邵伯湖底栖动物群落结构调查研究及水质生态评价

2018年1—12月对邵伯湖进行了底栖动物监测分析,共鉴定出底栖动物16种,底栖动物主要优势种为苏氏尾鳃蚓、霍甫水丝蚓、红裸须摇蚊和环棱螺。底栖动物密度介于46～115 ind./m~2,平均密度为81 ind./m~2。底栖动物生物量介于2.928～23.405 g/m~2,平均生物量为13.665 g/m~2。通过Wright指数、Goodnight指数、BPI生物学指数和Shannon-Wiener多样性指数对邵伯湖进行了水质生态评价。     

梯级水库对南渡江干流底栖动物丰枯水期沿程变化的影响

为探讨梯级水库影响下河流底栖动物种群在河流丰枯水期的沿程变化规律,通过对丰水期(8月)和枯水期(1月)采样处理和计量鉴定,对我国大型热带河流——海南南渡江干流的底栖动物的生物量、丰度、多样性、均匀度在丰枯水期的沿程变化进行了分析。结果表明:丰枯水期共检测出底栖动物2门4纲22种,各物种丰度在0～236个/m~2之间,生物量在0.27～31.5g/m~2之间;底栖动物种群结构沿程变化受梯级水库建设影响较大;丰、枯水量变化对底栖动物群落影响显著,受枯水期水库蓄水大幅度改变水流连通性影响,枯水期底栖动物种类沿程变化幅度大于丰水期;与温带河流不同,南渡江干流大多数底栖动物种类在冬季仍能较好繁殖,枯水期底栖动物丰度和生物量均大于丰水期。     

漓江秋季大型底栖动物群落结构特征分析

2009年8—9月,通过对漓江流域大型底栖动物进行详细调查,共鉴定大型底栖动物3门6纲24种,其中昆虫纲种类最多,腹足纲次之。以优势度指数大于0.02作为判别标准,判断出调查区域内全流域以及上中下游的优势种。调查结果表明:漓江大型底栖动物平均总密度与平均总生物量分别为682个/m2和152.77g/m2。两者均为下游最高、中游次之、上游最低。其Shannon-wiener多样性指数、Pielou均匀度指数和Marglef丰富度指数的平均值分别为2.37、0.61和6.01。并依照漓江上、中、下游3个江段150个采样点的数据作出丰度/生物量曲线,分析该曲线,认为漓江上游大型底栖动物群落处于未受干扰的状态;其他两个江段则均受到了轻度的干扰。     

苕溪上游临安段底栖动物群落结构与水质生物学评价

2013年6月和10月,对苕溪上游临安段9个断面开展了底栖动物的调查研究,并利用生物指数对水质状况进行评价。调查期间共采集到底栖动物4门6纲27科46种,其中昆虫纲种类最多,出现频次最高的种是霍甫水丝蚓(Limnodrilus hoffmeisteri)、羽摇蚊属(Chironomus sp.)和苏氏尾鳃蚓(Branchiura sowerbyi)。底栖动物的平均密度和平均生物量分别为1 111 ind./m2和24.18 g/m2,按耐污值来划分以耐污种群和中等耐污种群占优势,共计占91.3%。利用底栖动物BI生物指数评价结果表明,苕溪上游临安段水质状况较差,除S2断面外,均处于中污染—重污染状态。     

大金钟水库水生生物群落结构特征

于2016年9、10、12月对大金钟水库开展了浮游植物、浮游动物、底栖动物和水生高等植物调查,共发现浮游植物7门63个分类单位,浮游动物15属20种,大型底栖动物2门3纲6目8科12属,水生高等植物13科14属14种。浮游植物丰度164.1×10~4~2 452.8×10~4cells/L,浮游动物丰度208.25~448 ind/L。基于底栖动物的ODP法和BI指数评价结果显示,实施水生态修复工程后,大金钟水库水质可能由轻污染向清洁好转。     

