Changes in the zooperiphyton structure in a small river along the spatial gradient

A total of 165 taxa have been recorded in the zooperiphyton of the Sestra River, among which larvae of chironomids (40), nematodes (24), and oligochaetes (21) have the highest species richness. The increase in the taxonomic richness of zoocenoses from the river head to its mouth is weakly expressed. The highest diversity of zoocenoses is characteristic for the contact zones of the river water with its tributaries and receiving waters. The discreteness of spatial characteristic of the taxonomic composition of zooperiphyton reflects the heterogeneity and diversity of habitat conditions of invertebrates. In regards to its effect on zoocenoses, anthropogenic pollution can exceed the impact of many environmental factors (including the current velocities) which affect the formation of rheophilic communities in river ecosystems. The dominant complexes of zooperiphyton include all trophic groups of invertebrates, among which the group of detritophages-collectors has the highest taxonomic diversity. The group of phytodetritophages-filterers + collectors mainly includes chironomid larvae of the genus Chironomus, which are associated with strongly polluted zones. Invertebrate filterers, sponges, and bryozoans prevail mainly in zooperiphyton in the lower reaches of the river, which are not subjected to the pollution.     

Spatial structure of zooperiphyton from the Ob River

Data on the qualitative and quantitative composition of zooperiphyton in the middle and lower reaches of the Ob River are reported, revealing the basic factors affecting its growth. Along most of the river, the zooperiphyton forms a continuum, which is disturbed at sites exposed to pollution. It is found that communities dominated by caddisworms prevail over most of the river; a decrease in the river stream velocity causes a change in the communities, with the replacement of Trichoptera by gastropod communities.     

Comparison of zoobenthos and zooperiphyton of large and medium rivers

The results of a study of zoobenthos and zooperiphyton of two rivers of the Ob’ River middle reaches are shown. A comparative analysis of the composition and abundance values of two ecological groups of zoobenthos and zooperiphyton hydrobionts has revealed the difference in their taxonomic compositions and dominant complexes. The similarity in total number and biomass of zoobenthos and zooperiphyton in the large river and the higher values of zooperiphyton quantitative development in a medium river have been identified.     

Study on zooperiphyton and zoobenthos of a small river

The special traits of zooperiphyton and zoobenthos structures in a small river were studied. Under conditions of maximal proximity of niches, these groups of invertebrates retain taxonomic and ecological heterogeneity. Differences in zooperiphyton and zoobenthos taxonomic structures are most pronounced in terms of presence of dipterans, oligochetes, and mollusks. In the periphyton, the dominant groups are chironomid (orthocladines, chironomines, and tanitarsines) larvae, oligochetes of fam. Naididae and mollusks of fam. Limnaeidae. In the benthos chironomid (chironomines and tanirodines), oligochetes of fam. Tubificidae, and mollusks of fam. Pisidiidae are dominant. On average, the bottom invertebrates are considerably larger than fouling organisms. At similar abundance values, the biomass of benthos is by an order of magnitude higher compared to zooperiphyton. Ranging of average biomasses of zooperiphyton and zoobenthos revealed that the leader common for both communities is the large and mobile predatory leech, Erpobdella octoculata (Linnaeus). The anthropogenic impact and zoogenic (beavers) impact upon the river biota are comparable to each other.     

Basic characteristics of zooperiphyton in large rivers of Western Siberia (Tyumen oblast)

The data on the qualitative and quantitative composition of zooperiphyton from seven large rivers of Western Siberia are presented. The species similarity of zooperiphyton has been documented in most of the rivers. The biomass in unpolluted parts is mainly formed by the larvae of caddis flies. Factors which effect the composition and structure of zooperiphyton have been determined. Changes in the structure and quantitative development of zooperiphyton are shown.     

