Toxic effects of isoproturon on periphyton communities a microcosm study

Science.gov (United States)

Schmitt-Jansen, Mechthild; Altenburger, Rolf

2005-02-01

Coastal and estuarine ecosystems are increasingly exposed to herbicide contamination. To study the potential risks of these pollutants, the establishment of periphyton communities under exposure of a concentration series of isoproturon in a range of 0.0024-0.312 mg L -1 was investigated in a microcosm study. After two weeks of growth, chronic effects on biomass development, measured as Chl a fluorescence, taxonomic composition and photosynthetic capacity of PS II of attached microalgae were analysed using a pulse-amplitude modulated (PAM) fluorescence-based method. Algal classes were differentiated according to their pigment systems using four excitation wavelengths. Biomass remained constant up to pre-exposure concentrations of 0.02 mg L -1 isoproturon but decreased within one order of magnitude at the highest test concentration. Algal classes shifted from diatoms to chlorophytes at pre-exposure concentrations of 0.02-0.39 mg L -1. Community structure of diatoms representing the dominant group of attached algae at lower test concentrations was studied by microscopic analysis revealing that species numbers were highest at lowest test concentrations as compared to controls. At higher test concentrations Navicula halophila dominated with 89% of the diatom biomass but was abnormally shaped. Pollution-induced community tolerance (PICT) of periphyton to isoproturon was determined by short-term inhibition tests of photosynthesis. Pre-exposed communities increased their effect concentrations (EC 50) up to threefold within the 0.039 mg L -1 pre-treatment. Our results suggest that attached microalgal communities have a high potential of tolerance development to isoproturon at lower levels of contamination due to the replacement of sensitive species by more tolerant algae, although these species seemed to be affected too. We conclude that herbicide concentrations in river basins, estuaries or coastal zones may change community structure and primary production of

Diffusive boundary layers and photosynthesis of the epilithic algal community of coral reefs

DEFF Research Database (Denmark)

Larkum, Anthony W.D.; Koch, Eva-Maria W.; Kühl, Michael

2003-01-01

The effects of mass transfer resistance due to the presence of a diffusive boundary layer on the photosynthesis of the epilithic algal community (EAC) of a coral reef were studied. Photosynthesis and respiration of the EAC of dead coral surfaces were investigated for samples from two locations......: the Gulf of Aqaba, Eilat (Israel), and One Tree Reef on the Great Barrier Reef (Australia). Microsensors were used to measure O2 and pH at the EAC surface and above. Oxygen profiles in the light and dark indicated a diffusive boundary layer (DBL) thickness of 180–590 µm under moderate flow (~0.08 m s-1...

Succession and seasonal variation in epilithic biofilms on artificial reefs in culture waters of the sea cucumber Apostichopus japonicus

Science.gov (United States)

Liu, Liming; Du, Rongbin; Zhang, Xiaoling; Dong, Shuanglin; Sun, Shichun

2017-01-01

Periphytic biofilms in aquaculture waters are thought to improve water quality, provide an additional food source, and improve the survival and growth of some reared animals. In the Asia- Pacific region, particularly in China, artificial reefs are commonly used in the commercial farming of sea cucumbers. However, few studies have examined the epilithic biofilms on the artificial reefs. To gain a better understanding of the succession of epilithic biofilms and their ecological processes in sea cucumber culture waters, two experiments were conducted in culture waters of the sea cucumber Apostichopus japonicus in Rongcheng, China, using artificial test panels. On the test panels of succession experiment, more than 67 species were identified in the biofilms. On the test panels of seasonal variation experiment, more than 46 species were recorded in the biofilms. In both experiments, communities of epilithic biofilms were dominated by diatoms, green algae and the annelid Spirorbis sp. In the initial colonization, the dominant diatoms were Cocconeis sp., Amphora spp. and Nitzschia closterium in June, which were succeeded by species of Navicula, Cocconeis and Nitzschia (July to September), and then by Licmophora abbreviata, Nitzschia closterium and Synedra spp. in the following months. A diatom bloom in the autumn and filamentous green algae burst in the summer were also observed. Ecological indices well annotated the succession and seasonal changes in epilithic communities. Multidimensional scaling (MDS) analysis found significant differences in diatom community composition among months and seasons. Fast growth of biofilms was observed in the summer and autumn, whereas the biomass of summer biofilms was largely made up of filamentous green algae. Present results show that the components of epilithic biofilms are mostly optimal foods of A. japonicus, suggesting that biofilms on artificial reefs may contribute important nutritional sources for sea cucumbers during their

State of the art on periphyton knowledge in Colombia

International Nuclear Information System (INIS)

Montoya Moreno, Yimmy; Aguirre R, Nestor

2013-01-01

Periphyton is a component of aquatic communities, composed by microbiota adhered to different substrates; plays a fundamental role in matter, energy and information transferences trough food webs and its study is important both from ecology, to understand ecosystems, as from environmental points of view, as periphyton is a good indicator of environmental processes and conditions, for instance water quality, in those ecosystems. Periphyton research is complex; even periphyton definition is still controversial. In addition to that, the variety of methodologies for comprehensive study, the diversity of peri phytic matrix architectures, the diversity of ecosystems and the absence of taxonomic schools in the country, are causing that few works are being published on the subject, which increases the value and importance of the work outlined in this review. The aim of this paper is to present the state of the art in research on periphyton in Colombia, analyzing different lines of research that has been developed and their progress. In order to do this, we examined 84 papers available to the authors. Most studies surveyed in this study (90%) correspond to the study of phycoperiphyton; the remaining 10% included both components of periphyton; one paper was dedicated exclusively to zooperiphyton. Only 10.5% of investigations (8 papers) have been dedicated to detailed taxonomic study; other publications study the structure and dynamics of the periphytic community.

Preliminary evaluation of an in vivo fluorometer to quantify algal periphyton biomass and community composition

Science.gov (United States)

Harris, Theodore D.; Graham, Jennifer L.

2015-01-01

The bbe-Moldaenke BenthoTorch (BT) is an in vivo fluorometer designed to quantify algal biomass and community composition in benthic environments. The BT quantifies total algal biomass via chlorophyll a (Chl-a) concentration and may differentiate among cyanobacteria, green algae, and diatoms based on pigment fluorescence. To evaluate how BT measurements of periphytic algal biomass (as Chl-a) compared with an ethanol extraction laboratory analysis, we collected BT- and laboratory-measured Chl-a data from 6 stream sites in the Indian Creek basin, Johnson County, Kansas, during August and September 2012. BT-measured Chl-a concentrations were positively related to laboratory-measured concentrations (R2 = 0.47); sites with abundant filamentous algae had weaker relations (R2 = 0.27). Additionally, on a single sample date, we used the BT to determine periphyton biomass and community composition upstream and downstream from 2 wastewater treatment facilities (WWTF) that discharge into Indian Creek. We found that algal biomass increased immediately downstream from the WWTF discharge then slowly decreased as distance from the WWTF increased. Changes in periphyton community structure also occurred; however, there were discrepancies between BT- and laboratory-measured community composition data. Most notably, cyanobacteria were present at all sites based on BT measurements but were present at only one site based on laboratory-analyzed samples. Overall, we found that the BT compared reasonably well with laboratory methods for relative patterns in Chl-a but not as well with absolute Chl-aconcentrations. Future studies need to test the BT over a wider range of Chl-aconcentrations, in colored waters, and across various periphyton assemblages.

Epilithic lichens in rock communities on the territory of the Botanical Garden of PetrSU

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Serapionova Olesya

2017-12-01

Full Text Available Species diversity of epilithic lichens (54 species on the territory of the Botanical Garden of Petrozavodsk State University with different character of anthropogenic impact has been reported. Nine species of epilithic lichens are recorded as new for the studied territory and species Acarospora nitrophila, Lecanora sulphurea, Lecidea lithophila - as new for the biogeographical province of Karelia onegensis. The highest number of lichen species was found within area of observation deck “Devil's chair” where the greatest variety of microhabitats was presented.

