Sample records for benthic macroinvertebrate assemblages

  1. Fish stomach contents in benthic macroinvertebrate assemblage assessments

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    TH. Tupinambás

    Full Text Available The choice of sampling gears to assess benthic macroinvertebrate communities depends on environmental characteristics, study objectives, and cost effectiveness. Because of the high foraging capacity and diverse habitats and behaviors of benthophagous fishes, their stomach contents may offer a useful sampling tool in studies of benthic macroinvertebrates, especially in large, deep, fast rivers that are difficult to sample with traditional sediment sampling gear. Our objective was to compare the benthic macroinvertebrate communities sampled from sediments with those sampled from fish stomachs. We collected benthic macroinvertebrates and fish from three different habitat types (backwater, beach, riffle in the wet season, drying season, and dry season along a single reach of the Grande River (Paraná River Basin, southeast Brazil. We sampled sediments through use of a Petersen dredge (total of 216 grabs and used gill nets to sample fish (total of 36 samples. We analyzed the stomach contents of three commonly occurring benthophagous fish species (Eigenmannia virescens, Iheringichthys labrosus, Leporinus amblyrhynchus. Chironomids dominated in both sampling methods. Macroinvertebrate taxonomic composition and abundances from fish stomachs differed from those from sediment samples, but less so from riffles than from backwater and beach habitats. Macroinvertebrate taxa from E. virescens stomachs were more strongly correlated with sediment samples from all three habitats than were those from the other two species. The species accumulation curves and higher mean dispersion values, compared with with sediment samples suggest that E. virescens is more efficient than sediment samples and the other fish studied at collecting benthic taxa. We conclude that by analyzing the stomach contents of benthophagous fishes it is possible to assess important characteristics of benthic communities (dispersion, taxonomic composition and diversity. This is especially true

  2. Conservation unit and water quality: the influence of environmental integrity on benthic macroinvertebrate assemblages

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    Jessé Renan Scapini Sobczak


    Full Text Available AIM: This study aimed to determine the effectiveness of a Conservation Unit (CU in maintaining the quality of freshwater habitats and to evaluate the influence of environmental integrity on benthic macroinvertebrate assemblages. METHODS: The research was conducted at sampling sites located within and outside of the CU in the Alto Uruguai region, southern Brazil, and included two stages: (i the collection of benthic macroinvertebrates and (ii the application of a Rapid Assessment Protocol (RAP to characterise the habitat quality. RESULTS: A total of 1,362 benthic macroinvertebrates were collected during the study, totalling 30 taxa. The densities within and outside the CU were significantly different (F= 160.08; p= 0.05, and the Shannon diversity and taxa richness followed the same pattern (F= 118.72, p= 0.05; and F= 176.33, p= 0.04, respectively. In contrast, the Pielou equitability did not differ within and outside the CU (F= 0.19, p= 0.74. The biotic index (Biological Monitoring Working Party indicated that water quality was good or very good in the majority of cases. Most of the sampling sites were classified as ‘natural’ according to the RAP. The taxa richness was significantly related to habitat diversity (F= 7.24; p = 0.05, but no significant relationship was found between the habitat diversity and the Shannon diversity (F= 2.13, p = 0.22. CONCLUSION: The CU was effective for the conservation of water quality and the freshwater biodiversity of benthic macroinvertebrates. The results show that the environmental integrity was related to the distribution of benthic macroinvertebrates, primarily to the taxa richness. More detailed investigations need to be developed to better understand these relationships and to take into account the temporal scale. An analysis of the most significant sources of stress on the aquatic life outside the area is recommended.

  3. Effects of anthropogenic impacts on benthic macroinvertebrates assemblages in subtropical mountain streams

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    Leticia M. Mesa


    Full Text Available The nature of the riparian and surrounding landscape has been modified by anthropogenic activities, which may subsequently alter the composition and functional structure of macroinvertebrate assemblages. The effect of these changes on function of benthic fauna is difficult to assess due to the scarce knowledge on functional structures in tropical streams. In this study we evaluate whether sites impacted and unimpacted by anthropogenic alterations differed in assemblage composition and density, richness and diversity of each functional feeding group. The selection of the sites was related to their distinct riparian characteristics, following the QBRy riparian quality index. Collector-gatherer was the dominant functional feeding group, comprising 91% of total density, whereas the proportion of shredders was very low, representing less of 0.5% of total density. Asemblage composition of macroinvertebrates differed between impacted and unimpacted sites. Predators were dominant in taxa number, representing about 60% of total taxa richness. In addition, the diversity and richness of collector-gatherers differed significantly between degraded and unimpacted sites, reflecting the sensitivity of this group to environmental changes and the utility to be used in the assessment of anthropogenic modifications. The results of this study reinforce the idea that riparian corridor management is critical for the distribution of macroinvertebrate assemblages as well as functional organization of lotic streams.

  4. Temporal and altitudinal variations in benthic macroinvertebrate assemblages in an Andean river basin of Argentina

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    Erica E. Scheibler


    Full Text Available Environmental variables and benthic macroinvertebrate assemblages were spatially and seasonally examined over two consecutive years (2000-2002 along a glacier and snowmelt river in the central-west of Argentina where lies the highest peak in America, Mount Aconcagua (6956 m elevation. The goal was to assess seasonal and altitudinal variability in benthic community structure and to define whether physical-chemical variables affect distribution of aquatic insects. The Mendoza river basin was characterised by high variability in flow and transparency, high conductivity, hard calcium sulphate water, neutral and alkaline pH, and dominant substrate composed of small blocks, cobbles, pebbles, and sand-silt. Richness of invertebrates was low, with the lowest taxonomic richness being recorded at the mouth. The dominant group with highest taxonomic richness was Diptera, although caddisflies, mayflies, beetles, and stoneflies were present. Seasonal and spatial variations in biotic and abiotic variables were detected. Maximal densities and taxonomic richness were recorded in autumn and winter. From Modified Morisita’s Cluster analysis it was found that the system is divided into two groupings of sites related to each other by faunal composition. INDVAL revealed species turnover along the altitudinal gradient of some taxa: Andesiops, Massartellopsis, Edwarsina, Chelifera, and Ceratopogonidae had preference for the headwaters (2835-2425 m elevation, Smicridea murina and Baetodes for the lower section (1413-1085 m elevation, and Austrelmis for the middle and lower sections. The middle section (1846-1727 m elevation was a transition area where taxa from the headwaters and the lower section coexisted. Generalised Linear Models evidenced that altitude was the major factor determining macroinvertebrate assemblages along the large arid Mendoza River and that the physical-chemical variables that most influenced variation in community structure were: transparency

  5. Influence of agricultural land-use and pesticides on benthic macroinvertebrate assemblages in an agricultural river basin in southeast Brazil. (United States)

    Egler, M; Buss, D F; Moreira, J C; Baptista, D F


    Land-use alterations and pesticide run-offs are among the main causes for impairment in agricultural areas. We evaluated the influence of different land-uses (forest, pasture and intensive agriculture) on the water quality and on benthic macroinvertebrate assemblages on three occasions: in the dry season, wet season and at the end of the wet season. Macroinvertebrates responded to this gradient of impairment: agricultural sites had significantly lower richness numbers than forested and pasture sites, and all major invertebrate groups were significantly affected. Most taxa found in forested sites were found in pasture sites, but often with lower densities. In this case, the loss of habitats due to sedimentation and the lower complexity of substrates seem to be the disruptive force for the macroinvertebrate fauna.

  6. Oyster reef restoration in the Northern Gulf of Mexico: effect of artificial substrate and sge on nekton and benthic macroinvertebrate assemblage use (United States)

    Brown, Laura A.; Furlong, Jessica N.; Brown, Kenneth M.; LaPeyre, Megan K.


    In the northern Gulf of Mexico (GOM), reefs built by eastern oysters, Crassostrea virginica, provide critical habitat within shallow estuaries, and recent efforts have focused on restoring reefs to benefit nekton and benthic macroinvertebrates. We compared nekton and benthic macroinvertebrate assemblages at historic, newly created (6years) shell and rock substrate reefs. Using crab traps, gill-nets, otter trawls, cast nets, and benthic macroinvertebrate collectors, 20 shallow reefs (oyster structure for benthic macroinvertebrates compared to bare bottom, we tested preferences of juvenile crabs across depth and refuge complexity in the presence and absence of adult blue crabs (Callinectes sapidus). Juveniles were more likely to use deep water with predators present only when provided oyster structure. Provision of structural material to support and sustain development of benthic and mobile reef communities may be the most important factor in determining reef value to these assemblages, with biophysical characteristics related to reef location influencing assemblage patterns in areas with structure; if so, appropriately locating created reefs is critical.

  7. Structure of benthic macroinvertebrate assemblages on a gradient of environmental integrity in Neotropical streams

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    Marcia Thais Suriano


    Full Text Available AIM: This study investigated the taxonomic composition of the benthic macroinvertebrates in streams to evaluate how this fauna reflects the various uses of the soil and to identify which groups of macroinvertebrates might be taken as characterizing each situation under study. METHODS: To achieve these objectives, 29 streams were collected and inserted in regions with different conservation using Surber sampler. Analyzes were performed of environmental variables (Principal Components Analysis - PCA and taxonomic structure of the community (taxon richness, numerical abundance and Multidimensional scaling - MDS. RESULTS: EPT group (orders Ephemeroptera, Plecoptera and Trichoptera and the Coleoptera exhibited greater numerical abundance and taxon richness in streams located in reference areas. In contrast, dipteran larvae, especially the chironomids, along with immature odonates, were more abundant in streams in areas suffering from a lack of riparian forest. Multidimensional scaling analysis (MDS revealed an environmental gradient, on which the streams within the Atlantic forest formed a tightly clustered group, as did those in semideciduous forests. However, the latter group occupied an intermediate position between the Atlantic forest streams and those in areas disturbed by human activity. Among these areas there were no specific clusters by monoculture. CONCLUSIONS: Among the groups of streams defined by the types of land use in the adjacent areas, the state of integrity was found to decline from Atlantic rainforest, through semi-deciduous forest and then pasture, to the monocultures of eucalypts and sugarcane.

  8. Evaluation of benthic macroinvertebrate assemblage for disturbance zonation in urban rivers using multivariate analysis: Implications for river management

    Indian Academy of Sciences (India)

    Ram Devi Tachamo Shah; Deep Narayan Shah


    River pollution has tremendously increased in the major cities of South Asia, where the rivers have become a repository for domestic, agricultural, municipal and industrial wastes. This study presents the evaluation of benthic macroinvertebrate assemblage as a means of assessing ecological status, determining different disturbance zones and identifying environmental variables and stressors that deteriorate the river ecosystem. In total, 20 sites in 36-km stretch of the main stem of the Bagmati River and 7 sites on its tributaries were selected for sampling in the post-monsoon and pre-monsoon seasons during the time period 2008–2010. The Ganga River System Biotic Score (GRSbios) index was applied to determine the ecological status. The ecological status of the different Bagmati River stretches ranged from reference, class 1 to class 5 (extremely polluted). We identified three types of disturbance zones along the river, ranging from minimally polluted to extremely polluted. A river corridor survey was conducted to identify any river stressing factors, revealing a sharp deterioration of the river from upstream to downstream with increasing concentrations of chloride and ortho-phosphate phosphorus. Effluents and Activities and Facilities were found to be the major stressing factors to the river ecosystem. The information gained should help water managers find the most time-efficient and cost-effective measures to address river degradation.

  9. Temporal variability in discharge and benthic macroinvertebrate assemblages in a tropical glacier-fed stream

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    Jacobsen, Dean; Andino, Patricio; Calvez, Roger;


    Abstract High flows are major disturbances in streams and cause benthic communities to vary temporally. Meltwater runoff in glacier-fed streams at temperate–arctic latitudes primarily follows a strong seasonal pattern. In contrast, such streams at the equator show less seasonal, but more-pronounc......Abstract High flows are major disturbances in streams and cause benthic communities to vary temporally. Meltwater runoff in glacier-fed streams at temperate–arctic latitudes primarily follows a strong seasonal pattern. In contrast, such streams at the equator show less seasonal, but more......-pronounced diel variability in discharge that tracks a year-round diurnal melting–nocturnal freezing cycle of glaciers. Consequently, qualitative and quantitative differences in temporal variability of macrobenthos communities should be expected between high-latitude and tropical glacier-fed streams. We explored...... and sampled fauna at approximately quarterly intervals over 30 mo. Temporal variability in the fauna was aseasonal. However, the overall magnitude of the coefficient of variability (CV) at the 3 sites was not lower than the CV at temperate latitudes. The explanatory power of flow did not differ among...

  10. The assemblage characteristics of benthic macroinvertebrates in the Yalutsangpo River, the highest major river in the world (United States)

    Xu, Mengzhen; Wang, Zhaoyin; Pan, Baozhu; Yu, Guoan


    Aquatic ecosystems of highland rivers are different from those of low altitude rivers because of the specific topography and environmental parameters associated with high altitudes. Yalutsangpo, the upper course of the Brahmaputra River, is the highest major river in the world, flowing from west to east across Tibet, China and pouring into India. Macroinvertebrates were sampled from Yalutsangpo and its tributaries, the Lhasa, Niyang, and Parlong Tsangpo Rivers, from October 2009 to June 2010, to study characters of the highland aquatic ecosystem. Altogether, 110 macroinvertebrate taxa belonging to 57 families and 102 genera were identified from the basin. The biodiversity and composition of macroinvertebrate assemblages were strongly affected by altitude gradients. Local diversity represented by taxa richness and the improved Shannon-Wiener index were high at altitudes of 3,300-3,700 m, among which suitability of habitat was higher due to the better integrated environmental conditions of water temperature, dissolved oxygen, and aquatic vegetation, etc. Macroinvertebrates were grouped into shredders, scrapers, predators, collector-filterers, and collector-gatherers according to their feeding behaviors. It was found that the distributions of the functional feeding groups varied with habitat altitudes. Shredders were present at altitudes of 2,900-4,400 m, while scrapers mainly inhabited altitudes of 3,500-4,500 m, and collector-filterers preferred 3,500-4,000 m. Even though the local taxa richness was not high at each site, the taxonomic composition and density of the assemblages varied greatly among the different sites, resulting in much higher regional diversity compared to the lowland river with similar flow and substrate conditions. The regional cumulative taxa richness of Yalutsangpo decreased and more families were lost as the altitude increased. However, some families that were newly present as the altitude increased were essential for sustaining the high


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    Zdeněk Adámek


    Full Text Available The lower Morava and Dyje rivers belong among the large lowland rivers on the southeast of the Czech Republic flowing into the Danube 69 km downstream of their confluence. Despite their high nature value and environment protection, both rivers suffered from heavy pollution from the sixties to the eighties of the last century. Significant improvement of their water quality during the last two decades resulted in the partial recovery of former assemblages of both benthic macroinvertebrates and fish. Recently, altogether 262 and 137 taxa of macrozoobenthos were recorded at the Dyje and Morava rivers, respectively. In the River Dyje, 3 and 21 non-native and threatened (according to IUCN categories invertebrate species, respectively, were ascertained, whilst in the River Morava their numbers were 2 and 10, respectively. The fish assemblage consisted of 23 and 24 species, respectively, plus one hybrid in each of the rivers, bleak being by far the most abundant fish. In the sections under study, several rare and/or protected species were also recorded. Two of them, ide (Leuciscus idus and burbot (Lota lota belong among vulnerable fish species and four others, white-eye bream (Abramis sapa, striped ruffe (Gymnocephalus schraetser, streber (Zingel streber and zingel (Zingel zingel, are considered as critically endangered species. Currently, both lower stretches of the rivers Morava and Dyje have been heavily invaded by round goby, Neogobius melanostomus.

  12. Benthic Macroinvertebrate Communities in Agriculturally Impaired Streams

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    Virginija Pliuraite


    Full Text Available Normal 0 false false false EN-US X-NONE X-NONE This work presents research into the taxonomic composition of macroinvertebrate communities in streams that are under the influence of agricultural pollution A total of 67 macroinvertebrate taxa (including 61 identified species belonging to 40 families have been identified in the explored streams. The greatest species richness is recorded for the Trichoptera (18 species/1 taxa and Mollusca (12 species. The molluscs Gyraulus albus, amphipods Gammarus pulex, caddisflies Hydropsyche pellucidula and oligochaetes are detected in all examined streams. There, the number of total benthic macroinvertebrate taxa is highly variable, ranging from 16 to 40. Results show that the examined streams depending on the benthic macroinvertebrate taxonomic composition and predominance of seperate macroinvertebrate groups undergo different pollution. Intolerant to pollution taxa such as Plecoptera, which are the most sensitive to pollution insects, have been found only in 5 of 12 examined streams and in low abundances. The richness and diversity of macrozoobenthos in some streams appear to respond to the water quality deterioration. The present study has found out that in the stream where the total macroinvertebrate taxa, EPT taxa richness are the lowest and a relative abundance of gatherers is the highest, the values of NH4-N, NO3-N, total N, PO4-P and total P in the stream water are the highest, too.

  13. Benthic macroinvertebrates in Italian rice fields

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    Daniela Lupi


    Full Text Available Rice fields can be considered man-managed temporary wetlands. Five rice fields handled with different management strategies, their adjacent channels, and a spring were analysed by their benthic macroinvertebrate community to i evaluate the role of rice agroe- cosystem in biodiversity conservation; ii find indicator species which can be used to compare the ecological status of natural wetlands with rice agroecosystems; and iii find the influence of environmental variables on biodiversity. Different methods of data analysis with increasing degree of complexity – from diversity index up to sophisticated multivariate analysis – were used. The investigation provided a picture of benthic macroinvertebrates inhabiting rice agroecosystems where 173 taxa were identified, 89 of which detected in rice paddies. Among them, 4 phyla (Mollusca, Annelida, Nematomorpha, and Arthropoda, 8 classes (Bivalvia, Gastropoda, Oligochaeta, Hirudinea, Gordioida, Insecta, Branchiopoda, and Malacostraca, 24 orders, 68 families, 127 genera and 159 species have been found. Ten threatened and 3 invasive species were detected in the habitats examined. The information obtained by the different methods of data analysis allowed a more comprehensive view on the value of the components of rice agroecosystems. Data analyses highlighted significant differences between habitats (feeding channel and rice field, with higher diversity observed in channels, and emphasised the role of the water chemical-physical parameters. The period of water permanence in rice fields resulted to be only one of the factors influencing the community of benthic macroinvertebrates. The presence of rare/endangered species allowed characterising some stations, but it was less informative about management strategies in rice paddies because most of these species were absent in rice fields.

  14. Bioassessment of Choghakhor Wetland using Benthic Macroinvertebrates

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    P. Fathi


    Full Text Available In present study, besides investigating benthic communities and their demographics in Choghakhor wetland, the water quality has been evaluated and classified. Then, 10 stations were selected and sampling of benthos was done every 45 days since April 2010 to March 2011, with 3 replications at each station. Samples were obtained by Ekman grab Sampler (surface 400 cm2. The collected samples were separated and fixed by formalin (4%. The Macroinvertebrates samples were identified and counted in laboratory. Generally 25 families of benthic macroinvertebrates belonging to 5 classes and 12 orders were identified. The results were calculated as community measures, including total richness, Shannon - Wiener diversity index and Hilsenhoff Biological index at family level. The results obtained from temporal and spatial changes of data (Statgeraphics software and water qualitative classification using Shannon diversity index conformed to biological Hilsenhoff index. And finally, water quality of wetland was assessed to be polluted in average to high level. According to this study findings, it seems that, these indicators could be used as useful tools for evaluating water supplies quality.

  15. Evaluation of Environmental Factors to Determine the Distribution of Functional Feeding Groups of Benthic Macroinvertebrates Using an Artificial Neural Network

    NARCIS (Netherlands)

    Verdonschot, P.F.M.


    Functional feeding groups (FFGs) of benthic macroinvertebrates are guilds of invertebrate taxa that obtain food in similar ways, regardless of their taxonomic affinities. They can represent a heterogeneous assemblage of benthic fauna and may indicate disturbances of their habitats. The proportion of

  16. Hydrologic controls on basin-scale distribution of benthic macroinvertebrates (United States)

    Bertuzzo, E.; Ceola, S.; Singer, G. A.; Battin, T. J.; Montanari, A.; Rinaldo, A.


    The presentation deals with the role of streamflow variability on basin-scale distributions of benthic macroinvertebrates. Specifically, we present a probabilistic analysis of the impacts of the variability along the river network of relevant hydraulic variables on the density of benthic macroinvertebrate species. The relevance of this work is based on the implications of the predictability of macroinvertebrate patterns within a catchment on fluvial ecosystem health, being macroinvertebrates commonly used as sensitive indicators, and on the effects of anthropogenic activity. The analytical tools presented here outline a novel procedure of general nature aiming at a spatially-explicit quantitative assessment of how near-bed flow variability affects benthic macroinvertebrate abundance. Moving from the analytical characterization of the at-a-site probability distribution functions (pdfs) of streamflow and bottom shear stress, a spatial extension to a whole river network is performed aiming at the definition of spatial maps of streamflow and bottom shear stress. Then, bottom shear stress pdf, coupled with habitat suitability curves (e.g., empirical relations between species density and bottom shear stress) derived from field studies are used to produce maps of macroinvertebrate suitability to shear stress conditions. Thus, moving from measured hydrologic conditions, possible effects of river streamflow alterations on macroinvertebrate densities may be fairly assessed. We apply this framework to an Austrian river network, used as benchmark for the analysis, for which rainfall and streamflow time-series and river network hydraulic properties and macroinvertebrate density data are available. A comparison between observed vs "modeled" species' density in three locations along the examined river network is also presented. Although the proposed approach focuses on a single controlling factor, it shows important implications with water resources management and fluvial

  17. A Benthic Macroinvertebrate Multimetric Index for Assessment of the Ecological Integrity of Northeast Streams, Thailand

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    Nantiya Rattanachan


    Full Text Available This study aims to develop a benthic macroinvertebrate multimetric index for assessing the ecological quality of streams in Northeastern Thailand. ANOSIM indicated that the benthic macroinvertebrate assemblage in both of each basin and each season were not significantly different (R = 0.09, p = 0.24 and R = 0.07, p = 0.35, respectively. The efficacy metrics of each basin consisting of the Mekong II, the Chi, and the Mun basins were integrated and calibrated. A total of 255 data sets of water physico-chemical and benthic macroinvertebrates during the dry period (cool and hot seasons were obtained. The stream classification could be divided into three groups: the reference group (48 stations, the stressed group (42 stations, and the intermediate group (165 stations. Twelve out of 56 metrics have been considered as a core metric for the development of a biological index for quality streams in the Northeast, including Total taxa, EPT taxa, Ephemeroptera taxa, Coleoptera taxa, % EPT, % Chironomidae, % Tolerant individuals, % Intolerant individuals, Beck's index, HBI, Predator taxa, and Clinger taxa. Moreover, this metric set covered the structure and function of organisms including the diversity of species, community structure, tolerance/intolerance measures, functional feeding group, and habit. From the efficacy validation of the biological index, the results of stream assessment corresponded to the classification sites with the physico-chemical characteristics.

  18. Land Use Influences Niche Size and the Assimilation of Resources by Benthic Macroinvertebrates in Tropical Headwater Streams.

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    Diego Marcel Parreira de Castro

    Full Text Available It is well recognized that assemblage structure of stream macroinvertebrates changes with alterations in catchment or local land use. Our objective was to understand how the trophic ecology of benthic macroinvertebrate assemblages responds to land use changes in tropical streams. We used the isotope methodology to assess how energy flow and trophic relations among macroinvertebrates were affected in environments affected by different land uses (natural cover, pasture, sugar cane plantation. Macroinvertebrates were sampled and categorized into functional feeding groups, and available trophic resources were sampled and evaluated for the isotopic composition of 13C and 15N along streams located in the Cerrado (neotropical savanna. Streams altered by pasture or sugar cane had wider and more overlapped trophic niches, which corresponded to more generalist feeding habits. In contrast, trophic groups in streams with native vegetation had narrower trophic niches with smaller overlaps, suggesting greater specialization. Pasture sites had greater ranges of resources exploited, indicating higher trophic diversity than sites with natural cover and sugar cane plantation. We conclude that agricultural land uses appears to alter the food base and shift macroinvertebrate assemblages towards more generalist feeding behaviors and greater overlap of the trophic niches.

  19. Effects of hydrologic connectivity on aquatic macroinvertebrate assemblages in different marsh types (United States)

    Kang, Sung-Ryong; King, Sammy L.


    Hydrologic connectivity can be an important driver of aquatic macroinvertebrate assemblages. Its effects on aquatic macroinvertebrate assemblages in coastal marshes, however, are relatively poorly studied. We evaluated the effects of lateral hydrologic connectivity (permanently connected ponds: PCPs; temporary connected ponds: TCPs), and other environmental variables on aquatic macroinvertebrate assemblages and functional feeding groups (FFGs) in freshwater, brackish, and saline marshes in Louisiana, USA. We hypothesized that (1) aquatic macroinvertebrate assemblages in PCPs would have higher assemblage metric values (density, biomass, Shannon-Wiener diversity) than TCPs and (2) the density and proportional abundance of certain FFGs (i.e. scrapers, shredders, and collectors) would be greater in freshwater marsh than brackish and saline marshes. The data in our study only partially supported our first hypothesis: while freshwater marsh PCPs had higher density and biomass than TCPs, assemblage metric values in saline TCPs were greater than saline PCPs. In freshwater TCPs, long duration of isolation limited access of macroinvertebrates from adjacent water bodies, which may have reduced assemblage metric values. However, the relatively short duration of isolation in saline TCPs provided more stable or similar habitat conditions, facilitating higher assemblage metric values. As predicted by our second hypothesis, freshwater PCPs and TCPs supported a greater density of scrapers, shredders, and collectors than brackish and saline ponds. Aquatic macroinvertebrate assemblages seem to be structured by individual taxa responses to salinity as well as pond habitat attributes.

  20. Effects of engineered application of Eichhornia crassipes on the benthic macroinvertebrate diversity in Lake Dianchi, an ultra-eutrophic lake in China. (United States)

    Zhang, Zhiyong; Wang, Zhi; Zhang, Zhenghua; Zhang, Junqian; Guo, Junyao; Li, Enhua; Wang, Xuelei; Liu, Haiqin; Yan, Shaohua


    An ecological engineering project with confined growth of 1.5 km(2) of Eichhornia crassipes was implemented to remove pollutants in Lake Dianchi. To assess the ecological effects of this project on benthic macroinvertebrate assemblages, a 1-year investigation at the areas inside and outside E. crassipes mats was conducted from May 2013 to May 2014. All the 10 sampling sites in the areas were grouped into two statistically significant clusters mainly corresponding to inside and outside E. crassipes mat areas (EMAs), by clustering analysis. E. crassipes reduced the densities of pollution indicator taxa (e.g., Oligochaeta and Chironomidae larvae); thus, the total densities of benthic macroinvertebrates at the area inside EMAs (mean 328.2 ind./m(2)) were slightly lower than that at the area outside EMAs (mean 505.6 ind./m(2)). Four functional feeding groups including 38 species of benthic macroinvertebrates were collected at the area inside EMAs, while only three functional feeding groups containing 17 species were collected at the area outside EMAs. The biodiversity indices (Shannon-Weiner, Margalef, Simpson, and Peilou indices) and K-dominance curves also showed higher diversity of benthic macroinvertebrates at the area inside EMAs than at the area outside EMAs. These results suggested that a certain scale of engineering application of E. crassipes was beneficial to benthic macroinvertebrate communities in the ultra-eutrophic Lake Dianchi and it could be used as a pioneer species in ultra-eutrophic lake for pollutant removal.

  1. Patrones de distribución espacial de ensambles de macroinvertebrados bentónicos de un sistema fluvial Andino Patagónico Spatial distribution patterns of benthic macroinvertebrates assemblages in an Andean Patagonian fluvial system

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    Full Text Available En enero de 2006 se estudiaron los patrones espaciales de distribución de comunidades de macroinvertebrados bentónicos de la cuenca hidrográfica del río Baker (45°50' O y 47°55' S y los principales factores controladores, intentando cubrir la mayor variedad de ecosistemas lóticos. Para llevar a cabo el estudio se seleccionaron 27 estaciones de muestreo ubicadas en las diferentes subcuencas del río. En cada estación se realizó una caracterización fisicoquímica del agua (conductividad, oxígeno disuelto, pH, temperatura y turbidez, y se documentaron las características del tramo de río (e.g. ancho del cauce y tipo de sedimento e información cartográfica utilizando un sistema de información geográfica (SIG. Se identificaron un total de 51 taxa que correspondieron en su mayoría a larvas de insectos (80 %. Los grupos con mayor riqueza fueron los órdenes Ephemeroptera (15 taxa, Plecoptera (8 taxa y Trichoptera (8 taxa. Los análisis de clasificación y ordenación realizados con los datos de abundancia, permitieron reconocer siete grupos de estaciones diferentes (A-F que fueron estadísticamente significativos (P In January of 2006 we studied the distributional patterns of benthic macroinvertebrate communities of the Baker river basin (45°50' O and 47°55' S and their main controlling factors trying to cover the greater variety of the lotic ecosystems. To carry out the study, 27 sampling stations were located in the different sub basins of the river. In each station, physical-chemical parameters of the column of water were quantified (conductivity, dissolved oxygen, pH, temperature and turbidity, and documented characteristics of the segment (e.g. wide of the channel and sediment type and cartographic information using a geographic information system (GIS and complemented with cartographic information using GIS. Identified a total of 51 taxa, are mostly insect larvae (80 %. The groups most richness were orders Ephemeroptera (15


    Using redundancy analysis (RDA) and canonical correspondence analysis (CCA), we assessed relationships among chemical and physical characteristics and macroinvertebrate assemblages at stream sites sampled by the Regional Environmental Monitoring and Assessment Program (R-EMAP) in...

  3. Amphibian and benthic macroinvertebrate response to physical and chemical properties of Themi River, Arusha, Tanzania


    Lyimo, Emmanuel


    I hypothesized that variation in physical and chemical properties and habitat destruction of the Themi River as a result of human activities would affect abundance and diversity of amphibian and benthic macroinvertebrates. Variation in habitat physical and chemical conditions, and amphibian and benthic macroinvertebrate diversity and abundance were assessed in the Themi River of Arusha municipality. These physical, chemical and biological conditions were assessed at forty sampling stations...

  4. Development of rapid bioassessment approaches using benthic macroinvertebrates for Thai streams. (United States)

    Boonsoong, Boonsatien; Sangpradub, Narumon; Barbour, Michael T


    Thailand currently lacks formal bioassessment approaches and protocols to assist management decisions for water quality. The aim of this research is to develop a practical method of rapid bioassessment for a professional level by using benthic macroinvertebrate assemblages for streams in Thailand. Eleven reference and nine test sites were sampled in the headwater streams of the Loei River and adjacent areas to explore the development of a practical protocol. Specific physico-chemical parameters were selected to provide ecological information supplemental to the biological indicators. The biological research was designed around the USEPA Rapid Bioassessment Protocols (RBPs) using the multi-habitat approach. Four fixed-count subsamplings (100, 200, 300 and 500 organisms) were randomly conducted using a standardized gridded pan to evaluate an appropriate level for bioassessment in Thai streams. A 300 organism subsample is adequate for bioassessment purposes in Thai stream (evaluated by calculating dissimilarity values and ordination techniques). A systematic selection of candidate reference sites, metric selection, and index calibration was part of this research. Multimetric and multivariate analyses were examined as a foundation for bioassessment in Thailand. The multimetric approach appears to be more practical for a rapid bioassessment technique. Nine core metrics were identified for biological index score including number of total taxa, Diptera taxa, Ephemeroptera, Plecoptera, Trichoptera, and Coleoptera taxa, (%) Plecoptera, (%) Tolerant organisms, Beck's Biotic Index, (%) Intolerant organisms, Shredders taxa and Clingers taxa were calibrated for the final index. As a result of multimetric and multivariate analyses, family level identification data effectively discriminated reference condition and broad-scale environmental gradients. Hampered by incomplete taxonomic knowledge of benthic macroinvertebrates in Thailand, family-level identification may be sufficient

  5. Relationships of field habitat measurements, visual habitat indices, and land cover to benthic macroinvertebrates in urbanized streams of the Santa Clara Valley, California (United States)

    Fend, S.V.; Carter, J.L.; Kearns, F.R.


    We evaluated several approaches for measuring natural and anthropogenic habitat characteristics to predict benthic macroinvertebrate assemblages over a range of urban intensity at 85 stream sites in the Santa Clara Valley, California. Land cover was summarized as percentage urban land cover and impervious area within upstream buffers and the upstream subwatersheds. Field measurements characterized water chemistry, channel slope, sediment, and riparian canopy. In . addition to applying the visual-based habitat assessment in U.S. Environmental Protection Agency's rapid bioassessment protocol, we developed a simplified urban habitat assessment index based on turbidity, fine sediment deposition, riparian condition, and channel modification. Natural and anthropogenic habitat variables covaried along longitudinal stream gradients and were highly correlated with elevation. At the scale of the entire watershed, benthic macroinvertebrate measures were equally correlated with variables expressing natural gradients and urbanization effects. When natural gradients were reduced by partitioning sites into ecoregion subsection groupings, habitat variables most highly correlated with macroinvertebrate measures differed between upland and valley floor site groups. Among the valley floor sites, channel slope and physical modification of channel and riparian habitats appeared more important than upstream land cover or water quality in determining macroinvertebrate richness and ordination scores. Among upland sites, effects of upstream reservoir releases on habitat quality appeared important. Rapid habitat evaluation methods appeared to be an effective method for describing habitat features important to benthic macroinvertebrates when adapted for the region and the disturbance of interest. ?? 2005 by the American Fisheries Society.

  6. Colonization by benthic macroinvertebrates in two artificial substrate types of a Riparian Forest

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    Lívia Borges dos Santos

    Full Text Available Abstract: Aim To analyze the efficiency of organic and inorganic substrates in samples of benthic macroinvertebrates of riparian forests from the Cerrado. Specific objectives (i characterize the ecological succession and taxonomic richness of benthic macroinvertebrates in stream affluent of a riparian forest; (ii analyze the influence of seasonality on the colonization of macroinvertebrates; and (iii determine the effect of the types of artificial substrates on the richness, composition and abundance of the benthic community. Methods Sampling was carried out in the rainy and dry seasons, and we installed in the watercourse two types of substrates: organic (leaf packs and inorganic (bricks, organized in pairs. Six samples per season were done to verify colonization, succession, richness and abundance of benthic community. The substrates were carefully sorted and the organisms were identified to the lowest possible taxonomic level. Results The ecological succession was clearly observed, with the initial occurrence of Chironomidae and Baetidae (considered early colonizers, and a late occurrence of organisms such as Helotrephidae and Trichoptera (considered late colonizers. No significant difference was found in the richness and abundance among the studied seasons (rainy and dry, but the organic substrate was significantly higher than the inorganic substrate for these parameters. Conclusion Organic artificial substrates are more efficient in characterizing the community of benthic macroinvertebrates in the study area, because they are more similar to the conditions of the substrate found naturally in the environment.

  7. Patterning exergy of benthic macroinvertebrate communities using self-organizing maps

    NARCIS (Netherlands)

    Park, Y.S.; Lek, S.; Scardi, M.; Verdonschot, P.F.M.; Jørgensen, S.E.


    Exergy is a measure of the free energy of a system with contributions from all components including the energy of organisms, and it is used as an ecological indicator. In this study, we implemented a self-organizing map (SOM) for patterning exergy of benthic macroinvertebrate communities. The datase

  8. Spatial variation in lake benthic macroinvertebrate ecological assessment: a synthesis of European case studies

    DEFF Research Database (Denmark)

    Sandin, Leif Leonard; Solimini, Angelo G.


    This paper summarizes eight case studies that were analysed as part of the research theme ``lake benthic macroinvertebrates'' forming part of the EU-funded WISER project ``Water bodies in Europe: Integrative Systems to assess Ecological status and Recovery''. The relationships between lake benthi...

  9. Benthic macroinvertebrate based indices for assessing the ecological status of freshwaters on oceanic islands

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    Full Text Available Following the Water Framework Directive (2000/60/EC, macroinvertebrates are required biological elements for monitoring European aquatic ecosystems. Several efforts have been made towards establishing a biomonitoring programme for the Azores freshwater systems using benthic macroinvertebrates. However, little was previously known concerning Azorean freshwater macroinvertebrate fauna. Data from a major ongoing survey of macroinvertebrate freshwater fauna for two islands are presented and the use ofmacroinvertebrates as water quality indicators for the Azorean streams is evaluated. The upper, middle and lower reaches of streams longer than 10 km from São Miguel (10 and Santa Maria (1 were surveyed (a total of 33 samples. A total of 21 taxa were collected;Diptera, in particular chironomidae, were dominant; chironomids were collected from all sampling sites. The Azorean lotic fauna is characterized by low levels of abundance and the absence of macroinvertebrate groups commonly associated with continental systems.Traditional biotic indices, used to classify ecological quality, yielded poor to bad classifications despite little or no environmental impacts at the sampling sites. The paucityof macroinvertebrate fauna is probably due to the result of geological and physicochemical processes, the oceanic character of the islands, their volcanic origin, small size and geological youth and climate related factors such as seasonal peaks in rainfall. Considering these constraints, we demonstrate that watershed age plays a determinant role in shaping Azorean macroinvertebrate freshwater communities which can confound the water quality classification via the use of traditional biotic indices.

  10. Anthropogenic disturbance and landscape patterns affect diversity patterns of aquatic benthic macroinvertebrates (United States)

    Maloney, K.O.; Munguia, P.; Mitchell, R.M.


    Measures of species diversity are valuable tools for assessing ecosystem health. However, most assessments have addressed individual sites or regional taxon pools, with few comparisons of differences in assemblage composition within or among regions. We examined the effects of anthropogenic disturbance on local richness (?? diversity) and species turnover (?? diversity) of benthic macroinvertebrates in small streams within and between 2 ecoregions (Northern Piedmont vs Southeastern Plains ecoregions) of the Patuxent River basin (Maryland, USA). Regional species pools did not differ between ecoregions (Piedmont = 166 taxa, Plains = 162 taxa); however, local richness was lower in the Plains (mean = 17.4 taxa/stream) compared to the Piedmont (mean = 22.2 taxa/stream). When streams were categorized into disturbance classes (low, medium, high), local richness did not differ among categories for either region. However, at the entire Patuxent scale, local richness tended to decrease with % impervious cover in a watershed. Variation in species composition, analyzed with nonmetric multidimensional scaling (nMDS), differed significantly between Piedmont and Plains streams, and Plains streams had higher ?? diversity than Piedmont streams. When partitioned by disturbance category and region, ?? diversity differed only between the low-disturbance sites (Plains > Piedmont). Relationships between ?? diversity and environmental variables varied by region. ?? diversity was weakly negatively related to % row-crop cover in a watershed at the entire Patuxent scale. For the Piedmont region, ?? diversity tended to decrease with % forest, % pasture, and % row-crop cover in a watershed. Such negative relationships between ?? diversity and landuse variables indicate a possible homogenization of the assemblage. The incongruence between diversity measures and composition measures, together with differing effects of anthropogenic land use on ?? diversity in the 2 regions, emphasizes the need

  11. Anthropogenic impact on water chemistry and benthic macroinvertebrate associated changes in a southern Nigeria stream. (United States)

    Arimoro, Francis O; Odume, O Nelson; Uhunoma, Samson I; Edegbene, Augustine O


    The Ogba River in southern Nigeria is an important water resource for its riparian communities. This study evaluates impact of anthropogenic influences on the Ogba River using water chemistry and macroinvertebrate data sets obtained over a period of 6 months between January and June 2012. Four stations, stations 1-4, characterised by various human activities were chosen along the river. Organic wastes from domestic and industrial sources were the major point sources of pollutants. Station 2 where the municipal wastewater drains into the river had elevated values of flow velocity, BOD5, sulphate, phosphate, nitrate and sodium. Based on the canonical correspondence analysis (CCA), 5-day biochemical oxygen demand (BOD5), sulphate, nitrate and phosphate were the main factors that help to shape the macroinvertebrate assemblage structure of the Ogba River. Macroinvertebrates clustered strongly by stations than by seasons indicating that water quality differences between the stations were responsible for the observed differences in the biotic assemblage. The preponderance of naidid oligochaetes, baetid nymphs and certain tolerant dipteran taxa including chironomids and ceratopogonids at all four stations was an indication that the entire water body was stressed. The odonates were the single most abundant taxa; their dominance could be attributed to the vegetative nature of the stream, favouring odonate colonisation. Overall, the responses of macroinvertebrates to stress were reflected by the different assemblage structures recorded at the four study stations. Substrate and microhabitat obliteration and poor water quality appeared to be the factors responsible for the observed assemblage structure in the Ogba River.

  12. Biodiversity of benthic macroinvertebrates in Air Terjun Asahan, Asahan, Melaka, Malaysia (United States)

    Nurhafizah-Azwa, S.; Ahmad A., K.


    A study on benthic macroinvertebrate diversity was conducted at Air Terjun Asahan, Asahan, Melaka. Five stations were selected with distance intervals of approximately 500 metres. Three replicates of benthic macroinvertebrate and water samples were taken. Results classified Air Terjun Asahan in class II, which indicated good water quality based on WQI recommended by the Department of Environment. A total of 1 phylum, 2 classes, 6 order, 30 families, and 2183 individuals were successfully sampled and recorded. The analysis showed that the average value of Shannon Diversity Index, H' (2.19), Pielou Evenness Index, J' (0.30), and Margaleff Richness Index, DMG (3.77) described that Air Terjun Asahan was in moderate condition and the distribution of macroinvertebrates was uniform between stations. Correlation test showed that the WQI had a strong relationship with the diversity indices involved. BMWP, and FBI showed that Air Terjun Asahan was in good water quality. CCA test was conducted to show environmental factors towards benthic macroinvertebrate distribution. The presence of Leptophlebiidae, Baetidae, Heptageniidae and Chironomidae with high abundance of the families showed the potential as biological indicators of a clean ecosystem.

  13. Trace element contamination in benthic macroinvertebrates from a small stream near a uranium mill tailings site. (United States)

    Peterson, M J; Smith, J G; Southworth, G R; Ryon, M G; Eddlemon, G K


    Direct measurement of the accumulation of non-radioactive trace elements in aquatic biota near uranium mining or processing sites has been relatively rare, with greater focus on the radiological activity in the adjacent soils and groundwater. To evaluate the potential ecological concern associated with trace elements at a former uranium mill site in southeastern Utah, benthic macroinvertebrates were collected and analyzed for 17 trace elements from multiple locations within a small on-site stream, Montezuma Creek, and a nearby reference stream. Key questions of this study relate to the spatial and temporal extent of contamination in aquatic biota, the potential ecological risks associated with that contamination, and the usefulness of benthic macroinvertebrates as a monitoring tool at this site. Composite samples of similar macroinvertebrate taxa and functional feeding groups were collected from each site over a two year period that was representative of normal and dry-year conditions. In both years, mean concentrations of arsenic, molybdenum, selenium, and vanadium were significantly higher (a factor of 2-4 times: P mill tailing site in comparison to concentrations from reference locations. Mean uranium concentrations in invertebrates immediately downstream of the mill site were more than 10 times higher than at reference sites. The site-to-site pattern of contamination in Montezuma Creek invertebrates was similar in 1995 and 1996, with mill-related trace elements showing a downstream decreasing trend. However, nine of seventeen contaminant concentrations were higher in the second year of the study, possibly due to a higher influx of deep groundwater during the drier second year of the study. A preliminary assessment of ecological risks, based on the benthic macroinvertebrate bioaccumulation data, suggests that aquatic and terrestrial population risks are low. Benthic macroinvertebrates appeared to be sensitive integrators of trace element inputs to the aquatic

  14. Effects of agricultural and urban impacts on macroinvertebrates assemblages in streams (Rio Grande do Sul, Brazil

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    Luiz Ubiratan Hepp


    Full Text Available This study evaluates the effects of agricultural and urban activities on the structure and composition of benthic communities of streams in the state of Rio Grande do Sul, Brazil. Benthic macroinvertebrates were collected in streams influenced by urbanization and agriculture and in streams with no anthropogenic disturbances (reference streams. Organism density was superior in urban streams when compared with streams in the other two areas. The taxonomic richness and Shannon diversity index were higher in reference streams. The benthic fauna composition was significantly different among land uses. The classification and ordination analyses corroborated the results of variance analyses demonstrating the formation of clusters corresponding to streams with similar land use. Seasonality was also found to influence the benthic community, though in a lesser degree than land use.

  15. Spatial-temporal variability in water quality and macro-invertebrate assemblages in the Upper Mara River basin, Kenya (United States)

    Kilonzo, Fidelis; Masese, Frank O.; Van Griensven, Ann; Bauwens, Willy; Obando, Joy; Lens, Piet N. L.

    Tropical rivers display profound temporal and spatial heterogeneity in terms of environmental conditions. This aspect needs to be considered when designing a monitoring program for water quality in rivers. Therefore, the physico-chemical composition and the nutrient loading of the Upper Mara River and its two main tributaries, the Amala and Nyangores were monitored. Initial daily, and later a weekly monitoring schedule for 4 months spanning through the wet and dry seasons was adopted. Benthic macro-invertebrates were also collected during the initial sampling to be used as indicators of water quality. The aim of the current study was to investigate the physico-chemical status and biological integrity of the Upper Mara River basin. This was achieved by examining trends in nutrient concentrations and analyzing the structure, diversity and abundance of benthic macro-invertebrates in relation to varying land use patterns. Sampling sites were selected based on catchment land use and the level of human disturbance, and using historical records of previous water quality studies. River water pH, dissolved oxygen, electrical conductivity (EC), temperature, and turbidity were determined in situ. All investigated parameters except iron and manganese had concentration values within allowable limits according to Kenyan and international standards for drinking water. The Amala tributary is more mineralized and also shows higher levels of pH and EC than water from the Nyangores tributary. The latter, however, has a higher variability in both the total phosphorus (TP) and total nitrogen (TN) concentrations. The variability in TP and TN concentrations increases downstream for both tributaries and is more pronounced for TN than for TP. Macro-invertebrate assemblages responded to the changes in land use and water quality in terms of community composition and diversity. The study recommends detailed continuous monitoring of the water quality at shorter time intervals and to identify

  16. Benthic foraminiferal assemblages help to understand carbonate mound evolution (United States)

    Rüggeberg, A.; Dorschel, B.; Dullo, C.; Hebbeln, D.; Freiwald, A.


    On- and off-mound sediment cores from Propeller Mound (Porcupine Seabight) were analysed for their benthic foraminiferal assemblages. Benthic foraminifera from the off-mound position show three different assemblages describing the Holocene, Oxygen Isotope Stage (OIS) 2 and late OIS 3. The Holocene assemblage is dominated by Uvigerina mediterranea, Trifarina angulosa, Melonis barleeanum, Hyalinea balthica, Bulimina marginata. These species are related to a higher supply of organic material. The glacial assemblage shows high abundances of Cassidulina teretis, C. reniforme, Globocassidulina subglobosa, and Cibicidoides kullenbergi, implying cold bottom waters and a reduced productivity. The lower part of late OIS 3 is dominated by Elphidium excavatum, which is displaced continuously by very high abundances of C. teretis towards the transition of OIS3/2. E. excavatum, a shallow shelf species generally reported from above 200 m water depth, and high amounts of sediment supplied to the core site points to shelf erosion related to sea level lowering (approx. 50 m). Towards OIS 2 the system returns to normal background sedimentation pattern. We transferred the established off-mound assemblages onto the on-mound core, in which the sediment sequence is incomplete characterised by numerous hiatuses. The Holocene assemblage describes almost the complete core with relative abundances of >20%, interrupted only by three sections with slightly higher amounts of the glacial assemblage, which are not comparable to abundances of >70% of the glacial assemblage found in the off-mound core. These results are in conjunction with stable oxygen isotope data indicating only interstadial values, assuming peak glacial and interglacial sediments to be removed from the mound. Another assemblage described for the on-mound core is dominated by Discanomalina coronata, Gavelinopsis translucens, Planulina ariminensis, Cibicides lobatulus and to a lower degree by Hyrrokkin sarcophaga. These species

  17. The role of physical habitat and sampling effort on estimates of benthic macroinvertebrate taxonomic richness at basin and site scales. (United States)

    Silva, Déborah R O; Ligeiro, Raphael; Hughes, Robert M; Callisto, Marcos


    Taxonomic richness is one of the most important measures of biological diversity in ecological studies, including those with stream macroinvertebrates. However, it is impractical to measure the true richness of any site directly by sampling. Our objective was to evaluate the effect of sampling effort on estimates of macroinvertebrate family and Ephemeroptera, Plecoptera, and Trichoptera (EPT) genera richness at two scales: basin and stream site. In addition, we tried to determine which environmental factors at the site scale most influenced the amount of sampling effort needed. We sampled 39 sites in the Cerrado biome (neotropical savanna). In each site, we obtained 11 equidistant samples of the benthic assemblage and multiple physical habitat measurements. The observed basin-scale richness achieved a consistent estimation from Chao 1, Jack 1, and Jack 2 richness estimators. However, at the site scale, there was a constant increase in the observed number of taxa with increased number of samples. Models that best explained the slope of site-scale sampling curves (representing the necessity of greater sampling effort) included metrics that describe habitat heterogeneity, habitat structure, anthropogenic disturbance, and water quality, for both macroinvertebrate family and EPT genera richness. Our results demonstrate the importance of considering basin- and site-scale sampling effort in ecological surveys and that taxa accumulation curves and richness estimators are good tools for assessing sampling efficiency. The physical habitat explained a significant amount of the sampling effort needed. Therefore, future studies should explore the possible implications of physical habitat characteristics when developing sampling objectives, study designs, and calculating the needed sampling effort.

  18. L-Lake macroinvertebrate community

    Energy Technology Data Exchange (ETDEWEB)

    Specht, W.L.


    To characterize the present benthic macroinvertebrate community of L-Lake, Regions 5 and 7 of the reservoir were sampled in September 1995 at the same locations sampled in 1988 and 1989 during the L-Lake monitoring program. The macroinvertebrate community of 1995 is compared to that of 1988 and 1989. The species composition of L-Lake`s macroinvertebrate community has changed considerably since 1988-1989, due primarily to maturation of the reservoir ecosystem. L-Lake contains a reasonably diverse macroinvertebrate community that is capable of supporting higher trophic levels, including a diverse assemblage of fish species. The L-Lake macroinvertebrate community is similar to those of many other southeastern reservoirs, and there is no indication that the macroinvertebrate community is perturbed by chemical or physical stressors.

  19. Building functional groups of marine benthic macroinvertebrates on the basis of general community assembly mechanisms (United States)

    Alexandridis, Nikolaos; Bacher, Cédric; Desroy, Nicolas; Jean, Fred


    The accurate reproduction of the spatial and temporal dynamics of marine benthic biodiversity requires the development of mechanistic models, based on the processes that shape macroinvertebrate communities. The modelled entities should, accordingly, be able to adequately represent the many functional roles that are performed by benthic organisms. With this goal in mind, we applied the emergent group hypothesis (EGH), which assumes functional equivalence within and functional divergence between groups of species. The first step of the grouping involved the selection of 14 biological traits that describe the role of benthic macroinvertebrates in 7 important community assembly mechanisms. A matrix of trait values for the 240 species that occurred in the Rance estuary (Brittany, France) in 1995 formed the basis for a hierarchical classification that generated 20 functional groups, each with its own trait values. The functional groups were first evaluated based on their ability to represent observed patterns of biodiversity. The two main assumptions of the EGH were then tested, by assessing the preservation of niche attributes among the groups and the neutrality of functional differences within them. The generally positive results give us confidence in the ability of the grouping to recreate functional diversity in the Rance estuary. A first look at the emergent groups provides insights into the potential role of community assembly mechanisms in shaping biodiversity patterns. Our next steps include the derivation of general rules of interaction and their incorporation, along with the functional groups, into mechanistic models of benthic biodiversity.

  20. Effects of heavy metals on benthic macroinvertebrate communities in New Zealand streams

    Energy Technology Data Exchange (ETDEWEB)

    Hickey, C.W. [National Inst. of Water and Atmospheric Research, Hamilton (New Zealand); Clements, W.H. [Colorado State Univ., Fort Collins, CO (United States). Dept. of Fishery and Wildlife Biology


    The authors performed chemical analyses of heavy metals in water and periphyton, toxicity tests with Daphnia magna and an indigenous mayfly (Deleatidium sp.), and field surveys of benthic macroinvertebrates to estimate the degree of metal pollution in three catchments in the Coromandel Peninsula of New Zealand. Good agreement was found between toxicity tests and measures of benthic community structure, particularly at stations with the highest metal levels. Responses of benthic communities at stations with low or moderate levels of metal contamination were variable and were probably confounded by factors other than heavy metals. Effects of heavy metals on benthic communities in New Zealand streams were similar to those reported for metal-polluted streams in North America and Europe, suggesting that responses to metal contamination are predictable. Abundance and species richness of mayflies, number of taxa in the orders Ephemeroptera, Plecoptera, and Trichoptera, and total taxonomic richness were the best indicators of heavy metals in New Zealand streams. In contrast, the quantitative macroinvertebrate community index (QMCI), a biotic index proposed for assessing effects of organic enrichment in New Zealand streams, could not distinguish between reference and metal-polluted streams. The poor performance of the QMCI was primarily due to incorrect tolerance scores for some taxa to heavy metals. Because of concerns regarding the subjective assignment of tolerance values to species, the authors recommend that tolerance values for dominant species in New Zealand streams should be verified experimentally in stream microcosms.

  1. The impact of sediment removal on the aquatic macroinvertebrate assemblage in a fishpond littoral zone

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    Zdeněk ADÁMEK


    Full Text Available Bottom sediment removal, a widely used technique in restoration management of standing water bodies, has a strong influence on communities of aquatic organisms. As most information on the impact of sediment removal on the aquatic environment comes from studies on lakes, the aim of this study was to describe macroinvertebrate assemblage succession in a fishpond (Štěpánek fishpond, Bohemian-Moravian highlands, Czech Republic littoral zone following restoration by sediment removal during the winter of 2003/2004. Semi-quantitative hand net sampling was undertaken one year before (2003 and in each of the following five years (2004–2008 after sediment removal. A significant decrease in both abundance (approx. 90% of individuals and diversity (approx. 30% of taxa of macroinvertebrates was detected immediately after pond restoration. The values gradually increased over subsequent years, reaching comparable abundance and diversity three years after sediment removal. A significant shift was recorded in the taxonomic and functional composition of the macroinvertebrate assemblage after sediment removal. Mayfly larvae were the dominant invertebrates before restoration, while chironomid larvae and oligochaetes dominated after sediment removal. Phytophilous taxa, grazers and scrapers, and swimming or diving invertebrates were common in 2003, whilst open-water taxa preferring mud and other mostly inorganic microhabitats, gatherers/collectors, and burrowing/boring invertebrates were relatively common after sediment removal. In 2008, the assemblage reverted towards the situation before sediment removal, probably connected with a lower water level and accelerated macrophyte bed succession. Principal Component Analysis on the species data confirmed the differences in invertebrate taxonomic structure among sampling years. Succession of the fishpond invertebrate assemblage in the years following sediment removal was mainly influenced by fish farming practice and

  2. Trends in Benthic macroinvertebrate community Biomass and Energy Budgets in Lake Sevan, 1928-2004 (United States)

    Stapanian, Martin A.; Jenderedjian, K.; Hakobyan, S.


    Water levels of Lake Sevan (Armenia) were artificially lowered by nearly 20 m between 1949 and 1997. Lowered water levels, combined with increased eutrophication, were associated with seasonally anoxic conditions (lasting 1–4 months) near the bottom of the profundal zone each year during 1976–2004. In addition, the extents of the macrophyte zone and of certain substrate types were severely reduced following drawdown. Maximal depth of occurrence decreased by 2–44 m for at least for 50 species of benthic macroinvertebrates between 1982 and 2004 compared to 1937–1961. Species richness of benthic macroinvertebrates declined from 25 to three species at depths where seasonal anoxia occurred. Total biomass increased by a factor of 10 from the period 1928–1948 to 1976–1979 then declined by a factor of 3 to 4 between 1987 and 2004. Energy flow through detritivores was more than tripled during 1976–2004 compared to 1928–1971, a result of increased plankton primary production. In contrast, energy flow through herbivorous benthic macroinvertebrates decreased by a factor of nearly 5, due to reduced areal coverage of macrophytes. Energy flow through filter feeders did not change over the time period examined, but energy flow through the entire zoobenthos community was nearly tripled. The biomasses of Oligochaeta, Chironomidae, and total zoobenthos showed a delayed response to changes in primary production of 7–9, 2, and 2–4 years, respectively. These patterns may provide a basis to predict results of restoration efforts based on the abundance of the zoobenthos in future years as the level of the lake is restored and water quality improves.

  3. Response of benthic macroinvertebrate communities to highway construction in an Appalachian watershed (United States)

    Hedrick, Lara B.; Welsh, S.A.; Anderson, James T.; Lin, L.-S.; Chen, Y.; Wei, X.


    Highway construction in mountainous areas can result in sedimentation of streams, negatively impacting stream habitat, water quality, and biotic communities. We assessed the impacts of construction of a segment of Corridor H, a four-lane highway, in the Lost River watershed, West Virginia, by monitoring benthic macroinvertebrate communities and water quality, before, during, and after highway construction and prior to highway use at upstream and downstream sites from 1997 through 2007. Data analysis of temporal impacts of highway construction followed a Before-After-Control-Impact (BACI) study design. Highway construction impacts included an increase in stream sedimentation during the construction phase. This was indicated by an increase in turbidity and total suspended solids. Benthic macroinvertebrate metrics indicated a community more tolerant during and after construction than in the period before construction. The percent of Chironomidae and the Hilsenhoff Biotic Index (HBI) increased, while percent of Ephemeroptera, Plecoptera, and Trichoptera (EPT) decreased. Our 10-year study addressed short-term impacts of highway construction and found that impacts were relatively minimal. A recovery of the number of EPT taxa collected after construction indicated that the benthic macroinvertebrate community may be recovering from impacts of highway construction. However, this study only addressed a period of 3 years before, 3 years during, and 4 years post construction. Inferences cannot be made concerning the long-term impacts of the highway, highway traffic, runoff, and other factors associated with highway use. Continual monitoring of the watershed is necessary to determine if the highway has a continual impact on stream habitat, water quality, and biotic integrity. ?? 2010 Springer Science+Business Media B.V.

  4. Diversity assessment of benthic macroinvertebrates, yeasts, and microbiological indicators along a longitudinal gradient in Serra do Cipó, Brazil

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    M. Callisto

    Full Text Available The main goals of this study were: 1 to evaluate the structure, diversity, and functional trophic group composition of benthic macroinvertebrate communities; 2 to characterize water quality in the headwaters of the Doce river watershed, based on physical, chemical, and biological parameters (benthic macroinvertebrates, fecal coliforms, heterotrophic bacteria, and yeasts; and 3 to contribute to the knowledge of the structure and function of longitudinal gradients in lotic ecosystems in Brazil. A total of 60 benthic macroinvertebrate taxa were identified, the dominant group being the aquatic insects, with 50 families distributed in 8 orders. The dry period presented higher values of taxonomic richness and total density of benthic macroinvertebrates. A decreasing gradient was observed in these variable values from the 3rd order stretch down to the 6th order stretch. The highest Shannon-Wiener diversity values were found in the rainy period in the 3rd order stretches, which presented well-developed riparian forest. Besides the 3rd order stretches, the Pielou evenness index values were also high in the 6th order stretch. The collectors, together with the scrapers, predominated in the benthic macroinvertebrate communities in all river stretches, except in the 2nd, 4th, and 5th order stretches in the rainy period, where communities were dominated by filterers. The shredders and predators presented low densities for all river stretches. All microbiological variables presented low levels. Due to the high counts of heterotrophic bacteria and coliforms, the studied river stretches presented inadequate potability but adequate balneability levels. The results suggest that the structure, diversity, and composition of the benthic macroinvertebrate communities are influenced by the trophic resource availability, seasonality, and sediment heterogeneity. The microbiological results of this study allow inferring that the waters from Serra do Cipó have excellent

  5. Relationships between ecosystem metabolism, benthic macroinvertebrate densities, and environmental variables in a sub-arctic Alaskan river (United States)

    Benson, Emily R.; Wipfli, Mark S.; Clapcott, Joanne E.; Hughes, Nicholas F.


    Relationships between environmental variables, ecosystem metabolism, and benthos are not well understood in sub-arctic ecosystems. The goal of this study was to investigate environmental drivers of river ecosystem metabolism and macroinvertebrate density in a sub-arctic river. We estimated primary production and respiration rates, sampled benthic macroinvertebrates, and monitored light intensity, discharge rate, and nutrient concentrations in the Chena River, interior Alaska, over two summers. We employed Random Forests models to identify predictor variables for metabolism rates and benthic macroinvertebrate density and biomass, and calculated Spearman correlations between in-stream nutrient levels and metabolism rates. Models indicated that discharge and length of time between high water events were the most important factors measured for predicting metabolism rates. Discharge was the most important variable for predicting benthic macroinvertebrate density and biomass. Primary production rate peaked at intermediate discharge, respiration rate was lowest at the greatest time since last high water event, and benthic macroinvertebrate density was lowest at high discharge rates. The ratio of dissolved inorganic nitrogen to soluble reactive phosphorus ranged from 27:1 to 172:1. We found that discharge plays a key role in regulating stream ecosystem metabolism, but that low phosphorous levels also likely limit primary production in this sub-arctic stream.

  6. Development of a local-scale urban stream assessment method using benthic macroinvertebrates: An example from the Santa Clara Basin, California (United States)

    Carter, J.L.; Purcell, A.H.; Fend, S.V.; Resh, V.H.


    Research that explores the biological response to urbanization on a site-specific scale is necessary for management of urban basins. Recent studies have proposed a method to characterize the biological response of benthic macroinvertebrates along an urban gradient for several climatic regions in the USA. Our study demonstrates how this general framework can be refined and applied on a smaller scale to an urbanized basin, the Santa Clara Basin (surrounding San Jose, California, USA). Eighty-four sampling sites on 14 streams in the Santa Clara Basin were used for assessing local stream conditions. First, an urban index composed of human population density, road density, and urban land cover was used to determine the extent of urbanization upstream from each sampling site. Second, a multimetric biological index was developed to characterize the response of macroinvertebrate assemblages along the urban gradient. The resulting biological index included metrics from 3 ecological categories: taxonomic composition ( Ephemeroptera, Plecoptera, and Trichoptera), functional feeding group (shredder richness), and habit ( clingers). The 90th-quantile regression line was used to define the best available biological conditions along the urban gradient, which we define as the predicted biological potential. This descriptor was then used to determine the relative condition of sites throughout the basin. Hierarchical partitioning of variance revealed that several site-specific variables (dissolved O2 and temperature) were significantly related to a site's deviation from its predicted biological potential. Spatial analysis of each site's deviation from its biological potential indicated geographic heterogeneity in the distribution of impaired sites. The presence and operation of local dams optimize water use, but modify natural flow regimes, which in turn influence stream habitat, dissolved O2, and temperature. Current dissolved O2 and temperature regimes deviate from natural

  7. Abyssal hills: Influence of topography on benthic foraminiferal assemblages (United States)

    Stefanoudis, Paris V.; Bett, Brian J.; Gooday, Andrew J.


    Abyssal plains, often thought of as vast flat areas, encompass a variety of terrains including abyssal hills, features that constitute the single largest landscape type on Earth. The potential influence on deep-sea benthic faunas of mesoscale habitat complexity arising from the presence of abyssal hills is still poorly understood. To address this issue we focus on benthic foraminifera (testate protists) in the >150-μm fraction of Megacorer samples (0-1 cm layer) collected at five different sites in the area of the Porcupine Abyssal Plain Sustained Observatory (NE Atlantic, 4850 m water depth). Three sites are located on the tops of small abyssal hills (200-500 m elevation) and two on the adjacent abyssal plain. We examined benthic foraminiferal assemblage characteristics (standing stock, diversity, composition) in relation to seafloor topography (hills vs. plain). Density and rarefied diversity were not significantly different between the hills and the plain. Nevertheless, hills do support a higher species density (i.e. species per unit area), a distinct fauna, and act to increase the regional species pool. Topographically enhanced bottom-water flows that influence food availability and sediment type are suggested as the most likely mechanisms responsible for these differences. Our findings highlight the potential importance of mesoscale heterogeneity introduced by relatively modest topography in regulating abyssal foraminiferal diversity. Given the predominance of abyssal hill terrain in the global ocean, we suggest the need to include faunal data from abyssal hills in assessments of abyssal ecology.

  8. Benthic macroinvertebrates as bioindicators of water quality in an Atlantic forest fragment

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    Augusto Oliveira


    Full Text Available The objective of this study was to evaluate benthic macroinvertebrate communities as bioindicators of water quality in five streams located in the "Reserva Particular do Patrimônio Natural" (RPPN Mata Samuel de Paula and its surroundings, in the municipality of Nova Lima near the city of Belo Horizonte, Minas Gerais State, southeastern Brazil. This region has been strongly modified by human activities including mining and urbanization. Samples were collected in the field every three months between August 2004 and November 2005, totaling six samplings in the rainy and dry seasons. This assessment identified one area ecologically altered while the other sampling sites were found to be minimally disturbed systems, with well-preserved ecological conditions. However, according to the Biological Monitoring Work Party (BMWP and the Average Score Per Taxon (ASPT indices, all sampling sites had excellent water quality. A total of 14,952 organisms was collected, belonging to 155 taxa (148 Insecta, two Annelida, one Bivalvia, one Decapoda, one Planariidae, one Hydracarina, and one Entognatha. The most abundant benthic groups were Chironomidae (47.9%, Simuliidae (12.3%, Bivalvia (7.5%, Decapoda (6.1%, Oligochaeta (5.2%, Polycentropodidae (3.7%, Hydropsychidae (2.5%, Calamoceratidae (1.8%, Ceratopogonidae (1.7%, and Libellulidae (1.2%. The assessment of the benthic functional feeding groups showed that 34% of the macroinvertebrates were collector-gatherers, 29% predators, 24% collector-filterers, 8% shredders, and 5% scrapers. The RPPN Mata Samuel de Paula comprises diversified freshwater habitats that are of great importance for the conservation of many benthic taxa that are intolerant to organic pollution.

  9. Permafrost thaw and intense thermokarst activity decreases abundance of stream benthic macroinvertebrates. (United States)

    Chin, Krista S; Lento, Jennifer; Culp, Joseph M; Lacelle, Denis; Kokelj, Steven V


    Intensification of permafrost thaw has increased the frequency and magnitude of large permafrost slope disturbances (mega slumps) in glaciated terrain of northwestern Canada. Individual thermokarst disturbances up to 40 ha in area have made large volumes of previously frozen sediments available for leaching and transport to adjacent streams, significantly increasing sediment and solute loads in these systems. To test the effects of this climate-sensitive disturbance regime on the ecology of Arctic streams, we explored the relationship between physical and chemical variables and benthic macroinvertebrate communities in disturbed and undisturbed stream reaches in the Peel Plateau, Northwest Territories, Canada. Highly disturbed and undisturbed stream reaches differed with respect to taxonomic composition and invertebrate abundance. Minimally disturbed reaches were not differentiated by these variables but rather were distributed along a disturbance gradient between highly disturbed and undisturbed sites. In particular, there was evidence of a strong negative relationship between macroinvertebrate abundance and total suspended solids, and a positive relationship between abundance and the distance from the disturbance. Increases in both sediments and nutrients appear to be the proximate cause of community differences in highly disturbed streams. Declines in macroinvertebrate abundance in response to slump activity have implications for the food webs of these systems, potentially leading to negative impacts on higher trophic levels, such as fish. Furthermore, the disturbance impacts on stream health can be expected to intensify as climate change increases the frequency and magnitude of thermokarst.

  10. Effects of ambient metals concentrations on the benthic macroinvertebrate community in the Animas River, Colorado

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    Covington, S.M.; Parkhurst, B.R. [Cadmus Group Inc., Laramie, WY (United States); Perino, L. [Sunnyside Gold Corp., Silverton, CO (United States)


    The Upper Animas River is located in southern Colorado at approximately 9500 feet above mean sea level near the town of Silverton in San Juan County. It drains several first and second order creeks and gulches, many of which are subject to water quality impacts from natural sources of metals and acid mine drainage and mine tailings from historical mining activity. When the State of Colorado proposed new designated uses with more stringent metal standards for the Upper Animas River, Sunnyside Gold Corp was concerned that these new proposed designated uses and their associated standards were unattainable primarily because of existing poor ambient water quality. Studies were designed to address this and other issues. This presentation focuses on ambient metal concentrations and their effect on macroinvertebrate density and composition. Aluminum, cadmium, copper, iron, manganese, and zinc were measured in the water column and in the precipitate on the gravel-cobble substrates at each location. Macroinvertebrate samples were also collected at these locations. The trends in benthic macroinvertebrate community composition in relationship to metal concentration and distribution will be discussed.

  11. Ecological assessment of the Tajan river using feeding groups of benthic macroinvertebrates and biotic indices

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    M Sharifinia


    Full Text Available One of the best practical methods to understand ecological status of a water body and determine impacts of human intervention in reducing water quality is using benthic macroinvertebrates as assessment tools for monitoring their biological integrity and health. The Tajan River is one of the rivers of Caspian Southernsub-basin that drains the Caspian Sea. Macroinvertebrate samples were taken using Surber’s sampler (40 x 40 cm and 100µ mesh size in 45 day intervals with 3 replicates in each sampling site for a period of one year (May 2010 to May 2011. The collected organisms were preserved in 4% formalin solution and transferred to the laboratory for identification and counting. Six different functional feeding groups of macroinvertebrate e.g. Collector-gathering, Collector-filtering, Predator, Collector-gathering /Scraper, Predator/Collector-gathering and Scraper were determined. Feeding groups of Collector-gathering, Collector-filtering and Collector-gathering /Scraper were relatively dominant in comparison to other groups. Groups of Collector-filtering and Collector-gathering were dominant in slightly and heavily polluted stations, respectively. In this study population structure measures including abundance, EPT percent and the EPT and EPT/CHIR indics were mearsured. Species diversity, species richness were also determined using Shannon- Weiner, Margalef and Jacardindics. The minimum and maximum values of Hilsenhoff biotic index were observedin stations 1 (4.29 and 5 (5.57, respectively. Moreover, the highest and lowest values of BMWP/ASPT were observed in station 1 (4.51 and 5 (3.25, respectively. Evaluation of indicators revealed less water quality at stations 2, 3 and 5 which located at the lowermost of fish farms and effluent of factory. This reduction might be implicated to the effluents of water damps from fish farms running into the stream as diversity and total abundance (% of sociable macroinvertebrates decreased and that of

  12. Analytical approaches used in stream benthic macroinvertebrate biomonitoring programs of State agencies in the United States (United States)

    Carter, James L.; Resh, Vincent H.


    Biomonitoring programs based on benthic macroinvertebrates are well-established worldwide. Their value, however, depends on the appropriateness of the analytical techniques used. All United States State, benthic macroinvertebrate biomonitoring programs were surveyed regarding the purposes of their programs, quality-assurance and quality-control procedures used, habitat and water-chemistry data collected, treatment of macroinvertebrate data prior to analysis, statistical methods used, and data-storage considerations. State regulatory mandates (59 percent of programs), biotic index development (17 percent), and Federal requirements (15 percent) were the most frequently reported purposes of State programs, with the specific tasks of satisfying the requirements for 305b/303d reports (89 percent), establishment and monitoring of total maximum daily loads, and developing biocriteria being the purposes most often mentioned. Most states establish reference sites (81 percent), but classify them using State-specific methods. The most often used technique for determining the appropriateness of a reference site was Best Professional Judgment (86 percent of these states). Macroinvertebrate samples are almost always collected by using a D-frame net, and duplicate samples are collected from approximately 10 percent of sites for quality assurance and quality control purposes. Most programs have macroinvertebrate samples processed by contractors (53 percent) and have identifications confirmed by a second taxonomist (85 percent). All States collect habitat data, with most using the Rapid Bioassessment Protocol visual-assessment approach, which requires ~1 h/site. Dissolved oxygen, pH, and conductivity are measured in more than 90 percent of programs. Wide variation exists in which taxa are excluded from analyses and the level of taxonomic resolution used. Species traits, such as functional feeding groups, are commonly used (96 percent), as are tolerance values for organic pollution


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    MARY N. J.


    Full Text Available Forty-one sites located on 14 New Caledonian streams were surveyed four times between October 1996 and October 1997 in order to examine the spatial and temporal changes in the structure of the benthic macroinvertebrate communities. About 250 000 invertebrates representing 167 taxa were collected in the streams. Seventy-five percent of identified taxa and 67% of individuals were insects. Major spatial and temporal changes in the composition of the fauna were detected by multivariate analyses (ordination and classification. Overall, the number of individuals was significantly higher in the dry season (October than in the wetter seasons (January and June. However, a low temporal variability was detected in the structure of benthic communities during the sampling period. A cluster analysis based on taxonomic composition separated five groups of sites in relation with rock type, land use, and geographic characteristics. Several metrics (total invertebrate density, taxon richness, relative abundance of major invertebrate groups, diversity indices were used to characterize each group of sites. Forested streams, where the highest specific diversity occurred, represented the most speciose habitat for benthic fauna. A less rich and abundant fauna occurred in streams draining ultramafic rocks probably because of their low content in food resources and organic matter.