猫跳河流域底栖动物群落结构与水质生物评价

调查河流底栖动物群落结构并进行水质生物评价,对制定流域环境管理策略有重要意义。为摸清长江二级支流猫跳河流域水生态环境状况,用底栖动物作为指示物种,对猫跳河水污染状况进行评价。调查发现：猫跳河有底栖动物82种,隶属于4门7纲51科,其中水生昆虫的种数占据明显优势。底栖动物总平均个体密度为84 ind./m2,总平均生物量密度为11.01 g/m2;Shannon-Wiener多样性指数平均值为1.57,Pielou均匀度指数平均值为0.66。水质生物评价结果表明,猫跳河流域大多处于污染状态,其中支流受污染的状况比干流更严重。Shannon-Wiener多样性指数和BMWP记分系统2种评价方法的结果存在一定差异,采用BMWP记分评价得到的结果普遍劣于Shannon-Wiener多样性指数评价的结果。     

白石水库底栖动物群落结构特征及多样性研究

本研究采用野外生态学方法,于2013年9月—2014年7月期间,对白石水库底栖群落结构及多样性开展了调查,共调查4季10月。结果表明,白石水库的底栖动物共检出2门14种,密度为512ind/m²,生物量为113.35g/m²,密度随季节变动情况是春季>冬季>夏季>秋季,生物量随季节变动情况是春季>夏季>冬季>秋季,平均多样性指数(Shannon-Wiener)为2.05,平均均匀度指数(J)为0.54,此外对白石水库底栖动物群落结构进行了分析,并与其他辽宁省水库底栖动物群落结构进行了比较。针对白石水库底栖动物群落结构,提出了水生态健康对策,以期能为发展白石水库优水渔业提供基础数据。     

武江梯级水电站开发对底栖动物群落结构的影响

为了解梯级电站开发对底栖动物群落结构和多样性的影响,于2014年11月对武江韶关段的8个断面底栖动物进行了调查,包括3个自然河段和5个梯级水库,共采集到大型底栖动物3门5纲29种,河蚬、淡水壳菜、狭萝卜螺和霍甫水丝蚓是最主要的密度优势种,梯级水库底栖动物密度均低于自然河段。多样性指数显示:由于底质改变和人为活动的干扰,梯级水库的水质均受到不同程度的污染。     

锦凌水库水生生物群落结构及鱼产力研究

于2019年5月和2020年6月对锦凌水库的水质、浮游生物和底栖动物进行了调查研究.结果显示,锦凌水库浮游植物共检出8门116种,平均密度为7.0×106ind./L,平均生物量为3.03mg/L;浮游动物共检出4类70种,平均密度为2192ind./L,平均生物量为3.88mg/L;底栖动物共检出3门9种,平均密度为...     

用生态学观点评价大伙房水库水质

2001年对大伙房水库6个采样站(点)进行了不同季节浮游植物、底栖动物群落特征调查,共发现藻类8门、174种,底栖动物34种。结合大伙房水库建库以来的水生生物监测资料,分析水生生物种类组成,数量变化和演替规律。水质生态学评价表明,大伙房水库只受到轻度污染,水质等级为2级。     

白洋淀浮游动物生物多样性及水生态评价

为研究白洋淀浮游动物生物多样性和水生态状况,2012年6月和10月对浮游动物进行了采样调查。结果表明:白洋淀共鉴定出浮游动物37种,其中枝角类最多,占总数的51.4%;各监测站点浮游动物密度为2480~7580ind/L,平均密度4160 ind/L;生物量为0.46~1.81 mg/L,平均生物量1.24 mg/L。Margalef多样性指数为1.83~3.51。浮游动物损失指数表明,整个白洋淀地区浮游动物状况相对于历史数据均有不同程度变差。用浮游动物多样性指数评价水质状况,白洋淀处于中度污染水平;综合浮游动物生物量评价水体营养级别标准,考虑到富营养化指示物种的存在,综合评价白洋淀水体处于富营养状态。     

Lake Champlain offshore benthic invertebrate community before and after zebra mussel invasion