Succession of Periphyton and Phytoplankton Assemblages in Years with Varying Amounts of Precipitation in a Shallow Urban Lake (Lake Jeziorak Mały, Poland

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Zębek Elžbieta

2014-08-01

Full Text Available This study of periphyton assemblages (periphyton in separator pipes, epilithon and epiphyton and phytoplankton was carried out in Lake Jeziorak Maly in 1997-2003 and 2005. Since precipitation amounts varied in these years, changes in the abundance, biomass, taxonomic group structure, spe-cies diversity and dominant taxa of these assemblages were analyzed in relation to the physical and chemical water parameters. The periphyton in pipes had their highest abundance and biomass at the mean precipitation in the vegetative season and at maximum precipitations in winter 2000, and also in the 1997 vegetative season when there were high levels of electrolytic conductivity and orthophosphate and chloride concentrations. The assemblage was dominated by the diatoms Diatoma vulgaris which was resistant to washing and Navicula gregaria resistant to high amounts of organic matter. Similarly, maximum abundance and biomass of epilithon was found at the maximum precipitation level. However, in 2003 there was a low precipitation level which favoured habitation by epilithic filamentous chlorophytes, especially Ulothrix tenuissima. Meanwhile, epiphyton and phytoplankton thrived best in the high precipitation conditions and moderate chloride concentration in 2001. These assemblages were dominated by species typical for eutrophic waters, such as Gomphonema oliva-ceum and Planktolyngbya brevicellularis. Differences in the dynamics of periphyton assemblages and phytoplankton in the studied years indicate varying succession rates in these assemblages, especially in the separator pipes and on stones. These phenomena are considered to be related to the different environmental conditions engendered by variable amounts of precipitation.

Periphyton indicate effects of wastewater discharge in the near-coastal zone, Perth (Western Australia)

Science.gov (United States)

Cosgrove, Jeffrey; Walker, Di; Morrison, Peter; Hillman, Karen

2004-10-01

Periphyton communities on artificial substrata were successfully utilised as a biological indicator of the potential eutrophic effects of wastewater discharge into coastal waters off Perth, Western Australia. Biomass and percentage carbonate content measurements of periphyton communities grown in situ indicated that the periphyton primary production (organic weight) was enhanced in the vicinity of the discharge outlets, with a significant negative correlation between distance north of the northern outlet in Whitfords Lagoon and periphyton organic weight (OW) observed in autumn at a depth of 4 m ( r = -0.704, P relatively calm autumn season and substrata at depths of 2 m and 4 m. Thus, in favourable conditions phytoplankton and high relief reef communities are more likely to exhibit a eutrophic influence (in the form of enhanced primary production) of the treated wastewater discharge. Laboratory studies confirmed that treated wastewater, diluted 100-fold to estimate surface concentrations above the wastewater outfalls in the field, stimulates periphyton growth above levels recorded in unpolluted seawater ( F = 12.485; P = 0.0073).

Distribution of Epilithic Diatoms in Estuaries of the Korean Peninsula in Relation to Environmental Variables

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Ha-Kyung Kim

2015-11-01

Full Text Available This study explores the relationships between environmental factors and the distribution of epilithic diatoms in 161 estuaries of three coastal areas on the Korean peninsula. We investigated epilithic diatoms, water quality, and land use in the vicinities of the estuaries during the months of May 2012, 2013 and 2014, because Korea is relatively free from the influences of rainfall at that time of year. We recorded 327 diatom taxa from the study sites, and the assemblage was dominated by members of the Naviculaceae. Bacillariaceae accounted for the largest proportion of diatoms, and Nitzschia inconspicua (18% and N. frustulum (9.6% were the most dominant species. A cluster analysis based on epilithic diatom abundance suggested that the epilithic diatom communities of Korean estuaries can be classified into four large groups (G according to geography, as follows: Ia—the East Sea watershed, Ib—the eastern watershed of the South Sea, IIa—the West Sea watershed, and IIb—the western watershed of the South Sea. The former two groups, Ia and Ib, showed higher proportions of forest land cover and use, higher species occurrence, lower salinity, lower turbidity, and lower concentrations of nutrients than the latter two groups, while the latter groups, IIa and IIb, had higher proportions of agricultural land cover and use, higher electrical conductivity, higher turbidity, higher concentrations of nutrients, and lower species occurrence. The environmental factors underlying the distribution of epilithic diatoms, representative of each region, are as follows: dissolved oxygen and forest land cover and use for Reimeria sinuate and Rhoicosphenia abbreviate of the East Sea (ES, salinity and turbidity for Tabularia fasciculate of the West Sea (WS, and biochemical oxygen demand (BOD and nutrients for Cyclotella meneghiniana of the WS. On the other hand, the most influential environmental factors affecting the occurrence of indicator species showing the

Review on Periphyton as Mediator of Nutrient Transfer in Aquatic Ecosystems

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Surjya K. Saikia

2011-12-01

Full Text Available In the studies of aquatic ecology, periphyton has been uncared for despite its vital role in nutrient uptake and transfer to the upper trophic organisms. Being the component of food chain as attached organism it takes part in nutrient cycling in the ecosystem like that of suspended planktonic counterparts. The present review, with an aim to understand the role of periphyton in nutrient transfer from benthic environment to upper trophic level, focuses many aspects of periphyton-nutrient relationship based on available literatures. It also attempts to redefine periphyton, as a part of biofilm, harboring nutrient components like protein, fat and carbohydrate preferably in its extracellular polymeric substance (EPS, cyanobacteria, diatom and other algal communities. In addition to physical processes, nutrient uptake by periphyton is catalyzed by enzymes like Nitrogen Reductase and Alkaline Phosphatase from the environment. This uptake and transfer is further regulated by periphytic C: nutrient (N or P stoichiometry, colonization time, distribution of periphyton cover on sediments and macrophytes, macronutrient concentration, grazing, sloughing, temperature, and advective transport. The Carbon (C sources of periphyton are mainly dissolve organic matter and photosynthetic C that enters into higher trophic levels through predation and transfers as C-rich nutrient components. Despite of emerging interests on utilizing periphyton as nutrient transfer tool in aquatic ecosystem, the major challenges ahead for modern aquatic biologists lies on determining nutrient uptake and transfer rate of periphyton, periphytic growth and simulating nutrient models of periphyton to figure a complete energy cycle in aquatic ecosystem.

Response of periphyton fatty acid composition to supplemental flows in the upper Esopus Creek, Catskill Mountains, New York

Science.gov (United States)

George, Scott D.; Ernst, Anne G.; Baldigo, Barry P.; Honeyfield, Dale C.

2016-01-07

Fatty acid analysis of periphyton is an emerging tool for assessing the condition of a stream ecosystem on the basis of its water quality. The study presented in this report was designed to test the hypothesis that periphyton communities have a fatty acid profile that can detect excessive turbidity and suspended sediment. The fatty acid composition of periphyton was assessed during two seasons upstream and downstream from an underground aqueduct that provides supplemental flows, which are a potential source of turbidity and suspended sediment on the upper Esopus Creek, New York. These data were compared with measurements of periphyton standing crop, diatom community structure and integrity, and basic water-quality parameters. Periphyton standing crop and diatom community integrity indicated little evidence of impairment from the supplemental flows. The relative abundances of two physiologically important fatty acids, γ-linolenic acid (18:3ω6) and eicosapentaenoic acid (20:5ω3), were significantly lower downstream from the supplemental flows and multivariate analyses of fatty acid profiles identified significant differences between sites upstream and downstream from the supplemental flows. Individual fatty acids and summary metrics, however, were not significantly correlated with turbidity or suspended sediment. Together, these results indicate that the supplemental flows may cause some measurable effects but they do not constitute a major disturbance to the periphyton community on the upper Esopus Creek. Fatty acid analysis may have potential as a tool for monitoring changes in periphyton nutritional composition that may reflect water quality and ecosystem health but needs to be further evaluated around a more definitive source of water-quality impairment.

Factors Controlling Changes in Epilithic Algal Biomass in the Mountain Streams of Subtropical Taiwan.

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Yi-Ming Kuo

Full Text Available In upstream reaches, epilithic algae are one of the major primary producers and their biomass may alter the energy flow of food webs in stream ecosystems. However, the overgrowth of epilithic algae may deteriorate water quality. In this study, the effects of environmental variables on epilithic algal biomass were examined at 5 monitoring sites in mountain streams of the Wuling basin of subtropical Taiwan over a 5-year period (2006-2011 by using a generalized additive model (GAM. Epilithic algal biomass and some variables observed at pristine sites obviously differed from those at the channelized stream with intensive agricultural activity. The results of the optimal GAM showed that water temperature, turbidity, current velocity, dissolved oxygen (DO, pH, and ammonium-N (NH4-N were the main factors explaining seasonal variations of epilithic algal biomass in the streams. The change points of smoothing curves for velocity, DO, NH4-N, pH, turbidity, and water temperature were approximately 0.40 m s-1, 8.0 mg L-1, 0.01 mg L-1, 8.5, 0.60 NTU, and 15°C, respectively. When aforementioned variables were greater than relevant change points, epilithic algal biomass was increased with pH and water temperature, and decreased with water velocity, DO, turbidity, and NH4-N. These change points may serve as a framework for managing the growth of epilithic algae. Understanding the relationship between environmental variables and epilithic algal biomass can provide a useful approach for maintaining the functioning in stream ecosystems.