  14. Application of Water Quality and Ecology Indices of Benthic Macroinvertebrate to Evaluate Water Quality of Tertiary Irrigation in Malang District

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    Desi Kartikasari


    Full Text Available This research aims to determine the water quality of tertiary irrigation in several subdistricts in Malang, namely Kepanjen, Karangploso, and Tumpang. The water quality depends on the water quality indices (National Sanitation Foundation’s-NSF Indices and O’Connor’s Indices based on variables TSS, TDS, pH, DO, and Nitrate concentrate and ecological indices of benthic macroinvertebrate (Diversity Indices Shannon-Wiener, Hilsenhof Biotic Indices-HBI, Average Score per Taxon-ASPT which is calculated by Biological Monitoring Working Party-BMWP, Ephemeroptera Indices, Plecoptera, Trichoptera-EPT. Observation of the physico-chemical water quality and benthic macroinvertebrate on May 2012 to April 2013. The sampling in each subdistrict was done at two selected stations in tertiary irrigation channel with three plot at each station. The data of physico-chemical quality of water were used to calculate the water quality indices, while the benthic macroinvertebrate data were used to calculate the ecological indices. The research findings showed that 27 taxa of benthic macroinvertebrates belong 10 classes were found in the three subdistrict. The pH, DO, Nitrate, TSS and TDS in six tertiary irrigation channels in Malang still met the water quality standards based on Government Regulation No. 82 of 2001 on Management of Water Quality and Water Pollution Control Class III. Based on NSF-WQI indices and O'Connor's Indices, water qualities in these irrigation channels were categorized into medium or moderate (yellow to good (green category. However, based on benthic macroinvertebrate communities which was used to determine the HBI, the water quality in the irrigation channels were categorized into the fair category (fairly significant organic pollution to fairly poor (significant organic pollution, while based on the value of ASPT, the water were categorized into probable moderate pollution to probable severe pollution. The irrigation water which was

  15. [Effects of benthic macro-invertebrate on decomposition of Acer buergerianum leaf litter in streams]. (United States)

    Jiang, Li-Hong; Wang, Bei-Xin; Chen, Ai-Qing; Lan, Ce-Jie


    By using composite mesh bag method, the effects of benthic macro-invertebrate in an undisturbed stream and an ecologically restored stream on the decomposition process of Acer buergerianum leaf litter from the Purple Mountain of Nanjing in winter were studied. After 112 days of decomposition, the remaining rate of A. buergerianum leaf litter based on ash-free dry mass was 31-62%, and the decomposition rate followed a declined exponential equation (P Shredders (mainly Asellus sp.) had the highest abundance (70.4%) in the flowing water of undisturbed stream, while filterers (mainly Tanytarsus sp.) were dominant (37.8%) in the flowing water of ecologically restored stream. The decomposition rate of the leaf litter was significantly correlated with the richness and abundance of shredder species in flowing water (P shredders, suggesting that the decomposition of A. buergerianum leaf litter in streams in winter was more dependent on the richness and abundance of shredders.

  16. Water Quality Assessment Using Benthic Macroinvertebrates in Saigon River and Its Tributaries, Vietnam

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    Duc Pham Anh


    Full Text Available This study to enhance the discussion about the usefulness of benthic macroinvertebrates for water quality assessment in Saigon River and its tributaries. Data from 16 sites were used as a representative example for Saigon River and its tributaries in the area of basin over 4,500 km2, the length through provinces of Tay Ninh, Binh Phuoc, Binh Duong, and Ho Chi Minh City of about 280 km. The data covered the period of dry and rainy seasons in 2015, the survey sampled 16 sites (32 events of the Saigon River and its tributaries selected. To implement this evaluation, the analyses were based on MRC methods and classifications these improved by the scientific group.

  17. Rapid integrated water quality evaluation of Mahisagar river using benthic macroinvertebrates. (United States)

    Bhadrecha, M H; Khatri, Nitasha; Tyagi, Sanjiv


    The water quality of Mahisagar river, near Galteshwar in Kheda district of Gujarat, India, was assessed through a rapid integrated technique by physicochemical parameters as well as benthic macroinvertebrates. Physicochemical parameters retrieved were pH, color, conductivity, total solids, total suspended solids, total dissolved solids, chlorides, total hardness, calcium hardness, magnesium hardness, alkalinity, turbidity, ammoniacal nitrogen, chemical oxygen demand, biochemical oxygen demand, dissolved oxygen, sulfates, and nitrates. The biological indices calculated were BMWP (Bio Monitoring Working Party) score or saprobic score and sequential comparison index or diversity score. In total, 37 families were encountered along the studied river stretch. The findings indicate that the water quality of Mahisagar river at sampled locations is “slightly polluted.” Moreover, the results of physicochemical analysis are also in consonance with the biological water quality criteria developed by Central Pollution Control Board.

  18. Linkages between nutrients and assemblages of macroinvertebrates and fish in wadeable streams: Implication to nutrient criteria development (United States)

    Wang, L.; Robertson, D.M.; Garrison, P.J.


    We sampled 240 wadeable streams across Wisconsin for different forms of phosphorus and nitrogen, and assemblages of macroinvertebrates and fish to (1) examine how macroinvertebrate and fish measures correlated with the nutrients; (2) quantify relationships between key biological measures and nutrient forms to identify potential threshold levels of nutrients to support nutrient criteria development; and (3) evaluate the importance of nutrients in influencing biological assemblages relative to other physicochemical factors at different spatial scales. Twenty-three of the 35 fish and 18 of the 26 macroinvertebrate measures significantly correlated (P < 0.05) with at least one nutrient measure. Percentages of carnivorous, intolerant, and omnivorous fishes, index of biotic integrity, and salmonid abundance were fish measures correlated with the most nutrient measures and had the highest correlation coefficients. Percentages of Ephemeroptera-Plecoptera-Trichoptera individuals and taxa, Hilsenhoff biotic index, and mean tolerance value were macroinvertebrate measures that most strongly correlated with the most nutrient measures. Selected biological measures showed clear trends toward degradation as concentrations of phosphorus and nitrogen increased, and some measures showed clear thresholds where biological measures changed drastically with small changes in nutrient concentrations. Our selected environmental factors explained 54% of the variation in the fish assemblages. Of this explained variance, 46% was attributed to catchment and instream habitat, 15% to nutrients, 3% to other water quality measures, and 36% to the interactions among all the environmental variables. Selected environmental factors explained 53% of the variation in macroinvertebrate assemblages. Of this explained variance, 42% was attributed to catchment and instream habitat, 22% to nutrients, 5% to other water quality measures, and 32% to the interactions among all the environmental variables. ?? 2006

  19. Spatial and temporal heterogeneity in a subtropical reservoir and their effects over the benthic macroinvertebrate community

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    Frederico Guilherme de Souza Beghelli


    Full Text Available AIM: The objective of the present study was to demonstrate the influences of the environment spatial heterogeneity on benthic macroinvertebrates considering transverse and longitudinal gradients as also seasonality. METHODS: Four samplings were performed: two in the wet and two in the dry season in the riverine, transitional and lacustrine zones in the littoral and profundal regions of Itupararanga reservoir, SP, Brazil. Abiotic characterization of the water and of the sediment was performed. The biotic characterization was based on richness, dominance, diversity, and density of organisms, as well as on the relative abundance of predominant taxa. Two-way ANOSIM analyses were performed for both biotic and abiotic components, in order to test the significance of the differences in the longitudinal and transverse directions as well as of the differences between seasons. RESULTS: Compartmentalization was present in both directions, longitudinal and transverse. In a general way, the littoral region presented higher diversity values when compared with the profundal region, and the riverine zone presented high densities and high percentage of taxons, which usually indicate organic pollution. The differentiation between the transitional and lacustrine zones was determined mainly by taxonomic composition. Seasonality was also observed and the transportation of small particles, the entrance of nutrients, and the presence of macrophytes were considered as determinants for differentiation. CONCLUSIONS: Together, these results demonstrate the responses of benthic macroinvertebrate communities considering distinct sources of variation: longitudinal heterogeneity, determined by the increasing distance from the forming rivers that leads to a gradient of physical and chemical conditions; transverse heterogeneity, determined by the proximity with the land environment and depth differences. Seasonal heterogeneity was recorded during the period of this research and

  20. Impacts of agricultural land use on stream benthic macroinvertebrates in tributaries of the Mekong River, northeast Thailand

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    Narumon Sangpradub


    Full Text Available Ecological impacts of non-intensive agricultural activities on stream community, especially inheadwater streams adjacent to conserved areas, are poorly known in Thailand. We investigated theimpacts of non-intensive agricultural activities on stream habitat characteristics and benthicmacroinvertebrate community in the headwater streams, tributaries of the Mekong River, northeastThailand. We compared the streams running through forests in National Parks and Wildlife Sanctuariesand those through agricultural areas. Twenty kick samples of benthic macroinvertebrates werecollected using a D-frame dipnet (0.3 m wide, 450 μm mesh size from each sampling site. Sixteenphysicochemical parameters of stream characteristics were measured. The results suggested that thisdisturbance had an impact on stream habitats more than its community. Agricultural land use alteredthe streams to be wider, deeper, and more discharged with less percentage of riparian coverage andhigh water temperature. Benthic macroinvertebrate composition did not differ in both areas, butintolerant benthic fauna decreased, while tolerant taxa were predominant and more abundant in theagricultural areas. In this study, water velocity and water temperature are the major importantvariables related to the distribution of benthic macroinvertebrates.

  1. Tolerance of benthic macroinvertebrates to organic enrichment in highland streams of northeastern Rio Grande do Sul, Brazil

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    Aline Correa Mazzoni


    Full Text Available AIM: the aim of this study was to determine the ecological valence of benthic macroinvertebrates at different pollution levels in highland rivers and streams of Rio Grande do Sul; METHODS: the dataset proceeds from samplings performed between 2002-2011 in 35 lotic ecosystems. The Chemical Index was used to determine pollution levels. Indices of richness and Shannon diversity were applied to characterize the structure of benthic communities. The descriptors used to determine taxa's ecological valence were selected according to Coefficient of Variation and regression analyses. Groups of tolerance were identified using Interquartile range and cluster analysis; RESULTS: Conductivity and Chemical Index were the descriptors best related with diversity of benthic macroinvertebrate community. These metrics were used to determine the tolerance range of 38 taxa. Interquartile range and cluster analysis revealed three groups of taxa, according to their occurrence in different levels of pollution: taxa with narrow amplitudes, present at sites with very low or very high load of organic enrichment; taxa with moderate amplitude, found until moderately polluted sites; and taxa with occurrence in widespread environmental conditions. The results, when compared to other studies in Brazil, showed differences in some taxa's tolerance. This observation indicates the need to assess the bioindication potential of these taxa in genus and species level; CONCLUSION: the present study contributes to increase knowledge about the bioindicator potential of benthic macroinvertebrates. Therefore, the study supports an advanced biomonitoring of ecological quality in mountain streams of southern Brazil.

  2. Does water level affect benthic macro-invertebrates of a marginal lake in a tropical river-reservoir transition zone? (United States)

    Zerlin, R A; Henry, R


    Benthic macro-invertebrates are important components of freshwater ecosystems which are involved in ecological processes such as energy transfer between detritus and consumers and organic matter recycling. The aim of this work was to investigate the variation in organism richness, diversity and density of benthic fauna during the annual cycle in Camargo Lake, a lake marginal to Paranapanema River, southeast Brazil. The correlation of environmental factors with community attributes of the macro-benthic fauna was assessed. Since Camargo Lake is connected to the river, we tested the hypothesis that water level variation is the main regulating factor of environmental variables and of the composition and abundance of benthic macro-invertebrates. The results indicated that lake depth varied with rainfall, being the highest at the end of the rising water period and the lowest at the beginning of this period. The sediment granulometry was more heterogeneous at the bottom of the lake by the end of the high water period. The benthic macro-invertebrate fauna was composed by 15 taxa. The Diptera order was represented by seven taxa and had greater richness in relation to other taxa. This group was responsible for 60% of the total abundance of organisms, followed by Ephemeroptera (22%) and Anellida (16%). Significant differences were observed over time in total richness and, in density of Narapa bonettoi, Chaoborus, Ablabesmyia gr. annulata, Chironomus gigas, Larsia fittkau, and Procladius sp. 2. Total taxa richness correlated negatively with water pH, transparency, conductivity, and bottom water oxygen. Higher positive correlations were found between the densities of some taxa and bottom water oxygen, conductivity and very fine sand, silt + clay of sediment, while negative correlations were recorded with organic matter, and fine, medium and coarse sand, bottom water temperature, mean temperature and rainfall. The significant temporal difference in water level was associated

  3. Macroinvertebrate assemblages and biodiversity levels: ecological role of constructed wetlands and artificial ponds in a natural park

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    Laura Sartori


    Full Text Available Normal 0 14 false false false MicrosoftInternetExplorer4 Constructed wetlands play an important role in water supply, floodwater retention and nutrient removal, at the same time allowing the restoration of lost habitat and the preservation of biodiversity. There is little knowledge about the biodiversity that can be found in these artificial environments along time, especially at the invertebrate community level. Macroinvertebrate assemblages, water chemistry, morphology, and environmental characteristics of natural ponds, artificial pools and constructed wetlands in Parco Pineta (Northern Italy were studied to evaluate the effects of local factors on macroinvertebrate communities. The objective was to verify if each ecosystem could equally contribute to local biodiversity, regardless of its natural or artificial origin. Principal Components Analysis showed that ponds were divided into clusters, based on their morphology and their water quality, independently from their origin. The composition of macroinvertebrate communities was similar among natural wetlands and ponds artificially created to provide new habitats in the park, while it was different among natural wetlands and constructed wetlands created for wastewater treatment purposes. Biodiversity of natural ponds and constructed wetlands, evaluated using taxa richness, Shannon index, and Pielou index, was comparable. Canonical Correspondence Analysis highlighted differences in macroinvertebrate community composition and pointed out the relationships among macroinvertebrates and various environmental variables: habitat heterogeneity resulted as the most relevant factor that influences taxa richness. Water quality also affects the macroinvertebrate community structure. We determined that constructed wetlands with higher pollutant concentrations show different assemblage compositions but comparable overall macroinvertebrate biodiversity. Constructed wetlands became valuable ecological elements

  4. Use of Benthic Macroinvertebrates to Evaluate Stream Water Quality in Trinidad and Tobago, West Indies (United States)

    Maharaj, L. D.; Alkins-Koo, M.


    In order to determine the best method of using benthic macroinvertebrates to monitor water quality in Trinidad and Tobago, 63 sites along 38 streams were sampled in each of the wet and dry seasons from 1999-2001. At each site, 5 benthic samples were collected with a 300μm 'D' frame kicknet, along with data for 14 environmental parameters and habitat data. Principal Components Analyses separated the streams into 3 ecoregions based on substrate type and discharge. Using ANOVA, mean values for each environmental parameter were compared across each ecoregion. Values of dissolved Oxygen, BOD-5, nitrates, total suspended solids and pH varied significantly during the wet season, while dissolved Oxygen, pH and chlorophyll-a varied significantly during the dry. Using PRIMER version 5, non-metric multi-dimensional scaling and cluster analyses were performed on the faunal data for each ecoregion separately and for all sites combined. These analyses indicate that the fauna associated with minimally, moderately and severely impaired sites is similar across all 3 ecoregions. Of the different metrics compared during the study, a modified version of the Average Score Per Taxon (ASPT) best fit the clusters were produced.

  5. Natural disturbance shapes benthic intertidal macroinvertebrate communities of high latitude river deltas (United States)

    Churchwell, Roy T.; Kendall, Steve J.; Blanchard, Amy L.; Dunton, Kenneth H.; Powell, Abby N.


    Unlike lower latitude coastlines, the estuarine nearshore zones of the Alaskan Beaufort Sea are icebound and frozen up to 9 months annually. This annual freezing event represents a dramatic physical disturbance to fauna living within intertidal sediments. The main objectives of this study were to describe the benthic communities of Beaufort Sea deltas, including temporal changes and trophic structure. Understanding benthic invertebrate communities provided a baseline for concurrent research on shorebird foraging ecology at these sites. We found that despite continuous year-to-year episodes of annual freezing, these estuarine deltas are populated by a range of invertebrates that represent both marine and freshwater assemblages. Freshwater organisms like Diptera and Oligochaeta not only survive this extreme event, but a marine invasion of infaunal organisms such as Amphipoda and Polychaeta rapidly recolonizes the delta mudflats following ice ablation. These delta sediments of sand, silt, and clay are fine in structure compared to sediments of other Beaufort Sea coastal intertidal habitats. The relatively depauperate invertebrate community that ultimately develops is composed of marine and freshwater benthic invertebrates. The composition of the infauna also reflects two strategies that make life on Beaufort Sea deltas possible: a migration of marine organisms from deeper lagoons to the intertidal and freshwater biota that survive the 9-month ice-covered period in frozen sediments. Stable isotopic analyses reveal that both infaunal assemblages assimilate marine and terrestrial sources of organic carbon. These results provide some of the first quantitative information on the infaunal food resources of shallow arctic estuarine systems and the long-term persistence of these invertebrate assemblages. Our data help explain the presence of large numbers of shorebirds in these habitats during the brief summer open-water period and their trophic importance to migrating

  6. Impact assessment of agricultural driven stressors on benthic macroinvertebrates using simulated data. (United States)

    Stefanidis, K; Panagopoulos, Y; Mimikou, M


    Agricultural land use poses a significant threat to the ecological integrity of rivers in Europe. Particularly in the Mediterranean, water abstraction and nutrient application are anthropogenic pressures that have a significant impact on aquatic habitats and biodiversity. In this article, we assessed the effects of agricultural management practices on benthic macroinvertebrates in a large river basin of central Greece using simulated data based on the application of SWAT (Soil Water Assessment Tool) model. Physicochemical and hydrological output variables of the model were used as predictors of the ASPT (Average Score Per Taxon) metric based on a correlated component regression analysis (CCR) built on empirical data. The estimation of ASPT was performed for the wet and dry seasons within a 20-year period for a total of 47 subbasins under the baseline conditions and after implementing three management scenarios that reduced: a) irrigation water applied to crops by 30%, b) chemical fertilization applied to crops by 30% and c) both irrigation and fertilization by 30%. The results revealed that application of the reduced irrigation resulted to a slight increase of the simulated dissolved inorganic nitrogen concentration (DIN), which in turn decreased the mean ASPT in 21 of the 47 subbasins implying a negative effect on the macroinvertebrate communities. On the contrary, the reduction of fertilization as well as the combined scenario decreased both the simulated DIN and phosphate concentration causing an increase of the mean ASPT for a total of 40 of the 47 subbasins. Based on these results, we suggest that the best management option is a combined practice of deficit irrigation and fertilization reduction since it improved water quality, increased ASPT values and saved a considerable amount of water. Overall, this work demonstrates a simple methodology that can efficiently assess the effects of agricultural management practices on biotic indicators.

  7. An evaluation of the relative quality of dike pools for benthic macroinvertebrates in the Lower Missouri River, USA (United States)

    Poulton, B.C.; Allert, A.L.


    A habitat-based aquatic macroinvertebrate study was initiated in the Lower Missouri River to evaluate relative quality and biological condition of dike pool habitats. Water-quality and sediment-quality parameters and macroinvertebrate assemblage structure were measured from depositional substrates at 18 sites. Sediment porewater was analysed for ammonia, sulphide, pH and oxidation-reduction potential. Whole sediments were analysed for particle-size distribution, organic carbon and contaminants. Field water-quality parameters were measured at subsurface and at the sediment-water interface. Pool area adjacent and downstream from each dike was estimated from aerial photography. Macroinvertebrate biotic condition scores were determined by integrating the following indicator response metrics: % of Ephemeroptera (mayflies), % of Oligochaeta worms, Shannon Diversity Index and total taxa richness. Regression models were developed for predicting macroinvertebrate scores based on individual water-quality and sediment-quality variables and a water/sediment-quality score that integrated all variables. Macroinvertebrate scores generated significant determination coefficients with dike pool area (R2=0.56), oxidation–reduction potential (R2=0.81) and water/sediment-quality score (R2=0.71). Dissolved oxygen saturation, oxidation-reduction potential and total ammonia in sediment porewater were most important in explaining variation in macroinvertebrate scores. The best two-variable regression models included dike pool size + the water/sediment-quality score (R2=0.84) and dike pool size + oxidation-reduction potential (R2=0.93). Results indicate that dike pool size and chemistry of sediments and overlying water can be used to evaluate dike pool quality and identify environmental conditions necessary for optimizing diversity and productivity of important aquatic macroinvertebrates. A combination of these variables could be utilized for measuring the success of habitat enhancement

  8. A Multimetric Benthic Macroinvertebrate Index for the Assessment of Stream Biotic Integrity in Korea

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    Soon-Jin Hwang


    Full Text Available At a time when anthropogenic activities are increasingly disturbing the overall ecological integrity of freshwater ecosystems, monitoring of biological communities is central to assessing the health and function of streams. This study aimed to use a large nation-wide database to develop a multimetric index (the Korean Benthic macroinvertebrate Index of Biological Integrity—KB-IBI applicable to the biological assessment of Korean streams. Reference and impaired conditions were determined based on watershed, chemical and physical criteria. Eight of an initial 34 candidate metrics were selected using a stepwise procedure that evaluated metric variability, redundancy, sensitivity and responsiveness to environmental gradients. The selected metrics were number of taxa, percent Ephemeroptera-Plecoptera-Trichoptera (EPT individuals, percent of a dominant taxon, percent taxa abundance without Chironomidae, Shannon’s diversity index, percent gatherer individuals, ratio of filterers and scrapers, and the Korean saprobic index. Our multimetric index successfully distinguished reference from impaired conditions. A scoring system was established for each core metric using its quartile range and response to anthropogenic disturbances. The multimetric index was classified by aggregating the individual metric ..scores and the value range was quadrisected to provide a narrative criterion (Poor, Fair, Good and Excellent to describe the biological integrity of the streams in the study. A validation procedure showed that the index is an effective method for evaluating stream conditions, and thus is appropriate for use in future studies measuring the long-term status of streams, and the effectiveness of restoration methods.

  9. Inferring community properties of benthic macroinvertebrates in streams using Shannon index and exergy (United States)

    Nguyen, Tuyen Van; Cho, Woon-Seok; Kim, Hungsoo; Jung, Il Hyo; Kim, YongKuk; Chon, Tae-Soo


    Definition of ecological integrity based on community analysis has long been a critical issue in risk assessment for sustainable ecosystem management. In this work, two indices (i.e., Shannon index and exergy) were selected for the analysis of community properties of benthic macroinvertebrate community in streams in Korea. For this purpose, the means and variances of both indices were analyzed. The results found an extra scope of structural and functional properties in communities in response to environmental variabilities and anthropogenic disturbances. The combination of these two parameters (four indices) was feasible in identification of disturbance agents (e.g., industrial pollution or organic pollution) and specifying states of communities. The four-aforementioned parameters (means and variances of Shannon index and exergy) were further used as input data in a self-organizing map for the characterization of water quality. Our results suggested that Shannon index and exergy in combination could be utilized as a suitable reference system and would be an efficient tool for assessment of the health of aquatic ecosystems exposed to environmental disturbances.

  10. Effects of organic pollution and physical stress on benthic macroinvertebrate communities from two intermittently closed and open coastal lagoons (ICOLLs) (United States)

    Coelho, Susana; Pérez-Ruzafa, Angel; Gamito, Sofia


    Benthic macroinvertebrate communities and environmental conditions were studied in two intermittently closed and open coastal lakes and lagoons (ICOLLs), located in southern Algarve (Foz do Almargem e Salgados), with the purpose of evaluating the effects of organic pollution, originated mainly from wastewater discharges, and the physical stress caused by the irregular opening of the lagoons. Most of the year, lagoons were isolated from the sea, receiving the freshwater inputs from small rivers and in Salgados, also from the effluents of a wastewater plant. According to environmental and biotic conditions, Foz do Almargem presented a greater marine influence and a lower trophic state (mesotrophic) than Salgados (hypereutrophic). Benthic macroinvertebrate communities in the lagoons were distinct, just as their relations with environmental parameters. Mollusca were the most abundant macroinvertebrates in Foz do Almargem, while Insecta, Oligochaeta and Crustacea were more relevant in Salgados. Corophium multisetosum occurred exclusively in Salgados stations and, just as Chironomus sp., other Insecta and Oligochaeta, densities were positively related to total phosphorus, clay content and chlorophyll a concentration in the sediment, chlorophyll a concentration in water and with total dissolved inorganic nitrogen. Abra segmentum, Cerastoderma glaucum, Peringia ulvae and Ecrobia ventrosa occurred only in Foz do Almargem, with lower values of the above mentioned parameters. Both lagoons were dominated by deposit feeders and taxa tolerant to environmental stress, although in Salgados there was a greater occurrence of opportunistic taxa associated to pronounced unbalanced situations, due to excess organic matter enrichment.

  11. Predicting ecological changes on benthic estuarine assemblages through decadal climate trends along Brazilian Marine Ecoregions (United States)

    Bernardino, Angelo F.; Netto, Sérgio A.; Pagliosa, Paulo R.; Barros, Francisco; Christofoletti, Ronaldo A.; Rosa Filho, José S.; Colling, André; Lana, Paulo C.


    Estuaries are threatened coastal ecosystems that support relevant ecological functions worldwide. The predicted global climate changes demand actions to understand, anticipate and avoid further damage to estuarine habitats. In this study we reviewed data on polychaete assemblages, as a surrogate for overall benthic communities, from 51 estuaries along five Marine Ecoregions of Brazil (Amazonia, NE Brazil, E Brazil, SE Brazil and Rio Grande). We critically evaluated the adaptive capacity and ultimately the resilience to decadal changes in temperature and rainfall of the polychaete assemblages. As a support for theoretical predictions on changes linked to global warming we compared the variability of benthic assemblages across the ecoregions with a 40-year time series of temperature and rainfall data. We found a significant upward trend in temperature during the last four decades at all marine ecoregions of Brazil, while rainfall increase was restricted to the SE Brazil ecoregion. Benthic assemblages and climate trends varied significantly among and within ecoregions. The high variability in climate patterns in estuaries within the same ecoregion may lead to correspondingly high levels of noise on the expected responses of benthic fauna. Nonetheless, we expect changes in community structure and productivity of benthic species at marine ecoregions under increasing influence of higher temperatures, extreme events and pollution.

  12. Biological Assessment of Aquaculture Effects on Effluent-Receiving Streams in Ghana Using Structural and Functional Composition of Fish and Macroinvertebrate Assemblages (United States)

    Ansah, Yaw Boamah; Frimpong, Emmanuel A.; Amisah, Stephen


    Biological assessment of aquatic ecosystems is widely employed as an alternative or complement to chemical and toxicity testing due to numerous advantages of using biota to determine ecosystem condition. These advantages, especially to developing countries, include the relatively low cost and technical requirements. This study was conducted to determine the biological impacts of aquaculture operations on effluent-receiving streams in the Ashanti Region of Ghana. We collected water, fish and benthic macroinvertebrate samples from 12 aquaculture effluent-receiving streams upstream and downstream of fish farms and 12 reference streams between May and August of 2009, and then calculated structural and functional metrics for biotic assemblages. Fish species with non-guarding mode of reproduction were more abundant in reference streams than downstream ( P = 0.0214) and upstream ( P = 0.0251), and sand-detritus spawning fish were less predominant in reference stream than upstream ( P = 0.0222) and marginally less in downstream locations ( P = 0.0539). A possible subsidy-stress response of macroinvertebrate family richness and abundance was also observed, with nutrient (nitrogen) augmentation from aquaculture and other farming activities likely. Generally, there were no, or only marginal differences among locations downstream and upstream of fish farms and in reference streams in terms of several other biotic metrics considered. Therefore, the scale of impact in the future will depend not only on the management of nutrient augmentation from pond effluents, but also on the consideration of nutrient discharges from other industries like fruit and vegetable farming within the study area.

  13. Towards a multimetric index for the assessment of Dutch streams using benthic macroinvertebrates

    NARCIS (Netherlands)

    Vlek, H.E.; Verdonschot, P.F.M.; Nijboer, R.C.


    This study describes the development of a macroinvertebrate based multimetric index for two stream types, fast and slow running streams, in the Netherlands within the AQEM project. Existing macroinvertebrate data (949 samples) were collected from these stream types from all over the Netherlands. All

  14. Macroinvertebrate assemblages and secondary production in three wood-poor, second-growth, headwater streams in the Upper Peninsula of Michigan. (United States)

    Entrekin, S. A.; Rosi-Marshall, E. J.; Tank, J. L.; Lamberti, G. A.


    Benthic organic matter (BOM) is retained by in-stream wood in forested streams and is often the primary food resource for aquatic macroinvertebrates. We sampled BOM and macroinvertebrates in three, forested headwater streams within the same watershed and predicted that BOM standing stocks would be high and, therefore, macroinvertebrate functional feeding groups would be dominated by shredders and gatherers. However, all streams had low annual average standing stocks of BOM (75 to 166 gAFDM m-2), and low shredder biomass (bryophytes for food and habitat. We conclude that macroinvertebrate communities in these streams are limited by BOM that was not retained in-stream because of reduced wood inputs from past logging.

  15. Abundance and distribution of benthic macroinvertebrates in offshore soft sediments in Western Lake Huron, 2001-2007 (United States)

    French, J. R. P.; Schaeffer, J.S.; Roseman, E.F.; Kiley, C.S.; Fouilleroux, A.


    Invasive species have had major impacts on the Great Lakes. This is especially true of exotic dreissenid mussels which are associated with decreased abundance of native macroinvertebrates and changes in food availability for fish. Beginning in 2001, we added a benthic macroinvertebrate survey to the USGS-Great Lakes Science Center's annual fall prey fish assessment of Lake Huron to monitor abundance of macrobenthos. Mean abundance of Diporeia, the most abundant benthic taxon in Lake Huron reported by previous investigators, declined greatly between 2001 and 2007. Diporeia was virtually absent at 27-m sites by 2001, decreased and was lost completely from 46-m depths by 2006, but remained present at reduced densities at 73-m sites. Dreissenids in our samples were almost entirely quagga mussels Dreissena bugensis. Zebra mussels Dreissena polymorpha were virtually absent from our samples, suggesting that they were confined to nearshore areas shallower than we sampled. Loss of Diporeia at individual sites was associated with arrival of quagga mussels, even when mussel densities were low. Quagga mussel density peaked during 2002, then decreased thereafter. During the study quagga mussels became established at most 46-m sites, but remained rare at 73-m sites. Length frequency distributions suggest that initial widespread recruitment may have occurred during 2001-2002. Like other Great Lakes, Lake Huron quagga mussels were associated with decreased abundance of native taxa, but negative effects occurred even though dreissenid densities were much lower. Dreissenid effects may extend well into deep oligotrophic habitats of Lake Huron.

  16. Assessment of Streamside Management Zones for Conserving Benthic Macroinvertebrate Communities Following Timber Harvest in Eastern Kentucky Headwater Catchments

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    Joshua K. Adkins


    Full Text Available Headwater streams generally comprise the majority of stream area in a watershed and can have a strong influence on downstream food webs. Our objective was to determine the effect of altering streamside management zone (SMZ configurations on headwater aquatic insect communities. Timber harvests were implemented within six watersheds in eastern Kentucky. The SMZ configurations varied in width, canopy retention and best management practice (BMP utilization at the watershed scale. Benthic macroinvertebrate samples collected one year before and four years after harvest indicated few differences among treatments, although post-treatment abundance was elevated in some of the treatment streams relative to the unharvested controls. Jaccard index values were similar across SMZ treatments after logging, indicating strong community overlap. These findings suggest that stream invertebrate communities did respond to the timber harvest, though not negatively. Results also suggest that SMZ criteria for aquatic habitats in steeply sloping topography, including at least 50 percent canopy retention and widths of at least 16.8 m, appear to be adequate for protecting benthic macroinvertebrate communities from logging impacts.

  17. Aquatic macroinvertebrate assemblages of Ghana, West Africa: understanding the ecology of a neglected tropical disease. (United States)

    Eric Benbow, M; Kimbirauskas, Ryan; McIntosh, Mollie D; Williamson, Heather; Quaye, Charles; Boakye, Daniel; Small, Pamela L C; Merritt, Richard W


    Buruli ulcer (BU) is an emerging, but neglected tropical disease, where there has been a reported association with disturbed aquatic habitats and proposed aquatic macroinvertebrate vectors such as biting Hemiptera. An initial step in understanding the potential role of macroinvertebrates in the ecology of BU is to better understand the entire community, not just one or two taxa, in relation to the pathogen, Mycobacterium ulcerans, at a large spatial scale. For the first time at a country-wide scale this research documents that M. ulcerans was frequently detected from environmental samples taken from BU endemic regions, but was not present in 30 waterbodies of a non-endemic region. There were significant differences in macroinvertebrate community structure and identified potential indicator taxa in relation to pathogen presence. These results suggest that specific macroinvertebrate taxa or functional metrics may potentially be used as aquatic biological indicators of M. ulcerans. Developing ecological indicators of this pathogen is a first step for understanding the disease ecology of BU and should assist future studies of transmission.

  18. Environmental and spatial controls of macroinvertebrate functional assemblages in seagrass ecosystems along the Pacific coast of northern Japan

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    Katsumasa Yamada


    Full Text Available The relative contributions of environmental and spatial processes in macroinvertebrate community structure (i.e.,  β-diversity for three functional groups classified on the basis of dispersal ability and microhabitat selection (seagrass-associated [SA], drift-faunal [DF], and benthic-faunal [BF] groups were examined in a seagrass ecosystem along the Sanriku coast of Japan. Variation partitioning was conducted to explain the environmental heterogeneity and spatial arrangement of local communities (i.e., degree of variation in the community for each functional group. Processes determining community structure and metacommunity type differed among the functional groups. The SA group was under greater influence of environmental control, whereas the fractions of β-diversity in the DF and BF groups were explained by only spatial predictors. Thus, even if macroinvertebrate communities live in the same ecosystem, different mechanisms may determine the functional community structure, which depends on ecological traits such as dispersal ability and microhabitat. Ecological processes underlying community assembly differ among functional groups, indicating that the existence and/or dynamics of seagrass patches may affect the variation of faunal functions in an ecosystem.

  19. In situ effects of titanium dioxide nanoparticles on community structure of freshwater benthic macroinvertebrates. (United States)

    Jovanović, Boris; Milošević, Djuradj; Piperac, Milica Stojković; Savić, Ana


    For the first time in the current literature, the effect of titanium dioxide (TiO2) nanoparticles on the community structure of macroinvertebrates has been investigated in situ. Macroinvertebrates were exposed for 100 days to an environmentally relevant concentration of TiO2 nanoparticles, 25 mg kg(-1) in sediment. Czekanowski's index was 0.61, meaning 39% of the macroinvertebrate community structure was affected by the TiO2 treatment. Non-metric multidimensional scaling (NMDS) visualized the qualitative and quantitative variability of macroinvertebrates at the community level among all samples. A distance-based permutational multivariate analysis of variance (PERMANOVA) revealed the significant effect of TiO2 on the macroinvertebrate community structure. The indicator value analysis showed that the relative frequency and abundance of Planorbarius corneus and Radix labiata were significantly lower in the TiO2 treatment than in the control. Meanwhile, Ceratopogonidae, showed a significantly higher relative frequency and abundance in the TiO2 treatment than in the control.

  20. Processes of benthic foraminiferal fossil assemblage formation on the continental slope

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    Loubere, P. (Northern Illinois Univ., DeKalb (United States))


    Theoretical analysis of benethic foraminiferal fossil assemblage formation shows that the assemblage eventually preserved in the sediments is an integrated result of species' test production rate, microhabitat behavior, and biogeochemical processes that control the probability of species' test preservation. The biogeochemical processes that influence test preservation in slope sediments are controlled by the flux of organic carbon to the sea-bed and the botton water oxygen concentration. These variables also affect the depth of the biotic habitation zone in the sediments. Therefore, organic carbon flux and bottom water oxygen content should be reflected in benthic foraminiferal fossil assemblages for both ecologic and taphonomic reasons. An integrated study of fossil assemblage generation was conducted on the Gulf of Mexico continental slope using box cores collected along depth transects across the oxygen minimum, and using live and dead assemblage analysis combined with {sup 210}Pb measurements to quantify biotic activity in the sediments and pore water nutrient and metals analysis to quantify biogeochemical processes acting in the sediment habitation zone. The results show that the size of the habitation zone and live standing stock are influenced by organic carbon flux and oxygen supply to the sea-bed. The fossil assemblage is created progressively through the upper 10-20 cm of sediment and biologichemically driven test destruction (taphonomic process) is important in determining the assemblage that enters the geologic record.


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    Elena Daniela MITITELU


    Full Text Available The wide distribution of benthic invertebrates and their different sensitivity shown upon modifying the qualitative parameters of aquatic ecosystems led to a frequent use of these group as bioindicators in different studies. The present study aims at presenting a list concerning the different macroinvertebrates identified in the larva stage in three watersheds (Jiu, Olt, Ialomiţa and establishing the water quality of the monitored sections using this benthic macroinvertebrates. The sample collecting points were represented by 23 stations. The abundance and frequency values recorded for benthic communities varied according to the physical-chemical conditions specific to each sample collecting station. There were identified 15 groups in total. The most frequent were Ephemeroptera, Plecoptera, Trichoptera, Diptera (Chironomidae and others. The deterioration of water quality is marked by the decrease in the biotic index EPT/Ch value.

  2. Benthic Macroinvertebrate Communities in the Northern Tributaries of the “Iron Gates” Gorge (Danube River

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    Curtean-Bănăduc Angela


    Full Text Available The paper presents the structure of the benthonic macro-invertebrates communities in the Berzasca, Sirinia, Liubcova, and Mraconia rivers. The results are based on quantitative benthos samples (95 samples, collected in July 2014 from 19 sampling stations within the study area. In longitudinal profile, the benthonic macro-invertebrate communities of the Sirinia, Liubcova and Berzasca rivers displays relatively large structural variability, while the communities of the Mraconia River displays smaller structural variability. The structure of the benthonic macro-invertebrate communities correlated with the biotope characteristics indicates the good ecological status of the analysed rivers, with the exception of the Berzasca River sector downstream of the town of Berzasca and immediately upstream of the Danube junction, a sector with moderate ecological status due to negative effects from man-made modifications in the lotic biotope of the sector.

  3. Bathymetric and regional changes in benthic macrofaunal assemblages on the deep Eastern Brazilian margin, SW Atlantic (United States)

    Bernardino, Angelo Fraga; Berenguer, Vanessa; Ribeiro-Ferreira, Venina P.


    Deep-sea continental slopes have valuable mineral and biological resources in close proximity to diverse, undersampled and fragile marine benthic ecosystems. The eastern Brazilian Continental Margin (19.01°S to 21.06°S, 37.88°W to 40.22°W) is an important economic region for both fishing and oil industries, but is poorly understood with respect to the structure of the soft-sediment benthic fauna, their regional distribution and their bathymetric patterns. To identify spatial and temporal patterns of benthic macrofaunal assemblages on the slope (400 to 3000 m), the Espirito Santo Basin Assessment Project (AMBES, coordinated by Cenpes-Petrobras) sampled 42 stations across the Brazilian Eastern Slope during both Summer 2012 and Winter 2013. We found a significant decrease in macrofaunal abundance at the 400 m isobath along the slope near the northern region of the Espirito Santo Basin, suggesting benthic responses to upwelling events towards the south in Campos Basin and southern Espirito Santo Basin. The taxonomic diversity and assemblage composition also changed significantly across depth zones with mid-slope peaks of diversity at 1000-1300 m. In general, macrofaunal assemblages were strongly related to slope depth, suggesting a strong influence of productivity gradients and water mass distribution on this oligotrophic margin. Sediment grain size was marginally important to macrofaunal composition on the upper slope. In general, macrofaunal assemblages on the slope of Espirito Santo Basin are similar to other areas of the SE Brazilian margin, but regional changes in response to productivity and depth need to be considered for management strategies in the face of increasing economic activities off-shore.

  4. Multiple stress response of lowland stream benthic macroinvertebrates is dependent on habitat type

    DEFF Research Database (Denmark)

    Graeber, Daniel; Jensen, Tinna M.; Rasmussen, Jes


    , an effect which was reduced by fine sedimentation for the dominant shredder species (Gammarus pulex) and by nutrient enrichment for the dominating grazer species (Baetis rhodani). In contrast, fine sediment in combination with low flow rapidly affected macroinvertebrate composition in the run habitat...

  5. Evaluating ethanol-based sample preservation to facilitate use of DNA barcoding in routine freshwater biomonitoring programs using benthic macroinvertebrates.

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    Eric D Stein

    Full Text Available Molecular methods, such as DNA barcoding, have the potential to enhance biomonitoring programs worldwide. Altering routinely used sample preservation methods to protect DNA from degradation may pose a potential impediment to application of DNA barcoding and metagenomics for biomonitoring using benthic macroinvertebrates. Using higher volumes or concentrations of ethanol, requirements for shorter holding times, or the need to include additional filtering may increase cost and logistical constraints to existing biomonitoring programs. To address this issue we evaluated the efficacy of various ethanol-based sample preservation methods at maintaining DNA integrity. We evaluated a series of methods that were minimally modified from typical field protocols in order to identify an approach that can be readily incorporated into existing monitoring programs. Benthic macroinvertebrates were collected from a minimally disturbed stream in southern California, USA and subjected to one of six preservation treatments. Ten individuals from five taxa were selected from each treatment and processed to produce DNA barcodes from the mitochondrial gene cytochrome c oxidase I (COI. On average, we obtained successful COI sequences (i.e. either full or partial barcodes for between 93-99% of all specimens across all six treatments. As long as samples were initially preserved in 95% ethanol, successful sequencing of COI barcodes was not affected by a low dilution ratio of 2∶1, transfer to 70% ethanol, presence of abundant organic matter, or holding times of up to six months. Barcoding success varied by taxa, with Leptohyphidae (Ephemeroptera producing the lowest barcode success rate, most likely due to poor PCR primer efficiency. Differential barcoding success rates have the potential to introduce spurious results. However, routine preservation methods can largely be used without adverse effects on DNA integrity.

  6. Abundance, size composition and benthic assemblages of two Mediterranean echinoids off the

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    Elzahrae Elmasry


    Full Text Available This study is concerned with the variability in abundance, size composition and benthic assemblages of two echinoid species, the common sea urchin Paracentrotus lividus (Lamarck, 1816 and black urchin Arbacia lixula (Linnaeus, 1758 in the Southeastern Mediterranean (SEM along the coast of Alexandria, Egypt. Four seasonal trips were made during the years 2014–2015 covering 55 km of the shore with depths ranging between 3 and 9 m. The sea urchin species composition, density and size structure and distribution were compared. The associated macrobenthic invertebrates with prominent presence and biomass were observed as well as other benthic fauna and flora associations. The present results showed that P. lividus was the dominant echinoid spatially and temporally. A. lixula showed frequent occurrence in Sidi Bishr and Sidi Gaber stations in the spring season. The most dominant size class was the medium to large-sized classes for P. lividus and large-sized classes for A. lixula. The commercial size for the edible P. lividus represented 33% of the sampled population. Furthermore, the most dominant macrobenthic assemblages beside the echinoid population were primarily oysters, sea cucumbers, and mussels. Beside these, assemblage of seaweeds (red, green, brown and crustose algae, Porifera, Cnidaria, Crustacea, other Echinodermata, Bivalvia, Gastropoda, Tunicata, Bryozoa and Annelida were found. The present study shows that the investigated area represents stable habitats for the echinoid population with rich and diversified algal assemblages as well as other potential food resources.

  7. Abiotic proxies for predictive mapping of near-shore benthic assemblages: Implications for marine spatial planning. (United States)

    McHenry, Jennifer; Steneck, Robert S; Brady, Damian C


    Marine spatial planning (MSP) should assist managers in guiding human activities towards sustainable practices and in minimizing user-conflicts in our oceans. A necessary first step is to quantify spatial patterns of marine assemblages in order to understand the ecosystem's structure, function, and services. However, the large spatial scale, high economic value, and density of human activities in near-shore habitats often makes quantifying this component of marine ecosystems especially daunting. To address this challenge, we developed an assessment method that employs abiotic proxies to rapidly characterize marine assemblages in near-shore benthic environments with relatively high resolution. We evaluated this assessment method along 300 km of the State of Maine's coastal shelf (spatial extrapolations of marine assemblages in congested (heavily used) near-shore habitats. This article is protected by copyright. All rights reserved.

  8. Relationship between 'live' and dead benthic foraminiferal assemblages in the abyssal NE Atlantic (United States)

    Stefanoudis, Paris V.; Bett, Brian J.; Gooday, Andrew J.


    Dead foraminiferal assemblages within the sediment mixed layer provide an integrated, time-averaged view of the foraminiferal fauna, while the relationship between dead and live assemblages reflects the population dynamics of different species together with taphonomic processes operating over the last few hundred years. Here, we analysed four samples for 'live' (Rose-Bengal-stained) and dead benthic foraminifera (0-1 cm sediment layer, >150 μm) from four sites in the area of the Porcupine Abyssal Plain Sustained Observatory (PAP-SO; NE Atlantic, 4850 m water depth). Two sites were located on abyssal hills and two on the adjacent abyssal plain. Our results indicate that the transition from live to dead benthic foraminiferal assemblages involved a dramatic loss of delicate agglutinated and organic-walled tests (e.g. Lagenammina, Nodellum, Reophax) with poor preservation potential, and to a lesser extent that of some relatively fragile calcareous tests (mostly miliolids), possibly a result of dissolution. Other processes, such as the transport of tests by bottom currents and predation, are unlikely to have substantially altered the composition of dead faunas. Positive live to dead ratios suggest that some species (notably Epistominella exigua and Bolivina spathulata) may have responded to recent phytodetritus input. Although the composition of live assemblages seemed to be influenced by seafloor topography (abyssal hills vs. plain), no such relation was found for dead assemblages. We suggest that PAP-SO fossil assemblages are likely to be comparable across topographically contrasting sites, and dominated by calcareous and some robust agglutinated forms with calcitic cement (e.g. Eggerella).

  9. Benthic foraminifera baseline assemblages from a coastal nearshore reef complex on the central Great Barrier Reef (United States)

    Johnson, Jamie; Perry, Chris; Smithers, Scott; Morgan, Kyle


    Declining water quality due to river catchment modification since European settlement (c. 1850 A.D.) represents a major threat to the health of coral reefs on Australia's Great Barrier Reef (GBR), particularly for those located in the coastal waters of the GBR's inner-shelf. These nearshore reefs are widely perceived to be most susceptible to declining water quality owing to their close proximity to river point sources. Despite this, nearshore reefs have been relatively poorly studied with the impacts and magnitudes of environmental degradation still remaining unclear. This is largely due to ongoing debates concerning the significance of increased sediment yields against naturally high background sedimentary regimes. Benthic foraminifera are increasingly used as tools for monitoring environmental and ecological change on coral reefs. On the GBR, the majority of studies have focussed on the spatial distributions of contemporary benthic foraminiferal assemblages. While baseline assemblages from other environments (e.g. inshore reefs and mangroves) have been described, very few records exist for nearshore reefs. Here, we present preliminary results from the first palaeoecological study of foraminiferal assemblages of nearshore reefs on the central GBR. Cores were recovered from the nearshore reef complex at Paluma Shoals using percussion techniques. Recovery was 100%, capturing the entire Holocene reef sequence of the selected reef structures. Radiocarbon dating and subsequent age-depth modelling techniques were used to identify reef sequences pre-dating European settlement. Benthic foraminifera assemblages were reconstructed from the identified sequences to establish pre-European ecological baselines with the aim of providing a record of foraminiferal distribution during vertical reef accretion and against which contemporary ecological change may be assessed.

  10. Benthic Macroinvertebrates of Selected Aquatic Habitats of the Lower Mississippi River. (United States)


    1975) and provides a graphical summary of the similarity between samples, stations, or communities. This technique was introduced by Bray and Curtis ...drift. Miscellaneous Paper E-80-1, U. S. Army Engineer Waterways Experiment Station, CE, Vicksburg, Miss. Bray, J. R., and J. T. Curtis . 1957. An...J. Cairns, Jr., and J. M. Bates. 1971. Cluster analysis of non-insect macro-invertebrates of the upper Potomac River. Hydro- biologia 37:173-181

  11. Effects of sediment-spiked lufenuron on benthic macroinvertebrates in outdoor microcosms and single-species toxicity tests

    Energy Technology Data Exchange (ETDEWEB)

    Brock, T.C.M., E-mail: [Alterra, Wageningen University and Research Centre, P.O. Box 47, 6700 AA Wageningen (Netherlands); Bas, D.A. [Institute for Biodiversity and Ecosystem Dynamics (IBED), University of Amsterdam (Netherlands); Belgers, J.D.M. [Alterra, Wageningen University and Research Centre, P.O. Box 47, 6700 AA Wageningen (Netherlands); Bibbe, L. [Institute for Biodiversity and Ecosystem Dynamics (IBED), University of Amsterdam (Netherlands); Boerwinkel, M-C.; Crum, S.J.H. [Alterra, Wageningen University and Research Centre, P.O. Box 47, 6700 AA Wageningen (Netherlands); Diepens, N.J. [Department of Aquatic Ecology and Water Quality Management, Wageningen University, P.O. Box 47, 6700 AA Wageningen (Netherlands); Kraak, M.H.S.; Vonk, J.A. [Institute for Biodiversity and Ecosystem Dynamics (IBED), University of Amsterdam (Netherlands); Roessink, I. [Alterra, Wageningen University and Research Centre, P.O. Box 47, 6700 AA Wageningen (Netherlands)


    Highlights: • In outdoor microcosms constructed with lufenuron-spiked sediment we observed that this insecticide persistent in the sediment compartment. • Sediment exposure to lufenuron caused population-level declines (insects and crustaceans) and increases (mainly oligochaete worms) of benthic invertebrates. • The direct and indirect effects observed in the microcosms were supported by results of sediment-spiked single species tests with Chironomus riparius, Hyalella azteca and Lumbriculus variegatus. • The tier-1 effect assessment procedure for sediment organisms recommended by the European Food Safety Authority is protective for the treatment-related responses observed in the microcosm test. - Abstract: Sediment ecotoxicity studies were conducted with lufenuron to (i) complement the results of a water-spiked mesocosm experiment with this lipophilic benzoylurea insecticide, (ii) to explore the predictive value of laboratory single-species tests for population and community-level responses of benthic macroinvertebrates, and (iii) to calibrate the tier-1 effect assessment procedure for sediment organisms. For this purpose the concentration-response relationships for macroinvertebrates between sediment-spiked microcosms and those of 28-d sediment-spiked single-species toxicity tests with Chironomus riparius, Hyalella azteca and Lumbriculus variegatus were compared. Lufenuron persisted in the sediment of the microcosms. On average, 87.7% of the initial lufenuron concentration could still be detected in the sediment after 12 weeks. Overall, benthic insects and crustaceans showed treatment-related declines and oligochaetes treatment-related increases. The lowest population-level NOEC in the microcosms was 0.79 μg lufenuron/g organic carbon in dry sediment (μg a.s./g OC) for Tanytarsini, Chironomini and Dero sp. Multivariate analysis of the responses of benthic macroinvertebrates revealed a community-level NOEC of 0.79 μg a.s./g OC. The treatment

  12. Patterns of benthic assemblages invaded and non-invaded by Grateloupia turuturu across rocky intertidal habitats (United States)

    Freitas, Cristiano; Araújo, Rita; Bertocci, Iacopo


    Intertidal benthic assemblages invaded and non-invaded by the introduced Asian red alga Grateloupia turuturu were compared at a rocky shore along the NW coast of Portugal. The structure of whole assemblages, the total richness of taxa and the abundance of individual taxa were examined as response variables in two different habitats (rock pools and emergent rock), two shore levels (low and mid intertidal) and two dates of sampling (June 2013 and June 2014). Invaded and non-invaded assemblages differed consistently across habitats and shore levels. Such differences were driven by 13 (with the green alga genus Ulva, the red alga Chondrus crispus and the mussel Mytilus galloprovincialis driving the total dissimilarity) out of the total 37 taxa identified. Individual taxa revealed idiosyncratic patterns, in several cases (C. crispus, M. galloprovincialis, articulated coralline algae of the genus Corallina and the crustose sporophyte of the red alga Mastocarpus stellatus) there were differences in the abundance of a taxon between invaded and non-invaded assemblages varying with levels of some other experimental factors. The total number of taxa was higher in invaded compared to non-invaded assemblages for each combination of habitat and shore level. Patterns of invasion by G. turuturu along the Portuguese continental coast were recently described in terms of its temporal and spatial distribution, but never examined in terms of differences between invaded and non-invaded assemblages. Such information is very limited for other geographic areas where this species is recorded out of its native range of distribution. Therefore, the present study provides a new contribution to the understanding of modifications of native assemblages associated with the invasion of G. turuturu, opening avenues of research aimed at specifically examining the factors and processes likely responsible for the invasion dynamics and success of this species.

  13. Nitrogen dose-response relationships: benthic algae and macroinvertebrates in running water


    R Wright; Eriksen, T.; Schneider, S.


    Nitrogen deposition affects freshwater biodiversity in two ways: by contributing to acidification via nitrate in runoff, and by acting as a nutrient. We used data for two organism groups, benthic algae (224 sites) and benthic invertebrates (62 sites), to test if N as a nutrient affects the species numbers of these groups in running water. Neither of these groups showed significant relationships with nitrogen, except for a positive relationship between nitrate concentration and the number of b...

  14. Relationships between benthic macroinvertebrate community structure and geospatial habitat, in-stream water chemistry, and surfactants in the effluent-dominated Trinity River, Texas, USA. (United States)

    Slye, Jaime L; Kennedy, James H; Johnson, David R; Atkinson, Sam F; Dyer, Scott D; Ciarlo, Michael; Stanton, Kathleen; Sanderson, Hans; Nielsen, Allen M; Price, Bradford B


    Over the past 20 years, benthic macroinvertebrate community structure studies have been conducted on the upper Trinity River, Texas, USA, which is dominated by municipal wastewater treatment plant (WWTP) and industrial effluents. The Trinity River is located in the Dallas-Fort Worth metropolitan area, and is the most highly populated and industrialized watershed in Texas. As such, the Trinity River represents a near-worst-case scenario to examine the environmental effects of domestic-municipal and industrial effluents on aquatic life. A 1987 to 1988 study concluded that many stretches of the river supported a diverse benthic community structure; however, a decline in taxa richness occurred immediately downstream of WWTPs. A 2005 study designed to parallel the 1987 to 1988 efforts evaluated how changes in water quality, habitat, and increased urbanization impacted benthic community structure. Physicochemical measurements, habitat quality, geospatial variables, and benthic macroinvertebrates were collected from 10 sites. Surfactants were measured and toxic units (TUs) were calculated for surface water and pore water as indicators of domestic/household use of cleaning products. Total TUs indicated a low potential for biological impacts. Toxic unit distribution was not dependent on WWTP location and did not correlate with any benthic variable. Eight environmental parameters were determined to be useful for predicting changes in benthic macroinvertebrate community structure: surfactant surface water TUs (SWTU), in-stream habitat cover, and surface water total organic carbon were the top three parameters. Abundance, taxa richness, and taxa similarity in 2005 had increased since the earlier study throughout the immediate vicinity of the metropolitan area.

  15. Living and dead benthic foraminiferal assemblages from bathyal environment in the Pontine Archipelago (Tyrrhenian Sea, Italy) (United States)

    Di Bella, Letizia; Frezza, Virgilio; Ingrassia, Michela; Latino Chiocci, Francesco; Martorelli, Eleonora


    The western Pontine Archipelago (Tyrrhenian Sea, Italy), located about 30 km away from the Italian Peninsula, is composed of three volcanic islands (Ponza, Palmarola and Zannone). Sedimentological and micropaleontological characterization of the infralittoral and circalittoral zones in the Pontine Archipelago was already been studied, whereas it is lacking for deeper environments. The present study shows the preliminary micropaleontological results carried out on samples collected in the bathyal zone (at 500 mwd) in the Ventotene basin. Sediment samples, high resolution multibeam bathymetry, biological and video data were acquired in order to characterise both the morphological and biological features of study area, during the research cruise "BOLLE 2014" carried out on June 2014 aboard to the R/V Urania. Sediment samples were collected with a multi-corer, that allowed sampling of the upper decimetre of the sediments column. Successively, each core was sliced horizontally every 1 cm from the top to the bottom. For micropaleontological analyses, all samples were stained with Rose Bengal to distinguish living and dead assemblages. For each interval of the core all living specimens and 200 dead benthic foraminifera were classified and counted. Diversity index (α-Fisher, Shannon indices) and Faunal Density (specimens/gr) were calculated to define the structure of the assemblage. A variable number of living benthic foraminifera (Rose Bengal-stained) were found in all core-intervals (7-155 tests), with the Faunal Density ranging from 3 to 82 specimens/gr. A total of 77 species are recognised from living benthic foraminiferal assemblages, with a range of 4-31 species found in each core-interval. The α-Fisher index ranges between 3.88 and 43.45, whereas Shannon index shows a more limited variability (1.28-2.92). Among the living foraminifera, calcareous imperforate tests are very abundant, with percentages ranging between 33.3 and 100%; perforate species are subordinate


    A study was initiated in fall 2005 to assess potential effects on benthic fauna and habitat quality in coastal waters of Louisiana, Mississippi, and Alabama following Hurricane Katrina, which struck the coast of Louisiana, between New Orleans and Bioloxi, Mississippi on August 29...

  17. Role of Recruitment Processes in Structuring Coralligenous Benthic Assemblages in the Northern Adriatic Continental Shelf (United States)

    Abbiati, Marco


    Coralligenous biogenic reefs are among the most diverse marine habitats in the Mediterranean Sea. The northern Adriatic mesophotic coralligenous outcrops host very rich and diverse epibenthic assemblages. Several studies quantified the low temporal variability and high spatial heterogeneity of these habitats, while processes driving structuring and differentiation are still poorly understood. To shed light on these processes, temporal and spatial patterns of colonisation were investigated using travertine tiles deployed on three coralligenous outcrops, corresponding to the main typologies of benthic assemblages described in previous studies. Three years after deployment, assemblages colonising travertine tiles resembled the differentiation among sites revealed by the natural assemblages in terms of major ecological groups. Processes structuring and maintaining species diversity have been explored. Pioneer species with high reproduction rate, long distance larval dispersal and fast growth (e.g. the serpulid polychaete Spirobranchus triqueter and the bivalve Anomia ephippium), were the most abundant in the early stages of recruitment on the two outcrops further away from the coast and with lower sedimentation. Their success may vary according to larval availability and environmental conditions (e.g., sedimentation rates). At these sites early-stage lasted 10–12 months, during which even species from natural substrates began colonising tiles by settlement of planktonic propagules (e.g., encrusting calcareous Rhodophyta) and lateral encroachment (e.g., sponges and ascidians). On coastal outcrop, exposed to a higher sedimentation rates, tiles were colonised by fast-growing algal turfs. Resilience of northern Adriatic coralligenous assemblages, and maintenance of their diversity, appeared largely entrusted to asexual reproduction. Exploring the mechanisms that underlie the formation and maintenance of the species diversity is crucial to improve our understanding of

  18. Benthic macroinvertebrate community structure in relation to seasonal and geochemical changes in a chronically acidified stream

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    Madarish, D.M.; Kimmel, W.G. [California University of Pennsylvania, California, PA (USA). Dept. of Biology and Environmental Sciences


    The Blue Hole Creek basin (1652 ha) is located in an area of Pennsylvania that is historically high in wet deposition of sulfates and nitrates. Five stations on Cole Run (chronically acidified) and one on Blue-Hole Creek (episodically acidified) were sampled twice seasonally - once at base flow and once at high flow. Total iron, aluminium, and sulfate trended toward a direct relationship with discharge, while pH and alkalinity exhibited an inverse relationship. Stations with higher pH values were linked with the Mauch Chunk geologic formation and Fluvaquents soil series, while those with lower pH were linked with the Pottsville geologic formation and the Brinkerton, Cookport, and Rayne-Gilpin soil series. Fewer macroinvertebrates were collected from the episodically acidified station than at any of the chronically acidified stations on 71% of the sample dates. Although the number of taxa was similar between stations, more taxa were unique to Cole Run than to Blue Hole Creek. No clear patterns were discerned for season or flow.

  19. Water quality and benthic macroinvertebrate bioassessment of Gallinas Creek, San Miguel County, New Mexico, 1987-90 (United States)

    Garn, H.S.; Jacobi, G.Z.


    Upper Gallinas Creek in north-central New Mexico serves as the public water supply for the City of Las Vegas. The majority of this 84-square-mile watershed is within national forest lands managed by the U.S. Forest Service. In 1985, the Forest Service planned to conduct timber harvesting in the headwaters of Gallinas Creek. The City of Las Vegas was concerned about possible effects from logging on water quality and on water-supply treatment costs. The U.S. Geological Survey began a cooperative study in 1987 to (1) assess the baseline water-quality characteristics of Gallinas Creek upstream from the Las Vegas water-supply diversion, (2) relate water quality to State water- quality standards, and (3) determine possible causes for spatial differences in quality. During 1987-90, water-quality constituents and aquatic benthic macroinvertebrates were collected and analyzed at five sampling sites in the watershed. Specific conductance, pH, total hardness, total alkalinity, and calcium concentrations increased in a downstream direction, probably in response to differences in geology in the watershed. The water-quality standard for temperature was exceeded at the two most downstream sites probably due to a lack of riparian vegetation and low streamflow conditions. The standards for pH and turbidity were exceeded at all sites except the most upstream one. Concentrations of nitrogen species and phosphorus generally were small at all sites. The maximum total nitrogen concentration of 2.1 milligrams per liter was at the mouth of Porvenir Canyon; only one sample at this site exceeded the water-quality standard for total inorganic nitrogen. At each of the sites, 10 to 15 percent of the samples exceeded the total phosphorus standard of less than 0.1 milligram per liter. Except for aluminum and iron, almost all samples tested for trace elements contained concentrations less than the laboratory detection limit. No trace-element concentrations exceeded the State standard for domestic

  20. Effects of cutting disturbance in Schoenoplectus californicus (C.A. Mey. Soják on the benthic macroinvertebrates - doi: 10.4025/actascibiolsci.v33i1.6383 Effects of cutting disturbance in Schoenoplectus californicus (C.A. Mey. Soják on the benthic macroinvertebrates - doi: 10.4025/actascibiolsci.v33i1.6383

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    Norma Luiza Würdig


    Full Text Available Lagoons are considered protected areas because these systems play a key ecological role. However, the extraction of macrophyte Schoenoplectus californicus is held for manufacture of handcrafts, being an alternative income for riverbank communities. This study evaluated the impact of S. californicus experimental cutting on benthic macroinvertebrates trough a field experiment. Macroinvertebrates were sampled at 1, 12, 26 and 60 days after the macrophyte cutting in demarked plots (1 m², as well at control plots. The families number was not statistically different (ANOVA, p > 0.05, but the total density of invertebrates, and the density of Ceratopogonidae were significant (ANOVA, p S. californicus, in this area, as the intensity of the cut held, did not affect considerably the aquatic macroinvertebrates. The results suggest that the small-scale extractivism in these regions carries little effect because the fauna of adjacent areas probably can quickly colonize the disturbed areas.Lagoons are considered protected areas because these systems play a key ecological role. However, the extraction of macrophyte Schoenoplectus californicus is held for manufacture of handcrafts, being an alternative income for riverbank communities. This study evaluated the impact of S. californicus experimental cutting on benthic macroinvertebrates trough a field experiment. Macroinvertebrates were sampled at 1, 12, 26 and 60 days after the macrophyte cutting in demarked plots (1 m², as well at control plots. The families number was not statistically different (ANOVA, p > 0.05, but the total density of invertebrates, and the density of Ceratopogonidae were significant (ANOVA, p S. californicus, in this area, as the intensity of the cut held, did not affect considerably the aquatic macroinvertebrates. The results suggest that the small-scale extractivism in these regions carries little effect because the fauna of adjacent areas probably can quickly colonize the disturbed

  1. Bioassessment using benthic macroinvertebrates of the water quality in the Tigreiro river, Jacuí Basin - doi: 10.4025/actascibiolsci.v35i4.18934

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    Carlos Eduardo Copatti


    Full Text Available This study aimed to evaluate the water quality in the Tigreiro river, Jacuí river Basin, using different approaches. Benthic macroinvertebrates were sampled in July 2010 (winter and February 2011 (summer at five sites. In this study were analyzed: microbiological, physical and chemical variables, benthic macroinvertebrates richness and diversity, rapid ecological assessment protocol and benthic biotic indices (% EPT, BMWP’-IAP, ASPT, SOMI. A total of 5,852 individuals were collected belonging to 31 taxa of three Phyla: Annelida, Mollusca and Arthropoda. Chironomidae was the most abundant taxon (63.70%. A reduction in richness, diversity H’ and evenness J’ was observed from the initial stretches to the end stretches of Tigreiro river. The use of different approaches showed that sites in the rural area were less altered. The Tigreiro river was strongly impacted, mainly due to discharge of domestic effluents in the urban area, and the combination of different metrics was useful to detect impacted sites and the consequence for the water quality.

  2. Changes of planktonic and benthic foraminiferal assemblages in upper quaternary sediments of the Deryugin Basin, Sea of Okhotsk (United States)

    Khusid, T. A.; Belyaeva, N. V.; Demina, L. L.; Domanov, M. M.; Chekhovskaya, M. P.


    The analysis of foraminiferal assemblages in sediments that were deposited during the last 30 kyr revealed similar patterns in their distribution in the central and marginal parts of the Deryugin Basin. The similar composition of foraminifers through the entire basin implies similarity in natural environments within its limits. The absence of benthic foraminifers or extreme impoverishment of the assemblages during the maximum of the last glaciation could result from a combination of several factors: drastic decrease in bioproductivity due to general cooling, development of bottom anoxia, and presumably unfavorable influence of seeps on geochemical parameters of bottom waters. The weak activity of barite-methane seeps in the central part of the basin during the Holocene is evident from some variations in the structure of benthic foraminiferal assemblages against the background of their similar taxonomic compositions.

  3. A survey of benthic assemblages of foraminifera in tropical coastal waters of pulau pinang, malaysia. (United States)

    Minhat, Fatin Izzati; Yahya, Khairun; Talib, Anita; Ahmad, Omar


    The distribution of benthic Foraminifera throughout the coastal waters of Taman Negara Pulau Pinang (Penang National Park), Malaysia was studied to assess the impact of various anthropogenic activities, such as fishing, ecotourism and floating cage culture. Samples were obtained at 200 m intervals within the subtidal zone, extending up to 1200 m offshore at Teluk Bahang, Teluk Aling, Teluk Ketapang and Pantai Acheh. The depth within coastal waters ranged between 1.5 m and 10.0 m, with predominantly muddy substrate at most stations. Water quality analysis showed little variation in micronutrient (nitrite, NO2; nitrate, NO3; ammonia, NH4 and orthophosphate, PO4) concentrations between sampling stations. Temperature (29.6±0.48°C), salinity (29.4±0.28 ppt), dissolved oxygen content (5.4±0.95 mg/l) and pH (8.5± 0.13) also showed little fluctuation between stations. A total of nine genera of foraminifera were identified in the study (i.e., Ammonia, Elphidium, Ammobaculites, Bigenerina, Quinqueloculina, Reopax, Globigerina, Textularia and Nonion). The distribution of benthic foraminifera was dominated by opportunistic groups that have a high tolerance to anthropogenic stressors. Ammonia had the highest frequency of occurrence (84.7%), followed by Bigenerina (50%), Ammobaculites (44.2%) and Elphidium (38.9%). The Ammonia-Elphidium Index (AEI) was used to describe the hypoxic condition of benthic communities at all sites. Teluk Bahang had the highest AEI value. The foraminiferal assemblages and distribution in Teluk Bahang, Teluk Aling, Teluk Ketapang and Pantai Acheh showed no correlation with physical or chemical environmental parameters.

  4. The Influence of Methane Venting on Benthic Foraminiferal Assemblages in Guaymas Basin, Gulf of California (United States)

    Perez, E.; Herguera, J.; Paull, C.; Ussler, W.; Cortina, A.


    Fossil foraminifera are critical for paleoenvironmental reconstructions including the study of past episodes of methane venting from gas hydrate reservoirs. However, the use of benthic foraminifera as indicators of methane release remains controversial and more modern analog data is needed to understand the ecology and isotopic signatures of foraminifera in methane seeps. The objective of this investigation was to characterize the species composition and vertical distribution of living benthic foraminifera (rose Bengal stained) along known gradients of present methane venting in order to gain insight into the ecological tolerances and preferences of benthic foraminifera in methane seeps. Vertical distribution patterns are also important in determining carbon isotope variability. Samples were retrieved along the NE transform margin of the Guaymas Basin in the Gulf of California (about 1,582 m). Suites of ROV cores were collected from beds of living calyptogenid clams, tubeworms, and bacterial mats; from a methane venting site evidenced by a continuous stream of gas bubbles; and from control sites. Our data shows that foraminiferal abundance is lower in the methane-influenced sites than in the control sites. Lowest foraminiferal abundance occurs at the bacterial mats, probably caused by higher levels of sulfide. The assemblage is dominated by calcareous species that are characteristic of other organic-rich, oxygen-poor environments (e.g., Uvigerina peregrina, Bulimina mexicana, Buliminella tenuata, Globobulimina pacifica). The vertical distributions of several species are different from those of conspecifics observed in previous studies of non-seep habitats, with deeper and broader depth ranges for some species at the methane-influenced habitats in this study. Of special interest is the occurrence of Planulina wuellerstorfi, traditionally considered an epifaunal species, at sediment depths of 6 cm and with density maxima between 1 and 3 cm. This may result from

  5. Relations Between the Structure of Benthic Macro-Invertebrates and the Composition of Adult Water Beetle Diets from the Dytiscidae Family. (United States)

    Frelik, Anna; Pakulnicka, Joanna


    This paper investigates the relations between the diet structure of predaceous adult water beetles from the Dytiscidae family and the structure of macrofauna inhabiting the same environments. The field studies were carried out from April until September in 2012 and 2013 in 1-mo intervals. In total, >1,000 water beetles and 5,115 benthic macro-invertebrates were collected during the whole period of the study. Subsequently, 784 specimens of adult water beetles (70.6% out of the total sampled) with benthic macro-invertebrates found in their proventriculi, were subject to analysis. The predators were divided into three categories depending on their body size: small beetles (2.3-5.0 mm), medium-sized beetles (13-15 mm), and large beetles (27-37 mm). All adult Dytiscidae consumed primarily Ephemeroptera and Chironomidae larvae. Although Asellidae were numerically dominant inhabitants of the sites, the adult water beetles did not feed on them. The analysis of feeding relations between predators and their prey revealed that abundance of Ephemeroptera, Chironomidae, and larval Dytiscidae between the environment and the diet of adult Dytiscidae were strongly correlated.

  6. Dynamics of coral reef benthic assemblages of the Abrolhos Bank, eastern Brazil: inferences on natural and anthropogenic drivers.

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    Ronaldo B Francini-Filho

    Full Text Available The Abrolhos Bank (eastern Brazil encompasses the largest and richest coral reefs of the South Atlantic. Coral reef benthic assemblages of the region were monitored from 2003 to 2008. Two habitats (pinnacles' tops and walls were sampled per site with 3-10 sites sampled within different reef areas. Different methodologies were applied in two distinct sampling periods: 2003-2005 and 2006-2008. Spatial coverage and taxonomic resolution were lower in the former than in the latter period. Benthic assemblages differed markedly in the smallest spatial scale, with greater differences recorded between habitats. Management regimes and biomass of fish functional groups (roving and territorial herbivores had minor influences on benthic assemblages. These results suggest that local environmental factors such as light, depth and substrate inclination exert a stronger influence on the structure of benthic assemblages than protection from fishing. Reef walls of unprotected coastal reefs showed highest coral cover values, with a major contribution of Montastraea cavernosa (a sediment resistant species that may benefit from low light levels. An overall negative relationship between fleshy macroalgae and slow-growing reef-building organisms (i.e. scleractinians and crustose calcareous algae was recorded, suggesting competition between these organisms. The opposite trend (i.e. positive relationships was recorded for turf algae and the two reef-building organisms, suggesting beneficial interactions and/or co-occurrence mediated by unexplored factors. Turf algae cover increased across the region between 2006 and 2008, while scleractinian cover showed no change. The need of a continued and standardized monitoring program, aimed at understanding drivers of change in community patterns, as well as to subsidize sound adaptive conservation and management measures, is highlighted.

  7. Dynamics of coral reef benthic assemblages of the Abrolhos Bank, eastern Brazil: inferences on natural and anthropogenic drivers. (United States)

    Francini-Filho, Ronaldo B; Coni, Ericka O C; Meirelles, Pedro M; Amado-Filho, Gilberto M; Thompson, Fabiano L; Pereira-Filho, Guilherme H; Bastos, Alex C; Abrantes, Douglas P; Ferreira, Camilo M; Gibran, Fernando Z; Güth, Arthur Z; Sumida, Paulo Y G; Oliveira, Nara L; Kaufman, Les; Minte-Vera, Carolina V; Moura, Rodrigo L


    The Abrolhos Bank (eastern Brazil) encompasses the largest and richest coral reefs of the South Atlantic. Coral reef benthic assemblages of the region were monitored from 2003 to 2008. Two habitats (pinnacles' tops and walls) were sampled per site with 3-10 sites sampled within different reef areas. Different methodologies were applied in two distinct sampling periods: 2003-2005 and 2006-2008. Spatial coverage and taxonomic resolution were lower in the former than in the latter period. Benthic assemblages differed markedly in the smallest spatial scale, with greater differences recorded between habitats. Management regimes and biomass of fish functional groups (roving and territorial herbivores) had minor influences on benthic assemblages. These results suggest that local environmental factors such as light, depth and substrate inclination exert a stronger influence on the structure of benthic assemblages than protection from fishing. Reef walls of unprotected coastal reefs showed highest coral cover values, with a major contribution of Montastraea cavernosa (a sediment resistant species that may benefit from low light levels). An overall negative relationship between fleshy macroalgae and slow-growing reef-building organisms (i.e. scleractinians and crustose calcareous algae) was recorded, suggesting competition between these organisms. The opposite trend (i.e. positive relationships) was recorded for turf algae and the two reef-building organisms, suggesting beneficial interactions and/or co-occurrence mediated by unexplored factors. Turf algae cover increased across the region between 2006 and 2008, while scleractinian cover showed no change. The need of a continued and standardized monitoring program, aimed at understanding drivers of change in community patterns, as well as to subsidize sound adaptive conservation and management measures, is highlighted.

