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Understanding the relationship between a dam's size and its ecological effects is important for prioritization of river restoration efforts based on dam removal. Although much is known about the effects of large storage dams, this information may not be applicable to small dams, which represent the vast majority of dams being considered for removal. To better understand how dam effects vary with size, we conducted a multidisciplinary study of the downstream effect of dams on a range of ecological characteristics including geomorphology, water chemistry, periphyton, riparian vegetation, benthic macroinvertebrates, and fish. We related dam size variables to the downstream–upstream fractional difference in measured ecological characteristics for 16 dams in the mid‐Atlantic region ranging from 0.9 to 57 m high, with hydraulic residence times (HRTs) ranging from 30 min to 1.5 years. For a range of physical attributes, larger dams had larger effects. For example, the water surface width below dams was greater below large dams. By contrast, there was no effect of dam size on sediment grain size, though the fraction of fine‐grained bed material was lower below dams independently of dam size. Larger dams tended to reduce water quality more, with decreased downstream dissolved oxygen and increased temperature. Larger dams decreased inorganic nutrients (N, P, Si), but increased particulate nutrients (N, P) in downstream reaches. Aquatic organisms tended to have greater dissimilarity in species composition below larger dams (for fish and periphyton), lower taxonomic diversity (for macroinvertebrates), and greater pollution tolerance (for periphyton and macroinvertebrates). Plants responded differently below large and small dams, with fewer invasive species below large dams, but more below small dams. Overall, these results demonstrate that larger dams have much greater impact on the ecosystem components we measured, and hence their removal has the greatest potential for restoring river ecosystems. [ABSTRACT FROM AUTHOR]

December 2017 and September 2018 by selecting five stations from Goksu Stream. In order to determine the water quality of the Goksu Stream, benthic macroinvertebrate fauna, some physicochemical parameters and biotic indices were used. pH, water temperature (C), DO (dissolved oxygen mg/L), EC (electrical conductivity uS/cm), salinity (%), depth (cm), flow rate (m/s), NH4-N (ammonium nitrogen mg/L), N02-N (nitrite nitrogen mg/L), N03-N (nitrate nitrogen mg/L, P03-P (phosphate mg/L), TP (total phosphorus mg/L), BOD (biochemical oxygen demand mg/L), TSS (total suspended solid mg/L) physicochemical parameters were measured. A number of biotic indices (Biological Monitoring Working Party-BMWP, Average Score Per Taxa-ASPT. Belgian Biotic Index-BBI) and diversity indices (Margalef, Simpson, Shannon Weaver, Simpson Evenness, Shannon Evenness). As a result of this study, a total of 35 taxa were detected. 10 taxa belong to Oligochaeta, 3 taxa belong to Gastropoda, 17 taxa belong to Insecta, 3 taxa belong to Malacos-traca, 1 taxa belong to Polychaeta and 1 taxa belong to Bivalvia. Oligochaeta (61.28 %) was determined to be the most dominant group among benthic ma-croinvertebrates. As a result of the physicochemical variables, macrozoobenthic organisms composition and applied biotic indeces, Goksu Stream has a low quality or high contaminated water quality. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Journal of Applied Ecology / Yingyong Shengtai Xuebao is the property of Chinese Journal of Applied Ecology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this study, qualitative and quantitative distributions of benthic macroinvertebrates collected monthly from Lake Büyükçekmece were investigated between June 2004 and November 2005. Five stations were selected for sediment sampling with Ekman dredge. Each sampling includes two subsamples. During sampling, some of the physico-chemical variables such as depth, water temperature, turbidity, dissolved oxygen, pH, salinity, NO2-N, NO3-N, PO4-P and total hardness were analyzed. Total of 43 taxa in 8 groups were determined. The present study showed that larval chironomids comprising 55.32% abundance of total specimens are the biggest part of benthic macroinvertebrates. It is followed by oligochates and the other group comprising 23.03% and 21.65% abundance, respectively. According to Spearman correlation analyses, relationship between the number of inviduals and some physicochemical variables such as temperature, depth and turbidity of the lake was determined statistically significant. Additionally, Jacckard and Sorenson similarity indices displayed high similarities between, station 2 and station 5 while stations 3 and 5 were found to be the most different from each other for the zoobenthic macrofauna. [ABSTRACT FROM AUTHOR]