The potential of fish production based on periphyton

NARCIS (Netherlands)

Dam, van A.A.; Beveridge, M.C.M.; Azim, M.E.; Verdegem, M.C.J.

2002-01-01

Periphyton is composed of attached plant and animal organisms embedded in a mucopolysaccharide matrix. This review summarizes research on periphyton-based fish production and on periphyton productivity and ingestion by fish, and explores the potential of developing periphyton-based aquaculture.

Oxygen dynamics in periphyton communities and associated effects on phosphorus release from lake sediments

International Nuclear Information System (INIS)

Carlton, R.G.

1986-01-01

Periphyton is typically a heterogeneous assemblage of filamentous and single celled photoautotrophic and heterotrophic micoorganisms suspended in a mucopolysaccharide matrix which they produce. By definition, the assemblage is attached to a substratum such as rock, sediment, or plant in an aquatic environment. Microtechniques with high spatial and temporal resolution are required to define metabolic interactions among the heterotrophic and autotrophic constituents, and between periphyton and its environment. This study used oxygen sensitive microelectrodes with tip diameters of 32 P radiotracer and that permitted manipulation of the velocity, flushing rate, and oxygen concentration of overlying water was developed to investigate the role of photosynthetic oxygen production on the phosphorus dynamics in lake sediments colonized by epipelic periphyton. 89 refs., 20 figs

Short-Term Effects of Drying-Rewetting and Long-Term Effects of Nutrient Loading on Periphyton N:P Stoichiometry

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Andres D. Sola

2018-01-01

Full Text Available Nitrogen (N and phosphorus (P concentrations and N:P ratios critically influence periphyton productivity and nutrient cycling in aquatic ecosystems. In coastal wetlands, variations in hydrology and water source (fresh or marine influence nutrient availability, but short-term effects of drying and rewetting and long-term effects of nutrient exposure on periphyton nutrient retention are uncertain. An outdoor microcosm experiment simulated short-term exposure to variation in drying-rewetting frequency on periphyton mat nutrient retention. A 13-year dataset from freshwater marshes of the Florida Everglades was examined for the effect of long-term proximity to different N and P sources on mat-forming periphyton nutrient standing stocks and stoichiometry. Field sites were selected from one drainage with shorter hydroperiod and higher connectivity to freshwater anthropogenic nutrient supplies (Taylor Slough/Panhandle, TS/Ph and another drainage with longer hydroperiod and higher connectivity to marine nutrient supplies (Shark River Slough, SRS. Total P, but not total N, increased in periphyton mats exposed to both low and high drying-rewetting frequency with respect to the control mats in our experimental microcosm. In SRS, N:P ratios slightly decreased downstream due to marine nutrient supplies, while TS/Ph increased. Mats exposed to short-term drying-rewetting had higher nutrient retention, similar to nutrient standing stocks from long-term field data. Periphyton mat microbial communities may undergo community shifts upon drying-rewetting and chronic exposure to nutrient loads. Additional work on microbial species composition may further explain how periphyton communities interact with drying-rewetting dynamics to influence nutrient cycling and retention in wetlands.

Hydrophysical conditions and periphyton in natural rivers. Analysis and predictive modelling of periphyton by changed regulations

International Nuclear Information System (INIS)

Stokseth, S.

1994-10-01

The objective of this thesis has been to examine the interaction between hydrodynamical and physical factors and the temporal and spatial dynamics of periphyton in natural steep rivers. The study strategy has been to work with quantitative system variables to be able to evaluate the potential usability of a predictive model for periphyton changes as a response to river regulations. The thesis is constituted by a theoretical and an empirical study. The theoretical study is aimed at presenting a conceptual model of the relevant factors based on an analysis of published studies. Effort has been made to evaluate and present the background material in a structured way. To concurrently handle the spatial and temporal dynamics of periphyton a new method for data collection has been developed. A procedure for quantifying the photo registrations has been developed. The simple hydrodynamical parameters were estimated from a set of standard formulas whereas the complex parameters were estimated from a three dimensional simulation model called SSIIM. The main conclusion from the analysis is that flood events are the major controlling factors wrt. periphyton biomass and that water temperature is of major importance for the periphyton resistance. Low temperature clearly increases the periphyton erosion resistance. Thus, to model or control the temporal dynamics the river periphyton, the water temperature and the frequency and size of floods should be regarded the most significant controlling factors. The data in this study has been collected from a river with a stable water quality and frequent floods. 109 refs., 41 figs., 34 tabs

Temperature modulates phototrophic periphyton response to chronic copper exposure

International Nuclear Information System (INIS)

Lambert, Anne Sophie; Dabrin, Aymeric; Morin, Soizic; Gahou, Josiane; Foulquier, Arnaud; Coquery, Marina; Pesce, Stéphane

2016-01-01

Streams located in vineyard areas are highly prone to metal pollution. In a context of global change, aquatic systems are generally subjected to multi-stress conditions due to multiple chemical and/or physical pressures. Among various environmental factors that modulate the ecological effects of toxicants, special attention should be paid to climate change, which is driving an increase in extreme climate events such as sharp temperature rises. In lotic ecosystems, periphyton ensures key ecological functions such as primary production and nutrient cycling. However, although the effects of metals on microbial communities are relatively well known, there is scant data on possible interactions between temperature increase and metal pollution. Here we led a study to evaluate the influence of temperature on the response of phototrophic periphyton to copper (Cu) exposure. Winter communities, collected in a 8 °C river water, were subjected for six weeks to four thermal conditions in microcosms in presence or not of Cu (nominal concentration of 15 μg L"−"1). At the initial river temperature (8 °C), our results confirmed the chronic impact of Cu on periphyton, both in terms of structure (biomass, distribution of algal groups, diatomic composition) and function (photosynthetic efficiency). At higher temperatures (13, 18 and 23 °C), Cu effects were modulated. Indeed, temperature increase reduced Cu effects on algal biomass, algal class proportions, diatom assemblage composition and photosynthetic efficiency. This reduction of Cu effects on periphyton may be related to lower bioaccumulation of Cu and/or to selection of more Cu-tolerant species at higher temperatures. - Highlights: • At in situ temperature, Cu impacted structure and activity of phototrophic biofilms. • Cu effects were reduced with increasing temperature (from +5 °C to +15 °C). • The decrease in Cu effects may be related to lower Cu bioaccumulation in biofilms. • Changes in diatom

Trophic partitioning among three littoral microcrustaceans: relative importance of periphyton as food resource

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Alexandre Bec

2012-07-01

Full Text Available The high species richness of zooplankton communities in macrophytes littoral zones could result from the diversity of potential trophic niches found in such environment. In macrophytes littoral zones, in addition to phytoplankton, neustonic, benthic and epiphytic biofilms can also be potential components of the microcrustacean diet. Here, we investigated the ability of three large cladocerans: Daphnia longispina, Simocephalus vetulus and Eurycercus lamellatus, to develop on periphyton as their only food source or as a complement to a phytoplankton resource in scarce supply. D. longispina exhibited a very low growth and reproduction rates on the periphytic resource and as S. vetulus seems unable to scrape on periphyton. In contrast, E. lamellatus could not grow on phytoplankton, and appears to be an obligatory periphyton scraper. This latter finding contrasts with previous studies suggesting that E. lamellatus could be able to scrap periphyton as well as filter-feed on suspended matter. These differences in feeding strategy probably reflect the different trophic niches occupied by these three species in macrophytes littoral zones, and may explain at least in part their ability to coexist in the same environment.

Short-term uptake of heavy metals by periphyton algae

Energy Technology Data Exchange (ETDEWEB)

Vymazal, J.

1984-12-31

The utilization of periphyton for the removal of heavy metals from enriched small streams has been examined. By means of short-term batch laboratory experiments the courses of metal uptake have been studied. For uptake study naturally growing periphyton community and periphytic filamentous algae Cladophora glomerata and Oedogonium rivulare have been used. Uptakes of nine heavy metals (Pb, Cd, Cu, Co, Cr, Ni, Zn, Fe and Mn) have been determined during four hours exposure. In addition the influence of humic substances on heavy metals uptake has been determined. Uptake of all metals increased during four hours exposure but not in the same way. Some metals were removed continuously (Ni, Cr, Fe and Mn), other metals were removed more rapidly during the first hour or first two hours of exposure and then only slight removal continued (Cu, Pb, Cd, Co). Uptake of Zn was rather unambiguous. Results of these experiments suggest that the course of uptake for individual metals could be similar for most periphyton algae. It was established that humic substances significantly reduce heavy metals uptake. The highest decrease of uptake was observed in Cu, Cr, Co and Cd. The results of model experiments are being tested in a pilot scale with respect to the demands of engineering practice. (J.R.)