  8. Assessment of the effects of the dry period on the faunal composition of aquatic macroinvertebrate assemblages in two temporary ponds in NW Spain

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    Amaia Pérez-Bilbao


    Full Text Available Temporary ponds are habitats that undergo periods of drying and flooding. They have been neglected for many years and changes produced by climatic change will greatly affect them. Thus, nowadays they constitute an endangered ecosystem due to their characteristics and to human pressures. These habitats support a high biological richness with species adapted to extreme conditions. Assuming that hydroperiod is the main factor structuring aquatic assemblages in this type of ecosystem, the aim of this study was to assess the effect of the dry period on the faunal composition and the natural succession process of macroinvertebrate assemblages in two temporary ponds and to analyze the differences between two periods, before and after the dry period. A total of 7225 individuals belonging to 93 macroinvertebrate taxa (Nematoda, Hirudinea, Oligochaeta, Mollusca, Crustacea, Acari, Insecta were collected. The most abundant and richest group were insects. Cluster and Non-Metric Multi-Dimensional Scaling (NMDS analyses showed the clustering of the samples in two groups, before and after the dry period, as we had expected. Thus, there was a change in faunal composition in both ponds, corresponding to a successional process. According to the SIMPER analysis, the most contributive taxa in both ponds were mostly insects and crustaceans. Regarding feeding traits, predators and shredders were the dominant groups. However, there was a change in the trophic structure of the assemblages between the two periods. Most taxa resist the drying season with resting eggs, cocoons or simply by flying to more permanent freshwater bodies. Although the two studied ponds are temporary habitats, they support a different faunal composition hosting species that are endemic or rare at regional or national level. 

  9. 城镇化对西苕溪大型底栖动物群落的影响%Influence of Urbanization on Benthic Macroinvertebrate in Xitiaoxi Watershed

    Institute of Scientific and Technical Information of China (English)

    俞建; 于海燕; 丁宁; 韩鸣花


    Urbanization is of great impact on stream ecosystem health .We sampled 20 reference sites , 5 moderately disturbed sites and 2 heavily disturbed sites in May from 2004 and 2010 in Xitiaoxi watershed .We identified a total of 226 species which belonged to 190 genera and 74 families.We found significant decrease in taxa richness of benthic macroinvertebrate , EPT taxa richness , Shannon-Wiener diversity index and B-IBI index in disturbed sites , and a significant increase of BI index .Canonical Correspon-dence Analysis ( CCA) well separated the benthic macroinvertebrate communities of the reference , moderately and heavily disturbed sites.The urbanization related factors , such as water temperature increase , nutrients enrichment , high load of fine sediments and bank stabilization greatly contributed to the decline of benthic macroinvertebrae diversity .%于2004—2010年5月对西苕溪流域20个参照点,5个中度干扰点以及2个重度干扰点的底栖动物进行了调查,共鉴定出74科190属226个种;受干扰后,底栖动物群落物种丰富度、EPT物种丰富度、Shannon-wiener多样性指数和B-IBI指数显著下降,BI指数显著升高。 CCA分析结果表明,参照、中度和重点干扰样点的底栖动物群落差异明显。城镇化引起的溪流水温上升、营养盐升高、泥沙输入量增多和堤岸固化是导致溪流底栖动物群落退化的主要原因。

  10. Reef fish and benthic assemblages of the Trindade and Martin Vaz Island group, southwestern Atlantic

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    Guilherme Henrique Pereira-Filho


    Full Text Available The Trindade and Martin Vaz island group (TMVIG is located at about 1,120 km off the Brazilian coast. Despite its importance, highlighted by the presence of several endemic fish species, the TMVIG lacks detailed information on the structure of fish and benthic assemblages. Presented here is the first quantitative assessment of reef fish and benthic assemblages of the TMVIG in a depth gradient ranging from 5 to 45 m. Additional qualitative information on reef assemblages between 45 and 100 m was obtained using advanced gas diving techniques (TRIMIX and a remotely operated vehicle (ROV. Similarly to other Brazilian oceanic islands, the TMVIG possesses depauperated fish and benthic assemblages, possibly due to its isolation and small size in comparison to the mainland. Depth was the most important factor affecting the structure of fish assemblages, with the density of most fish species declining with depth. Deep reefs (> 45 m were characterized by the presence of extensive rhodolith beds and rocky reefs sparsely covered with crustose coralline algae, black coral (Cirripathes sp. and a few massive or plate-like reef corals. Part-time or obligatory planktivorous fishes (e.g. Cephalopholis furcifer and Clepticus brasiliensis also dominated deep reefs. Similar characteristics were recorded in mesophotic reef ecosystems across the Western Atlantic. Evidence of overfishing (obtained here and in other recent studies, the presence of four endemic and restricted range fish species, as well as the increase in number of new (and still undescribed endemic taxa, indicates that the adoption of precautionary conservation measures are urgently needed in order to maintain the fragile and unique ecosystems of the TMVIG.O conjunto insular de Trindade e Martin Vaz (CITMV está localizado a aproximadamente 1.120 km da costa brasileira. Apesar de sua importância, salientada pela presença de diversas espécies endêmicas de peixes, não existem informações detalhadas

  11. Assessing condition of macroinvertebrate communities and sediment toxicity in the St. Lawrence River at Massena Area-of-Concern (United States)

    Duffy, Brian T.; Baldigo, Barry P.; Smith, Alexander J; George, Scott D.; David, Anthony M.


    In 1972, the USA and Canada agreed to restore the chemical, physical, and biological integrity of the Great Lakes ecosystem under the first Great Lakes Water Quality Agreement. In subsequent amendments, part of the St. Lawrence River at Massena, New York and segments of three tributaries, were designated as an Area of Concern (AOC) due to the effects of polychlorinated biphenyls (PCBs), lead and copper contamination, and habitat degradation and resulting impairment to several beneficial uses. Because sediments have been largely remediated, the present study was initiated to evaluate the current status of the benthic macroinvertebrate (benthos) beneficial use impairment (BUI). Benthic macroinvertebrate communities and sediment toxicity tests using Chironomus dilutus were used to test the hypotheses that community condition and sediment toxicity at AOC sites were not significantly different from those of adjacent reference sites. Grain size was found to be the main driver of community composition and macroinvertebrate assemblages, and bioassessment metrics did not differ significantly between AOC and reference sites of the same sediment class. Median growth of C. dilutus and its survival in three of the four river systems did not differ significantly in sediments from AOC and reference sites. Comparable macroinvertebrate assemblages and general lack of toxicity across most AOC and reference sites suggest that the quality of sediments should not significantly impair benthic macroinvertebrate communities in most sites in the St. Lawrence River AOC.

  12. Comparison of watershed disturbance predictive models for stream benthic macroinvertebrates for three distinct ecoregions in western US (United States)

    Waite, I.R.; Brown, L.R.; Kennen, J.G.; May, J.T.; Cuffney, T.F.; Orlando, J.L.; Jones, K.A.


    The successful use of macroinvertebrates as indicators of stream condition in bioassessments has led to heightened interest throughout the scientific community in the prediction of stream condition. For example, predictive models are increasingly being developed that use measures of watershed disturbance, including urban and agricultural land-use, as explanatory variables to predict various metrics of biological condition such as richness, tolerance, percent predators, index of biotic integrity, functional species traits, or even ordination axes scores. Our primary intent was to determine if effective models could be developed using watershed characteristics of disturbance to predict macroinvertebrate metrics among disparate and widely separated ecoregions. We aggregated macroinvertebrate data from universities and state and federal agencies in order to assemble stream data sets of high enough density appropriate for modeling in three distinct ecoregions in Oregon and California. Extensive review and quality assurance of macroinvertebrate sampling protocols, laboratory subsample counts and taxonomic resolution was completed to assure data comparability. We used widely available digital coverages of land-use and land-cover data summarized at the watershed and riparian scale as explanatory variables to predict macroinvertebrate metrics commonly used by state resource managers to assess stream condition. The "best" multiple linear regression models from each region required only two or three explanatory variables to model macroinvertebrate metrics and explained 41-74% of the variation. In each region the best model contained some measure of urban and/or agricultural land-use, yet often the model was improved by including a natural explanatory variable such as mean annual precipitation or mean watershed slope. Two macroinvertebrate metrics were common among all three regions, the metric that summarizes the richness of tolerant macroinvertebrates (RICHTOL) and some form

  13. The impact of a catastrophic storm event on benthic macroinvertebrate communities in upland headwater streams and potential implications for ecological diversity and assessment of ecological status

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    Mary Kelly-Quinn


    Full Text Available Upland headwater streams are dynamic systems, responding rapidly to changes in climatic conditions. This study examined the effects of a catastrophic rainfall event, that occured on 24 October 2011 on the east coast of Ireland, on the macroinvertebrate community composition and structure of four headwater streams in the river Liffey catchment located in the Wicklow Mountains. The ecological status before and after the storm were also evaluated. The water level and pH of each stream were recorded using continuous monitoring equipment, while rainfall data for the study period were sourced from a local weather station. Benthic macroinvertebrates were investigated before and after the storm event using Surber sampling. Results showed rapid and large increases in water level and significant declines in stream pH in response to intensive rainfall during the storm. The high water levels also caused major physical damage and abrasion in all four streams, that significantly altered instream habitats. The storm event induced significant losses to the richness and/or density of most taxonomic groups, with the exception of the Plecoptera. Furthermore, the overall community composition and structure changed significantly, most likely as a result of physical disturbance, given the relative persistence of acid-sensitive taxa and the relatively short period of harsh acidic conditions (<5 pH. Interestingly however, the ecological status of each of the four study sites, tested using Stream Risk Score (SSRS, Biological Monitoring Working Party (BMWP and the Average Score Per Taxon (ASPT indices, was unaltered by the loss in richness and densities. This was likely a result of the maintenance of plecopteran richness and the absence of organic pollution, thus highlighting the need to develop appropriate indices to assess the ecological status of streams and rivers affected by physical disturbance caused by large storm events. Ultimately, catastrophic storm events in

  14. The impact of an industrial effluent on the water quality, submersed macrophytes and benthic macroinvertebrates in a dammed river of Central Spain. (United States)

    Gonzalo, Cristina; Camargo, Julio A


    This research was conducted in the middle Duratón River (Central Spain), in the vicinity of Burgomillodo Reservoir. An industrial effluent enters the river 300 m downstream from the dam. Fluoride and turbidity levels significantly increased downstream from the effluent, these levels being to some extent affected by differential water releases from the dam. The community of submersed macrophytes exhibited slighter responses and, accordingly, lower discriminatory power than the community of benthic macroinvertebrates, this indicating that metrics and indices based on macroinvertebrates may be more suitable for the biological monitoring of water pollution and habitat degradation in dammed rivers receiving industrial effluents. However, in relation to fluoride bioaccumulation at the organism level, macrophytes (Fontinalis antipyretica and Potamogeton pectinatus) were as suitable bioindicators of fluoride pollution as macroinvertebrates (Ancylus fluviatilis and Pacifastacus leniusculus). Fluoride bioaccumulation in both hard and soft tissues of these aquatic organisms could be used as suitable bioindicator of fluoride pollution (even lower than 1 mg F(-)L(-1)) in freshwater ecosystems. Echinogammarus calvus exhibited a great sensitivity to the toxicity of fluoride ions, with a 96 h LC₅₀ of 7.5 mg F(-)L(-1) and an estimated safe concentration of 0.56 mg F(-)L(-1). The great capacity of E. calvus to take up and retain fluoride during exposures to fluoride ions would be a major cause of its great sensitivity to fluoride toxicity. It is concluded that the observed fluoride pollution might be partly responsible for the absence of this native amphipod downstream from the industrial effluent.

  15. Effectiveness of benthic foraminiferal and coral assemblages as water quality indicators on inshore reefs of the Great Barrier Reef, Australia (United States)

    Uthicke, S.; Thompson, A.; Schaffelke, B.


    Although the debate about coral reef decline focuses on global disturbances (e.g., increasing temperatures and acidification), local stressors (nutrient runoff and overfishing) continue to affect reef health and resilience. The effectiveness of foraminiferal and hard-coral assemblages as indicators of changes in water quality was assessed on 27 inshore reefs along the Great Barrier Reef. Environmental variables (i.e., several water quality and sediment parameters) and the composition of both benthic foraminiferal and hard-coral assemblages differed significantly between four regions (Whitsunday, Burdekin, Fitzroy, and the Wet Tropics). Grain size and organic carbon and nitrogen content of sediments, and a composite water column parameter (based on turbidity and concentrations of particulate matter) explained a significant amount of variation in the data (tested by redundancy analyses) in both assemblages. Heterotrophic species of foraminifera were dominant in sediments with high organic content and in localities with low light availability, whereas symbiont-bearing mixotrophic species were dominant elsewhere. A similar suite of parameters explained 89% of the variation in the FORAM index (a Caribbean coral reef health indicator) and 61% in foraminiferal species richness. Coral richness was not related to environmental setting. Coral assemblages varied in response to environmental variables, but were strongly shaped by acute disturbances (e.g., cyclones, Acanthaster planci outbreaks, and bleaching), thus different coral assemblages may be found at sites with the same environmental conditions. Disturbances also affect foraminiferal assemblages, but they appeared to recover more rapidly than corals. Foraminiferal assemblages are effective bioindicators of turbidity/light regimes and organic enrichment of sediments on coral reefs.

  16. After site selection and before data analysis: sampling, sorting, and laboratory procedures used in stream benthic macroinvertebrate monitoring programs by USA state agencies (United States)

    Carter, James L.; Resh, Vincent H.


    A survey of methods used by US state agencies for collecting and processing benthic macroinvertebrate samples from streams was conducted by questionnaire; 90 responses were received and used to describe trends in methods. The responses represented an estimated 13,000-15,000 samples collected and processed per year. Kicknet devices were used in 64.5% of the methods; other sampling devices included fixed-area samplers (Surber and Hess), artificial substrates (Hester-Dendy and rock baskets), grabs, and dipnets. Regional differences existed, e.g., the 1-m kicknet was used more often in the eastern US than in the western US. Mesh sizes varied among programs but 80.2% of the methods used a mesh size between 500 and 600 (mu or u)m. Mesh size variations within US Environmental Protection Agency regions were large, with size differences ranging from 100 to 700 (mu or u)m. Most samples collected were composites; the mean area sampled was 1.7 m2. Samples rarely were collected using a random method (4.7%); most samples (70.6%) were collected using "expert opinion", which may make data obtained operator-specific. Only 26.3% of the methods sorted all the organisms from a sample; the remainder subsampled in the laboratory. The most common method of subsampling was to remove 100 organisms (range = 100-550). The magnification used for sorting ranged from 1 (sorting by eye) to 30x, which results in inconsistent separation of macroinvertebrates from detritus. In addition to subsampling, 53% of the methods sorted large/rare organisms from a sample. The taxonomic level used for identifying organisms varied among taxa; Ephemeroptera, Plecoptera, and Trichoptera were generally identified to a finer taxonomic resolution (genus and species) than other taxa. Because there currently exists a large range of field and laboratory methods used by state programs, calibration among all programs to increase data comparability would be exceptionally challenging. However, because many techniques are

  17. Using Benthic Macroinvertebrate and Fish Communities as Bioindicators of the Tanshui River Basin Around the Greater Taipei Area — Multivariate Analysis of Spatial Variation Related to Levels of Water Pollution

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    Shuh-Sen Young


    Full Text Available After decades of strict pollution control and municipal sewage treatment, the water quality of the Tanshui River increased significantly after pollution mitigation as indicated by the River Pollution Index (RPI. The pollution level of the estuarine region decreased from severe pollution to mostly moderately impaired. The most polluted waters are presently restricted to a flow track length between 15–35 km relative to the river mouth. From July 2011 to September 2012, four surveys of fish and benthic macroinvertebrates were conducted at 45 sampling sites around the Tanshui River basin. The pollution level of all the study area indicated by the RPI could also be explained by the Family Biotic Index (FBI and Biotic Index (BI from the benthic macroinvertebrate community, and the Index of Biotic Integrity (IBI of the fish community. The result of canonical correlation analysis between aquatic environmental factors and community structure indicated that the community structure was closely related to the level of water pollution. Fish species richness in the estuarine area has increased significantly in recent years. Some catadromous fish and crustaceans could cross the moderate polluted water into the upstream freshwater, and have re-colonized their populations. The benthic macroinvertebrate community relying on the benthic substrate of the estuarine region is still very poor, and the water layer was still moderately polluted.

  18. Assessing streamflow characteristics as limiting factors on benthic invertebrate assemblages in streams across the western United States (United States)

    Konrad, C.P.; Brasher, A.M.D.; May, J.T.


    1. Human use of land and water resources modifies many streamflow characteristics, which can have significant ecological consequences. Streamflow and invertebrate data collected at 111 sites in the western U.S.A. were analysed to identify streamflow characteristics (magnitude, frequency, duration, timing and variation) that are probably to limit characteristics of benthic invertebrate assemblages (abundance, richness, diversity and evenness, functional feeding groups and individual taxa) and, thus, would be important for freshwater conservation and restoration. Our analysis investigated multiple metrics for each biological and hydrological characteristic, but focuses on 14 invertebrate metrics and 13 streamflow metrics representing the key associations between streamflow and invertebrates.

  19. Stable-isotope analysis of a deep-sea benthic-fish assemblage: evidence of an enriched benthic food web. (United States)

    Boyle, M D; Ebert, D A; Cailliet, G M


    In this study, fishes and invertebrates collected from the continental slope (1000 m) of the eastern North Pacific Ocean were analysed using stable-isotope analysis (SIA). Resulting trophic positions (T(P) ) were compared to known diets and habitats from the literature. Dual isotope plots indicated that most species groups (invertebrates and fishes) sorted as expected along the carbon and nitrogen axes, with less intraspecific variability than interspecific variability. Results also indicated an isotopically distinct benthic and pelagic food web, as the benthic food web was more enriched in both nitrogen and carbon isotopes. Trophic positions from SIA supported this finding, resulting in the assignment of fishes to different trophic positions from those expected based on published dietary information. These differences can be explained largely by the habitat of the prey and the percentage of the diet that was scavenged. A mixing model estimated dietary contributions of prey similar to those of the known diet of Bathyraja trachura from stomach-content analysis (SCA). Linear regressions indicated that trophic positions calculated from SIA and SCA, when plotted against B. trachura total length for 32 individuals, exhibited similar variation and patterns. Only the T(P) from SCA yielded significant results (stomach content: P 0·05).

  20. Impacts of acidification on macroinvertebrate communities in streams of the western Adirondack Mountains, New York, USA (United States)

    Baldigo, Barry P.; Lawrence, G.B.; Bode, R.W.; Simonin, H.A.; Roy, K.M.; Smith, A.J.


    Limited stream chemistry and macroinvertebrate data indicate that acidic deposition has adversely affected benthic macroinvertebrate assemblages in numerous headwater streams of the western Adirondack Mountains of New York. No studies, however, have quantified the effects that acidic deposition and acidification may have had on resident fish and macroinvertebrate communities in streams of the region. As part of the Western Adirondack Stream Survey, water chemistry from 200 streams was sampled five times and macroinvertebrate communities were surveyed once from a subset of 36 streams in the Oswegatchie and Black River Basins during 2003-2005 and evaluated to: (a) document the effects that chronic and episodic acidification have on macroinvertebrate communities across the region, (b) define the relations between acidification and the health of affected species assemblages, and (c) assess indicators and thresholds of biological effects. Concentrations of inorganic Al in 66% of the 200 streams periodically reached concentrations toxic to acid-tolerant biota. A new acid biological assessment profile (acidBAP) index for macroinvertebrates, derived from percent mayfly richness and percent acid-tolerant taxa, was strongly correlated (R2 values range from 0.58 to 0.76) with concentrations of inorganic Al, pH, ANC, and base cation surplus (BCS). The BCS and acidBAP index helped remove confounding influences of natural organic acidity and to redefine acidification-effect thresholds and biological-impact categories. AcidBAP scores indicated that macroinvertebrate communities were moderately or severely impacted by acidification in 44-56% of 36 study streams, however, additional data from randomly selected streams is needed to accurately estimate the true percentage of streams in which macroinvertebrate communities are adversely affected in this, or other, regions. As biologically relevant measures of impacts caused by acidification, both BCS and acidBAP may be useful

  1. Are the effects of an invasive crayfish on lake littoral macroinvertebrate communities consistent over time?

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    Ruokonen T. J.


    Full Text Available Management of invasive species requires assessment of their effects on recipient ecosystems. However, impact assessment of invasive species commonly lacks a long-term perspective which can potentially lead to false conclusions. We examined the effects of the invasive signal crayfish (Pacifastacus leniusculus Dana on the stony littoral macroinvertebrate communities of a large boreal lake and assessed the extent to which the patterns observed in previous short-term studies were stable over time. We used temporal macroinvertebrate data collected in five consecutive years from a site with a well-established crayfish population, a site with no crayfish and a site where crayfish had been recently introduced. Our results revealed that signal crayfish had temporally rather consistent negative effects on the benthic macroinvertebrate assemblages but that the effects might be limited to certain taxa, in particular Gastropoda and Coleoptera. We also observed increases in Gastropoda density and taxa richness following a decline in crayfish density, indicating that the recovery of invertebrate assemblages might be fast. Hence, negative effects on benthic macroinvertebrates can likely be minimized by effective control of the signal crayfish population.

  2. The Expansion of Dreissena and Long-term Shifts in Benthic Macroinvertebrate Community Structure in Lake Ontario, 1998-2008 (United States)

    The introduction of Dreissena to the Great lakes has profoundly impacted benthic ecosystems, resulting in the decline of native species and dramatic community restructuring. In Lake Ontario, long-term monitoring has yielded a wealth of detailed information regarding both the exp...

  3. The influence of finfish aquaculture on benthic fish and crustacean assemblages in Fitzgerald Bay, South Australia. (United States)

    Tanner, Jason E; Williams, Kane


    The influence of sea-cage aquaculture on wildfish assemblages has received little attention outside of Europe. Sea-cage aquaculture of finfish is a major focus in South Australia, and while the main species farmed is southern bluefin tuna (Thunnus maccoyii), there is also an important yellowtail kingfish (Seriola lalandi) industry. Yellowtail kingfish aquaculture did not appear to have any local or regional effects on demersal assemblages (primarily fish, but also some crustaceans) surveyed by baited remote underwater video (BRUV) in Fitzgerald Bay. We did, however, detect small scale spatial variations in assemblages within the bay. The type of bait used strongly influenced the assemblage recorded, with significantly greater numbers of fish attracted to deployments where sardines were used as the bait to compared to those with no bait. The pelleted feed used by the aquaculture industry was just as attractive as sardines at one site, and intermediate between sardines and no bait at the other. There was significant temporal variability in assemblages at both farm sites and one control site, while the second control site was temporally stable (over the 9 weeks of the study). Overall, the results suggested that aquaculture was having little if any impact on the abundance and assemblage structure of the demersal macrofauna in Fitzgerald Bay.

  4. Benthic faunal assemblages from the Holocene middle shelf of the South Evoikos Gulf, central Greece, and their palaeoenvironmental implications (United States)

    Asimina Louvari, Markella; Tsourou, Theodora; Drinia, Hara; Anastasakis, George


    South Evoikos Gulf is an elongate, WNW - ESE trending basin, 60 km long and 15 km wide. Its floor slopes towards the south-east where the basin connects with the Aegean Sea across a 55 m deep sill. The hydrographic network of the area is characterized by Asopos river the small Lilas River and some other ephemeral streams. A sedimentary record spanning the last 13000 calyr BP was recovered at N 38°12'23.1228" E 24°8'14.2404", water depth 70 m, in this gulf. A total of 52 samples from the lower half of the core were quantitatively analyzed for micropalaeontological (benthic foraminifera and ostracods) study in order to reconstruct palaeoenvironmental conditions. This work contributes to the evaluation of the modern environmental problems in South Evoikos Gulf (hypoxia, ecosystem changes, subaquatic vegetation die-off, metal pollution) within the context of the palaeoenvironmental record. In the investigated core, the benthic microfaunal assemblages indicate a marine coastal environment with a gradual transition from a circalittoral to an infralittoral restricted environment. The basal part of the record is characterized by Haynesina depressula Assemblage, which is composed of Haynesina depressula, Textularia agglutinans and Bulimina aculeata.The abundance of Haynesina depressula could be associated with normal marine conditions, but always with periodic brackish water influence. The species composed this assemblage, which are almost all typically infaunal, characterize sediments with a high or medium-high muddy fraction, rich in organic matter available for the organisms that live within the sediment, and low salinity bottom water. Samples from the upper unit of the core indicate a nearshore, inner-shelf facies less than 50 m deep. Common inner-shelf species in these samples include Ammonia beccarii together with Bulimina marginata (Sgarrella & Moncharmont Zei, 1993). The highest abundance of A. beccarii is found between 15 and 20 m water-depth in samples with

  5. The distribution of benthic foraminiferal assemblages in the north-west coastal region of Malacca Straits, Malaysia

    Institute of Scientific and Technical Information of China (English)

    Khairun Yahya; Shuhaida Shuib; Fatin Izzati Minhat; Omar Ahmad; Anita Talib


    Objective: To investigate the spatial and temporal distribution of benthic foraminiferal assemblages in relation with environmental parameters in Penang Island (the northern part of Malacca Straits, west coast of Peninsula Malaysia). Methods: Foraminifera samples were obtained from 144 sediment samples collected bimonthly throughout a one year sampling period using Ponar grab. These samples were then fixed with 4%buffered formalin stained with Rose Bengal. Temperature, salinity, dissolved oxygen and pH were detected in-situ at six sampling points within each transect approximately one metre above the seafloor. Sediment samples collected was also used to determine particle size. Results: A total of fourteen benthic foraminiferal genera obtained from two major groups belonging to the calcareous and agglutinated groups have been identified at all four sampling locations throughout the sampling period. The abundance of 13 out of 14 species were significantly affected by different sampling sites and times (P<0.05). Physicochemical variables comprising temperature, salinity, dissolved oxygen and pH differed among sites and sampling months (P<0.05).Conclusions:The distribution of foraminifera in terms of abundance and presence of species indicated dominance by calcareous genera of foraminifera contributed by significantly great abundances of Ammonia sp. and relatively low abundance of agglutinated taxa. This pattern of distribution could indicate a close association between foraminifera and physicochemical parameters.

  6. Response of eastern Indian Ocean (ODP Site 762B benthic foraminiferal assemblages to the closure of the Indonesian seaway

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    Ajai Kumar Rai


    Full Text Available Pliocene-Pleistocene deep sea benthic foraminifera from ODP Site 762B in the eastern Indian Ocean were examined to understand the tectonically/climatically induced palaeoceanographic changes. In addition to already published data on this site by Rai & Singh (2001, some more faunal parameters were considered in the present work. Characteristic benthic foraminiferal assemblages as well as more diverse fauna during the early Pliocene (before 3.5 Ma reflected relatively oligotrophic and warm bottom water conditions. At the beginning of the late Pliocene (i.e. ~ 3 ± 0.5 Ma relative abundances of Uvigerina proboscidea, infaunal taxa and high productivity taxa increased, whereas faunal diversity showed a distinct decline, suggesting the development of pronounced upwelling resulting in higher surface water productivity. The strongly reduced inflow of warm and oligotrophic water masses as the South Equatorial Current (SEC from the South Pacific to the eastern Indian Ocean due to the effective closure of the Indonesian seaway increased the surface water productivity. The closing of the Indonesian seaway during the late Pliocene was also responsible for the cessation of the warm, southward-flowing Leeuwin Current (LC and the greater influence of the cold, deep and northward-flowing Western Australian Current (WAC in the eastern Indian Ocean.

  7. Coral Reefs at the Northernmost Tip of Borneo: An Assessment of Scleractinian Species Richness Patterns and Benthic Reef Assemblages. (United States)

    Waheed, Zarinah; van Mil, Harald G J; Syed Hussein, Muhammad Ali; Jumin, Robecca; Golam Ahad, Bobita; Hoeksema, Bert W


    The coral reefs at the northernmost tip of Sabah, Borneo will be established under a marine protected area: the Tun Mustapha Park (TMP) by the end of 2015. This area is a passage where the Sulu Sea meets the South China Sea and it is situated at the border of the area of maximum marine biodiversity, the Coral Triangle. The TMP includes fringing and patch reefs established on a relatively shallow sea floor. Surveys were carried out to examine features of the coral reefs in terms of scleractinian species richness, and benthic reef assemblages following the Reef Check substrate categories, with emphasis on hard coral cover. Variation in scleractinian diversity was based on the species composition of coral families Fungiidae (n = 39), Agariciidae (n = 30) and Euphylliidae (n = 15). The number of coral species was highest at reefs with a larger depth gradient i.e. at the periphery of the study area and in the deep South Banggi Channel. Average live hard coral cover across the sites was 49%. Only 7% of the examined reefs had > 75% hard coral cover, while the majority of the reef sites were rated fair (51%) and good (38%). Sites with low coral cover and high rubble fragments are evidence of blast fishing, although the observed damage appeared old. Depth was a dominant factor in influencing the coral species composition and benthic reef communities in the TMP. Besides filling in the information gaps regarding species richness and benthic cover for reef areas that were previously without any data, the results of this study together with information that is already available on the coral reefs of TMP will be used to make informed decisions on zoning plans for conservation priorities in the proposed park.

  8. Benthic Macrofaunal Assemblage in the Arid Zone Mangroves of Gulf of Kachchh - Gujarat

    Institute of Scientific and Technical Information of China (English)


    The total benthic macrofauna consisting of 62 species in 5 groups, viz. crustaceans (18), gastropods (17), bivalves (16), polychaetes (9) and fishes (2), was recorded in western Kachchh mangroves near Gujarat. The population densities of benthic macrofauna ranged from 424 to 2393 ind.m-2, the diversity ranged from 1.84 to 2.45 bits ind.-1, the richness varied between 0.82 and 0.98, and the evenness varied between 0.64 and 0.81. Two maximum diversity values were recorded during winter and summer. The salinity ranged from 34 to 44, temperature varied between 17 and 37 ℃, and the acidity ranged from 7 to 8.9.

  9. Natural patterns and anthropogenic disturbance in north Adriatic marine benthic assemblages: descriptive and methodological studies



    Marine soft bottom systems show a high variability across multiple spatial and temporal scales. Both natural and anthropogenic sources of disturbance act together in affecting benthic sedimentary characteristics and species distribution. The description of such spatial variability is required to understand the ecological processes behind them. However, in order to have a better estimate of spatial patterns, methods that take into account the complexity of the sedimentary system are required. ...


    Institute of Scientific and Technical Information of China (English)

    陈小华; 康丽娟; 孙从军; 杨青


    Bio assessment of benthic macroinvertebrate-based multmietrics is a very effective approach to evaluate quality of river water. Benthic macroinvertebrate assemblages were sampled at 83 sites in Shanghai metropolitan area, a typical dense river network plain. A total of 20 taxa of the benthic macroinvertebrate were collected, including 50% of Mollusca, 30% of Arthropoda and 20% of Annelida. Among 74 sites with living samples, 32 relatively clean sites and 42 polluted sites were separated based on Hilsenhoff biotic index discrminatory criteria. A comprehensive evaluation using 28 widely-used metrics was carried out. Furthermore, 8 metrics were selected as the most sensitive ones based on non-parametric tests (i.e., Mann-Whitney U test and Kolmogorov-Smirnov test). By standard scoring method, eight sensitive metrics were unified and integrated into a multi-metric index on a scale ranging from 8 to 40 for bioassessment at each site. Biocriteria values for benthic macroinvertebrate were proposed by quartation, i.e., 8-15, very poor; 16-23, poor; 24-31, fair; and 32-40, good. Water quality of 9 sites with no living sample were marked as very poor. According to the biocriteria, 41 typical sites were divided into 5 groups. The past 5-year historical data of physico-chemical water quality indicators have significant difference among 5 group sites. Consequently, the discrminatory biocriteria are suitable for the assessment of the river water quality of the Shanghai City.%2011年夏、秋季在上海市全境主要河流的83个断面进行大型底栖动物的采样,共获取底栖动物20个分类单位(种),其中软体动物、环节动物和节肢动物分别占50%、30% 和20%.选取常见的28个生物指数分别进行计算,并采用非参数统计检验方法筛选出8个敏感生物指数.通过记分法对8种敏感生物指数统一量纲后,获得数值范围为8-40的综合生物指数,运用四分法划分了判别河道水环境质量的生物基准:32-40,

  11. A comparative analysis of benthic nematode assemblages from Zostera noltii beds before and after a major vegetation collapse (United States)

    Materatski, Patrick; Vafeiadou, Anna-Maria; Ribeiro, Rui; Moens, Tom; Adão, Helena


    Benthic nematodes are widely regarded as very suitable organisms to monitor potential ecological effects of natural and anthropogenic disturbances in aquatic ecosystems. During 2008, the seagrass beds of Zostera noltii located in the Mira estuary (SW Portugal) disappeared completely. However, during 2009, slight symptoms of natural recovery were observed, a process which has since evolved intermittently. This study aims to investigate changes in patterns of nematode density, diversity, and trophic composition between two distinct habitat conditions: "before" the collapse of seagrass beds, and during the early recovery "after" the seagrass habitat loss, through the analysis of: i) temporal and spatial distribution patterns of nematode communities, and ii) the most important environmental variables influencing the nematode assemblages. The following hypotheses were tested: i) there would be differences in nematode assemblage density, biodiversity and trophic composition during both ecological conditions, "before" and "after"; and ii) there would be differences in nematode assemblage density, biodiversity and trophic composition at different sampling occasions during both ecological conditions. Nematode density and diversity were significantly different between the two ecological situations. A higher density was recorded before, but a higher diversity was evident after the collapse of Z. noltii. In spite of the disturbance caused by the seagrass habitat loss in the Mira estuary, the nematode trophic composition did not significantly differ between the before and after seagrass collapse situations. Despite the significant differences found among sampling occasions, a consistent temporal pattern was not evident. The response of nematode communities following this extreme event exhibited considerable resistance and resilience to the new environmental conditions.

  12. Baseline assessment of fish communities, benthic macroinvertebrate communities, and stream habitat and land use, Big Thicket National Preserve, Texas, 1999-2001 (United States)

    Moring, J. Bruce


    The Big Thicket National Preserve comprises 39,300 hectares in the form of nine preserve units connected by four stream corridor units (with two more corridor units proposed) distributed over the lower Neches and Trinity River Basins of southeastern Texas. Fish and benthic macroinvertebrate data were collected at 15 stream sites (reaches) in the preserve during 1999–2001 for a baseline assessment and a comparison of communities among stream reaches. The fish communities in the preserve were dominated by minnows (family Cyprinidae) and sunfishes (family Centrarchidae). Reaches with smaller channel sizes generally had higher fish species richness than the larger reaches in the Neches River and Pine Island Bayou units of the preserve. Fish communities in geographically adjacent reaches were most similar in overall community structure. The blue sucker, listed by the State as a threatened species, was collected in only one reach—a Neches River reach a few miles downstream from the Steinhagen Lake Dam. Riffle beetles (family Elmidae) and midges (family Chironomidae) dominated the aquatic insect communities at the 14 reaches sampled for aquatic insects in the preserve. The Ephemeroptera, Plecoptera and Trichoptera (EPT) Index, an index sensitive to water-quality degradation, was smallest at the Little Pine Island Bayou near Beaumont reach that is in a State 303(d)-listed stream segment on Little Pine Island Bayou. Trophic structure of the aquatic insect communities is consistent with the river continuum concept with shredder and scraper insect taxa more abundant in reaches with smaller stream channels and filter feeders more abundant in reaches with larger channels. Aquatic insect community metrics were not significantly correlated to any of the stream-habitat or land-use explanatory variables. The percentage of 1990s urban land use in the drainage areas upstream from 12 bioassessment reaches were negatively correlated to the reach structure index, which indicates

  13. Efeito de metais Cobre (Cu e Zinco (Zn sobre a comunidade de macroinvertebrados bentônicos em riachos do sul do Brasil = The effect of metals (Cu and Zn on the benthic macroinvertebrate community in streams in southern Brazil

    Directory of Open Access Journals (Sweden)

    Silvia Vendruscolo Milesi


    Full Text Available O objetivo deste estudo foi avaliar os efeitos de metais (Cu e Zn sobre a comunidade de macroinverterados bentônicos. Foram amostrados, trimestralmente, entre setembro de 2006 e junho de 2007, organismos e água em oito trechos de riachos de duas bacias hidrográficas influenciadas por urbanização e agricultura. Foram estimados os valores de densidade de organismos, riqueza taxonômica e diversidade de Shannon. Para avaliação dos dados, foram utilizados testes de variância e regressão linear simples. Os resultados demonstraram variabilidade das concentrações dos metais e da macrofauna entre as estações do ano e riachos estudados. O metal Cobre (Cu apresentou influência apenas sobre a densidade Chironomidae e o metal Zinco (Zn apresentou efeito sobre a densidade total da macrofauna bentônica e de Chironomidae. Nenhum dos metais apresentou efeitos sobre ariqueza e diversidade de macroinvertebrados. Os resultados indicam potencial bioindicador da comunidade bentônica na avaliação da qualidade integrada do ambiente.The aim of this study was to evaluate the effect of metals (Cu and Zn on the benthic macroinvertebrate community. The organismsand water were collected quarterly between September 2006 and June 2007, in eight sites in streams of two hydrographic basins, influenced by urbanization and agriculture. The values of organism density, taxonomic richness and the Shannon diversity index were calculated. For data evaluation, tests of variance and simple linear regression were used. The results showed variability in the metal concentration and benthic community among seasons and studied streams. Cu showed influence only on Chironomidae density. Zn demonstrated effect on the benthic community and Chironomidae density. None of the metals presented effect on the macroinvertebrate richness and diversity. The results indicate a bioindicatorpotential of the benthic community in the evaluation of integral quality of the environment.

  14. Interspecific Relationships in Benthic Assemblages of a Large Lowland River : Co-existence or Competition as a Result of Habitat Characteristics (United States)

    Akopian, M.; Usseglio-Polatera, P.


    Macrobenthic assemblages of the lower, regulated and canalized Marne River (France) are dominated by several "exotic", recently introduced species. Arrival, installation and spread of such alien species were certainly promoted by (1) the close connection between French and other European river systems (Rhine, Danube), (2) the modification of natural river flow and benthic habitats. Both habitat characteristics (e.g. granulometric composition, organic content) and corresponding benthic assemblage structure were analysed to identify the substrate affinity of major taxa in the lower Marne River. The main aim of the study was to evaluate the possible biotic interactions (i.e. competition for food and/or space) among dominant taxa as function of habitat features and to predict the future development of newly established species, already known as potential invaders: Corbicula fluminea (Bivalvia), Hypania invalida (Polychaeta), Chelicorophium curvispinum (Amphipoda), etc. Most of the newly established species, coming from the same biogeographical area ("invasional meltdown" hypothesis?), are eurytopic, with high fecundity and large food spectrum. First results demonstrated the co-existence of such species in the Marne River. But the future ecological importance of these organisms in benthic assemblages of the river depends on their present population size, population dynamics, and ability to colonize bottom substrates.

  15. SHE analysis for biozonation of benthic foraminiferal assemblages from western arctic ocean (United States)

    Osterman, L.E.; Buzas, M.A.; Hayek, L.-A.C.


    Benthic foraminiferal species abundance in samples from three Mendeleyev Ridge box cores were analyzed by cluster analysis and the newer method of SHE analysis. Previously, the latter technique only has been used on foraminiferal data from depth transects of modern surface sediment samples. Unlike most methods, which initially compare all possible pairs of samples, the SHE procedure results in a linear pattern if a sequence of samples are from the same statistical distribution. A change in slope indicates a statistical change in community structure and / or a change in species composition. The research reported herein is the first application of SHE for the purpose of identifying biozones in sediment core samples for the purpose of stratigraphic correlation. Both cluster analysis and the SHE method provided zonation within cores. However, the cluster method often produced clusters that were difficult to identify and also contained a mixture of samples without stratigraphic continuity. In contrast, SHE resulted in easily identifiable biozones and ensured temporal continuity within them. In general, the cluster analysis produced more zones than the SHE analysis. About 87% of the cluster zones and 64% of the SHE zones were correlated across more than one core. The average age range for correlated biozone boundaries among the three cores, based on radiocarbon dates, was 821 years using cluster analysis and 296 years using SHE. The sequential nature of the analysis, ease in choosing boundaries, and correlation of these boundaries across cores makes SHE the preferred technique.

  16. Influence of benthic macro-invertebrate bioturbation on the biogeochemical behaviour of uranium within freshwater sediments; Influence de la bioturbation des macro-invertebres benthiques sur le comportement biogeochimique de l'uranium au sein des sediments d'eau douce

    Energy Technology Data Exchange (ETDEWEB)

    Lagauzere, S.


    In freshwater ecosystems, sediments act as an accumulation compartment for metallic pollutants as uranium. Secondary, there can also represent endogenous sources of contamination by resuspension (e.g. flood, bioturbation) or changes of metal speciation that acts upon their bioavailability. Indeed, metallic compounds can be transformed in more or less toxic or inert compounds through physico-chemical (e.g. pH, redox conditions, ionic force) and microbiological variations. These conditions are themselves under the effects of benthic macro-invertebrate activities via bioturbation processes. The main objective of this PhD was to determinate the influence of two benthic macro-invertebrate species (Chironomus riparius and Tubifex tubifex) on the distribution and the transfers of uranium within freshwater sediments. To reach this goal, laboratory experiments were performed in order to (i) assess the effects of uranium on benthic macro-invertebrates, more particularly on their bioturbation activity, (ii) determine the influence of these organisms on uranium behaviour through high resolution physico-chemical measurements (e.g. oxygen optodes, DET gel probes), and (iii) estimate the consequences of these interactions on pelagic organisms via genotoxicity measurements (micronuclei assay and molecular bio-markers analysis on Xenopus laevis). The results demonstrate that bioturbation intensity of macro-invertebrates can be affected in uranium-contaminated sediments, but the two species studied in this work show a relative tolerance. For high uranium concentrations (>100 times the geochemical background level), corresponding however to realistic concentrations in highly contaminated sites, T. tubifex worms are able to maintain a sufficient bioturbation activity that induces a high remobilization of uranium initially associated with sediments to the overlying water (factor 2 to 10). That represents therefore a potential risk for the remaining aquatic biocenose. However, by

  17. Methods of analysis by the U.S. Geological Survey National Water Quality Laboratory; processing, taxonomy, and quality control of benthic macroinvertebrate samples (United States)

    Moulton, Stephen R.; Carter, James L.; Grotheer, Scott A.; Cuffney, Thomas F.; Short, Terry M.


    Qualitative and quantitative methods to process benthic macroinvertebrate (BMI) samples have been developed and tested by the U.S. Geological Survey?s National Water Quality Laboratory Biological Group. The qualitative processing method is based on visually sorting a sample for up to 2 hours. Sorting focuses on attaining organisms that are likely to result in taxonomic identifications to lower taxonomic levels (for example, Genus or Species). Immature and damaged organisms are also sorted when they are likely to result in unique determinations. The sorted sample remnant is scanned briefly by a second person to determine if obvious taxa were missed. The quantitative processing method is based on a fixed-count approach that targets some minimum count, such as 100 or 300 organisms. Organisms are sorted from randomly selected 5.1- by 5.1-centimeter parts of a gridded subsampling frame. The sorted remnant from each sample is resorted by a second individual for at least 10 percent of the original sort time. A large-rare organism search is performed on the unsorted remnant to sort BMI taxa that were not likely represented in the sorted grids. After either qualitatively or quantitatively sorting the sample, BMIs are identified by using one of three different types of taxonomic assessment. The Standard Taxonomic Assessment is comparable to the U.S. Environmental Protection Agency Rapid Bioassessment Protocol III and typically provides Genus- or Species-level taxonomic resolution. The Rapid Taxonomic Assessment is comparable to the U.S. Environmental Protection Agency Rapid Bioassessment Protocol II and provides Familylevel and higher taxonomic resolution. The Custom Taxonomic Assessment provides Species-level resolution whenever possible for groups identified to higher taxonomic levels by using the Standard Taxonomic Assessment. The consistent use of standardized designations and notes facilitates the interpretation of BMI data within and among water-quality studies

  18. Aquatic assemblages of the highly urbanized Santa Ana River Basin, California (United States)

    Brown, L.R.; Burton, C.A.; Belitz, K.


    We assessed the structure of periphyton, benthic macroinvertebrate, and fish assemblages and their associations with environmental variables at 17 sites on streams of the highly urbanized Santa Ana River basin in Southern California. All assemblages exhibited strong differences between highly urbanized sites in the valley and the least-impacted sites at the transition between the valley and undeveloped mountains. Results within the urbanized area differed among taxa. Periphyton assemblages were dominated by diatoms (>75% of total taxa). Periphyton assemblages within the urbanized area were not associated with any of the measured environmental variables, suggesting that structure of urban periphyton assemblages might be highly dependent on colonization dynamics. The number of Ephemeroptera, Trichoptera, and Plecoptera (EPT) taxa included in macroinvertebrate assemblages ranged from 0 to 6 at urbanized sites. Benthic macroinvertebrate assemblages had significant correlations with several environmental variables within the urban area, suggesting that stream size and permanence were important determinants of distribution among the species able to survive conditions in urban streams. Only 4 of 16 fish species collected were native to the drainage. Fish assemblages of urbanized sites included two native species, arroyo chub Gila orcuttii and Santa Ana sucker Catostomus santaanae, at sites that were intermediate in coefficient of variation of bank-full width, depth, bed substrate, and water temperature. Alien species dominated urbanized sites with lesser or greater values for these variables. These results suggest that urban streams can be structured to enhance populations of native fishes. Continued study of urban streams in the Santa Ana River basin and elsewhere will contribute to the basic understanding of ecological principles and help preserve the maximum ecological value of streams in highly urbanized areas.

  19. Relationships among rotational and conventional grazing systems, stream channels, and macroinvertebrates (United States)

    Raymond, K.L.; Vondracek, B.


    Cattle grazing in riparian areas can reduce water quality, alter stream channel characteristics, and alter fish and macroinvertebrate assemblage structure. The U.S. Department of Agriculture, Natural Resources Conservation Services has recommended Rotational Grazing (RG) as an alternative management method on livestock and dairy operations to protect riparian areas and water quality. We evaluated 13 stream channel characteristics, benthic macroinvertebrate larvae (BML), and chironomid pupal exuviae (CPE) from 18 sites in the Upper Midwest of the United States in relation to RG and conventional grazing (CG). A Biotic Composite Score comprised of several macroinvertebrate metrics was developed for both the BML assemblage and the CPE assemblage. Multi-Response Permutation Procedures (MRPP) indicated a significant difference in stream channel characteristics between RG and CG. Nonmetric Multidimensional Scaling indicated that RG sites were associated with more stable stream banks, higher quality aquatic habitat, lower soil compaction, and larger particles in the streambed. However, neither MRPP nor Mann-Whitney U tests demonstrated a difference in Biotic Composite Scores for BML or CPE along RG and CG sites. The BML and CPE metrics were significantly correlated, indicating that they were likely responding to similar variables among the study sites. Although stream channel characteristics appeared to respond to grazing management, BML and CPE may have responded to land use throughout the watershed, as well as local land use. ?? 2011 Springer Science+Business Media B.V. (outside the USA).

  20. Patterns of macroinvertebrate assemblages in a long-term watershed-scale study to address the effects of pulp and paper mill discharges in four US receiving streams. (United States)

    Flinders, Camille A; Minshall, G Wayne; Ragsdale, Renee L; Hall, Timothy J


    Changes in macroinvertebrate communities exposed to pulp and paper mill effluent (PPME) have been seen in mesocosm and short-term field studies. However, long-term patterns of macroinvertebrates in PPME receiving streams have not been examined. We conducted a study of 4 PPME receiving streams (Codorus Creek, PA; the Leaf River, MS; and the McKenzie and Willamette rivers, OR) over 9 y to assess temporal patterns in macroinvertebrate community structure and metrics related to PPME discharge. Study streams represented different ecoregions, warm-/cold-water systems, gradients of PPME concentration (mill process types. Bray-Curtis similarity and nonmetric multidimensional scaling showed significant community differences across sites in Codorus Creek, but differences were related to stream temperature patterns and not PPME. In the other study streams, seasonal community differences across years were greater than differences across sites. General linear models were used to examine spatial and temporal variation in macroinvertebrate metric response (% dominant taxa, density, richness, Hilsenhoff Biotic Index [HBI], Simpson's Index, and ash-free dry mass). Mean HBI scores indicated that the macroinvertebrate community reflected fair to very good water quality conditions, with water quality typically classified as "good" at most sites. Significant site differences in macroinvertebrate metric response were uncommon in the Leaf, McKenzie, and Willamette rivers but were seen in all metrics in Codorus Creek, where metric response was spatially variable. In the McKenzie River, there was an increase in mean HBI scores at sites downstream of the mill relative to 1 of the 2 upstream sites. However, significant differences were seen only between 1 upstream and downstream site, and HBI scores at all downstream sites consistently reflected "good" water quality. Significant annual differences in metric response were typical in all rivers. Water quality (pH, conductivity, total nitrogen

  1. 大型底栖动物在水生态系统健康评价中的应用%The application of benthic macroinvertebrates in aquatic ecosystem health assessment

    Institute of Scientific and Technical Information of China (English)

    王艳杰; 李法云; 范志平; 程志辉; 张建祺


    Benthic macroinvertebrates are the main components of the aquatic ecosystem and play a key role in function and health of aquatic ecosystem.With the increasing emphasis on the aquatic ecosystem management based on watershed integrity in China,the studies on aquatic ecosystem health is more and more detailed,thus the study of benthic macroinvertebrates are improved not only in depth but also in breadth.The main study tasks,impacting factors and analytical methods on benthic macroinvertebrates were summarized at home and abroad in recent years.The results indicate that the response of benthic macroinverebrates to the variation of aquatic ecosystem is significant on the spatial scale,so the effects of natural environment,habitat conditions and water quality on benthic animal diversity and its community structure in the different spatial scales were analyzed.The variations of water environment factors caused by the human activities or the damage of habitat could influence directly the species composition and community features of benthic animal according to the integrated analysis of various factors.The analytical methods on benthic animal could be classified as two types,namely,a model analytical method and a biology index assessment method.Which one is selected in the actual application depends on the features of model and index.%大型底栖动物是维系水生态系统结构和功能的重要组成部分,也是影响水生态系统健康与功能的重要水生生物指标。随着中国对基于流域完整性水生态管理的日益重视,水生态系统健康的研究也更加深入,因而底栖动物的研究在深度和广度上均有所提高。概述了近年来国内外底栖动物的主要研究方向、影响因素及其分析方法。结果表明:在研究方向上,由于底栖动物对水生态系统变化的响应具有明显的空间尺度效应,因而以不同尺度空间上的自然环境、生境条件和水质等因子为分界,分析其对底

  2. Implementation of artificial neural networks (ANNs) to analysis of inter-taxa communities of benthic microorganisms and macroinvertebrates in a polluted stream. (United States)

    Kim, Byunghyuk; Lee, Se-Eun; Song, Mi-Young; Choi, Jung-Hye; Ahn, Soon-Mo; Lee, Kun-Seop; Cho, Eungchun; Chon, Tae-Soo; Koh, Sung-Cheol


    This study was performed to gain an understanding of the structural and functional relationships between inter-taxa communities (macroinvertebrates as consumers, and microbes as decomposers or preys for the invertebrates) in a polluted stream using artificial neural networks techniques. Sediment samples, carrying microorganisms (eubacteria) and macroinvertebrates, were seasonally collected from similar habitats in streams with different levels of pollution. Microbial community taxa and densities were determined using polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) and 16S rDNA sequence analysis techniques. The identity and density of macroinvertebrates were concurrently determined. In general, differences were observed on grouping by self-organizing map (SOM) in polluted, clean and recovering sites based on the microbial densities, while the community patterns were partly dependent on the sampling period. A Spearman rank order correlation analysis revealed correlations of several eubacterial species with those of macroinvertebrates: a negative correlation was observed between Acidovorax sp. (from polluted sites) and Gammaridae (mostly from the clean site), while Herbaspirillum sp. and Janthinobacterium sp. appeared to have positive correlations with some macroinvertebrate species. The population dynamics of the tolerant texa, Tubificidae and Chironomidae, appeared to be related with changes in the densities of Acidovorax sp. This study revealed community relationships between macroinvertebrates and microorganisms, reflecting the connectivity between the two communities via the food chain. A further physio-ecological and symbiological study on the invertebrate-microorganism relationships will be required to understand the degradation and utilization of detritus in aquatic ecosystems as well as to elucidate the roles of the inter-taxa in the recovery of polluted aquatic environments.

  3. Relations of benthic macroinvertebrates to concentrations of trace elements in water, streambed sediments, and transplanted bryophytes and stream habitat conditions in nonmining and mining areas of the upper Colorado River basin, Colorado, 1995-98 (United States)

    Mize, Scott V.; Deacon, Jeffrey R.


    Intensive mining activity and highly mineralized rock formations have had significant impacts on surface-water and streambed-sediment quality and aquatic life within the upper reaches of the Uncompahgre River in western Colorado. A synoptic study by the U.S. Geological Survey National Water-Quality Assessment Program was completed in the upper Uncompahgre River Basin in 1998 to better understand the relations of trace elements (with emphasis on aluminum, arsenic, copper, iron, lead, and zinc concentrations) in water, streambed sediment, and aquatic life. Water-chemistry, streambed-sediment, and benthic macroinvertebrate samples were collected during low-flow conditions between October 1995 and July 1998 at five sites on the upper Uncompahgre River, all downstream from historical mining, and at three sites in drainage basins of the Upper Colorado River where mining has not occurred. Aquatic bryophytes were transplanted to all sites for 15 days of exposure to the water column during which time field parameters were measured and chemical water-quality and benthic macroinvertebrate samples were collected. Stream habitat characteristics also were documented at each site. Certain attributes of surface-water chemistry among streams were significantly different. Concentrations of total aluminum, copper, iron, lead, and zinc in the water column and concentrations of dissolved aluminum, copper, and zinc were significantly different between nonmining and mining sites. Some sites associated with mining exceeded Colorado acute aquatic-life standards for aluminum, copper, and zinc and exceeded Colorado chronic aquatic-life standards for aluminum, copper, iron, lead, and zinc. Concentrations of copper, lead, and zinc in streambed sediments were significantly different between nonmining and mining sites. Generally, concentrations of arsenic, copper, lead, and zinc in streambed sediments at mining sites exceeded the Canadian Sediment Quality Guidelines probable effect level (PEL

  4. The impact of seasonally deposited phytodetritus on epifaunal and shallow infaunal benthic foraminiferal populations in the bathyal northeast Atlantic: the assemblage response (United States)

    Lambshead, P. J. D.; Gooday, A. J.


    The impact of phytodetritus on deep-sea benthic foraminiferal assemblages was studied before and after a detritus drop in 1982 at about 1350 m in the Porcupine Seabight. Assemblage data from the top cm of sediment were analysed by diversity and species distribution methods. Despite its relatively modest organic content, the phytodetritus had a significant impact on the foraminiferal communities. The mix of species changed significantly after the phytodetritus drop, as indicated by species distribution analysis. A number of species displayed a disproportionate population growth in the detritus itself, which was readily detectable by neutral model analysis. In so far as could be determined by the methods employed in this study, the phytodetritus had less impact on those organisms that did not colonize the detritus, but it appeared to be responsible for changes in species composition and may have caused their populations to become more heterogeneous.

  5. Abundance and Diversity of Crypto- and Necto-Benthic Coastal Fish Are Higher in Marine Forests than in Structurally Less Complex Macroalgal Assemblages (United States)

    Thiriet, Pierre D.; Cheminée, Adrien; Guidetti, Paolo; Bianchimani, Olivier; Basthard-Bogain, Solène; Cottalorda, Jean-Michel; Arceo, Hazel; Moranta, Joan; Lejeune, Pierre; Francour, Patrice; Mangialajo, Luisa


    In Mediterranean subtidal rocky reefs, Cystoseira spp. (Phaeophyceae) form dense canopies up to 1 m high. Such habitats, called ‘Cystoseira forests’, are regressing across the entire Mediterranean Sea due to multiple anthropogenic stressors, as are other large brown algae forests worldwide. Cystoseira forests are being replaced by structurally less complex habitats, but little information is available regarding the potential difference in the structure and composition of fish assemblages between these habitats. To fill this void, we compared necto-benthic (NB) and crypto-benthic (CB) fish assemblage structures between Cystoseira forests and two habitats usually replacing the forests (turf and barren), in two sampling regions (Corsica and Menorca). We sampled NB fish using Underwater Visual Census (UVC) and CB fish using Enclosed Anaesthetic Station Vacuuming (EASV), since UVC is known to underestimate the diversity and density of the ‘hard to spot’ CB fish. We found that both taxonomic diversity and total density of NB and CB fish were highest in Cystoseira forests and lowest in barrens, while turfs, that could be sampled only at Menorca, showed intermediate values. Conversely, total biomass of NB and CB fish did not differ between habitats because the larger average size of fish in barrens (and turfs) compensated for their lower densities. The NB families Labridae and Serranidae, and the CB families Blenniidae, Cliniidae, Gobiidae, Trypterigiidae and Scorpaenidae, were more abundant in forests. The NB taxa Diplodus spp. and Thalassoma pavo were more abundant in barrens. Our study highlights the importance of using EASV for sampling CB fish, and shows that Cystoseira forests support rich and diversified fish assemblages. This evidence suggests that the ongoing loss of Cystoseira forests may impair coastal fish assemblages and related goods and services to humans, and stresses the need to implement strategies for the successful conservation and/or recovery

  6. Mid- to late-Holocene environmental evolution of the Loire estuary as observed from sedimentary characteristics and benthic foraminiferal assemblages (United States)

    Durand, M.; Mojtahid, M.; Maillet, G. M.; Proust, J.-N.; Lehay, D.; Ehrhold, A.; Barré, A.; Howa, H.


    We used sedimentological and foraminiferal characteristics of four sedimentary cores, supported by paleogeographical and historical data, to reconstruct the depositional history of the inner Loire estuary (Near Saint-Nazaire, France) and the response of benthic foraminifera to the mid- to late-Holocene marine flooding of the incised valley. These were further used to evaluate the consequent changes in estuarine morphological and hydro-sedimentary patterns during this time period. Our results described significant changes in hydro-sedimentary dynamics over the past 6 kyrs BP. At our location, these changes expressed the combined influence of marine (e.g., tide, storm waves) and fluvial dynamics (e.g., floods), which are linked, on a broader scale, to sea-level variations and the regional climate regime. Three main periods stand out: (1) from 6.0 to 2.5 kyrs BP, when the sea-level rise slowed down, a large brackish bay extended over and around the study area. The fine-grained tidal rythmites recorded north of the Bilho bank (the main tidal bar located in our study area) indicated a calm depositional environment, protected from the main riverine influence. The presence of thick flood deposits from 5.4 to 4.0 kyrs BP near the Bilho bank indicates further the dominance of humid conditions. (2) From 2.5 kyrs BP to 1850 CE (pre-industrial state), sea-level stabilized at its present value, and the pre-existing bay was progressively infilled. North of the Bilho bank, near a major mudflat (Méan), the generally homogenous sedimentation composed of silty muds rich in organic matter indicated a sheltered environment; the main water flow channel being located south of the Bilho bank. Within this overall homogenous sedimentation, foraminiferal assemblages described rather accurately the progressive infilling of the valley (indicated by a decrease in the proportions of outer estuarine species), accompanied with the channelization of the main entering marine currents (tide, storm

  7. Aquatic Habitat Studies on the Lower Mississippi River, River Mile 480 to 530. report 4. Diel Periodicity of Benthic Macroinvertebrate Drift. (United States)


    macroinvertebrate drift by determining: a. The systematic taxa comprising the drift. b. Those taxa predominating, by number, the drift and the relative abundance of...Graptocorixa sp. Neocorixa sp. COLLEMBOLA Isotomidae Isotomurus sp. PLECOPTERA Plecoptera adult LEPIDOPTERA Noctuidae Arzama obligua HYINENOPTERA

  8. Freshwater Macroinvertebrates. (United States)

    Nalepa, T. F.


    Presents a literature review of freshwater biology particularly freshwater macroinvertebrates and their effect on water pollution, covering publications of 1976-77. A list of 158 references is also presented. (HM)

  9. Between-Habitat Variation of Benthic Cover, Reef Fish Assemblage and Feeding Pressure on the Benthos at the Only Atoll in South Atlantic: Rocas Atoll, NE Brazil. (United States)

    Longo, G O; Morais, R A; Martins, C D L; Mendes, T C; Aued, A W; Cândido, D V; de Oliveira, J C; Nunes, L T; Fontoura, L; Sissini, M N; Teschima, M M; Silva, M B; Ramlov, F; Gouvea, L P; Ferreira, C E L; Segal, B; Horta, P A; Floeter, S R


    The Southwestern Atlantic harbors unique and relatively understudied reef systems, including the only atoll in South Atlantic: Rocas atoll. Located 230 km off the NE Brazilian coast, Rocas is formed by coralline red algae and vermetid mollusks, and is potentially one of the most "pristine" areas in Southwestern Atlantic. We provide the first comprehensive and integrative description of the fish and benthic communities inhabiting different shallow reef habitats of Rocas. We studied two contrasting tide pool habitats: open pools, which communicate with the open ocean even during low tides, thus more exposed to wave action; and closed pools, which remain isolated during low tide and are comparatively less exposed. Reef fish assemblages, benthic cover, algal turfs and fish feeding pressure on the benthos remarkably varied between open and closed pools. The planktivore Thalassoma noronhanum was the most abundant fish species in both habitats. In terms of biomass, the lemon shark Negaprion brevirostris and the omnivore Melichtys niger were dominant in open pools, while herbivorous fishes (mainly Acanthurus spp.) prevailed in closed pools. Overall benthic cover was dominated by algal turfs, composed of articulated calcareous algae in open pools and non-calcified algae in closed pools. Feeding pressure was dominated by acanthurids and was 10-fold lower in open pools than in closed pools. Besides different wave exposure conditions, such pattern could also be related to the presence of sharks in open pools, prompting herbivorous fish to feed more in closed pools. This might indirectly affect the structure of reef fish assemblages and benthic communities. The macroalgae Digenea simplex, which is uncommon in closed pools and abundant in the reef flat, was highly preferred in herbivory assays, indicating that herbivory by fishes might be shaping this distribution pattern. The variations in benthic and reef fish communities, and feeding pressure on the benthos between open and

  10. Between-Habitat Variation of Benthic Cover, Reef Fish Assemblage and Feeding Pressure on the Benthos at the Only Atoll in South Atlantic: Rocas Atoll, NE Brazil.

    Directory of Open Access Journals (Sweden)

    G O Longo

    Full Text Available The Southwestern Atlantic harbors unique and relatively understudied reef systems, including the only atoll in South Atlantic: Rocas atoll. Located 230 km off the NE Brazilian coast, Rocas is formed by coralline red algae and vermetid mollusks, and is potentially one of the most "pristine" areas in Southwestern Atlantic. We provide the first comprehensive and integrative description of the fish and benthic communities inhabiting different shallow reef habitats of Rocas. We studied two contrasting tide pool habitats: open pools, which communicate with the open ocean even during low tides, thus more exposed to wave action; and closed pools, which remain isolated during low tide and are comparatively less exposed. Reef fish assemblages, benthic cover, algal turfs and fish feeding pressure on the benthos remarkably varied between open and closed pools. The planktivore Thalassoma noronhanum was the most abundant fish species in both habitats. In terms of biomass, the lemon shark Negaprion brevirostris and the omnivore Melichtys niger were dominant in open pools, while herbivorous fishes (mainly Acanthurus spp. prevailed in closed pools. Overall benthic cover was dominated by algal turfs, composed of articulated calcareous algae in open pools and non-calcified algae in closed pools. Feeding pressure was dominated by acanthurids and was 10-fold lower in open pools than in closed pools. Besides different wave exposure conditions, such pattern could also be related to the presence of sharks in open pools, prompting herbivorous fish to feed more in closed pools. This might indirectly affect the structure of reef fish assemblages and benthic communities. The macroalgae Digenea simplex, which is uncommon in closed pools and abundant in the reef flat, was highly preferred in herbivory assays, indicating that herbivory by fishes might be shaping this distribution pattern. The variations in benthic and reef fish communities, and feeding pressure on the benthos

  11. The Eocene-Oligocene transition at ODP Site 1263, Atlantic Ocean: decreases in nannoplankton size and abundance and correlation with benthic foraminiferal assemblages (United States)

    Bordiga, M.; Henderiks, J.; Tori, F.; Monechi, S.; Fenero, R.; Thomas, E.


    The biotic response of calcareous nannoplankton to environmental and climatic changes during the Eocene-Oligocene transition (~34.8-32.7 Ma) was investigated at high resolution at Ocean Drilling Program (ODP) Site 1263 (Walvis Ridge, South East Atlantic Ocean), and compared with a lower resolution benthic foraminiferal record. During this time interval, the global climate which had been warm during the Eocene, under high levels of atmospheric CO2 (pCO2), transitioned into the cooler climate of the Oligocene, with overall lower pCO2. At Site 1263, the absolute nannofossil abundance (coccoliths per gram of sediment; N g-1) and the mean coccolith size decreased distinctly across the E-O boundary (EOB; 33.89 Ma), mainly due to a sharp decline in abundance of large-sized Reticulofenestra and Dictyococcites, within ~53 kyr. Since carbonate dissolution did not vary much across the EOB, the decrease in abundance and size of nannofossils may highlight an overall decrease in their export production, which could have led to an increased ratio of organic to inorganic carbon (calcite) burial, as well as variations in the food availability for benthic foraminifers. The benthic foraminiferal assemblage data show the global decline in abundance of rectilinear species with complex apertures in the latest Eocene (~34.5 Ma), potentially reflecting changes in the food source, thus phytoplankton, followed by transient increased abundance of species indicative of seasonal delivery of food to the sea floor (Epistominella spp.; ~34.04-33.54 Ma), with a short peak in overall food delivery at the EOB (buliminid taxa; ~33.9 Ma). After Oi-1 (starting at ~33.4 Ma), a high abundance of Nuttallides umbonifera indicates the presence of more corrosive bottom waters, possibly combined with less food arriving at the sea floor. The most important signals in the planktonic and benthic communities, i.e. the marked decrease of large reticulofenestrids, extinctions of planktonic foraminifer species and

  12. Foote Brook Macroinvertebrate Biomonitoring-Phase I in Johnson, Vermont (United States)

    Vermont Center for Geographic Information — The Foote Brook Biomonitoring Project, Phase I geospatial dataset consists of data from the biomonitoring of benthic macroinvertebrates at three sites located along...

  13. The use of rapid bioassessment protocols to describe fish and benthic macroinvertebrate communities in three creeks near the Little River National Wildlife Refuge, McCurtain County, Oklahoma (United States)

    US Fish and Wildlife Service, Department of the Interior — Selected metrics from the Rapid Bioassessment Protocols (RBPs), published by the U.S. Environmental Protection Agency, were used to describe fish and benthic...

  14. Biological assessment of water quality in Chaohu Lake watershed: A case study of benthic macroinvertebrate%巢湖流域水质生物学评价——以大型底栖动物为例

    Institute of Scientific and Technical Information of China (English)

    宁怡; 高峰; 邓建才; 胡维平; 高俊峰; 赵振华


    Due to the long-term exposure to natural environment, benthic macroinvertebrate can integrate the environmental physical, chemical, and biological information at different time scales, and reflect the damaged characteristics under the synergistic effects of pollutants, having been widely used in water health assessment. To understand the present status of water pollution in Chaohu Lake watershed, Anhui Province of East China, an investigation on the benthic macro-invertebrate in the watershed was carried out in April 2009. At 59 sampling sites, a total of 23 benthic macroinvertebrate species were identified, among which, 6 species were of annelids, occupying 26. 1% of the total, and 8 and 9 species were of arthropods and mollusks, occupying 34. 8% and 39. 1% of the total-, respectively. The dominant species varied greatly with the habitats , but Limnodrilus hoffineisteri, Branchiura sowerbyi, and Bellamya aeruginosa were the three dominant taxa. The integrated biological pollution index assessment revealed that the waters in the watershed were polluted in different degrees, and the pollution status was in the order of Nan-fei River > Baishishan River > Paihe River > Chaohu Lake > Zhegao River > Hangbu River > Yuxi River > Fengle River, which was basically in agreement with the water quality index assessment.%由于长期暴露在自然环境中,底栖动物可整合不同时间尺度的物理、化学及生物信息,能反映污染物质对其造成的协同危害特征,因而被广泛应用于水体健康评价.为了弄清巢湖流域水体污染状况,于2009年4月对巢湖流域大型底栖动物进行采样调查.59个采样点中,鉴定出大型底栖动物共23种,其中:环节动物门6种,占26.1%;节肢动物门8种,占34.8%;软体动物门9种,占39.1%.尽管不同栖息环境中底栖动物的优势种有较大变化,但霍甫水丝蚓(Limnodrilus hoffmeisteri)、苏氏尾鳃蚓(Branchiura sowerbyi)和铜锈环棱螺(Bellamya aeruginosa)为

  15. Ensamble de crustáceos bentónicos en un lago salino tropical Benthic crustaceans assemblage in a tropical, saline lake

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    Ma. del Carmen Hernández


    Full Text Available El presente trabajo reconoce la composición, estructura y distribución espacial del ensamble de crustáceos bentónicos de Alchichica, un lago salino tropical ubicado en el extremo oriental del altiplano mexicano. El lago presenta una riqueza taxonómica de crustáceos bentónicos compuesta por 1 anfípodo (Hyalella azteca, 1 isópodo (Caecidotea williamsi y 2 ostrácodos (Limnocythere inopinata y Candona sp.. Comparada con otros lagos tropicales, la riqueza de especies es reducida. A pesar de lo anterior, es importante mencionar el grado elevado de endemismo representado por C. williamsi, recientemente descrita para el lago Alchichica; adicionalmente, es factible que tanto Candona como H. azteca sean especies nuevas y endémicas del lago. Los crustáceos bentónicos se distribuyen desde la zona litoral hasta la zona más profunda del lago (62 m con abundancias y riqueza taxonómica variables. Los ostrácodos fueron los crustáceos que con mayor frecuencia se recolectaron en el lago, en la zona litoral, en el talud, y en la zona profunda de la que son habitantes exclusivos. Los anfípodos constituyeron el segundo grupo en abundancia de la zona litoral y talud y estuvieron ausentes en la zona profunda. Los isópodos sólo se encuentran asociados a los depósitos de tufa, hábitat característico del lago que se extiende a lo largo del talud, por lo que con las técnicas de muestreo tradicional empleadas en el presente estudio no fueron capturados. En este ensamble de crustáceos predominan las especies de desarrollo directo y con posiciones tróficas que incluyen componentes herbívoros (H. azteca, omnívoros (C. williamsi y bacterívoros (L. inopinata y Candona sp..This work acknowledges the composition, structure and spatial distribution of the benthic crustaceans assemblage of Alchichica, a tropical saline lake located in the easternmost portion of the Mexican highlands. The benthic crustaceans' assemblage was comprised by 1 amphipod

  16. Ancient fish and recent invaders: white sturgeon Acipenser transmontanus diet response to invasive-species-mediated changes in a benthic prey assemblage (United States)

    Zeug, Steven C; Brodsky, Annie; Kogut, Nina; Stewart, Robin; Merz, Joe


    Invasive organisms can have significant impacts on native species, and the San Francisco Estuary (SFE), California, USA, is one of the world's most invaded estuaries. Decline of native white sturgeon Acipenser transmontanus abundance in the SFE has been acknowledged, but underlying mechanisms are poorly understood. Invasion by the overbite clam Potamocorbula amurensis has drastically altered the SFE benthic prey community, yet little is known about how this change has affected sturgeon diets. We investigated changes in the diet of white sturgeon following the overbite clam invasion and subsequent shift in the SFE benthic prey assemblage. Gut content analysis was used to compare white sturgeon prey composition and importance between the pre- and post-invasion periods. Additionally, stable isotope analysis was employed to estimate the assimilation of prey items to sturgeon biomass. Overbite clams dominated diets in the post-invasion period, accounting for 82 to 93% of total volume. Stable isotope analysis confirmed the importance of this prey item, although their assimilated contribution to sturgeon biomass was estimated to be less (70 to 83%) than gut contents indicated. The frequency of fish in white sturgeon guts increased in the post-invasion period, and isotope analysis indicated relatively large contributions of fish to sturgeon biomass (3.7 to 19%). The trophic adaptability of white sturgeon has allowed them to exploit this new prey source (overbite clam). Future conservation and restoration efforts must consider a potentially destabilized food web given the large importance of a single prey item.

