three-year study of the lake’s zooplankton. The present results, compared with previous studies conducted between 15 and 25 years before, showed that there was an increase in the maximum values of the concentrations of chlorophyll-α and nutrients, while there was a decrease in water transparency. The implementation of Carslon’s trophic state index (TSI) revealed that Lake Trichonis still remains an oligo-to mesotrophic ecosystem as it was in the past. However, although the zooplankton investigation showed several features that are common in oligotrophic lakes, there are certain eutrophic characteristics of the zooplankton community (e.g. abundance variation pattern, indicator species, seasonal succession of cladocerans) pointing out a different state of the ecosystem in comparison to the past. In conclusion, the use of a biotic element like zooplankton revealed that Lake Trichonis is experiencing a transitional condition towards the eutrophic state and points out the necessity for constant inspection and monitoring of this ecosystem.

泸沽湖水生生物群落及水生态环境质量研究

以云南泸沽湖水位站、水质站和水生态站2021年实测数据为研究材料,采用指标体系法(水位、水质、水生生物指标),对泸沽湖的水生态环境质量进行评估,探索建立适合于泸沽湖的水生态环境质量评价体系,以期为湖泊的水生态保护、修复与管理提供依据。结果显示:泸沽湖日平均水位均高于最低运行水位,最低运行水位均能得到保证;总体水质为Ⅰ类,水体清洁,属贫营养湖泊;浮游植物群落结构在种类组成上以绿藻门、硅藻门为主,转板藻、脆杆藻、星杆藻为优势种;浮游动物群落结构在种类组成上以轮虫、原生动物为主,侠盗虫、表壳虫、砂壳虫为优势种;砂壳虫、表壳虫、螺形龟甲轮虫、长刺异尾轮虫等是泸沽湖浮游动物的常见种,指示水体清洁;底栖动物群落结构在种类组成上以节肢动物门、软体动物门为主,优势种主要为齿斑摇蚊和多足摇蚊;浮游植物、浮游动物、底栖动物多样性一般,湖周断面多样性指数高于湖心断面,主汛期高于其他时段;水生态环境质量处于受干扰很小的最优状态。研究结果表明,转板藻以优势种出现在泸沽湖水体中对营养化进程是一种警示,应密切关注。

Long-term Changes in the Saline Lake Qarun(Egypt)

1 Introduction There is now ample evidence of the impacts of the recent climate change and anthropogenic activities on different saline lake ecosystems.All over the world salt lakes are threatened by climate change,water diversions upstream for agricultural purposes,watershed changes,introduction of aliens,etc.that result in catastrophic

Assessment of the Impact of the Nile Flood on Food Chain in Lake Nasser—Egypt, with Special Reference to Turbidity

This study aimed to assess the impact of the Nile flood with special reference to turbidity on the food chain in Lake Nasser water as one of the largest man-made lakes in Africa before the flood (BF) and after the flood (AF) seasons. To achieve that aim, subsurface water samples were collected from 11 sampling stations along the lake before and after the flood for analyzing the water turbidity, total suspended solids, and total phosphorus, as well as chlorophyll-a and zooplankton to represent the food chain in the lake. Results showed an increase in water turbidity after the flood than that before the flood. Total suspended solids concentration displayed a similar trend as water turbidity. Chlorophyll-a concentration increased in AF all over the lake except at the entrance of the lake, as compared to the BF season. Zooplankton count was represented by copepods, cladocerans, and rotifers with the dominance of copepods in AF and rotifers in BF. The density of zooplankton was higher in the AF than the BF season. The negative impact of flood turbidity had appeared on crustacean organisms.

极低浮游动物丰度生境食蚊鱼仔稚鱼食物组成与摄食策略

浮游动物丰度可能是制约入侵鱼类仔稚鱼早期存活的关键因素。本文针对典型入侵鱼类食蚊鱼Gambu⁃sia affinis在岩溶泉潭中极低浮游动物丰度条件下的食物组成及摄食策略展开研究,以揭示其对上述特定环境的适应性。2021—2022年调查显示,星云湖“天中”龙潭群的浮游动物丰度均值仅为2.95 ind.·L^(−1),桡足类及其幼体是主要成分,数量百分比占53.4%~81.6%。食蚊鱼仔稚鱼消化道共检出31个食物种类;摄食策略表现为以桡足类(锯缘真剑水溞Eucylops serrulatus)为主的狭食性策略,也表现出具有在广食性策略与狭食性策略间切换的能力。食物充塞度指数(0.70±0.16)和身体肥满度指数(2.1±2.4)显示,食蚊鱼仔稚鱼具有良好的摄食条件和身体营养状况。在贫乏的饵料条件下,食蚊鱼仔稚鱼仍取得了生存上的成功,这提示食蚊鱼对高海拔贫营养水体同样具有极高入侵风险,其背后的生态学机制值得进一步深入探索。