Diversity and biomineralization potential of the epilithic bacterial communities inhabiting the oldest public stone monument of Cluj-Napoca (Transylvania, Romania)

Czech Academy of Sciences Publication Activity Database

Andrei, Adrian-Stefan; Pausan, M.R.; Tamas, T.; Har, N.; Barbu-Tudoran, L.; Leopold, N.; Banciu, H.L.

2017-01-01

Roč. 8, March (2017), č. článku 372. ISSN 1664-302X Institutional support: RVO:60077344 Keywords : limestone statue * epilithic microbiota * bacteria l cultivation * carbonatogenesis * vaterite Subject RIV: EE - Microbiology, Virology OBOR OECD: Microbiology Impact factor: 4.076, year: 2016

Effect of glyphosate acid on biochemical markers of periphyton exposed in outdoor mesocosms in the presence and absence of the mussel Limnoperna fortunei.

Science.gov (United States)

Iummato, María Mercedes; Pizarro, Haydée; Cataldo, Daniel; Di Fiori, Eugenia; Dos Santos Afonso, María; Del Carmen Ríos de Molina, María; Juárez, Ángela Beatriz

2017-07-01

Glyphosate is currently the most widely used herbicide in agricultural production. It generally enters aquatic ecosystems through surface water runoff and aerial drift. We evaluated the effect of glyphosate acid on biochemical parameters of periphyton exposed to concentrations of 1, 3, and 6 mg/L in outdoor mesocosms in the presence and absence of the mussel Limnoperna fortunei. Periphyton ash-free dry weight, chlorophyll a content, carotene/chlorophyll a ratio, lipid peroxidation levels, and superoxide dismutase and catalase activities were determined at days 0, 1, 7, 14, and 26 of the experimental period. Ash-free dry weight was similar between control and glyphosate-treated periphyton in the absence of L. fortunei. The latter had significantly lower carotene to chlorophyll a ratios and enzyme activities, and higher lipid peroxidation levels and chlorophyll a content than the former. These results show an adverse effect of glyphosate on the metabolism of periphyton community organisms, possibly inducing oxidative stress. On the contrary, no differences were observed in any of these variables between control and glyphosate-treated periphyton in the presence of L. fortunei. Mussels probably attenuated the herbicide effects by contributing to glyphosate dissipation. The results also demonstrate that biochemical markers provide useful information that may warn of herbicide impact on periphyton communities. Environ Toxicol Chem 2017;36:1775-1784. © 2016 SETAC. © 2017 SETAC.

The response of stream periphyton to Pacific salmon: using a model to understand the role of environmental context

Science.gov (United States)

Bellmore, J. Ryan; Fremier, Alexander K.; Mejia, Francine; Newsom, Michael

2014-01-01

1. In stream ecosystems, Pacific salmon deliver subsidies of marine-derived nutrients and disturb the stream bed during spawning. The net effect of this nutrient subsidy and physical disturbance on biological communities can be hard to predict and is likely to be mediated by environmental conditions. For periphyton, empirical studies have revealed that the magnitude and direction of the response to salmon varies from one location to the next. Salmon appear to increase periphyton biomass and/or production in some contexts (a positive response), but decrease them in others (a negative response). 2. To reconcile these seemingly conflicting results, we constructed a system dynamics model that links periphyton biomass and production to salmon spawning. We used this model to explore how environmental conditions influence the periphyton response to salmon. 3. Our simulations suggest that the periphyton response to salmon is strongly mediated by both background nutrient concentrations and the proportion of the stream bed suitable for spawning. Positive periphyton responses occurred when both background nutrient concentrations were low (nutrient limiting conditions) and when little of the stream bed was suitable for spawning (because the substratum is too coarse). In contrast, negative responses occurred when nutrient concentrations were higher or a larger proportion of the bed was suitable for spawning. 4. Although periphyton biomass generally remained above or below background conditions for several months following spawning, periphyton production returned quickly to background values shortly afterwards. As a result, based upon our simulations, salmon did not greatly increase or decrease overall annual periphyton production. This suggests that any increase in production by fish or invertebrates in response to returning salmon is more likely to occur via direct consumption of salmon carcasses and/or eggs, rather than the indirect effects of greater periphyton production. 5

Diversity and structure of periphyton and metaphyton diatom communities in a tropical wetland in Mexico Diversidad y estructura de las comunidades de diatomeas del perifiton y el metafiton en un humedal tropical en México

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Claudia Ibarra

2009-12-01

Full Text Available We investigated the structure and diversity of diatoms in communities of metaphyton and periphyton from the wetland of El Edén Ecological Reserve, Quintana Roo, Mexico. In spite of the close association and communication between these communities, our comparisons reveal that the 2 communities have distinct species assemblages, with the periphyton being more diverse overall. We fit abundance curves for periphyton and metaphyton, and argue that our results are consistent with communities where environmental conditions play a more important role than competition in structuring diatom species assemblages.Investigamos la estructura y la diversidad de las comunidades de diatomeas en el metafiton y el perifiton del humedal de la Reserva Ecológica El Edén, Quintana Roo, México. A pesar de la cercana asociación entre estas comunidades, nuestro análisis revela que tanto el perifiton como el metafiton consisten de distintas asociaciones de especies y el perifiton es el más diverso. Las distribuciones de las abundancias de las especies de diatomeas satisfacen curvas de distribución log-normal; esto significa que en las comunidades estudiadas, las condiciones ambientales juegan un papel más importante que la competencia para determinar su estructura.

Physical, Chemical and Periphyton/Phytoplankton Study of Onah ...

African Journals Online (AJOL)

physico-chemical parameter, viz: ionic conductivity factor contributed 26.07%, nutrient factor contributed 40.61% while dissolved oxygen factor contributed 33.32%. Three divisions, eight families and ten species of periphyton were encountered. The most abundant periphyton species recorded are Closterium spp. (26.37%) ...

Soil and periphyton indicators of anthropogenic water-quality changes in a rainfall-driven wetland

Science.gov (United States)

McCormick, P.V.

2011-01-01

Surface soils and periphyton communities were sampled across an oligotrophic, soft-water wetland to document changes associated with pulsed inputs of nutrient- and mineral-rich canal drainage waters. A gradient of canal-water influence was indicated by the surface-water specific conductance, which ranged between 743 and 963 ??S cm-1 in the canals to as low as 60 ??S cm-1 in the rainfall-driven wetland interior. Changes in soil chemistry and periphyton taxonomic composition across this gradient were described using piecewise regressions models. The greatest increase in soil phosphorus (P) concentration occurred at sites closest to the canal while soil mineral (sulfur, calcium) concentrations increased most rapidly at the lower end of the gradient. Multiple periphyton shifts occurred at the lower end of the gradient and included; (1) a decline in desmids and non-desmid filamentous chlorophytes, and their replacement by a diatom-dominated community; (2) the loss of soft-water diatom indicator species and their replacement by hard-water species. Increased dominance by cyanobacteria and eutrophic diatom indicators occurred closer to the canals. Soil and periphyton changes indicated four zones of increasing canal influence across the wetland: (1) a zone of increasing mineral concentrations where soft-water taxa remained dominant; (2) a transition towards hard-water, oligotrophic diatoms as mineral concentrations increased further; (3) a zone of dominance by these hard-water species; (4) a zone of rapidly increasing P concentrations and dominance by eutrophic taxa. In contrast to conclusions drawn from routine water-chemistry monitoring, measures of chemical and biological change presented here indicate that most of this rainfall-driven peatland receives some influence from canal discharges. These changes are multifaceted and induced by shifts in multiple chemical constituents. ?? 2010 US Government.

Rapid sewage pollution assessment by means of the coverage of epilithic taxa in a coastal area in the SW Atlantic.

Science.gov (United States)

Becherucci, M E; Jaubet, M L; Saracho Bottero, M A; Llanos, E N; Elías, R; Garaffo, G V

2018-07-01

The sewage pollution impact over coastal environment represents one of the main reasons explaining the deterioration of marine coastal ecosystems around the globe. This paper aims to detect promptly a putative sewage pollution impact in a Southwestern Atlantic coastal area of Argentina as well as to identify a straightforward way for monitoring, based on the relative abundance coverage of the intertidal epilithic taxa. Four sampling sites were distributed at increased distances from the sewage outfall where the cover of individual epilithic species was visually estimated. The surrounded outfall area (i.e. outfall site) resulted polluted with high percentages of organic matter in sediment and Enterococcus concentration in seawater. The structure of the community showed a remarkable difference between the polluted site (outfall site) and the unpolluted sites. The polychaete Boccardia proboscidea dominated the outfall site with variable abundances of the green algae Ulva sp. during the period of study, decreasing the diversity of the community, while the mussel Brachidontes rodriguezii and variable abundances of several algae species dominated the unpolluted sites. The monitoring of the benthic community represents an effective, non-destructive, relative inexpensive and rapid method to assess the health of the coastal environment in the study area. The large abundance of B. proboscidea along with the absence of B. rodriguezii individuals at coastal ecosystem with certain gradient of pollution. Copyright © 2018 Elsevier B.V. All rights reserved.