  17. Western Indian Ocean circulation and climate variability on different time scales. A study based on stable oxygen and carbon isotopes, benthic foraminiferal assemblages and Mg/Ca paleothermometry

    Energy Technology Data Exchange (ETDEWEB)

    Romahn, Sarah


    In order to understand the Earth's climate evolution it is crucial to evaluate the role of low-latitude oceans in the global climate system, as they are connected to both hemispheres via atmospheric and oceanic circulation and thus hold the potential to disentangle the asynchronicity of short-term Pleistocene climate variability. However, the potential of low latitude oceans to respond to and force large-scale changes of the climate system is still debated. The aim of this thesis is to examine and to understand the causal relationship of both atmospheric and oceanic changes in the tropical western Indian Ocean on centennial-, millennial and glacial-interglacial timescales. For this purpose I investigated stable oxygen and carbon isotope compositions of both planktic and benthic foraminiferal tests, Mg/Ca ratios of planktic foraminiferal tests as well as benthic foraminiferal assemblages and sedimentary geochemical parameters on two sediment cores (GeoB12615-4, 446 m and GeoB12616-4, 1449 m) from the continental slope off Tanzania, East Africa.

  18. Changes in planktic and benthic foraminifer assemblages in the Gulf of Lions, off south France: Response to climate and sea level change from MIS 6 to MIS 11 (United States)

    Cortina, Aleix; Sierro, Francisco Javier; Filippelli, Gabriel; Flores, José Abel; Berné, Serge


    A multidisciplinary study involving micropaleontological and geochemical tools was carried out in borehole PRGL1 (Promess 1), with the aim of reconstructing the impact of climate change and sea level variation between 133 ka and 406 ka in the upper slope of the Gulf of Lions. We used factor analysis to obtain three main benthic assemblages related to eutrophic, mesotrophic, and oxygenated environments; planktic foraminifers were grouped as warm-water and cold-turbulent species. These results were compared with records of CaCO3 and major and trace elements (Al, Ca, K, Sr) as well as the C/N ratio of organic matter. Power and cross-spectral analysis showed a straightforward relationship between precession minima and thermal stratification of the water column as well as the occurrence of eutrophic bottom conditions during lowstand periods and mesotrophic environments at times of highstand. These eutrophic-mesotrophic oscillations, usually driven by global eustatic change, also involved regional variations in CaCO3 source to this environment. During periods of precession maxima, enhancement of northwesterly winds increased primary productivity by mixing, enhancing the percentage of cold-turbulent species in the water column and the proportion of oxygenated benthic species on the bottom. During interglacial stages, these events were recorded by lower biogenic carbonate at the expense of higher silicate-related components most likely due to a higher supply from Pyrenees rivers. The record of oxygenated benthic species can be a good proxy to monitor past changes in Winter Intermediate Water dynamics driven by northwesterly winds.

  19. The health of benthic diatom assemblages in lower stretch of a lesser Himalayan glacier-fed river, Mandakini

    Indian Academy of Sciences (India)

    Prakash Nautiyal; Asheesh Shivam Mishra; Jyoti Verma


    This study examines the ecological state of epilithic diatom assemblages along the lower stretch of Mandakini, a glacier-fed Himalayan river. The diatoms were sampled at four stations during winter and summer, only once in each season. Valve counts were obtained from Naphrax mounts prepared from each sample. Assemblages were recorded for each location. The software OMNIDIA Ver. 5.3 was used for computing the ecological values from the sample counts. Normally Achnanthidium spp. dominated the assemblages, except Nitzschia fonticola (Grunow) at S1 (Kund) and Encyonema minutum (Hilse in Rabh) at S4 (Rudraprayag), only during summer. The ecological values revealed that the assemblages were in -mesosaprobic and mésotraphentic states. However, at S4, trophic state was observed to be eutraphentic. Louis Leclercq index indicated that organic pollution was nonexistent, while the anthropogenic eutrophication was low except at S2 (Tilwara) and S3 (Medanpur) in summer and was moderate at S4 in winter characterized by a lean flow. The most abundant indicator taxa for anthropogenic eutrophication are varied; Cymbella tumida (Brebisson-Van Heurck) at S1, Encyonema minutum at S2, S4 while Surirella aungusta (Kutzing) at S3. Ordination showed that the taxa indicating degradation and anthropogenic eutrophication figured as characteristic taxa at respective locations.

  20. Spatial and temporal benthic species assemblage responses with a deployed marine tidal energy device: a small scaled study. (United States)

    Broadhurst, Melanie; Orme, C David L


    The addition of man-made structures to the marine environment is known to increase the physical complexity of the seafloor, which can influence benthic species community patterns and habitat structure. However, knowledge of how deployed tidal energy device structures influence benthic communities is currently lacking. Here we examined species biodiversity, composition and habitat type surrounding a tidal energy device within the European Marine Energy Centre test site, Orkney. Commercial fishing and towed video camera techniques were used over three temporal periods, from 2009 to 2010. Our results showed increased species biodiversity and compositional differences within the device site, compared to a control site. Both sites largely comprised of crustacean species, omnivore or predatory feeding regimes and marine tide-swept EUNIS habitat types, which varied over the time. We conclude that the device could act as a localised artificial reef structure, but that further in-depth investigations are required.

  1. Influence of agricultural, industrial, and anthropogenic stresses on the distribution and diversity of macroinvertebrates in Juru River Basin, Penang, Malaysia. (United States)

    Al-Shami, Salman A; Md Rawi, Che Salmah; Ahmad, Abu Hassan; Abdul Hamid, Suhaila; Mohd Nor, Siti Azizah


    Abundance and diversity of benthic macroinvertebrates as well as physico-chemical parameters were investigated in five rivers of the Juru River Basin in northern Peninsula Malaysia: Ceruk Tok Kun River (CTKR), Pasir River (PR), Permatang Rawa River (PRR), Kilang Ubi River (KUR), and Juru River (JR). The physico-chemical parameters and calculated water quality index (WQI) were significantly different among the investigated rivers (ANOVA, Ppolluted). However, PRR and KUR fell into class IV (polluted). High diversity and abundance of macroinvertebrates, especially the intolerant taxa, Ephemeroptera, Plecoptera, and Trichoptera, were observed in the least polluted river, CTKR. Decreasing abundance of macroinvertebrates followed the deterioration of river water quality with the least number of the most tolerant taxa collected from PR. On the basis of composition and sensitivity of macroinvertebrates to pollutants in each river, the highest Biological Monitoring Working Party (BMWP) index score of 93 was reported in CTKR (good water quality). BMWP scores in PRR and JR were 38.7 and 20.1, respectively, classifying both of them into "moderate water quality" category. Poor water quality was reported in PR and KUR. The outcome of the multivariate analysis (CCA) was highly satisfactory, explaining 43.32% of the variance for the assemblages of macroinvertebrates as influenced by 19 physical and chemical variables. According to the CCA model, we assert that there were three levels of stresses on macroinvertebrate communities in the investigated rivers: Level 1, characterized of undisturbed or slightly polluted as in the case of CTKR; Level 2, characterized by a lower habitat quality (the JR) compared to the CTKR; and Level 3 showed severe environmental stresses (PRR, PR, and KUR) primarily contributed by agricultural, industrial, and municipal discharges.

  2. The effect of thermal pollution on benthic foraminiferal assemblages in the Mediterranean shoreface adjacent to Hadera power plant (Israel). (United States)

    Arieli, Ruthie Nina; Almogi-Labin, Ahuva; Abramovich, Sigal; Herut, Barak


    The thermal pollution patch of Hadera power plant was used as a natural laboratory to evaluate the potential long-term effects of rise in Eastern Mediterranean SST on living benthic foraminifera. Their sensitivity to environmental changes makes foraminifera ideal for this study. Ten monthly sampling campaigns were performed in four stations located along a temperature gradient up to 10 °C from the discharge site of heated seawater to a control station. The SST along this transect varied between 25/18 °C in winter and 36/31 °C in summer. A significant negative correlation was found between SST in all stations and benthic foraminiferal abundance, species richness and diversity. The total foraminiferal abundance and species richness was particularly low at the thermally polluted stations especially during summer when SST exceeded 30 °C, but also throughout the entire year. This indicates that thermal pollution has a detrimental effect on benthic foraminifera, irrelevant to the natural seasonal changes in SST.

  3. Estrutura da comunidade de macroinvertebrados bentônicos de um riacho de serra em Itatinga, São Paulo, Brasil Structure of a benthic macroinvertebrates community in a mountain stream in Itatinga, São Paulo, Brazil

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    Ludmilla O. Ribeiro


    Full Text Available A comunidade de macroinvertebrados bentônicos de um riacho de terceira ordem foi analisada em duas estações do ano, chuvosa e seca. Substratos artificiais foram amostrados semanalmente, ao longo de 56 dias para a coleta de macroinvertebrados, nas duas estações do ano. A composição da comunidade foi caracterizada por uma baixa diversidade, ou seja, presença de muitas espécies raras e poucas espécies abundantes nas duas estações do ano. Uma alta dominância de Chironomidae (Diptera nas duas estações, seguida de Baetidae (Ephemeroptera e Ancylidae (Mollusca, respectivamente nas estações chuvosa e seca, foi característico. Os resultados obtidos reforçam a grande importância de Chironomidae na comunidade bentônica de riachos e salientam a influência da sazonalidade sobre a estruturação destes organismos.The benthic macroinvertebrates community of a third order stream was studied during the wet and dry seasons. The community was analyzed using artificial substrates sampled weekly during 56 days in each season. The community composition was characterized by low species diversity, with high number of rare species and few abundant species for both seasons. A high dominance of Chinonomidae (Diptera for both seasons, followed by Baetidae (Ephemeroptera and Ancylidae (Mollusca, respectively for the wet and dry seasons, was found. The results reinforced the high importance of Chironomidae and the seasonal effect determining the stream benthic community structure.

  4. Evaluation of ecological quality in peri-urban rivers in Mexico City: a proposal for identifying and validating reference sites using benthic macroinvertebrates as indicators

    Directory of Open Access Journals (Sweden)

    Angela Caro-Borrero


    Full Text Available Conservation and management of aquatic ecosystems that are significantly influenced by urban activities requires the classification and establishment of potential reference sites. However, in Latin American countries, policies are not available that outlines the identification and evaluation of such sites. Therefore, this study represents a proposal for evaluating the ecological quality of peri-urban rivers in the conservation soil (CS areas/zones of Mexico City. The proposal accounts for the zone’s physicochemical, hydromorphological, and bacteriological characteristics along with its macroinvertebrate richness. Our evaluation was performed using a canonical correspondence analysis (CCA and indicator values (IndVal calculated for different species. River headwaters serve/work as a good physicochemical point for potential references sites. However, the hydromorphology of the CS has been gradually modified by numerous hydraulic alterations within the peri-urban zone. Using the CCA and IndVal, two types of sites were confirmed: sites in a good state of conservation and quality and sites modified by human activity, featuring lower discharge flow, poor quality hydromorphological values and Oligochaeta class organisms. At the sites featuring a good state of conservation and quality, higher hydromorphological values were positively correlated with discharge flow and certain macroinvertebrate taxa, including Nemouridae, Podonominae, Tanypodinae, Acarina, Baetis, Tipula, Antocha, Atopsyche, Glossosoma, Polycentropus, Hesperophylax and Limnephilus. In the sites modified by human activity, the genus Simulium was classified as a disturbance-tolerant organism. The river reach within the urban zone is basically an open-air drainage ditch. Evaluations of the ecological quality of the riparian zone were used to identify the most important hydromorphological qualities and discharge flow parameters and to select the most appropriate factors that should be

  5. Unusual algal turfs associated with the rhodophyta Phyllophora crispa: Benthic assemblages along a depth gradient in the Central Mediterranean Sea (United States)

    Bonifazi, Andrea; Ventura, Daniele; Gravina, Maria Flavia; Lasinio, Giovanna Jona; Belluscio, Andrea; Ardizzone, Gian Domenico


    Macroalgal assemblages dominated by the turf-forming alga Phyllophora crispa are described in detail for the first time in the Central Mediterranean Sea. This particular form of algal growth, which comprises an upper mixed layer of multiple algal species with a basal stratum formed by entangled thalli of P. crispa, was observed for the first time in 2012 along the promontory of Punta del Lazzaretto (Giglio Island, Italy). In this study, this assemblage was analysed to document the diversity of macroalgae and invertebrate associated communities and assess their distribution along a depth gradient. The algae forming turfs grow directly on the rock at low depth up to 10-15 m depth, while they grow above P. crispa from 15 m to 35 m depth, resulting in luxuriant beds covering up to 100% of the substrate. Multivariate analysis revealed clear differences regarding algae and invertebrate species richness and abundance between shallow and deep strata because of the dominance of Phyllophora crispa at depths greater than 20 m. The long laminal thalli of P. crispa favoured sessile fauna colonization, while the vagile species were principally linked to the architectural complexity of the turf layer created by the P. crispa, which increased the microhabitat diversity and favoured sediment deposition within the turf layer. The complex structures of these turf assemblages and their widespread distribution along the whole coast of the island suggest a well-established condition of the communities linked to the high natural sedimentation rate observed in the area.

  6. Estimation and application of indicator values for common macroinvertebrate genera and families of the United States (United States)

    Carlisle, D.M.; Meador, M.R.; Moulton, S.R.; Ruhl, P.M.


    Tolerance of macroinvertebrate taxa to chemical and physical stressors is widely used in the analysis and interpretation of bioassessment data, but many estimates lack empirical bases. Our main objective was to estimate genus- and family-level indicator values (IVs) from a data set of macroinvertebrate communities, chemical, and physical stressors collected in a consistent manner throughout the United States. We then demonstrated an application of these IVs to detect alterations in benthic macroinvertebrate assemblages along gradients of urbanization in New England and Alabama. Principal components analysis (PCA) was used to create synthetic gradients of chemical stressors, for which genus- and family-level weighted averages (WAs) were calculated. Based on results of PCA, WAs were calculated for three synthetic gradients (ionic concentration, nutrient concentration, and dissolved oxygen/water temperature) and two uncorrelated physical variables (suspended sediment concentration and percent fines). Indicator values for each stress gradient were subsequently created by transforming WAs into ten ordinal ranks based on percentiles of values across all taxa. Mean IVs of genera and families were highly correlated to road density in Alabama and New England, and supported the conclusions of independent assessments of the chemical and physical stressors acting in each geographic area. Family IVs were nearly as responsive to urbanization as genus IVs. The limitations of widespread use of these IVs are discussed.

  7. Changes of benthic bacteria and meiofauna assemblages during bio-treatments of anthracene-contaminated sediments from Bizerta lagoon (Tunisia). (United States)

    Ben Said, Olfa; Louati, Hela; Soltani, Amel; Preud'homme, Hugues; Cravo-Laureau, Cristiana; Got, Patrice; Pringault, Olivier; Aissa, Patricia; Duran, Robert


    Sediments from Bizerta lagoon were used in an experimental microcosm setup involving three scenarios for the bioremediation of anthracene-polluted sediments, namely bioaugmentation, biostimulation, and a combination of both bioaugmentation and biostimulation. In order to investigate the effect of the biotreatments on the benthic biosphere, 16S rRNA gene-based T-RFLP bacterial community structure and the abundance and diversity of the meiofauna were determined throughout the experiment period. Addition of fresh anthracene drastically reduced the benthic bacterial and meiofaunal abundances. The treatment combining biostimulation and bioaugmentation was most efficient in eliminating anthracene, resulting in a less toxic sedimentary environment, which restored meiofaunal abundance and diversity. Furthermore, canonical correspondence analysis showed that the biostimulation treatment promoted a bacterial community favorable to the development of nematodes while the treatment combining biostimulation and bioaugmentation resulted in a bacterial community that advantaged the development of the other meiofauna taxa (copepods, oligochaetes, polychaetes, and other) restoring thus the meiofaunal structure. The results highlight the importance to take into account the bacteria/meiofauna interactions during the implementation of bioremediation treatment.

  8. Evaluation of the ecological effects of heavy metals on the assemblages of benthic foraminifera of the canals of Aveiro (Portugal) (United States)

    Martins, V.; da Silva, E. Ferreira; Sequeira, C.; Rocha, F.; Duarte, A. C.


    Aveiro is a town with 80,000 inhabitants situated in the central west coast of Portugal. It is located at the centre of the Ria de Aveiro, a coastal lagoon that functions as a multi-estuarine area. This town is crossed by several canals which are connected with lagoon channels through canal locks. The operation of the canal locks influences the hydro dynamism in Aveiro's canal and this and other human activities have left a sedimentary record. The study of these records was based on the sediments grain size and composition, mineralogy (by XRD techniques), geochemical (by ICP-MS), total organic carbon (TOC), and microfaunal (benthic foraminifera) content in 15 grab-samples collected in 2006 in Aveiro's canal. The total elemental concentrations evaluated by total digestion of the sediment fraction canals, related to legacies of past industrial activities. These "hot spots" have, for instance, higher available concentrations of Al, Cd, Co, Cu, Fe, Pb, Mn and Zn (evaluated by sequential chemical extractions) and are located in Paraíso, Alboi, Botirões and Cojo Canals, at sites where the sediments are finer and richer in TOC. Abiotic and biotic variables submitted to principal component analysis and cluster analysis highlights the hydrodynamics and human effects on the system and the negative influence of pollutants on the benthic organisms (foraminifera).

  9. Structural and functional effects of conventional and low pesticide input crop-protection programs on benthic macroinvertebrate communities in outdoor pond mesocosms. (United States)

    Auber, Arnaud; Roucaute, Marc; Togola, Anne; Caquet, Thierry


    The impacts of current and alternative wheat crop protection programs were compared in outdoor pond mesocosms in a 10-month long study. Realistic exposure scenarios were built based upon the results of modelling of drift, drainage and runoff of pesticides successively applied under two environmental situations characteristics of drained soils of northern France. Each situation was associated to two crop protection programs ("Conventional" and "Low-input") differing in the nature of pesticides used, number of treatments and application rate. Both programs induced significant direct negative effects on various invertebrate groups. Bifenthrin and cyprodynil were identified as the main responsible for these effects in conventional and low-input program, respectively. Indirect effects were also demonstrated especially following treatments with cyprodynil. Litter breakdown was significantly reduced in all treated mesocosms as the functional consequence of the decrease in the abundance of shredders (asellids, Gammarus pulex) illustrating the link between structural and functional effects of pesticides on macroinvertebrate communities. Recovery was observed for many taxa before the end of the study but not for the most sensitive non mobile taxa such as G. pulex. No influence of the agropedoclimatic situation on the effects was shown, suggesting than the main impacts were associated to inputs from drift. The results confirm that the proposed low-input program was less hazardous than the conventional program but the observed structural and functional impact of the low-input program suggest that further improvement of alternative crop protection programs is still needed.

  10. Assessing the performance of macroinvertebrate metrics in the Challhuaco-Ñireco System (Northern Patagonia, Argentina

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    Melina Mauad


    Full Text Available ABSTRACT Seven sites were examined in the Challhuaco-Ñireco system, located in the reserve of the Nahuel Huapi National Park, however part of the catchment is urbanized, being San Carlos de Bariloche (150,000 inhabitants placed in the lower part of the basin. Physico-chemical variables were measured and benthic macroinvertebrates were collected during three consecutive years at seven sites from the headwater to the river outlet. Sites near the source of the river were characterised by Plecoptera, Ephemeroptera, Trichoptera and Diptera, whereas sites close to the river mouth were dominated by Diptera, Oligochaeta and Mollusca. Regarding functional feeding groups, collector-gatherers were dominant at all sites and this pattern was consistent among years. Ordination Analysis (RDA revealed that species assemblages distribution responded to the climatic and topographic gradient (temperature and elevation, but also were associated with variables related to human impact (conductivity, nitrate and phosphate contents. Species assemblages at headwaters were mostly represented by sensitive insects, whereas tolerant taxa such as Tubificidae, Lumbriculidae, Chironomidae and crustacean Aegla sp. were dominant at urbanised sites. Regarding macroinvertebrate metrics employed, total richness, EPT taxa, Shannon diversity index and Biotic Monitoring Patagonian Stream index resulted fairly consistent and evidenced different levels of disturbances at the stream, meaning that this measures are suitable for evaluation of the status of Patagonian mountain streams.

  11. The benthic marine assemblages of the estuarine and shallow marine Upper Burdigalian deposits of the Korneuburg Basin in Lower Austria (United States)

    Hengst, Babette; Zuschin, Martin; Harzhauser, Mathias; Mandic, Oleg; Roetzel, Reinhard


    In the course of highway constructions (Wiener Außenring-Schnellstraße (S1)) a detailed sedimentological transect of 1.8 km length was logged in deposits of the Central Paratethys near the village of Stetten, N of Korneuburg in Lower Austria. A total of 324 sediment- and 118 molluscan samples was studied. The siliciclastic succession consists of pelitic and sandy sediments and sandstones and is rich in fossils. The fossil remains consist of sponges, corals, serpulids, molluscs, balanids, echinoderms, fish and micromammals. Quantitatively the molluscs dominate and have been studied in detail. 139 species were determined from more than 11,000 shells. Two gastropod species, Agapilia pachii und Granulolabium bicinctum make up more than 53% of the assemblage. Another 11 species (Nassarius edlaueri, Bittium spina, Loripes dujardini, Hydrobia spp., Paphia subcarinata, Cyllenina ternodosa, Turritella gradata, Corbula gibba, Cerastoderma praeplicata, Striarca lactea, Sandbergeria perpusilla) each contributes more than 1% to the total molluscan composition, but all other 126 species are quantitatively unimportant. A conspicuous alternation between intertidal and shallow subtidal mollusc associations is evident. The intertidal is dominated by the superabundant Agapilia pachii and Granulolabium plicatum, whereas the heavily bioturbated fully marine subtidal is characterized by a more diverse assemblage including Turritella gradata, Nassarius edlaueri, Anadara diluvii and various venerids. Additionally, layers with large fragments of Crassostrea and thin coal deposits with Terebralia bidentata are quite abundant in the section. Washed in land snails (e.g., Planorbidae) and river snails (Melanopsidae) occur occasionally. This faunal composition, along with its typical alternation points to a vivid dynamic within this Lower Miocene, subtropical ecosystem in the paleo-estuary of the southern Korneuburg basin.

  12. Impact of oil-based drill mud disposal on benthic foraminiferal assemblages on the continental margin off Angola (United States)

    Jorissen, F. J.; Bicchi, E.; Duchemin, G.; Durrieu, J.; Galgani, F.; Cazes, L.; Gaultier, M.; Camps, R.


    In order to assess the possible environmental impact of oily cuttings discharged during oil exploration activities, we studied the benthic foraminiferal faunas in a five-station, 4-km-long sampling transect around a cuttings disposal site at about 670 m depth offshore Angola (W Africa), where drilling activities started 1.5 years before sampling. Living (Rose Bengal stained) and dead foraminiferal faunas were sampled in March 2006. The faunal patterns mirror the spatial distribution of hydrocarbons, which are dispersed into a southeastern direction. Four different areas can be distinguished on the basis of the investigated faunal parameters (density, diversity and species composition of the living fauna, and comparison with subrecent dead faunas). The fauna at station S31, 300 m SE of the oil cuttings disposal site, appears to be clearly impacted: the faunal density and diversity are maximal, but evenness is minimal. Taxa sensitive to organic enrichment, such as Uvigerina peregrina, Cancris auriculus and Cribrostomoides subglobosus, have largely disappeared, whereas the low-oxygen-resistant taxon Chilostomella oolina and opportunistic buliminids and bolivinids attain relatively high densities. At station S32, 500 m SE of the disposal site, environmental impact is still perceptible. The faunal density is slightly increased, and U. peregrina, apparently the most sensitive species, is still almost absent. The faunas found at 1 and 1.8 km SE of the disposal site are apparently no longer impacted by the drill mud disposal. Faunal density and diversity are low, and the faunal composition is typical for a mesotrophic to eutrophic upper slope environment. Finally, Station S35, 2 km NW of the disposal site, contains an intermediate fauna, where both the low-oxygen-resistant C. oolina and the more sensitive taxa ( U. peregrina, C. auriculus and C. subglobosus) are present. All taxa live close to the sediment-water interface here, indicating a reduced oxygen penetration into

  13. Temporal changes in taxonomic and functional diversity of fish assemblages downstream from mountaintop mining (United States)

    Hitt, Nathaniel P.; Chambers, Douglas B.


    Mountaintop mining (MTM) affects chemical, physical, and hydrological properties of receiving streams, but the long-term consequences for fish-assemblage structure and function are poorly understood. We sampled stream fish assemblages using electrofishing techniques in MTM exposure sites and reference sites within the Guyandotte River basin, USA, during 2010–2011. We calculated indices of taxonomic diversity (species richness, abundance, Shannon diversity) and functional diversity (functional richness, functional evenness, functional divergence) to compare exposure and reference assemblages between seasons (spring and autumn) and across years (1999–2011). We based temporal comparisons on 2 sites that were sampled during 1999–2001 by Stauffer and Ferreri (2002). Exposure assemblages had lower taxonomic and functional diversity than reference assemblages or simulated assemblages that accounted for random variation. Differences in taxonomic composition between reference and exposure assemblages were associated with conductivity and aqueous Se concentrations. Exposure assemblages had fewer species, lower abundances, and less biomass than reference assemblages across years and seasons. Green Sunfish (Lepomis cyanellus) and Creek Chub (Semotilus atromaculatus) became numerically dominant in exposure assemblages over time because of their persistence and losses of other taxa. In contrast, species richness increased over time in reference assemblages, a result that may indicate recovery from drought. Mean individual biomass increased as fish density decreased and most obligate invertivores were apparently extirpated at MTM exposure sites. Effects of MTM were not related to physical-habitat conditions but were associated with water-quality variables, which may limit quality and availability of benthic macroinvertebrate prey. Simulations revealed effects of MTM that could not be attributed to random variation in fish assemblage structure.

  14. Construction of habitat suitability models(HSMs)for benthic macroinvertebrate and their applications to instream environmental flows:A case study in Xiangxi River of Three Gorges Reservior region,China

    Institute of Scientific and Technical Information of China (English)

    Fengqing Li; Qinghua Cai; Xiaocheng Fu; Jiankang Liu


    Based on a long-term ecological monitoring,the present study chose the most dominant benthic macroinvertebrate(Baetis spp.)as tar-get organisms in Xiangxi River,built the habitat suitability models(HSMs)for water depth,current velocity and substrate,respectively,which is the first aquatic organisms model for habitat suitability in the Chinese Mainland with a long-term consecutive in situ measurement.In order to protect the biointegrity and function of the river ecosystem,the theory system of instream environmental flow should be categorized into three hierarchies, namely minimum required instream flow(hydrological level),minimum instream environmental flow(bio-species level),and optimum instream environmental flow(ecosystem level).These three hierarchies of instream environmental flow models were then constructed with the hydropogical and seighted usable area(WUA)method.The results show that the minimum required instream flow of Yiangxi River calculated by the Tennant method(10% of the mean annual flow)was 0.615m3s-1;the minimum instream environmental flow accounted for 19.22% of the mean annual flow(namely 1.182m3s-1),which was the damaged river channel flow in the dry season;and 42.91% of the mean annual flow(namely 2.639m3s-1)should be viewed as the optimum instream environmental flow in order to protect the health of the river ecosystem,maintain the instream biodiversity,and reduce the impact of small hydropower stations nearby the Xiangxi River.We recommend that the hydrological and biological methods can help establish better instream environmental flow models and design best management practices for use in the small hydropower station project.

  15. Effects of streambank fencing of pasture land on benthic macroinvertebrates and the quality of surface water and shallow ground water in the Big Spring Run basin of Mill Creek watershed, Lancaster County, Pennsylvania, 1993-2001 (United States)

    Galeone, Daniel G.; Brightbill, Robin A.; Low, Dennis J.; O'Brien, David L.


    Streambank fencing along stream channels in pastured areas and the exclusion of pasture animals from the channel are best-management practices designed to reduce nutrient and suspended-sediment yields from drainage basins. Establishment of vegetation in the fenced area helps to stabilize streambanks and provides better habitat for wildlife in and near the stream. This study documented the effectiveness of a 5- to 12-foot-wide buffer strip on the quality of surface water and near-stream ground water in a 1.42-mi2 treatment basin in Lancaster County, Pa. Two miles of stream were fenced in the basin in 1997 following a 3- to 4-year pre-treatment period of monitoring surface- and ground-water variables in the treatment and control basins. Changes in surface- and ground-water quality were monitored for about 4 years after fence installation. To alleviate problems in result interpretation associated with climatic and hydrologic variation over the study period, a nested experimental design including paired-basin and upstream/downstream components was used to study the effects of fencing on surface-water quality and benthic-macroinvertebrate communities. Five surface-water sites, one at the outlet of a 1.77-mi2 control basin (C-1), two sites in the treatment basin (T-3 and T-4) that were above any fence installation, and two sites (one at an upstream tributary site (T-2) and one at the outlet (T-1)) that were treated, were sampled intensively. Low-flow samples were collected at each site (approximately 25-30 per year at each site), and stormflow was sampled with automatic samplers at all sites except T-3. For each site where stormflow was sampled, from 35 to 60 percent of the storm events were sampled over the entire study period. Surface-water sites were sampled for analyses of nutrients, suspended sediment, and fecal streptococcus (only low-flow samples), with field parameters (only low-flow samples) measured during sample collection. Benthic-macroinvertebrate samples

  16. Concentrations of metals in water, sediment, biofilm, benthic macroinvertebrates, and fish in the boulder river watershed, Montana, and the role of colloids in metal uptake (United States)

    Farag, A.M.; Nimick, D.A.; Kimball, B.A.; Church, S.E.; Harper, D.D.; Brumbaugh, W.G.


    To characterize the partitioning of metals in a stream ecosystem, concentrations of trace metals including As, Cd, Cu, Pb, and Zn were measured in water, colloids, sediment, biofilm (also referred to as aufwuchs), macroinvertebrates, and fish collected from the Boulder River watershed, Montana. Median concentrations of Cd, Cu, and Zn in water throughout the watershed exceeded the U.S. EPA acute and chronic criteria for protection of aquatic life. Concentrations of As, Cd, Cu, Pb, and Zn in sediment were sufficient in the tributaries to cause invertebrate toxicity. The concentrations of As, Cu, Cd, Pb, and Zn in invertebrates from lower Cataract Creek (63, 339, 59, 34, and 2,410 ??g/g dry wt, respectively) were greater than the concentrations in invertebrates from the Clark Fork River watershed, Montana (19, 174, 2.3, 15, and 648 ??g/g, respectively), that were associated with reduced survival, growth, and health of cutthroat trout fed diets composed of those invertebrates. Colloids and biofilm seem to play a critical role in the pathway of metals into the food chain and concentrations of As, Cu, Pb, and Zn in these two components are significantly correlated. We suggest that transfer of metals associated with Fe colloids to biological components of biofilm is an important pathway where metals associated with abiotic components are first available to biotic components. The significant correlations suggest that Cd, Cu, and Zn may move independently to biota (biofilm, invertebrates, or fish tissues) from water and sediment. The possibility exists that Cd, Cu, and Zn concentrations increase in fish tissues as a result of direct contact with water and sediment and indirect exposure through the food chain. However, uptake through the food chain to fish may be more important for As. Although As concentrations in colloids and biofilm were significantly correlated with As water concentrations, As concentrations in fish tissues were not correlated with water. The pathway for

  17. 流域景观类型及配置对大型底栖动物完整性的影响%The impact of landscape class and patterns on benthic macroinvertebrate index of biological integrity (B-IBI) at the watershed scale

    Institute of Scientific and Technical Information of China (English)

    张海萍; 武大勇; 王赵明; 孙然好; 陈利顶


    Riverine ecosystems are increasingly threatened by human activities and are generally under-protected globally. Various chemical, hydrological, geophysical, and biological indicators can be used to monitor and assess different aspects of river ecosystems. Attention is increasingly been paid to the inclusion of biological indicators in watershed monitoring and assessment. Benthic macroinvertebrates has many advantages over fish and algae, and have become the most popular biological indicators of river health. The Benthic Macroinvertebrate Index of Biological Integrity ( B-IBI) has a wide range of applications to river health assessment and restoration. Examining the relationships between B-IBI and human activities at the landscape scale is important for watershed management. Compared to local indicators, including physical and chemical factors, GIS ( Geographic Information System) data have become increasingly convenient and accessible for landscape-scale assessments of the impacts of human activities on river ecosystems. The use of GIS data instead of direct field measurements is justified based on the assumption that the density of human disturbances is the primary factor contributing to changes in freshwater ecosystems. The relative status of river ecosystems can be predicted by focusing on the drivers of change, rather than field data. In this study, we focused on the relationship between landscape indices and B-IBI. Using environmental and biotic data from 66 sites within the Luan River Basin, the aims of the study were to develop groups of landscape indices and to explore which landscape index bet reflected B-IBI results. Macroinvertebrate assemblages were collected using D-frame nets. Water chemistry and physical parameters were measured at the reach scale. In this study, eight relatively intact reference sites and eight sites showing signs of human impacts were selected to construct the B-IBI index. Reference and impacted sites were selected based on their

  18. Efeito de metais Cobre (Cu e Zinco (Zn sobre a comunidade de macroinvertebrados bentônicos em riachos do sul do Brasil - DOI: 10.4025/actascibiolsci.v30i3.677 The effect of metals (Cu and Zn on the benthic macroinvertebrate community in streams in southern Brazil - DOI: 10.4025/actascibiolsci.v30i3.677

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    Luiz Ubiratan Hepp


    Full Text Available O objetivo deste estudo foi avaliar os efeitos de metais (Cu e Zn sobre a comunidade de macroinverterados bentônicos. Foram amostrados, trimestralmente, entre setembro de 2006 e junho de 2007, organismos e água em oito trechos de riachos de duas bacias hidrográficas influenciadas por urbanização e agricultura. Foram estimados os valores de densidade de organismos, riqueza taxonômica e diversidade de Shannon. Para avaliação dos dados, foram utilizados testes de variância e regressão linear simples. Os resultados demonstraram variabilidade das concentrações dos metais e da macrofauna entre as estações do ano e riachos estudados. O metal Cobre (Cu apresentou influência apenas sobre a densidade Chironomidae e o metal Zinco (Zn apresentou efeito sobre a densidade total da macrofauna bentônica e de Chironomidae. Nenhum dos metais apresentou efeitos sobre a riqueza e diversidade de macroinvertebrados. Os resultados indicam potencial bioindicador da comunidade bentônica na avaliação da qualidade integrada do ambiente.The aim of this study was to evaluate the effect of metals (Cu and Zn on the benthic macroinvertebrate community. The organisms and water were collected quarterly between September 2006 and June 2007, in eight sites in streams of two hydrographic basins, influenced by urbanization and agriculture. The values of organism density, taxonomic richness and the Shannon diversity index were calculated. For data evaluation, tests of variance and simple linear regression were used. The results showed variability in the metal concentration and benthic community among seasons and studied streams. Cu showed influence only on Chironomidae density. Zn demonstrated effect on the benthic community and Chironomidae density. None of the metals presented effect on the macroinvertebrate richness and diversity. The results indicate a bioindicator potential of the benthic community in the evaluation of integral quality of the environment.

  19. Preliminary results in larger benthic foraminifera assemblage in a mixed siliciclastic-carbonate platform from the Upper Cretaceous of the External Prebetic Domain (Valencia province, SE Spain) (United States)

    Robles-Salcedo, Raquel; Vicedo, Vicent


    In the External Prebetic Domain (Betic Mountain Range, Valencia province, SE Spain) it is difficult to find good outcrops to study larger benthic foraminifera (LBF), particularly in the Upper Cretaceous deposits, because of three main reasons. During the Upper Cretaceous, the complex paleogeography in the northern Prebetic Domain developed a complex system of shallow-water platforms. This is directly linked to the complexity in the distribution of the facies observed nowadays, which may change drastically in lateral, closely related outcrops having a special negative impact in the lateral extension of stratigraphical levels containing LBF. The second reason is the nature of the shallow water environments in which the larger foraminifera lived. The local continental influence derived in the establishment of very complex mixed platforms. Thus, there is not a complete register through carbonate rocks, but an alternation of microconglomerates, sandstones, calcarenites and carbonates that can be observed in the stratigraphic series of the Upper Cretaceous. This affects negatively in observing changes in the evolutionary trends of taxa. The third reason difficulting the study of LBF in northern localities of the Prebetic Domain is diagenetic. Dolomitization affects a huge part of the Mesozoic rocks deleting all fossil microfauna in the affected rocks. Such three reasons are behind the difficulty in developing correlations and having a comprehensive understanding of the biostratigraphy and phylogeny of the taxa involved. However, after several field trips developed in the northern Prebetic area, an excellent reference section for the study of the LBF in the Prebetic Domain has been identified in the surroundings of the Pinet village (Valencia province). Here, a relatively continuous section with scarce dolomitization and good conditions of accessibility exists. The larger foraminifera assemblages appering in the Pinet section will be compared with other paleobiogeographic

  20. Riparian leaf litter processing by benthic macroinvertebrates in a woodland stream of central Chile Procesamiento de detritus ripariano por macroinvertebrados bentónicos en un estero boscoso de Chile central

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    Full Text Available Leaf litter input from riparian landscapes has been identified as both a major energy flow to stream ecosystems and as a food source for stream macroinvertebrates. In riparian landscapes of woodland streams of central Chile, the native deciduous hardwoods are being artificially replaced by exotic coniferous trees at a large spatial scale. It is suggested that this process has a significant impact on the stream communities of central Chile. Today, exotic plantations occur throughout central Chile, with Pinus radiata (D. Don (Monterrey pine accounting for about 80 % of the more than 1,800,000 ha of exotic forests. The objective of this paper was to analyze the effect of the litter beds of a dominant native species (Nothofagus pumilio and an exotic species (P. radiata on the detritus processing carried out by benthic macroinvertebrates, in an experimental catchment of central Chile (Rucúe Creek; 36° 26'00" S, 71° 35'40" W. Results revealed that processing rates of native leaf packs are higher than rates of coniferous leaf packs, suggesting that the replacement of the native hardwoods by exotic coniferous riparian flora has an important impact on the stream energy flow in central Chile. The decay rate coefficients (k were 0.0072 for N. pumilio, and 0.0027 for P. radiata. The greater abundance and biomass of shredders per gram of leaf pack of native Nothofagus would explain the differences in leaf processing rates, especially through the activity of two Plecoptera Gripopterygidae, Limnoperla jaffueli and Antarctoperla michaelseniLa entrada de detritus foliar procedente de áreas riparianas ha sido reconocido como un componente importante en la energética de ecosistemas fluviales y como fuente de alimento de macroinvertebrados acuáticos. En áreas riparianas de esteros boscosos de Chile central los componentes nativos caducifolios están siendo artificialmente reemplazados a gran escala por coníferas exóticas, sugiriendo que este proceso tiene

  1. Benthic Flux of Dissolved Nickel into the Water Column of South San Francisco Bay (United States)


    Phosphorous (N:P) Benthic Flux Ratio Fig. 9 – Incubation Core Design Fig. 10 – Macroinvertebrate Taxonomy Fig. 11 – Benthic Chlorophyll Analyses Fig...l a r F l u x R a t i o Redfield Ratio Incubation Core Design Fig. 9 Benthic Macroinvertebrate Taxonomy Fig. 10 Benthic Chlorophyll...98 25-May-99 08-Apr-98 15-Sep-98 25-May-99 Phylum Mollusca Class Bivalvia Potamocorbula amurensis 520 303 195 Musculista senhousia 43 130 Mya

  2. The benthic macroinvertebrate fauna of highland streams in southern Brazil: composition, diversity and structure Fauna de macro-invertebrados bentônicos de rios de montanha no sul do Brasil: composição, diversidade e estrutura

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    Ludwig Buckup


    Full Text Available Benthic macroinvertebrate in four rivers, three in the Pelotas River basin (Divisa, Marco and Silveira rivers, in the headwaters of the Uruguai River and one in the Taquari-Antas system (Antas River, a tributary in the Guaíba basin, in the state of Rio Grande do Sul, were identified. Two samples were collected in summer, autumn and spring, with one replicate in each river. The total of 28,961 specimens included members of Platyhelminthes, Annelida, Acarina, Insecta, Crustacea and Mollusca. The Silveira and Marco rivers showed significant differences in the indices of Shannon-Weaver (H’, Simpson’s Reciprocal (1/D, Margalef (DMg and Equitability (E. The Silveira River showed the highest means of diversity and the EPT index (Ephemeroptera, Plecoptera, Trichoptera. Comparison among the diversity indices, considered individually, were insufficient to show differences in community structure, for the purpose of ecological characterization of the rivers. The EPT values characterized the Divisa River as having the highest abundance (73%, followed by the Marco (71%, Antas (48% and Silveira (36%. These results suggest that the Silveira River is subject to moderate environmental stress, from human impact, although it showed the highest diversity of the major macrobenthic groups.Os macro-invertebrados bentônicos que ocorrem em quatro rios, três pertencentes à bacia do Rio Pelotas (Rios Divisa, Marco e Silveira nas cabeceiras do Rio Uruguai e um ao sistema Taquari-Antas (Rio Antas, tributário da bacia do Guaíba, no Estado do Rio Grande do Sul, foram identificados. Duas amostras foram coletadas no verão, outono e primavera, com uma réplica em cada rio. Foram coletados 28961 espécimes de macro-invertebrados compreendendo Platyhelminthes, Annelida, Acarina, Insecta, Crustacea e Mollusca. Na comparação entre os rios, Silveira e Marco mostraram diferenças significativas nos índices de Shannon-Weaver (H’, no Recíproco de Simpson (1/D, de

  3. Effects of carbofuran and metsulfuron-methyl on the benthic macroinvertebrate community in flooded ricefields Efeito do carbofurano e metsulfuron-methyl sobre a comunidade de macroinvertebrados bentônicos de lavoura de arroz irrigado

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    Joele Baumart


    Full Text Available AIM: This study evaluated the effect of the insecticide carbofuran and the herbicide metsulfuron-methyl on the abundance and diversity of benthic macroinvertebrates in a paddy ricefield. METHODS: To achieve this goal, two pesticide treatments [the insecticide carbofuran (IC and the herbicide metsulfuron-methyl (HM] and a control (Co treatment with no added pesticide were established in an experimental area of the Plant Science Department of the Federal University of Santa Maria. Soil samples were collected in triplicate from each treatment 30 days before and 1, 10, and 51 days after the pesticide application, for macrofauna identification. RESULTS: Among the 21 taxa identified, Trichoceridae was present only in Co, Hydroptilidae was recorded only in IC, and Corixidae in HM. In Co, the most abundant group was Annelida, while in IC and HM Diptera (Chironomidae was dominant. Significant differences were observed between Co and IC, in the density of Odontoceridae (Control>IC and Hydrophilidae (ControlHM and Hirudinea (ControlOBJETIVO: O objetivo desse estudo foi avaliar o efeito do inseticida carbofurano e do herbicida metsulfuron-methyl na abundância e diversidade de macroinvertebrados bentônicos em campo de arroz irrigado. MÉTODOS: Para isto, dois tratamentos com agrotóxicos [o inseticida carbofurano (IC e o herbicida metsulfuron-methyl (HM] e um controle (Co, tratamento sem pesticida, foram aplicados em uma área experimental no Departamento de Fitotecnia da Universidade Federal de Santa Maria. Amostras de solo foram coletadas em triplicatas em cada tratamento 30 dias antes (DBA e 1, 10 e 51 dias após a aplicação dos pesticidas, posteriormente a macrofauna foi identificada. RESULTADOS: Vinte e um (21 taxa foram identificados, entre esses Trichoceridae esteve presente apenas em Co, enquanto que Hydroptilidae foi coletado apenas em IC, e Corixidae em HM. Em Co e IC, o grupo mais abundante foi Annelida, e em HM foi Diptera (Chironomidae que

  4. Impact of pesticides on hyphomycetes leaf processing and macroinvertebrate shredding activity

    DEFF Research Database (Denmark)

    Juul Monberg, Rikke; Rasmussen, Jes; Baatrup-Pedersen, Annette

    -cypermethrine (100, 1000 or 2000 ng/L) for three hours. Subsequently, we studied post exposure leaf degradation for four weeks in the laboratory in the presence/absence of two macroinvertebrate shredders (Gammarus pulex and Halesus radiatus) applying a classic crossed factorial design. Preliminary results indicate...... the first post exposure week when macroinvertebrate shredders were present. After four weeks no differences were apparent among treatments indicating a strong degree of functional redundancy applying this macroinvertebrate assemblage....

  5. Effect of streambed substrate on macroinvertebrate biodiversity

    Institute of Scientific and Technical Information of China (English)

    Xuehua DUAN; Zhaoyin WANG; Shimin TIAN


    Macroinvertebrates are important components of stream ecosystems, and are often used as indicator spe-cies for the assessment of river ecology. Numerous studies have shown that substrate is the primary physical envir-onmental variable affecting the taxa richness and density of macroinvertebrates. The aim of this work is to study the effects of the characteristics of streambed substrate, such as grain size, shape, and roughness, on the composition and biodiversity of macroinvertebrates. A field experi-ment was done on the Juma River, a second-order moun-tain stream in northern China. Substrata of cobbles, hewn stones, pebbles, coarse sand, and fine sand were used to replace the original gravel and sand bed in a stretch of 30 m in length. The sampling results indicated that the macroinvertebrate assemblage is significantly affected by the grain size, porosity and interstitial dimension of the substrate, while it is rarely affected by the shape and the surface roughness of the experimental substrata. Macroinvertebrate compositions in cobbles and hewn stones were stable and changed least over time. The taxa richness and density of individuals in the substrata of cobbles, hewn stones, and pebbles are much higher than in those of the coarse sand and fine sand.


    The responses of tidal marsh macroinvertebrate assemblages to the conversion of Spartina alterniflora marshes to marshes dominated by the invasive reed, Phragmites australis, are poorly understood. Changes in edaphic, vegetative, hydrological, and detrital conditions that attend ...

  7. Patterning and predicting aquatic macroinvertebrate diversities using artificial neural network

    NARCIS (Netherlands)

    Park, Y.S.; Verdonschot, P.F.M.; Chon, T.S.; Lek, S.


    A counterpropagation neural network (CPN) was applied to predict species richness (SR) and Shannon diversity index (SH) of benthic macroinvertebrate communities using 34 environmental variables. The data were collected at 664 sites at 23 different water types such as springs, streams, rivers, canals

  8. Influence of macroinvertebrate sample size on bioassessment of streams

    NARCIS (Netherlands)

    Vlek, H.E.; Sporka, F.; Krno, I.


    In order to standardise biological assessment of surface waters in Europe, a standardised method for sampling, sorting and identification of benthic macroinvertebrates in running waters was developed during the AQEM project. The AQEM method has proved to be relatively time-consuming. Hence, this stu

  9. Evaluation of alternative macroinvertebrate sampling techniques for use in a new tropical freshwater bioassessment scheme

    Directory of Open Access Journals (Sweden)

    Isabel Eleanor Moore


    Full Text Available Aim: The study aimed to determine the effectiveness of benthic macroinvertebrate dredge net sampling procedures as an alternative method to kick net sampling in tropical freshwater systems, specifically as an evaluation of sampling methods used in the Zambian Invertebrate Scoring System (ZISS river bioassessment scheme. Tropical freshwater ecosystems are sometimes dangerous or inaccessible to sampling teams using traditional kick-sampling methods, so identifying an alternative procedure that produces similar results is necessary in order to collect data from a wide variety of habitats.MethodsBoth kick and dredge nets were used to collect macroinvertebrate samples at 16 riverine sites in Zambia, ranging from backwaters and floodplain lagoons to fast flowing streams and rivers. The data were used to calculate ZISS, diversity (S: number of taxa present, and Average Score Per Taxon (ASPT scores per site, using the two sampling methods to compare their sampling effectiveness. Environmental parameters, namely pH, conductivity, underwater photosynthetically active radiation (PAR, temperature, alkalinity, flow, and altitude, were also recorded and used in statistical analysis. Invertebrate communities present at the sample sites were determined using multivariate procedures.ResultsAnalysis of the invertebrate community and environmental data suggested that the testing exercise was undertaken in four distinct macroinvertebrate community types, supporting at least two quite different macroinvertebrate assemblages, and showing significant differences in habitat conditions. Significant correlations were found for all three bioassessment score variables between results acquired using the two methods, with dredge-sampling normally producing lower scores than did the kick net procedures. Linear regression models were produced in order to correct each biological variable score collected by a dredge net to a score similar to that of one collected by kick net

  10. Climate warming and agricultural stressors interact to determine stream macroinvertebrate community dynamics. (United States)

    Piggott, Jeremy J; Townsend, Colin R; Matthaei, Christoph D


    Global climate change is likely to modify the ecological consequences of currently acting stressors, but potentially important interactions between climate warming and land-use related stressors remain largely unknown. Agriculture affects streams and rivers worldwide, including via nutrient enrichment and increased fine sediment input. We manipulated nutrients (simulating agricultural run-off) and deposited fine sediment (simulating agricultural erosion) (two levels each) and water temperature (eight levels, 0-6°C above ambient) simultaneously in 128 streamside mesocosms to determine the individual and combined effects of the three stressors on macroinvertebrate community dynamics (community composition and body size structure of benthic, drift and insect emergence assemblages). All three stressors had pervasive individual effects, but in combination often produced additive or antagonistic outcomes. Changes in benthic community composition showed a complex interplay among habitat quality (with or without sediment), resource availability (with or without nutrient enrichment) and the behavioural/physiological tendency to drift or emerge as temperature rose. The presence of sediment and raised temperature both resulted in a community of smaller organisms. Deposited fine sediment strongly increased the propensity to drift. Stressor effects were most prominent in the benthic assemblage, frequently reflected by opposite patterns in individuals quitting the benthos (in terms of their propensity to drift or emerge). Of particular importance is that community measures of stream health routinely used around the world (taxon richness, EPT richness and diversity) all showed complex three-way interactions, with either a consistently stronger temperature response or a reversal of its direction when one or both agricultural stressors were also in operation. The negative effects of added fine sediment, which were often stronger at raised temperatures, suggest that streams already

  11. Zoogeografía de macroinvertebrados bentónicos de la costa de Chile: contribución para la conservación marina Zoogeography of benthic macroinvertebrates of the Chilean coast: contribution for marine conservation

    Directory of Open Access Journals (Sweden)



    Full Text Available La diversidad de macroinvertebrados marinos ha recibido una atención creciente, no obstante, con un escaso tratamiento en el contexto biogeográfico. Este estudio analiza los registros de 1.601 especies de macroinvertebrados bentónicos pertenecientes a: Demospongiae, Anthozoa, Polychaeta, Mollusca, Crustacea, Echinodermata y Ascideacea, agrupados en 10 zonas y tratados desde una perspectiva zoogeográfica. Mollusca (611 especies, Polychaeta (403 y Crustacea (370 corresponden a los grupos mejor representados a lo largo de la costa chilena, determinantes en el patrón global de la biodiversidad. Este aumenta suavemente de norte a sur, interrumpido por máximos que sugieren esfuerzos diferenciales de estudio más que un comportamiento natural de la biodiversidad. El grado de agrupamiento entre las zonas muestra las tres unidades biogeográficas definidas recientemente por Lancellotti & Vásquez. Este arreglo, que representa lo exhibido por los grupos más diversos, se ve alterado en los grupos menos representados donde las diferencias obedecen al patrón de afinidades mostradas por las zonas comprendidas dentro de la Región Templada Transicional. El quiebre zoogeográfico alrededor de los 41º S, sugerido largamente en la literatura, sólo ocurre en Echinodermata y Demospongiae, evidenciando en los otros taxa la existencia de un área de transición entre los 35º y 48º S, caracterizada por un reemplazo gradual de especies. Dentro de las regiones la biodiversidad muestra homogeneidad, contrario al endemismo, el que alcanza un máximo de 52% en la Región Templada Fría y que parece ser consecuencia del alto número de especies con registros únicos (38,2% de especies citadas para una sóla zona. Esto sugiere un desconocimiento de los macroinvertebrados chilenos (distribución y diversidad, sobrestimando el endemismo regional y distorsionando los patrones locales de biodiversidadThe diversity of marine macroinvertebrates has received increasing

  12. Comparison of two methods for estimating the abundance, diversity and habitat preference of fluvial macroinvertebrates in contrasting habitats

    NARCIS (Netherlands)

    Alonso, A.; Camargo, J.A.


    In this research we evaluate the effects of the method used for estimating the potential surface available for benthic macroinvertebrates in macrophyte and unvegetated habitats on several metrics and habitat preference of aquatic macroinvertebrates in the upper catchment of the Henares River (Guadal

  13. Comparison of macroinvertebrate-derived stream quality metrics between snag and riffle habitats (United States)

    Stepenuck, K.F.; Crunkilton, R.L.; Bozek, Michael A.; Wang, L.


    We compared benthic macroinvertebrate assemblage structure at snag and riffle habitats in 43 Wisconsin streams across a range of watershed urbanization using a variety of stream quality metrics. Discriminant analysis indicated that dominant taxa at riffles and snags differed; Hydropsychid caddisflies (Hydropsyche betteni and Cheumatopsyche spp.) and elmid beetles (Optioservus spp. and Stenemlis spp.) typified riffles, whereas isopods (Asellus intermedius) and amphipods (Hyalella azteca and Gammarus pseudolimnaeus) predominated in snags. Analysis of covariance indicated that samples from snag and riffle habitats differed significantly in their response to the urbanization gradient for the Hilsenhoff biotic index (BI), Shannon's diversity index, and percent of filterers, shredders, and pollution intolerant Ephemeroptera, Plecoptera, and Trichoptera (EPT) at each stream site (p ??? 0.10). These differences suggest that although macroinvertebrate assemblages present in either habitat type are sensitive to detecting the effects of urbanization, metrics derived from different habitats should not be intermixed when assessing stream quality through biomonitoring. This can be a limitation to resource managers who wish to compare water quality among streams where the same habitat type is not available at all stream locations, or where a specific habitat type (i.e., a riffle) is required to determine a metric value (i.e., BI). To account for differences in stream quality at sites lacking riffle habitat, snag-derived metric values can be adjusted based on those obtained from riffles that have been exposed to the same level of urbanization. Comparison of nonlinear regression equations that related stream quality metric values from the two habitat types to percent watershed urbanization indicated that snag habitats had on average 30.2 fewer percent EPT individuals, a lower diversity index value than riffles, and a BI value of 0.29 greater than riffles. ?? 2008 American Water

  14. Penicillin-mediated changes in viable benthic diatom assemblages – insights about the relevance of bacteria across spatial and seasonal scales.

    Digital Repository Service at National Institute of Oceanography (India)

    DeCosta, P.M.; Anil, A.C.

    environment) and seasonal (post-monsoon, pre-monsoon, monsoon) scales. Penicillin treatment resulted in bacterial suppression and a reduction in diatoms at the intertidal and mangrove sites having stable pennate-dominated assemblages. Diatom response...

  15. The Relative Influence of Catchment and Site Variabbles on Fish and Macroinvertebrate Richness in Cerrado Biome Streams (United States)

    Landscape and site-scale data aid the interpretation of biological data and management alternatives. We evaluated how three classes of environmental variables (natural landscape, anthropogenic pressures, and local physical habitat), influence fish and macroinvertebrate assemblage...

  16. Deforestation and benthic indicators: how much vegetation cover is needed to sustain healthy Andean streams? (United States)

    Iñiguez-Armijos, Carlos; Leiva, Adrián; Frede, Hans-Georg; Hampel, Henrietta; Breuer, Lutz


    Deforestation in the tropical Andes is affecting ecological conditions of streams, and determination of how much forest should be retained is a pressing task for conservation, restoration and management strategies. We calculated and analyzed eight benthic metrics (structural, compositional and water quality indices) and a physical-chemical composite index with gradients of vegetation cover to assess the effects of deforestation on macroinvertebrate communities and water quality of 23 streams in southern Ecuadorian Andes. Using a geographical information system (GIS), we quantified vegetation cover at three spatial scales: the entire catchment, the riparian buffer of 30 m width extending the entire stream length, and the local scale defined for a stream reach of 100 m in length and similar buffer width. Macroinvertebrate and water quality metrics had the strongest relationships with vegetation cover at catchment and riparian scales, while vegetation cover did not show any association with the macroinvertebrate metrics at local scale. At catchment scale, the water quality metrics indicate that ecological condition of Andean streams is good when vegetation cover is over 70%. Further, macroinvertebrate community assemblages were more diverse and related in catchments largely covered by native vegetation (>70%). Our results suggest that retaining an important quantity of native vegetation cover within the catchments and a linkage between headwater and riparian forests help to maintain and improve stream biodiversity and water quality in Andean streams affected by deforestation. This research proposes that a strong regulation focused to the management of riparian buffers can be successful when decision making is addressed to conservation/restoration of Andean catchments.

  17. Deforestation and benthic indicators: how much vegetation cover is needed to sustain healthy Andean streams?

    Directory of Open Access Journals (Sweden)

    Carlos Iñiguez-Armijos

    Full Text Available Deforestation in the tropical Andes is affecting ecological conditions of streams, and determination of how much forest should be retained is a pressing task for conservation, restoration and management strategies. We calculated and analyzed eight benthic metrics (structural, compositional and water quality indices and a physical-chemical composite index with gradients of vegetation cover to assess the effects of deforestation on macroinvertebrate communities and water quality of 23 streams in southern Ecuadorian Andes. Using a geographical information system (GIS, we quantified vegetation cover at three spatial scales: the entire catchment, the riparian buffer of 30 m width extending the entire stream length, and the local scale defined for a stream reach of 100 m in length and similar buffer width. Macroinvertebrate and water quality metrics had the strongest relationships with vegetation cover at catchment and riparian scales, while vegetation cover did not show any association with the macroinvertebrate metrics at local scale. At catchment scale, the water quality metrics indicate that ecological condition of Andean streams is good when vegetation cover is over 70%. Further, macroinvertebrate community assemblages were more diverse and related in catchments largely covered by native vegetation (>70%. Our results suggest that retaining an important quantity of native vegetation cover within the catchments and a linkage between headwater and riparian forests help to maintain and improve stream biodiversity and water quality in Andean streams affected by deforestation. This research proposes that a strong regulation focused to the management of riparian buffers can be successful when decision making is addressed to conservation/restoration of Andean catchments.


    Directory of Open Access Journals (Sweden)

    Joseline Molozzi


    Full Text Available Rice is one of the main cereals grown in Brazil. The handling of the rice culture may impact in the river downstream of the farming. The main goal of this research was to evaluate the distribution and occurrence of benthic macroinvertebrates in rivers with rice plantations. This research was developed in the cities of Gaspar and Agrolândia, in Itajaí River Basin, Santa Catarina, Brazil. In Gaspar City, macroinvertebrate data and environmental information were collected quarterly, in August/04, November/04 and February/05. In Agrolândia City, they were also collected quarterly in October/04, January/05 and April/05. Benthic macroinvertebrates samples were collected using Surber sampler. The macroinvertebrates were identified at family level. Diversity was estimated using Shannon, Margalef and Evenness Indices. To compare the diversity among these sites, T Student Test was used. Richness and Dominance were also determinated. 21.831 organisms were collected at the six sites. 73% were Diptera with predominance of Chironomidae family with 14.956 individuals. Site 4 had the lowest diversity and the highest dominance. In rivers under influence of the rice culture it is observed predominance of taxons resistant to pollution. Taxons more sensitive to pollution were hardly found at the six sites, demonstrating the inappropriate conditions for their development. = O arroz é um dos principais cereais cultivados no Brasil. No manejo desta cultura é possível que ocorra um impacto no corpo hídrico à jusante das lavouras. Este trabalho teve por objetivo estudar a distribuição e ocorrência de macroinvertebrados bentônicos em rios nas áreas com cultura orizícola. O estudo foi desenvolvido nos municípios de Gaspar e Agrolândia, localizados na bacia do Itajaí, SC. As coletas foram realizadas trimestralmente, em agosto e novembro de 2004 e fevereiro de 2005 em Gaspar, outubro de 2004, janeiro e abril de 2005 em Agrolândia. As amostras de

  19. Categorização funcional trófica das comunidades de macroinvertebrados de dois reservatórios na região Centro-Oeste do Estado de São Paulo, Brasil - DOI: 10.4025/actascibiolsci.v31i1.331 Functional feeding groups of benthics macroinvertebrates communities of two lentic systems in the central west region of São Paulo State - DOI: 10.4025/actascibiolsci.v31i1.331

    Directory of Open Access Journals (Sweden)

    Jandira Liria Biscalquini Talamoni


    Full Text Available A utilização do conceito de guilda pode ser útil para a categorização funcional trófica de comunidades, pois não há obrigatoriedade da identificação dos organismos em nível de espécie, nem de tratar cada espécie como uma entidade separada. O objetivo deste estudo foi analisar os grupos funcionais tróficos (coletores-catadores, coletores-filtradores, fragmentadores, predadores e raspadores das comunidades de macroinvertebrados de dois reservatórios da região Centro-Oeste do Estado de São Paulo, Brasil. As amostragens foram realizadas nos períodos chuvoso (março/abril - 2001 e de seca (julho/agosto - 2001 e os dados obtidos indicam que os coletores-catadores foram a guilda mais frequente. Este fato sugere grande importância da matéria orgânica como recurso alimentar na dieta dos macroinvertebrados analisados.The aim of this study was analyze the functional feeding groups (collectors, shredders, predators and grazer-scrapers of benthic macroinvertebrates communities in two lentic systems in the central west region of São Paulo State. The samples were realized in rainy (March/April - 2001 and dry (July/August - 2001 seasons. The results obtained contribute for the best knowledgement of benthic macroinvertebrate community on those two systems.

  20. 引水式小水电对重庆东河大型底栖动物多样性的影响%Impacts of small diversion type hydropower station on benthic macroinvertebrates biodiversity in Dong River in Chongqing

    Institute of Scientific and Technical Information of China (English)

    王强; 袁兴中; 刘红; 张耀光; 王志坚


    为研究引水式小水电对山区河流底栖动物群落结构及多样性的影响,2011年6月对重庆东河白里电站和红花电站库尾上游河段、库区河段、引水坝下减水河段、电站出水口上游河段、电站出水口下游河段的底栖动物进行调查。调查共采集到大型底栖动物43种,隶属3门4纲30科。结果表明:各河段底栖动物群落结构差异不大,蜉蝣目、毛翅目昆虫为优势类群,各河段水质并无明显差异;库区河段受泥沙淤积影响,降低了生境多样性和异质性,底栖动物密度、生物量和多样性指数显著低于电站出水口下游河段;坝下河段流量减少,生境适宜性降低,底栖动物密度、生物量和多样性明显降低。%In order to explore the influence of small diversion type hydropower stations on macroinvertebrates community and diversity, macroinvertebrates of five river reaches ( upstream of reservoir , reservoir, downstream of the dam and downstream of the station ) of Baili and Honghua stations on Dong River located in Chongqing , China were investigated in June of 2011 .Our results indicated that forty-three species were collected in the survey , subordinating to thirty families , four classes and three phylums .The influences of two small diversion type hydropower stations on macroinvertebrates were not obvious and Ephemeroptera or Trichoptera were still the dominant taxon in all the sampled river reaches .As a conse-quence of sediment deposition , water depth of the reservoir was shallow and its flow pattern was still lotic , which was quite different from that of large dams .Component of macroinvertebrate community in the reservoir was not significantly different from the reaches unaffected by the dam , but the density , biodiversity and biomass were significantly depressed as a result of the loss of habitat diversity and heterogeneity .Mean water width, depth, speed and discharge of the reach in the down

  1. Prey distribution, physical habitat features, and guild traits interact to produce contrasting shorebird assemblages among foraging patches.

    Directory of Open Access Journals (Sweden)

    Beth M VanDusen

    Full Text Available Worldwide declines in shorebird populations, driven largely by habitat loss and degradation, motivate environmental managers to preserve and restore the critical coastal habitats on which these birds depend. Effective habitat management requires an understanding of the factors that determine habitat use and value to shorebirds, extending from individuals to the entire community. While investigating the factors that influenced shorebird foraging distributions among neighboring intertidal sand flats, we built upon species-level understandings of individual-based, small-scale foraging decisions to develop more comprehensive guild- and community-level insights. We found that densities and community composition of foraging shorebirds varied substantially among elevations within some tidal flats and among five flats despite their proximity (all located within a 400-m stretch of natural, unmodified inlet shoreline. Non-dimensional multivariate analyses revealed that the changing composition of the shorebird community among flats and tidal elevations correlated significantly (ρ(s = 0.56 with the spatial structure of the benthic invertebrate prey community. Sediment grain-sizes affected shorebird community spatial patterns indirectly by influencing benthic macroinvertebrate community compositions. Furthermore, combining sediment and macroinvertebrate information produced a 27% increase in correlation (ρ(s = 0.71 with shorebird assemblage patterns over the correlation of the bird community with the macroinvertebrate community alone. Beyond its indirect effects acting through prey distributions, granulometry of the flats influenced shorebird foraging directly by modifying prey availability. Our study highlights the importance of habitat heterogeneity, showing that no single patch type was ideal for the entire shorebird community. Generally, shorebird density and diversity were greatest at lower elevations on flats when they became exposed; these

  2. Comparison of live and dead molluscan assemblages suggests recent human-driven decline in benthic diversity in Phetchaburi (NW Gulf of Thailand) (United States)

    Negri, Mauro Pietro; Sanfilippo, Rossana; Basso, Daniela; Rosso, Antonietta


    Dead and live molluscan assemblages from the coastal area of Phetchaburi (NW Gulf of Thailand) were compared by means of multivariate analysis. Seven thanatofacies were recognized, thriving in the area after the 1960s. Five of them, scattered along the tidal flat, represent oligotypic intertidal biotopes linked to a variety of environmental factors; the remaining two mirror high-diversity infralittoral associations. Conversely, only two poor, ill-defined biofacies thrive at present between the intertidal and the shallow infralittoral zones, somewhat resembling two of the thanatofacies. Diversity indexes reveal a dramatic biodiversity decline occurred from the 1960s onwards, far beyond the effects of time-averaging and accumulation. The responsibility for this reduction is largely attributable to the high impact of human activities, such as the intensive sea bottom trawling, the wastewaters from aquaculture (shrimp and fish ponds) and dense coastal villages, and, at a minor extent, the digging of edible molluscs from the tidal flat.

  3. Benthic Assemblages of the Anton Dohrn Seamount (NE Atlantic): Defining Deep-Sea Biotopes to Support Habitat Mapping and Management Efforts with a Focus on Vulnerable Marine Ecosystems. (United States)

    Davies, Jaime S; Stewart, Heather A; Narayanaswamy, Bhavani E; Jacobs, Colin; Spicer, John; Golding, Neil; Howell, Kerry L


    In 2009 the NW and SE flanks of Anton Dohrn Seamount were surveyed using multibeam echosounder and video ground-truthing to characterise megabenthic biological assemblages (biotopes) and assess those which clearly adhere to the definition of Vulnerable Marine Ecosystems, for use in habitat mapping. A combination of multivariate analysis of still imagery and video ground-truthing defined 13 comprehensive descriptions of biotopes that function as mapping units in an applied context. The data reveals that the NW and SE sides of Anton Dohrn Seamount (ADS) are topographically complex and harbour diverse biological assemblages, some of which agree with current definitions of 'listed' habitats of conservation concern. Ten of these biotopes could easily be considered Vulnerable Marine Ecosystems; three coral gardens, four cold-water coral reefs, two xenophyophore communities and one sponge dominated community, with remaining biotopes requiring more detailed assessment. Coral gardens were only found on positive geomorphic features, namely parasitic cones and radial ridges, found both sides of the seamount over a depth of 1311-1740 m. Two cold-water coral reefs (equivalent to summit reef) were mapped on the NW side of the seamount; Lophelia pertusa reef associated with the cliff top mounds at a depth of 747-791 m and Solenosmilia variabilis reef on a radial ridge at a depth of 1318-1351 m. Xenophyophore communities were mapped from both sides of the seamount at a depth of 1099-1770 m and were either associated with geomorphic features or were in close proximity (< 100 m) to them. The sponge dominated community was found on the steep escarpment either side of the seamount over at a depth of 854-1345 m. Multivariate diversity revealed the xenophyophore biotopes to be the least diverse, and a hard substratum biotope characterised by serpulids and the sessile holothurian, Psolus squamatus, as the most diverse.

  4. Benthic Assemblages of the Anton Dohrn Seamount (NE Atlantic: Defining Deep-Sea Biotopes to Support Habitat Mapping and Management Efforts with a Focus on Vulnerable Marine Ecosystems.

    Directory of Open Access Journals (Sweden)

    Jaime S Davies

    Full Text Available In 2009 the NW and SE flanks of Anton Dohrn Seamount were surveyed using multibeam echosounder and video ground-truthing to characterise megabenthic biological assemblages (biotopes and assess those which clearly adhere to the definition of Vulnerable Marine Ecosystems, for use in habitat mapping. A combination of multivariate analysis of still imagery and video ground-truthing defined 13 comprehensive descriptions of biotopes that function as mapping units in an applied context. The data reveals that the NW and SE sides of Anton Dohrn Seamount (ADS are topographically complex and harbour diverse biological assemblages, some of which agree with current definitions of 'listed' habitats of conservation concern. Ten of these biotopes could easily be considered Vulnerable Marine Ecosystems; three coral gardens, four cold-water coral reefs, two xenophyophore communities and one sponge dominated community, with remaining biotopes requiring more detailed assessment. Coral gardens were only found on positive geomorphic features, namely parasitic cones and radial ridges, found both sides of the seamount over a depth of 1311-1740 m. Two cold-water coral reefs (equivalent to summit reef were mapped on the NW side of the seamount; Lophelia pertusa reef associated with the cliff top mounds at a depth of 747-791 m and Solenosmilia variabilis reef on a radial ridge at a depth of 1318-1351 m. Xenophyophore communities were mapped from both sides of the seamount at a depth of 1099-1770 m and were either associated with geomorphic features or were in close proximity (< 100 m to them. The sponge dominated community was found on the steep escarpment either side of the seamount over at a depth of 854-1345 m. Multivariate diversity revealed the xenophyophore biotopes to be the least diverse, and a hard substratum biotope characterised by serpulids and the sessile holothurian, Psolus squamatus, as the most diverse.

  5. Functional diversity of macrobenthic assemblages decreases in response to sewage discharges

    NARCIS (Netherlands)

    Gusmao, Joao B.; Brauko, Kalina M.; Eriksson, Britas K.; Lana, Paulo C.


    We analyzed the effects of sewage discharge on a subtropical estuary by comparing the functional diversity of intertidal macroinvertebrate assemblages in contaminated with non-contaminated reference areas. Functional structure was assessed using biological traits analysis (BTA) and four multivariate

  6. Effect of Ocean Acidification and pH Fluctuations on the Growth and Development of Coralline Algal Recruits, and an Associated Benthic Algal Assemblage.

    Directory of Open Access Journals (Sweden)

    Michael Y Roleda

    Full Text Available Coralline algae are susceptible to the changes in the seawater carbonate system associated with ocean acidification (OA. However, the coastal environments in which corallines grow are subject to large daily pH fluctuations which may affect their responses to OA. Here, we followed the growth and development of the juvenile coralline alga Arthrocardia corymbosa, which had recruited into experimental conditions during a prior experiment, using a novel OA laboratory culture system to simulate the pH fluctuations observed within a kelp forest. Microscopic life history stages are considered more susceptible to environmental stress than adult stages; we compared the responses of newly recruited A. corymbosa to static and fluctuating seawater pH with those of their field-collected parents. Recruits were cultivated for 16 weeks under static pH 8.05 and 7.65, representing ambient and 4× preindustrial pCO2 concentrations, respectively, and two fluctuating pH treatments of daily [Formula: see text] (daytime pH = 8.45, night-time pH = 7.65 and daily [Formula: see text] (daytime pH = 8.05, night-time pH = 7.25. Positive growth rates of new recruits were recorded in all treatments, and were highest under static pH 8.05 and lowest under fluctuating pH 7.65. This pattern was similar to the adults' response, except that adults had zero growth under fluctuating pH 7.65. The % dry weight of MgCO3 in calcite of the juveniles was reduced from 10% at pH 8.05 to 8% at pH 7.65, but there was no effect of pH fluctuation. A wide range of fleshy macroalgae and at least 6 species of benthic diatoms recruited across all experimental treatments, from cryptic spores associated with the adult A. corymbosa. There was no effect of experimental treatment on the growth of the benthic diatoms. On the community level, pH-sensitive species may survive lower pH in the presence of diatoms and fleshy macroalgae, whose high metabolic activity may raise the pH of the local microhabitat.

  7. Effect of Ocean Acidification and pH Fluctuations on the Growth and Development of Coralline Algal Recruits, and an Associated Benthic Algal Assemblage. (United States)

    Roleda, Michael Y; Cornwall, Christopher E; Feng, Yuanyuan; McGraw, Christina M; Smith, Abigail M; Hurd, Catriona L


    Coralline algae are susceptible to the changes in the seawater carbonate system associated with ocean acidification (OA). However, the coastal environments in which corallines grow are subject to large daily pH fluctuations which may affect their responses to OA. Here, we followed the growth and development of the juvenile coralline alga Arthrocardia corymbosa, which had recruited into experimental conditions during a prior experiment, using a novel OA laboratory culture system to simulate the pH fluctuations observed within a kelp forest. Microscopic life history stages are considered more susceptible to environmental stress than adult stages; we compared the responses of newly recruited A. corymbosa to static and fluctuating seawater pH with those of their field-collected parents. Recruits were cultivated for 16 weeks under static pH 8.05 and 7.65, representing ambient and 4× preindustrial pCO2 concentrations, respectively, and two fluctuating pH treatments of daily [Formula: see text] (daytime pH = 8.45, night-time pH = 7.65) and daily [Formula: see text] (daytime pH = 8.05, night-time pH = 7.25). Positive growth rates of new recruits were recorded in all treatments, and were highest under static pH 8.05 and lowest under fluctuating pH 7.65. This pattern was similar to the adults' response, except that adults had zero growth under fluctuating pH 7.65. The % dry weight of MgCO3 in calcite of the juveniles was reduced from 10% at pH 8.05 to 8% at pH 7.65, but there was no effect of pH fluctuation. A wide range of fleshy macroalgae and at least 6 species of benthic diatoms recruited across all experimental treatments, from cryptic spores associated with the adult A. corymbosa. There was no effect of experimental treatment on the growth of the benthic diatoms. On the community level, pH-sensitive species may survive lower pH in the presence of diatoms and fleshy macroalgae, whose high metabolic activity may raise the pH of the local microhabitat.