Benthic invertebrates are important bio-indicators of water quality and play a significant role in aquatic systems. Lake Champlain has limited benthic invertebrate data which hinders development of food web models, assessment of invasive species impacts, and evaluation of management actions. In June 2016, we assessed benthic invertebrates along three transects in the main basin of Lake Champlain ranging from 5 to 100?m, and then compared results to densities from a limited survey in 1991 prior to the zebra mussel (Dreissena polymorpha) invasion. In 2016, total biomass and density were 1–2 orders of magnitude greater at 5?m than at 20–100?m. Zebra mussels, chironomids, oligochaetes, and gastropods were dominant at 5?m, and oligochaetes and sphaeriids were dominant at 20–100?m. Total density at the 5-m site was 94% lower in 2016 compared to 1991, but similar at the 100-m site. Diporeia, while abundant in many freshwater bodies, is historically rare in Lake Champlain and was not detected in our sampling. Because Lake Champlain benthic invertebrate densities are low and display dissimilar distributions to the Great Lakes, we hypothesize the offshore fish community is likely much more reliant on pelagic rather than benthic production. Although the current composition and biomass suggest the benthic community in Lake Champlain may not be greatly impacted by an invasion of quagga mussel (D. rostriformis bugensis), the potential for quaggas to re-route energy from pelagic to benthic habitats, as it has in the Great Lakes, could limit the Lake Champlain offshore fish community.     

Distribution of macrobenthic fauna in Phawong and U-Taphao canals flowing into a lagoonal lake, Songkhla, Thailand

The macrobenthic fauna of two discharge ecosystems, Phawong Canal and U-Taphao Canal flowing into Songkhla Lake in Thailand, were studied from August 1994 to August 1995. The salinity of Phawong Canal and U-Taphao Canal ranged from 0.1 to 27.8 and 0.1 to 17.0 practical salinity units (PSU), respectively. The biochemical oxygen demand (BOD) of Phawong Canal ranged from 2.5 to 33.0 mg L⁻¹, while that of U-Taphao Canal ranged from 1.1 to 12.6 mg L⁻¹. Temporal changes in the number of species and individuals were determined throughout a year. During the season of heavy rains (November– December), the density and number of most species decreased markedly. Only chironomid larvae increased and these were distributed in the uppermost reaches of the canals during this period. Sixty-two and 52 species of macrobenthic fauna were found in Phawong Canal and U-Taphao Canal, respectively; however, the abundance and number of species collected at each sampling was very low in the upper reaches of the canals. The most numerous benthic fauna in the Phawong Canal were polychaetes, followed by amphipods. Pelecypods and gastropods were the dominant groups in U-Taphao Canal. A distribution pattern of macrobenthic fauna associated with pollution gradients (BOD) was observed only at Phawong Canal. In addition, species diversity according to the Shannon-Wiener index only was not applicable to the assessment of benthic environmental health when the few individuals found were evenly distributed among the few species present at U-Taphao Canal. It is recommended that a coastal care project be established by the appropriate government agencies in the study areas.     

Distribution of macrobenthic fauna in Phawong and U-Taphao canals flowing into a lagoonal lake, Songkhla, Thailand

The macrobenthic fauna of two discharge ecosystems, Phawong Canal and U-Taphao Canal flowing into Songkhla Lake in Thailand, were studied from August 1994 to August 1995. The salinity of Phawong Canal and U-Taphao Canal ranged from 0.1 to 27.8 and 0.1 to 17.0 practical salinity units (PSU), respectively. The biochemical oxygen demand (BOD) of Phawong Canal ranged from 2.5 to 33.0 mg L⁻¹, while that of U-Taphao Canal ranged from 1.1 to 12.6 mg L⁻¹. Temporal changes in the number of species and individuals were determined throughout a year. During the season of heavy rains (November– December), the density and number of most species decreased markedly. Only chironomid larvae increased and these were distributed in the uppermost reaches of the canals during this period. Sixty-two and 52 species of macrobenthic fauna were found in Phawong Canal and U-Taphao Canal, respectively; however, the abundance and number of species collected at each sampling was very low in the upper reaches of the canals. The most numerous benthic fauna in the Phawong Canal were polychaetes, followed by amphipods. Pelecypods and gastropods were the dominant groups in U-Taphao Canal. A distribution pattern of macrobenthic fauna associated with pollution gradients (BOD) was observed only at Phawong Canal. In addition, species diversity according to the Shannon-Wiener index only was not applicable to the assessment of benthic environmental health when the few individuals found were evenly distributed among the few species present at U-Taphao Canal. It is recommended that a coastal care project be established by the appropriate government agencies in the study areas.     