Co-contamination of Cu and Cd in paddy fields: Using periphyton to entrap heavy metals

Energy Technology Data Exchange (ETDEWEB)

Yang, Jiali [State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Sciences, Chinese Academy of Sciences, 71 East Beijing Road, Nanjing 210008 (China); College of Resource and Environment, University of Chinese Academy of Sciences, Beijing 100049 (China); Tang, Cilai [Department of Environmental Engineering, College of Hydraulic & Environmental Engineering, China Three Gorges University, Yichang 443002 (China); Wang, Fengwu [State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Sciences, Chinese Academy of Sciences, 71 East Beijing Road, Nanjing 210008 (China); School of Civil Engineering, East China Jiaotong University, 808 Shuang Gang East Road, Nanchang, Jiangxi 330013 (China); Wu, Yonghong, E-mail: yhwu@issas.ac.cn [State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Sciences, Chinese Academy of Sciences, 71 East Beijing Road, Nanjing 210008 (China)

2016-03-05

Highlights: • Periphyton was capable of simultaneously entrapping Cu and Cd from paddy fields. • Cu and Cd bioavailability decreased with time after exposure to periphyton. • Periodic adsorption–desorption was the main mechanism used to remove Cd and Cu. • Periphyton was able to adapt to steady accumulation of Cu and Cd. • The inclusion of periphyton will help entrap heavy metals in paddy fields. - Abstract: The ubiquitous native periphyton was used to entrap Cu and Cd from paddy fields. Results showed that Cu- and Cd-hydrate species such as CuOH{sup +}, Cu{sub 2}(OH){sub 2}{sup 2+}, CdOH{sup +}, and Cu{sub 3}(OH){sub 4}{sup 2+} decreased with time in the presence of periphyton. When the initial concentrations of Cu and Cd were 10 mg/L, the heavy metal content in the periphyton fluctuated from 145.20 mg/kg to 342.42 mg/kg for Cu and from 101.75 mg/kg to 236.29 mg/kg for Cd after 2 h exposure. The concentration of Cd in periphytic cells varied from 42.93 mg/kg to 174 mg/kg after 2 h. The dominant periphyton microorganism species shifted from photoautotrophs to heterotrophs during the exposure of periphyton to Cu and Cd co-contamination. Although Cu and Cd could inhibit periphyton photosynthesis and carbon utilization, the periphyton was able to adapt to the test conditions. Cu and Cd accumulation in rice markedly decreased in the presence of periphyton while the number of rice seeds germinating was higher in the periphyton treatments. These results suggest that the inclusion of native periphyton in paddy fields provides a promising buffer to minimize the effects of Cu and Cd pollution on rice growth and food safety.

Relation of periphyton and benthic invertebrate communities to environmental factors and land use at selected sites in part of the upper Mississippi River basin, 1996-98

Science.gov (United States)

ZumBerge, Jeremy Ryan; Lee, Kathy E.; Goldstein, Robert M.

2003-01-01

The Upper Mississippi River Basin is one of the hydrologic systems selected for study by the National Water-Quality Assessment (NAWQA) Program of the U.S. Geological Survey. NAWQA utilizes a multi-disciplinary approach to explain factors that affect water quality. Part of the NAWQA design addresses the relation of land use and environmental factors to periphyton and benthic invertebrate communities in streams.

Nutrient capture and recycling by periphyton attached to modified agrowaste carriers.

Science.gov (United States)

Wan, Juanjuan; Liu, Xuemei; Wu, Chenxi; Wu, Yonghong

2016-04-01

The reuse of periphytic biofilm from traditional wastewater treatment (i.e., active sludge process) is inefficient to recycle nutrients due to low accumulation of nutrients. Then, in this study, peanut shell (PS), rice husk (RH), decomposed peanut shell (DPS), acidified rice husks (ARH), and a commonly used carrier-ceramsite (C, as the control)-were used to support the growth of periphyton. Results showed that DPS and ARH supported significantly higher periphyton biomass and metabolic versatility than PS and RH, respectively, due to the increased presence of positive groups. The total nitrogen (TN) and total phosphorus (TP) captured by periphyton were enhanced by 600-657 and 833-3255 % for DPS, and 461-1808 and 21-308 % for ARH, respectively. The removal of nutrients from simulated eutrophic surface waters using periphyton attached to DPS was improved by 24-47 % for TP, 12-048 % for TN, and 15-78 % for nitrate compared to the control. The results indicate that the periphyton attached to modified agrowaste was capable of efficiently entrapping and storing N and P from eutrophic water. This study also implies that the mixture of periphyton and the modified agrowaste carriers are promising raw materials of biofertilizer.

Stream periphyton responses to mesocosm treatments of ...

Science.gov (United States)

A stream mesocosm experiment was designed to compare biotic responses among streams exposed to an equal excess specific conductivity target of 850 µS/cm relative to a control that was set for 200 µS/cm and three treatments comprised of different major ion contents. Each treatment and the control was replicated 4 times at the mesocosm scale (16 mesocosms total). The treatments were based on dosing the background mesocosm water, a continuous flow-through mixture of natural river water and reverse osmosis treated water, with stock salt solutions prepared from 1) a mixture of sodium chloride and calcium chloride (Na/Cl chloride), 2) sodium bicarbonate, and 3) magnesium sulfate. The realized average specific conductance over the first 28d of continuous dosing was 827, 829, and 847 µS/cm, for the chloride, bicarbonate, and sulfate based treatments, respectively, and did not differ significantly. The controls averaged 183 µS/cm. Here we focus on comparing stream periphyton communities across treatments based on measurements obtained from a Pulse-Amplitude Modulated (PAM) fluorometer. The fluorometer is used in situ and with built in algorithms distributes the total aerial algal biomass (µg/cm2) of the periphyton among cyanobacteria, diatoms, and green algae. A measurement is recorded in a matter of seconds and, therefore, many different locations can be measured with in each mesocosm at a high return frequency. Eight locations within each of the 1 m2 (0.3 m W x 3

Mercury methylation and demethylation by periphyton biofilms and their host in a fluvial wetland of the St. Lawrence River (QC, Canada)

International Nuclear Information System (INIS)

Hamelin, Stéphanie; Planas, Dolors; Amyot, Marc

2015-01-01

Wetlands in large rivers are important sites of production of the neurotoxin methylmercury (MeHg), and the periphyton growing on wetland macrophytes are increasingly recognized as key players in this production and transfer in food webs. Information is lacking about mercury methylation (K m ) and demethylation (K d ) rates in periphytic biofilms from the Northern Hemisphere, as well as about the drivers of net MeHg production, hampering ecosystem modeling of Hg cycling. Mercury methylation and demethylation rates were measured in periphytic biofilms growing on submerged plants in a shallow fluvial lake located in a temperate cold region (St. Lawrence River, Quebec, Canada). Incubations were performed in situ within macrophyte beds using low-level spikes of 199 HgO and Me 200 Hg stable isotopes as tracers. A direct relationship was observed between K m (0.002 to 0.137 d −1 ) and [MeHg] in periphyton. A similar relationship was found between K d (0.096 to 0.334 d −1 ) and [inorganic Hg]. Periphyton of Lake St. Pierre reached high levels of net MeHg production that were two orders of magnitude higher than those found in local sediment. This production varied through the plant growing season and was mainly driven by environmental variables such as depth of growth, available light, dissolved oxygen, temperature, plant community structure, and productivity of the habitat. - Highlights: • Periphyton Hg methylation and demethylation were studied in a large fluvial lake. • Addition of stable Hg isotopes was used to obtain in situ rates for these processes. • Net methylation was higher in periphyton than in local sediments. • Methylation and demethylation rates fluctuated during the summer. • Key drivers of rates were depth, light, temperature, and community structure

Mercury methylation and demethylation by periphyton biofilms and their host in a fluvial wetland of the St. Lawrence River (QC, Canada)

Energy Technology Data Exchange (ETDEWEB)

Hamelin, Stéphanie; Planas, Dolors [GRIL, Département de sciences biologiques, Université du Québec à Montréal, C.P. 8888, Succursale Centre-Ville, Montreal, Quebec H3C 3P8 (Canada); Amyot, Marc [GRIL, Département de sciences biologiques, Université de Montréal, C.P. 6128, Succursale Centre-Ville, Montréal, Quebec H3C 3J7 (Canada)