  8. Macroinvertebrate distribution and aquatic ecology in the Ruoergai (Zoige) Wetland, the Yellow River source region (United States)

    Zhao, Na; Xu, Mengzhen; Li, Zhiwei; Wang, Zhaoyin; Zhou, Hanmi


    The Ruoergai (Zoige) Wetland, the largest plateau peatland in the world, is located in the Yellow River source region. The discharge of the Yellow River increases greatly after flowing through the Ruoergai Wetland. The aquatic ecosystem of the Ruoergai Wetland is crucial to the whole Yellow River basin. The Ruoergai wetland has three main kinds of water bodies: rivers, oxbow lakes, and marsh wetlands. In this study, macroinvertebrates were used as indicators to assess the aquatic ecological status because their assemblage structures indicate long-term changes in environments with high sensitivity. Field investigations were conducted in July, 2012 and in July, 2013. A total of 72 taxa of macroinvertebrates belonging to 35 families and 67 genera were sampled and identified. Insecta was the dominant group in the Ruoergai Basin. The alpha diversity of macroinvertebrates at any single sampling site was low, while the alpha diversity on a basin-wide scale was much higher. Macroinvertebrate assemblages in rivers, oxbow lakes, and marsh wetlands differ markedly. Hydrological connectivity was a primary factor causing the variance of the bio-community. The river channels had the highest alpha diversity of macroinvertebrates, followed by marsh wetlands and oxbow lakes. The density and biomass of Gastropoda, collector filterers, and scrapers increased from rivers to oxbow lakes and then to marsh wetlands. The river ecology was particular in the Ruoergai Wetland with the high beta diversity of macroinvertebrates, the low alpha diversity of macroinvertebrates, and the low taxa richness, density, and biomass of EPT (Ephemeroptera, Plecoptera, Trichoptera). To maintain high alpha diversity of macroinvertebrates macroinvertebrates in the Ruoergai Wetland, moderate connectivity of oxbow lakes and marsh wetlands with rivers and measures to control headwater erosion are both crucial.

  9. Surface flow types, near-bed hydraulics and the distribution of stream macroinvertebrates

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    M. A. Reid


    Full Text Available Spatial variation in hydraulic conditions in streams often results in distinct water surface patterns, or surface flow types. Visual assessments of the distribution of surface flow types have been used to provide rapid assessment of the habitat heterogeneity. The efficacy of this approach is predicated on the notion that surface flow types consistently represent a distinct suite of hydraulic conditions with biological relevance. This study tested this notion, asking three specific questions. First, do surface flow types provide a characterisation of physical habitat that is relevant to macroinvertebrates? Second, how well do near-bed hydraulic conditions explain macroinvertebrate distributions? Third, what components of near-bed hydraulic conditions exert the strongest influence on macroinvertebrate distributions?

    Results show that hydraulic conditions (incorporating direct measurements of near-bed velocity and turbulence in three dimensions and substratum character (incorporating estimates of particle size distribution, and biofilm and macrophyte cover within each surface flow type were largely distinct and that macroinvertebrate assemblages differed across flow types in taxon richness and assemblage composition, thus supporting the notion that rapid assessments of surface flow type distributions provide biologically relevant information.

    Macroinvertebrate assemblages were most strongly correlated with water depth, size of a flow type patch, near-bed velocity in the downstream direction, turbulence in the transverse direction, % pebble, % sand, % silt and clay and macrophyte cover. This study suggests that surface flow type mapping provides an assessment of physical habitat that is relevant to macroinvertebrates. The strong relationship detected between macroinvertebrate assemblages and transverse turbulence also highlights the value of directly measuring near-bed hydraulics. Further investigations are required to test the

  10. Surface flow types, near-bed hydraulics and the distribution of stream macroinvertebrates

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    M. A. Reid


    Full Text Available Spatial variation in hydraulic conditions in streams often results in distinct water surface patterns, or surface flow types. Visual assessments of the distribution of surface flow types have been used to provide rapid assessment of habitat heterogeneity. The efficacy of this approach is predicated on the notion that surface flow types consistently represent a distinct suite of hydraulic conditions with biological relevance. This study tested this notion, asking three specific questions. First, do surface flow types provide a characterisation of physical habitat that is relevant to macroinvertebrates? Second, how well do near-bed hydraulic conditions explain macroinvertebrate distributions? Third, what components of near-bed hydraulic conditions exert the strongest influence on macroinvertebrate distributions?

    Results show that hydraulic conditions (incorporating direct measurements of near-bed velocity and turbulence in three dimensions and substratum character (incorporating estimates of particle size distribution, and biofilm and macrophyte cover within each surface flow type were largely distinct and that macroinvertebrate assemblages differed across flow types in taxon richness and assemblage composition, thus supporting the notion that rapid assessments of surface flow type distributions provide biologically relevant information.

    Macroinvertebrate assemblages were most strongly correlated with water depth, size of a flow type patch, near-bed velocity in the downstream direction, turbulence in the transverse direction, % pebble, % sand, % silt and clay and macrophyte cover. This study suggests that surface flow type mapping provides an assessment of physical habitat that is relevant to macroinvertebrates. The strong relationship detected between macroinvertebrate assemblages and transverse turbulence also highlights the value of directly measuring near-bed hydraulics. Further investigations are required to test the

  11. Contrasting responses of coral reef fauna and foraminiferal assemblages to human influence in La Parguera, Puerto Rico (United States)

    Coral reef biota including stony corals, sponges, gorgonians, fish, benthic macroinvertebrates and foraminifera were surveyed in coastal waters near La Parguera, in southwestern Puerto Rico. The goal was to evaluate sensitivity of coral reef biological indicators to human distur...

  12. The response of benthic foraminifer, ostracod and mollusc assemblages to environmental conditions: a case study from the Camalti Saltpan (Izmir-Western Turkey

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    E. MERIC


    Full Text Available The subject of this report is benthic foraminifer populations preserved in the saltpan of Camalti in the Province of Izmir. High salinity in certain habitats of Ammonia tepida Cushman may be the primary cause of the high rate of twins and triplets as well as other morphological abnormalities recorded within this species (50 % as compared to an anomaly rate of 1 % in normal marine waters. Thicker cyst membrane developing in extremely saline environments may encourage twins and other morphological deformities by denying free movement of the offspring. Ecological factors such as heavy metal contamination of ambient waters as well as contamination by other wastes are also not ruled out as leading to such developmental anomalies. Of the 27 collected samples, Number 5 (that is closest to the sea includes the typical marine foraminifers. Nonion depressulum (Walker & Jacob, Ammonia tepida Cushman and Porosononion subgronosum(Egger are the dominant species in other samples. A total of 63 abnormal individuals (8 triplets, 24 twins, and 31 morphological anomalies was found within seven of the 27 samples collected. Ten samples contained freshwater ostracods: Darwinula stevensoni(Brady and Robertson, Leptocythere lacertosa Hirschmann, Cyprideis torasa (Jones, Cyprideis (C. anatolica Bassiouni, and Loxochoncha elliptica Brady. Among these samples (some of which contained only a few species of ostracods - and those limited in number of offspring, one had an unusually high ratio of healthy foraminifers vs those with anomalies. Worthy of note in another sample was a high abundance of molluscs. Among pelecypods, were found Ostrea edulis Linné, Lucinella divaricata (Linné, Pseudocama gryphina Lamarck,Cerastoderma edule (Linné, and Scrobicularia plana da Costa; and among gastropods were identified Hydrobi (Hydrobia acuta(Draparnaud, Rissoa labiosa (Montagu, R. parva (da Costa, R. violacea Desmarest, Pirenella conica (Blainville, Bittium desayesi(Cerulli and

  13. Effects of cutting disturbance in Schoenoplectus californicus (C.A. Mey. Soják on the benthic macroinvertebrates = Efeito do distúrbio de corte em Schoenoplectus californicus (C.A. Mey. Soják sobre a fauna de macroinvertebrados bentônicos

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    Thiago Cesar Lima Silveira


    Full Text Available Lagoons are considered protected areas because these systems play a key ecological role. However, the extraction of macrophyte Schoenoplectus californicus is held for manufacture of handcrafts, being an alternative income for riverbank communities. This studyevaluated the impact of S. californicus experimental cutting on benthic macroinvertebrates trough a field experiment. Macroinvertebrates were sampled at 1, 12, 26 and 60 days after themacrophyte cutting in demarked plots (1 m², as well at control plots. The families number was not statistically different (ANOVA, p > 0.05, but the total density of invertebrates, and the density of Ceratopogonidae were significant (ANOVA, p No Brasil, as margens de lagoas são consideradas áreas protegidas por desempenharem importante papel ecológico. No entanto, a extração da macrófita Schoenoplectus californicus é realizada para a fabricação de artesanato, sendo alternativa de renda para as comunidades ribeirrinhas. Este estudo teve como objetivo avaliar o impacto do corte de S. californicus sobre os macroinvertebrados bentônicos por meio de um experimento de campo. Os macroinvertebrados foram amostrados um dia, 12, 26 e 60 dias após o corte em macrófitas em parcelas demarcadas (1 m², bem como nas parcelas-controle. As famílias de macroinvertebrados mais abundantes não apresentaram diferenças significativas (ANOVA, p < 0,05, mas a densidade total de invertebrados e a densidade de Ceratopogonidae foram significativas (ANOVA, p < 0,05 para a interação entre a data de amostragem e tratamento. A Análise de Componentes Principais identificou que a profundidade no local do experimento foi a variável que influenciou a variabilidade entre as amostras coletadas no experimento. Concluiu-seque o corte de S. californicus, nessa área, como a intensidade do corte realizado, não afeta drasticamente a composição de macroinvertebrados aquáticos. Os resultados sugerem que o extrativismo em pequenas

  14. Marine sediment sample pre-processing for macroinvertebrates metabarcoding: mechanical enrichment and homogenization

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    Eva Aylagas


    Full Text Available Metabarcoding is an accurate and cost-effective technique that allows for simultaneous taxonomic identification of multiple environmental samples. Application of this technique to marine benthic macroinvertebrate biodiversity assessment for biomonitoring purposes requires standardization of laboratory and data analysis procedures. In this context, protocols for creation and sequencing of amplicon libraries and their related bioinformatics analysis have been recently published. However, a standardized protocol describing all previous steps (i.e. processing and manipulation of environmental samples for macroinvertebrate community characterization is lacking. Here, we provide detailed procedures for benthic environmental sample collection, processing, enrichment for macroinvertebrates, homogenization, and subsequent DNA extraction for metabarcoding analysis. Since this is the first protocol of this kind, it should be of use to any researcher in this field, having the potential for improvement.

  15. 阿什河珍珠梅树叶的分解速率与大型底栖动物定殖关系1)%Relationship between Decomposition Rates of Sorbaria sorbifolia and Colonization Benthic Macroinvertebrate in the Stream of Ashihe River

    Institute of Scientific and Technical Information of China (English)

    董雪; 刘曼红; 于洪贤


    利用复合分解网袋(上半部为1.0 mm孔径,下半部为0.5 mm孔径)在阿什河上游森林段、中上游农田段和阿什河入松花江口城市段放入珍珠梅树叶,并对其进行了为期77 d的树叶分解研究。结果表明:森林段、农田段和城市段树叶分解速率都为0.02,符合指数衰减模型,均属于快速分解组。不同的河段定殖的底栖动物种类数明显不同,定殖在森林段和农田段大型底栖动物种类分别为25种和15种,二者均以双翅目摇蚊幼虫为主,分别占大型底栖动物类群数的83.6%和70.5%。城市段大型底栖动物种类为6种,全部为寡毛类。从大型底栖动物摄食功能群比例看,森林河段珍珠梅树叶上的大型底栖动物主要以直接集食者为主,占43.7%;其次是撕食者(39.3%)和捕食者(14.4%)。农田河段珍珠梅树叶上大型底栖动物直接集食者比例最高,为77.27%;其次是撕食者为(13.63%)和过滤收集者(4.54%)。城市河段珍珠梅树叶上大型底栖动物全部为直接集食者。结果表明,阿什河上游、中上游和下游中直接集食的底栖动物丰富度与树叶分解速率有显著关系。%The experiment was conducted to study the leaves decomposition rates of Sorbaria sorbifolia with decomposition bags (upper half’s diameter is 1 mm and another half’s diameter is 0.5 mm ) for 77 days in the forest section at the upper rea-ches of the Ashihe River , upstream farmland section and the city section of the River into the Songhua River .The leaf de-composition rates of the forest section , the farmland section and the city section were both 0.02, and the decomposition rate accorded with exponential decay model .Leaves of those sections belonged to the rapid decomposition groups .In the whole experiment process , the species numbers colonization benthic macroinvertebrate of the three sections was obviously

  16. Influence of environmental factors on benthic macroinvertebrate communities of urban streams in Vereda habitats, Central Brazil Influência de variáveis ambientais na comunidade de macroinvertebrados bentônicos de córregos urbanos de Veredas, Brasil Central

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    Renata de Moura Guimaraes Souto


    Full Text Available AIM: Veredas and the aquatic and semi-aquatic communities play a key role in watershed protection in the Cerrado Biome. Information about the effects of physical and chemical variables and habitat integrity on benthic communities has been increased in recent years; however, there is no study evaluating the influence of urbanization on macroinvertebrates of Vereda streams. Thus, improving the knowledge of the relationship between abiotic properties and benthic fauna is very important for understanding the functioning of ecological processes and health of aquatic ecosystems. This study investigated the influence of physical and chemical variables on benthic macroinvertebrate communities along a gradient of anthropogenic disturbance in four Vereda streams in Uberlândia (MG, one in a preserved area and three in the urban area; METHODS: samplings were collected during the dry and rainy seasons; RESULTS: principal component analysis separated the stream in the preserved area from those in the urban area by having lower values of BOD, COD, sediment size, conductivity, detergents, pH, deposited solids and total dissolved solids. Pollution sensitive groups (e.g., Ephemeroptera and Trichoptera were associated to the stream in the preserved area, and more tolerant groups (e.g., Chironomidae and Oligochaeta had greater abundance in the streams of the urban area. Canonical Correspondence Analysis indicated that dissolved oxygen, conductivity, BOD, oil and grease, and turbidity explained 56% of the variance in the distribution and abundance of macroinvertebrates; CONCLUSIONS: Benthic communities of Vereda streams in urban areas in the Cerrado Biome seem to be highly affected by human activities that increase water organic pollution and sedimentation.OBJETIVO: Veredas e comunidades aquáticas e semi-aquáticas desempenham importante papel na proteção das bacias hidrográficas no Bioma Cerrado. Informações sobre efeitos de variáveis físico-químicas e da

  17. Quantification of environment-driven changes in epiphytic macroinvertebrate communities associated to Phragmites australis

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    Full Text Available The epiphytic macroinvertebrate communities associated with the Common Reed, Phragmites australis (Cav. Trin. ex Steudel, were examined seasonally from summer 2004 to spring 2005 in eleven coastal lagoons of the Llobregat Delta (NE Spain following the method proposed by Kornijów & Kairesalo (1994. The aims of the study were to: 1 characterise and quantify changes in epiphytic macroinvertebrate communities along environmental gradients; 2 assess the contribution of elements of the epiphytic compartment to structuring the community; 3 define the optima and tolerances of selected epiphytic macroinvertebrate taxa for the most relevant ecological factors responsible for assemblage composition; and 4 identify possible epiphytic species assemblages that would allow a lagoon’s typology to be established, as well as their representative indicator species. Communities showed statistically significant seasonal variation, with two faunal peaks: one in summer, with high chironomid densities, and the other in winter, with high naidid densities. These peaks showed a clear response to the influence of environmental factors. Salinity explained the highest percentage of total variance (36%, while trophic variables (nutrients, phytoplanktonic chlorophyll-a, and total organic carbon and epiphyton biomass (19.2 and 4% of total variance explained, respectively were secondary. Three different epiphytic macroinvertebrate species assemblages could be defined. These assemblages were directly linked to conductivity conditions, which determined the rate of survival of certain taxa, and to the existence of a direct connection with the sea, which permitted the establishment of "brackish-water" species. In spite of the existence of these species assemblages, the species composition and biomass of epiphytic macroinvertebrates and epiphyton differed substantially between lagoons; both elements were subject to changes in the environment, which finally determined the site

  18. Choosing the best non-parametric richness estimator for benthic macroinvertebrates databases Eligiendo el mejor estimador no paramétrico para calcular riqueza en bases de datos de macroinvertebrados bentónicos

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    Carola V. Basualdo


    Full Text Available Non-parametric estimators allow to compare the estimates of richness among data sets from heterogeneous sources. However, since the estimator performance depends on the species-abundance distribution of the sample, preference for one or another is a difficult issue. The present study recovers and revalues some criteria already present in the literature in order to choose the most suitable estimator for streams macroinvertebrates, and provides some tools to apply them. Two abundance and four incidence estimators were applied to a regional database at family and genus level. They were evaluated under four criteria: sub-sample size required to estimate the observed richness; constancy of the sub-sample size; lack of erratic behavior and similarity in curve shape through different data sets. Among incidence estimators, Jack1 had the best performance. Between abundance estimators, ACE was the best when the observed richness was small and Chao1 when the observed richness was high. The uniformity of curves shapes allowed to describe the general sequences of curves behavior that could act as references to compare estimations of small databases and to infer the possible behavior of the curve (i.e the expected richness if the sample were larger. These results can be very useful for environmental management, and update the state of knowledge of regional macroinvertebrates.Los estimadores no paramétricos permiten comparar la riqueza estimada de conjuntos de datos de origen diverso. Empero, como su comportamiento depende de la distribución de abundancia del conjunto de datos, la preferencia por alguno representa una decisión difícil. Este trabajo rescata algunos criterios presentes en la literatura para elegir el estimador más adecuado para macroinvertebrados bentónicos de ríos y ofrece algunas herramientas para su aplicación. Cuatro estimadores de incidencia y dos de abundancia se aplicaron a un inventario regional a nivel de familia y género. Para

  19. Controlling factors of benthic macroinvertebrates distribution in a small tropical pond, lateral to the Paranapanema River (São Paulo, Brazil Macroinvertebrados bentônicos e fatores controladores de sua distribuição em uma pequena lagoa tropical adjacente ao rio Paranapanema (São Paulo, Brasil

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    Erika Mayumi Shimabukuro


    Full Text Available AIM: The aim of the present study was to examine the benthic fauna in a marginal pond lateral to the Paranapanema River and to identify the main controlling factors of its distribution. Considering the small size of the lacustrine ecosystem, we expected that seasonal variations of the benthic community attributes are more important than spatial variations; METHODS: Two samplings, one in March and another in August, were carried out at nine sites in the pond. Sediment samples were obtained through a Van Veen grab for invertebrate sorting, granulometric analysis, and for quantification of organic matter in sediment. Other abiotic factors were measured, such as water transparency, dissolved oxygen, pH, electric conductivity, temperature, and depth of sediment sampling sites. Regarding the comparative analysis at spatial scale, no significant variations in density of the benthic invertebrate community were found. RESULTS: In relation to the studied abiotic factors, only depth presented significant differences among sampling sites; All the measured environmental parameters presented significant differences among sampling months, except depth and the physical and chemical characteristics of the sediment. The abundance of Chaoboridae and Chironomidae was the unique attribute with a significant difference in comparing the two months. A higher abundance of taxa occurred in August, especially for Oligochaeta, Nematoda, Chaoboridae, and Chironomidae; CONCLUSIONS: Because of the low structural complexity of the studied pond, we concluded that the changes in benthic macroinvertebrate community attributes were mainly due to seasonal effects.OBJETIVO: O presente estudo tem por objetivo examinar a fauna bentônica em lagoa marginal ao rio Paranapanema e os principais fatores reguladores da sua distribuição. Devido ao pequeno tamanho do ambiente lacustre, procurou-se mostrar que as variações sazonais dos atributos da comunidade bentônica são mais

  20. Seasonal mercury concentrations and {delta}{sup 15}N and {delta}{sup 13}C values of benthic macroinvertebrates and sediments from a historically polluted estuary in south central Chile

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    Diaz-Jaramillo, Mauricio, E-mail: [Aquatic Systems Research Unit, EULA Chile Environmental Sciences Centre, Universidad de Concepcion (Chile); Munoz, Claudia; Rudolph, Ignacio [Aquatic Systems Research Unit, EULA Chile Environmental Sciences Centre, Universidad de Concepcion (Chile); Servos, Mark [Department of Biology, University of Waterloo, ON (Canada); Barra, Ricardo [Aquatic Systems Research Unit, EULA Chile Environmental Sciences Centre, Universidad de Concepcion (Chile)


    The Lenga Estuary is one of the most industrialized sites in south central Chile where the historic operation of chlor-alkali plants resulted in large quantities of mercury (Hg) being deposited into the estuary. This historical contamination may still represent a risk to the biota in the estuary. To investigate this four macroinvertebrates, Neotrypaea uncinata (ghostshrimp), Elminius kingii (barnacle), Hemigrapsus crenulatus (shore crab) and Perinereis gualpensis (ragworm) were collected seasonally from three different sites in the Lenga Estuary and one in a reference estuary (Tubul Estuary), and analyzed for Hg and stable isotopes ({delta}{sup 15}N and {delta}{sup 13}C). Mercury concentrations in Lenga sediments ranged from 0.4 {+-} 0.1 to 13 {+-} 3 mg/kg, while those in Tubul sediments ranged from 0.02 {+-} 0.01 to 0.07 {+-} 0.09 mg/kg. Total Hg concentrations of invertebrates were significantly different between estuaries (p < 0.05), but not by species or season for each estuary (p > 0.05). In contrast, organic Hg concentrations were different by species and season with shore crab muscle tissues exhibiting the greatest percent difference. Site-specific relationships demonstrated that total Hg concentrations in ragworm best reflected the total Hg sediment mercury concentrations. Signatures of {delta}{sup 13}C were correlated to the organic Hg % rather than total Hg. This suggests that organic Hg concentrations in these species were related to the carbon sources. -- Highlights: Black-Right-Pointing-Pointer Hg in sediments and biota from Lenga Estuary were elevated compared to nearby estuary. Black-Right-Pointing-Pointer Invertebrates showed interspecific and seasonal differences in terms of organic Hg %. Black-Right-Pointing-Pointer Total Hg levels in the ragworm best reflect Hg sediment gradient in Lenga Estuary. Black-Right-Pointing-Pointer Interspecific variation in {delta}{sup 13}C signatures indicated different feeding modes. Black

  1. Long-term historical analysis of benthic communities and physical habitat in an agricultural stream in California's San Joaquin River watershed. (United States)

    Hall, Lenwood W; Killen, William D; Alden, Raymond


    This study was designed to characterize long-term annual temporal and spatial trends (2001 to 2007) in physical habitat and benthic communities and to determine relationships of habitat and benthic communities during this 7-year period in an agricultural stream in the San Joaquin River watershed in California (Del Puerto Creek). The canonical discriminant analysis indicated that there were no overall significant temporal patterns for the habitat metrics although spatial patterns were prominent for nearly all the habitat metrics. Channel alteration, riparian vegetative zone, bank stability, vegetative protection and frequency of riffles/bends were the primary habitat metrics associated with these site effects. Approximately 3,700 to 4,500 individual macroinvertebrates were picked and identified from five Del Puerto Creek sites sampled annually from 2001 to 2007. The total number of taxa by year ranged from 81 in 2003 to 106 in 2007. These benthic assemblages were generally comprised of tolerant to moderately tolerant taxa such as blackflies, oligochaetes, snails and chironomids. The metrics % predators, % EPT index, % collectors/filterers and % shredders were the benthic metrics that were most associated with the temporal effects. Ephemeroptera taxa, trichoptera taxa, and % sensitive EPT index were the benthic metrics that were most associated with the site effects. The most upstream site in Del Puerto Creek had the most robust and healthy benthic communites. Strong statistical relationships were reported between certain benthic metrics and habitat metrics. Overall, samples taken from site-year combinations with sediments that were qualitatively less muddy (less fines) and that had higher habitat metric scores for embeddedness, riparian vegetative zone, and channel alteration tended to have benthic communities characterized by higher values of the benthic metrics such as EPT taxa, Ephemeroptera taxa, EPT index, abundance, and taxonomic richness, among others

  2. Constitution of fish assemblages in three nearshore habitats and the effect of benthic macroalgae on fish assemblages in Gouqi Island%拘杞岛近岸3种生境鱼类群落组成及岩礁区底栖海藻对鱼类群落结构的影响

    Institute of Scientific and Technical Information of China (English)

    王蕾; 章守宇; 汪振华; 王凯; 林军


    Macroalgae covering on the rocky reef around coast of Gouqi Island were surveyed and sampled through diving during 2005 to 2006 and May to June 2010, in order to find out the distribution, constitution and life history of macroalgae. Two composing patterns of macroalgae were shown in the subtidal zone of rocky reef; one was dominated by standing macroalgae Sargassum horneri; another was dominated by smaller macroalgaes, such as Ulva pertusa, which is widely distributed both in intertidal and subtidal zone. The life history of S. Horneri showed the four stages of the larger kelp bed: young seedling development period (August to September) ,slow growth period of seeding (October to February in next year) ,fast growth and reproduction period (March to May) .decomposing and declining period (June to July). The smaller kelp bed exists the whole year, without much difference to outside of the kelp bed. To estimate the composition of fish assemblages in three habitats around Gouqi Island nearshore, I. E. Rocky reef, sandy beach and mussel cultivation rafts,we sampled the fish assemblages in three habitats by combined gill nets every month from February 2009 to January 2010. The indexes of Jaccard similarity, Margalef richness and Shannon-wiener diversity were used to compare the variety of fish community structures among habitats, combined with statistical analysis of variance, UPGMA and nMDS. It showed that the differences of fish community structures among above three habitats were significant. The dominant fish species in rocky reef habitat were Sebastiscus marmoratus, Agrammus agrammus and N. Albiflora. Fish community was mainly based on the demersal omnivorous rocky fishes, which prey mainly on benthic invertebrates living on macroalgaes. The dominant fish species in sandy beach habitat were Paraplagusia japonica and Nibea albiflora. Fish community was mainly based on the mid-lower migration fishes. For fish assemblages in mussel cultivation raft habitat, which were

  3. Macroinvertebrados bentónicos como indicadores de calidad de agua de ríos del sur de Chile Benthic macroinvertebrates as indicators of water quality of southern Chile rivers

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    Full Text Available La Cuenca Hidrográfica del Río Damas (40°39' S, 72°23' O, presenta una intensa actividad agrícola y ganadera en un 78,2 % de su superficie, lo cual se ha traducido en importantes aportes de nutrientes al ecosistema acuático. Los objetivos de este estudio fueron: (a analizar la distribución espacial de la macrofauna bentónica en la cuenca y (b determinar la viabilidad de utilizar el Índice Biótico de Familias (IBF para evaluación de la calidad de las aguas. Los muestreos se realizaron en enero de 1998 con una red Surber (0,09 m², en 15 sitios distribuidos en el curso principal y sus tributarios. Se registró un total de 77 taxa, siendo los grupos más diversos Plecoptera (16 %, Trichoptera (16 %, Diptera (14 % y Ephemeroptera (12 %. Se observó una marcada tendencia a la disminución de riqueza específica desde la cabecera de la cuenca hacia aguas abajo. Las abundancias, biomasas y el IBF, presentaron una tendencia inversa a la riqueza específica. IBF se correlacionó significativa y positivamente con el fósforo total (r² = 0,71, temperatura (r² = 0,66, nitrito (r² = 0,56, conductividad eléctrica (r² = 0,50, demanda biológica de oxígeno (r² = 0,46 y nitrógeno total (r² = 0,46, y negativamente con oxígeno disuelto (r² = 0,53, variables estrechamente asociadas al uso intensivo de fertilizantes en la cuenca. Los resultados sugieren que el IBF es un buen indicador de la calidad de las aguas de los ríos de cuencas agrícolas y ganaderas del sur de ChileThe Damas River Hydrographic Basin (40°39'S, 72°23' W presents an intense agricultural and cattle ranching activities in 78.2 % of its surface, which has resulted in important inputs of nutrients into the aquatic ecosystem. The objectives of this study were: (a to analyze the spatial distribution of the benthic macrofauna in the Damas basin, and (b to determine the feasibility of using the Families Biotic Index (FBI for the evaluation of water quality. The samplings were

  4. Rising from the ashes: Changes in salmonid fish assemblages after 30 months of the Puyehue-Cordon Caulle volcanic eruption. (United States)

    Lallement, Mailén; Macchi, Patricio J; Vigliano, Pablo; Juarez, Santiago; Rechencq, Magalí; Baker, Matthew; Bouwes, Nicolaas; Crowl, Todd


    Events such as volcanic eruptions may act as disturbance agents modifying the landscape spatial diversity and increasing environmental instability. On June 4, 2011 the Puyehue-Cordon Caulle volcanic complex located on Chile (2236 m.a.s.l., 40° 02' 24" S- 70° 14' 26" W) experience a rift zone eruption ejecting during the first day 950 million metric tons into the atmosphere. Due to the westerly winds predominance, ash fell differentially upon 24 million ha of Patagonia Argentinean, been thicker deposits accumulated towards the West. In order to analyze changes on stream fish assemblages we studied seven streams 8, 19 and 30 months after the eruption along the ash deposition gradient, and compare those data to pre eruption ones. Habitat features and structure of the benthic macroinvertebrate food base of fish was studied. After the eruption, substantial environmental changes were observed in association with the large amount of ash fallout. In western sites, habitat loss due to ash accumulation, changes in the riparian zone and morphology of the main channels were observed. Turbidity was the water quality variable which reflected the most changes throughout time, with NTU values decreasing sharply from West to East sites. In west sites, increased Chironomid densities were recorded 8 months after the initial eruption as well as low EPT index values. These relationships were reversed in the less affected streams farther away from the volcano. Fish assemblages were greatly influenced both by habitat and macroinvertebrate changes. The eruption brought about an initial sharp decline in fish densities and the almost total loss of young of the year in the most western streams affecting recruitment. This effect diminished rapidly with distance from the emission center. Thirty months after the eruption, environmental changes are still occurring as a consequence of basin wide ash remobilization and transport.

  5. Relationship between Decomposition Rates of Two Leaves and Colonization Benthic Macroinvertebrate in the Stream of Yabuli Mountain%亚布力山涧溪流2种树叶的分解速率与大型底栖动物定殖关系

    Institute of Scientific and Technical Information of China (English)

    阚春梅; 刘曼红; 王令刚; 于洪贤


    利用分解网袋(孔径为1 mm)在亚布力山涧一级溪流中对水曲柳( Fraxinus mandshurica)和暴马丁香( Syringa reticulate var.mandshurica)进行了为期105 d的树叶分解研究。结果表明:水曲柳和暴马丁香树叶的分解速率分别为0.04、0.02,符合指数衰减模型,均属于快速分解组。定殖在水曲柳、暴马丁香树叶上的底栖动物种类分别为46、44种,二者均以双翅目摇蚊为主,分别占底栖动物类群数的60.9%和45.5%。从大型底栖动物摄食功能群的比例来看,定殖在水曲柳叶片上直接集食者比例最高,为52.3%;其次是撕食者(25.5%)和捕食者(19.9%);最少的为杂食者,占2.3%。而定殖在暴马丁香叶片上直接集食者为45.2%;其次为捕食者(30.9%)和撕食者(19.1%);收集者最少,占4.8%。说明夏秋两季在亚布力山涧溪流中直接集食的底栖动物丰富度与树叶分解速率有显著关系。%The experiment was conducted to study the leaves decomposition rates of Fraxinus mandshurica and Syringa reticulate with decomposition bags ( diameter of 1 mm) for 105 days in the stream of Yabuli Mountain.The leaves decomposition rates of Fraxinus mandshurica and Syringa reticulate are 0.04 and 0.02, and the decomposition rate accorded with expo-nential decay model.Leaves of two species belong to the rapid decomposition groups.In the whole experiment process, the species numbers colonization benthic macroinvertebrate of the leaf Fraxinus mandshurica (46) is higher than that of Syrin-ga reticulate leaves (44), and both belong to Diptera Chironomus, accounting for 60.9% and 45.5% of benthic animal groups.From functional feeding groups, the gatherers/collectors in Fraxinus mandshurica are dominant (52.3%), fol-lowed by the shredders (25.5%) and the predators (19.9%), respectively.The omnivores are rare (2.3%).There is significant relationship between

  6. The effects of tricyclazole treatment on aquatic macroinvertebrates in the field and in laboratory

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    B. Rossaro


    Full Text Available The effects of tricyclazole treatments on benthic macroinvertebrates in the field and in laboratory were studied. In field conditions, low density of benthic populations was observed, both in treated and untreated plots, which was attributed to the short period of submersion of the rice field and high water temperature, fungicide treatments had no significant effect. Both laboratory acute toxicity test and a test using a mesocosm suggested a low toxicity of tricyclazole on invertebrates. A reduction of the macroinvertebrate density was observed only when tricyclazole concentration was applied at concentrations 100 times the ones tested in the field, acute toxicity test gave an LC50 after 48 h of 26 mg*L–1, in agreement with data obtained for other species.

  7. A Benthic Invertebrate Survey of Jun Jaegyu Volcano: An active undersea volcano in Antarctic Sound, Antarctica (United States)

    Quinones, G.; Brachfeld, S.; Gorring, M.; Prezant, R. S.; Domack, E.


    Jun Jaegyu volcano, an Antarctic submarine volcano, was dredged in May 2004 during cruise 04-04 of the RV Laurence M. Gould to determine rock, sediment composition and marine macroinvertebrate diversity. The objectives of this study are to examine the benthic assemblages and biodiversity present on a young volcano. The volcano is located on the continental shelf of the northeastern Antarctic Peninsula, where recent changes in surface temperature and ice shelf stability have been observed. This volcano was originally swath-mapped during cruise 01-07 of the Research Vessel-Ice Breaker Nathaniel B. Palmer. During LMG04-04 we also studied the volcano using a SCUD video camera, and performed temperature surveys along the flanks and crest. Both the video and the dredge indicate a seafloor surface heavily colonized by benthic organisms. Indications of fairly recent lava flows are given by the absence of marine life on regions of the volcano. The recovered dredge material was sieved, and a total of thirty-three invertebrates were extracted. The compilation of invertebrate community data can subsequently be compared to other benthic invertebrate studies conducted along the peninsula, which can determine the regional similarity of communities over time, their relationship to environmental change and health, if any, and their relationship to geologic processes in Antarctic Sound. Twenty-two rock samples, all slightly weathered and half bearing encrusted organisms, were also analyzed using inductively coupled plasma-optical emission spectrometry (ICP-OES). Except for one conglomerate sample, all are alkali basalts and share similar elemental compositions with fresh, unweathered samples from the volcano. Two of the encrusted basalt samples have significantly different compositions than the rest. We speculate this difference could be due to water loss during sample preparation, loss of organic carbon trapped within the vesicles of the samples and/or elemental uptake by the

  8. Benthic Cover (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Benthic cover (habitat) maps are derived from aerial imagery, underwater photos, acoustic surveys, and data gathered from sediment samples. Shallow to moderate-depth...

  9. Benthic foraminifera

    Digital Repository Service at National Institute of Oceanography (India)

    Saraswat, R.; Nigam, R.

    (Nolet and Corliss, 1990). Differences in the abundance of oxygen-sensitive and dissolution-prone benthic foraminiferal species between the Last Glacial Maximum (LGM) and the Holocene in the abyssal waters of the southwestern Gulf of Mexico were used... (2009) Deep-sea benthic diversity linked to seasonality of pelagic productivity. Deep Sea Research Part I: Oceanographic Research Papers 56: 835-841. Culver S (1988) New foraminiferal depth zonation of the northwestern Gulf of Mexico. Palaios 3: 69...

  10. Habitat Specialization in Tropical Continental Shelf Demersal Fish Assemblages


    Ben M Fitzpatrick; Euan S Harvey; Heyward, Andrew J.; Twiggs, Emily J.; Jamie Colquhoun


    The implications of shallow water impacts such as fishing and climate change on fish assemblages are generally considered in isolation from the distribution and abundance of these fish assemblages in adjacent deeper waters. We investigate the abundance and length of demersal fish assemblages across a section of tropical continental shelf at Ningaloo Reef, Western Australia, to identify fish and fish habitat relationships across steep gradients in depth and in different benthic habitat types. ...

  11. Change does not happen overnight: a case study on stream macroinvertebrates

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    Guareschi S.


    Full Text Available The influence of day/night conditions on individual animal/plant species has been widely studied, but diel cycle studies of the entire stream macroinvertebrate community are extremely rare. This study explored potential dissimilarities between daytime and nighttime macroinvertebrate assemblages by extensive fieldwork conducted in the Lemme stream, a natural water course of NW Italy. Here numerous structural and functional metrics (richness, abundance, biomass, indicator taxa, composition, biomonitoring values and feeding groups were evaluated at the family level. Small-scale environmental variables were investigated to understand possible differences between macroinvertebrate assemblages in the daytime/nighttime. After collecting and identifying 21 459 organisms of 50 taxa, Chironomidae (Diptera was the most abundant under both day and night conditions. Our findings stressed that similar results and biological information on daytime/nighttime data were obtained. No marked differences could be related to various factors: heterotrophic condition of small-order streams, presence of aquatic predators under night and day conditions, absence of taxa with a specific phototaxis. Of all the environmental variables, velocity was always the most important in both situations, with some differences detected in the importance of the second variable (riverbed substrate diameter. This research, and future studies on different conditions and geographic areas, will contribute knowledge on stream macroinvertebrate diel activity, and provide useful information about efficient sampling strategies.

  12. Diversity of aquatic insects and other associated macroinvertebrates in an arid wetland (Mendoza Province, Argentina)



    The goal of this work was to expand the evaluation of diversity of aquatic insects and associated macroinvertebrates along the Bañado Carilauquen using hand net for water column and Petersen dredge for benthos. Additionally, we explored seasonal and spatial differences and similarities of macro invertebrate assemblages' qualitative composition. Samplings were conducted seasonally in five reaches of the Bañado Carilauquen, from headwaters to outlet. A total of 47 taxa were identified; 37 of th...

  13. Strange Assemblage

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    David Robert Cole


    Full Text Available This paper contends that the power of Deleuze & Guattari’s (1988 notion of assemblage as theorised in 1000 Plateaus can be normalised and reductive with reference to its application to any social-cultural context where an open system of dynamic and fluid elements are located. Rather than determining the assemblage in this way, this paper argues for an alternative conception of ‘strange assemblage’ that must be deliberately and consciously created through rigorous and focused intellectual, creative and philosophical work around what makes assemblages singular. The paper will proceed with examples of ‘strange assemblage’ taken from a film by Peter Greenaway (A Zed and 2 Noughts; the film ‘Performance’; educational research with Sudanese families in Australia; the book, Bomb Culture by Jeff Nuttall (1970; and the band Hawkwind. Fittingly, these elements are themselves chosen to demonstrate the concept of ‘strange assemblage’, and how it can be presented. How exactly the elements of a ‘strange assemblage’ come together and work in the world is unknown until they are specifically elaborated and created ‘in the moment’. Such spontaneous methodology reminds us of the 1960s ‘Happenings’, the Situationist International and Dada/Surrealism. The difference that will be opened up by this paper is that all elements of this ‘strange assemblage’ cohere in terms of a rendering of ‘the unacceptable.'

  14. Structural and functional responses of benthic invertebrates to imidacloprid in outdoor stream mesocosms

    Energy Technology Data Exchange (ETDEWEB)

    Pestana, J.L.T., E-mail: jpestana@ua.p [CESAM and Departamento de Biologia, Universidade de Aveiro, Campus Universitario de Santiago, 3810-193 Aveiro (Portugal); Environment Canada at Canadian Rivers Institute, Department of Biology, University of New Brunswick, 10 Bailey Drive, Fredericton, NB (Canada); Alexander, A.C., E-mail: alexa.alexander@unb.c [Environment Canada at Canadian Rivers Institute, Department of Biology, University of New Brunswick, 10 Bailey Drive, Fredericton, NB (Canada); Culp, J.M., E-mail: jculp@unb.c [Environment Canada at Canadian Rivers Institute, Department of Biology, University of New Brunswick, 10 Bailey Drive, Fredericton, NB (Canada); Baird, D.J., E-mail: djbaird@unb.c [Environment Canada at Canadian Rivers Institute, Department of Biology, University of New Brunswick, 10 Bailey Drive, Fredericton, NB (Canada); Cessna, A.J., E-mail: asoares@ua.p [Environment Canada, National Hydrology Research Centre, 11 Innovation Boulevard, Saskatoon, SK (Canada); Soares, A.M.V.M., E-mail: asoares@ua.p [CESAM and Departamento de Biologia, Universidade de Aveiro, Campus Universitario de Santiago, 3810-193 Aveiro (Portugal)


    Structural and functional responses of a benthic macroinvertebrate assemblage to pulses of the insecticide imidacloprid were assessed in outdoor stream mesocosms. Imidacloprid pulses reduced invertebrate abundance and community diversity in imidacloprid-dosed streams compared to control streams. These results correlated well with effects of imidacloprid on leaf litter decomposition and feeding rates of Pteronarcys comstocki, a stonefly, in artificial streams. Reductions in oxygen consumption of stoneflies exposed to imidacloprid were also observed in laboratory experiments. Our findings suggest that leaf litter degradation and single species responses can be sensitive ecotoxicological endpoints that can be used as early warning indicators and biomonitoring tools for pesticide contamination. The data generated illustrates the value of mesocosm experiments in environmental assessment and how the consideration of functional and structural endpoints of natural communities together with in situ single species bioassays can improve the evaluation and prediction of pesticide effects on stream ecosystems. - Combining organism-level responses with community-level processes for the evaluation and prediction of pesticide effects on stream ecosystems.

  15. Evaluating macroinvertebrate community shifts in the confluence of freestone and limestone streams

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    Jennifer K. Hellmann


    Full Text Available Aquatic macroinvertebrates are critical to ecosystem functioning through their regulation of many essential top-down and bottom-up ecosystem processes such as energy translocation, nutrient flow, and detrital decomposition. However, specific preferences by macroinvertebrates for certain ranges of abiotic and biotic characteristics mean that changes in these factors often create large differences in benthic community structure. Investigations into drivers of community structure have found distinct patterns of variation between ecosystems, but drivers of macroscale variation may differ from drivers of microscale variation. Such microscale variation in macroinvertebrate community structure as a function of abiotic conditions may be found in the confluence of two geologically distinct freshwater streams. Variation in the origin, underlying bedrock, and watershed of a stream results in drastically different physical and chemical characteristics and correspondingly distinct macroinvertebrate community structures. In areas where water from geologically distinct streams flows together, a mixing zone emerges with unique chemical and physical characteristics. There is little information on how invertebrate communities are structured within this mixing zone. To investigate this, we examined how the structure of the macroinvertebrate community changed downstream of the confluence. Up to thirty metres downstream, we found distinct stream sections that mirrored physical and chemical conditions found in limestone and freestone streams, and a mixing zone with emergent properties. These physical and chemical changes between sites were accompanied by shifts in macroinvertebrate community composition. Diversity indices indicated significantly higher diversity in freestone sites than in limestone sites or the mixing zone and there was a unique composition of genera in the mixing zone that were distinct from both limestone and freestone sites. Factors driving

  16. Macroinvertebrates of the Iranian running waters: a review

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    Moslem Sharifinia


    Full Text Available Abstract A comprehensive review of macroinvertebrate studies conducted along the Iranian running waters over the last 15 years has been made by providing the most updated checklist of the Iranian running waters benthic invertebrates. Running waters ecosystems are complex environments known for their importance in terms of biodiversity. As part of the analysis, we endeavored to provide the critical re-identification of the reported species by through comparisons with the database of the Animal Diversity Web (ADW and appropriate literature sources or expert knowledge. A total of 126 species belonging to 4 phyla have been compiled from 57 references. The phylum Arthropoda was found to comprise the most taxa (n = 104 followed by Mollusca, Annelida and Platyhelminthes. Ongoing efforts in the Iranian running waters regarding biomonitoring indices development, testing, refinement and validation are yet to be employed in streams and rivers. Overall, we suggest that future macroinvertebrate studies in Iranian running waters should be focused on long-term changes by broadening target species and strong efforts to publish data in peer-reviewed journals in English.

  17. Mussel colonization of a high flow artificial benthic habitat : Byssogenesis holds the key

    NARCIS (Netherlands)

    Rajagopal, S.; Venugopalan, V.P.; Velde, G. van der; Jenner, H.A.


    Water flow is an important characteristic determining the settlement and growth of macroinvertebrates in the marine environment. Intake systems of coastal power stations offer a unique opportunity to study the effect of water flow on benthic organisms under field conditions. The cooling water intake

  18. Macroinvertebrate Community Responses to the Chemical Removal of Phragmites in a Lake Erie Coastal Wetland (United States)

    Kulesza, A. E.; Holomuzki, J. R.; Klarer, D. M.


    The invasive giant reed, Phragmites australis, can quickly form near-monotypic stands in North American wetlands, and as a result, sometimes reduce system biodiversity. However, the effects of Phragmites, and of the glyphosate herbicides used to control it, on trophic structure in benthic communities in these systems are less well known. Our study compares macroinvertebrate, algal, and juvenile fish diversity in replicate 10 x 5 m stands of Typha angustifolia (narrow-leaf cattail), glyphosate-sprayed Phragmites, and unsprayed Phragmites in a Lake Erie coastal wetland in Huron, Ohio. Macroinvertebrate diversity and proportions of functional feeding groups did not differ among stand types. However, overall densities of macroinvertebrates did vary among stands. Snails and larval chironomids and odonates were typically higher in Phragmites than in Typha stands. Interactions between changing water levels, algal densities, and prevailing flow patterns partly explain these outcomes. Ovipositing adult odonates did not prefer a particular stand type. Similarly, captures of juvenile fish did not vary among stands. Our results suggest that Phragmites, at least in small to moderately sized-patches, and herbicide application to these patches, does not detrimentally affect diversity in wetland, benthic communities.

  19. Variation in biotic assemblages and stream-habitat data with sampling strategy and method in tidal segments of Highland and Marchand Bayous, Galveston County, Texas, 2007 (United States)

    Mabe, Jeffrey A.; Moring, J. Bruce


    The U.S. Geological Survey, in cooperation with the Houston-Galveston Area Council and the Galveston Bay Estuary Program under the authority of the Texas Commission on Environmental Quality, did a study in 2007 to assess the variation in biotic assemblages (benthic macroinvertebrate and fish communities) and stream-habitat data with sampling strategy and method in tidal segments of Highland Bayou and Marchand Bayou in Galveston County. Data were collected once in spring and once in summer 2007 from four stream sites (reaches) (short names Hitchcock, Fairwood, Bayou Dr, and Texas City) of Highland Bayou and from one reach (short name Marchand) in Marchand Bayou. Only stream-habitat data from summer 2007 samples were used for this report. Additional samples were collected at the Hitchcock, Fairwood, and Bayou Dr reaches (multisample reaches) during summer 2007 to evaluate variation resulting from sampling intensity and location. Graphical analysis of benthic macroinvertebrate community data using a multidimensional scaling technique indicates there are taxonomic differences between the spring and summer samples. Seasonal differences in communities primarily were related to decreases in the abundance of chironomids and polychaetes in summer samples. Multivariate Analysis of Similarities tests of additional summer 2007 benthic macroinvertebrate samples from Hitchcock, Fairwood, and Bayou Dr indicated significant taxonomic differences between the sampling locations at all three reaches. In general, the deepwater samples had the smallest numbers for benthic macroinvertebrate taxa richness and abundance. Graphical analysis of species-level fish data indicates no consistent seasonal difference in fish taxa across reaches. Increased seining intensity at the multisample reaches did not result in a statistically significant difference in fish communities. Increased seining resulted in some changes in taxa richness and community diversity metrics. Diversity increases

  20. Long-Term Changes in the Water Quality and Macroinvertebrate Communities of a Subtropical River in South China


    Kun Li; Chunguang He; Jie Zhuang; Zhenxing Zhang; Hongyong Xiang; Zhongqiang Wang; Haijun Yang; Lianxi Sheng


    Subtropical rivers support a highly diverse array of benthic macroinvertebrates. In this study, by combining historical data and new data, we identified specific changes in the Guanlan River, in South China, from 1981 to 2011, and evaluated the effectiveness of an ecological restoration project under highly polluted conditions. From 1981 to 2011, the water quality in the Guanlan River underwent three major stages. With the deterioration of water quality, there was an overall decrease in the s...

  1. Evaluation of Macroinvertebrate Communities and Habitat for Selected Stream Reaches at Los Alamos National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    L.J. Henne; K.J. Buckley


    This is the second aquatic biological monitoring report generated by Los Alamos National Laboratory's (LANL's) Water Quality and Hydrology Group. The study has been conducted to generate impact-based assessments of habitat and water quality for LANL waterways. The monitoring program was designed to allow for the detection of spatial and temporal trends in water and habitat quality through ongoing, biannual monitoring of habitat characteristics and benthic aquatic macroinvertebrate communities at six key sites in Los Alamos, Sandia, Water, Pajarito, and Starmer's Gulch Canyons. Data were collected on aquatic habitat characteristics, channel substrate, and macroinvertebrate communities during 2001 and 2002. Aquatic habitat scores were stable between 2001 and 2002 at all locations except Starmer's Gulch and Pajarito Canyon, which had lower scores in 2002 due to low flow conditions. Channel substrate changes were most evident at the upper Los Alamos and Pajarito study reaches. The macroinvertebrate Stream Condition Index (SCI) indicated moderate to severe impairment at upper Los Alamos Canyon, slight to moderate impairment at upper Sandia Canyon, and little or no impairment at lower Sandia Canyon, Starmer's Gulch, and Pajarito Canyon. Habitat, substrate, and macroinvertebrate data from the site in upper Los Alamos Canyon indicated severe impacts from the Cerro Grande Fire of 2000. Impairment in the macroinvertebrate community at upper Sandia Canyon was probably due to effluent-dominated flow at that site. The minimal impairment SCI scores for the lower Sandia site indicated that water quality improved with distance downstream from the outfall at upper Sandia Canyon.

  2. On the benthic molluscs of Banco Inglés (Río de la Plata, Uruguay

    Directory of Open Access Journals (Sweden)

    Carranza, A.


    Full Text Available We describe the specific richness and community structure of benthic molluscs on a shallow-water sandy bank (Banco Inglés in the Río de la Plata estuary. From a total of 25 macroinvertebrate taxa collected, that included one ophiuroid, one bryozoan, fourcrustaceans and four polychaete species, molluscs were the dominant taxon, with 15 species recorded. These were one species of Polyplacophora, eight Bivalvia and six Gastropoda (one exotic, representing 11families and 11 genera. In terms of mean relative abundance, the molluscan assemblage was dominated by the deposit-feeder bivalve Corbula caribaea, averaging ca. 30% of the individuals of the macroinfauna. The alien species Rapana venosa was noted in two stations, represented by one and four specimens. We used null model analysis to test for nonrandomness in the structure of the molluscan communities of the area. The analysis supported the null hypothesis that co-occurrence patterns could not be distinguished from those that might arise by random processes.

  3. An experimental mesocosm study of microhabitat preferences and mobility in benthic foraminifera: Preliminary results.

    NARCIS (Netherlands)

    Ernst, S.R.; Duijnstee, Ivo; Jannink, N.T.; van der Zwaan, Bert


    Three small microcosm experiments were carried out to study the microhabitat preferences and mobility of benthic foraminifera from the northern Adriatic Sea. Following initial homogenization, the foraminiferal assemblages developed a clear microhabitat partitioning in the microcosms within 20 days.

  4. Responses of epibenthic and nektonic macroinvertebrate communities to a gradient of fish size in ponds

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    Marek Nieoczym


    Full Text Available Size relationships between fish and organisms from adjacent trophic levels are crucial for predicting the structure and dynamics of aquatic ecosystems. We compared macroinvertebrate communities along a fish-size gradient created by separate stocking of three age cohorts of common carp Cyprinus carpio in semi-natural ponds. The specific size range of fish (small, medium and large corresponding to fish age in ponds was the factor most strongly associated with macroinvertebrate composition. The other significant habitat variables were dissolved oxygen concentration in the water and submerged vegetation abundance in the open-water zone. Among the most numerous taxa in the ponds, relative abundances of Hirudinea, Gastropoda, Odonata and Coleoptera were larger in the presence of small-sized than of larger-sized carp. However, fish size effect was not linear, in that macroinvertebrate assemblages were less similar between ponds containing medium- vs large-sized fish than between ponds with small- vs large-sized fish. The dissimilarity patterns were mainly determined by disparities in abundance of Corixidae, which unlike other taxa common in the ponds occurred in the greatest numbers in the presence of large-sized carp. Macroinvertebrate diversity was greatest in ponds with small-sized fish and was positively related to emergent macrophyte cover. Enhancement of emergent vegetation is recommended as the most effective management strategy to buffer adverse impacts of fish on macroinvertebrates. If fish are present in the system, assessment of the size structure of fish populations can be advantageous in unravelling the essential processes driving the variation in pond communities.

  5. Sediment Burial Intolerance of Marine Macroinvertebrates.

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    Vicki J Hendrick

    Full Text Available The marine environment contains suspended particulate matter which originates from natural and anthropogenic sources. Settlement of this material can leave benthic organisms susceptible to smothering, especially if burial is sudden i.e. following storms or activities such as dredging. Their survival will depend on their tolerance to, and their ability to escape from burial. Here we present data from a multi-factorial experiment measuring burial responses incorporating duration, sediment fraction and depth. Six macroinvertebrates commonly found in sediment rich environments were selected for their commercial and/or conservation importance. Assessments revealed that the brittle star (Ophiura ophiura, the queen scallop (Aequipecten opercularis and the sea squirt (Ciona intestinalis were all highly intolerant to burial whilst the green urchin (Psammichinus miliaris and the anemone (Sagartiogeton laceratus, showed intermediate and low intolerance respectively, to burial. The least intolerant, with very high survival was the Ross worm (Sabellaria spinulosa. With the exception of C. intestinalis, increasing duration and depth of burial with finer sediment fractions resulted in increased mortality for all species assessed. For C. intestinalis depth of burial and sediment fraction were found to be inconsequential since there was complete mortality of all specimens buried for more than one day. When burial emergence was assessed O. ophiura emerged most frequently, followed by P. miliaris. The former emerged most frequently from the medium and fine sediments whereas P. miliaris emerged more frequently from coarse sediment. Both A. opercularis and S. laceratus showed similar emergence responses over time, with A. opercularis emerging more frequently under coarse sediments. The frequency of emergence of S. laceratus increased with progressively finer sediment and C. intestinalis did not emerge from burial irrespective of sediment fraction or depth. Finally

  6. Bottom fish assemblages at the shelf and continental slope off East Greenland

    DEFF Research Database (Denmark)

    Jørgensen, Ole A; Hvingel, Carsten; Møller, P.R.


    benthic species were used for analyses of the fish fauna diversity and fish assemblages. Nine assemblages were found by a standard type of cluster analysis. A Bayesian multinomial logit model was then applied to calculate vectors of probabilities defining the likelihood of each haul belonging to each...

  7. Legacy of a Chemical Factory Site: Contaminated Groundwater Impacts Stream Macroinvertebrates. (United States)

    Rasmussen, Jes J; McKnight, Ursula S; Sonne, Anne Th; Wiberg-Larsen, Peter; Bjerg, Poul L


    Legislative and managing entities of EU member states face a comprehensive task because the chemical and ecological impacts of contaminated sites on surface waters must be assessed. The ecological assessment is further complicated by the low availability or, in some cases, absence of ecotoxicity data for many of the compounds occurring at contaminated sites. We studied the potential impact of a contaminated site, characterised by chlorinated solvents, sulfonamides, and barbiturates, on benthic macroinvertebrates in a receiving stream. Most of these compounds are characterised by low or unknown ecotoxicity, but they are continuously discharged into the stream by way of a long-lasting source generating long-term chronic exposure of the stream biota. Our results show that taxonomical density and diversity of especially sediment dwelling taxa were reduced by >50 % at the sampling sites situated in the primary inflow zone of the contaminated GW. Moreover, macroinvertebrate communities at these sampling sites could be distinguished from those at upstream control sites and sites situated along a downstream dilution gradient using multidimensional scaling. Importantly, macroinvertebrate indices currently used did not identify this impairment, thus underpinning an urgent need for developing suitable tools for the assessment of ecological effects of contaminated sites in streams.

  8. Long-Term Changes in the Water Quality and Macroinvertebrate Communities of a Subtropical River in South China

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    Kun Li


    Full Text Available Subtropical rivers support a highly diverse array of benthic macroinvertebrates. In this study, by combining historical data and new data, we identified specific changes in the Guanlan River, in South China, from 1981 to 2011, and evaluated the effectiveness of an ecological restoration project under highly polluted conditions. From 1981 to 2011, the water quality in the Guanlan River underwent three major stages. With the deterioration of water quality, there was an overall decrease in the species number of macroinvertebrates in the Guanlan River, an increase in macroinvertebrate density, and a reduction of the biodiversity, and a reduction of functional feeding groups. In 2011, after five years of comprehensive remediation, the Guanlan River was somewhat improved. Macroinvertebrate biodiversity in the middle reach of the Guanlan River, where a key ecological restoration engineering project was implemented, did not differ significantly from other sites. This finding indicates that the effectiveness of ecological restoration measures in highly polluted rivers, particularly at the reach-scale, is very limited and even ineffective.

  9. Differences found in the macroinvertebrate community composition in the presence or absence of the invasive alien crayfish, Orconectes hylas (United States)

    Freeland-Riggert, Brandye T.; Cairns, Stefan H.; Poulton, Barry C.; Riggert, Chris M.


    Introductions of alien species into aquatic ecosystems have been well documented, including invasions of crayfish species; however, little is known about the effects of these introductions on macroinvertebrate communities. The woodland crayfish (Orconectes hylas (Faxon)) has been introduced into the St. Francis River watershed in southeast Missouri and has displaced populations of native crayfish. The effects of O. hylas on macroinvertebrate community composition were investigated in a fourth-order Ozark stream at two locations, one with the presence of O. hylas and one without. Significant differences between sites and across four sampling periods and two habitats were found in five categories of benthic macroinvertebrate metrics: species richness, percent/composition, dominance/diversity, functional feeding groups, and biotic indices. In most seasons and habitat combinations, the invaded site had significantly higher relative abundance of riffle beetles (Coleoptera: Elmidae), and significantly lower Missouri biotic index values, total taxa richness, and both richness and relative abundance of midges (Diptera: Chironomidae). Overall study results indicate that some macroinvertebrate community differences due to the O. hylas invasion were not consistent between seasons and habitats, suggesting that further research on spatial and temporal habitat use and feeding ecology of Ozark crayfish species is needed to improve our understanding of the effects of these invasions on aquatic communities.

  10. Modeling Aquatic Macroinvertebrate Richness Using Landscape Attributes

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    Marcia S. Meixler


    Full Text Available We used a rapid, repeatable, and inexpensive geographic information system (GIS approach to predict aquatic macroinvertebrate family richness using the landscape attributes stream gradient, riparian forest cover, and water quality. Stream segments in the Allegheny River basin were classified into eight habitat classes using these three landscape attributes. Biological databases linking macroinvertebrate families with habitat classes were developed using life habits, feeding guilds, and water quality preferences and tolerances for each family. The biological databases provided a link between fauna and habitat enabling estimation of family composition in each habitat class and hence richness predictions for each stream segment. No difference was detected between field collected and modeled predictions of macroinvertebrate families in a paired t-test. Further, predicted stream gradient, riparian forest cover, and total phosphorus, total nitrogen, and suspended sediment classifications matched observed classifications much more often than by chance alone. High gradient streams with forested riparian zones and good water quality were predicted to have the greatest macroinvertebrate family richness and changes in water quality were predicted to have the greatest impact on richness. Our findings indicate that our model can provide meaningful landscape scale macroinvertebrate family richness predictions from widely available data for use in focusing conservation planning efforts.

  11. The influence of connectivity in forest patches, and riparian vegetation width on stream macroinvertebrate fauna

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    IC Valle

    Full Text Available We assessed two dimensions of stream connectivity: longitudinal (between forest patches along the stream and lateral (riparian vegetation, using macroinvertebrate assemblages as bioindicators. Sites representing different land-uses were sampled in a lowland basin that holds a mosaic of protected areas. Land-use analysis, forest successional stages and riparian zone widths were calculated by the GIS analysis. Macroinvertebrate fauna was strongly affected by land-use. We observed a continuous decrease in the number of sensitive species, %Shredders and IBE-IOC biotic index from the upstream protected area to highly deforested sites, increasing again where the stream crosses a Biological Reserve. When analysing buffer strips, we found aquatic fauna responding to land-use alterations beyond the 30 m riparian corridor (60 m and 100 m wide. We discussed the longitudinal connectivity between forest patches and the riparian vegetation buffer strips necessary to hold high macroinvertebrate diversity. We recommend actions for the increase/maintenance of biodiversity in this and other lowland basins.

  12. The influence of connectivity in forest patches, and riparian vegetation width on stream macroinvertebrate fauna. (United States)

    Valle, I C; Buss, D F; Baptista, D F


    We assessed two dimensions of stream connectivity: longitudinal (between forest patches along the stream) and lateral (riparian vegetation), using macroinvertebrate assemblages as bioindicators. Sites representing different land-uses were sampled in a lowland basin that holds a mosaic of protected areas. Land-use analysis, forest successional stages and riparian zone widths were calculated by the GIS analysis. Macroinvertebrate fauna was strongly affected by land-use. We observed a continuous decrease in the number of sensitive species, %Shredders and IBE-IOC biotic index from the upstream protected area to highly deforested sites, increasing again where the stream crosses a Biological Reserve. When analysing buffer strips, we found aquatic fauna responding to land-use alterations beyond the 30 m riparian corridor (60 m and 100 m wide). We discussed the longitudinal connectivity between forest patches and the riparian vegetation buffer strips necessary to hold high macroinvertebrate diversity. We recommend actions for the increase/maintenance of biodiversity in this and other lowland basins.

  13. Efecto del reemplazo de la vegetación nativa de ribera sobre la comunidad de macroinvertebrados bentónicos en arroyos de climas templados, Chile central Replacement effect of riparian native vegetation on benthic macroinvertebrates community in temperate climate streams, Central Chile

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    Gabriela Mancilla


    Full Text Available El aporte de materia orgánica desde la vegetación ribereña es determinante en la estructura y complejidad de los sistemas fluviales; es identificado como el mayor aporte energético en ríos y una fuente importante de alimento para macroinvertebrados en arroyos de cabecera. No obstante, el paisaje ribereño ha sido altamente degradado por actividades humanas, lo que ha afectado la estructura y composición de las comunidades acuáticas. El presente estudio se desarrolló en Chile central (región del Biobío donde se concentra una intensa actividad forestal con especies exóticas. Se seleccionaron ríos de bajo orden (The organic matter from riparian vegetation is determined by the structure and complexity of streams. It presents a higher energetic input to streams as well as important source of food for macroinvertebrates in head streams. In spite of its importance, riparian landscape has been rapidly degraded by human activity, this affects structure and composition of the aquatic community. The present study was made in Central Chile (Biobio Region which has intensive forest activity with exotic species. Small streams were selected (< 3 order, because they are very particularly sensitive to changes in land use. The sites were grouped identified according to native forest land cover larger than 20% (group 1 and smaller than 20% (group 2. Significant differences (p< 0.05 in Plecoptera abundance (p < 0.05 were found between the two groups. Differences in trophic groups were significant for shredders and predators increased and gathering-collectors decreased their abundance, with native cover smaller than 20%. This showed the dependent on allochthonous material. The vegetation cover and community parameters correlations showed that Diversity (W increased with higher percentage of watershed covered by native vegetation and exotic species mix. Results suggest that a buffer conservation area of native riparian vegetation is necessary in streams

  14. Short-Term Effects of the 2008 High-Flow Experiment on Macroinvertebrates in Colorado River Below Glen Canyon Dam, Arizona (United States)

    Rosi-Marshall, Emma J.; Kennedy, Theodore A.; Kincaid, Dustin W.; Cross, Wyatt F.; Kelly, Holly A.W.; Behn, Kathrine A.; White, Tyler; Hall, Robert O.; Baxter, Colden V.


    Glen Canyon Dam has dramatically altered the physical environment (especially discharge regime, water temperatures, and sediment inputs) of the Colorado River. High-flow experiments (HFE) that mimic one aspect of the natural hydrograph (floods) were implemented in 1996, 2004, and 2008. The primary goal of these experiments was to increase the size and total area of sandbar habitats that provide both camping sites for recreational users and create backwaters (areas of stagnant flow in the lee of return-current eddies) that may be important as rearing habitat for native fish. Experimental flows might also positively or negatively alter the rainbow trout (Oncorhynchus mykiss) sport fishery in the clear tailwater reach below Glen Canyon Dam, Ariz., and native fish populations in downstream reaches (for example, endangered humpback chub, Gila cypha) through changes in available food resources. We examined the short-term response of benthic macroinvertebrates to the March 2008 HFE at three sites [river mile 0 (RM 0, 15.7 miles downriver from the dam), RM 62, and RM 225] along the Colorado River downstream from Glen Canyon Dam by sampling immediately before and then 1, 7, 14, and 30 days after the HFE. We selected these sites because of their importance to management; RM 0 has a valuable trout fishery, and RM 62 is the location of the largest population of the endangered humpback chub in the Grand Canyon. In addition to the short-term collection of samples, as part of parallel investigations, we collected 3 years of monthly (quarterly for RM 62) benthic macroinvertebrate samples that included 15 months of post-HFE data for all three sites, but processing of the samples is only complete for one site (RM 0). At RM 0, the HFE caused an immediate 1.75 g AFDM/m2 (expressed as grams ash-free dry mass, or AFDM) reduction of macroinvertebrate biomass that was driven by significant reductions in the biomass of the two dominant taxa in this reach-Potamopyrgus antipodarum (New

  15. Dual fuels: intra-annual variation in the relative importance of benthic and pelagic resources to maintenance, growth and reproduction in a generalist salmonid fish. (United States)

    Hayden, Brian; Harrod, Chris; Kahilainen, Kimmo K


    Ecological systems are often characterized as stable entities. However, basal productivity in most ecosystems varies between seasons, particularly in subarctic and polar areas. How this variability affects higher trophic levels or entire food webs remains largely unknown, especially in these high-latitude regions. We undertook a year-long study of benthic (macroinvertebrate) and pelagic (zooplankton) resource availability, along with short (day/days: stomach content)-, medium (month: liver δ(13)C and δ(15)N isotopes)- and long-term (season: muscle δ(13)C and δ(15)N isotopes) assessments of resource use by a generalist fish, the European whitefish, in a deep, oligotrophic, subarctic lake in northern Europe. Due to the long ice-covered winter period, we expected to find general benthic reliance throughout the year, but also a seasonal importance of zooplankton to the diet, somatic growth and gonadal development of whitefish. Benthic and pelagic resource availability varied between seasons: peak littoral benthic macroinvertebrate density occurred in mid-winter, whereas maximum zooplankton density was observed in summer. Whitefish stomach content revealed a reliance on benthic prey items during winter and pelagic prey in summer. A seasonal shift from benthic to pelagic prey was evident in liver isotope ratios, but muscle isotope ratios indicated a year-round reliance on benthic macroinvertebrates. Whitefish activity levels as well as somatic and gonadal growth all peaked during the summer, coinciding with the zooplankton peak and the warmest water temperature. Stable isotopes of muscle consistently depicted the most important resource, benthic macroinvertebrates, whereas short-term indicators, that is, diet and stable isotopes of liver, revealed the seasonal significance of pelagic zooplankton for somatic growth and gonad development. Seasonal variability in resource availability strongly influences consumer growth and reproduction and may also be important in

  16. Response of macroinvertebrate communities to temporal dynamics of pesticide mixtures: A case study from the Sacramento River watershed, California. (United States)

    Chiu, Ming-Chih; Hunt, Lisa; Resh, Vincent H


    Pesticide pollution from agricultural field run-off or spray drift has been documented to impact river ecosystems worldwide. However, there is limited data on short- and long-term effects of repeated pulses of pesticide mixtures on biotic assemblages in natural systems. We used reported pesticide application data as input to a hydrological fate and transport model (Soil and Water Assessment Tool) to simulate spatiotemporal dynamics of pesticides mixtures in streams on a daily time-step. We then applied regression models to explore the relationship between macroinvertebrate communities and pesticide dynamics in the Sacramento River watershed of California during 2002-2013. We found that both maximum and average pesticide toxic units were important in determining impacts on macroinvertebrates, and that the compositions of macroinvertebrates trended toward taxa having higher resilience and resistance to pesticide exposure, based on the Species at Risk pesticide (SPEARpesticides) index. Results indicate that risk-assessment efforts can be improved by considering both short- and long-term effects of pesticide mixtures on macroinvertebrate community composition.

  17. Aquatic macroinvertebrate responses to native and non-native predators

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    Haddaway N. R.


    Full Text Available Non-native species can profoundly affect native ecosystems through trophic interactions with native species. Native prey may respond differently to non-native versus native predators since they lack prior experience. Here we investigate antipredator responses of two common freshwater macroinvertebrates, Gammarus pulex and Potamopyrgus jenkinsi, to olfactory cues from three predators; sympatric native fish (Gasterosteus aculeatus, sympatric native crayfish (Austropotamobius pallipes, and novel invasive crayfish (Pacifastacus leniusculus. G. pulex responded differently to fish and crayfish; showing enhanced locomotion in response to fish, but a preference for the dark over the light in response to the crayfish. P.jenkinsi showed increased vertical migration in response to all three predator cues relative to controls. These different responses to fish and crayfish are hypothesised to reflect the predators’ differing predation types; benthic for crayfish and pelagic for fish. However, we found no difference in response to native versus invasive crayfish, indicating that prey naiveté is unlikely to drive the impacts of invasive crayfish. The Predator Recognition Continuum Hypothesis proposes that benefits of generalisable predator recognition outweigh costs when predators are diverse. Generalised responses of prey as observed here will be adaptive in the presence of an invader, and may reduce novel predators’ potential impacts.

  18. Variations in benthic macroinvertebratefauna as indicator of land use in the Ken River, central India


    P. Nautiyal; Mishra, A.S.


    Examination of benthic macroinvertebrates in semi-natural, urban and agricultural land use along the highland Ken River in central India reveals a significantly higher density in semi-natural compared with other two landuse. Insects dominate the fauna at semi-natural (90%) and urban locations (93%) compared to agriculture sites (48%) where where annelid share increases to 32%. The semi-natural location characterized by rocky substrate support high relative abundance of Caenidae and Neoepheme...

  19. Structure of a Northwest Atlantic Shelf Macofaurnal Assemblage with Respect to Seasonal Variation in Sediment Nutritional Quality (United States)

    We examined temporal variation in the relationship between benthic macrofaunal assemblage structure and sediment nutritional quality, using core samples taken seasonally from a 232 m deep site in Wilkinson Basin, Gulf of Maine from October 2003 through August 2004. The benthic as...

  20. Influence of bed heterogeneity and habitat type on macroinvertebrate uptake in peri-urban streams

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    The role of geomorphic structure, referred to as physical heterogeneity, and its influence upon the colonization of habitat by macroinvertebrates was analysed in the peri-urban, Twin Streams Catchment, in West Auckland, New Zealand. Using a cross-scalar approach, 4 riffle-run assemblages were analysed in each of 2 River Styles (a confined, low sinuosity, gravel bed river and a partly confined, low sinuosity, bedrock, cobble, and gravel bed river). Each of these 8 locations comprised 2 distinct sampling areas; the upstream zone had a more heterogeneous river bed with a high diversity of physical features and flow, whilst the downstream area had a more homogeneous structure. Microhabitat features sampled at each site included streambed material, bank margins, fine grained organic debris, wood, and boulders. Habitat mosaics and their associated macroinvertebrate relationships followed a semi-predictable but interrupted pattern, supporting the view that river systems are a patchy discontinuum. Homogeneous zones were more frequently characterised by higher proportions of Trichoptera than heterogeneous zones, whilst heterogeneous zones were frequently characterised by Plecoptera and Ephemeroptera. Diversity was maximised when the species pools from heterogeneous and homogeneous sites were combined for any given site. Functional habitats influenced macroinvertebrate assemblages in non-linear and complex ways. Wood and organic debris habitats were associated with high diversity, abundance, and sensitive species whereas streambed habitat was usually associated with low diversity. A diverse range of physical zones that approximates the 'natural range of behaviour' for the given type of stream was considered to provide a more effective platform for rehabilitation planning than emphasising heterogeneity of physical structure in its own right.