Taxonomic and trophic structures of dominants in the zooperiphyton of waterbodies and watercourses of the upper Volga basin

All the main trophic groups of invertebrates are presented in the compositions of dominant assemblages of zooperiphyton in the studied waterbodies and watercourses. The strong pollution of water by suspended solids of anthropogenic origin in the water of the upper Volga reservoirs leads to the suppression of typically sessile filter-feeding invertebrates (sponges, bryozoans, and Dreissena) able to form the highest biomass of zooperiphyton using natural food items. The conditions of the disturbed structure of food resources are favorable for the development of detritivores-gatherers. In small rivers receiving industrial wastewaters, excessive amounts of food in the water column and in the form of sediments on the substrates suppresses invertebrates-biofowlers and facilitates the expansion of the benthic larvae of chironomids of g. Chironomus (combining the filtration and gathering of food particles on the substrates) to the vacant spatial niches. At the same time, the role of nematodes and oligochaetes with prevailing detritophages increases. In the acidified lakes of the Darwinsky National Reserve, the decrease in the total species diversity of zooperiphyton is accompanied by decreases in the role of filter-feeding invertebrates. The chironomid larvae and oligochaetes prevailed in the poor zoocenoses. The roles of predatory caddisfly larvae, black gnats, and nematodes increased. The labile structural characteristics of zooperiphyton with the conservation of the historically formed methods of foraging are the main modern way that biofouling communities adapt to changes in the quality and quantity of food resources upon modern anthropogenic pollution of the aquatic environment.     

淀山湖周丛动物群落的初步研究

作者于1991年11月至1992年11月对淀山湖水生植物上周丛动物进行了初步研究。共观察到84种周丛动物,以原生动物(38.10%)和轮虫(22.62%)占多数。按个体大小,分为小型周丛动物群落和大型周丛动物群落两种群落类型。小型周丛动物群落的优势种为似钟虫、角突臂尾轮虫等,个体数量受周丛原生动物支配,一年中有两次高峰(3-4月份和11月份),生物量在3月份最大,主要受周丛轮虫控制。大型周丛动物群落的优势种为线虫和螺类,一年只有一次数量高峰(6-8月),生物量中螺类占绝对优势(96.4%)。周丛动物在不同水生植物上的分布数量不同,沉水植物中以金鱼藻最多,大茨藻最少;并且叶上的数量明显高于茎上。漂浮植物上一般多于沉水植物,且根部最多,茎、叶相近。水生植物上周丛动物多为广布种,特有种罕见,主要出现于小型周丛动物群落中。       

Phytophilous zoocoenoses of Lake Teletskoye

The composition, structure, and spatial distribution of zoobenthos and zooperiphyton at plantfilled regions of the littoral of Lake Teletskoye have been analyzed. The dependence of the taxonomic composition, number, and biomass of zoobenthos on vegetation type has been discovered. A multilevel character of the distribution of invertebrates in macrophyte overgrowths has been shown. An analysis of the trophic structure of the communities of macroinvertebrates revealed the predominance of algodetritophagous animals in zooperiphyton. The role of plant overgrowth as a “life concentrator” in an oligotrophic lake has been revealed.     

Bacteriological aspects of pollution in the Jukskei — Crocodile river system in the Transvaal,South Africa

A combination of routine methods of bacteriological analysis has been utilised to investigate conditions in a river system which in part is subject to the effects of the discharge of appreciable quantities of sewage effluents which, during the dry season, may constitute the major part of the total flow. Other parts of the river system are free from gross pollution, and results obtained from these sections served as a basis for comparison. The river system is capable of coping with most of the detrimental effects of direct faecal pollution in varying form. But under no circumstances do these findings imply that the river system is capable of dealing with unrestricted quantities of sewage effluents for an unlimited period of time. Industrial pollution of varying character has been found to have little, if any, effect on bacterial numbers. The effect these effluents may have on the composition of the bacterial population as a whole has not been investigated, but this influence would be of local significance only. The methods used and the interpretations applied to the results seem to constitute a valuable instrument in the detailed study and assessment of bacteriological quality of the waters in a natural river system which is subject to severe pollution from sewage and industrial effluents of varying character.     