2015-04-15

Wetlands in large rivers are important sites of production of the neurotoxin methylmercury (MeHg), and the periphyton growing on wetland macrophytes are increasingly recognized as key players in this production and transfer in food webs. Information is lacking about mercury methylation (K{sub m}) and demethylation (K{sub d}) rates in periphytic biofilms from the Northern Hemisphere, as well as about the drivers of net MeHg production, hampering ecosystem modeling of Hg cycling. Mercury methylation and demethylation rates were measured in periphytic biofilms growing on submerged plants in a shallow fluvial lake located in a temperate cold region (St. Lawrence River, Quebec, Canada). Incubations were performed in situ within macrophyte beds using low-level spikes of {sup 199}HgO and Me{sup 200}Hg stable isotopes as tracers. A direct relationship was observed between K{sub m} (0.002 to 0.137 d{sup −1}) and [MeHg] in periphyton. A similar relationship was found between K{sub d} (0.096 to 0.334 d{sup −1}) and [inorganic Hg]. Periphyton of Lake St. Pierre reached high levels of net MeHg production that were two orders of magnitude higher than those found in local sediment. This production varied through the plant growing season and was mainly driven by environmental variables such as depth of growth, available light, dissolved oxygen, temperature, plant community structure, and productivity of the habitat. - Highlights: • Periphyton Hg methylation and demethylation were studied in a large fluvial lake. • Addition of stable Hg isotopes was used to obtain in situ rates for these processes. • Net methylation was higher in periphyton than in local sediments. • Methylation and demethylation rates fluctuated during the summer. • Key drivers of rates were depth, light, temperature, and community structure.

Cadmium speciation and accumulation in periphyton in a small stream with dynamic concentration variations

Energy Technology Data Exchange (ETDEWEB)

Bradac, Philippe [Eawag, Swiss Federal Institute of Aquatic Science and Technology, P.O. Box 611, CH-8600 Duebendorf (Switzerland); ETH, Swiss Federal Institute of Technology, Department of Environmental Sciences, CH-8092 Zurich (Switzerland); Wagner, Bettina; Kistler, David; Traber, Jacqueline; Behra, Renata [Eawag, Swiss Federal Institute of Aquatic Science and Technology, P.O. Box 611, CH-8600 Duebendorf (Switzerland); Sigg, Laura, E-mail: laura.sigg@eawag.c [Eawag, Swiss Federal Institute of Aquatic Science and Technology, P.O. Box 611, CH-8600 Duebendorf (Switzerland); ETH, Swiss Federal Institute of Technology, Department of Environmental Sciences, CH-8092 Zurich (Switzerland)

2010-03-15

Accumulation of cadmium in periphyton was investigated under field conditions while Cd concentration and speciation were dynamically varying in a small stream during rain events. Speciation in water was determined in situ by diffusion gradient in thin-films (DGT) and by modeling of complexation with fulvic acids. During the rain events, dissolved Cd concentrations increased from 0.17 nM to 0.27-0.36 nM, and 70-97% were DGT-labile. Cd content in periphyton closely followed Cd concentrations in water, despite higher concentrations of Zn and Mn, and may be controlled by either free or DGT-labile Cd concentrations. Decrease of Cd content in periphyton after the rain events was slower than the decrease of Cd concentration in water. Concentrations of Zn, Mn, Cu, Pb and Fe in periphyton also followed the dynamic variations of metal concentrations in water. Repeated exposure of periphyton to elevated dissolved Cd may lead to Cd accumulation. - Cadmium accumulation in periphyton was examined in a small stream during rain events in relation to Cd speciation.

Cadmium speciation and accumulation in periphyton in a small stream with dynamic concentration variations

International Nuclear Information System (INIS)

Bradac, Philippe; Wagner, Bettina; Kistler, David; Traber, Jacqueline; Behra, Renata; Sigg, Laura

2010-01-01

Accumulation of cadmium in periphyton was investigated under field conditions while Cd concentration and speciation were dynamically varying in a small stream during rain events. Speciation in water was determined in situ by diffusion gradient in thin-films (DGT) and by modeling of complexation with fulvic acids. During the rain events, dissolved Cd concentrations increased from 0.17 nM to 0.27-0.36 nM, and 70-97% were DGT-labile. Cd content in periphyton closely followed Cd concentrations in water, despite higher concentrations of Zn and Mn, and may be controlled by either free or DGT-labile Cd concentrations. Decrease of Cd content in periphyton after the rain events was slower than the decrease of Cd concentration in water. Concentrations of Zn, Mn, Cu, Pb and Fe in periphyton also followed the dynamic variations of metal concentrations in water. Repeated exposure of periphyton to elevated dissolved Cd may lead to Cd accumulation. - Cadmium accumulation in periphyton was examined in a small stream during rain events in relation to Cd speciation.

Hydrophysical conditions and periphyton in natural rivers. Analysis and predictive modelling of periphyton by changed regulations; Hydrofysiske forhold og begroing i naturlige elver. Analyse og prediktiv modellering av begroing ved reguleringsendringer

Energy Technology Data Exchange (ETDEWEB)

Stokseth, S

1994-10-01

The objective of this thesis has been to examine the interaction between hydrodynamical and physical factors and the temporal and spatial dynamics of periphyton in natural steep rivers. The study strategy has been to work with quantitative system variables to be able to evaluate the potential usability of a predictive model for periphyton changes as a response to river regulations. The thesis is constituted by a theoretical and an empirical study. The theoretical study is aimed at presenting a conceptual model of the relevant factors based on an analysis of published studies. Effort has been made to evaluate and present the background material in a structured way. To concurrently handle the spatial and temporal dynamics of periphyton a new method for data collection has been developed. A procedure for quantifying the photo registrations has been developed. The simple hydrodynamical parameters were estimated from a set of standard formulas whereas the complex parameters were estimated from a three dimensional simulation model called SSIIM. The main conclusion from the analysis is that flood events are the major controlling factors wrt. periphyton biomass and that water temperature is of major importance for the periphyton resistance. Low temperature clearly increases the periphyton erosion resistance. Thus, to model or control the temporal dynamics the river periphyton, the water temperature and the frequency and size of floods should be regarded the most significant controlling factors. The data in this study has been collected from a river with a stable water quality and frequent floods. 109 refs., 41 figs., 34 tabs.

Evidence for Interactions between Surface Water and Periphyton Biofilms in Artificial Streams

Science.gov (United States)

Studies suggest that periphyton in streambeds can harbor fecal indicator bacteria (FIB) and, under certain circumstances, can be transferred from the periphyton biofilm into the surface water. An indoor mesocosm study was conducted at the U.S. Environmental Protection Agency Expe...

Temporal and geographical distributions of epilithic sodium dodecyl sulfate-degrading bacteria in a polluted South Wales river

Energy Technology Data Exchange (ETDEWEB)

Anderson, D.J.; Day, M.J.; Russell, N.J.; White, G.F.

1988-02-01

Epilithic bacteria were isolated nonselectively from riverbed stones and examined by gel zymography for their ability to produce alkylsulfatase (AS) enzymes and thus to metabolize alkyl sulfate surfactants such as sodium dodecyl sulfate. The percentages of AS+ isolates from stone epilithon at five sites from the source to the river mouth were measured on five sampling days spread over 1 year. The results showed that (i) the prevalence of epilithic AS+ strains (as a percentage of all isolates) was much higher at polluted sites than at the source; (ii) when averaged over the whole river, percentages of AS+ strains were significantly higher at the end of summer compared with either the preceding or the following winter; (iii) analysis of site-sampling time interactions indicated that water quality factors (e.g., biochemical oxygen demand and dissolved oxygen concentration) rather than climatic factors determined the distributions of epilithic AS+ isolates; (iv) constitutive strains were the most prevalent (7.2% of all isolates), with smaller numbers of isolates with inducible (4.5%) and repressible (1.7%) enzymes.

‘Sticky business’: The influence of streambed periphyton on particle deposition and infiltration

Science.gov (United States)

Salant, Nira L.