洪泽湖湖滨带浮游动物群落结构及驱动因素

湖滨带在维持物种多样性、拦截陆源污染物、净化水质等方面发挥着重要作用。近年来,洪泽湖水体污染日益加重,湖滨带面临着围垦、养殖和泥沙淤积等严重威胁。为更好地理解洪泽湖湖滨带浮游动物群落结构的空间格局,运用主成分分析、冗余分析和方差分解,探究了洪泽湖湖滨带浮游动物的密度、生物量和种类结构组成,以及群落多样性和优势种的特征,分析上述参数随环境因子的变化趋势。结果表明,洪泽湖湖滨带浮游动物平均丰度为821.65 ind./L,平均生物量为1247.45μg/L,成子湖西浮游动物丰度较高,物种较为丰富;淮河口和东部湖岸丰度较低,多样性较低。主成分分析和冗余分析结果表明,溶解性总磷、悬浮物、叶绿素a、COD、溶解性有机碳、水草盖度、pH、溶解氧和风浪扰动是湖滨带主要环境影响因子,与轮虫物种的空间分布具有显著相关性。方差分解结果表明,轮虫主要受到水化学环境因子及其与食物饵料的交互作用,枝角类受水深、浊度和悬浮物等物理生境因子的影响,磷酸盐、pH、风浪扰动和悬浮物与水化学的交互作用对桡足类有明显影响,多样性指数主要受水化学环境因子、物理生境因子、食物饵料的交互作用影响。可见,加强洪泽湖湖滨带生态环境保护和综合管理对维持浮游生物群落结构稳定具有重要意义。

不同植物组合的生态浮床对浅水富营养化湖泊水质净化效果及浮游动物群落结构的影响

为探究不同植物组合的生态浮床对浅水富营养化湖泊的水质净化效果及浮游动物群落结构的影响,于2021年6月对太湖梅梁湾示范区内已实施围网和围隔设施下的不同植物组合[美人蕉(Canna indica)+菖蒲(Acorus calamus)+芦苇(Phragmites australis)和美人蕉(Canna indica)+水芹(Oenanthe javanica)+慈姑(Sagittaria sagittifolia)]的生态浮床中浮游动物群落结构进行了调查。结果表明:生态浮床对浅水富营养化湖泊水质的净化效果良好,围网及围隔修复区较对照区总氮(TN)、总磷(TP)、叶绿素a(Chl-a)和高锰酸盐指数(COD_(Mn))等水体营养盐指标均显著降低(P<0.05),水体透明度显著上升(P<0.05);围网及围隔修复区域浮游动物种类数由对照区域的23种增加到39种,且由单一耐污种转变为多种类共存,其中,围网修复区内植物组合1(美人蕉+菖蒲+芦苇)的生态浮床浮游动物生物量及丰度显著高于对照区(P<0.05),表明修复区比对照区具有更强的浮游动物多样性恢复能力;冗余分析显示,Tur、Chl-a、COD_(Mn)和pH是影响浮游动物群落变化的主要环境因子;不同植物组合的生态浮床均在净化水质的同时提高了浮游动物密度和生物量。研究表明,浅水富营养化湖泊中置入两组不同植物组合的生态浮床,均可改变浮游动物群落结构,进而改善水环境原位修复效果,尤其以围网设施下美人蕉+菖蒲+芦苇的植物组合修复效果最好,本研究结果可为浅水富营养化湖泊水环境保护和水生生物资源恢复提供科学依据。