Copyright of Review of Hydrobiology is the property of NK Yayincilik Egitim Hizmetleri and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Benthic macroinvertebrates were sampled from fifteen headwater streams, covering a gradient from five to eighty percent agricultural watershed land use/land cover (LULC), in Jersey County, Illinois. A sub-sample of invertebrates was identified to the family taxonomic level. Communities were analyzed in conjunction with LULC distributions calculated at three spatial scales: watershed, 150m stream buffer, and 50m stream buffer. Most streams exhibited similar invertebrate community composition, characterized by low diversity, an absence of pollution intolerant taxa, and a dominance of hydropsychid caddisflies and gammarid amphipods. Exceptions to this trend included three streams, which displayed communities consisting of almost all non-insectan taxa, and one stream, which had a notable population of Perlodidae (Plecoptera). Hilsenhoff's family biotic index (FBI), Shannon-Weiner diversity, and taxa richness and evenness were also calculated to assess stream degradation. None of these bioassessment metrics correlated with LULC. However, percent agriculture was significantly correlated with percent Hydropsychidae (Trichoptera) and percent Gammaridae (Amphipoda). This suggests that while agricultural development alters benthic communities in the Middle Mississippi Border natural division (MMBD) in Jersey County, the family level bioassessment metrics may either be ineffective in this region, or lack the taxonomic resolution to detect agricultural impacts in regional streams. Percent Hydropsychidae had the strongest relationship with agriculture, and may be the best metric for assessing the impacts of agricultural degradation in moderately cultivated regions of the MMBD in west central Illinois. [ABSTRACT FROM AUTHOR]

The study conducted to assess the effects ot gold mining on physico-chemical water quality and composition of benthic macroinvertebrate species in rivers located in gold mining area in the Permanent Forest Reserve Sokor Taku, Tanah Merah, Kelantan. The study was carried out at four sampling points started from the Ketubong River tributary of the Sokor River. The results of physico-chemical water quality shows that both rivers are fall within Class III, based on the National Water Quality Standard for Malaysia (NWQS). The description of Class III river is river which need extensive treatment to be use for drinking water. On the other hand, a total of 18 families and 229 individual taxa were recorded for benthic macroinvertebrate and of these, seven families belong to order ephermeroptera (caenidae, baetidae, emphemerellidae, leptopphlebiidae, heptageniidae, potamantjdae and polymitarcyidae) and dipteral (chironominae, dolichopodidae, ceratopogonidea and empididae), 2 families to tnchopteran (hydropsychidae and philopotamidae) and one family to coleopterafi (elmidae) and lumbnculida (lumbriculidae). There were three sensitive taxa namely ephermeroptera, plecoptera and trichoptera (EPT) present in Sokor River (Point 1) and (Point 2) to indicate an excellent river health but only one sensitive taxa present in Ketubong River(Point of Reference) and Sokor River (Point 3 ) namely plecoptera and trichoptera respectively. At the same time, Sokor River(Point 2) also recorded the highest density of benthic macroinvertebrate which is 300 individual/m2 and the lowest was recorded at Ketubong River (Point of Reference)which is 144 individual/m2. Based on the results it could be suggested that, the operational of Sokor gold mining does not give significant impact to the Sokor River. [ABSTRACT FROM AUTHOR]

Copyright of Review of Hydrobiology is the property of NK Yayincilik Egitim Hizmetleri and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Benthic macroinvertebrates can accumulate pollutants such as heavy metals from water and sediment of a river. These studies aims to identify the differences in concentration of Cd, Zn, Cu, and Fe in Paragyractis sp. (Insecta: Lepidoptera) and Hydropsyche sp. (Insecta: Trichoptera) that live in Kreo River, before and after the Jatibarang landfill leachate discharge. Another aim was to find out the differences of these metals bioaccumulation factor of two benthic from its environment. To obtain the aims, benthic samples were collected at four stations on the Kreo River. The first station located next to ±150 m upstream from the point of discharge of leachate. The second, third, and fourth station respectively to be about 1, 500, and 3000 m downstream from the point. All the samples were analyzed by HACH DREL 2000 spectrophotometer in order to determine the total amounts of Cd, Zn, Cu, and Fe. Bioaccumulation factors (BAF) calculated based on the ratio between heavy metal content in benthic with the metals concentration from their environment. The results showed that the landfill leachate quite a role in increasing the concentrations of heavy metals (except Cu) in Hydropsyche sp., but did not cause increased in Paragyractis sp. Both benthic BAF showed a similar pattern based on the type of environment phase. Metals BAF of Hydropsyche sp. and Paragyractis sp. from water that is sorted from highest to lowest as follows: Cu > Zn > Fe > Cd, while the sediment is: Zn > Cu > Cd > Fe. [ABSTRACT FROM AUTHOR]

Copyright of Biota Neotropica is the property of Biota Neotropica and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The article presents a study that aims to demonstrate the consequences of urbanization and urban stream restoration on both the physical and biological structure of the stream ecosystem. It is found out that restoration has failed to enhance habitat over afflicted urban channels which implicate that watershed level hydrologic processes disgrace restoration efforts. It concludes that by expanding urban restoration will lead to better restoration design and will result positive outcomes.