2011-03-01

Strong feedbacks exist between physical and ecological components of aquatic systems. Aquatic plants can alter flow and sedimentation patterns, in turn influencing habitat condition and organism responses. In this study, I investigate the interactions between streambed periphyton, particle deposition and infiltration, and flow hydraulics to determine the influence of these organisms on the local environment. In a series of flume experiments, I measured the effects of two contrasting forms of periphyton at several densities and growth stages on near-bed hydraulics, particle loss from the water column, surface deposition, and subsurface infiltration. Data show that periphyton assemblages altered the rate and quantity of particle deposition via several mechanisms, including shear stress modification, surface adhesion, and bed clogging. Although trends varied for different size classes within a suspension of fine sediment, diatoms and algae had distinctly different effects on hydraulics, deposition, and infiltration. In general, diatoms increased the rate of decline in suspended particle concentrations relative to non-periphyton surfaces by reducing shear stresses and enhancing surface deposition via adhesion. Increases in diatom biomass, however, reduced the quantity and depth of particle infiltration, presumably by clogging interstitial pore spaces, in turn lowering rates of concentration decline. In contrast, all algal growth stages had slower or similar rates of concentration decline compared to non-periphyton conditions, due to partial clogging by high biomass and a lack of adhesion at the bed surface. Clogging effects were counteracted at later growth stages, however, as late-stage algal structures increased shear stresses and downward advection, in turn increasing amounts of infiltration. Compiled data from several field studies and experiments demonstrate a positive relation between periphyton biomass and inorganic mass, but also show a wide range in the

Cryptofauna of the epilithic algal matrix on an inshore coral reef, Great Barrier Reef

Science.gov (United States)

Kramer, M. J.; Bellwood, D. R.; Bellwood, O.

2012-12-01

Composed of a collection of algae, detritus, sediment and invertebrates, the epilithic algal matrix (EAM) is an abundant and ubiquitous feature of coral reefs. Despite its prevalence, there is a paucity of information regarding its associated invertebrate fauna. The cryptofaunal invertebrate community of the EAM was quantitatively investigated in Pioneer Bay on Orpheus Island, Great Barrier Reef. Using a vacuum collection method, a diversity of organisms representing 10 different phyla were identified. Crustacea dominated the samples, with harpacticoid copepods being particularly abundant (2025 ± 132 100 cm-2; mean density ± SE). The volume of coarse particulate matter in the EAM was strongly correlated with the abundance of harpacticoid copepods. The estimated biomass of harpacticoid copepods (0.48 ± 0.05 g m-2; wet weight) suggests that this group is likely to be important for reef trophodynamics and nutrient cycling.

Seasonal patterns of periphyton nitrogen fixation in calcareous wetlands

Science.gov (United States)

Liao, X.; Inglett, P.

2011-12-01

Periphyton mats are an ecologically important component of the Everglades ecosystem and plays various vital ecological functions. However, nitrogen fixation of periphyton, has received little attention throughout much of the Everglades system. The objective of this study was to characterize the seasonal pattern of periphyton N2 fixation in the Hole-in-the-Donut (HID) of Florida Everglades, where farmed marl prairie wetlands have been restored through complete soil removal (CSR) to reduce nutrient levels. Two restored areas (i.e., cleared in 2000 and 2003) and a reference (natural and unfarmed) marl prairie wetland sites were selected in the HID. Seven times of sampling were performed across the wet and dry season during the 2010 and 2011. The annual fixed nitrogen was approximately 0.4gN m-2 yr-1 in the restored sites which was higher in the reference site (~0.2gN m-2 yr-1). All the three sites showed similar seasonal patterns of N2 fixation that is higher values were observed in the wet season; but the peak value was one month later in reference sits (i.e., September) comparing to the restored areas (i.e., July). The peak of periphyton AR rates in the 2000- and 2003-restored areas appeared in July (i.e., wet season) within the range of 20-79 nmols g-1dw h-1 and 31-53nmols g-1dw h-1, respectively. In contrast, the peak of reference site was observed in September with the range of 2-5 nmols g-1dw h-1. Stable N isotopic ratios (i.e., δ15N) also varied with time but didn't show consistent seasonal pattern as nitrogen fixation. N2 fixation positively correlated with periphyton total phosphorus (TP) and negatively correlated with total nitrogen and phosphorus molar ratios (TN:TP), indicating that N2 fixation would be a indicator of nutrient limitation. In general, δ15N was negatively correlated with nitrogenase activity but the correlation became weakened in the wet season, especially in the flooded July and September, which would be explained by other environmental

Some aspects of water quality in a polluted lowland river in relation to the intracellular chemical levels in planktonic and epilithic diatoms.

Science.gov (United States)

Tien, Chien-Jung

2004-04-01

Changes in elemental concentrations of diatoms and river water from the river Erh-Jen were determined using scanning electron microscopy energy-dispersive X-ray microanalysis and inductively coupled plasma mass spectrometry. Relatively large amounts of copper and lead found in both planktonic and epilithic diatoms implied these algae might play an important role in biogeochemical cycles and in the transfer of those elements to higher trophic levels in the aquatic environment. Changes in elemental concentrations within diatom cells were found to vary with other elements within cells and the same or different elements in water. Planktonic and epilithic cells showed different correlation patterns. For epilithic diatoms, negative correlations were found between concentrations of total phosphorus and phosphate in water and those of phosphorus within cells, and between concentrations of lead in water and in cells. Concentrations of chromium and mercury within planktonic cells and those of phosphorus, manganese and lead within epilithic ones were found to be easily influenced by other elements in river water, indicating appearance of the competitive manner on uptake of such elements by algal cells. Relatively high concentration factors (CFs) for cadmium, mercury and lead by diatoms in this study suggested they are good accumulators for these heavy metals. Significant negative corrections were found between the CFs of diatoms and the concentrations of elements in river water.

Periphyton changes over 20 years of chemical recovery of Lake Orta, Italy: differential response to perturbation of littoral and pelagic communities

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Giuseppe MORABITO

2011-08-01

Full Text Available Lake Orta, a large Italian subalpine lake, has a long history of industrial pollution by acid, ammonia, and metals. A whole-lake liming treatment in 1989-1990 led to a gradual increase in pH (from 4.4 to 7 and a concomitant decline in ammonia (from 2.5 to 0.05 mg L-1 and metal concentrations (e.g., copper: from 35 to 3 μg L-1. In this study, we examine the response of the littoral zone, in terms of chemistry and periphyton assemblages, to contamination and recovery of Lake Orta. We compare these findings with a long-term data set of chemistry and phytoplankton collected in the pelagic zone. We sampled periphyton at two sites from the liming period (1989 through 2010 when the lake approached chemical equilibrium. Chemical variables collected in the littoral zone near the periphyton samples followed the same temporal trends observed in the pelagic zone. Chlorophytes, the dominant algae in the preliming period, progressively waned after the calcium carbonate addition. Diatom importance gradually increased to reach up to 80% of the total biovolume in the most recent years. There was a clear shift in the diatom taxonomic composition over the study period. Acidophilous Pinnularia subcapitata var. hilseana and metal-tolerant Achnanthes minutissima were dominant before liming. With the progressive increase in pH and decline in metal concentrations, there was successively the dominance of Fragilaria nanoides (formerly identified as Synedra tenera and Cymbella microcephala in the transition period and of circumneutral Navicula cryptocephala, N. radiosa, and Synedra ulna in the most recent period. Pelagic diatoms were more affected than benthic diatoms by the industrial pollution and their recovery after the liming intervention was slower. Whereas present periphyton diatom assemblages are similar to those observed in nearby unpolluted Lake Mergozzo, pelagic assemblages are still in transition from severe disturbance towards characteristics reported before

Short-term effects of medetomidine on photosynthesis and protein synthesis in periphyton, epipsammon and plankton communities in relation to predicted environmental concentrations.

Science.gov (United States)

Ohlauson, Cecilia; Eriksson, Karl Martin; Blanck, Hans

2012-01-01

Medetomidine is a new antifouling substance, highly effective against barnacles. As part of a thorough ecotoxicological evaluation of medetomidine, its short-term effects on algal and bacterial communities were investigated and environmental concentrations were predicted with the MAMPEC model. Photosynthesis and bacterial protein synthesis for three marine communities, viz. periphyton, epipsammon and plankton were used as effect indicators, and compared with the predicted environmental concentrations (PECs). The plankton community showed a significant decrease in photosynthetic activity of 16% at 2 mg l⁻¹ of medetomidine, which was the only significant effect observed. PECs were estimated for a harbor, shipping lane and marina environment using three different model scenarios (MAMPEC default, Baltic and OECD scenarios). The highest PEC of 57 ng l⁻¹, generated for a marina with the Baltic scenario, was at least 10,000-fold lower than the concentration that significantly decreased photosynthetic activity. It is concluded that medetomidine does not cause any acute toxic effects on bacterial protein synthesis and only small acute effects on photosynthesis at high concentrations in marine microbial communities. It is also concluded that the hazard from medetomidine on these processes is low since the effect levels are much lower than the highest PEC.