Successions of zooperiphyton in a small river

In the small Latka River, which is characterized by a high heterogeneity of abiotic characteristics and a rich fauna composition, a high diversity of developing zooperiphyton structures was recorded consisting of invertebrates with short life cycles: the larvae of chironomids, caddisflies, mayflies, oligochaetes, nematodes, and other animals. One distinctive feature of seasonal and interannual zooperiphyton succession is the annual prevalence in abundance of spreading chironomid larvae of age I, which belong to the most representative dominating group of amphibiotic invertebrates, including species adapted to different saprobic conditions. The taxonomic and quantitative domination of chironomids make it possible to consider the family Chironomidae a key group in the formation of the zoocenosis structure. Under disturbed habitat conditions (pollution, rainfall floods, and the press of omnivorous invertebrates), the restoration of typical structures occurs rather quickly due to the particular features of biology in species short life cycles. However, no relative stabilization in communities was observed. This is the main difference between the sequence of succession processes in the Latka River and that observed in large water bodies (lakes and water reservoirs), where there are no strict limitations on living-space volume or food availability and abiotic conditions are more stable, thus allowing filter-feeding sessile animals (sponges, bryozoans, and zebra mussels) to develop on solid substrates. These species are able to develop multispecies consortia and form relatively stable long-term communities.     

On the interrelation of diversity and structural and functional indicators of hydrobiont communities

Empirically derived relationships between indicators of diversity of zoobenthos, zooperiphyton, and zooplankton and the structural characteristics of communities in reservoirs of various types are presented. The relationships between indicators of diversity, the biomass of communities, the spatial structure, and the ratio of energy stored in biomass and scattered energy have been elicited.     

Hydrobiological studies on the Tugela River system

Summary A survey of pollution in the Bushmans river, and a tributary, the Little Bushmans river in the vicinity of Estcourt, Natal, is described. The pollution arose mainly from wastes discharged from a boardmill, a milk-processing factory, and a sewage-disposal, irrigation farm. The effects of these effluents on the chemistry of the river waters, and on the biological communities in them is described.The communities at polluted stations have been classified in relation to the degree of pollution, and the equivalence of the classification with the systems described by other workers has been indicated. Differences observed between communities in normal and polluted stretches of the rivers are suggested as indices of pollution.     

河流污染底泥的生态修复

通过综合近几年国内外对河流污染的治理方法,介绍了河流污染底泥的污染类型及现状,说明目前河流污染的严重性和进行修复的重要性及迫切性;阐述河流底泥生态修复的主要内容,对生态修复做了简要解释;介绍了几种目前处于试验阶段的生态修复工程技术。河流生态修复的总体目标是恢复河流系统健康,实现人与河流的和谐共存。     

微核技术监测广州灵岗河水质污染的研究

水污染已成为全球普遍关注的一个重大问题。为探讨洗水印染企业废水和生活污水排放对环境的污染程度以及对周边生物的遗传损伤,研究利用蚕豆根尖细胞微核监测技术对位于广州番禺区灵岗河段淤泥浸出液和污水引发的环境情况进行了测定。数据显示用灵岗河段污水处理后的蚕豆根尖细胞微核发生率显著大于阴性对照组的微核率,水质污染指数为2．912,初步测定该河段属中度污染。     

Composition and distribution of sponges (Porifera) in continental waters of western Siberia

The paper presents data on the composition and distribution of freshwater sponges in western Siberia. Recently, four species have been found in lakes and rivers, and one species has been recorded in a study of palynological and archaeological samples. Freshwater sponges live mainly in the small rivers and lakes of the forest-steppe and southern taiga zones. About a hundred taxa of aquatic invertebrates have been recorded together with the found sponges. The biomass of sponges among the zooperiphyton significantly decreases northwards.     