1. This study was conducted at Kelkit Stream and its tributaries in June 2009. Kelkit Stream is located in the north-eastern of Turkey and it’s the biggest tributary ofYeşilırmak River.2. Benthic macro invertebrate samples were taking from eight sites. They were identified to genus level. Habitat preferences and stream zonation preferences of benthic macro invertebrate genera were also given.3. Cluster analysis, which is one of the most preferred classification methods, wasapplied to benthic macro invertebrate fauna and sites. Habitat and stream zonation preferences of the genera which was contained in groups and subgroups that were formed as a result of the analysis were compared. Also, dominant taxa at collecting sites were given.4. According to the result of the study, habitat quality of Kelkit Stream and its tributaries showed deteriorations at some sites. If these deteriorations continue in the future, there will be an inevitable decrease in the habitat quality of Kelkit Stream and its tributaries. [ABSTRACT FROM AUTHOR]

The present paper approaches the relationship between the semi-intensive carp growing fishing management and the diversity of the benthic invertebrate aquatic fauna. In order to do this, there has been set a program to collect bent quantitative samples every two months during the intensive fodder feeding of the fish (April - October 2009). Sample processing and data analysis showed that this type of management causes tremendous transformations in the structure and dynamics of the community. Moreover, the water physical-chemical factors are also affected, especially the being much higher in the ponds than in the canal systems which help bring the water into the ponds. The quantity of organic substances in the water and in the deposits, resulting from the fishing management activities, is reflected very clearly in the composition and dynamics of the macrozoobenthic communities. This organic substance is processed by the benthic community, generally by oligochaetes and particularly by chironomids. These results clearly indicate the importance of maintaining the macrozoobentos fauna in fish farms sediments to enhance decomposition of organic wastes. [ABSTRACT FROM AUTHOR]

Copyright of Review of Hydrobiology is the property of NK Yayincilik Egitim Hizmetleri and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract: In this study, we assessed importance of sediment-associated trace metals in structuring benthic macroinfaunal assemblages along multiple environmental gradients in chronically polluted salt marshes of the Arthur Kill – AK (New York, USA). More than 90% of benthic macroinfaunal communities at the northern AK sites consisted of a considerably large number of only a few polychaete and oligochaete species. Approximately 70% of among-site variances in abundance and biomass of benthic macroinfaunal communities was strongly associated with a few environmental variables; only sediment-associated mercury consistently contributed to a significant proportion of the explained variances in species composition along natural environmental gradients (e.g., salinity). Although sediment-associated copper, lead, and zinc were substantially elevated at some of the AK sites, their ecological impacts on benthic macroinfaunal communities appeared to be negligible. These findings suggest that cumulative metal-specific impacts may have played an important role in structuring benthic macroinfaunal communities in chronically polluted AK ecosystems. [Copyright &y& Elsevier]

Water eutrophication is a global problem,and one of the major environmental problems in China. At present,its studies in China are mainly focused on lakes and reservoirs,whereas a few on rivers. Based on the stress-response of benthic macroinvertebrate assemblages to water nutrients,we used the nonparametric deviance reduction(change point analysis)to compute the breakpoints of nutrients concentrations,in the upper reaches of Xitiao Stream in Zhejiang. The results indicated that the breakpoints of total nitrogen (TN) and total phosphors (TP)were 1.409 mg·L-1 and 0.033-0.035 mg·L-1, respectively. The TN and TP concentrations at reference sites were lower, while those at urban sewage-polluted sites were higher than the thresholds. In latter case, a serious degradation of benthic macroinvertebrates assemblages could be induced. To establish water nutrients criteria with relation to aquatic organisms would make the biological monitoring play a full role in water management, and provide scientific data to estimate the total maximum daily load(TMDL) of TN and TP in water body. [ABSTRACT FROM AUTHOR]