Biodiversity characteristics of small high-altitude tropical man-made reservoirs in the Eastern Rift Valley, Kenya

The biodiversity characteristics in eight small (0.065–0.249 km²) public man‐made reservoirs in the central part of the Eastern Rift Valley, Kenya, were studied between 1995 and 1998. A total of 71 phytoplankton species belonging to approximately 50 taxa were identified. Chlorophytes and cyanobacteria dominated the crop. The dominant taxa included Botryococcus, Syunura, Microsystis, Anabaena, and Cosmarium. A total of over 40 zooplankton species were identified. The community was composed mainly of crustacea, rotifers and protozoa. The most dominant group was Keratella but Brachionus and Nauplius were equally abundant. The diversity and abundance of benthic invertebrates was not high, and only 18 species were identified throughout the study period with the range of species number being 1–7 per reservoir. The benthic fauna was mainly composed of Lumbriculidae and Chironomid worms. A total of six monthly bird counts found an average of 60 birds per reservoir, and a total of 49 species was identified. Ducks, geese and coots dominated the waterfowl, especially during the dry season. Large‐scale breeding by Black‐headed Heron (Ardea melanocephala ) and Little Egret (Egretta garzetta ) was observed in one of the sites, and other species were also breeding in the reservoirs. The population of waterbirds in reservoirs was closely related to the biomass of benthic invertebrates, and the findings of the study indicate that the structure and dynamics of life forms within small man‐made reservoirs can serve as excellent sensors and indicators of the state of watershed health.     

An Investigation of the Impacts of Agricultural Runoff on the Water Quality and Aquatic Organisms in a Lowveld Sand River System in Southeast Zimbabwe

In this research we examined the hypothesis that agricultural pollution is a key determinant of variability in nutrients concentrations and benthic fauna in a semi-arid tropical lowveld region of southeast Zimbabwe. Water quality was monitored in the river water column and river bottom sediments at a time when dissolved oxygen concentration was thought to be very low during the winter period in the rivers passing through low input agricultural sections and intensive commercial agricultural sections. The surveys used established chemical methods and biological methods. Benthic fauna assemblages were used to complement chemical cases of nutrient loading at localities chosen for sampling. Unpolluted control sites were not significantly different (t test, p < 0.05) from polluted sites in levels in mean values of dissolved oxygen, conductivity, total dissolved solids and mean density (no.m²) of benthic invertebrates in May. Significant differences (t test, p < 0.05) were not found in mean values of calcium, magnesium, potassium, total nitrogen, nitrate nitrogen, ammonia nitrogen and total phosphorous in river bottom sediments in May and August. These data certainly do not support the notion that the Runde River is severely polluted by the upstream agricultural activities and the hypothesis that agricultural runoff is a key determinant of water quality is rejected. As the data suggests the Runde River may be receiving moderate nutrient pollution. The positive effects of moderate eutrophication on fish catch and the trade-off in pollution implied here needs to be addressed by appropriate agricultural and environmental policies that relate to water pollution and land use.     

Annotated Checklist of the Free-Living Copepods of the Great Lakes

An annotated checklist of the free-living copepods of the Laurentian Great Lakes is developed on the basis of published records. Synonymies are included for each species, relating, wherever possible, invalid names in the literature with currently recognized taxonomy. Twelve species of calanoids, six species of planktonic cyclopoids, nine species of benthic/ littoral cyclopoids, and fourteen species of harpacticoids have been reported from the Great Lakes. Ten of the calanoids and four of the cyclopoids are characteristic of limnetic waters. Three calanoids and two planktonic cyclopoids have been reported infrequently and are perhaps accidental occurrences. The composition of the planktonic copepod fauna in most subregions of the Great Lakes is well-known. In contrast, the sampling of benthic/littoral cyclopoids and harpacticoids has been so infrequent that their kinds, areas of occurrence, and relative abundances are still poorly understood.     