  1. Classification and retrieval on macroinvertebrate image databases. (United States)

    Kiranyaz, Serkan; Ince, Turker; Pulkkinen, Jenni; Gabbouj, Moncef; Ärje, Johanna; Kärkkäinen, Salme; Tirronen, Ville; Juhola, Martti; Turpeinen, Tuomas; Meissner, Kristian


    Aquatic ecosystems are continuously threatened by a growing number of human induced changes. Macroinvertebrate biomonitoring is particularly efficient in pinpointing the cause-effect structure between slow and subtle changes and their detrimental consequences in aquatic ecosystems. The greatest obstacle to implementing efficient biomonitoring is currently the cost-intensive human expert taxonomic identification of samples. While there is evidence that automated recognition techniques can match human taxa identification accuracy at greatly reduced costs, so far the development of automated identification techniques for aquatic organisms has been minimal. In this paper, we focus on advancing classification and data retrieval that are instrumental when processing large macroinvertebrate image datasets. To accomplish this for routine biomonitoring, in this paper we shall investigate the feasibility of automated river macroinvertebrate classification and retrieval with high precision. Besides the state-of-the-art classifiers such as Support Vector Machines (SVMs) and Bayesian Classifiers (BCs), the focus is particularly drawn on feed-forward artificial neural networks (ANNs), namely multilayer perceptrons (MLPs) and radial basis function networks (RBFNs). Since both ANN types have been proclaimed superior by different investigations even for the same benchmark problems, we shall first show that the main reason for this ambiguity lies in the static and rather poor comparison methodologies applied in most earlier works. Especially the most common drawback occurs due to the limited evaluation of the ANN performances over just one or few network architecture(s). Therefore, in this study, an extensive evaluation of each classifier performance over an ANN architecture space is performed. The best classifier among all, which is trained over a dataset of river macroinvertebrate specimens, is then used in the MUVIS framework for the efficient search and retrieval of particular

  2. Macroinvertebrates communities associated with the decomposition of Phragmites australis and Fucus vesiculosus in transitional systems (United States)

    Lopes, Marta Lobão; Martins, Patrícia; Rodrigues, Ana Maria; Quintino, Victor


    The decomposition rates of a macrophyte (Phragmites australis) and an alga (Fucus vesiculosus) and the associated macrofauna communities were studied along a full salinity gradient, using the leaf-bag technique and four sampling times (days 3, 7, 15 and 30). A control was set up using an artificial substrate. A subsequent study conducted in the mesohaline part of the salinity gradient also included empty bags as procedure control. The decay rates of the alga and the macrophyte were significantly different, the alga decaying faster, and presented an opposite trend along the salinity gradient, with the faster decay rate for reed in the less saline areas and for the alga in the euhaline part of the gradient. The fauna associated with the decaying and the artificial substrate showed equally well the benthic succession from the marine to the freshwater areas, in all sampling times. Arthropods were dominant in all substrates along the estuarine gradient and replaced by annelids in freshwater. No significant differences were found between the benthic communities associated with P. australis and F. vesiculosus, despite the strong differences in the decay rates, suggesting that these do not seem to be primarily related to the benthic colonizers. Although the organic substrates sustained a more abundant fauna, the benthic communities did not show significant differences between the organic and the artificial substrates, especially at the level of the species composition, suggesting that the macroinvertebrates may colonize both substrates to feed on the biofilm and/or to seek shelter. The strongly impoverished benthic community sampled by the empty bags reinforced this idea.

  3. The role of benthic foraminifera in the benthic nitrogen cycle of the Peruvian oxygen minimum zone

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    N. Glock


    Full Text Available The discovery that foraminifera are able to use nitrate instead of oxygen as energy source for their metabolism has challenged our understanding of nitrogen cycling in the ocean. It was evident before that only prokaryotes and fungi are able to denitrify. Rate estimates of foraminiferal denitrification were very sparse on a regional scale. Here, we present estimates of benthic foraminiferal denitrification rates from six stations at intermediate water depths in and below the Peruvian oxygen minimum zone (OMZ. Foraminiferal denitrification rates were calculated from abundance and assemblage composition of the total living fauna in both, surface and subsurface sediments, as well as from individual species specific denitrification rates. A comparison with total benthic denitrification rates as inferred by biogeochemical models revealed that benthic foraminifera account for the total denitrification on the shelf between 80 and 250 m water depth. They are still important denitrifiers in the centre of the OMZ around 320 m (29–56% of the benthic denitrification but play only a minor role at the lower OMZ boundary and below the OMZ between 465 and 700 m (3–7% of total benthic denitrification. Furthermore, foraminiferal denitrification was compared to the total benthic nitrate loss measured during benthic chamber experiments. Foraminiferal denitrification contributes 1 to 50% to the total nitrate loss across a depth transect from 80 to 700 m, respectively. Flux rate estimates ranged from 0.01 to 1.3 mmol m−2 d−1. Furthermore we show that the amount of nitrate stored in living benthic foraminifera (3 to 705 µmol L−1 can be higher by three orders of magnitude as compared to the ambient pore waters in near surface sediments sustaining an important nitrate reservoir in Peruvian OMZ sediments. The substantial contribution of foraminiferal nitrate respiration to total benthic nitrate loss at the Peruvian margin

  4. The role of benthic foraminifera in the benthic nitrogen cycle of the Peruvian oxygen minimum zone

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    N. Glock


    Full Text Available The discovery that foraminifera are able to use nitrate instead of oxygen as an electron acceptor for respiration has challenged our understanding of nitrogen cycling in the ocean. It was thought before that only prokaryotes and some fungi are able to denitrify. Rate estimates of foraminiferal denitrification have been very sparse and limited to specific regions in the oceans, not comparing stations along a transect of a certain region. Here, we present estimates of benthic foraminiferal denitrification rates from six stations at intermediate water depths in and below the Peruvian oxygen minimum zone (OMZ. Foraminiferal denitrification rates were calculated from abundance and assemblage composition of the total living fauna in both surface and subsurface sediments, as well as from individual species specific denitrification rates. A comparison with total benthic denitrification rates as inferred by biogeochemical models revealed that benthic foraminifera probably account for the total denitrification in shelf sediments between 80 and 250 m water depth. The estimations also imply that foraminifera are still important denitrifiers in the centre of the OMZ around 320 m (29–50% of the benthic denitrification, but play only a minor role at the lower OMZ boundary and below the OMZ between 465 and 700 m (2–6% of total benthic denitrification. Furthermore, foraminiferal denitrification has been compared to the total benthic nitrate loss measured during benthic chamber experiments. The estimated foraminiferal denitrification rates contribute 2 to 46% to the total nitrate loss across a depth transect from 80 to 700 m, respectively. Flux rate estimates range from 0.01 to 1.3 mmol m−2 d−1. Furthermore we show that the amount of nitrate stored in living benthic foraminifera (3 to 3955 μmol L−1 can be higher by three orders of magnitude as compared to the ambient pore waters in near-surface sediments sustaining an important nitrate reservoir in

  5. Landscape composition as a determinant of diversity and functional feeding groups of aquatic macroinvertebrates in southern rivers of the Araucanía, Chile

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    Pablo Fierro


    Full Text Available Changes in land use which directly or indirectly affect freshwater fauna constitute one of the principal anthropic factors which have caused world biological diversity to disappear rapidly during recent decades. This fauna includes aquatic benthic macroinvertebrates, organisms presenting temporal and spatial variation due to a variety of factors, one of which is the diverse food resources available in the rivers. To assess the effect of anthropic activities on this fauna, the distribution, abundance and characterisation of the functional feeding groups of aquatic macroinvertebrates were analysed, together with the physical and chemical variables in the environments of four coastal river basins of southern south-central Chile. A total of 104 taxa of macroinvertebrates were recorded, the principal component of the community being the Diptera (26 taxa. The abundance and richness of taxa were greater in summer and lower in winter. The most abundant species belong to the order Ephemeroptera and Plecoptera. Macroinvertebrates were affected by different land use: stations with less anthropic activity and greater altitude had higher macroinvertebrates abundance, while the lowest abundance was found at the lowest stations. The functional feeding groups which were most abundant spatially and temporally were the collector-gatherers and the shredders. The physical and chemical water quality variables proved to be of exceptional quality in all the stations. These results suggest that policies governing changes in land use in central and southern Chile should take into account the dramatic alterations that these changes impose on the macroinvertebrates community. Policies for biodiversity conservation should therefore focus on these small but important organisms in the north Patagonian region of South America, which is a hotspot of world diversity.

  6. Effects of a triazole fungicide and a pyrethroid insecticide on the decomposition of leaves in the presence or absence of macroinvertebrate shredders. (United States)

    Rasmussen, Jes Jessen; Monberg, Rikke Juul; Baattrup-Pedersen, Annette; Cedergreen, Nina; Wiberg-Larsen, Peter; Strobel, Bjarne; Kronvang, Brian


    Previously, laboratory experiments have revealed that freely diluted azole fungicides potentiate the direct toxic effect of pyrethroid insecticides on Daphnia magna. More ecologically relevant exposure scenarios where pesticides are adsorbed have not been addressed. In this study we exposed beech leaves (Fagus sylvatica) to the azole fungicide propiconazole (50 or 500 μg L(-1)), the pyrethroid insecticide alpha-cypermethrin (0.1 or 1 μg L(-1)) or any combination of the two for 3h. Exposed leaves were transferred to aquaria with or without an assemblage of macroinvertebrate shredders, and we studied treatment effects on rates of microbial leaf decomposition, microbial biomass (using C:N ratio as a surrogate measure) and macroinvertebrate shredding activity during 26 days post-exposure. Microbial leaf decomposition rates were significantly reduced in the propiconazole treatments, and the reduction in microbial activity was significantly correlated with loss of microbial biomass (increased C:N ratio). Macroinvertebrate shredding activity was significantly reduced in the alpha-cypermethrin treatments. In addition, the macroinvertebrate assemblage responded to the propiconazole treatments by increasing their consumption of leaf litter with lower microbial biomass, probably to compensate for the reduced nutritional quality of this leaf litter. We found no interaction between the two pesticides on macroinvertebrate shredding activity, using Independent Action as a reference model. In terms of microbial leaf decomposition rates, however, alpha-cypermethrin acted as an antagonist on propiconazole. Based on these results we emphasise the importance of considering indirect effects of pesticides in the risk assessment of surface water ecosystems.

  7. Taxonomic spectrum of macroinvertebrate communities in Săsar River (NW Romania

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    Oana-Elena MARE ROŞCA


    Full Text Available The following article analyses the taxonomic composition of benthic macroinvertebrates in Săsar river, which flows in the North West of Romania in a highly industrialized area. According to prior studies, increased biological unbalances have been observed due to mining activities, meaning that Săsar river, out of its 31 kilometers from the spring to the flow, has 17 kilometers which are completely downgraded. According to the systematic research done between 2003-2006, 41 taxa were identified. After working with the physical-chemical monitoring data, it was noticed that the low diversity of zoobenthic communities was due to the toxic pollutants from the mining and metallurgic industries.

  8. Effects of an oil spill on leafpack-inhabiting macroinvertebrates in the Chariton river, Missouri (United States)

    Poulton, B.C.; Callahan, E.V.; Hurtubise, R.D.; Mueller, B.G.


    Artificial leaf packs were used to determine the effects of an oil spill on stream macroinvertebrate communities in the Chariton River, Missouri. Plastic mesh leaf retainers with approximately 10 g of leaves from five tree species were deployed at five sites (two upstream of the spill and three downstream) immediately after the spill and one year later. Four macroinvertebrate species dominating the community at upstream sites were virtually eliminated below the spill, including the stonefly Isoperla bilineata, the caddisfly Potamyia flava, the midge Thienemanniella xena, and blackfly larvae (Simulium sp.). Density of collector and shredder functional groups, and number of shredder taxa differed between upstream sites and the two furthest downstream sites during the 1990 sample period (Kruskal-Wallis w/Bonferroni paired comparisons, experiment wise error rate = 0.05). With one exception, no differences between sites were detected in the 1991-1992 sample period, indicating that the benthic community had at least partially recovered from the oil spill after one year. The odds of obtaining a sample with a small abundance of shredders (abundance spill than upstream, and the odds of obtaining a sample with a small abundance of shredders at downstream sites was greater in 1990 than in 1991-1992. A similar pattern was observed in abundance and taxa richness of the collector functional group. No significant differences between the two sampling periods were detected at upstream sites. Observed effects appeared to be associated with oil sorption and substrate coating, creating conditions unsuitable for successful colonization.

  9. Using a Geospatial Model to Relate Fluvial Geomorphology to Macroinvertebrate Habitat in a Prairie River—Part 1: Genus-Level Relationships with Geomorphic Typologies

    Directory of Open Access Journals (Sweden)

    Anna G. N. Meissner


    Full Text Available Modern river ecosystems undergo constant stress from disturbances such as bank stabilization, channelization, dams, and municipal, agricultural, and industrial water use. As these anthropogenic water requirements persist, more efficient methods of characterizing river reaches are essential. Benthic macroinvertebrates are helpful when evaluating fluvial health, because they are often the first group to react to contaminants that can then be transferred through them to other trophic levels. Hence, the purpose of this research is to use a geospatial model to differentiate instream macroinvertebrate habitats, and determine if the model is a viable method for stream evaluation. Through the use of ArcGIS and digital elevation models, the fluvial geomorphology of the Qu’Appelle River in Saskatchewan (SK was assessed. Four geomorphological characteristics of the river were isolated (sinuosity, slope, fractal dimension, and stream width and clustered through Principle Component Analysis (PCA, yielding sets of river reaches with similar geomorphological characteristics, called typologies. These typologies were mapped to form a geospatial model of the river. Macroinvertebrate data were aligned to the locations of the typologies, revealing several relationships with the fluvial geomorphology. A Kruskal-Wallis analysis and post hoc pairwise multiple comparisons were completed with the macroinvertebrate data to pinpoint significant genera, as related to the geospatial model.


    Directory of Open Access Journals (Sweden)

    Alexandre Monkolski, Janet Higuti, Luiz Alberto Vieira, Roger Paulo Mormul e Sidnei Pressinatte Junior


    Full Text Available The pollutant substance poured in the environment causes negative impacts for life forms that inhabit the sources. The biological monitoring of aquatic ecosystems has as objective the evaluation of the quality of water, in function of alterations of the community of macroinvertebrates. Among these communities Benthic is distinguished, because it reflects the state of conservation or degradation of the sources, changing their morphophysiological characteristics and its presence or absence in water. The quality of Papagaios’ river water was evaluated by physical-chemistry analysis and by density of Benthic macroinvertebrates. Four colleting stations from a stretch of the river were analyzed and samples of sediment and water were collected. At 2nd and 3rd stations there are two cold storage rooms installed at the river’s margins, which treat their effluents in stabilizing lagoons. The 4th station receives the ousting directly from a textile after it has passed by a treatment. Results obtained by biological methods indicated the presence of polluting elements in water. The river’s longitudinal gradient showed a typical sucessorial process of macroinvertebrates from polluted environments, with a significant increase in the density of Oligochaeta and Chironidade, organisms that are tolerant to impacts in water. Considering the four stations that were analyzed, the unwished impacts are occurring in three last ones with more intensity.

  11. Influence of seasonal variation on bioassessment of streams using macroinvertebrates

    NARCIS (Netherlands)

    Sporka, F.; Vlek, H.E.; Bulánková, E.; Krno, I.


    The EU Water Framework Directive requires assessment of the ecological quality of running waters using macroinvertebrates. One of the problems of obtaining representative samples of organisms from streams is the choice of sampling date, as the scores obtained from macroinvertebrate indices vary natu

  12. Are macroinvertebrates in high altitude streams affected by oxygen deficiency?

    DEFF Research Database (Denmark)

    Jacobsen, Dean; Rostgaard, S.; Vásconez, J. J.


    conditions. However, this fails to take into account that oxygen solubility declines with decreasing atmospheric pressure, which may be of importance at high altitudes. 2. Based on samples of macroinvertebrate benthos and in situ measurements of respiratory oxygen demand of macroinvertebrates in small...

  13. Characterization of benthic communities and physical habitat in the Stanislaus, Tuolumne, and Merced Rivers, California. (United States)

    Hall, Lenwood W; Killen, William D; Anderson, Ronald D


    The primary goal of this study was to characterize physical habitat and benthic communities (macroinvertebrates) in the Stanislaus, Tuolumne and Merced Rivers in California's San Joaquin Valley in 2003. These rivers have been listed as impaired water bodies (303 (d) list) by the State of California due to the presence of organophosphate (OP) insecticides chlorpyrifos and diazinon, Group A pesticides (i.e., organochlorine pesticides), mercury, or unknown toxicity. Based on 10 instream and riparian physical habitat metrics, total physical habitat scores in the Stanislaus River ranged from 124 to 188 (maximum possible total score is 200). The highest total habitat score was reported at the upstream site. Tuolumne River physical habitat scores ranged from 86 to 167. Various Tuolumne River physical habitat metrics, including total habitat score, increased from downstream to upstream in this river. Merced River physical habitat scores ranged from 121 to 170 with a significant increase in various physical habitat metrics, including total habitat score, reported from downstream to upstream. Channel flow (an instream metric) and bank stability (a riparian metric) were the most important physical habitat metrics influencing the various benthic metrics for all three rivers. Abundance measures of benthic macroinvertebrates (5,100 to 5,400 individuals) were similar among the three rivers in the San Joaquin watershed. Benthic communities in all three rivers were generally dominated by: (1) Baetidae species (mayflies) which are a component of EPT taxa generally considered sensitive to environmental degradation; (2) Chironomidae (midges) which can be either tolerant or sensitive to environmental stressors depending on the species; (3) Ephemerellidae (mayflies) which are considered sensitive to pollution stress; and (4) Naididae (aquatic worms) which are generally considered tolerant to environmental stressors. The presence of 117 taxa in the Stanislaus River, 114 taxa in the

  14. Benthic foraminiferal distribution in surface sediments along continental slope of the southern Okinawa Trough:dependance on water masses and food supply

    Institute of Scientific and Technical Information of China (English)

    向荣; 李铁刚; 杨作升; 阎军; 曹奇原


    Benthic foraminiferal analysis of 29 samples in surface sediments from the southern Oki-nawa Trough is carried out. The results indicate that benthic foraminiferal abundance decreases rapidlywith increasing water depth. Percentage frequencies of agglutinated foraminifera further confirm themodem shallow carbonate lysocline in the southern Okinawa Trough. From continental shelf edge to thebottom of Okinawa Trough, benthic foraminiferal fauna in the surface sediments can be divided into 5assemblages: (1) Continental shelf break assemblage, dominated by Cibicides pseudoungerianus, corre-sponds to subsurface water mass of the Kuroshio Current; (2) upper continental slope assemblage, domi-nated by Cassidulina carinata, Globocassidulina subglobosa, corresponds to intermediate water mass of the Kuroshio Current; (3) intermediate continental slope assemblage, dominated by Uvigerina hispi-da, corresponds to the Okinawa Trough deep water mass above the carbonate lysocline; (4) lower con-tinental slope- trough bottom assemblage, dominated by Pullenia bulloides, Epistominella exigua andCibicidoides hyalinus, corresponds to deep water mass of the Okinawa Trough; and (5) trough bottomagglutinated assemblage, dominated by Rhabdammina spp., Bathysiphon flavidus, corresponds tostrongly dissolved environment of the trough bottom. The benthic foraminiferal fauna in the southemOkinawa Trough are controlled jointly by water masses and food supply. Water temperature, oxygenconcentration and carbonate dissolution of the water masses are important controlling factors especiallyfor the continental shelf break and trough bottom assemblages. The food supply also plays an importantrole in these benthic foraminiferal assemblages along the westem slope of the Okinawa Trough. Both theabundance and the 5 assemblages of benthic foraminifera correspond well to the organic matter supplyalong the continental slope and a lateral transport of TSM (total suspended matter) and POC (particulateorganic

  15. Macroinvertebrate community assembly in pools created during peatland restoration. (United States)

    Brown, Lee E; Ramchunder, Sorain J; Beadle, Jeannie M; Holden, Joseph


    Many degraded ecosystems are subject to restoration attempts, providing new opportunities to unravel the processes of ecological community assembly. Restoration of previously drained northern peatlands, primarily to promote peat and carbon accumulation, has created hundreds of thousands of new open water pools. We assessed the potential benefits of this wetland restoration for aquatic biodiversity, and how communities reassemble, by comparing pool ecosystems in regions of the UK Pennines on intact (never drained) versus restored (blocked drainage-ditches) peatland. We also evaluated the conceptual idea that comparing reference ecosystems in terms of their compositional similarity to null assemblages (and thus the relative importance of stochastic versus deterministic assembly) can guide evaluations of restoration success better than analyses of community composition or diversity. Community composition data highlighted some differences in the macroinvertebrate composition of restored pools compared to undisturbed peatland pools, which could be used to suggest that alternative end-points to restoration were influenced by stochastic processes. However, widely used diversity metrics indicated no differences between undisturbed and restored pools. Novel evaluations of restoration using null models confirmed the similarity of deterministic assembly processes from the national species pool across all pools. Stochastic elements were important drivers of between-pool differences at the regional-scale but the scale of these effects was also similar across most of the pools studied. The amalgamation of assembly theory into ecosystem restoration monitoring allows us to conclude with more certainty that restoration has been successful from an ecological perspective in these systems. Evaluation of these UK findings compared to those from peatlands across Europe and North America further suggests that restoring peatland pools delivers significant benefits for aquatic fauna by

  16. Invasive alien species water hyacinth Eichhornia crassipes as abode for macroinvertebrates in hypertrophic Ramsar Site, Lake Xochimilco, Mexico. (United States)

    Rocha-Ramirez, A; Robles-Valderrama, E; Ramirez-Flores, E


    This paper presents information on the density, diversity and functional feeding groups of macroinvertebrate assemblages associated with water hyacinth in Antiguo Canal Cuemanco, part of Lake Xochimilco in Mexico City. Rare (low frequency and density) and dominant (high frequency and density) taxa prevailed in the assemblages, with the most predominant being Hyalella azteca, Chironomus plumosus and Ischnura denticollis. Nonmetric Multidimensional Scaling confirmed two climatic seasons: warm-rainy and cold-dry; the former with the highest diversity and density of taxa. Canonical Correspondence Analysis showed that conductivity, nitrates and turbidity explained the density variations of taxa. Antiguo Canal Cuemanco waters are spatially homogeneous with the characteristics of hypertrophic shallow lakes, inhabited by scrapers and gathering-collectors. The species found were tolerant to organic pollution.

  17. Aquatic macroinvertebrates of the Jablanica river, Serbia

    Directory of Open Access Journals (Sweden)

    Stefanović Katarina S.


    Full Text Available Research on the community of aquatic macroinvertebrates was carried out during 2005 and 2006 at four sampling sites along the Jablanica River, a right-hand tributary of the Kolubara River. Fifty-seven taxa were recorded in the course of the investigation. The most diverse group was Ephemeroptera, followed by Trichoptera and Plecoptera. Members of the Rhitrogena semicolorata group were the most abundant. Our results could be the basis for evaluation of the influence of damming of the Jablanica River on the status of its water and can serve as a model for studying the influ­ence of hydromorphological degradation of aquatic ecosystems.

  18. Assessment of Ecological Quality of the Tajan River in Iran Using a Multimetric Macroinvertebrate Index and Species Traits (United States)

    Aazami, Jaber; Esmaili Sari, Abbas; Abdoli, Asghar; Sohrabi, Hormoz; Van den Brink, Paul J.


    The objectives of this study were to assess the biological water of the Iranian Tajan River using different metrics, i.e., a Multimetric Macroinvertebrate Index (MMI) and a traits-based method. Twenty-eight physico-chemical parameters, 10 habitat factors, and abundance of macroinvertebrates were obtained for 17 sites. The Shahid-Rajaie dam divides the Tajan River into an up- and downstream part, with different land uses. Eighteen metrics were used to represent four components of ecosystem quality, including tolerance (Hilsenhoff, SIGNAL), diversity (Margalef, Shannon-Wiener, Simpson, and Evenness), abundance (total number of taxa, individuals, Ephemeroptera, Plecoptera, Trichoptera, EPT, and Insects), and composition of assemblages (% Ephemeroptera, % Plecoptera, % Trichoptera, and % EPT Taxa). The integrated MMI was calculated by averaging the obtained scores of all indices. In the next step, we gathered information on 22 biological traits of macroinvertebrates to evaluate whether (group of) traits could be identified that are indicative for specific or general stress. Result showed a decrease in MMI from upstream (very good water quality) to downstream (bad) due to human activities. Industrial activities like pulping and papermaking operations or sand mining in the downstream part had more effects than agriculture and fish ponds in the upstream part. A redundancy analysis biplot showed the variation between the modalities of trait of macroinvertebrates and their correlation with physico-chemical parameters in Tajan River. The findings show that traits can be indicative for different kind of stress but that more effort has to be put in gathering data sets to disentangle the effect of habitat quality, pollution, and the physico-chemical properties of high- versus lowland rivers.

  19. Cascading effects of flow reduction on the benthic invertebrate community in a lowland river

    DEFF Research Database (Denmark)

    Graeber, Daniel; Pusch, Martin T.; Lorenz, Stefan;


    on dissolved oxygen concentrations (DO) have not yet received much attention. We compared the macroinvertebrate composition between reference conditions and a situation after several years of discharge reduction in the Spree River (Brandenburg, Germany). Community composition shifted from rheophilic species...... concentration minima of less than 5 mg l−1 which prevailed 74% of the days in summer. This depletion of DO after flow reduction presumably caused the observed species turnover. Hence, flow reduction in lowland rivers may not only directly impair the ecological functions provided by benthic macroinvertebrates...... to species indifferent to flow conditions. Filter feeders were partially replaced by collector/gatherers, which likely reduces the retention of organic matter, and thus the self-purification capacity of the river section. These shifts were associated with low discharge during summer, cascading into daily DO...

  20. Affects and assemblages

    DEFF Research Database (Denmark)

    Samson, Kristine

    and cultural geopgraphy. On this backdrop the paper states that affects and assemblages could serve as key notions for the reassembling the aesthetics of urban space. Thus, the paper suggest a less formal understanding of urban space and aesthetics, proposing an understanding of aesthetics......Affects and assemblages are Deleuzian Guattarian notions related to aesthetics and spatial territories. In recent urban geography and urban studies these notions are increasingly gaining more impact (Amin & Thrift 2002, Pile 2008, Farías & Bender 2010, Andersen & Harrison 2010, Thrift 2008). What...... happens to aesthetics and how does it change the existing social and geographical understanding of urban space? The paper sets out to reintroduce aesthetical aspects of affects and assemblages in relation to urban space and urban planning. It presupposes urban space as a continuous state of becoming where...

  1. Experimental effects of grazers on autotrophic species assemblages across a nitrate gradient in Florida springs (United States)

    Springs face accelerated degradation of ecosystem structure, namely in the form of autotrophic species assemblage shifts from submerged vascular macrophytes to benthic filamentous algae. Increasing nitrate concentrations have been cited as a primary driver of this shift and numeric nutrient criteria...

  2. The surveillant assemblage. (United States)

    Haggerty, K D; Ericson, R V


    George Orwell's 'Big Brother' and Michel Foucault's 'panopticon' have dominated discussion of contemporary developments in surveillance. While such metaphors draw our attention to important attributes of surveillance, they also miss some recent dynamics in its operation. The work of Gilles Deleuze and Felix Guattari is used to analyse the convergence of once discrete surveillance systems. The resultant 'surveillant assemblage' operates by abstracting human bodies from their territorial settings, and separating them into a series of discrete flows. These flows are then reassembled in different locations as discrete and virtual 'data doubles'. The surveillant assemblage transforms the purposes of surveillance and the hierarchies of surveillance, as well as the institution of privacy.

  3. Macroinvertebrates associated with bryophyta in a first-order Atlantic Forest stream

    Directory of Open Access Journals (Sweden)

    Beatriz F. J. V. Rosa


    Full Text Available This study describes the composition and structure of the benthic community associated with bryophytes in a first-order stream, located in a biological reserve of the Atlantic Forest, during two seasons. During three months of the dry season of 2007 and three months of the rainy season of 2008, samples of bryophytes attached to stones were collected randomly, along a 100 m stream reach. The structure of the community was analyzed through the mean density of individuals, Shannon's diversity index, Pielou's evenness, family richness, dominance index, and the percentage of Ephemeroptera, Plecoptera and Trichoptera (% EPT. Chironomidae larvae were dominant in the two periods of study, followed by Ceratopogonidae in the rainy season, and Naididae in the dry season. The orders EPT contributed 14 families. The results showed that bryophytes constitute suitable habitat which is able to shelter an abundant and diversified benthic fauna in a small extension of the stream. This habitat provides refuge during spates, and thus minimizes downstream transport of the macroinvertebrate fauna.

  4. Cumulative impacts of aggregate extraction on seabed macro-invertebrate communities in an area off the east coast of the United Kingdom (United States)

    Cooper, Keith; Boyd, Siân; Aldridge, John; Rees, Hubert


    This study investigates whether there is any evidence of a large-scale cumulative impact on benthic macro-invertebrate communities as a result of the multiple sites of aggregate extraction located off Great Yarmouth in the southern North Sea. Forty 0.1 m 2 Hamon grab samples were collected from across the region, both within and beyond the extraction area, and analysed for macrofauna and sediment particle size distribution in order to produce a regional description of the status of the seabed environment. In addition, the data were analysed in relation to the area of seabed impacted by dredging over the period 1993-1998. Areas subject to 'direct' impacts were determined through reference to annual electronic records of dredging activity and this information was then used to model the likely extent of areas potentially subject to 'indirect' ecological and geophysical impact. Results showed the study area to be characterised by sands in the northern half of the survey area, and sandy gravels in the south. The low diversity communities found across much of the survey area were typical of mobile sandy sediments. However, stations located in the southern half and northern extreme of the survey area tended to support higher numbers of species and individuals. This may be due to marginally enhanced stability arising from the higher proportion of gravel found in samples to the south of the extraction licenses and to the presence of Sabellaria spinulosa reef in the north. Analysis of data in relation to areas of predicted dredging impact revealed proportionally less gravel and more sand within the 'direct' impact zone, compared to the 'indirect' impact zone. Whilst multivariate analyses of macrofaunal data did not clearly discriminate between dredging impact zones, a comparison of univariate measures revealed significantly lower numbers of species and individuals in areas which have been subject to 'direct' dredging impacts in comparison with 'reference' areas. This

  5. Application of “taxocene surrogation” and “taxonomic sufficiency” concepts to fish farming environmental monitoring. Comparison of BOPA index versus polychaete assemblage structure


    Aguado Giménez, Felipe; Gairin Deulofeu, Joan Ignasi; Martinez-Garcia, Elena; Fernandez-Gonzalez, Victoria; Ballester-Moltó, Mateo; Cerezo-Valverde, Jesús; Sanchez-Jerez, Pablo


    “Taxocene surrogation” and “taxonomic sufficiency” concepts were applied to the monitoring of soft bottoms macrobenthic assemblages influenced by fish farming following two approaches. Polychaete assemblage evaluation through multivariate analysis and the benthic index BOPA were compared. Six fish farms along the Spanish Mediterranean coast were monitored. Polychaete assemblage provided a suitable picture of the impact gradient, being correlated with total free sulphides. BOPA did not support...

  6. Assemblages of Patient Safety

    DEFF Research Database (Denmark)

    Balatsas Lekkas, Angelos


    This thesis identifies how design processes emerge during the use of devices in healthcare, by attending to assemblages where contingencies of risk and harm co-exist with the contribution of healthcare professionals to the safe care of patients. With support from the field of Science and Technology...

  7. Crab death assemblages from Laguna Madre and vicinity, Texas

    Energy Technology Data Exchange (ETDEWEB)

    Plotnick, R.E.; McCarroll, S. (Univ. of Illinois, Chicago (USA)); Powell, E. (Texas A M Univ., College Station (USA))


    Crabs are a major component of modern marine ecosystems, but are only rarely described in fossil assemblages. Studies of brachyuran taphonomy have examined either the fossil end-products of the taphonomic process or the very earliest stages of decay and decomposition. The next logical step is the analysis of modern crab death assemblages; i.e., studies that examine taphonomic loss in areas where the composition of the living assemblage is known. The authors studied crab death assemblages in shallow water sediments at several localities in an near Laguna Madre, Texas. Nearly every sample examined contained some crab remains, most commonly in the form of isolated claws (dactyl and propodus). A crab fauna associated with a buried grass bed contained abundant remains of the xanthid crab Dyspanopeus texanus, including carapaces, chelipeds, and thoraxes, as well as fragments of the portunid Callinectes sapidus and the majiid Libinia dubia. Crab remains may be an overlooked portion of many preserved benthic assemblages, both in recent and modern sediments.

  8. Effects of reef proximity on the structure of fish assemblages of unconsolidated substrata.

    Directory of Open Access Journals (Sweden)

    Arthur L Schultz

    Full Text Available Fish assemblages of unconsolidated sedimentary habitats on continental shelves are poorly described when compared to those of hard substrata. This lack of data restricts the objective management of these extensive benthic habitats. In the context of protecting representative areas of all community types, one important question is the nature of the transition from reefal to sedimentary fish assemblages. We addressed this question using Baited Remote Underwater Videos (BRUVs to assess fish assemblages of sedimentary habitats at six distances from rocky reefs (0, 25, 50, 100, 200, and 400 m at four sites in subtropical eastern Australia. Distance from reef was important in determining fish assemblage structure, and there was no overlap between reef sites and sedimentary sites 400 m from reef. While there was a gradient in assemblage structure at intermediate distances, this was not consistent across sites. All sites, however, supported a mixed 'halo' assemblage comprising both reef and sediment species at sampling stations close to reef. BRUVs used in conjunction with high-resolution bathymetric and backscatter spatial data can resolve differences in assemblage structure at small spatial scales (10s to 100s of metres, and has further application in unconsolidated habitats. Unless a 'reef halo' assemblage is being examined, a minimum of 200 m but preferably 400 m distance from any hard substrate is recommended when designing broader-scale assessments of fish assemblages of sedimentary habitats.

  9. Epi-benthic megafaunal zonation across an oxygen minimum zone at the Indian continental margin

    Digital Repository Service at National Institute of Oceanography (India)

    Hunter, W.R.; Oguri, K.; Kitazato, H.; Ansari, Z.A.; Witte, U.

    changes upon the epi-benthic megafaunal assemblage was investigated by video survey at six stations spanning the OMZ core (540 m), lower boundary (800–1100 m) and below the OMZ (2000 m), between September and November 2008. Structural changes...


    Using reduncancy (RDA) and canonical correlation analysis (CCA) we assessed relationships between chemical and physical characteristics and periphyton at 105 stream sites sampled by REMAP in the mineral belt of the southern Rockies ecoregion in Colorado. We contrasted results ob...

  11. Assessing the importance of alien macro-Crustacea (Malacostraca) within macroinvertebrate assemblages in Belgian coastal harbours (United States)

    Boets, Pieter; Lock, Koen; Goethals, Peter L. M.


    Harbours, which are often characterised by anthropogenic stress in combination with intensive international ship traffic, tend to be very susceptible to aquatic invasions. Since alien macrocrustaceans are known to be very successful across many European waters, a study was made on their distribution and impact in the four Belgian coastal harbours (Nieuwpoort, Ostend, Blankenberge and Zeebrugge). Biological and physical-chemical data were gathered at 43 sampling sites distributed along a salinity gradient in the four harbours. One-fourth of all crustacean species recorded were alien and represented on average 30% of the total macrocrustacean abundance and 65% of the total macrocrustacean biomass. The large share of alien crustaceans in the total macrocrustacean biomass was mainly due to several large alien crab species. Most alien species were found in the oligohaline zone, whereas the number of indigenous species slightly increased with increasing salinity. The low number of indigenous species present at low salinities was probably not only caused by salinity, but also by the lower water quality in this salinity range. Based on the site-specific biocontamination index (SBCI), which was used to assess the ecological water quality, the harbour of Nieuwpoort and Ostend scored best and were classified as good, indicating the limited abundance and the low number of alien macrocrustaceans. Sampling locations situated more inland generally had a higher SBCI and a lower ecological water quality. Zeebrugge and Blankenberge were characterised by a severe biocontamination. For Zeebrugge, this is probably related to the intensive transcontinental commercial ship traffic, whereas for Blankenberge, this could be due to introduction of alien species via recreational crafts or due to its geographical location in the proximity of Zeebrugge. Consistent monitoring of estuarine regions and harbours, which are seen as hotspots for introductions, could help in understanding and predicting the impact of alien species on native biota.

  12. The importance of spatial variation of benthic invertebrates for the ecological assessment of European lakes

    DEFF Research Database (Denmark)

    Solimini, Angelo G.; Sandin, Leif Leonard


    at multiple spatial scales needs to be assessed and efficiently quantified, in order to set up reliable assessment tools of ecological status. Driven by the research activity carried out within the European project Wiser (Water bodies in Europe: Integrative Systems to assess Ecological status and Recovery......Lake assessment systems based on benthic macroinvertebrates critically depend on the amount of spatial variation of organisms within and between lakes. Investigators need to distinguish between community changes that are related to human pressures and those that are caused by inherent natural...

  13. Altitudinal distribution limits of aquatic macroinvertebrates

    DEFF Research Database (Denmark)

    Madsen, Philip B.; Morabowen, Andrés; Andino, Patricio


    altitudinal patterns in population densities, (ii) transplants of the five taxa upstream of their natural altitudinal limit to test the short-term (14days) effect on survival, and (iii) in situ experiments of locomotory activity as a proxy for animal response to relatively small differences in temperature (5...... relatively small differences in temperature and oxygen may produce effects explaining ecological patterns, and depending on the taxon, either water temperature or oxygen saturation, without clear interacting effects, are important drivers of altitudinal limits.......1. Temperature and oxygen are recognised as the main drivers of altitudinal limits of species distributions. However, the two factors are linked, and both decrease with altitude, why their effects are difficult to disentangle. 2. This was experimentally addressed using aquatic macroinvertebrates...

  14. Deep-sea benthic foraminiferal record of the paleoceanography in the southern Okinawa Trough over the last 20 000 years

    Institute of Scientific and Technical Information of China (English)

    翦知湣; 陈荣华; 李保华


    Quantitative analyses have been carried out on benthic foraminifera from 66 samples of Core 255 in the southern Okinawa Trough, in combination with the stable isotopic analyses of planktonic and benthic foraminifera and AMS 14C dating, in order to reconstruct the history of change under deep water conditions and surface paleoproduclivity over the last 20 000 years. The variations in the ratio of agglutinants in benthic foraminiferal fauna and the ratio of fragments in planktonic foraminifera] fauna indicate higher carbonate dissolution during the postglacial stage than during the glacial stage. The distribution of species and the results of Q-mode factor analysis show that there are three distinctly different benthic foraminiferal assemblages during the glacial, deglacial and postglacial stages in the Okinawa Trough over the last 20000 years: the glacial Bulimina aculeata assemblage (especially the dominant species Uvigerina pereyrina) is associated with high surface primary productivity and organic mat

  15. Fashion, Mediations & Method Assemblages

    DEFF Research Database (Denmark)

    Sommerlund, Julie; Jespersen, Astrid Pernille

    of handling multiple, fluid realities with multiple, fluid methods. Empirically, the paper works with mediation in fashion - that is efforts the active shaping of relations between producer and consumer through communication, marketing and PR. Fashion mediation is by no means simple, but organise complex...... Modern. New York, Harvester-Wheatsheaf. Law, J. (2004). After Method - mess in social science research. London and New York, Routledge......., it is an important ambition of this paper to go into a methodological discussion of how "that which effectively happens" can be approached. To this end, the paper will combine Hennion's term of the "mediator" with John Laws methodological term of "method assemblages". Method assemblages is a suggested as a way...

  16. FCJ-177 Television Assemblages

    Directory of Open Access Journals (Sweden)

    Teresa Rizzo


    Full Text Available Television has become a multiplatform medium that houses content on a number of different sites and devices that encourage new forms of engagement. This new digital environment has transformed television from a closed system, where programmes are transmitted to a television set for viewers to tune into, to an open system that produces new television connections and configurations. Drawing on the work of Deleuze and Guattari, Latour and current media theorists, this essay turns to the concept of assemblages for theorising this new interactive multiplatform television environment. Thinking about multiplatform television through the concept of assemblages offers a means of exploring how television devices, texts and media are reconfigured or modified so as to display new functionalities and capacities. It also enables us to consider the way television culture can be deterritorialised and reterritorialised through new connections and in doing so introduce new qualities such as interactivity and reciprocal determination.

  17. Biodiversity in Benthic Ecology

    DEFF Research Database (Denmark)

    Friberg, Nikolai; Carl, J. D.

    Foreword: This proceeding is based on a set of papers presented at the second Nordic Benthological Meeting held in Silkeborg, November 13-14, 1997. The main theme of the meeting was biodiversity in benthic ecology and the majority of contributions touch on this subject. In addition, the proceeding...

  18. Modern benthic foraminifer distribution in the Amerasian Basin, Arctic Ocean (United States)

    Ishman, S.E.; Foley, K.M.


    A total of 38 box cores were collected from the Amerasian Basin, Arctic Ocean during the U.S. Geological Survey 1992 (PI92-AR) and 1993 (PI93-AR) Arctic Cruises aboard the U.S. Coast Guard Icebreaker Polar Star. In addition, the cruises collected geophysical data, piston cores and hydrographic data to address the geologic and oceanographic history of the western Arctic Ocean. This paper reports the results of the quantitative analyses of benthic foraminifer distribution data of the total (live + dead) assemblages derived from 22 box core-top samples. The results show that a distinct depth distribution of three dominant benthic foraminifer assemblages, the Textularia spp. - Spiroplectammina biformis, Cassidulina teretis and Oridorsalis tener - Eponides tumidulus Biofacies are strongly controlled by the dominant water masses within the Canada Basin: the Arctic Surface Water, Arctic Intermediate Water and Canada Basin Deep Water. The faunal distributions and their oceanographic associations in the Canada Basin are consistent with observations of benthic foraminifer distributions from other regions within the Arctic Ocean.

  19. Laboratory analyses of the potential toxicity of sediment-associated polydimethylsiloxane to benthic macroinvertebrates

    NARCIS (Netherlands)

    Henry, K.S.; Wieland, W.H.; Powell, D.E.; Giesy, J.P.


    Polydimethylsiloxane (PDMS) is widely used in a number of industrial processes and consumer products that result in down-the-drain disposal. The log p value for the PDMS used in the present study was 10, and the vapor pressure and water solubility values were below detection limits. These physicoche

  20. Benthic macroinvertebrate community structure and distribution in the Ayeyarwady continental shelf, Andaman Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Ansari Z.A.; Furtado, R.; Badesab, S.; Mehta, P.; Thwin, S.

    , biomass and species diversity of macrobenthos was more in the inshore waters than in the offshore areas of Malaysia and Gulf of Thailand. As indicated earlier, a significant amount of the variation in faunal abundances, not unexpectedly, is a function... in the present study. It was comparable to the one reported from coastal waters of Malaysia9, but higher than those of South China Sea10, Andaman sea16 and Bay of Bengal17. This could be related to differences in sampling methods. The trends in the abundance...

  1. Choosing the best non-parametric richness estimator for benthic macroinvertebrates databases

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    Carola V. BASUALDO


    Full Text Available Los estimadores no paramétricos permiten comparar la riqueza estimada de conjuntos de datos de origen diverso. Empero, como su comportamiento depende de la distribución de abundancia del conjunto de datos, la preferencia por alguno representa una decisión difícil. Este trabajo rescata algunos criterios presentes en la literatura para elegir el estimador más adecuado para macroinvertebrados bentónicos de ríos y ofrece algunas herramientas para su aplicación. Cuatro estimadores de incidencia y dos de abundancia se aplicaron a un inventario regional a nivel de familia y género. Para su evaluación se consideró: el tamaño de submuestra para estimar la riqueza observada, la constancia de ese tamaño de submuestra, la ausencia de comportamiento errático y la similitud en la forma de la curva entre los distintos conjuntos de datos. Entre los estimadores de incidencia, el mejor fue Jack1; entre los de abundancia, ACE para muestras de baja riqueza y Chao1, para las de alta riqueza. La forma uniforme de las curvas permitió describir secuencias generales de comportamiento, que pueden utilizarse como referencia para comparar curvas de pequeñas muestras e inferir su comportamiento –y riqueza– probable, si la muestra fuera mayor. Estos resultados pueden ser muy útiles para la gestión ambiental y actualizan el estado del conocimiento regional de macroinvertebrados.

  2. Sediment Burial Intolerance of Marine Macroinvertebrates


    Hendrick, Vicki J.; Hutchison, Zoë L.; Last, Kim S.


    The marine environment contains suspended particulate matter which originates from natural and anthropogenic sources. Settlement of this material can leave benthic organisms susceptible to smothering, especially if burial is sudden i.e. following storms or activities such as dredging. Their survival will depend on their tolerance to, and their ability to escape from burial. Here we present data from a multi-factorial experiment measuring burial responses incorporating duration, sediment fract...

  3. Depth-related response of macroinvertebrates to the reversal of eutrophication in a Mediterranean lake: Implications for ecological assessment. (United States)

    Bazzanti, Marcello; Mastrantuono, Luciana; Pilotto, Francesca


    A better management of nutrient inflows into lakes has led to an improvement in their conditions (i.e. reversal of eutrophication) and the effects of this on macroinvertebrate communities that inhabit different lake-depth zones is largely unknown. This paper reports a comparison of macroinvertebrate communities living in the eulittoral, infralittoral and sublittoral/profundal zones of Lake Nemi (Central Italy) before and after its natural recovery from eutrophication following the deviation of domestic wastewater. The infralittoral zone responded more rapidly than the other two depth-zones to the improved ecological conditions, as shown by larger differences in community composition between the two periods. In the eulittoral sand, the combined effects of hydromorphological pressures and reversal of eutrophication hindered the biotic response. In the eulittoral and infralittoral zones, typical taxa of mesotrophic waters appeared or increased their abundances after the eutrophication reversal. Benthic invertebrate response was slower in the sublittoral/profundal zone due to deoxygenation that continued to prevail in the deepest area of the lake during summer. However, both tolerant and more sensitive taxa were collected there for the first time. After the reversal of eutrophication, the percentage of molluscan+large crustaceans increased in the infralittoral zone, whereas the oligochaete/chironomid ratio decreased in both sublittoral/profundal and infralittoral zones. Functional feeding metrics (percentages of filter-feeders, collector-gatherers, miners and scrapers/grazers) differently tracked the reversal of eutrophication in the three depth-zones probably according to the effects of the reduction of nutrients on food-web structure influencing macroinvertebrates. Biological Monitoring Working Party (BMWP) and the Average Score Per Taxon (ASPT) seemed to respond to eutrophication reversal only in the sublittoral/profundal zone, where deoxygenation plays a major role

  4. Guam Community Coral Reef Monitoring Program, Macroinvertebrate Training Surveys in Guam in 2012 (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Guam community members gathered macroinvertebrate within a 25-meter x 2-meter belt transect. Members identified macroinvertebrates to species (when possible),...

  5. Guam Community Coral Reef Monitoring Program, Macroinvertebrate Surveys in Guam in 2013 (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Guam community members gathered macroinvertebrate within a 25-meter x 2-meter belt transect. Members identified macroinvertebrates to species (when possible),...

  6. Habitat specialization in tropical continental shelf demersal fish assemblages.

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    Ben M Fitzpatrick

    Full Text Available The implications of shallow water impacts such as fishing and climate change on fish assemblages are generally considered in isolation from the distribution and abundance of these fish assemblages in adjacent deeper waters. We investigate the abundance and length of demersal fish assemblages across a section of tropical continental shelf at Ningaloo Reef, Western Australia, to identify fish and fish habitat relationships across steep gradients in depth and in different benthic habitat types. The assemblage composition of demersal fish were assessed from baited remote underwater stereo-video samples (n = 304 collected from 16 depth and habitat combinations. Samples were collected across a depth range poorly represented in the literature from the fringing reef lagoon (1-10 m depth, down the fore reef slope to the reef base (10-30 m depth then across the adjacent continental shelf (30-110 m depth. Multivariate analyses showed that there were distinctive fish assemblages and different sized fish were associated with each habitat/depth category. Species richness, MaxN and diversity declined with depth, while average length and trophic level increased. The assemblage structure, diversity, size and trophic structure of demersal fishes changes from shallow inshore habitats to deeper water habitats. More habitat specialists (unique species per habitat/depth category were associated with the reef slope and reef base than other habitats, but offshore sponge-dominated habitats and inshore coral-dominated reef also supported unique species. This suggests that marine protected areas in shallow coral-dominated reef habitats may not adequately protect those species whose depth distribution extends beyond shallow habitats, or other significant elements of demersal fish biodiversity. The ontogenetic habitat partitioning which is characteristic of many species, suggests that to maintain entire species life histories it is necessary to protect corridors of

  7. Habitat specialization in tropical continental shelf demersal fish assemblages. (United States)

    Fitzpatrick, Ben M; Harvey, Euan S; Heyward, Andrew J; Twiggs, Emily J; Colquhoun, Jamie


    The implications of shallow water impacts such as fishing and climate change on fish assemblages are generally considered in isolation from the distribution and abundance of these fish assemblages in adjacent deeper waters. We investigate the abundance and length of demersal fish assemblages across a section of tropical continental shelf at Ningaloo Reef, Western Australia, to identify fish and fish habitat relationships across steep gradients in depth and in different benthic habitat types. The assemblage composition of demersal fish were assessed from baited remote underwater stereo-video samples (n = 304) collected from 16 depth and habitat combinations. Samples were collected across a depth range poorly represented in the literature from the fringing reef lagoon (1-10 m depth), down the fore reef slope to the reef base (10-30 m depth) then across the adjacent continental shelf (30-110 m depth). Multivariate analyses showed that there were distinctive fish assemblages and different sized fish were associated with each habitat/depth category. Species richness, MaxN and diversity declined with depth, while average length and trophic level increased. The assemblage structure, diversity, size and trophic structure of demersal fishes changes from shallow inshore habitats to deeper water habitats. More habitat specialists (unique species per habitat/depth category) were associated with the reef slope and reef base than other habitats, but offshore sponge-dominated habitats and inshore coral-dominated reef also supported unique species. This suggests that marine protected areas in shallow coral-dominated reef habitats may not adequately protect those species whose depth distribution extends beyond shallow habitats, or other significant elements of demersal fish biodiversity. The ontogenetic habitat partitioning which is characteristic of many species, suggests that to maintain entire species life histories it is necessary to protect corridors of connected habitats

  8. Abundance and diversity of aquatic macroinvertebrate communities in lakes exposed to Chernobyl-derived ionising radiation

    Energy Technology Data Exchange (ETDEWEB)

    Murphy, J.F. [NERC Centre for Ecology and Hydrology, Wallingford, Oxfordshire, OX10 8BB (United Kingdom); Nagorskaya, L.L. [Institute of Zoology NAS Belarus, 27, Academicheskaya st., 220072, Minsk (Belarus); Smith, J.T., E-mail: [School of Earth and Environmental Sciences, University of Portsmouth, Burnaby Bldg, Burnaby Road, Portsmouth PO1 3QL (United Kingdom)


    Littoral (lake shore) macroinvertebrate communities were studied in eight natural lakes affected by fallout from the Chernobyl accident. The lakes spanned a range in {sup 137}Cs contamination from 100 to 15500 kBq m{sup -2} and estimated external dose rates ranged from 0.13 to 30.7 {mu}Gy h{sup -1}. General linear models were used to assess whether abundance of individuals, taxon richness, Berger-Parker dominance and Shannon-Wiener diversity varied across the lakes. Step-wise multiple regressions were used to relate variation in total abundance, taxon richness, Berger-Parker dominance, Shannon-Wiener diversity, taxon richness within major groups of macroinvertebrates and abundance of the more common individual taxa to the measured environmental characteristics (conductivity, pH, total hardness and phosphate; lake area, lake maximum depth and total external dose) of the lakes. No evidence was found in this study that the ecological status of lake communities has been influenced by radioactive contamination from the Chernobyl accident. Indeed, the most contaminated lake, Glubokoye, contained the highest richness of aquatic invertebrates. Taxon richness in the eight study lakes varied from 22 (Svyatskoe no. 7) to 42 (Glubokoye) which spans a range typical for uncontaminated lakes in the region. Since {sup 90}Sr is readily-absorbed by Mollusca, estimated dose rates to this group exceeded those for other invertebrate groups in two lakes (Perstok and Glubokoye). However this study found no association between mollusc diversity or abundance of individual snail species and variation between lakes in the external radiation dose. Indeed Glubokoye, the lake most contaminated by {sup 90}Sr, had the highest richness of freshwater snails per sample (an average of 8.9 taxa per sample). - Highlights: > We studied the effect of radiation on macroinvertebrates in Chernobyl affected lakes. > Abundance, taxon richness, Berger-Parker dominance, Shannon-Wiener diversity evaluated. > No

  9. A comparison of macroinvertebrate and habitat methods of data collection in the Little Colorado River Watershed, Arizona 2007 (United States)

    Spindler, Patrice; Paretti, Nick V.


    attribute for both datasets in classifying IBI scores into assessment categories. Habitat measurements generated from EMAP and ADEQ methods were also significantly correlated; 13 of 16 habitat measures were significantly correlated (pflow conditions, as well as canopy cover as important combinations of habitat attributes affecting both IBI scores. These results indicate that similar habitat measures can be obtained using two different field sampling protocols. In addition, similar combinations of these habitat parameters were important to macroinvertebrate community condition in multivariate analyses of both ADEQ and EMAP datasets. These results indicate the two sampling methods for macroinvertebrates and habitat data were very similar in terms of bioassessment results and stressors. While the bioassessment category was not identical for all sites, overall the assessments were significantly correlated, providing similar bioassessment results for the cold water streams used in this study. The findings of this study indicate that ADEQ can utilize either a riffle-based sampling methodology or a multi-habitat sampling approach in cold water streams as both yield similar results relative to the macroinvertebrate assemblage. These results will allow for use of either macroinvertebrate dataset to determine water quality standards compliance with the ADEQ Indexes of Biological Integrity, for which threshold values were just recently placed into the Arizona Surface Water Quality Standards. While this survey did not include warm water desert streams of Arizona, we would predict that EMAP and ADEQ sampling methodologies would provide similar bioassessment results and would not be significantly different, as we have found that the percent riffle habitat in cold and warm water perennial, wadeable streams is not significantly different. However, a comparison study of sampling methodologies in warm water streams should be conducted to confirm the predicted similarity of bioassessment

  10. Headwater streams and forest management: does ecoregional context influence logging effects on benthic communities? (United States)

    Medhurst, R. Bruce; Wipfli, Mark S.; Binckley, Chris; Polivka, Karl; Hessburg, Paul F.; Salter, R. Brion


    Effects of forest management on stream communities have been widely documented, but the role that climate plays in the disturbance outcomes is not understood. In order to determine whether the effect of disturbance from forest management on headwater stream communities varies by climate, we evaluated benthic macroinvertebrate communities in 24 headwater streams that differed in forest management (logged-roaded vs. unlogged-unroaded, hereafter logged and unlogged) within two ecological sub-regions (wet versus dry) within the eastern Cascade Range, Washington, USA. In both ecoregions, total macroinvertebrate density was highest at logged sites (P = 0.001) with gathering-collectors and shredders dominating. Total taxonomic richness and diversity did not differ between ecoregions or forest management types. Shredder densities were positively correlated with total deciduous and Sitka alder (Alnus sinuata) riparian cover. Further, differences in shredder density between logged and unlogged sites were greater in the wet ecoregion (logging × ecoregion interaction; P = 0.006) suggesting that differences in post-logging forest succession between ecoregions were responsible for differences in shredder abundance. Headwater stream benthic community structure was influenced by logging and regional differences in climate. Future development of ecoregional classification models at the subbasin scale, and use of functional metrics in addition to structural metrics, may allow for more accurate assessments of anthropogenic disturbances in mountainous regions where mosaics of localized differences in climate are common.

  11. Benthic foraminifers on the continental shelf and upper slope, Russian River area, northern California ( USA). (United States)

    Quinterno, P.J.; Gardner, J.V.


    We analyzed benthic foraminifers from 71 surface samples collected from the sea floor of the continental margin. One hundred and six different taxa were identified, and Q-mode factor analysis was used to identify assemblages. Six foraminiferal assemblage factors explain 94% of the variation in the data matrix. The Inner Shelf Assemblage is characterized by Trichohyalus ornatissima, Rotalia columbiensis, Cassidulina limbata, Cibicides fletcheri, Elphidiella hannai and Elphidium sp. 1 and occupies water depths less than 50 m. The Middle Shelf Assemblage is characterized by Nonionella basispinata, Elphidium excavatum and Florilus labradoricus and occupies water depths between 50 and 90 m. A Middle Shelf to Upper Bathyal Assemblage is characterized by Uvigerina juncea, Globobulimina spp. and Nonionella basispinata and occupies depths between about 90 and 450 m. Two overlapping assemblages make up the Upper Middle Bathyal Assemblage and are most abundant between water depths of 500 and 1300 m. They are associated with low- oxygen conditions. The Mid-Bathyal Assemblage is dominated by Uvigerina proboscidea and occurs on the slope at water depths ranging from 1200 to 2500 m. -from Authors

  12. Long-Term Impacts on Macroinvertebrates Downstream of Reclaimed Mountaintop Mining Valley Fills in Central Appalachia (United States)

    Pond, Gregory J.; Passmore, Margaret E.; Pointon, Nancy D.; Felbinger, John K.; Walker, Craig A.; Krock, Kelly J. G.; Fulton, Jennifer B.; Nash, Whitney L.


    Recent studies have documented adverse effects to biological communities downstream of mountaintop coal mining and valley fills (VF), but few data exist on the longevity of these impacts. We sampled 15 headwater streams with VFs reclaimed 11-33 years prior to 2011 and sampled seven local reference sites that had no VFs. We collected chemical, habitat, and benthic macroinvertebrate data in April 2011; additional chemical samples were collected in September 2011. To assess ecological condition, we compared VF and reference abiotic and biotic data using: (1) ordination to detect multivariate differences, (2) benthic indices (a multimetric index and an observed/expected predictive model) calibrated to state reference conditions to detect impairment, and (3) correlation and regression analysis to detect relationships between biotic and abiotic data. Although VF sites had good instream habitat, nearly 90 % of these streams exhibited biological impairment. VF sites with higher index scores were co-located near unaffected tributaries; we suggest that these tributaries were sources of sensitive taxa as drifting colonists. There were clear losses of expected taxa across most VF sites and two functional feeding groups (% scrapers and %shredders) were significantly altered. Percent VF and forested area were related to biological quality but varied more than individual ions and specific conductance. Within the subset of VF sites, other descriptors (e.g., VF age, site distance from VF, the presence of impoundments, % forest) had no detectable relationships with biological condition. Although these VFs were constructed pursuant to permits and regulatory programs that have as their stated goals that (1) mined land be reclaimed and restored to its original use or a use of higher value, and (2) mining does not cause or contribute to violations of water quality standards, we found sustained ecological damage in headwaters streams draining VFs long after reclamation was completed.

  13. POP bioaccumulation in macroinvertebrates of alpine freshwater systems. (United States)

    Bizzotto, E C; Villa, S; Vighi, M


    This study serves to investigate the uptake of POPs in the different trophic levels (scrapers, collectors, predators, shredders) of macroinvertebrate communities sampled from a glacial and a non-glacial stream in the Italian Alps. The presented results show that the contaminant concentrations in glacial communities are generally higher compared to those from non-glacial catchments, highlighting the importance of glaciers as temporary sinks of atmospherically transported pollutants. Moreover, the data also suggests that in mountain systems snow plays an important role in influencing macroinvertebrate contamination. The main chemical uptake process to the macroinvertebrates is considered to be bioconcentration from water, as similar contaminant profiles were observed between the different trophic levels. The role of biomagnification/bioaccumulation is thought to be absent or negligible. The enrichment of chemicals observed in the predators is likely to be related to their greater lipid content compared to that of other feeding groups.

  14. Do lake littoral benthic invertebrates respond differently to eutrophication, hydromorphological alteration, land use and fish stocking?

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    Šiling Rebeka


    Full Text Available In order to provide adequate guidelines in freshwater management, managers need reliable bioindicators that can respond differently to varied stressors. Managers also have to consider hierarchical structure of environmental factors. Thus, our research aims to test the independence of taxa responses along environmental gradients and to examine in what order natural and anthropogenic factors constrain the structure of littoral benthic assemblages. The rank of explained variance of littoral benthic assemblage's variable group hierarchy was: land use > landscape characteristics > eutrophication > fish stocking > hydromorphological alteration. We determined nine gradients (two natural and seven stressor gradients, separated into five groups based on statistically significant differences in responsiveness of taxa. Apart from responsiveness to natural factors, littoral benthic invertebrates could be used as bioindicators for stressors reflecting urbanization, eutrophication, hydromorphological alteration and fish stocking. The taxonomical composition of littoral benthic invertebrates, especially when taxa with preference for certain relatively narrow environmental conditions along gradients are present, can be used to identify effects of key stressors. Our findings have profound implications for ecological assessment and management of lakes, as they indicate that benthic invertebrates can be used when the effects of multiple stressors need to be disentangled.

  15. Benthic Foraminifera, Food in the Deep Sea, and Limits to Bentho-Pelagic Coupling (United States)

    Thomas, E.; Boscolo-Galazzo, F.; Arreguin-Rodrigu, G. J.; Ortiz, S.; Alegret, L.


    The deep-sea is the largest habitat on Earth, contains highly diverse biota, but is very little known. Many of its abundant benthic biota (e.g., nematodes) are not preserved in the fossil record. Calcareous and agglutinated benthic foraminifera (unicellular eukaryotes, Rhizaria; efficient dispersers) and ostracodes (Animalia, Crustacea; non-efficient dispersers) are the most common organisms providing a fossil record of deep-sea environments. Very little food is supplied to the deep-sea, because organic matter produced by photosynthesis is largely degraded before it arrives at the seafloor. Only a few % of organic matter is carried to the ocean bottom by 'marine snow', with its particle size and behavior in the water column controlled by surface ecosystem structure, including type of dominant primary producers (diatoms, cyanobacteria). Food supply and its seasonality are generally seen as the dominant control on benthic assemblages (combined with oxygenation), providing bentho-pelagic coupling between primary and benthic productivity. Benthic foraminiferal assemblages (composition and density) thus are used widely to estimate past productivity, especially during episodes of global climate change, ocean acidification, and mass extinction of primary producers. We show that some environmental circumstances may result in interrupting bentho-pelagic coupling, e.g. through lateral supply of organic matter along continental margins (adding more refractory organic matter), through trophic focusing and/or fine particle winnowing on seamounts (giving an advantage to suspension feeders), and through carbonate undersaturation (giving advantage to infaunal over epifaunal calcifyers). In addition, increased remineralization of organic matter combined with increased metabolic rates may cause assemblages to reflect more oligotrophic conditions at stable primary productivity during periods of global warming. As a result, benthic foraminiferal accumulation rates must be carefully

  16. Combining taxonomy and function in the study of stream macroinvertebrates

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    Kenneth W. Cummins


    Full Text Available Over the last fifty years, research on freshwater macroinvertebrates has been driven largely by the state of the taxonomy of these animals. In the great majority of studies conducted during the 2000s macroinvertebrates have been operationally defined by investigators as invertebrates retained by a 250 μ mesh in field sampling devices. Significant advances have been and continue to be made in developing ever more refined keys to macroinvertebrate groups. The analysis by function is a viable alternative when advances in macroinvertebrate ecological research is restricted by the level of detail in identifications. Focus on function, namely adaptations of macroinvertebrates to habitats and the utilization of food resources, has facilitated ecological evaluation of freshwater ecosystems (Functional feeding groups; FFG. As the great stream ecologist Noel Hynes observed, aquatic insects around the world exhibit similar morphologies and behaviors, even though they are in very different taxonomic groups. This is the basis for the FFG analysis that was initially developed in the early 1970s. FFG analysis applies taxonomy only to the level of detail that allows assignment to one of six FFG categories: scrapers adapted to feed on periphyton, detrital shredders adapted to feed on coarse (CPOM riparian-derived plant litter that has been colonized by microbes, herbivore shredders that feed on live, rooted aquatic vascular plants, filtering collectors adapted to remove fine particle detritus (FPOM from the water column, gathering collectors adapted to feed on FPOM where it is deposited on surfaces or in crevices in the sediments, and predators that capture live prey. The interacting roles of these FFGs in stream ecosystems were originally depicted in a conceptual model. Thus, there are a limited number of adaptations exhibited by stream macroinvertebrates that exploit these habitats and food resources. This accounts for the wide range of macroinvertebrate taxa

  17. Stream Macroinvertebrate Occurrence along Gradients in Organic Pollution and Eutrophication

    DEFF Research Database (Denmark)

    Friberg, Nikolai; Skriver, Jens; Larsen, Søren Erik


    We analysed a large number of concurrent samples of macroinvertebrate communities and chemical indicators of eutrophication and organic pollution [total-P, total-N, NH4-N, biological oxygen demand (BOD5)] from 594 Danish stream sites. Samples were taken over an 11-year time span as part of the Da......We analysed a large number of concurrent samples of macroinvertebrate communities and chemical indicators of eutrophication and organic pollution [total-P, total-N, NH4-N, biological oxygen demand (BOD5)] from 594 Danish stream sites. Samples were taken over an 11-year time span as part...

  18. Effects of the “Run-of-River” Hydro Scheme on Macroinvertebrate Communities and Habitat Conditions in a Mountain River of Northeastern China

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    Haoran Wang


    Full Text Available The main objective of this study was to quantify the impacts of the run of river (ROR scheme on the instream habitat and macroinvertebrate community. We sampled the macroinvertebrate assemblages and collected the habitat variables above and below an ROR hydropower plant: Aotou plant in the Hailang River, China. The effects of the ROR scheme on habitat conditions were examined using regulation-related variables, most of which, particularly the hydrological variables and substrate composition, presented spatial variations along the downstream direction, contributing to heterogeneous conditions between reaches. The macroinvertebrate richness, the density and the diversity metrics showed significant decreases in the “depleted” reach compared with the upper and lower reaches. Approximately 75% of reach-averaged densities and 50% of taxa richness suffered decreases in the “depleted” reach compared with the upper reach. Furthermore, functional feeding groups also showed distinct site differences along the channel. The relative abundance of both collector-gatherers and the scrapers reduced considerably at the “depleted” sites, particularly at the site immediately downstream of the weir. The total variance in the the functional feeding group (FFG data explained by Canonical correlation analysis (CCA was more than 81.4% and the high-loadings factors were depth, flow velocity, DO and substrate composition. We demonstrated that flow diversion at the 75% level and an in-channel barrier, due to the ROR scheme, are likely to lead to poor habitat conditions and decrease both the abundance and the diversity of macroinvertebrates in reaches influenced by water diversion.

  19. 大型底栖无脊椎动物不同分类阶元对水生态评价的影响%Effects of Macroinvertebrate Taxonomic Resolution on Water Ecological Assessment

    Institute of Scientific and Technical Information of China (English)

    吴东浩; 徐兆安; 王备新; 张咏; 厉以强; 沈燕飞


    以江苏苏北地区主要河流为研究对象,探讨底栖动物不同分类阶元对水生态评价的影响.结果表明,在仅包括软体动物、摇蚊和寡毛类物种水平和属级水平的nMDS排序图上,样点间的相对距离和位置未发生变化.与物种水平相比,属级水平丢失的信息(<5%)小于科级水平(7%),且分类单元数与物种水平分类单元数呈极显著正相关(r =0.88,P<0.01).鉴定至属级水平较物种级水平不仅可节省大量的人力、物力和时间,而且可降低鉴定错误的概率;鉴定水平的统一能提高不同地区生态评价结果的可比性.因此,建议在长三角河网地区开展水生态评价时,采用鉴定至属级水平的软体动物、摇蚊和寡毛类较为合适.%The effects of different taxonomie resolutions on water ecological assessment was investigated by using data of benthic macroinvertebrate assemblages collected from 49 river sites in northern Jiangsu Province. The results showed that, based only on data of mollusca, chironomidae and oligochaeta, there were no differences in the location and relative distance among sites on the non-metric multidimensional scaling ordinations (nMDS) at the species or genus level. The information loss was less on the genus level ( <5% ) than on the family level (7 % ) , and the genus-level richness was strongly correlated with that of the species level ( r = 0. 88, P < 0. 01). There was no difference in accuracy of ecological condition assessment between coarse taxonomical level and species level. It costs much less to obtain information from family or genus level instead of species level, and identification errors can be reduced. The consistency of taxonomical resolution among different bioassessment programs increases the potential of inter-regional comparison from different ecological conditions. Our results suggested that the use of genus level in the combination of mollusca, chironomidae and oligochaeta was proper in

  20. Qualitative Macroinvertebrate Assessment of Crouch Branch, June 1999

    Energy Technology Data Exchange (ETDEWEB)

    Specht, W.L.


    An assessment of the macroinvertebrate community of Crouch Branch was performed in June 1999 to determine if effluent from the H-02 outfall is impairing the quality of the stream. Concurrent samples were collected for metals analyses (copper and zinc). The results of the study indicate that the stream is most impaired just downstream from the H-02 outfall and that the quality of the stream biota improves with increasing distance from the outfall. Conversely, macroinvertebrate habitat quality is best just downstream from the H-02 outfall. The midreaches of the stream contain very poor habitat quality, and the lower reaches of the stream, contain habitat of intermediate quality. Although much of the stream has degraded habitat due to channel erosion and scouring, there is strong evidence to suggest that the impairment is due to elevated concentrations of copper and zinc that are present in the H-02 effluent. A comparison of macroinvertebrate data collected in 1997 to the data collected in this study indicates that the macroinvertebrate community of Crouch Branch has improved markedly in the last two years.

  1. Are sugarcane leaf-detritus well colonized by aquatic macroinvertebrates?

    Directory of Open Access Journals (Sweden)

    Luciene Aparecida Leite-Rossi

    Full Text Available AIM: The aim was to compare the kinetics of decomposition and the colonization of leaf litter of two plant species, the native Talauma ovata (pinha-do-brejo and the exotic Saccharum officinarum (sugarcane, by aquatic macroinvertebrates; METHODS: From each substrate, three recipients of colonization were taken from a stream, and the specimens identified to the lowest taxonomic level on days 7, 15, 34, 44, 61 and 75. The debris was weighed at the beginning and end of the experiment and determined their cell wall fractions; RESULTS: The coefficients of mineralization indicated higher velocity decay of organic matter refractory in T. ovata. There was no difference in taxonomic structure of macroinvertebrates, between the two substrates, but the community exhibited distinct functional feeding groups in the peak of colonization, with a greater number of shredders in T. ovata. The successive states of decomposition of the two plant detritus showed distinct macroinvertebrate densities; CONCLUSIONS: The amount and state of the plant biomass were important factors influencing the density and diversity of the macroinvertebrate fauna throughout the process of organic decomposition.

  2. Temporal changes of a macrobenthic assemblage in harsh lagoon sediments (United States)

    Como, Serena; Magni, Paolo


    An opportunistic macrobenthic assemblage was studied from 2001 to 2003 in a central area of the Cabras lagoon (western Sardinia, Italy), known to be affected by environmental disturbances (i.e. organic over-enrichment of sediments, and episodic events of hypoxia/anoxia and sulphide development). We identified recurrent seasonal changes in this macrobenthic assemblage, with a general impoverishment in summer and a recovery in winter/spring. The nereids Neanthes succinea and Hediste diversicolor were found to replace the spionid Polydora ciliata as the most dominant species in the summer for 3 consecutive years. Occasional, unsynchronized appearances of small-sized deposit feeders, such as Tubificidae, Capitella cf. capitata, chironomid larvae and Hydrobia spp., were observed in winter/spring. We suggest that these changes are driven by the interplay of environmental conditions (worse in summer) with numerous biotic factors. This includes different tolerance levels of taxa to low oxygen concentrations and sulphides, variability in larval supply and post-larval transport, as well as competition for space and food between and within different functional groups, and facilitation through animal bioturbation and sediment reoxidation. A conceptual model is proposed to demonstrate how environmental conditions and biotic interactions may control the benthic assemblage in such a harsh lagoon environment.

  3. Correspondence between zooplankton assemblages and the Estuary Environment Classification system (United States)

    Lucena-Moya, Paloma; Duggan, Ian C.


    We tested whether variability in zooplankton assemblages was consistent with the categories of estuarine environments proposed by the 'Estuary Environment Classification' system (EEC) (Hume et al., 2007) across a variety of North Island, New Zealand, estuaries. The EEC classifies estuaries in to eight categories (A to F) based primarily on a combination of three abiotic controlling factors: ocean forcing, river forcing and basin morphometry. Additionally, we tested whether Remane's curve, which predicts higher diversities of benthic macrofauna and high and low salinities, can be applied to zooplankton assemblages. We focused on three of the eight EEC categories (B, D and F), which covered the range of estuaries with river inputs dominating (B) to ocean influence dominating (F). Additionally, we included samples from river (FW) and sea (MW) to encompass the entire salinity range. Zooplankton assemblages varied across the categories examined in accordance with a salinity gradient predicted by the EEC. Three groups of zooplankton were distinguishable: the first formed by the most freshwater categories, FW and B, and dominated by rotifers (primarily Bdelloidea) and estuarine copepods (Gladioferans pectinatus), a second group formed by categories D and F, of intermediate salinity, dominated by copepods (Euterpina acutifrons), and a final group including the purely marine category MW and dominated also by E. acutifrons along with other marine taxa. Zooplankton diversity responded to the salinity gradient in a manner expected from Remane's curve. The results of this study support others which have shown salinity to be the main factor driving zooplankton community composition and diversity.

  4. Effects of a brine discharge over soft bottom Polychaeta assemblage

    Energy Technology Data Exchange (ETDEWEB)

    Pilar-Ruso, Yoana del [Dpto. de Ciencias del Mar y Biologia Aplicada, Universidad de Alicante, Campus de San Vicente del Raspeig, Ap. 99, E-03080, Alicante (Spain)], E-mail:; Ossa-Carretero, Jose Antonio de la; Gimenez-Casalduero, Francisca; Sanchez-Lizaso, Jose Luis [Dpto. de Ciencias del Mar y Biologia Aplicada, Universidad de Alicante, Campus de San Vicente del Raspeig, Ap. 99, E-03080, Alicante (Spain)


    Desalination is a growing activity that has introduced a new impact, brine discharge, which may affect benthic communities. Although the role of polychaetes as indicators to assess organic pollution is well known, their tolerance to salinity changes has not been examined to such a great extent. The aim of this study was to examine the effect of brine discharge over soft bottom polychaete assemblage along the Alicante coast (Southeast Spain) over a two year period. Changes in the polychaete assemblage was analysed using univariate and multivariate techniques. We compared a transect in front of the discharge with two controls. At each transect we sampled at three depths (4, 10 and 15 m) during winter and summer. We have observed different sensitivity of polychaete families to brine discharges, Ampharetidae being the most sensitive, followed by Nephtyidae and Spionidae. Syllidae and Capitellidae showed some resistance initially, while Paraonidae proved to be a tolerant family. - The Polychaete assemblage is affected by the brine discharge of the Alicante desalination plant and we detect different sensitivity levels in polychaete families to brine impact.