Seasonal changes of proportional distribution, biotic indices, abundance, and frequency of benthic macroinvertebrate communities in Menderes Creek were investigated at 5 stations between November 2005 and July 2006. The fauna included a total of 87 taxa belonging principally to Insecta (52 taxa, especially Chironomidae), Oligochaeta (12 taxa), Mollusca (11 taxa), Hirudinae (7 taxa), and Malacostraca (5 taxa). Mean density was estimated to be 778 individuals m-2 for the 87 taxa. Mollusca (38.5%) and Insecta (39.9%) are the dominant groups among the macroinvertebrate assemblages. Average Shannon-Wiener diversity index was calculated as 1.41, average Margalefs richness index was 1.27, and average Pielou index was 0.61. The results of one-way analysis of similarity (ANOSIM) indicated that macroinvertebrate compositions were significantly different between sampling sites (p< 0.05). ANOSIM and similarity percentage analysis (SIMPER) revealed significant differences and a high degree of community dissimilarity within and between the sampling stations. [ABSTRACT FROM AUTHOR]

The article discusses the study on the response patterns of the community in evaluating benthic invertebrate composition in metal-polluted streams. The questions with respect to how ecosystems and their assemblages respond to anthropogenic stressors have been of general interest. The authors asked whether assemblage composition among stream sites becomes more similar after exposure to a common stressor. They compare benthic invertebrate similarity and assemblage composition among sites having different levels of heavy-metal pollution. Low community similarity in the medium and high-metal categories suggests that accurate prediction of assemblage composition at impacted sites may be challenging.

Modified composite biochar offers a cost-effective solution for the remediation of contaminated sediments; however, few studies have evaluated the effects of modified composite biochar amendment on the ecotoxicity of contaminated sediment based on benthic macroinvertebrates. A 21-day sediment toxicity test was conducted using the freshwater snail Bellamya aeruginosa to examine the intrinsic ecotoxicity of a novel KOH-modified composite biochar (KOH-CBC) and its efficacy for reducing the bioavailability, uptake, and ecotoxicity of perfluorooctanoic acid (PFOA). It was found that KOH-CBC is toxic to B. aeruginosa , which may be attributed to its high polycyclic aromatic hydrocarbons (PAHs) content and alkalinity. The addition of KOH-CBC to PFOA-contaminated sediments can markedly reduce the bioavailability and uptake of PFOA by more than 90% and 50%, respectively, and subsequently alleviate the toxicity of PFOA to B. aeruginosa by at least 30%. Increasing the KOH-CBC dosage is not beneficial for further mitigating the toxicity of PFOA-contaminated sediments. Our findings imply that KOH-CBC is a promising sorbent for the in-situ remediation of PFOA-contaminated sediments. Application of acidified KOH-CBC at a dosage of approximately 1–3% will be sufficient to control the ecotoxicity of PFOA; however, its long-term environmental effects should be further validated. [Display omitted] • KOH-CBC is toxic to Bellamya aeruginosa due to its high PAHs content and alkalinity. • KOH-CBC could considerably reduce the bioavailability and uptake of PFOA in sediment. • KOH-CBC could alleviate the toxicity of PFOA to B. aeruginosa by at least 30%. • Acidified KOH-CBC at 1–3% will be sufficient to control PFOA ecotoxicity in sediment. [ABSTRACT FROM AUTHOR]

Our understanding of how forest management practices affect the relative importance of autochthonous vs. allochthonous resource use by headwater stream food webs is relatively poor. To address this, we used stable isotope (C, N, and H) analyses of food sources and macroinvertebrates from 15 streams in New Brunswick (Canada) and assessed how different catchment conditions arising from the gradient in forest management intensity affect the contribution of autochthonous resources to these food webs. Aquatic primary production contributed substantially to the biomass of invertebrates in these headwater streams, especially for scrapers and collector‐gatherers (25–75%). However, the contribution of algae to food webs decreased as forest management intensity (road density and associated sediments, water cations/carbon, and dissolved organic matter humification) increased, and as canopy openness decreased. This trend was probably due to an increase in the delivery of organic and inorganic terrestrial materials (dissolved and in suspension) in areas of greater harvesting intensity and road density, which resulted in more heterotrophic biofilms. Overall, results suggest that, despite the presence of riparian buffers, forest management can affect stream food web structure via changes in energy flows, and that increased protection should be directed at minimizing ground disturbance in areas with direct hydrological connection to streams and at reducing dissolved and particulate matter inputs from roads and stream crossings in catchments with high degrees of management activity. [ABSTRACT FROM AUTHOR]

Biological criteria were developed to assess water quality in mesohaline and polyhaline estuarine waters in North Carolina. The criteria used a combination of three metrics: a new `Hilsenhoff-type' biotic index incorporating the sensitivity to pollution of each taxon and itsrelative abundance, total number of taxa, and number of amphipod andcaridean shrimp taxa. Agreement with an independent data set was 90%, as was within site repeatability of this biocriteria over a range of water qualities and salinities. The versatility of the biotic indexis discussed relative to other sampling methods and in other parts of the world. [ABSTRACT FROM AUTHOR]