荣成天鹅湖海草床及其邻近裸沙区浮游生物的时空变化特征

海草床是近海典型生态系统之一,为了解山东省荣成市天鹅湖鳗草(Zostera marina)海草床及其邻近裸沙区的浮游生物群落结构及时空变化特征,于2019年2月、5月、8月和11月,对天鹅湖鳗草海草床及其邻近裸沙区的浮游生物、海草床生态学特征及关键环境因子进行了周年调查,并应用典范对应分析(CCA)和冗余分析(RDA)探究了环境因子对浮游生物优势种的影响。结果显示,共发现浮游植物38种,隶属3门25属,其中,硅藻门(Bacilariophyta)种类最多(89.4%),甲藻门(Dinophyta)次之(7.8%);共发现浮游动物18种,幼虫3类,以甲壳动物(71.4%)为主;浮游生物种类数呈现显著的季节变化,且在11月达到最大值;海草床浮游植物和浮游动物的年平均丰度分别为5.4×10^(4)cells/m^(3)和1.6×10^(4)ind./m^(3),是裸沙区浮游植物和浮游动物年平均丰度的1.4倍和1.5倍;典范对应分析和冗余分析显示,海草床浮游生物优势种主要与水温、海草床的植株密度及生物量显著相关,而裸沙区浮游生物优势种则主要与水温、pH值及氨氮含量等环境因子显著相关。结果表明,天鹅湖海草床相比裸沙区具有更丰富的浮游生物。本研究为深入了解海草床生态系统的结构和功能提供了基础数据。

滇池不同湖区浮游动物群落稳定性及其驱动因子分析

为了揭示滇池不同湖区浮游动物群落稳定性及其驱动因子,于2020年对滇池草海、大泊口、外海3个具有一定空间分隔的区域,按季度进行4次采样调查。结果表明,大泊口区域的溶解氧、透明度指标显著高于外海,总氮、总磷、悬浮物、叶绿素a和化学需氧量等指标浓度显著低于外海,草海理化因子浓度介于大泊口与外海之间。研究期间3个区域共鉴定出浮游动物41属(枝角类12属、桡足类8属、轮虫21属),轮虫种类和密度均占较大比例。浮游动物年平均密度大泊口(7771.3 ind./L)>草海(2901.1 ind./L)>外海(634.8 ind./L);年平均生物量草海(3.72 mg/L)>大泊口(2.15 mg/L)>外海(2.09 mg/L)。非参数多元方差分析(PERMANOVA)与相似性百分比分析(SIMPER)结果表明,滇池3个区域间浮游动物群落结构差异极显著,导致大泊口与草海、外海群落结构呈极显著差异的属种为轮虫类群的种类,导致草海与外海群落结构呈极显著差异的属种为枝角类和轮虫类群的种类。此外,浮游动物群落稳定性与物种多样性呈显著的正相关关系,且经过生态修复后水质有所改善的湖区其浮游动物群落稳定性反而有所下降。Pearson相关性分析与冗余分析结果表明,影响浮游动物群落稳定性的主导环境因子为溶解氧、pH和叶绿素a。本研究结果发现滇池异质生境的浮游动物群落稳定性存在较大差异,生态修复后短期内水环境的变化会降低以耐污种为优势所形成的浮游动物群落稳定性。

新疆巴里坤盐湖浮游生物群落特征分析

为了解气候变化背景下新疆巴里坤盐湖的浮游生物群落结构特征和演化机制,于2020年10月、2021年5月和8月调查了巴里坤盐湖的浮游生物,依据形态学特征鉴定浮游生物属或种,统计分析Shannon-Wiener生物多样性指数、Pielous均匀度指数和Margalef物种丰富度指数。结果显示,巴里坤盐湖共鉴定出浮游植物7门62属,平均密度为9.34×104ind./L,平均生物量为1.97mg/L,以硅藻门、蓝藻门和绿藻门为主;浮游动物(除卤虫外)3门30属,以原生动物和轮虫为主,平均密度为146.45ind./L,平均生物量为0.51mg/L。浮游植物Shannon-Wiener生物多样性指数变化范围为0.822~3.509,浮游动物为0~2.919。巴里坤盐湖浮游生物物种组成、密度和生物量呈明显的水期变化和分布差异;较1990s浮游生物物种数目增加28属,密度显著降低(P<0.05),生物量有所增加(P>0.05),表明在全球气候变化和人类活动影响下巴里坤盐湖浮游生物群落特征发生了明显的变化,气候变化和人类活动导致的盐度和水温变化可能是造成浮游生物群落结构变化的主要因素,相关管理部门需予以重视。