  5. The Farther the Better: Effects of Multiple Environmental Variables on Reef Fish Assemblages along a Distance Gradient from River Influences (United States)

    Neves, Leonardo M.; Teixeira-Neves, Tatiana P.; Pereira-Filho, Guilherme H.; Araújo, Francisco G.


    The conservation and management of site-attached assemblages of coastal reefs are particularly challenging because of the tremendous environmental variation that exists at small spatial scales. In this sense, understanding the primary sources of variation in spatial patterns of the biota is fundamental for designing effective conservation policies. We investigated spatial variation in fish assemblages around the windward and leeward sides of coastal islands situated across a gradient of riverine influence (13 km in length). Specifically, relationships between rocky reef fish assemblages and benthic, topographic and physical predictors were assessed. We hypothesized that river induced disturbances may overcome local habitat features in modeling spatial patterns of fish distribution. Fish assemblages varied primarily due to the strong directional gradient of riverine influence (22.6% of the estimated components of variation), followed by topographic complexity (15%), wave exposure (9.9%), and benthic cover (8%). The trophic structure of fish assemblages changed from having a high abundance of invertebrate feeders in macroalgae-dominated reefs close to river mouths to a high proportion of herbivores, planktivores and invertebrate feeder species in reefs with large boulders covered by epilithic algal matrices, as the distance from rivers increased. This gradient led to an increase of 4.5-fold in fish richness and fish trophic group diversity, 11-fold in fish biomass and 10-fold in fish abundance. Our results have implications for the conservation and monitoring of assemblages patchily distributed at small spatial scales. The major role of distance from river influences on fish assemblages rather than benthic cover and topographic complexity suggest that managing land-based activities should be a conservation priority toward reef restoration. PMID:27907017

  6. American Samoa ESI: BENTHIC (Benthic Marine Habitat Polygons) (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for benthic habitats in American Samoa. Vector polygons in this data set represent the distribution of...

  7. Abnormal test growth in benthic foraminifera from hypersaline coastal ponds of the United Arab Emirates (United States)

    Fiorini, Flavia; Lokier, Stephen W.


    The living (Rose-Bengal stained) benthic foraminifera assemblage from shallow coastal ponds located in the intertidal area of the United Arab Emirate Western Region was investigated. The studied coastal ponds are located between a lagoonal area, characterized by carbonate sedimentation, and the supratidal, evaporite-dominated, sabkha. Sampling was undertaken when the maximum water depth in the ponds was 50 cm with a water temperature ranging from 27 to 35°C, a pH of 8 and a maximum salinity of 60 ppt. The sides and floor of the pond were characterized by a microbial mat. Detached blades of sea grass were present in the ponds and are inferred to have been transported into the pond either during high-tides or storm surges. Collected samples were stained with Rose-Bengal at the moment of sample collection and the living assemblage was studied. The benthic foraminifera that were present show a low-diversity assemblage. Epiphytic larger benthic foraminifera dominate the living assemblage with Peneroplis pertusus and P. planatus characterizing 90% of the living assemblage and the species Spirolina areatina, S. aciculata, Sorites marginalis and Quinqueloculina spp. comprising the rest of the foraminifera community. High percentages (up to 50% of the stained assemblage) of anomalous tests of benthic foraminifera belonging to the genera Peneroplis, Spirolina and Sorites were observed. The anomalies included dissolution, microboring and abnormality in growth. Three different forms of abnormal shell architecture were recorded; the presence of multiple apertures with reduced size, deformation in the general shape of the test and abnormal coiling. The high percentage of abnormal tests reflects natural environmental stress caused by instability of physical parameters (particularly high and variable salinity and temperature) in this kind of transitional marine environment. The unique presence of epiphytic species, suggests that epiphytic foraminifera may be transported into the

  8. Macrozoobenthic assemblages in relation to environments of the Yangtze-isolated lakes

    Institute of Scientific and Technical Information of China (English)

    Baozhu PAN; Haijun WANG; Hongzhu WANG; Zhaoyin WANG


    Eutrophication can shift lakes from a clear, macrophyte-dominated state state, and different habitat to a turbid, algae-dominated condition supports different fauna. Macrozoobenthos are good indicators of water environment, and studies on macrozoobenthic assemblage characteristics can help us to know which state a lake is in, thus provide the basis for its eutrophication control. In this study, a systematic investigation on macrozoobenthos was conducted in 17 Yangtze-isolated lakes to explore the macroecological laws of macrozoobenthic assemblages. Detrended correspondence analysis (DCA) revealed that variance of benthic assemblage structure occurred in two types of lakes. In macrophytic lakes, altogether 51 taxa of macrozoobenthos were identified. The average density and biomass of total macrozoobenthos were 2231 individuals, m2 and 1.69 g dry weight.m-2, respec- tively. Macrozoobenthic assemblage was characterized by dominance of scrapers (i.e. gastropods). In algal lakes, altogether 20 taxa of macrozoobenthos were identified. The average density and biomass of total macrozoobenthos were 2814 individuals.m~2 and 1.38g dry weight.m-2, respectively. Macrozoobenthic assemblage was character- ized by dominance of collector-gatherers (i.e. oligo- chaetes). Wet biomass of submersed macrophytes (BMac) and phytoplankton chlorophyll a concentration (Chla) were demonstrated as the key factor structuring macro- zoobenthic assemblages in macrophytic and algal lakes, respectively.

  9. Bioassessment on Water Quality Based on Biotic Integrity Index of Macroinvertebrate in Representative Sections of Dongting Lake, China%基于底栖动物完整性指数的洞庭湖典型断面的水质评价

    Institute of Scientific and Technical Information of China (English)

    汪星; 郑丙辉; 李黎; 刘录三; 李利强; 黄代中; 田琪


    2010年在枯水期、平水期、丰水期对洞庭湖的7个典型断面进行了大型底栖无脊椎动物采样,共获得底栖动物40种,其中节肢动物16种、软体动物18种,环节动物6种.根据Shannon-Wiener物种多样性指数确定了4个相对清洁的断面和3个污染断面,然后进行23种生物指数的综合评估,结果表明,(甲壳动物+软体动物)分类单元数、Shannon-Wiener物种多样性指数与Goodnight-Whitley指数3个底栖动物生物指数可以用作辨别洞庭湖典型断面水质的敏感生物指数.通过5、3、1记分法对3种生物指数统一量纲后,获得变化范围为3~15的综合生物指数,运用四分法划分出洞庭湖典型断面水质辨别的生物基准:3~6,差;7~9,一般;10~12,好;13~15,很好.据此对7个断面进行重新记分,获得了洞庭湖典型断面水质的基本分区现状:虞公庙、万子湖、目平湖3个断面的水质良好,而鹿角、坡头、南嘴及东洞庭湖4个断面的水质较差.该水质生物学基准基本适合评价洞庭湖典型断面的水质状况.%To develop benthic macroinvertebrate based multmietrics for the bioassessment of the water quality of Dongting Lake, benthic macroinvertebrate assemblages were sampled at 7 sections of Dongting Lake in different seasons in 2010. A total of 40 species of the benthos were collected: 16 species of Arthropoda, 18 species of Mollusca and 6 species of Annelida. The dominant benthos had an abundance ranging from 32 to 208 individuals -m"2 and obviously different across the sampling sections. Based on Shannon-Wiener biotic index discriminatory criteria, 4 sections were considered relatively clean while the remaining 3 sections were polluted. A comprehensive evaluation of 23 metrics was carried out. The results showed that 3 metrics(.i e., No. of Mollusca & Crustacea Taxa, Shannon-Wiener Species Diversity Index and Goodnight-Whitley Index) were sensitive. A score of 5, 3 or 1 was assigned to

  10. Benthic foraminifera show some resilience to ocean acidification in the northern Gulf of California, Mexico. (United States)

    Pettit, L R; Hart, M B; Medina-Sánchez, A N; Smart, C W; Rodolfo-Metalpa, R; Hall-Spencer, J M; Prol-Ledesma, R M


    Extensive CO2 vents have been discovered in the Wagner Basin, northern Gulf of California, where they create large areas with lowered seawater pH. Such areas are suitable for investigations of long-term biological effects of ocean acidification and effects of CO2 leakage from subsea carbon capture storage. Here, we show responses of benthic foraminifera to seawater pH gradients at 74-207m water depth. Living (rose Bengal stained) benthic foraminifera included Nonionella basispinata, Epistominella bradyana and Bulimina marginata. Studies on foraminifera at CO2 vents in the Mediterranean and off Papua New Guinea have shown dramatic long-term effects of acidified seawater. We found living calcareous benthic foraminifera in low pH conditions in the northern Gulf of California, although there was an impoverished species assemblage and evidence of post-mortem test dissolution.

  11. Testing benthic foraminiferal distributions as a contemporary quantitative approach to biomonitoring estuarine heavy metal pollution. (United States)

    Foster, William J; Armynot du Châtelet, Eric; Rogerson, Mike


    Biomonitoring of estuarine pollution is the subject of active research, and benthic foraminifera are an attractive group to use for these purposes due to their ubiquitous presence in saline water and wide diversity. Here, we describe a case study of biomonitoring using benthic foraminifera in the French Mediterranean lagoon, Bages-Sigean lagoon. In this case, the major pollutants of interest are heavy metals in the sediment, particularly contaminated by Cu and Cd derived from industrial and agricultural sources. The foraminiferal assemblages of the Bages-Sigean lagoon are typical of normal paralic environments, but unusually almost completely lack agglutinated forms. The density of benthic foraminifera was shown to be more influenced by the sediment characteristics rather than heavy metal pollution. However, the relative abundance of Quinqueloculina bicostata was shown to increase in the most polluted areas and we propose that this taxon may be used as an indicator of heavy metal pollution.

  12. NEPR Benthic Habitat Map 2015 (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This benthic habitat map was created from a semi-automated habitat mapping process, using a combination of bathymetry, satellite imagery, aerial imagery and...

  13. National Benthic Infaunal Database (NBID) (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NBID is a quantitative database on abundances of individual benthic species by sample and study region, along with other synoptically measured environmental...

  14. Benthic fauna of mangrove environment

    Digital Repository Service at National Institute of Oceanography (India)

    Parulekar, A.H.

    The distribution, abundance and importance of benthic fauna in a mangrove environment has been discussed. This ecosystem is enriched with terrestrial, aquatic, marshy and mudflat species mangrove environment. Qualitative and quantitative...

  15. Macroinvertebrates as indicators of fish absence in naturally fishless lakes (United States)

    Schilling, Emily Gaenzle; Loftin, C.S.; Huryn, Alexander D.


    1. Little is known about native communities in naturally fishless lakes in eastern North America, a region where fish stocking has led to a decline in these habitats. 2. Our study objectives were to: (i) characterise and compare macroinvertebrate communities in fishless lakes found in two biophysical regions of Maine (U.S.A.): kettle lakes in the eastern lowlands and foothills and headwater lakes in the central and western mountains; (ii) identify unique attributes of fishless lake macroinvertebrate communities compared to lakes with fish and (iii) develop a method to efficiently identify fishless lakes when thorough fish surveys are not possible. 3. We quantified macroinvertebrate community structure in the two physiographic fishless lake types (n = 8 kettle lakes; n = 8 headwater lakes) with submerged light traps and sweep nets. We also compared fishless lake macroinvertebrate communities to those in fish-containing lakes (n = 18) of similar size, location and maximum depth. We used non-metric multidimensional scaling to assess differences in community structure and t-tests for taxon-specific comparisons between lakes. 4. Few differences in macroinvertebrate communities between the two physiographic fishless lake types were apparent. Fishless and fish-containing lakes had numerous differences in macroinvertebrate community structure, abundance, taxonomic composition and species richness. Fish presence or absence was a stronger determinant of community structure in our study than differences in physical conditions relating to lake origin and physiography. 5. Communities in fishless lakes were more speciose and abundant than in fish-containing lakes, especially taxa that are large, active and free-swimming. Families differing in abundance and taxonomic composition included Notonectidae, Corixidae, Gyrinidae, Dytiscidae, Aeshnidae, Libellulidae and Chaoboridae. 6. We identified six taxa unique to fishless lakes that are robust indicators of fish absence: Graphoderus

  16. Characterizing lentic freshwater fish assemblages using multiple sampling methods (United States)

    Fischer, Jesse R.; Quist, Michael


    Characterizing fish assemblages in lentic ecosystems is difficult, and multiple sampling methods are almost always necessary to gain reliable estimates of indices such as species richness. However, most research focused on lentic fish sampling methodology has targeted recreationally important species, and little to no information is available regarding the influence of multiple methods and timing (i.e., temporal variation) on characterizing entire fish assemblages. Therefore, six lakes and impoundments (48–1,557 ha surface area) were sampled seasonally with seven gear types to evaluate the combined influence of sampling methods and timing on the number of species and individuals sampled. Probabilities of detection for species indicated strong selectivities and seasonal trends that provide guidance on optimal seasons to use gears when targeting multiple species. The evaluation of species richness and number of individuals sampled using multiple gear combinations demonstrated that appreciable benefits over relatively few gears (e.g., to four) used in optimal seasons were not present. Specifically, over 90 % of the species encountered with all gear types and season combinations (N = 19) from six lakes and reservoirs were sampled with nighttime boat electrofishing in the fall and benthic trawling, modified-fyke, and mini-fyke netting during the summer. Our results indicated that the characterization of lentic fish assemblages was highly influenced by the selection of sampling gears and seasons, but did not appear to be influenced by waterbody type (i.e., natural lake, impoundment). The standardization of data collected with multiple methods and seasons to account for bias is imperative to monitoring of lentic ecosystems and will provide researchers with increased reliability in their interpretations and decisions made using information on lentic fish assemblages.

  17. Benthic processes affecting contaminant transport in Upper Klamath Lake, Oregon (United States)

    Kuwabara, James S.; Topping, Brent R.; Carter, James L.; Carlson, Rick A; Parchaso, Francis; Fend, Steven V.; Stauffer-Olsen, Natalie; Manning, Andrew J.; Land, Jennie M.


    flow across the interface through bioirrigation, and (3) excreting or expelling dissolved or particulate solutes directly into the overlying water column (Boudreau and Jorgensen, 2001). We evaluated SRP efflux via excretion for approximately 15 different major taxa in UKL. Once these measures were scaled, it was evident that benthic invertebrates potentially contribute approximately 1.5 times the amount of SRP to the water column of Upper Klamath Lake as diffusive SRP flux alone, measured in profiler deployments. Sets of piezometers and temperature loggers were deployed in UKL to obtain estimates of vertical advective solute flux. The pressure transducer installations, within the piezometers, did not perform as designed, rendering the head gradient data unreliable. However, in terms of future research, this field work did demonstrate the feasibility of collecting vertical gradient data with piezometer deployments. Advective flux estimates herein are based solely on heat-flow modeling based on temperature data from four lake sites, without use of transducer data. Given the magnitudes (both positive or negative) of the heat-transfer fluxes for SRP, relative to diffusive-flux and macroinvertebrate efflux measurements (all positive but spanning the same orders of magnitude), further examination of solute advective flux is recommended as a potential transport process to integrate into existing water-quality (for example, Total Maximum Daily Load [TMDL]) models. As a complement to the biogeochemical focus of this study, initial analyses of suspended-particle (floc) characteristics and settling velocities from the water column were derived near the surface and lakebed at two UKL sites. To better understand changing particle characteristics during the AFA-bloom period, suspended particles were examined in 2015 using a LabSFLOC (LF), which is a Laboratory Spectral Flocculation Characteristics version of an In-Situ Settling Velocity instrument (INSSEV-LF). Particle

  18. Spatial variability of benthic-pelagic coupling in an estuary ecosystem: consequences for microphytobenthos resuspension phenomenon.

    Directory of Open Access Journals (Sweden)

    Martin Ubertini

    Full Text Available The high degree of physical factors in intertidal estuarine ecosystem increases material processing between benthic and pelagic compartments. In these ecosystems, microphytobenthos resuspension is a major phenomenon since its contribution to higher trophic levels can be highly significant. Understanding the sediment and associated microphytobenthos resuspension and its fate in the water column is indispensable for measuring the food available to benthic and pelagic food webs. To identify and hierarchize the physical/biological factors potentially involved in MPB resuspension, the entire intertidal area and surrounding water column of an estuarine ecosystem, the Bay des Veys, was sampled during ebb tide. A wide range of physical parameters (hydrodynamic regime, grain size of the sediment, and suspended matter and biological parameters (flora and fauna assemblages, chlorophyll were analyzed to characterize benthic-pelagic coupling at the bay scale. Samples were collected in two contrasted periods, spring and late summer, to assess the impact of forcing variables on benthic-pelagic coupling. A mapping approach using kriging interpolation enabled us to overlay benthic and pelagic maps of physical and biological variables, for both hydrological conditions and trophic indicators. Pelagic Chl a concentration was the best predictor explaining the suspension-feeders spatial distribution. Our results also suggest a perennial spatio-temporal structure of both benthic and pelagic compartments in the ecosystem, at least when the system is not imposed to intense wind, with MPB distribution controlled by both grain size and bathymetry. The benthic component appeared to control the pelagic one via resuspension phenomena at the scale of the bay. Co-inertia analysis showed closer benthic-pelagic coupling between the variables in spring. The higher MPB biomass observed in summer suggests a higher contribution to filter-feeders diets, indicating a higher

  19. Effects of coral reef benthic primary producers on dissolved organic carbon and microbial activity.

    Directory of Open Access Journals (Sweden)

    Andreas F Haas

    Full Text Available Benthic primary producers in marine ecosystems may significantly alter biogeochemical cycling and microbial processes in their surrounding environment. To examine these interactions, we studied dissolved organic matter release by dominant benthic taxa and subsequent microbial remineralization in the lagoonal reefs of Moorea, French Polynesia. Rates of photosynthesis, respiration, and dissolved organic carbon (DOC release were assessed for several common benthic reef organisms from the backreef habitat. We assessed microbial community response to dissolved exudates of each benthic producer by measuring bacterioplankton growth, respiration, and DOC drawdown in two-day dark dilution culture incubations. Experiments were conducted for six benthic producers: three species of macroalgae (each representing a different algal phylum: Turbinaria ornata--Ochrophyta; Amansia rhodantha--Rhodophyta; Halimeda opuntia--Chlorophyta, a mixed assemblage of turf algae, a species of crustose coralline algae (Hydrolithon reinboldii and a dominant hermatypic coral (Porites lobata. Our results show that all five types of algae, but not the coral, exuded significant amounts of labile DOC into their surrounding environment. In general, primary producers with the highest rates of photosynthesis released the most DOC and yielded the greatest bacterioplankton growth; turf algae produced nearly twice as much DOC per unit surface area than the other benthic producers (14.0±2.8 µmol h⁻¹ dm⁻², stimulating rapid bacterioplankton growth (0.044±0.002 log10 cells h⁻¹ and concomitant oxygen drawdown (0.16±0.05 µmol L⁻¹ h⁻¹ dm⁻². Our results demonstrate that benthic reef algae can release a significant fraction of their photosynthetically-fixed carbon as DOC, these release rates vary by species, and this DOC is available to and consumed by reef associated microbes. These data provide compelling evidence that benthic primary producers differentially influence

  20. Ecological Effects of Biochar on the Structure and Function of Stream Benthic Communities. (United States)

    Clements, William H; Stahl, Ralph G; Landis, Richard C


    The introduction of biochar, activated carbon, and other carbonaceous materials to aquatic ecosystems significantly reduces the toxicity and bioavailability of contaminants. However, previous studies have shown that these materials can have negative effects on aquatic organisms. We conducted field and mesocosm experiments to test the hypothesis that biochar altered the structure and function of stream benthic communities. After 30 d in the field, colonization by stoneflies (Plecoptera) was significantly lower in trays containing biochar compared to the results from the controls. In stream mesocosms, biochar increased macroinvertebrate drift and significantly reduced community metabolism. However, most measures of community composition showed little variation among biochar treatments, and significant responses were limited to a single stonefly species (Capnia confusa). When benthic communities were simultaneously exposed to biochar and Cu, effects were primarily associated with metal exposure. Because it is unlikely that biochar treatments would be employed in uncontaminated areas, these moderately negative effects should be considered within the context of the positive benefits associated with reduced contaminant bioavailability and toxicity. Additional research is necessary to improve our understanding of the mechanisms responsible for biochar effects on benthic communities and to identify the optimal application rates and size fractions that will maximize contaminant sorption but minimize potential negative effects.

  1. Assessing benthic ecological status in stressed Liaodong Bay (China) with AMBI and M-AMBI

    Institute of Scientific and Technical Information of China (English)

    CAI Wenqian; MENG Wei; ZHU Yanzhong; ZHOU Juan; LIU Lusan


    Rapid economic development in recent decades has resulted in environmental degradation of Liaodong Bay,North China,where eutrophication is becoming more evident because of excess nutrients inputs.To assess the benthic ecological status in Liaodong Bay,AZTI's Marine Biotic Index (AMBI) and multivariate-AMBI (M-AMBI) were applied using both benthic macroinvertebrate density and biomass data collected from Liaodong Bay in July 2007.This first application of AMBI and M-AMBI in Liaodong Bay showed that the nearshore areas of the bay,especially near river estuaries,were severely disturbed,with a clear gradient of disturbance decreasing seaward.Ecological status assessed from density and biomass data was quite similar.Significant relationships were also found between both indices and environmental variables in Liaodong Bay.Moreover,the spatial distributions of both AMBI and M-AMBI matched those of plotted eutrophication indices (EI) in the surface water layer,and significant linear correlations were found between both benthic indices and EI.In general,both AMBI and M-AMBI worked well on assessing the ecological status of Liaodong Bay under eutrophication stress due to excess nutrients inputs.

  2. A Stream Multimetric Macroinvertebrate Index (MMI) for the Sand Hills Ecoregion of the Southeastern Plains, USA (United States)

    Kosnicki, Ely; Sefick, Stephen A.; Paller, Michael H.; Jerrell, Miller S.; Prusha, Blair A.; Sterrett, Sean C.; Tuberville, Tracey D.; Feminella, Jack W.


    A macroinvertebrate multimetric index is an effective tool for assessing the biological integrity of streams. However, data collected under a single protocol may not be available for an entire region. We sampled macroinvertebrates from the full extent of the Sand Hills ecoregion Level IV of the Southeastern Plains with a standard protocol during the summers of 2010-2012. We evaluated the performance of 94 metrics through a series of screening criteria and built 48 macroinvertebrate multimetric indexs with combinations of the best performing metrics, representing richness, habit, functional feeding guild, sensitivity, and community composition. A series of narrative-response tests for each macroinvertebrate multimetric index was used to find the best performing macroinvertebrate multimetric index which we called the Sand Hills macroinvertebrate multimetric index. The Sand Hills macroinvertebrate multimetric index consisted of the measures Biotic Index, % Shredder taxa, Clinger taxa2/total taxa, Plecoptera and Trichoptera richness, and Tanytarsini taxa2/Chironomidae taxa. Comparison of the Sand Hills macroinvertebrate multimetric index with existing assessment tools calculated with our data indicated that the Sand Hills macroinvertebrate multimetric index performs at a high level with regard to identifying degraded sites and in its response to stress gradients.

  3. Impacts of Shorebirds on Macroinvertebrates in the Lower Mississippi Alluvial Valley (United States)

    US Fish and Wildlife Service, Department of the Interior — Study of the impacts of migratory birds by assessing macroinvertebrate community composition, abundance and biomass associated with habitats.

  4. POPs data for salmonids and macroinvertebrates from Glacier Bay, Alaska - Measuring persistent organic pollutants in resident salmonids and benthic macroinvertebrates in streams near Glacier National Park, Alaska (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A 2007 pilot study was initiated by the University of Alaska Southeast in which baseline levels of contaminants, including persistent organic pollutants (POPs) and...

  5. Stream habitat structure influences macroinvertebrate response to pesticides

    DEFF Research Database (Denmark)

    Rasmussen, Jes; Wiberg-Larsen, Peter; Baattrup-Pedersen, Annette;


    Agricultural pesticide contamination in surface waters is increasingly threatening to impair the surface water ecosystems. Agricultural streams are furthermore often heavily maintained to optimise the transport of water away from fields. The physical habitat degradation that result from heavy...... stream maintenance probably introduce additional stress that may act in concert with pesticide stress. We surveyed pesticide contamination and macroinvertebrate community structure in 14 streams along a gradient of expected pesticide exposure. A paired-reach approach was applied to differentiate...... the effects of pesticides between sites with degraded and more undisturbed physical properties. The effect of pesticides on macroinvertebrate communities (measured as the relative abundance of SPEcies At Risk) was increased at stream sites with degraded physical habitats primarily due to the absence...

  6. Relationships between physical and chemical factors and aquatic macroinvertebrates in perennial streams in the arid northern mountain basin El Batinah, Oman

    Directory of Open Access Journals (Sweden)

    S. Boulaaba


    Full Text Available The relationships between physical properties, water chemistry and aquatic macroinvertebrates were investigated in riffles of four perennial streams in the arid northern Oman. Samples were collected monthly in autumn, winter and spring with a Surber net. Thirty two invertebrate taxa were recorded, most species are widely distributed, but few species with very restricted distribution were also captured. Diptera followed by Pulmonata, Coleoptera and Odonata were the most represented taxa, Trichoptera and Heteroptera were a significant component only in one station (the Fezeh, where the lowest mean water temperature (23°C was recorded. In the dry months from May to October, aquatic macroinvertebrates were completely absent. In order to summarise the community response some biotic indices were calculated. The highest diversity was observed in the Fezeh station. A seasonal gradient was also observed, with the highest diversity values in January, April, and December. The low faunal diversity was attributed to the high air and water temperature and the hydrological regime instability. A between station and a between month coinertia analysis was carried out, to analyse the response to spatial and seasonal factors. The first coinertia axis was correlated with altitude and substrate composition, while the second axis was correlated with air and water temperature. The present research emphasizes the urgency for preserving the less disturbed wadis in arid zones, because, despite their species poorness, their uniqueness in faunal composition requires special attention. The presence of few endemic species with very restricted distribution highlights the topicality and the value in investigating these areas, allowing the increase of our knowledge on biodiversity, ecology and biogeography about the benthic macroinvertebrates living in these extreme habitats.

  7. Fire, flow and dynamic equilibrium in stream macroinvertebrate communities (United States)

    Arkle, R.S.; Pilliod, D.S.; Strickler, K.


    The complex effects of disturbances on ecological communities can be further complicated by subsequent perturbations within an ecosystem. We investigated how wildfire interacts with annual variations in peak streamflow to affect the stability of stream macroinvertebrate communities in a central Idaho wilderness, USA. We conducted a 4-year retrospective analysis of unburned (n = 7) and burned (n = 6) catchments, using changes in reflectance values (??NBR) from satellite imagery to quantify the percentage of each catchment's riparian and upland vegetation that burned at high and low severity. For this wildland fire complex, increasing riparian burn severity and extent were associated with greater year-to-year variation, rather than a perennial increase, in sediment loads, organic debris, large woody debris (LWD) and undercut bank structure. Temporal changes in these variables were correlated with yearly peak flow in burned catchments but not in unburned reference catchments, indicating that an interaction between fire and flow can result in decreased habitat stability in burned catchments. Streams in more severely burned catchments exhibited increasingly dynamic macroinvertebrate communities and did not show increased similarity to reference streams over time. Annual variability in macroinvertebrates was attributed, predominantly, to the changing influence of sediment, LWD, riparian cover and organic debris, as quantities of these habitat components fluctuated annually depending on burn severity and annual peak streamflows. These analyses suggest that interactions among fire, flow and stream habitat may increase inter-annual habitat variability and macroinvertebrate community dynamics for a duration approaching the length of the historic fire return interval of the study area. ?? 2009 Blackwell Publishing Ltd.

  8. Biological and physical conditions of macroinvertebrates in reference lowland streams (United States)

    de Brouwer, Jan; Eekhout, Joris; Verdonschot, Piet


    Channelisation measures taken halfway the 20th century have had destructive consequences for the diversity of the ecology in the majority of the lowland streams in countries such as the Netherlands. Currently, stream restoration measures are being implemented in these degraded lowland streams, where design principles are often based on outdated relationships between biological and physical conditions. Little is known about the reference conditions in these streams. Therefore, the aim of this research is to quantify the relationships between biological and physical conditions of macroinvertebrates in reference lowland streams. The research was conducted in four near-natural lowland streams in Central Poland. Field data were obtained during a field campaign in 2011. The following data were obtained in a 50-m reach in each of the four streams: macroinvertebrate sampling, spatial habitat patterns, bathymetry, and flow-velocity. Furthermore, water level, light sensitivity and temperature sensors were installed to obtain the temporal dynamic of these streams. Macroinvertebrates were sampled in 9 different habitat types, i.e. sand, gravel, fine organic matter, stones, branches, leaves, silt, vegetation, and wood. Macroinvertebrates were determined to the highest taxonomic level possible. Data from the bathymetrical surveys were interpolated on a grid and bathymetrical metrics were determined. Flow velocity measurements were related to habitats and flow velocity metrics were determined. Analysis of the data shows that flow conditions vary among the different habitat, with a gradient from hard substrates towards soft substrates. Furthermore, the data show that stream as a unit best explains species composition, but also specific habitat conditions, such as substrate type and flow velocity, correlate with species composition. More specific, the data shows a strong effect of wood on species composition. These findings may have implications for stream restoration design, which

  9. Modern diatom, cladocera, chironomid, and chrysophyte cyst assemblages as quantitative indicators for the reconstruction of past environmental conditions in the Alps. I. Climate

    NARCIS (Netherlands)

    Lotter, A.F.; Birks, H.J.B.; Hofmann, W.; Marchetto, A.


    Diatom, chrysophyte cyst, benthic cladocera, planktonic cladocera, and chironomid assemblages were studied in the surface sediments of 68 small lakes along an altitudinal gradient from 300 to 2350 m in Switzerland. In addition, 43 environmental variables relating to the physical limnology, geography

  10. Reef fishes of Saba Bank, Netherlands Antilles: assemblage structure across a gradient of habitat types.

    Directory of Open Access Journals (Sweden)

    Wes Toller

    Full Text Available Saba Bank is a 2,200 km(2 submerged carbonate platform in the northeastern Caribbean Sea off Saba Island, Netherlands Antilles. The presence of reef-like geomorphic features and significant shelf edge coral development on Saba Bank have led to the conclusion that it is an actively growing, though wholly submerged, coral reef atoll. However, little information exists on the composition of benthic communities or associated reef fish assemblages of Saba Bank. We selected a 40 km(2 area of the bank for an exploratory study. Habitat and reef fish assemblages were investigated in five shallow-water benthic habitat types that form a gradient from Saba Bank shelf edge to lagoon. Significant coral cover was restricted to fore reef habitat (average cover 11.5% and outer reef flat habitat (2.4% and declined to near zero in habitats of the central lagoon zone. Macroalgae dominated benthic cover in all habitats (average cover: 32.5--48.1% but dominant algal genera differed among habitats. A total of 97 fish species were recorded. The composition of Saba Bank fish assemblages differed among habitat types. Highest fish density and diversity occurred in the outer reef flat, fore reef and inner reef flat habitats. Biomass estimates for commercially valued species in the reef zone (fore reef and reef flat habitats ranged between 52 and 83 g/m(2. The composition of Saba Bank fish assemblages reflects the absence of important nursery habitats, as well as the effects of past fishing. The relatively high abundance of large predatory fish (i.e. groupers and sharks, which is generally considered an indicator of good ecosystem health for tropical reef systems, shows that an intact trophic network is still present on Saba Bank.

  11. POP bioaccumulation in macroinvertebrates of alpine freshwater systems

    Energy Technology Data Exchange (ETDEWEB)

    Bizzotto, E.C.; Villa, S. [Department of Environmental and Landscape Sciences, University of Milano-Bicocca, Piazza della Scienza 1, 20126 Milano (Italy); Vighi, M., E-mail: marco.vighi@unimib.i [Department of Environmental and Landscape Sciences, University of Milano-Bicocca, Piazza della Scienza 1, 20126 Milano (Italy)


    This study serves to investigate the uptake of POPs in the different trophic levels (scrapers, collectors, predators, shredders) of macroinvertebrate communities sampled from a glacial and a non-glacial stream in the Italian Alps. The presented results show that the contaminant concentrations in glacial communities are generally higher compared to those from non-glacial catchments, highlighting the importance of glaciers as temporary sinks of atmospherically transported pollutants. Moreover, the data also suggests that in mountain systems snow plays an important role in influencing macroinvertebrate contamination. The main chemical uptake process to the macroinvertebrates is considered to be bioconcentration from water, as similar contaminant profiles were observed between the different trophic levels. The role of biomagnification/bioaccumulation is thought to be absent or negligible. The enrichment of chemicals observed in the predators is likely to be related to their greater lipid content compared to that of other feeding groups. - Influence of POP release in glacial-fed streams, enhanced by global warming, on pristine aquatic ecosystems.

  12. Macroinvertebrate diversity loss in urban streams from tropical forests. (United States)

    Docile, Tatiana N; Figueiró, Ronaldo; Portela, Clayton; Nessimian, Jorge L


    The increase of human activities in recent years has significantly interfered and affected aquatic ecosystems. In this present study, we investigate the effects of urbanization in the community structure of aquatic macroinvertebrates from Atlantic Forest streams. The sampling was conducted in the mountainous region of the State of Rio de Janeiro, Brazil in 10 urban and 10 preserved streams during the dry season (August-September) of 2012. The streams were characterized for its environmental integrity conditions and physico-chemical properties of water. The macroinvertebrates were sampled on rocky substrates with a kicknet. A total of 5370 individuals were collected from all streams and were distributed among Ephemeroptera, Odonata, Plecoptera, Hemiptera, Megaloptera, Coleoptera, Trichoptera, Lepidoptera, and Diptera. In urban sites, all those orders were found, except Megaloptera, while only Mollusca was not found in preserved streams. We performed a non-metric multidimensional scaling (NMDS) analysis that separated two groups distributed among sites in urban communities and another group outside this area. The dominance was significantly higher at urban sites, while the α diversity and equitability were greater in preserved sites. A canonical correspondence analysis (CCA) was also performed, indicating that most taxa associated with high values of the Habitat Integrity Index (HII) and a few genus of the order Diptera with the high values of ammonia, total nitrogen, associated to streams in urban sites. Urban and preserved streams differ by physical-chemical variables and aquatic macroinvertebrates. In urban streams, there is most dominance, while α diversity and equitability are higher in preserved streams.

  13. Mesophotic reef fish assemblages of the remote St. Peter and St. Paul's Archipelago, Mid-Atlantic Ridge, Brazil (United States)

    Rosa, Marcos Rogerio; Alves, Aline Cristina; Medeiros, Diego Valverde; Coni, Ericka Oliveira Cavalcanti; Ferreira, Camilo Moitinho; Ferreira, Beatrice Padovani; de Souza Rosa, Ricardo; Amado-Filho, Gilberto Menezes; Pereira-Filho, Guilherme Henrique; de Moura, Rodrigo Leão; Thompson, Fabiano Lopes; Sumida, Paulo Yukio Gomes; Francini-Filho, Ronaldo Bastos


    Mesophotic reef fish assemblages (30-90 m depth) of the small and remote St. Peter and St. Paul's Archipelago (SPSPA), Mid-Atlantic Ridge, Brazil, were characterized using remotely operated vehicles. Ordination analyses identified distinct fish assemblages in the upper (30-50 m) and lower (50-90 m) mesophotic zones, the former characterized by high abundances of species that are also abundant at euphotic reefs ( Caranx lugubris, Melichthys niger, Stegastes sanctipauli and Chromis multilineata) and the latter dominated by two mesophotic specialists ( Prognathodes obliquus and Chromis enchrysura). Planktivores dominated fish assemblages, particularly in the upper mesophotic zone, possibly due to a greater availability of zooplankton coming from the colder Equatorial Undercurrent in mesophotic depths of the SPSPA. Turf algae, fleshy macroalgae and scleractinian corals dominated benthic assemblages between 30 and 40 m depth, while bryozoans, black corals and sponges dominated between 40 and 90 m depth. Canonical correspondence analysis explained 74 % of the relationship between environmental characteristics (depth, benthic cover and complexity) and structure of fish assemblages, with depth as the most important independent variable. Juveniles of Bodianus insularis and adults of P. obliquus and C. enchrysura were clearly associated with branching black corals ( Tanacetipathes spp.), suggesting that black corals play key ecological roles in lower mesophotic reefs of the SPSPA. Results from this study add to the global database about mesophotic reef ecosystems (MREs) and provide a baseline for future evaluations of possible anthropogenic and natural disturbances on MREs of the SPSPA.

  14. Using aquatic macroinvertebrate species traits to build test batteries for sediment toxicity assessment: accounting for the diversity of potential biological responses to toxicants. (United States)

    Ducrot, Virginie; Usseglio-Polatera, Philippe; Péry, T Alexandre R R; Mouthon, Jacques; Lafont, Michel; Roger, Marie-Claude; Garric, Jeanne; Férard, Jean-François


    An original species-selection method for the building of test batteries is presented. This method is based on the statistical analysis of the biological and ecological trait patterns of species. It has been applied to build a macroinvertebrate test battery for the assessment of sediment toxicity, which efficiently describes the diversity of benthic macroinvertebrate biological responses to toxicants in a large European lowland river. First, 109 potential representatives of benthic communities of European lowland rivers were selected from a list of 479 taxa, considering 11 biological traits accounting for the main routes of exposure to a sediment-bound toxicant and eight ecological traits providing an adequate description of habitat characteristics used by the taxa. Second, their biological and ecological trait patterns were compared using coinertia analysis. This comparison allowed the clustering of taxa into groups of organisms that exhibited similar life-history characteristics, physiological and behavioral features, and similar habitat use. Groups exhibited various sizes (7-35 taxa), taxonomic compositions, and biological and ecological features. Main differences among group characteristics concerned morphology, substrate preferendum and habitat utilization, nutritional features, maximal size, and life-history strategy. Third, the best representatives of the mean biological and ecological characteristics of each group were included in the test battery. The final selection was composed of Chironomus riparius (Insecta: Diptera), Branchiura sowerbyi (Oligochaeta: Tubificidae), Lumbriculus variegatus (Oligochaeta: Lumbriculidae), Valvata piscinalis (Gastropoda: Valvatidae), and Sericostoma personatum (Trichoptera: Sericostomatidae). This approach permitted the biological and ecological variety of the battery to be maximized. Because biological and ecological traits of taxa determine species sensitivity, such maximization should permit the battery to better account

  15. Effects of sewage on benthic invertebrates in the lake of Zurich

    Energy Technology Data Exchange (ETDEWEB)

    Lubini-Ferlin, V.


    In 1981-83 sublittoral macroinvertebrates were collected by means of SCUBA diving from artificial substrates submerged near the outfalls from eight sewage treatment plants in Lake Zurich. Pollution around the outfall resulted on the one hand in a reduction of pollution intolerant benthic invertebrates, on the other hand in a considerable increase in the relative abundance of pollution tolerant taxa such as leeches, flatworms and crustaceans. Changes in the faunal composition were related to nutrient enrichment and changes in the nature of the substratum due to sedimentation of sewage sludge. Species diversity (Simpson index) showed low values near the outfall from some plants, high values near the outfall from others. Low species diversity did not always mark the sites where greatest pollution has been observed.

  16. Bioaccumulation of mercury in benthic communities of a river ecosystem affected by mercury mining. (United States)

    Zizek, Suzana; Horvat, Milena; Gibicar, Darija; Fajon, Vesna; Toman, Mihael J


    The presence of mercury in the river Idrijca (Slovenia) is mainly due to 500 years of mercury mining in this region. In order to understand the cycling of mercury in the Idrijca ecosystem it is crucial to investigate the role of biota. This study is part of an ongoing investigation of mercury biogeochemistry in the river Idrijca, focusing on the accumulation and speciation of mercury in the lower levels of the food chain, namely filamentous algae, periphyton and macroinvertebrates. Mercury analysis and speciation in the biota and in water were performed during the spring, summer and autumn seasons at four locations on the river, representing different degrees of mercury contamination. Total (THg) and methyl mercury (MeHg) were measured. The results showed that the highest THg concentrations in biota correlate well with THg levels in sediments and water. The level of MeHg is spatially and seasonally variable, showing higher values at the most contaminated sites during the summer and autumn periods. The percentage of Hg as MeHg increases with the trophic level from water (0.1-0.8%), algae (0.5-1.3%), periphyton (1.6-8.8%) to macroinvertebrates (0.1-100%), which indicates active transformation, accumulation and magnification of mercury in the benthic organism of this heavily contaminated torrential river.

  17. Effects of water exchange and vegetation on the macroinvertebrate fauna composition of shallow land-uplift bays in the Baltic Sea (United States)

    Hansen, Joakim P.; Wikström, Sofia A.; Kautsky, Lena


    Shallow bays with soft sediment bottoms are common habitats along the Swedish and Finnish Baltic Sea coastline. These bays undergo a process of geomorphometric evolution with the natural isostatic land-uplift process, whereby open bays and sounds decrease in depth and are gradually isolated from the sea, forming bays with narrow openings. This study tested the relationship between the morphometric isolation of the bays from the sea and the macroinvertebrate fauna community of these bays. Additionally, we tested the specific role of the submerged vegetation as an indicator of the macroinvertebrate fauna community. We chose two environmental factors for the analyses, water exchange of the bays and the taxon richness of the macroflora in the bays. We found a hierarchical relationship between water exchange, flora taxon richness, and fauna biomass and taxon richness using structural equation modelling: decreased biomass and taxon richness of fauna were related to decreased flora taxon richness, which in turn was related to decreased water exchange. Using multivariate redundancy analysis, the two environmental factors included in the model were found to explain 47.7% of the variation in the fauna taxon composition and 57.5% of the variation in the functional feeding groups of the fauna. Along the morphometric isolation gradient of the bays, the fauna assemblages changed from a community dominated by gastropods, bivalves, and crustaceans, to a community mainly consisting of a few insect taxa. Moreover, the proportion of predators, gathering collectors, and shredders increased while that of filtering collectors and scrapers decreased. Our results indicate that the density and taxon richness of macroinvertebrate fauna are higher in less morphometrically isolated bays than in more isolated bays in the Baltic Sea. Furthermore, we suggest that the taxon richness of macroflora can serve as an indicator of the fauna community.

  18. A Europe-wide system for assessing the quality of rivers using macroinvertebrates: the AQEM Project* and its importance for southern Europe (with special emphasis on Italy

    Directory of Open Access Journals (Sweden)

    Joanna L. KEMP


    Full Text Available The AQEM Project aims to develop a Europe-wide system for monitoring the ecological quality of rivers using macroinvertebrates, to satisfy the requirements of the EU Water Framework Directive. Three main types of anthropogenic perturbation are being investigated: morphological degradation, water (organic pollution and acidification (the last is not under investigation in Italy. The selection of reference and impaired study sites is discussed. Particular attention is paid to the problems encountered when defining reference conditions. The initial stages of the project highlighted the lack of a Europe-wide definition of river types. The future development of such a typology from the AQEM database is discussed. The standard AQEM data gathering methods are presented, from background information about sites to the microhabitat-based macroinvertebrate sampling method. The extended fieldwork methods used in Italy are described. These included the separate analysis of the invertebrate assemblages from each replicate, the recording of additional microhabitat variables for each replicate and the completion of large-scale survey techniques for each site (including RHS. The extended method was designed to enhance the important ecological information available from the dataset, particularly relevant in Italy where significant gaps exist in the taxonomic and ecological knowledge of many macroinvertebrate taxa. Preliminary and expected findings are presented, including examples of the range and habitat selection of two species of Ephemeroptera endemic to Italy, as well as data relating to the number of taxa found at a site with increasing numbers of microhabitat replicates taken. The importance of the AQEM Project not only for biomonitoring, but also for ecology, taxonomy and conservation, in Italy and for the south of Europe in general, is emphasised.

  19. Fuzzy rule-based macroinvertebrate habitat suitability models for running waters

    NARCIS (Netherlands)

    Broekhoven, Van E.; Adriaenssens, V.; Baets, De B.; Verdonschot, P.F.M.


    A fuzzy rule-based approach was applied to a macroinvertebrate habitat suitability modelling problem. The model design was based on a knowledge base summarising the preferences and tolerances of 86 macroinvertebrate species for four variables describing river sites in springs up to small rivers in t

  20. Benthic foraminifera at the Cretaceous-Tertiary boundary around the Gulf of Mexico (United States)

    Alegret, Laia; Molina, Eustoquio; Thomas, Ellen


    Cretaceous-Tertiary (K-T) boundary sections in northeastern Mexico contain marly formations separated by a controversial clastic unit. Benthic foraminifera in seven sections indicate middle and lower bathyal depths of deposition for the marls, with the exception of the upper bathyal northernmost section. Mixed neritic-bathyal faunas were present in the clastic unit, indicating redeposition in the deep basin by mass-wasting processes resulting from the K-T bolide impact in the Gulf of Mexico. Benthic foraminifera in the Mexican sections, and at other deep-sea locations, were not subject to major extinction at the time of impact, but there were temporary changes in assemblage composition. Benthic faunas indicate well- oxygenated bottom waters and mesotrophic conditions during the late Maastrichtian and increased food supply during the latest Maastrichtian. The food supply decreased drastically just after the K-T boundary, possibly because of the collapse of surface productivity. Cretaceous and early Paleogene benthic foraminifera, however, did not exhibit the benthic-pelagic coupling of present-day faunas, as documented by the lack of significant extinction at the K-T collapse of surface productivity. Much of the food supplied to the benthic faunas along this continental margin might have been refractory material transported from land or shallow coastal regions. The decrease in food supply at the K-T boundary might be associated with the processes of mass wasting, which removed surface, food-rich sediment. Benthic faunas show a staggered pattern of faunal recovery in the lowermost Paleogene, consistent with a staged recovery of the vertical organic flux but also with a gradual buildup of organic matter in the sediment.

  1. Influence of landscape structure on reef fish assemblages (United States)

    Grober-Dunsmore, R.; Frazer, T.K.; Beets, J.P.; Lindberg, W.J.; Zwick, P.; Funicelli, N.A.


    Management of tropical marine environments calls for interdisciplinary studies and innovative methodologies that consider processes occurring over broad spatial scales. We investigated relationships between landscape structure and reef fish assemblage structure in the US Virgin Islands. Measures of landscape structure were transformed into a reduced set of composite indices using principal component analyses (PCA) to synthesize data on the spatial patterning of the landscape structure of the study reefs. However, composite indices (e.g., habitat diversity) were not particularly informative for predicting reef fish assemblage structure. Rather, relationships were interpreted more easily when functional groups of fishes were related to individual habitat features. In particular, multiple reef fish parameters were strongly associated with reef context. Fishes responded to benthic habitat structure at multiple spatial scales, with various groups of fishes each correlated to a unique suite of variables. Accordingly, future experiments should be designed to test functional relationships based on the ecology of the organisms of interest. Our study demonstrates that landscape-scale habitat features influence reef fish communities, illustrating promise in applying a landscape ecology approach to better understand factors that structure coral reef ecosystems. Furthermore, our findings may prove useful in design of spatially-based conservation approaches such as marine protected areas (MPAs), because landscape-scale metrics may serve as proxies for areas with high species diversity and abundance within the coral reef landscape. ?? 2007 Springer Science+Business Media B.V.

  2. Pleistocene oceanographie changes indicated by deep sea benthic foraminifera in the northern Indian Ocean (United States)

    Rai, Ajai K.; Srinivasan, M. S.


    An attempt has been made to understand the Pleistocene bottom water history in response to the paleoclimatic changes in the northern Indian Ocean employing quantitative analyses of deep sea benthic foraminifera at the DSDP sites 219 and 238. Among the 150 benthic foraminifera recorded a few species show dominance with changing percent frequencies during most of the sequence. The dominant benthic foraminiferal assemblages suggest that most of the Pleistocene bottom waters at site 219 and Early Pleistocene bottom waters at site 238 are of North Indian Deep Water (NIDW) origin. However, Late Pleistocene assemblage at site 238 appears to be closely associated with a water mass intermediate between North Indian Deep Water (NIDW) and Antarctic Bottom Water (AABW). Uvigerina proboscidea is the most dominant benthic foraminiferal species present during the Pleistocene at both the sites. A marked increase in the relative abundance of U. proboscidea along with less diverse and equitable fauna during Early Pleistocene suggests a relative cooling, an intensified oceanic circulation and upwelling of nutrient rich bottom waters resulting in high surface productivity. At the same time, low sediment accumulation rate during Early Pleistocene reveals increased winnowing of the sediments possibly due to more corrosive and cold bottom waters. The Late Pleistocene in general, is marked by relatively warm and stable bottom waters as reflected by low abundance of U. proboscidea and more diverse and equitable benthic fauna. The lower depth range for the occurrence of Bulimina aculeate in the Indian Ocean is around 2300 m, similar to that of many other areas. B. aculeata also shows marked increase in its abundance near the Pliocene/Pleistocene boundary while a sudden decrease in the relative abundance of Stilostomella lepidula occurs close to the Early/Late Pleistocene boundary.

  3. Public Sphere as Digital Assemblage

    DEFF Research Database (Denmark)

    Salovaara-Moring, Inka

    the 1990s onwards digitalization brought concepts of network and complexity into the theoretical discourse. This relational turn changed the social ontology of the public sphere into a dynamic and complex system, erasing the division between the fields of reality (the world), representation (discourse...... theories. Drawing from Deleuze & Guattari (1987), Bennett (2010), and Latour (2004) in order to imagine post-human assemblages of public sphere, this paper argues for a relational ontology that emphasizes the complex interactions of political assemblages. Empirically, it draws from the author’s studies......Normative theories of public sphere have struggled with the topic of materiality. The historical narrative of the ‘public sphere’ situated the phenomenon in specific spaces, where practices (public deliberation) and language (discourse) constructed political agencies, and further publics. From...

  4. Dissolved organic carbon concentration controls benthic primary production: results from in situ chambers in north-temperate lakes (United States)

    Godwin, Sean C.; Jones, Stuart E.; Weidel, Brian C.; Solomon, Christopher T.


    We evaluated several potential drivers of primary production by benthic algae (periphyton) in north-temperate lakes. We used continuous dissolved oxygen measurements from in situ benthic chambers to quantify primary production by periphyton at multiple depths across 11 lakes encompassing a broad range of dissolved organic carbon (DOC) and total phosphorous (TP) concentrations. Light-use efficiency (primary production per unit incident light) was inversely related to average light availability (% of surface light) in 7 of the 11 study lakes, indicating that benthic algal assemblages exhibit photoadaptation, likely through physiological or compositional changes. DOC alone explained 86% of the variability in log-transformed whole-lake benthic production rates. TP was not an important driver of benthic production via its effects on nutrient and light availability. This result is contrary to studies in other systems, but may be common in relatively pristine north-temperate lakes. Our simple empirical model may allow for the prediction of whole-lake benthic primary production from easily obtained measurements of DOC concentration.

  5. Low level off-road vehicle (ORV) traffic negatively impacts macroinvertebrate assemblages at sandy beaches in south-western Australia. (United States)

    Davies, Rebecca; Speldewinde, Peter C; Stewart, Barbara A


    Off-road vehicle use is arguably one of the most environmentally damaging human activities undertaken on sandy beaches worldwide. Existing studies focused on areas of high traffic volumes have demonstrated significantly lower abundance, diversity and species richness of fauna in zones where traffic is concentrated. The impact of lower traffic volumes is unknown. This study aimed to investigate the impacts of relatively low-level vehicle traffic on sandy beach fauna by sampling invertebrate communities at eight beaches located in south-western Australia. We found that even low-level vehicle traffic negatively impacts the physical beach environment, and consequently, the ability of many species to survive in this habitat in the face of this disturbance. Compaction, rutting and displacement of the sand matrix were observed over a large area, resulting in significant decreases in species diversity and density, and measurable shifts in community structure on beaches that experienced off-road vehicle traffic. Communities at impact sites did not display seasonal recovery as traffic was not significantly different between seasons. Given a choice between either reducing traffic volumes, or excluding ORV traffic from beaches, our results suggest that the latter would be more appropriate when the retention of ecological integrity is the objective.

  6. Effects of microplastics on European flat oysters, Ostrea edulis and their associated benthic communities. (United States)

    Green, Dannielle Senga


    Plastic pollution is recognised as an emerging threat to aquatic ecosystems, with microplastics now the most abundant type of marine debris. Health effects caused by microplastics have been demonstrated at the species level, but impacts on ecological communities remain unknown. In this study, impacts of microplastics on the health and biological functioning of European flat oysters (Ostrea edulis) and on the structure of associated macrofaunal assemblages were assessed in an outdoor mesocosm experiment using intact sediment cores. Biodegradable and conventional microplastics were added at low (0.8 μg L(-1)) and high (80 μg L(-1)) doses in the water column repeatedly for 60 days. Effects on the oysters were minimal, but benthic assemblage structures differed and species richness and the total number of organisms were ∼1.2 and 1.5 times greater in control mesocosms than in those exposed to high doses of microplastics. Notably, abundances of juvenile Littorina sp. (periwinkles) and Idotea balthica (an isopod) were ∼2 and 8 times greater in controls than in mesocosms with the high dose of either type of microplastic. In addition, the biomass of Scrobicularia plana (peppery furrow shell clam) was ∼1.5 times greater in controls than in mesocosms with the high dose of microplastics. This work indicates that repeated exposure to high concentrations of microplastics could alter assemblages in an important marine habitat by reducing the abundance of benthic fauna.

  7. [Functional feeding groups of macroinvertebrates in Gaira river, Colombia]. (United States)

    Rodríguez-Barrios, Javier; Ospina-Tórres, Rodulfo; Turizo-Correa, Rodrigo


    Tropical rivers are frequently described on their biodiversity but few studies have considered the ecological value of this richness in their food webs. We determined the trophic structure of aquatic macroinvertebrate communities (expressed in the richness and abundance of taxa and biomass proportions of different functional feeding groups) at the level of the river, stretch and microhabitats (functional units - UFs). We evaluated the spatial and temporal variation of these descriptors during wet and dry events, and selected three sites associated with different altitudinal belts. We reported 109 taxa, with 11167 individuals who contributed 107.11g of biomass. Density of macroinvertebrates was favored with increasing height, and biomass showed the opposite pattern (K-W = 10.1, d.f. = 1, p shredders (Macrobrachium, 73%), present only in the lower reaches, followed by shredder Leptonema with 15%, located mostly in the upper reaches and predatory stoneflies of the genus Anacroneuria to 6.56%, which dominated in the middle stretch of stream. Excluding Macrobrachium from the analysis, there was dominance of Anacroneuria in the lower reaches. Between rainfall and drought events, biomass of functional feeding groups was higher in rain (W = 10.1, d.f. = 1, p < 0.05), favoring the growth of decapods, but the abundance was much higher during drought events.

  8. Patterns of Macroinvertebrate and Fish Diversity in Freshwater Sulphide Springs

    Directory of Open Access Journals (Sweden)

    Ryan Greenway


    Full Text Available Extreme environments are characterised by the presence of physicochemical stressors and provide unique study systems to address problems in evolutionary ecology research. Sulphide springs provide an example of extreme freshwater environments; because hydrogen sulphide’s adverse physiological effects induce mortality in metazoans even at micromolar concentrations. Sulphide springs occur worldwide, but while microbial communities in sulphide springs have received broad attention, little is known about macroinvertebrates and fish inhabiting these toxic environments. We reviewed qualitative occurrence records of sulphide spring faunas on a global scale and present a quantitative case study comparing diversity patterns in sulphidic and adjacent non-sulphidic habitats across replicated river drainages in Southern Mexico. While detailed studies in most regions of the world remain scarce, available data suggests that sulphide spring faunas are characterised by low species richness. Dipterans (among macroinvertebrates and cyprinodontiforms (among fishes appear to dominate the communities in these habitats. At least in fish, there is evidence for the presence of highly endemic species and populations exclusively inhabiting sulphide springs. We provide a detailed discussion of traits that might predispose certain taxonomic groups to colonize sulphide springs, how colonizers subsequently adapt to cope with sulphide toxicity, and how adaptation may be linked to speciation processes.

  9. Cross shelf benthic biodiversity patterns in the Southern Red Sea

    KAUST Repository

    Ellis, Joanne


    The diversity of coral reef and soft sediment ecosystems in the Red Sea has to date received limited scientific attention. This study investigates changes in the community composition of both reef and macrobenthic communities along a cross shelf gradient. Coral reef assemblages differed significantly in species composition and structure with location and depth. Inner shelf reefs harbored less abundant and less diverse coral assemblages with higher percentage macroalgae cover. Nutrient availability and distance from the shoreline were significantly related to changes in coral composition and structure. This study also observed a clear inshore offshore pattern for soft sediment communities. In contrast to the coral reef patterns the highest diversity and abundance of soft sediment communities were recorded at the inshore sites, which were characterized by a higher number of opportunistic polychaete species and bivalves indicative of mild disturbance. Sediment grain size and nutrient enrichment were important variables explaining the variability. This study aims to contribute to our understanding of ecosystem processes and biodiversity in the Red Sea region in an area that also has the potential to provide insight into pressing topics, such as the capacity of reef systems and benthic macrofaunal organisms to adapt to global climate change.

  10. Hydro-acoustic remote sensing of benthic biological communities on the shallow South East Australian continental shelf (United States)

    Rattray, Alex; Ierodiaconou, Daniel; Laurenson, Laurie; Burq, Shoaib; Reston, Marcus


    Information regarding the composition and extent of benthic habitats on the South East Australian continental shelf is limited. In this habitat mapping study, multibeam echosounder (MBES) data are integrated with precisely geo-referenced video ground-truth data to quantify benthic biotic communities at Cape Nelson, Victoria, Australia. Using an automated decision tree classification approach, 5 representative biotic groups defined from video analysis were related to hydro-acoustically derived variables in the Cape Nelson survey area. Using a combination of multibeam bathymetry, backscatter and derivative products produced highest overall accuracy (87%) and kappa statistic (0.83). This study demonstrates that decision tree classifiers are capable of integrating variable data types for mapping distributions of benthic biological assemblages, which are important in maintaining biodiversity and other system services in the marine environment.

  11. The effects of fire severity on macroinvertebrate detritivores and leaf litter decomposition. (United States)

    Buckingham, Sebastian; Murphy, Nick; Gibb, Heloise


    High severity wildfire events are a feature of forests globally and are likely to be more prevalent with climate change. As a disturbance process, fire has the potential to change important ecological functions, such as decomposition, through its impact on biodiversity. Despite the recognised importance of decomposition in terms of fuel loads and energy flow, little is known about the post-fire effects of fire severity on decomposition by litter-dwelling macroinvertebrate detritivores. We tested the hypotheses that: 1) increasing fire severity is associated with decreased rates of leaf litter decomposition by macroinvertebrate detritivores; and 2) the abundance and biomass of macroinvertebrate detritivores decreases with increasing fire severity, while body size increases. We used a litterbag experiment at long-unburnt, ground-burnt and crown-burnt sites (n = 7 for all treatments) to test the effect of fire severity on: a) macroinvertebrate-driven break-down of litter fuel loads; and b) the size and abundance of macroinvertebrate detritivores three years after fire. Microhabitat conditions differed among fire severity classes. Macroinvertebrate exclusion reduced litter decomposition by 34.7%. Macroinvertebrate detritivores were larger and less abundant following higher severity fires, possibly as a result of fire-induced changes in habitat structure. Opposing effects of fire severity on macroinvertebrate abundance and body size resulted in both similar detritivore biomass and, most interestingly, no differences in leaf litter decomposition under different fire severities. This suggests that the diversity of macroinvertebrates enhances functional resilience of litter decomposition to fire and that litter-breakdown is not inhibited within three years following a high severity fire in this forest type and where recolonisation sources are readily available. We found no support for the hypothesis that high severity fires reduce litter decomposition and therefore

  12. Widespread kelp-derived carbon in pelagic and benthic nearshore fishes suggested by stable isotope analysis (United States)

    von Biela, Vanessa R.; Newsome, Seth D.; Bodkin, James L.; Kruse, Gordon H.; Zimmerman, Christian E.


    Kelp forests provide habitat for diverse and abundant fish assemblages, but the extent to which kelp provides a source of energy to fish and other predators is unclear. To examine the use of kelp-derived energy by fishes we estimated the contribution of kelp- and phytoplankton-derived carbon using carbon (δ13C) and nitrogen (δ15N) isotopes measured in muscle tissue. Benthic-foraging kelp greenling (Hexagrammos decagrammus) and pelagic-foraging black rockfish (Sebastes melanops) were collected at eight sites spanning ∼35 to 60°N from the California Current (upwelling) to Alaska Coastal Current (downwelling) in the northeast Pacific Ocean. Muscle δ13C values were expected to be higher for fish tissue primarily derived from kelp, a benthic macroalgae, and lower for tissue primarily derived from phytoplankton, pelagic microalgae. Muscle δ13C values were higher in benthic-feeding kelp greenling than in pelagic-feeding black rockfish at seven of eight sites, indicating more kelp-derived carbon in greenling as expected. Estimates of kelp carbon contributions ranged from 36 to 89% in kelp greenling and 32 to 65% in black rockfish using carbon isotope mixing models. Isotopic evidence suggests that these two nearshore fishes routinely derive energy from kelp and phytoplankton, across coastal upwelling and downwelling systems. Thus, the foraging mode of nearshore predators has a small influence on their ultimate energy source as energy produced by benthic macroalgae and pelagic microalgae were incorporated in fish tissue regardless of feeding mode and suggest strong and widespread benthic-pelagic coupling. Widespread kelp contributions to benthic- and pelagic-feeding fishes suggests that kelp energy provides a benefit to nearshore fishes and highlights the potential for kelp and fish production to be linked.

  13. Mussel colonization of a high flow artificial benthic habitat: byssogenesis holds the key. (United States)

    Rajagopal, S; Venugopalan, V P; van der Velde, G; Jenner, H A


    Water flow is an important characteristic determining the settlement and growth of macro-invertebrates in the marine environment. Intake systems of coastal power stations offer a unique opportunity to study the effect of water flow on benthic organisms under field conditions. The cooling water intake system of a tropical coastal power station is used as an experimental facility to study the effect of flow on the recruitment and growth of three mussel species, viz, Brachidontes variabilis, B. striatulus, and Modiolus philippinarum. The study was prompted by earlier observation that these mussels were numerically abundant in the biofouling community present inside the seawater intake tunnel of the power station, even though their occurrence in the benthic community in the coastal waters outside was only nominal. Recruitment data showed that the three mussel species very successfully colonised surfaces exposed to the intake mouth (characterised by relatively high flow) of the power station. Significant difference was observed in the recruitment recorded at the intake point and the ambient environment outside. Under high flow condition, the growth rates of all the three mussel species were uniformly enhanced. It is argued that recruitment of the different species is related to the number of byssus threads produced by each mussel and the strength of the byssus threads. The results indicate that byssus number and byssus strength of the mussels are important criteria that decide successful colonization and establishment in high flow environments.

  14. Viral infections stimulate the metabolism and shape prokaryotic assemblages in submarine mud volcanoes. (United States)

    Corinaldesi, Cinzia; Dell'Anno, Antonio; Danovaro, Roberto


    Mud volcanoes are geological structures in the oceans that have key roles in the functioning of the global ecosystem. Information on the dynamics of benthic viruses and their interactions with prokaryotes in mud volcano ecosystems is still completely lacking. We investigated the impact of viral infection on the mortality and assemblage structure of benthic prokaryotes of five mud volcanoes in the Mediterranean Sea. Mud volcano sediments promote high rates of viral production (1.65-7.89 × 10(9) viruses g(-1) d(-1)), viral-induced prokaryotic mortality (VIPM) (33% cells killed per day) and heterotrophic prokaryotic production (3.0-8.3 μgC g(-1) d(-1)) when compared with sediments outside the mud volcano area. The viral shunt (that is, the microbial biomass converted into dissolved organic matter as a result of viral infection, and thus diverted away from higher trophic levels) provides 49 mgC m(-2) d(-1), thus fuelling the metabolism of uninfected prokaryotes and contributing to the total C budget. Bacteria are the dominant components of prokaryotic assemblages in surface sediments of mud volcanoes, whereas archaea dominate the subsurface sediment layers. Multivariate multiple regression analyses show that prokaryotic assemblage composition is not only dependant on the geochemical features and processes of mud volcano ecosystems but also on synergistic interactions between bottom-up (that is, trophic resources) and top-down (that is, VIPM) controlling factors. Overall, these findings highlight the significant role of the viral shunt in sustaining the metabolism of prokaryotes and shaping their assemblage structure in mud volcano sediments, and they provide new clues for our understanding of the functioning of cold-seep ecosystems.

  15. Impacts of discarded plastic bags on marine assemblages and ecosystem functioning. (United States)

    Green, Dannielle Senga; Boots, Bas; Blockley, David James; Rocha, Carlos; Thompson, Richard


    The accumulation of plastic debris is a global environmental problem due to its durability, persistence, and abundance. Although effects of plastic debris on individual marine organisms, particularly mammals and birds, have been extensively documented (e.g., entanglement and choking), very little is known about effects on assemblages and consequences for ecosystem functioning. In Europe, around 40% of the plastic items produced are utilized as single-use packaging, which rapidly accumulate in waste management facilities and as litter in the environment. A range of biodegradable plastics have been developed with the aspiration of reducing the persistence of litter; however, their impacts on marine assemblages or ecosystem functioning have never been evaluated. A field experiment was conducted to assess the impact of conventional and biodegradable plastic carrier bags as litter on benthic macro- and meio-faunal assemblages and biogeochemical processes (primary productivity, redox condition, organic matter content, and pore-water nutrients) on an intertidal shore near Dublin, Ireland. After 9 weeks, the presence of either type of bag created anoxic conditions within the sediment along with reduced primary productivity and organic matter and significantly lower abundances of infaunal invertebrates. This indicates that both conventional and biodegradable bags can rapidly alter marine assemblages and the ecosystem services they provide.

  16. Quantitative paleobathymetry using oxygen isotopes and shape changes in benthic foraminifera

    Energy Technology Data Exchange (ETDEWEB)

    Gary, A.C.; Williams, D.F.; Healy-Williams, N.


    Accurate estimates of paleodepth are of critical importance to oil exploration in determining environment of deposition and geologic history. Models based on the test shape and the /sup 18/O//sup 16/O ratio in benthic foraminifera from the northwestern Gulf of Mexico indicate that a resolution of +/- 75 ft can be achieved in paleobathymetric reconstructions. The proportion of /sup 18/O and /sup 16/O incorporated into the tests of benthic foraminifera varies with bottom water temperature in a predictable manner. This depth/temperature relationship is the result of the temperature dependence of oxygen isotopic fractionation between sea water and calcium carbonate, and it allows the tests of benthic foraminifera to be used as indicators of paleotemperature. Since subbottom water temperatures on the outer shelf and slope decrease systematically with increasing water depth, these paleotemperatures can be used to reconstruct paleobathymetric trends. Paleobathymetric interpretations can also be independently inferred from Fourier shape analysis of benthic foraminiferal species. Combining the oxygen isotope and shape relationships relative to water depth increases the resolution of paleobathymetric reconstructions and provides an independent check on interpretations based on faunal assemblages and sedimentological data. These paleodepth models should allow extinct taxa to be used for paleobathymetric reconstructions as well.

  17. Effects of sediment-spiked lufenuron on benthic macroinvertebrates in outdoor microcosms and single-species toxicity tests

    NARCIS (Netherlands)

    Brock, T.C.M.; Bas, D.A.; Belgers, J.D.M.; Bibbe, L.; Boerwinkel, M.C.; Crum, S.J.H.; Diepens, N.J.; Kraak, M.H.S.; Vonk, J.A.; Roessink, I.


    Sediment ecotoxicity studies were conducted with lufenuron to (i) complement the results of a water-spiked mesocosm experiment with this lipophilic benzoylurea insecticide, (ii) to explore the predictive value of laboratory single-species tests for population and community-level responses of bent

  18. Fish, Benthic-Macroinvertebrate, and Stream-Habitat Data From Two Estuaries Near Galveston Bay, Texas, 2000-2001 (United States)


    Lepidoptera 0 1 4 0 0 0 11 0 12 0 28 Odonata Anisoptera 0 0 24 0 0 0 0 0 0 0 24 Aphylla sp. 0 1 0 0 0 0 0 0 0 0 1 Argia sp. 4 0 0 0 0 0 0 0 0 0 4... Odonata Coenagrionidae Coenagrion/Enallagma sp. 0 0 16 0 0 0 0 0 0 0 16 Coenagrionidae 10 1 78 0 0 0 189 0 19 0 297 Enallagma sp. 0 0 0 0 0 0 0 0 2 0 2...ARM02 QMH ARM02 DTH ARM03 QMH ARM03 DTH HRSP01 QMH HRSP01 DTH HRSP02 QMH HRSP02 DTH T ab le 4 11 Insecta—Cont. Odonata —Cont. Libellulidae

  19. Evaluating Ethanol-based Sample Preservation to Facilitate Use of DNA Barcoding in Routine Freshwater Biomonitoring Programs Using Benthic Macroinvertebrates (United States)

    Molecular methods, such as DNA barcoding, have the potential in enhance biomonitoring programs worldwide. Altering routinely used sample preservation methods to protect DNA from degradation may pose a potential impediment to application of DNA barcoding and metagenomics for biom...

  20. Effects of Alder Mine on the Water, Sediments, and Benthic Macroinvertebrates of Alder Creek, 1998 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Peplow, Dan


    The Alder Mine, an abandoned gold, silver, copper, and zinc mine in Okanogan County, Washington, produces heavy metal-laden effluent that affects the quality of water in a tributary of the Methow River. The annual mass loading of heavy metals from two audits at the Alder Mine was estimated to exceed 11,000 kg per year. In this study, water samples from stations along Alder Creek were assayed for heavy metals by ICP-AES and were found to exceed Washington State's acute freshwater criteria for cadmium (Cd), copper (Cu), selenium (Se), and zinc (Zn).

  1. Occurrence of polycyclic aromatic hydrocarbons below coal-tar-sealed parking lots and effects on stream benthic macroinvertebrate communities

    Energy Technology Data Exchange (ETDEWEB)

    Scoggins, M.; McClintock, N.L.; Gosselink, L.; Bryer, P. [City Austin, Austin, TX (United States)


    Parking-lot pavement sealants recently have been recognized as a major source of polycyclic aromatic hydrocarbons (PAHs) in urban stream sediments in Austin, Texas. Laboratory and field studies have shown that PAHs in sediments can be toxic to aquatic organisms and can degrade aquatic communities. After identifying increases in concentrations of PAHs in sediments below seal-coated parking lots, we investigated whether the increases had significant effects on stream biota in 5 Austin streams. We sampled sediment chemistry and biological communities above and below the point at which stormwater runoff from the parking lots discharged into the streams, thus providing 5 upstream reference sites and 5 downstream treatment sites. Differences between upstream and downstream concentrations of total PAH ranged from 3.9 to 32 mg/kg. Analysis of the species occurrence data from pool and riffle habitats indicated a significant decrease in community health at the downstream sites, including decreases in richness, intolerant taxa, Diptera taxa, and density. In pool sediments, Chironomidae density was negatively correlated with PAH concentrations, whereas Oligochaeta density responded positively to PAH concentrations. In general, pool taxa responded more strongly than riffle taxa to PAHs, but riffle taxa responded more broadly than pool taxa. Increases in PAH sediment-toxicity units between upstream and downstream sites explained decreases in taxon richness and density in pools between upstream and downstream sites.

  2. Assemblage organization in stream fishes: effects of environmental variation and interspecific interactions (United States)

    Grossman, G.D.; Ratajczak, R.E.; Crawford, M. M.; Freeman, Mary C.