水电开发影响下河岸带植被结构和生物量分布

为了解水电开发不同阶段对河岸带植被的影响差异,在澜沧江中下游小湾电站、漫湾库区、漫湾坝下、大朝山库区、大朝山坝下、景洪电站河岸带设置6个样带进行植被结构指标和生物量空间分布特征调查分析。结果表明:澜沧江中下游河岸带植被以乔木为主体,乔木层结构指标以已建库区和坝下样带较高,灌木层和草本层结构指标以在建电站和坝下样带较高;已建库区、坝下和在建电站样带乔木层和群落生物量的最高值分别出现在距离河岸100,50 m和200 m处;乔木层生物量以库区样带最高,灌木层生物量以坝下样带最高,草本层生物量以在建电站样带最高;库区和坝下样带群落生物量大致相当,高于在建电站样带;漫湾库区及其坝下乔木层结构指标以及群落生物量相对变化幅度小于大朝山库区及其坝下样带,小湾样带小于景洪样带。研究区植被结构和生物量的分布格局反映了库区植被恢复程度的差异和电站施工影响强度的差异。     

Non-native Dreissena associated with increased native benthic community abundance with greater lake depth

Although the typical interaction between non-native invasive species and native species is considered to be negative, in some cases, non-native species may facilitate native species. Zebra and quagga mussels (Dreissena spp.) are aggressive invaders in freshwater systems, and they can alter energy flow by diverting nutrients from pelagic to benthic food-webs. In the last two decades, quagga mussels have largely replaced zebra mussels in shallow regions of the Laurentian Great Lakes and colonized deeper waters previously devoid of all dreissenids. Here, we aim to characterize potential positive effects of dreissenids in relation to depth on the benthic community in lakes Michigan and Huron. For this study, we used benthic survey data collected from Lake Michigan in 2015 and Lake Huron in 2017 and annual U.S. EPA Great Lakes National Program Office Long-term Biology Monitoring Program data for both lakes from 1998 to 2019. Benthic species richness and abundance (excluding dreissenids) in both lakes were almost three-fold higher in the nearshore (<70 m) compared to offshore (>70 m) communities. We found that, even though abundance of benthic invertebrates decreased with increased depth, total benthos density and biomass were higher in the presence than in the absence of quagga mussels in both lakes. Moreover, increased quagga mussel density and biomass with depth offset the lower benthos density and biomass at deeper depths, and samples with dreissenids had high densities of oligochaetes in both nearshore and offshore communities. These patterns are consistent with facilitative effects of quagga mussels on both shallow and deep-water benthic communities.     

Influence of environmental factors on abundance and temporal variation of benthic fauna resources in the eutrophic Tha Chin estuary, Samut Sakhon province, Thailand

The influence of environmental factors on the abundance and temporal variation of benthic fauna resources was studied in the eutrophic Tha Chin estuary located in Samut Sakhon province. The objectives were to analyze the status of abundance and temporal variation of the benthic fauna and to clarify the impacts from environmental factors (water and sediment quality). Field surveys were conducted monthly from August 2007 to March 2008 at 11 sampling stations in the estuary. Based on freshwater runoff volumes, the high-, medium-, and low-loading periods were categorized to be from August to October 2007, November to December 2007, and January to March 2008, respectively. The benthic fauna resources were composed of 57 species in eight phyla. Annelids were the dominant species (with the maximum density being 19,885 individuals/m2), followed by the mollusks. Both densities decreased during the low-loading period in 2008. Water quality deteriorated during the high-loading period. Land-based wastewater discharges decreased the levels of salinity and dissolved oxygen but dramatically increased various nutrients. Consequently, the sediment quality deteriorated during the medium-loading period. Bottom deposits during this time depicted high accumulation of acid volatile sulfides (more than 0.76 mg/g dry weight). Analyzing the environmental relationships, deposit feeders (for example, Nereis sp. and Prionospio sp.) and a clam (Arcuatula sp.) showed potential as bio-indicators for environmental monitoring. The overall results revealed the importance of changes in the water and sediment qualities that had an influence on related benthic resources. The increase in the level of NH4(+)-N had a negative impact on the economic clam species, while the sedimentary TOM showed positive correlation (P < 0.05) with this increase. The succession of groups based on feeding behavior seemed to correspond with stress in eutrophication along the salinity gradient and in different estuarine parts. In addition, the economic clam population decreased noticeably during the medium-loading period, as a consequence of deteriorated sediment conditions. Thus, the land-based runoff should be controlled for the protection of resources. Further effective sustainable management will be enhanced by giving serious consideration to an eco-based zoning scheme for conservation and restoration of the Tha Chin estuary.