Of the approximately 140 non-indigenous species that have invaded the Great Lakes since the early 1800s, few have had greater effects on this ecosystem than the zebra and quagga mussel (Dreissena polymorphaand D. bugensis, respectively). In this study the effects of these bivalves on macroinvertebrates inhabiting hard substrates in western Lake Erie were quantified. Biomass, densities, diversity of macroinvertebrates, and particulate organic matter mass were measured on brickswith high and low Dreissena densities that were held at a depth of 3.5 m for 49 days in 1996. Total macroinvertebrate densities and biomass (excluding Dreissena) were two and five times greater on substrates with high Dreissena densities than when Dreissena were rare. These differences were largely attributed to the amphipod Echinogammarus ischnus, itself an invading species, which constituted 29 and 31% of total macroinvertebrate densities and biomass, respectively, on Dreissena-dominated substrates. Dreissena also stimulated increased macroinvertebrate diversity, causing a shift from a community dominated by the chironomid Dicrotendipes neomodestus to an assemblage characterizedby increased densities and equitability of hydroids (Hydridae), the flatworm Dugesia tigrina, tubificid oligochaetes, leeches (Alboglossiphonia heteroclita and immature Erpobdellidae), limpets (Ancylidae), snails (Physella integra and Amnicola limosa), Echinogammarus, the microcaddisfly Hydroptila ?waubesiana, and the chironomid Microtendipespedellus. No taxon responded negatively to Dreissena in this study. In addition, particulate organic matter mass, an important food and habitat resource for benthic invertebrates, was two times greater on Dreissena-dominated substrates than on bricks with few Dreissena. Our results support hypotheses that Dreissena have strong effects on community dynamics and energy flow pathways in the Great Lakes. [ABSTRACT FROM AUTHOR]

The Oak Ridges Moraine is a prominent physiographic feature of southern Ontario that functions as the source area for many streams. It has been the focus of increased attention recently because of concern about its protection in the face of rapid urban growth in the Greater Toronto Area. In 1992, we undertook a survey of 28 sites from relatively undisturbed streams of the Oak Ridges Moraine; prior to our work,these regional-scale data were lacking. Our survey comprised the collection of physical, chemical, and biological data, with emphasis on rapid bioassessment of benthic macroinvertebrate communities. The sites sampled were small, cold, well-oxygenated, spring-fed, headwater streams that supported diverse assemblages of benthic macroinvertebrates, including a number of sensitive taxa. At most sites, water quality was better than the water quality standards normally applied to surface waters. Differences among sites in water temperature, total taxon richness, and the concentrations of key chemical variables may reflect varying degrees of influence from springs. We used the approach of Novak and Bode (1992) to develop an Oak Ridges Moraine community model as a tool for evaluating observed stream conditions based on the composition of the benthic macroinvertebrate communities from the 28 reference sites. This characterization of reference conditions provides regional context for evaluating information related to headwater streams of the Oak Ridges Moraine. [ABSTRACT FROM AUTHOR]

Guidance concerning recommended storage times for sediments to be used in toxicity tests generally has not been based upon systematicallycollected experimental data. The objective of this study was to better define the effects of storage time on toxicity of a series of freshwater sediments. Sixteen sediments with varying types of contaminants were collected, homogenized and stored at 4 deg. C in 1 liter aliquots, which were periodically tested for toxicity to the amphipod Hyalella azteca and the midge Chironomus tentans after storage times of up to 101 weeks. The sediments ranged from non-toxic to extremely toxic (100% mortality) in 10-day assays, with several of the samples displaying an intermediate degree of toxicity (e.g. partial mortality, reduced growth). Biological responses in most of the samples did not vary with time relative to their statistical relationship to control values; samples identified initially as toxic (or non-toxic) tended to remain toxic (or non-toxic) regardless of when they were tested. The variations that were observed in biological responses over time generally were not systematic; that is, there were no apparent trends in samples becoming more (or less) toxic in the 10-day assays. This suggests that the source of at least some of the temporal changes in toxicity were due to inherent biological variability of the assays used toassess the sediments, rather than the effects of storage. In C. tentans tests with the least toxic sediments, among-replicate variabilitytended to be greater in initial assays than in tests with samples that had been stored for some period of time. This may have been due tothe presence of indigenous competitive or predatory organisms that did not survive during prolonged storage. [ABSTRACT FROM AUTHOR]