Bacterial community shift revealed Chromatiaceae and Alcaligenaceae as potential bioindicators in the receiving river due to palm oil mill effluent final discharge

A thorough outlook on the effect of palm oil mill effluent (POME) final discharge towards bacterial community dynamics in the receiving river is provided in this study by using a high-throughput MiSeq. The shift of bacterial composition could be used to determine the potential bacterial indicators to indicate contamination caused by POME. This study showed that the POME final discharge did not only alter the natural physicochemical properties of the river water but also caused the reduction of bacterial diversity in the receiving river. The Chromatiaceae and Alcaligenaceae which were not detected in the upstream but were detected in the downstream part of the river are proposed as the indicator bacteria to indicate the river water contamination caused by POME final discharge. The emergence of either one or both bacteria in the downstream part of the river were shown to be carried over by the effluent. Therefore, an accurate pollution monitoring approach using bacterial indicator is expected to complement the conventional POME pollution assessment method which is currently dependent on the physicochemical properties of the final discharge. This is the first study that reported on the potential indicator bacteria for the assessment of river water contamination caused by POME final discharge.     

ALGAL COMPETITION IN AN EPILITHIC RIVER FLORA1

Field and laboratory procedures demonstrate that the effluent from the Willimantic, Connecticut, sewage treatment plant changes the numerical composition of the dominant epilithic algae in the Shetucket River. This effect is due to the effluent altering the competitive balance between chlorella sp. and Achnanthes deflexa Reim. The chlorella completely dominates highly polluted stretches of the river, and shares dominance with A. deflexa in other areas. The degree of river pollution can be estimated by enumerating the natural standing crops of these 2 algae. A 2-membered assay utilizing these organisms is a sensitive laboratory pollution monitor and a useful predictive tool. Dominant stands of these epilithic species develop in polluted and unpolluted zones in this river due to competition for the limited area on the cobbles.     

基于“源-汇”景观的饮用水源地非点源污染风险遥感识别与评价

非点源污染因分布广泛、产生过程复杂、防治困难,近年成为影响饮用水源地水环境的重要污染源。以海南三亚赤田水库为例,开展了基于"源-汇"景观的非点源污染风险遥感识别与评价分析。首先,采用高分辨率遥感影像分类提取水源地不同类型景观分布信息;结合"源-汇"对污染的促进\\阻碍作用,在考虑影响污染物迁移的"河道距离"因子、坡度因子情况下,利用非点源污染风险指数的计算实现对区域非点源污染风险的快速识别;并基于洛伦兹曲线分析水源地景观空间分布对非点源污染的影响。结果表明:一方面,流域非点源污染风险总体较低,"汇"景观占主导作用的子流域占整个区域的76.50%;污染风险呈现东高西低的特点,极高风险区主要分布于以居住用地、建设用地等"源"景观类型为主的流域东南部区域,占整体区域面积的1.28%,而西部以林地为主污染风险小;另一方面,基于坡度因子的"源""汇"景观污染负荷之比值大于1,"源"景观在低坡度区域分布范围广,景观布局较合理;基于"河道距离"因子的"源""汇"景观污染负荷之比值为2.30,"源"景观在距河道近的区域分布范围大,对污染影响大,近河道区域需进一步调整景观格局以降低对非点源污染的影响。基于遥感与"源-汇"景观指数计算是一种快速、客观、有效的饮用水源地的非点源污染风险识别与评价方法。     

Criteria of rehabilitation of biotic communities in oil-polluted small rivers (by example of the Shava River,Nizhnii Novgorod oblast)

An assessment of the ecological state of the small Shava River (Kstovskii raion, Nizhnii Novgorod oblast) subjected to oil pollution as a result of a pipeline accident in 2007 is presented. On the basis of physical and chemical characteristics of water quality and the results of a study of hydrobiont communities, the degree of the river pollution has been determined and a conclusion about the rehabilitation of communities as a result of the complex effect of recultivation measures and self-purification processes has been made. Criteria for recultivation activity completion have been defined according to hydrobiological indicators (phytoplankton, zooplankton, and zoobenthos).