    We assessed the relative importance of environmental variation, interspecific competition for space, and predator abundance on assemblage structure and microhabitat use in a stream fish assemblage inhabiting Coweeta Creek, North Carolina, USA. Our study encompassed a ten year time span (1983-1992) and included some of the highest and lowest flows in the last 58 years. We collected 16 seasonal samples which included data on: 1) habitat availability (total and microhabitat) and microhabitat diversity, 2) assemblage structure (i.e., the number and abundances of species comprising a subset of the community), and 3) microhabitat use and overlap. We classified habitat availability data on the basis of year, season, and hydrologic period. Hydrologic period (i.e., pre-drought [PR], drought [D], and post-drought [PO]) represented the temporal location of a sample with respect to a four-year drought that occurred during the study. Hydrologic period explained a greater amount of variance in habitat availability data than either season or year. Total habitat availability was significantly greater during PO than in PR or D, although microhabitat diversity did not differ among either seasons or hydrologic periods. There were significantly fewer high-flow events (i.e., > 2.1 m3/s) during D than in either PR or PO periods. We observed a total of 16 species during our investigation, and the total number of species was significantly higher in D than in PR samples. Correlation analyses between the number of species present (total and abundant species) and environmental data yielded limited results, although the total number of species was inversely correlated with total habitat availability. A cluster analysis grouped assemblage structure samples by hydrologic period rather than season or year, supporting the contention that variation in annual flow had a strong impact on this assemblage. The drought had little effect on the numerical abundance of benthic species in this assemblage

  3. Benthic Trophic Interactions in an Antarctic Shallow Water Ecosystem Affected by Recent Glacier Retreat. (United States)

    Pasotti, Francesca; Saravia, Leonardo Ariel; De Troch, Marleen; Tarantelli, Maria Soledad; Sahade, Ricardo; Vanreusel, Ann


    The western Antarctic Peninsula is experiencing strong environmental changes as a consequence of ongoing regional warming. Glaciers in the area are retreating rapidly and increased sediment-laden meltwater runoff threatens the benthic biodiversity at shallow depths. We identified three sites with a distinct glacier-retreat related history and different levels of glacial influence in the inner part of Potter Cove (King George Island, South Shetland Islands), a fjord-like embayment impacted since the 1950s by a tidewater glacier retreat. We compared the soft sediment meio- and macrofauna isotopic niche widths (δ13C and δ15N stable isotope analysis) at the three sites to investigate possible glacier retreat-related influences on benthic trophic interactions. The isotopic niches were locally shaped by the different degrees of glacier retreat-related disturbance within the Cove. Wider isotopic niche widths were found at the site that has become ice-free most recently, and narrower niches at the older ice-free sites. At an intermediate state of glacier retreat-related disturbance (e.g. via ice-growler scouring) species with different strategies could settle. The site at the earliest stage of post-retreat development was characterized by an assemblage with lower trophic redundancy. Generally, the isotopic niche widths increased with increasing size spectra of organisms within the community, excepting the youngest assemblage, where the pioneer colonizer meiofauna size class displayed the highest isotopic niche width. Meiofauna at all sites generally occupied positions in the isotopic space that suggested a detrital-pool food source and/or the presence of predatory taxa. In general ice scour and glacial impact appeared to play a two-fold role within the Cove: i) either stimulating trophic diversity by allowing continuous re-colonization of meiofaunal species or, ii) over time driving the benthic assemblages into a more compact trophic structure with increased

  4. Benthic Trophic Interactions in an Antarctic Shallow Water Ecosystem Affected by Recent Glacier Retreat.

    Directory of Open Access Journals (Sweden)

    Francesca Pasotti

    Full Text Available The western Antarctic Peninsula is experiencing strong environmental changes as a consequence of ongoing regional warming. Glaciers in the area are retreating rapidly and increased sediment-laden meltwater runoff threatens the benthic biodiversity at shallow depths. We identified three sites with a distinct glacier-retreat related history and different levels of glacial influence in the inner part of Potter Cove (King George Island, South Shetland Islands, a fjord-like embayment impacted since the 1950s by a tidewater glacier retreat. We compared the soft sediment meio- and macrofauna isotopic niche widths (δ13C and δ15N stable isotope analysis at the three sites to investigate possible glacier retreat-related influences on benthic trophic interactions. The isotopic niches were locally shaped by the different degrees of glacier retreat-related disturbance within the Cove. Wider isotopic niche widths were found at the site that has become ice-free most recently, and narrower niches at the older ice-free sites. At an intermediate state of glacier retreat-related disturbance (e.g. via ice-growler scouring species with different strategies could settle. The site at the earliest stage of post-retreat development was characterized by an assemblage with lower trophic redundancy. Generally, the isotopic niche widths increased with increasing size spectra of organisms within the community, excepting the youngest assemblage, where the pioneer colonizer meiofauna size class displayed the highest isotopic niche width. Meiofauna at all sites generally occupied positions in the isotopic space that suggested a detrital-pool food source and/or the presence of predatory taxa. In general ice scour and glacial impact appeared to play a two-fold role within the Cove: i either stimulating trophic diversity by allowing continuous re-colonization of meiofaunal species or, ii over time driving the benthic assemblages into a more compact trophic structure with

  5. Boron in Pariette Wetland Sediments, Aquatic Vegetation & Benthic Organisms (United States)

    Vasudeva, P.; Jones, C. P.; Powelson, D.; Jacobson, A. R.


    The Pariette Wetlands are comprised of 20 ponds located in Utah's Uintah Basin. Boron concentration in the Pariette Wetlands have been observed to exceed the total maximum daily limit of 750 µg L-1. Considering water flow in and out of the wetlands, boron is accumulating within the wetlands where it is sorbed to sediments and bioconcentrated by wetland plant and macro invertebrates. Since boron is an avian teratogen, an estimate of boron ingestion exposure is warranted. Samples from 3 of the 23 Pariette Wetland ponds with one pond near the inlet, one near the outlet, and one in the middle were collected. Five sampling points were designated along a 100 m transect of each pond. At each sampling point duplicate (or triplicate) samples of water, sediments, benthic organisms and wetland vegetation were collected. The sediments were collected with a KB-corer and divided at depths of 0-2 cm, 2-7 cm, and 7+ cm from the sediment surface. Sample splits were sent to the USU Bug lab for identification of invertebrate species. Whenever this transect was not intercepting vegetation, 2-3 additional sample sites were identified at the pond within stands of representative vegetation where bird nests are located. The plant parts used for boron analyses will include seeds, shoot and roots of vascular plants, as well as algae or duckweeds skimmed from the surface. Samples were processed within 2 days of collection. Water samples filtered through a 0.45 μ membrane filter were analyzed for DOC, pH and ECe. The dried and washed vegetation samples were ground and stored. The benthic organisms and macro invertebrates were netted at the water surface. The dried samples were weighed, ground and stored. Samples were weighed, oven dried and reweighed. For plant and macro-invertebrate samples, a nitric and hydrogen peroxide digestion procedure is used to dissolve environmentally available elements. The Hot Water extraction and DTPA-Sorbitol extraction were compared to estimate wetland plant

  6. Fish, macroinvertebrate, and habitat survey of three Willapa National Wildlife Refuge streams (United States)

    US Fish and Wildlife Service, Department of the Interior — In September and October 2003, staff from the Columbia River Fisheries Program Office (CRFPO) conducted fish, macroinvertebrate, and habitat surveys of three small,...

  7. Living benthic foraminifera as an environmental proxy in coastal ecosystems: A case study from the Aegean Sea (Greece, NE Mediterranean) (United States)

    Koukousioura, Olga; Dimiza, Margarita D.; Triantaphyllou, Maria V.; Hallock, Pamela


    The species composition of the epiphytic benthic foraminiferal fauna was compared at two coastal locations in the Aegean Sea. Samples were collected during August 2001 and July 2003 along the southeastern coast of Andros Island at Korthi Gulf, where there are minimal anthropogenic activities, and at Kastro Gulf, with substantial anthropogenic influence. This study represents the first application of the FORAM Index (FI), which is a single-metric index for water quality originally developed for western Atlantic reef foraminiferal assemblages, to Mediterranean assemblages. Multivariate analyses distinguished three clusters of sample sites representing three foraminiferal assemblages. Samples dominated by the mixotrophic species, A. lobifera, were collected primarily from sites along the northern coasts of both gulfs. Characteristics of this assemblage, including relatively high dominance (D = 0.27-0.51), lower Shannon-Wiener diversity (H' = 1.3-2.1) and high FI (6.6-8.2), all reflect oligotrophic environmental conditions typical of pristine waters of the Aegean Sea. A. lobifera was typically the most common species in the second assemblage, though relative abundances of heterotrophic taxa were higher, resulting in somewhat higher diversity (H' = 1.6-2.4) and lower dominance (D = 0.14-0.36). These indices, as well as the FI range of 3.5-7.0 indicated somewhat more prevalent organic carbon resources but still relatively high water quality. This assemblage was found along the southern coast of Korthi Gulf and at more interior sites in northern Kastro Gulf. The third assemblage was dominated by smaller heterotrophic species, including notable proportions of the stress-tolerant taxa Ammonia spp. and Elphidium spp., and had few or no A. lobifera. Diversity (H' = 1.4-2.0) and dominance (D = 0.22-0.47) indices were similar to those for the first assemblage, but FI values were much lower (2.0-3.4). Samples characterized by this assemblage were collected only from the southern

  8. Temporally variable macroinvertebrate-stone relationships in streams

    DEFF Research Database (Denmark)

    Jacobsen, D.


    Stones were used to sample macroinvertebrates and characterise microhabitats at monthly or bimonthly intervals in six Ecuadorian streams covering a gradient in four different stability measures and other stream characteristics. The physical variables current velocity, water depth, horizontal...... of families vs. individuals) were related to the physical characteristics of individual stone habitats. My second objective was to quantify temporal variability in fauna-stone relationships and to analyse if such variability was related to overall stability of stream reaches. Partial Least Squares (PLS......) multiple regression analyses showed high temporal variability between sampling dates in factor loadings of specific stone micro habitat variables. In spite of this, there was a clear negative effect of depth and a positive effect of current on density and number of families. Stone size was consistently...

  9. Macro-invertebrate decline in surface water polluted with imidacloprid.

    Directory of Open Access Journals (Sweden)

    Tessa C Van Dijk

    Full Text Available Imidacloprid is one of the most widely used insecticides in the world. Its concentration in surface water exceeds the water quality norms in many parts of the Netherlands. Several studies have demonstrated harmful effects of this neonicotinoid to a wide range of non-target species. Therefore we expected that surface water pollution with imidacloprid would negatively impact aquatic ecosystems. Availability of extensive monitoring data on the abundance of aquatic macro-invertebrate species, and on imidacloprid concentrations in surface water in the Netherlands enabled us to test this hypothesis. Our regression analysis showed a significant negative relationship (P<0.001 between macro-invertebrate abundance and imidacloprid concentration for all species pooled. A significant negative relationship was also found for the orders Amphipoda, Basommatophora, Diptera, Ephemeroptera and Isopoda, and for several species separately. The order Odonata had a negative relationship very close to the significance threshold of 0.05 (P = 0.051. However, in accordance with previous research, a positive relationship was found for the order Actinedida. We used the monitoring field data to test whether the existing three water quality norms for imidacloprid in the Netherlands are protective in real conditions. Our data show that macrofauna abundance drops sharply between 13 and 67 ng l(-1. For aquatic ecosystem protection, two of the norms are not protective at all while the strictest norm of 13 ng l(-1 (MTR seems somewhat protective. In addition to the existing experimental evidence on the negative effects of imidacloprid on invertebrate life, our study, based on data from large-scale field monitoring during multiple years, shows that serious concern about the far-reaching consequences of the abundant use of imidacloprid for aquatic ecosystems is justified.

  10. [Studies on Latin American freshwater macroinvertebrates: recent advances and future directions]. (United States)

    Ramírez, Alonso; Gutiérrez-Fonseca, Pablo E


    Latin America is an active scientific research area, in particular with respect to the study of freshwater macroinvertebrates. The present serves as an introduction to a special issue that highlights recent research projects on macroinvertebrates in Latin America. As part of this introduction, we conducted a literature analysis of the last 14 years of publications from the region that highlights the steady increase in publications on macroinvertebrates. Most studies from 2000-2013 were conducted in Brazil, Colombia, Argentina, and Costa Rica, and were focused on taxonomy and different issues related to biodiversity and distribution. There was a tendency for the use of local low-impact journals, but high impact publications were also found. This special issue contributes with 18 studies conducted in eight different countries. Two major topics are covered in the special issue, the ecology and natural history of aquatic macroinvertebrates and their use in the evaluation of anthropogenic impacts to aquatic ecosystems. Based on the literature review and contributions included in the issue, we discuss research needs for the region. Identified needs include: (1) to continue emphasizing taxonomic research, (2) assess mechanisms responsible for changes in biodiversity, (3) assess the role of macroinvertebrates in ecosystem processes and function, (4) improve biomonitoring efforts beyond unimetric indices, (5) the need for an ecosystem perspective, and (6) establishing long-term studies. This special issue is an initial effort to advance our knowledge on freshwater macroinvertebrates in Latin America.

  11. Early invasion population structure of quagga mussel and associated benthic invertebrate community composition on soft sediment in a large reservoir (United States)

    Wittmann, Marion E.; Chandra, Sudeep; Caires, Andrea; Denton, Marianne; Rosen, Michael R.; Wong, Wai Hing; Teitjen, Todd; Turner, Kent; Roefer, Peggy; Holdren, G. Chris


    In 2007 an invasive dreissenid mussel species, Dreissena bugensis (quagga mussel), was discovered in Lake Mead reservoir (AZ–NV). Within 2 years, adult populations have spread throughout the lake and are not only colonizing hard substrates, but also establishing in soft sediments at depths ranging from 1 to >100 m. Dreissena bugensis size class and population density distribution differs between basins; cluster analysis revealed 5 adult cohorts within Boulder Basin and Overton Arm but low densities and low cohort survival in the Las Vegas Basin. Regression analysis suggests depth and temperature are not primary controllers of D. bugensis density in Lake Mead, indicating other factors such as sediment type, food availability or other resource competition may be important. Monthly veliger tows showed at least 2 major spawning events per year, with continuous presence of veligers in the water column. Adult mussels have been found in spawn or post-spawn condition in soft sediments in shallow to deep waters (>80 m) indicating the potential for reproduction at multiple depths. Comparisons to a 1986 benthic survey suggest there have been shifts in nondreissenid macroinvertebrate composition; however, it is unclear if this is due to D. bugensis presence. Current distribution of nondreissenid macroinvertebrates is heterogeneous in all 3 basins, and their biodiversity decreased when D. bugensis density was 2500/m2 or greater.

  12. Patterns of Assemblage Structure Indicate a Broader Conservation Potential of Focal Amphibians for Pond Management.

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    Elin Soomets

    Full Text Available Small freshwater ponds host diverse and vulnerable biotic assemblages but relatively few conspicuous, specially protected taxa. In Europe, the amphibians Triturus cristatus and Pelobates fuscus are among a few species whose populations have been successfully restored using pond restoration and management activities at the landscape scale. In this study, we explored whether the ponds constructed for those two target species have wider conservation significance, particularly for other species of conservation concern. We recorded the occurrence of amphibians and selected aquatic macro-invertebrates (dragonflies; damselflies; diving beetles; water scavenger beetles in 66 ponds specially constructed for amphibians (up to 8 years post construction and, for comparison, in 100 man-made ponds (created by local people for cattle or garden watering, peat excavation, etc. and 65 natural ponds in Estonia. We analysed nestedness of the species assemblages and its dependence on the environment, and described the co-occurrence patterns between the target amphibians and other aquatic species. The assemblages in all ponds were significantly nested, but the environmental determinants of nestedness and co-occurrence of particular species differed among pond types. Constructed ponds were most species-rich irrespective of the presence of the target species; however, T. cristatus was frequent in those ponds and rare elsewhere, and it showed nested patterns in every type of pond. We thus conclude that pond construction for the protected amphibians can serve broader habitat conservation aims in the short term. However, the heterogeneity and inconsistent presence of species of conservation concern observed in other types of ponds implies that long-term perspectives on pond management require more explicit consideration of different habitat and biodiversity values. We also highlight nestedness analysis as a tool that can be used for the practical task of selecting focal

  13. Multiscale patterns in the diversity and organization of benthic intertidal fauna among French Atlantic estuaries (United States)

    Blanchet, Hugues; Gouillieux, Benoît; Alizier, Sandrine; Amouroux, Jean-Michel; Bachelet, Guy; Barillé, Anne-Laure; Dauvin, Jean-Claude; de Montaudouin, Xavier; Derolez, Valérie; Desroy, Nicolas; Grall, Jacques; Grémare, Antoine; Hacquebart, Pascal; Jourde, Jérôme; Labrune, Céline; Lavesque, Nicolas; Meirland, Alain; Nebout, Thiebaut; Olivier, Frédéric; Pelaprat, Corine; Ruellet, Thierry; Sauriau, Pierre-Guy; Thorin, Sébastien


    Based on a parallel sampling conducted during autumn 2008, a comparative study of the intertidal benthic macrofauna among 10 estuarine systems located along the Channel and Atlantic coasts of France was performed in order to assess the level of fauna similarity among these sites and to identify possible environmental factors involved in the observed pattern at both large (among sites) and smaller (benthic assemblages) scales. More precisely this study focused on unraveling the observed pattern of intertidal benthic fauna composition and diversity observed at among-site scale by exploring both biotic and abiotic factors acting at the among- and within-site scales. Results showed a limited level of similarity at the among-site level in terms of intertidal benthic fauna composition and diversity. The observed pattern did not fit with existing transitional water classification methods based on fish or benthic assemblages developed in the frame of the European Water Framework Directive (WFD). More particularly, the coastal plain estuaries displayed higher among-site similarity compared to ria systems. These coastal plain estuaries were characterized by higher influence of river discharge, lower communication with the ocean and high suspended particulate matter levels. On the other hand, the ria-type systems were more dissimilar and different from the coastal plain estuaries. The level of similarity among estuaries was mainly linked to the relative extent of the intertidal “Scrobicularia plana-Cerastoderma edule” and “Tellina tenuis” or “Venus” communities as a possible consequence of salinity regime, suspended matter concentrations and fine particles supply with consequences on the trophic functioning, structure and organization of benthic fauna. Despite biogeographical patterns, the results also suggest that, in the context of the WFD, these estuaries should only be compared on the basis of the most common intertidal habitat occurring throughout all

  14. Marine Invertebrate assemblages in southern California (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This is a point file of invertebrate site clusters calculated from benthic trawls completed by the Southern California Coastal Water Research Project (SCCWRP). Data...

  15. Nearshore marine fish assemblages in southern California (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Fish benthic trawls were completed by the Southern California Coastal Water Research Project (SCCWRP). Data from 425 fisheries independent trawls ranging from 2-215...

  16. Associations Between Macroinvertebrates and Paralemanea mexicana, an Endemic Freshwater Red Alga from a Mountain River in Central Mexico. (United States)

    Caro-Borrero, A; Carmona-Jiménez, J


    Macrophytes are common inhabitants of lotic environments and, depending on their morphological traits, possess adaptations that provide shelter to aquatic invertebrates against strong river flow and predators. They may also be used as a food source by macroinvertebrates. The main goal of this study was to determine the relationship between the red alga Paralemanea mexicana and its role as a shelter and/or food source for lotic macroinvertebrates. We also conducted research on the role of microhabitat and morphological variations of the alga in determining macroinvertebrate taxon abundance, diversity, and functional group composition in a high-current velocity river. Results showed that changes in cover and morphology of P. mexicana were mostly correlated with river current velocity, irradiance, and seasonal variation. In turn, these were related to changes in abundance and diversity of the associated macroinvertebrate community. In addition, six macroinvertebrate functional feeding groups were evaluated for associations with the red alga: filtering and gathering collectors, piercers, scrapers, herbivore shredders, and predators. The results showed that the Trichoptera Hydroptilidae genera Ochrotrichia and Metrichia use P. mexicana as a food source and case-building material. The Trichoptera Glossosomatidae Mortoniella uses the alga as a substrate. The biotic interactions between P. mexicana and associated macroinvertebrates reveal the importance of macrophytes as purveyors of substrate, as food and shelter for macroinvertebrates, and also as promoters of macroinvertebrate community diversity. In addition, it was shown that macroinvertebrate herbivory likely facilitates vegetative propagation of the red alga through increased release and germination of carpospores and new gametophytes.

  17. Mechanisms of temporary adhesion in benthic animals

    NARCIS (Netherlands)

    Dodou, D.; Breedveld, P.; Winter, J.C.F.; Dankelman, J.; Leeuwen, van J.L.


    Adhesive systems are ubiquitous in benthic animals and play a key role in diverse functions such as locomotion, food capture, mating, burrow building, and defence. For benthic animals that release adhesives, surface and material properties and external morphology have received little attention compa

  18. Near-field receiving water monitoring of trace metals and a benthic community near the Palo Alto Regional Water Quality Control Plant in South San Francisco Bay, California-2010 (United States)

    Dyke, Jessica; Parcheso, Francis; Thompson, Janet K.; Cain, Daniel J.; Luoma, Samuel N.; Hornberger, Michelle I.


    Trace-metal concentrations in sediment and in the clam Macoma petalum (formerly reported as Macoma balthica), clam reproductive activity, and benthic macroinvertebrate community structure were investigated in a mudflat 1 kilometer south of the discharge of the Palo Alto Regional Water Quality Control Plant (PARWQCP) in South San Francisco Bay, Calif. This report includes the data collected for the period January 2010 to December 2010 and extends a critical long-term biogeochemical record that dates back to 1974. These data serve as the basis for the City of Palo Alto's Near-Field Receiving Water Monitoring Program initiated in 1994.

  19. Near-field receiving water monitoring of trace metals and a benthic community near the Palo Alto Regional Water Quality Control Plant in south San Francisco Bay, California; 2015 (United States)

    Cain, Daniel J.; Thompson, Janet K.; Crauder, Jeffrey; Parchaso, Francis; Stewart, Robin; Turner, Matthew A.; Hornberger, Michelle I.; Luoma, Samuel N.


    Trace-metal concentrations in sediment and in the clam Macoma petalum (formerly reported as Macoma balthica), clam reproductive activity, and benthic macroinvertebrate community structure were investigated in a mudflat 1 kilometer south of the discharge of the Palo Alto Regional Water Quality Control Plant (PARWQCP) in South San Francisco Bay, California. This report includes data collected by U.S. Geological Survey (USGS) scientists for the period from January 2015 to December 2015. These data are appended to long-term datasets extending back to 1974, and serve as the basis for the City of Palo Alto’s Near-Field Receiving Water Monitoring Program, initiated in 1994.

  20. Diets and trophic-guild structure of a diverse fish assemblage in Chesapeake Bay, U.S.A. (United States)

    Buchheister, A; Latour, R J


    Dietary habits and trophic-guild structure were examined in a fish assemblage (47 species) of the Chesapeake Bay estuary, U.S.A., using 10 years of data from >25 000 fish stomachs. The assemblage was comprised of 10 statistically significant trophic guilds that were principally differentiated by the relative amounts of Mysida, Bivalvia, Polychaeta, Teleostei and other Crustacea in the diets. These guilds were broadly aggregated into five trophic categories: piscivores, zooplanktivores, benthivores, crustacivores and miscellaneous consumers. Food web structure was largely dictated by gradients in habitat (benthic to pelagic) and prey size. Size classes within piscivorous species were more likely to be classified into different guilds, reflecting stronger dietary changes through ontogeny relative to benthivores and other guilds. Relative to predator species and predator size, the month of sampling had negligible effects on dietary differences within the assemblage. A majority of sampled fishes derived most of their nutrition from non-pelagic prey sources, suggesting a strong coupling of fish production to benthic and demersal food resources. Mysida (predominantly the opossum shrimp Neomysis americana) contributed substantially to the diets of over 25% of the sampled predator groups, indicating that this species is a critical, but underappreciated, node in the Chesapeake Bay food web.

  1. Evaluating regional differences in macroinvertebrate communities from forested depressional wetlands across eastern and central North America.

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    Batzer, Darold, P.; Dietz-Brantley, Susan E.; Taylor, Barbera E.; DeBiase, Adrienne E.


    Batzer, Darold, P., Susan E. Dietz-Brantley, Barbera E. Taylor, and Adrienne E. DeBiase. 2005. Evaluating regional differences in macroinvertebrate communities from forested depressional wetlands across eastern and central North America. J. N. Am. Benthol. Soc. 24(2):403-414. Abstract. Forested depressional wetlands are an important seasonal wetland type across eastern and central North America. Macroinvertebrates are crucial ecosystem components of most forested depressional wetlands, but community compositions can vary widely across the region. We evaluated variation in macroinvertebrate faunas across eastern and central North America using 5 published taxa lists from forested depressional wetlands in Michigan, Ontario, Wisconsin, Florida, and Georgia. We supplemented those data with quantitative community descriptions generated from 17 forested depressional wetlands in South Carolina and 74 of these wetlands in Minnesota. Cluster analysis of presence/absence data from these 7 locations indicated that distinct macroinvertebrate communities existed in northern and southern areas. Taxa characteristic of northern forested depressionalwetlands included Sphaeriidae, Lumbriculidae, Lymnaeidae, Physidae, Limnephilidae, Chirocephalidae, and Hirudinea (Glossophoniidae and/or Erpodbellidae) and taxa characteristic of southern sites included Asellidae, Crangonyctidae, Noteridae, and Cambaridae. Quantitative sampling in South Carolina and Minnesota indicated that regionally characteristic taxa included some of the most abundant organisms, with Sphaeriidae being the 2nd most abundant macroinvertebrate in Minnesota wetlands and Asellidae being the 2nd most abundant macroinvertebrate in South Carolina wetlands. Mollusks, in general, were restricted to forested depressional wetlands of northern latitudes, a pattern that may reflect a lack of Ca needed for shell formation in acidic southern sites. Differences in community composition probably translate into region

  2. Macroinvertebrate Trophic Groups in an Andean Wetland of Colombia

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    John Jader Rivera Usme


    Full Text Available In the wetland Jaboque (Bogotá, Colombia the physical and chemical properties of the water and the food dietary guilds of the aquatic macroinvertebrate community were analyzed from April 2009 to January 2010. The wetland waters had a slightly acid character with high values of nitrate, ammonia and orthophosphate, so this ecosystem is classified as eutrophic to hypereutrophic.In the aquatic macroinvertebrate community six food groups were recorded; they were conformed by 27 families, 26 confirmed genera and nine to be confirmed, with a total of 6,403 individuals collected in 28 samples of macrophytes. The highest abundances corresponded to detritivores (43.5 %, collector-scrapers (31.5 %, and collector-shredders (14.1 %, which were more abundantin the months of low rainfall. Stomach contents of some of the organisms showed that most of these individuals consumed more than one food type and high amounts of organic matter. Detrended correspondence analysis (DCA showed a spatial (stations and temporal (climatic seasons organization, in which trophic guilds are grouped according to their niche requirements, environmental fluctuations or anthropogenic factors. Variations in dietary groups reflected changes in the macroinvertebrate community from a functional perspective and indicated that the wetland is very disturbed by urban activities.GRUPOS TRÓFICOS DE MACROINVERTEBRADOS ACUÁTICOS EN UN HUMEDAL URBANO ANDINO DE COLOMBIAEn el humedal Jaboque (Bogotá, Colombia se analizaron las condiciones físicas y químicas del agua y se estudió la comunidad de macroinvertebrados acuáticos por grupos dietarios entre abril de 2009 y enero de 2010. Las aguas del humedal presentaron un carácter ligeramente ácido con valores altos de nitratos, nitrógeno amoniacal y fósforo, por lo que este ecosistema se clasificacomo eutrófico a hipereutrófico. La comunidad de macroinvertebrados acuáticos registró seis grupos alimenticios, los cuales

  3. Quantifying the responses of biological indices to rare macroinvertebrate taxa exclusion: Does excluding more rare taxa cause more error? (United States)

    Yu, Zhengda; Wang, Hui; Meng, Jiao; Miao, Mingsheng; Kong, Qiang; Wang, Renqing; Liu, Jian


    Including or excluding rare taxa in bioassessment is a controversial topic, which essentially affects the reliability and accuracy of the result. In the present paper, we hypothesize that biological indices such as Shannon-Wiener index, Simpson's index, Margalef index, evenness, BMWP (biological monitoring working party), and ASPT (Average Score Per Taxon) respond differently to rare taxa exclusion. To test this hypothesis, a benthic macroinvertebrate data set based on recent fifteen-year studies in China was built for suppositional plot analyses. A field research was conducted in the Nansi Lake to perform related analyses. The results of suppositional plot simulations showed that Simpson's index placed more weight on common taxa than any other studied indices, followed by Shannon-Wiener index which remained a high value with the exclusion of rare taxa. The results indicated that there was not much of effect on Simpson's index and Shannon-Wiener index when rare taxa were excluded. Rare taxa played an important role in Margalef index and BMWP than in other indices. Evenness showed an increase trend, while ASPT varied inconsistently with the exclusion of rare taxa. Results of the field study also indicated that rare taxa had few impacts on the Shannon-Wiener index. By examining the relationships between the rare taxa and biological indices in our study, it is suggested that including the rare taxa when using BMWP and excluding them in the proposed way (e.g., fixed-count subsampling) to calculate Shannon-Wiener index and Simpson's index could raise the efficiency and reduce the biases in the bioassessment of freshwater ecosystems.

  4. Environmental changes during the Paleocene–Eocene Thermal Maximum in Spitsbergen as reflected by benthic foraminifera

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    Jenö Nagy


    Full Text Available The study deals with environmental changes during the Paleocene–Eocene Thermal Maximum (PETM and its background conditions in Spitsbergen through analysis of benthic foraminiferal assemblages (FA in a section drilled in the Paleogene Central Basin. The impact of this extreme global warming occurs here in prodelta shelf mudstones composing the lower part of the Gilsonryggen Member (Frysjaodden Formation. The start of the PETM perturbation is marked by a faunal turnover, in which the medium-diversity circumpolar Reticulophragmium assemblage was replaced by a low-diversity Trochammina fauna. During the hyperthermal period, benthic foraminiferal diversity decreased severely, while the dominance of small-sized taxa with epifaunal morphology strongly increased. This low-diversity fauna occurs in sediments with a reduced thorium/uranium ratio (proxy for oxygenation and kaolinite enrichment (proxy for high humidity. The faunal changes were thus caused by the combined effects of hypoxic and hyposaline conditions in a stratified water column, due to extreme warming with its accompanying intensified hydrologic cycle. The PETM acme coincides with the maximum flooding surface (MFS of the Gilsonryggen depositional sequence, composed of the Gilsonryggen Member and the overlying Battfjellet and Aspelintoppen formations. The transgressive phase of the sequence was initiated by local tectonics, while the eustatic sea-level rise of the PETM was superimposed on this transgression.To access the supplementary material for this article, please see supplementary files under Article Tools online.

  5. Benthic foraminiferal bathymetry and sea-bed biogeochemistry in the Gulf of Mexico

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    Loubere, P. (Northern Illinois Univ., DeKalb, IL (United States). Dept. of Geology); Gary, A. (Unocal, Brea, CA (United States). Science and Technology Div.)


    Box cores were collected down the slope of the northwest Gulf of Mexico so that the sea-bed biogeochemistry could be compared to established benthic Foraminiferal bathymetric zonations. Pore water geochemistry along with water columns and sedimentologic analyses were used to quantify bottom water temperatures, organic carbon flux, bottom water oxygen content and sedimentary environment. The prominent Foraminiferal boundary between 170 and 200m water depth is associated with position of the mud-line in the northwestern Gulf. Deeper than this, assemblage changes are more gradational and, between 200 and 600m, appear related to gradients in temperature, oxygen supply and organic carbon flux. Between 600 and 2,000m bathymetric zonation correlates to the organic carbon flux profile. An analysis of sediment pore water geochemistry and sedimentary features in the box cores shows that there is a progressive change in the vertical distribution and character of potential microhabitats within the sediments down the slope of the northwest Gulf. This gradient in habitats must influence the generation of benthic Foraminiferal assemblages, and it is largely controlled by the organic carbon flux to the sea-bed.

  6. Climate change and glacier retreat drive shifts in an Antarctic benthic ecosystem. (United States)

    Sahade, Ricardo; Lagger, Cristian; Torre, Luciana; Momo, Fernando; Monien, Patrick; Schloss, Irene; Barnes, David K A; Servetto, Natalia; Tarantelli, Soledad; Tatián, Marcos; Zamboni, Nadia; Abele, Doris


    The Antarctic Peninsula (AP) is one of the three places on Earth that registered the most intense warming in the last 50 years, almost five times the global mean. This warming has strongly affected the cryosphere, causing the largest ice-shelf collapses ever observed and the retreat of 87% of glaciers. Ecosystem responses, although increasingly predicted, have been mainly reported for pelagic systems. However, and despite most Antarctic species being benthic, responses in the Antarctic benthos have been detected in only a few species, and major effects at assemblage level are unknown. This is probably due to the scarcity of baselines against which to assess change. We performed repeat surveys of coastal benthos in 1994, 1998, and 2010, analyzing community structure and environmental variables at King George Island, Antarctica. We report a marked shift in an Antarctic benthic community that can be linked to ongoing climate change. However, rather than temperature as the primary factor, we highlight the resulting increased sediment runoff, triggered by glacier retreat, as the potential causal factor. The sudden shift from a "filter feeders-ascidian domination" to a "mixed assemblage" suggests that thresholds (for example, of tolerable sedimentation) and alternative equilibrium states, depending on the reversibility of the changes, could be possible traits of this ecosystem. Sedimentation processes will be increasing under the current scenario of glacier retreat, and attention needs to be paid to its effects along the AP.

  7. Nursery function of coastal temperate benthic habitats: New insight from the bivalve recruitment perspective (United States)

    Barbier, Pierrick; Meziane, Tarik; Forêt, Martin; Tremblay, Réjean; Robert, René; Olivier, Frédéric


    Marine habitat function has been typically investigated in terms of biogeochemical regulation but rarely in terms of population renewal, which is mainly controlled by recruitment dynamics. The recruitment phase is crucial for organisms with a bentho-pelagic life cycle, such as bivalves, and it regulates the population renewal success. This study provides new insight on the role of temperate benthic habitats on bivalve recruitment, as a function of nursery areas. Six dominant benthic habitats of the Chausey archipelago (Normandy, France) were studied. In each habitat, bivalve recruit assemblages were described at the end of two reproductive seasons. Furthermore, Ostrea edulis juveniles were immerged on each habitat during two months to compare growth performances and feeding status, estimated by fatty acid composition. Recruit assemblages differ from each habitat according to sediment grain-size composition and bathymetrical levels. Subtidal habitats, and especially Crepidula fornicata banks and Glycymeris glycymeris coarse sands, supported the highest species abundance and richness of recruits. All O. edulis juveniles fed on the same trophic resources but digestive glands of juveniles from C. fornicata banks were more concentrated in total fatty acids than those from subtidal G. glycymeris coarse sands and maerl banks. Our results depict the key role of subtidal and structured habitats, composed of ecosystem engineers, in enhancing bivalve recruitment and extending the bivalve population renewal. This study suggests that the crucial role of these habitats as bivalve nurseries must be integrated in management perspectives.

  8. Effects of CO2 hydrate on deep-sea foraminiferal assemblages

    Energy Technology Data Exchange (ETDEWEB)

    Ricketts, E. R.; Kennett, J. P.; Hill, T. M.; Barry, J. P.


    This study, conducted with the Monterey Bay Aquarium Research Institute (MBARI), is the first to investigate potential effects of carbon dioxide (CO2) hydrates on benthic microfossils, specifically oraminifera. The experiment was conducted in September 2003 aboard the R/V Western Flier using the ROV Tiburon. Experimental (CO2 exposed) and control cores were collected at 3600m and stained to distinguish live (stained) from dead (unstained) individuals. Foraminifera are ideal for these investigations because of differing test composition (calcareous and agglutinated) and thickness, and diverse epifaunal and infaunal depth preferences. The effects of the CO2 on assemblages have been tracked both vertically (10cm depth) and horizontally, and between live and dead individuals. Increased mortality and dissolution of calcareous forms resulted from exposure to CO2 hydrate. Preliminary results suggest several major effects on surface sediment assemblages: 1) total number of foraminifera in a sample decreases; 2) foraminiferal diversity decreases in both stained and unstained specimens. The number of planktonic and hyaline calcareous tests declines greatly, with milliolids being more resistant to dissolution when stained; and 3) percentage of stained (live) forms is higher. Down-core trends (up to 10cm) indicate: 1) percent agglutinated forms decline and calcareous forms increasingly dominate; 2) agglutinated diversity decreases with depth; and 3) assemblages become increasingly similar with depth to those in control cores not subjected to CO2 hydrate. These results imply almost complete initial mortality and dissolution upon CO2 hydrate emplacement in the corrals. (Author)

  9. Characteristics of the mesophotic megabenthic assemblages of the vercelli seamount (north tyrrhenian sea.

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    Marzia Bo

    Full Text Available The biodiversity of the megabenthic assemblages of the mesophotic zone of a Tyrrhenian seamount (Vercelli Seamount is described using Remotely Operated Vehicle (ROV video imaging from 100 m depth to the top of the mount around 61 m depth. This pinnacle hosts a rich coralligenous community characterized by three different assemblages: (i the top shows a dense covering of the kelp Laminaria rodriguezii; (ii the southern side biocoenosis is mainly dominated by the octocorals Paramuricea clavata and Eunicella cavolinii; while (iii the northern side of the seamount assemblage is colonized by active filter-feeding organisms such as sponges (sometimes covering 100% of the surface with numerous colonies of the ascidian Diazona violacea, and the polychaete Sabella pavonina. This study highlights, also for a Mediterranean seamount, the potential role of an isolated rocky peak penetrating the euphotic zone, to work as an aggregating structure, hosting abundant benthic communities dominated by suspension feeders, whose distribution may vary in accordance to the geomorphology of the area and the different local hydrodynamic conditions.

  10. Can benthic foraminifera be used as bio-indicators of pollution in areas with a wide range of physicochemical variability? (United States)

    Martins, Maria Virgínia Alves; Pinto, Anita Fernandes Souza; Frontalini, Fabrizio; da Fonseca, Maria Clara Machado; Terroso, Denise Lara; Laut, Lazaro Luiz Mattos; Zaaboub, Noureddine; da Conceição Rodrigues, Maria Antonieta; Rocha, Fernando


    The Ria de Aveiro, a lagoon located in the NW coast of Portugal, presents a wide range of changes to the natural hydrodynamical and physicochemical conditions induced for instance by works of port engineering and pollution. In order to evaluate the response of living benthic foraminifera to the fluctuations in physicochemical parameters and pollution (metals and TOC), eight sediment samples were collected from canals and salt pans within the Aveiro City, in four different sampling events. During the sampling events, salinity showed the most significant fluctuations among the physicochemical parameters with the maximum range of variation at Troncalhada and Santiago salt pans. Species such as Haynesina germanica, Trochammina inflata and Entzia macrescens were found inhabiting these hypersaline environments with the widest fluctuations of physicochemical parameters. In contrast, Ammonia tepida dominated zones with high concentrations of metals and organic matter and in lower salinity waters. Parameters related to benthic foraminiferal assemblages (i.e., diversity and evenness) were found to significantly decline in stations polluted by metals and characterized by higher TOC content. Foraminiferal density reduced significantly in locations with a wide range of physicochemical temporal variability. This work shows that, even under extreme conditions caused by highly variable physicochemical parameters, benthic foraminiferal assemblages might be used as valuable bioindicators of environmental stress.

  11. Short-term effects of visitor trampling on macroinvertebrates in karst streams in an ecotourism region. (United States)

    Escarpinati, Suzana Cunha; Siqueira, Tadeu; Medina-Jr, Paulino Barroso; de Oliveira Roque, Fabio


    In order to evaluate the potential risks of human visitation on macroinvertebrate communities in streams, we investigated the effect of trampling using two short-term experiments conducted in a Brazilian ecotourism karst region. We asked three questions: (a) Does trampling increase the drift rate of aquatic macroinvertebrates and organic matter? (b) Does trampling change the macroinvertebrate community organization? (c) If trampling alters the community structure, is a short time (5 days, a between weekends interval - peaks of tourism activities) sufficient for community restructuring? Analysis of variance of richness, total abundance, abundance of the most abundant genus (e.g., Simothraulopsis and Callibaetis), and community composition showed that trampling immediately affects macroinvertebrate community and that the intervals between the peaks of visitation (5 days) are not sufficient to complete community restructuring. Considering that bathing areas receive thousands of visitors every year and that intervals of time without visitation are nearly nonexistent, we suspect that the negative effects on the macroinvertebrate community occur in a cumulative way. Finally, we discuss some simple procedures that could potentially be used for reducing trampling impacts in lotic environments.

  12. Influence of salinity and prey presence on the survival of aquatic macroinvertebrates of a freshwater marsh (United States)

    Kang, Sung-Ryong; King, Sammy L.


    Salinization of coastal freshwater environments is a global issue. Increased salinity from sea level rise, storm surges, or other mechanisms is common in coastal freshwater marshes of Louisiana, USA. The effects of salinity increases on aquatic macroinvertebrates in these systems have received little attention, despite the importance of aquatic macroinvertebrates for nutrient cycling, biodiversity, and as a food source for vertebrate species. We used microcosm experiments to evaluate the effects of salinity, duration of exposure, and prey availability on the relative survival of dominant aquatic macroinvertebrates (i.e., Procambarus clarkii Girard, Cambarellus puer Hobbs, Libellulidae, Dytiscidae cybister) in a freshwater marsh of southwestern Louisiana. We hypothesized that increased salinity, absence of prey, and increased duration of exposure would decrease survival of aquatic macroinvertebrates and that crustaceans would have higher survival than aquatic insect taxon. Our first hypothesis was only partially supported as only salinity increases combined with prolonged exposure duration affected aquatic macroinvertebrate survival. Furthermore, crustaceans had higher survival than aquatic insects. Salinity stress may cause mortality when acting together with other stressful conditions.

  13. Epigeal and Hypogeal Macroinvertebrate Diversity in Different Microhabitats of the Yusmarg Hill Resort (Kashmir, India

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    Abroo Ali


    Full Text Available Soil macroinvertebrate communities are important within the soil system and contribute to a wide variety of soil processes. A soil study was conducted to assess the composition and diversity of soil macroinvertebrates in Yusmarg hill resort of Kashmir valley at four sites characterised by different types of vegetation and interferences like grazing or fencing, during the months of May, June, November and December 2010. During the study, it was observed that different sites exhibited variations in diversity of both epigeal as well as hypogeal soil macroinvertebrates. For epigeal macroinvertebrates, highest diversity was recorded in forest edge (2.089 and inner forest (2.058 and relatively low diversity in grazed (1.61 and fenced areas (1.09. For hypogeal macroinvertebrates, diversity was recorded highest for inner forest site (2.216 than forest edge (1.9 and relatively lower in fenced (1.22 and grazed (1.21 sites. The physical disturbance in the form of grazing and fencing probably reduce the diversity of the soil macro fauna as is inferred from the present study.

  14. Aquatic macrophyte and macroinvertebrate diversity and conservation in wetlands of the Sinos River basin. (United States)

    Maltchik, L; Rolon, A S; Stenert, C


    Wetlands are important sites for biological conservation because they support rich biodiversity and present high productivity. Species-area relationship is an important tool in conservation planning and it has been extensively used for wetland management. This study had as aims: (1) to analyse macrophyte and macroinvertebrate diversity in the fragmented wetlands of the Sinos River basin; and (2) to investigate whether wetland areas could work as a tool for selecting the important habitats for biodiversity conservation. Throughout the study, 56 species of macrophytes and 57 taxa of macroinvertebrates were identified. Macrophyte richness was related to the wetland area, but macroinvertebrate richness, however, was not related to the wetland area. The macrophyte and macroinvertebrate composition were not related to the wetland area. Species composition varied between the regions of the basin and the difference in the species composition occurred mainly by the distribution of macroinvertebrates. With regard to the biodiversity conservation of the Sinos River basin, the wetland area must not be a priority criterion for choosing the important wetlands for conservation. The environmental policies for biodiversity conservation must include management actions focused also on the protection of small wetlands. Moreover, other criteria should be analysed in further research such as habitat diversity, hydroperiod, geographic distribution and connectivity.

  15. Fish assemblages in southern California kelp forests. (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This is a point file of fish assemblages calculated from diver surveys in kelp forests in Southern California. Visual census data was combined for two separate...

  16. Giardia duodenalis genetic assemblages and hosts

    Directory of Open Access Journals (Sweden)

    Heyworth Martin F.


    Full Text Available Techniques for sub-classifying morphologically identical Giardia duodenalis trophozoites have included comparisons of the electrophoretic mobility of enzymes and of chromosomes, and sequencing of genes encoding β-giardin, triose phosphate isomerase, the small subunit of ribosomal RNA and glutamate dehydrogenase. To date, G. duodenalis organisms have been sub-classified into eight genetic assemblages (designated A–H. Genotyping of G. duodenalis organisms isolated from various hosts has shown that assemblages A and B infect the largest range of host species, and appear to be the main (or possibly only G. duodenalis assemblages that undeniably infect human subjects. In at least some cases of assemblage A or B infection in wild mammals, there is suggestive evidence that the infection had resulted from environmental contamination by G. duodenalis cysts of human origin.

  17. Predictions of mineral assemblages in planetary interiors (United States)

    Stolper, E.


    It is shown that mineral compatibilities in the model system CaO-MgO-Al2O3-SiO2 can be applied to deduce the mineral assemblages expected in planetary interiors and their variation with depth. In general, the available estimates of bulk composition of the terrestrial planets suggest that the terrestrial planets can be divided into two groups based on their predicted mineral assemblages. The terrestrial, Venusian, and lunar bulk compositions are expected to display the following sequence of mineral assemblages with increasing pressure: plagioclase lherzolite, spinel lherzolite, and garnet lherzolite. The sequences expected in Martian and Mercurian are different: spinel-plagioclase wehrlite, spinel lherzolite, and spinel-garnet wehrlite. These assemblages have a major influence on the compositions of liquids produced by melting of these planetary interiors, on the solidus temperatures, and thus on the nature of planetary differentiation and the types of magmas extruded at planetary surfaces.

  18. Assessment of ecological quality of the Tajan river in Iran using a multimetric macroinvertebrate index and species traits

    NARCIS (Netherlands)

    Aazami, J.; Esmaili Sari, A.; Abdoli, A.; Sohrabi, H.; Brink, van den P.J.


    The objectives of this study were to assess the biological water of the Iranian Tajan River using different metrics, i.e., a Multimetric Macroinvertebrate Index (MMI) and a traits-based method. Twenty-eight physico-chemical parameters, 10 habitat factors, and abundance of macroinvertebrates were obt

  19. Assessment of Constructed Wetland Biological Integrity Using Aquatic Macroinvertebrates

    Directory of Open Access Journals (Sweden)

    C. Galbrand


    Full Text Available A surface flow constructed wetland consisting of seven cells was used to treat the leachates from a decommissioned landfill. Wetland monitoring was performed by evaluating the treatment efficiency of the landfill leachate and the wetland biological integrity of the wetland. The water quality samples were analyzed for iron, manganese, phosphorus (orthophosphate, pH, dissolved oxygen (DO, nitrogen (ammonia, nitrate, nitrite and TKN, chemical oxygen demand (COD, total suspended solids (TSS and total dissolved solids (TDS. Aquatic macroinvertebrates were examined using Average Score per Taxon (ASPT via the Biological Monitoring Working Party (BMWP biotic index, the Ephemeroptera, Trichoptera, Sphaeriidae and Odonata (ETSD biotic index, abundance of mayflies and trophic structure. Reductions of 49.66, 66.66, 1.91, 46.37 and 8.33% were obtained for manganese, orthophosphate, TSS, TDS and COD, respectively. The nitrite, dissolved oxygen and iron concentrations were not in accordance with the water quality guidelines for aquatic life. ASPT, ETSD, percent abundance of mayflies and trophic structure represented moderate to moderately-poor water quality in comparison to a high quality reference site. Iron had most adverse effect on the biological system of the wetland.

  20. Ammonite habitat revealed via isotopic composition and comparisons with co-occurring benthic and planktonic organisms (United States)

    Sessa, Jocelyn Anne; Larina, Ekaterina; Knoll, Katja; Garb, Matthew; Cochran, J. Kirk; Huber, Brian T.; MacLeod, Kenneth G.; Landman, Neil H.


    Ammonites are among the best-known fossils of the Phanerozoic, yet their habitat is poorly understood. Three common ammonite families (Baculitidae, Scaphitidae, and Sphenodiscidae) co-occur with well-preserved planktonic and benthic organisms at the type locality of the upper Maastrichtian Owl Creek Formation, offering an excellent opportunity to constrain their depth habitats through isotopic comparisons among taxa. Based on sedimentary evidence and the micro- and macrofauna at this site, we infer that the 9-m-thick sequence was deposited at a paleodepth of 70-150 m. Taxa present throughout the sequence include a diverse assemblage of ammonites, bivalves, and gastropods, abundant benthic foraminifera, and rare planktonic foraminifera. No stratigraphic trends are observed in the isotopic data of any taxon, and thus all of the data from each taxon are considered as replicates. Oxygen isotope-based temperature estimates from the baculites and scaphites overlap with those of the benthos and are distinct from those of the plankton. In contrast, sphenodiscid temperature estimates span a range that includes estimates of the planktonic foraminifera and of the warmer half of the benthic values. These results suggest baculites and scaphites lived close to the seafloor, whereas sphenodiscids sometimes inhabited the upper water column and/or lived closer to shore. In fact, the rarity and poorer preservation of the sphenodiscids relative to the baculites and scaphites suggests that the sphenodiscid shells may have only reached the Owl Creek locality by drifting seaward after death.

  1. Benthic community composition on submerged reefs in the central Great Barrier Reef (United States)

    Roberts, T. E.; Moloney, J. M.; Sweatman, H. P. A.; Bridge, T. C. L.


    Community dynamics on coral reefs are often examined only in relatively shallow waters, which are most vulnerable to many disturbances. The Great Barrier Reef World Heritage Area (GBRWHA) includes extensive submerged reefs that do not approach sea level and are within depths that support many coral reef taxa that also occur in shallow water. However, the composition of benthic communities on submerged reefs in the GBRWHA is virtually unknown. We examined spatial patterns in benthic community composition on 13 submerged reefs in the central Great Barrier Reef (GBR) at depths of 10-30 m. We show that benthic communities on submerged reefs include similar species groups to those on neighbouring emergent reefs. The spatial distribution of species groups was well explained by depth and cross-shelf gradients that are well-known determinants of community composition on emergent reefs. Many equivalent species groups occurred at greater depths on submerged reefs, likely due to variability in the hydrodynamic environment among reef morphologies. Hard coral cover and species richness were lowest at the shallowest depth (6 m) on emergent reefs and were consistently higher on submerged reefs for any given depth. These results suggest that disturbances are less frequent on submerged reefs, but evidence that a severe tropical cyclone in 2011 caused significant damage to shallow regions of more exposed submerged reefs demonstrates that they are not immune. Our results confirm that submerged reefs in the central GBR support extensive and diverse coral assemblages that deserve greater attention in ecosystem assessments and management decisions.

  2. Assessment of soft-bottom polychaete assemblages in the Gulf of Lions (NW Mediterranean) based on a mesoscale survey (United States)

    Labrune, Céline; Grémare, Antoine; Amouroux, Jean-Michel; Sardá, Rafael; Gil, João; Taboada, Sergi


    Ninety-two stations (10, 20, 30, 40 and 50 m depth) located on 21 inshore-offshore transects between the French-Spanish border and the mouth of the Rhône River were sampled during the 1998 Fall. Their polychaete fauna was analyzed to: (1) describe the distribution pattern of polychaete assemblages at the scale of the whole Gulf of Lions, (2) identify the relationships between these assemblages and the main environmental parameters, (3) establish a link between these assemblages and the benthic communities already described for Northwestern Mediterranean, and (4) assess recent historical changes in trends in densities and α diversity between assemblages. Three polychaete assemblages were identified using cluster analysis and associated procedures. These assemblages were tightly associated with depth and sediment granulometry as indicated by the concordance between their spatial distributions and the sedimentary map of the Gulf of Lions. Assemblage I contained most of the 10 and 20 m deep stations and was associated with littoral fine sands. Assemblage I was found all over the Gulf of Lions and was characterized by high abundance and high biomass due to the presence of large numbers of the serpulid Ditrupa arietina. Assemblage II was mostly composed of 30 m deep stations and was associated with littoral sandy mud. Assemblage II was dominated by the lumbrinerid Lumbrineris latreilli. It was composed of two sub-assemblages (IIa and IIb) in relation with sediment granulometry. Sub-assemblage IIb was associated with finer sediment than sub-assemblage IIa. Sub-assemblage IIa was only found in the Southern part of the Gulf of Lions, whereas sub-assemblage IIb was mostly found in the Northern part of the Gulf of Lions. This pattern is probably indicative of the sedimentation of fine particles originating from the Rhône River at intermediate depth as suggested by: (1) the sedimentary map of the Gulf of Lions, and (2) the outputs of recent models of sediment transport in

  3. Catchment land-use effects on littoral macroinvertebrates in response to local habitat structure and trophic state

    DEFF Research Database (Denmark)

    McGoff, Elaine; Sandin, Leif Leonard


    macroinvertebrate community structure: trophic status, substrate variables or riparian variables. We also investigated what influence each of these groups of variables has on the other. The impact of large scale land use patterns was also investigated, to determine if macroinvertebrates responded differently in two...... different catchment land use types: impaired and unimpaired. Partial canonical ordination analysis showed that substrate variables were the most important for describing macroinvertebrate community variation in both catchment land use classes, followed by riparian descriptors, with the trophic signal only....... The macroinvertebrate community composition was also responding to changes in riparian vegetation, specifically the presence of riparian trees and canopy cover. These variables, or lack of, are possible proxies for anthropogenic alteration of lake shores. Therefore, although macroinvertebrates may not be strong...

  4. Reconstructing pre-impact baseline conditions using benthic foraminifera in an area of increasing petroleum exploration activities (United States)

    Dijkstra, Noortje; Junttila, Juho; Aagaard-Sørensen, Steffen


    While macrofauna is traditionally used to bio-monitor to state of the ecosystem, benthic foraminifera have large potential for bio-monitoring as well. As their tests stay preserved in the sedimentary archive it is possible to reconstruct pre-impacted conditions, by studying foraminiferal assemblages in sediment cores. The use of foraminiferal faunas as bio-monitoring tools is complicated by the natural variability. Therefore, detailed site specific studies are needed, to understand the range of natural variability of the area of interest. This study characterizes the natural variability in the Bjørnøyrenna-Ingøydjupet area in the Southern Barents Sea. The Southern Barents Sea is a relatively un-impacted and uncontaminated area, however petroleum industry related activities are expected to increase in the near future. This makes the area a valuable natural laboratory to establish pre-impacted baselines for future seabed monitoring programs. Benthic foraminiferal assemblages were examined at high resolution in sediment cores and compared to sediment properties and metal concentrations. Species associated to temperate water masses dominate in the southern part of the study area, while species associated to cooler water masses increase in abundance towards the north into Bjørnøyrenna. Additionally, the foraminiferal assemblages might reflect climatic oscillations on both millennial and decadal time scales. Patterns in the calcareous foraminiferal assemblages suggest an enhanced food supply as a result of increased Atlantic Water inflow through the region during the last 150 years. Sediment TOC content has been linked with variable inflow of Atlantic Water. A strong positive correlation was observed between TOC content with metal content in the cores. It is therefore essential to consider the role of natural variability of oceanographic conditions when using benthic foraminiferal assemblages to monitor for potential anthropogenic impacts on the environment. This

  5. Paleoecology of Benthic Foraminifera in Coral Reefs Recorded in the Jurassic Tuwaiq Mountain Formation of the Khashm Al-Qaddiyah Area, Central Saudi Arabia

    Institute of Scientific and Technical Information of China (English)

    Mohamed Youssef; Abdelbaset S El-Sorogy


    Thirty three benthic foraminiferal species belong to 23 genera and 16 families have been recorded from the coral reefs of the Callovian Tuwaiq Formation, Khashm Al-Qaddiyah area, Central Saudi Arabia. Three species:Astacolus qaddiyahensis, Nodosaria riyadhensis, Siderolites jurassica are believed to be new. Nearly all identified foraminifera are of Atlantic-Miditeranean affinity. The fo-raminiferal assemblage recorded in the present work is mixed of open marine, moderately deep ma-rine conditions associations and shallow to deep lagoon. The reefal part of upper Twiaq Formation may have been deposited in shallow water of lower to middle shelf depth (20–50 m) as indicated by abundant corals and benthic foraminifera. The coral fauna and bearing benthic foraminifera indi-cated moderate water energy.

  6. Feasibility of remote sensing benthic microalgae (United States)

    Zingmark, R. G.


    Results of data analyses from multispectral scanning data are presented. The data was collected in July 1977 for concentration of chlorophyll in benthic microalgae (mainly diatoms) on an estuary mudflat.

  7. Benthic Habitats of the Florida Keys (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The benthic habitats of the Florida Keys were mapped from a series of 450 aerial photographs. Ecologists outlined the boundaries of specific habitat types by...


    Benthic macrofaunal samples were collected at random stations in Willapa Bay, WA, in four habitats [eelgrass (Zostera marina), Atlantic cordgrass (Spartina alterniflora), mud shrimp (Upogebia pugettensis), ghost shrimp (Neotrypaea californiensis)] in 1996 and in seven habitats (Z...

  9. Assessment of periphyton, aquatic macrophytes, benthic communities, and physical habitat in midwestern United States streams coinciding with varying historical concentrations of atrazine. (United States)

    Hall, Lenwood W; Anderson, Ronald D; Killen, William D; Hosmer, Alan J; Brain, Richard A


    The objectives of this pilot study were to: (1) characterize periphyton and benthic communities using standard collection methods in six Midwest watersheds with varying historical levels of atrazine (low range, medium range and upper range); (2) qualitatively assess presence of aquatic vascular plants at each site; (3) assess and compare physical habitat at each study site in order to evaluate how physical habitat structure may influence the biological communities and (4) analyze the periphyton and benthic macroinvertebrate community data (i.e., series of metrics) among sites to evaluate possible differences or similarities among sites with different historical atrazine exposures. Five of the eight physical habitat metrics (including total physical habitat score) were different among the six study sites. There appeared to be no substantial difference in the structure of periphtyon communities at the six Midwest sites based on 9 of 12 metrics. For the three metrics that showed differences among sites-percentage of sensitive diatoms, percent Achnanches minutissima and percent motile diatoms - there was no consistent pattern with previous degrees of atrazine exposure and the scoring of these metrics. There were also no statistical differences in aquatic macrophyte spatial coverage among the six study areas. Thus, based on the spatially and temporally limited periphyton and aquatic macrophyte data, varying historical atrazine exposure was not associated with impact on resident plant communities (the target receptor group for atrazine). All 10 benthic community metrics showed significant differences among the six Midwest sites. Although no consistent pattern existed with varying historic levels of atrazine, benthic communities at one site with lower historical levels of atrazine were of higher quality than the other five sites. However, this one site also had a higher quality habitat compared to the other sites which was most likely the reason for this benthic condition.

  10. Coastal Benthic Boundary Layer (CBBL) Research Program (United States)


    Ecologic Atlas of Benthic Foraminifera of the Gulf of Mexico . Marine Science International, Woods Hole, MA, 174 p. Shiller, Alan, M., Brunner, Charlotte A...implications for the preservation of skeletal carbonates. Sedimentology, 45:39-51. Poag, C. Wylie, 1981. Ecologic Atlas of Benthic Foraminifera of the Gulf of...of the inner continental shelf. The shelf of the northeastern Gulf of Mexico is currently sediment-starved with most material deposited by the

  11. Effects of CO2 Hydrate on Deep-Sea Foraminiferal Assemblages

    Energy Technology Data Exchange (ETDEWEB)

    Ricketts, E R; Kennett, J P; Hill, T M; Barry, J P


    THE EFFECTS OF CO2 HYDRATE ON DEEP-SEA FORAMINIFERAL ASSEMBLAGES E. R. Ricketts*, J. P. Kennett and T. M. Hill Department of Geological Sciences University of California, Santa Barbara, CA USA Jim Barry Monterey Bay Aquarium Research Institute Moss Landing, CA USA ABSTRACT This study, conducted with the Monterey Bay Aquarium Research Institute (MBARI), is the first to investigate potential effects of CO2 hydrates on benthic microfossils, specifically foraminifera. The experiment was conducted in September 2003 aboard the R/V Western Flier using the ROV Tiburon. Experimental (CO2 exposed) and control cores were collected at 3600m and stained to distinguish live (stained) from dead (unstained) individuals. Foraminifera are ideal because of differing test composition (calcareous and agglutinated) and thickness, and diverse epifaunal and infaunal depth preferences. The effects of the CO2 on assemblages have been tracked both vertically (10cm depth) and horizontally, and between live and dead individuals. Increased mortality and dissolution of calcareous forms resulted from exposure to CO2 hydrate. Preliminary results suggest several major effects on surface sediment assemblages: 1) total number of foraminifera in a sample decreases; 2) foraminiferal diversity decreases in both stained and unstained specimens. The number of planktonic and hyaline calcareous tests declines greatly, with milliolids being more resistant to dissolution when stained; and 3) percentage of stained (live) forms is higher. Down-core trends (up to 10cm) indicate: 1) percent agglutinated forms decline and calcareous forms increasingly dominate; 2) agglutinated diversity decreases with depth; and 3) assemblages become increasingly similar with depth to those in control cores not subjected to CO2 hydrate. These results imply almost complete initial mortality and dissolution upon CO2 hydrate emplacement.

  12. Diel variability in seawater pH relates to calcification and benthic community structure on coral reefs.

    Directory of Open Access Journals (Sweden)

    Nichole N Price

    Full Text Available Community structure and assembly are determined in part by environmental heterogeneity. While reef-building corals respond negatively to warming (i.e. bleaching events and ocean acidification (OA, the extent of present-day natural variability in pH on shallow reefs and ecological consequences for benthic assemblages is unknown. We documented high resolution temporal patterns in temperature and pH from three reefs in the central Pacific and examined how these data relate to community development and net accretion rates of early successional benthic organisms. These reefs experienced substantial diel fluctuations in temperature (0.78°C and pH (>0.2 similar to the magnitude of 'warming' and 'acidification' expected over the next century. Where daily pH within the benthic boundary layer failed to exceed pelagic climatological seasonal lows, net accretion was slower and fleshy, non-calcifying benthic organisms dominated space. Thus, key aspects of coral reef ecosystem structure and function are presently related to natural diurnal variability in pH.

  13. Benthic foraminifera from two coastal lakes of southern Latium (Italy). Preliminary evaluation of environmental quality. (United States)

    Carboni, Maria Gabriella; Succi, Maria Cristina; Bergamin, Luisa; Di Bella, Letizia; Frezza, Virgilio; Landini, Bruna


    Benthic foraminifera and sediment texture were studied on a total of 37 samples, collected from two brackish-water coastal basins: Fogliano Lake and Lungo Lake (central Italy). The research was performed as a preliminary low-cost survey to highlight the degree of the environmental stress and to recognize a possible anthropogenic disturbance. The sedimentological and foraminiferal data were processed by bivariate and multivariate statistical analysis. Three distinct assemblages, referable to different environments were recognized for the Fogliano Lake: inner, intermediate and outer lagoon. Only the outer lagoon assemblage was found in the Lungo Lake. The distribution of foraminifera in the Fogliano Lake suggests a natural environmental stress probably due to the ecological instability typical of marginal environments, while the absence of the inner and intermediate lagoon assemblages in the Lungo Lake suggests an environmental disturbance possibly related to human activities. An interdisciplinary survey including geochemical analyses is recommended in order to deduce the nature and degree of pollution in the Lungo Lake.

  14. Biomass, species composition and diversity of benthic diatoms in mangroves of the Houyu Bay, China

    Institute of Scientific and Technical Information of China (English)

    CHEN Changping; GAO Yahui; LIN Peng


    The biomass, species composition and diversity of benthic diatom assemblages in mud-flat soils in Kandelia candel (L.) Druce communities with and without vegetation were studied seasonally at the Houyu Bay in Fuding City, Fujian Province, China. A total of 103taxa were identified (including varieties). Eighty-four taxa were found in the mud-flat with vegetation and 74 taxa in the mud-fiat without vegetation, while the biomass was large in January and April and decreased from July to October. The most abundant species in the mud-flat with vegetation are Nitzschia cocconeiformis, Gyrosigma scalproides and N. Fasciculata, compared with G. Scalproides and N.obtusa var. Scalpelliformis in the mud-flat without vegetation. High H' values at 2 sites during all seasons suggest that diatom assemblages in the sediments of the Houyu Bay represent an original environment. Multi-dimensional scaling of diatom assemblages from mud-flats with and without vegetation shows that a slight seasonal change and only a single association occur in the angroves.

  15. Indicator value of lotic water mites (Acari: Hydrachnidia and their use in macroinvertebrate-based indices for water quality assessment purposes

    Directory of Open Access Journals (Sweden)

    Miccoli F. P.


    Full Text Available The Water Framework Directive (WFD of the European Union includes benthic macroinvertebrates for the ecological assessment of running waters. The invertebrate-based Star-ICMi index, adopted in 2010, does not include Hydrachnidia (water mites in its complex formulation. However, Hydrachnidia are associated with many environmental variables and may be useful for stream ecological characterization. We have therefore assessed the bioindicator value of Hydrachnidia in streams of central Italy, and the ability of two mite-containing (the PTH and the newly formulated PTHfam indices and four mite-excluding biotic indices (Star-ICMi, BMWP, ASPT, and IBE to characterize 216 sites ranging from semipristine to impacted. Mite bioindicator value was high at family level. Index reliability was consistently low for the PTH and ASPT indices. Distribution of mite families across quality classes (QCs was fully separated only for the PTHfam index. QC assignment remained reliable at high index values (i.e., at high ecological status for the PTHfam and BMWP indices, while logarithmic correlations between the PTHfam and the other indices suggest that the latter may misrepresent sites in high, good, and moderate ecological status sensu WFD. Further studies on the PTHfam index are warranted in light of its simplicity, high reliability, and low sampling and taxonomic identification effort.

  16. Benthic foraminifera as indicators of habitat change in anthropogenically impacted coastal wetlands of the Ebro Delta (NE Iberian Peninsula). (United States)

    Benito, Xavier; Trobajo, Rosa; Ibáñez, Carles; Cearreta, Alejandro; Brunet, Manola


    Present-day habitats of the Ebro Delta, NE Iberian Peninsula, have been ecologically altered as a consequence of intensive human impacts in the last two centuries (especially rice farming). Benthic foraminiferal palaeoassemblages and sediment characteristics of five short cores were used to reconstruct past wetland habitats, through application of multivariate DCA and CONISS techniques, and dissimilarity coefficients (SCD). The timing of environmental changes was compared to known natural and anthropogenic events in order to identify their possible relationships. In deltaic wetlands under altered hydrological conditions, we found a decrease in species diversity and calcareous-dominated assemblages, and a significant positive correlation between microfaunal changes and organic matter content. Modern analogues supported palaeoenvironmental interpretation of the recent evolution of the Delta wetlands. This research provides the first recent reconstruction of change in the Ebro Delta wetlands, and also illustrates the importance of benthic foraminifera for biomonitoring present and future conditions in Mediterranean deltas.

  17. Wave exposure as a predictor of benthic habitat distribution on high energy temperate reefs

    Directory of Open Access Journals (Sweden)

    Alex eRattray


    Full Text Available The new found ability to measure physical attributes of the marine environment at high resolution across broad spatial scales has driven the rapid evolution of benthic habitat mapping as a field in its own right. Improvement of the resolution and ecological validity of seafloor habitat distribution models has, for the most part, paralleled developments in new generations of acoustic survey tools such as multibeam echosounders. While sonar methods have been well demonstrated to provide useful proxies of the relatively static geophysical patterns that reflect distribution of benthic species and assemblages, the spatially and temporally variable influence of hydrodynamic energy on habitat distribution have been less well studied. Here we investigate the role of wave exposure on patterns of distribution of near-shore benthic habitats. A high resolution spectral wave model was developed for a 624 km2 site along Cape Otway, a major coastal feature of western Victoria, Australia. Comparison of habitat classifications implemented using the Random Forests algorithm established that significantly more accurate estimations of habitat distribution were obtained by including a fine-scale numerical wave model, extended to the seabed using linear wave theory, than by using depth and seafloor morphology information alone. Variable importance measures and map interpretation indicated that the spatial variation in wave induced bottom orbital velocity was most influential in discriminating habitat the classes containing canopy forming kelp Ecklonia radiata, a foundation kelp species that affects biodiversity and ecological functioning on shallow reefs across temperate Australasia. We demonstrate that hydrodynamic models reflecting key environmental drivers on wave exposed coastlines are important in accurately defining distributions of benthic habitats.


    Directory of Open Access Journals (Sweden)



    Full Text Available The Permian sequence of the Transcaucasia, which comprises the Davaly, Asni, Gnishik, Arpa, Khachik, and Akhura Formations, is described. A precise dating of the formations based on the analysis of fusulinid assemblages is also provided. The Davaly Formation corresponds to the Bolorian Stage of the Lower Permian (Cisuralian; the Asni Formation corresponds to the Kubergandian Stage, and to the lower half of the Murgabian Stage of the Middle Permian (Guadalupian; the Gnishik Formation corresponds approximately to the upper half of the Murgabian Stage; and the Arpa and Khachik Formations represent the entire Midian Stage of the Middle Permian. Only the uppermost Chanakhchy Beds of the Khachik Formation are referred to the upper series of the Permian (Lopingian, based on the latest proposal of the International Subcommission on Permian Stratigraphy concerning series boundaries. The Akhura Formation encompasses the Dzhulfian and Dorashamian Stages of the Upper Permian. Refined correlations between the Permian sequence of the Transcaucasia and the most complete Permian sequences of the Tethyan region (Central Iran, southestern Pamirs, South China, Japan are presented. The transgressive overlapping of the Permian deposits is recorded in these areas, similar to the Transcaucasia. Although the transgression began during the Bolorian, it reached the widest extent in the Kubergandian and therefore, in most sections the transgressive series begins with deposits of Kubergandian age. The Middle and Upper Permian deposits of the Transcaucasia, Iran, and southern Turkey belonged to a single carbonate platform. Similar extensive carbonate platforms are recorded in the southern parts of Afghanistan and China. A change in the sedimentary regime was recorded in all these platforms at the boundary between the Guadalupian and Lopingian epochs. The Guadalupian time was marked by the intensive accumulation of biolitithic and detrital limestones produced by benthic

  19. Evaluation of stream ecological integrity using litter decomposition and benthic invertebrates

    Energy Technology Data Exchange (ETDEWEB)

    Castela, Jose [Departamento de Zoologia and IMAR-CIC, Universidade de Coimbra, Largo Marques de Pombal, 3004-517 Coimbra (Portugal)], E-mail:; Ferreira, Veronica [Departamento de Zoologia and IMAR-CIC, Universidade de Coimbra, Largo Marques de Pombal, 3004-517 Coimbra (Portugal)], E-mail:; Graca, Manuel A.S. [Departamento de Zoologia and IMAR-CIC, Universidade de Coimbra, Largo Marques de Pombal, 3004-517 Coimbra (Portugal)], E-mail:


    Biomonitoring programs to access the ecological integrity of freshwaters tend to rely exclusively on structural parameters. Here we evaluated stream ecological integrity using (a) benthic macroinvertebrate derived metrics and a biotic index as measures of structural integrity and (b) oak litter decomposition and associated fungal sporulation rates as measures of functional integrity. The study was done at four sites (S1, S2, S3 and S4) along a downstream increasing phosphorus and habitat degradation gradient in a small stream. The biotic index, invertebrate metrics, invertebrate and fungal communities' structure and sporulation rates discriminated upstream and downstream sites. Decomposition rates classified sites S4 and S2 as having a compromised ecosystem functioning. Although both functional and structural approaches gave the same results for the most impacted site (S4), they were complementary for moderately impacted sites (S2 and S3), and we therefore support the need for incorporating functional measures in evaluations of stream ecological integrity. - This study supports the need for incorporating functional measures in evaluations of stream ecological integrity.

  20. Bioaccumulation of polybrominated diphenyl ethers by the freshwater benthic amphipod Gammarus pulex. (United States)

    Tlili, Khawla; Labadie, Pierre; Bourges, Catherine; Desportes, Annie; Chevreuil, Marc


    This study reports on the relationship between polybrominated diphenyl ether (PBDE) levels in water, sediment, and the benthic macroinvertebrate Gammarus pulex, which plays a major ecological role in freshwater ecosystems. Samples were taken in a periurban watershed (near Paris, France), and PBDEs were systematically detected in sediment (≤727 ng g(-1) OC) and G. pulex (≤264 ng g(-1) lipids). PBDEs were also occasionally detected in the water column at low levels (∑ PBDEs < 1.5 ng L(-1)). The log values of bioaccumulation factors were in the range 7.8 ± 0.1-8.3 ± 0.4 L kg(-1) for tetra- and penta-BDEs, which were the only ones quantified in the dissolved phase of river water. Meanwhile, levels of individual tri- to hepta-PBDE congeners in G. pulex generally positively correlated with sediment levels, suggesting an equilibrium situation. Biota-to-sediment accumulation factors (BSAFs) of tri-hepta BDEs were congener specific and were in the range 0.5 ± 0.3-2.6 ± 1.2. For several PBDEs, BSAF values deviated from the expected range, likely because of in vivo metabolism.

  1. Trophic relations between macroinvertebrates in the Vlasina river (Serbia

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    Paunović M.


    Full Text Available The aim of the study presented was to define trophic relationships within the benthic community according to functional feeding groups (FFG in the Vlasina River (Southeast Serbia, with an attempt to use those results to describe the watercourse. In an investigation performed during 1996, a total of 125 macrozoobenthic taxa were identified, 95 of which were included in FFG analyses. Although the investigated part of the river, in its physical and chemical characteristics, as well as characteristics of the benthofauna, generally corresponds to what could be expected, certain variations of faunal composition were observed along the river. Two groups of sites were separated by FFG analysis - sites on the upper section of the river and on a tributary (the Gradska River comprised one group, while the remaining sites made up the other.

  2. The influence of oceanographic processes on pelagic-benthic coupling in polar regions: A benthic perspective (United States)

    Grebmeier, Jacqueline M.; Barry, James P.


    Benthic community abundance and biomass in polar marine systems is directly influenced by food supply from the overlying water column. Variability in hydrographic regimes, ice coverage, light, water column temperature and pelagic food web structure limit the amount of organic carbon reaching the benthos. Data from the high Arctic and Antarctic indicate that a large percentage of surface-produced organic matter is consumed by both macro- and micro-zooplankton as well as recycled in the water column via the microbial loop. This results in food-limited regimes for the underlying benthos. The few exceptions are nearshore continental shelf systems, such as in the Bering and Chukchi Seas in the western Arctic and portions of the Canadian Archipelago and Barents Sea in the eastern Arctic, where high benthic abundance and biomass occurs due to a tight coupling between water column primary production and benthic secondary production. A major difference between the Antarctic and Arctic is that the nearshore deep Ant