Effects of nutrients and fish on periphyton and plant biomass across a European latitudinal gradient

NARCIS (Netherlands)

Bécares, E.; Gomá, J.; Fernández-Aláez, M.; Fernández-Aláez, C.; Romo, S.; Rosa Miracle, M.; Ståhl-Delbanco, A.; Hansson, L-A.; Gyllström, M.; van de Bund, W.; Van Donk, E.; Kairesalo, T.; Hietala, J.; Stephen, D.; Balayla, D.; Moss, B.

2008-01-01

Replicated, factorial mesocosm experiments were conducted across Europe to study the effects of nutrient enrichment and fish density on macrophytes and on periphyton chlorophyll a (chl-a) with regard to latitude. Periphyton chl-a densities and plant decline were significantly related to nutrient

The Effect of Zebra Mussels on Algal Community Structure in an Impounded River System

Science.gov (United States)

Trumble, A. F.; Luttenton, M.

2005-05-01

The zebra mussel, Dreissena polymorpha, invaded the Great Lakes Region in the mid 1980's, and subsequently colonized inland lakes and coastal river systems through secondary invasions. The Muskegon River below Croton Dam was colonized by zebra mussels in 2000 following their introduction into Croton impoundment in the late 1990's. No zebra mussels were found below Croton Dam in 1999 but had increased to 25,000 m-2 by 2001. We examined the affect of zebra mussels on epilithic periphyton communities by comparing plots that were and were not colonized by zebra mussels. Chlorophyll a increased in both treatments over time but was significantly higher in control plots than in zebra mussel plots. The concentration of chlorophyll a in the control plots increased from 14 µgcm-2 to 26 µgcm-2 and the concentration in the zebra mussel plots started at 12 µgcm-2, peaked at 19 µgcm-2, and then decreased to 15 µgcm-2 over a 6 week period. In a related experiment using artificial streams, chlorophyll a increased with increasing zebra mussel density, but differences were not significant. The different trends observed between the two experiments may be explained in part by arthropod invertebrates associated with zebra mussel populations.

Composition, Occurrences and Checklist of Periphyton Algae of ...

African Journals Online (AJOL)

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The periphyton is also an important indicator of water quality (Azim et al, 2006). Attached algae are primitive plants that get their nutrients from water passing over them. ... rung in the aquatic food chain depend directly ... influence of sea water.

Mixed culture of tilapia (Oreochromis niloticus) and freshwater prawn (Macrobrachium rosenbergii) in periphyton-based ponds

NARCIS (Netherlands)

Uddin, S.

2007-01-01

In recent years, the concept of periphyton-based aquaculture has been tested and applied in aquaculture. Positive effects of substrate addition for periphyton development included increasing the food supply and providing shelter for culture animals. The aim of this project was to develop a low-cost

Periphyton crops and productivity in a reactor thermal effluent

International Nuclear Information System (INIS)

Tilly, L.J.

1975-01-01

Samples of periphyton grown for two weeks on microscope slides in surface waters of the reactor cooling reservoir, Par Pond, were examined for differences in species composition, diversity, standing crop, and 14 C uptake relatable to 7 positions in the thermal effluent. For stations which differed in average temperature by less than 5 0 C, weight specific productivity differed by a factor of 7. Periphyton biomass differed more than fivefold between stations 5.5 0 C apart. For most incubation intervals, both weight specific productivity and accumulated crop correlated highly with the average growing temperature, but slopes of regressions from consecutive periods often differed greatly while species composition and temperauture regime changed only slightly. Recent experiments indicate that observed differences may be due to interactions between nutrients and temperatures. (U.S.)

Comparison of Cultural and Molecular Fecal Indicator Measurements in Surface Water and Periphyton Biofilms in Artificial Streams

Science.gov (United States)

Studies suggest that periphyton in streambeds can harbor fecal indicator bacteria (FIB) and, under certain circumstances, can be transferred from the periphyton biofilm into the surface water. An indoor mesocosm study was conducted at the U.S. Environmental Protection Agency Expe...

Epilithic algae from caves of the Krakowsko-Częstochowska Upland (Southern Poland

Directory of Open Access Journals (Sweden)

Joanna Czerwik-Marcinkowska

2011-01-01

Full Text Available This paper describes the first study of algae assemblages in 20 caves in the Krakowsko-Częstochowska Upland (Southern Poland, in the period between 2005-2006. The investigations showed mostly on epilithic algae and their subaeric habitats (rock faces within caves and walls at cave entrances. The morphological and cytological variability of algae were studied in fresh samples, in cultures grown on agar plates and in SPURR preparations. A total of 43 algae species was identified, mostly epilithic species and tolerant of low light intensities. The largest group was formed by representatives of the division Chlorophyta (24 species, and then the division Chrysophyta (Heterokontophyta - 17 species, with 9 species belonging to the class Bacillariophyceae, 7 species - Xanthophyceae and 1 species representing the class Eustigmatophyceae. Dinophyta (2 species constituted the last and the smallest group. Among the collected algae, the following species deserve special attention: Thelesphaera alpina, Bracteacoccus minor, Trachychloron simplex, Tetracystis intermedia and T. cf. isobilateralis. The last species was not earlier found in Europe. Identification of species was greatly aided by examination of cell ultrastructure, which provided an array of further features, increasing chances of correct species identification. Furthermore, the studies focused that algae, although usually remaining under dominance of cyanobacteria, excellently differentiate this special area and even enrich it.

Experimental investigations for controlling periphyton in regulated rivers; Eksperimentelle undersoekelser for kontroll av begroing i regulerte vassdrag

Energy Technology Data Exchange (ETDEWEB)

Lindstroem, E A; Bremnes, T; Johansen, S W

1994-12-31

Regulation of river courses may have several environmental effects. This report describes investigations in NIVA`s experimental troughs near Oset, Maridalsvannet, Oslo, Norway. The main topic is algae periphyton and benthic invertebrates, with different emphasis on the different components. In 1989 the problem of ``the impact of benthic invertebrates on algae periphyton`` was illuminated, and In 1990 the converse, ``the impact of algae periphyton on benthic invertebrates`` as well as the effects of various additives of readily available phosphorus on algae periphyton. It is found that small additions of phosphorus (0.5 {mu}g P/l) may lay the foundation for a dramatic increase in growth rate and biomass. Some groups of benthic invertebrates responded quickly to the increased mass of algae. In 1991 the research was concentrated on establishing algae periphyton over a long time, at various temperatures, with and without the addition of phosphorus. The results of three years of research form, with similar results from the literature, the foundation of certain conclusions about the conditions for the establishment of algae mass in running water. The report states five levels of phosphorus concentration which may develop different levels of biomass. At the highest levels the size of the biomass is described as ``problematic``. 100 refs., 55 figs., 97 tabs.

Effects of organic pollution on biological communities of marine biofilm on hard substrata.

Science.gov (United States)

Sanz-Lázaro, C; Fodelianakis, S; Guerrero-Meseguer, L; Marín, A; Karakassis, I

2015-06-01

We examined the effect of organic enrichment on diatom and bacterial assemblages of marine epilithic biofilms on two locations in the Mediterranean, one situated in Spain and the other in Greece. Total organic carbon, total organic nitrogen, stable isotopes (δ(13)C and δ(15)N) and chlorophyll a indicated significant incorporation of organic wastes, increased primary production and trophic niche modifications on the biofilms close to the organic enrichment source. In Spain, where the organic load was higher than in Greece, diatom and, to some extent, bacterial assemblages varied following the organic enrichment gradient. The taxonomic richness of diatom and bacterial communities was not influenced by organic enrichment. Classical community parameters showed consistent patterns to organic pollution in both locations, whereas community assemblages were only influenced when organic pollution was greatest. The successional patterns of these communities were similar to other epilithic communities. The modification of community assemblages induced by organic pollution may affect ecological functions. Copyright © 2015 Elsevier Ltd. All rights reserved.

Nonlinear Relationship of Near-Bed Velocity and Growth of Riverbed Periphyton

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Mohamed Ateia

2016-10-01

Full Text Available Artificial streams were set up to test the relationship between near-bed water velocity and periphyton growth. Periphyton community samples collected from a Japanese stream were incubated for 44 days under a light intensity of 252 ± 72 μmol·photons/m2·s, a temperature of 20–25 °C, and three near-bed water velocity classes: low (<17.9 cm/s, moderate (17.9–32.8 cm/s, and high (>32.8 cm/s. A logistic model was applied to estimate the maximum net growth rate (μmax and carrying capacity (Bmax. A response surface method was also applied to estimate chlorophyll a (Chl-a and ash-free dry mass (AFDM with respect to the independent variables (i.e., time and water velocity. We detected both the highest μmax (1.99 d−1 and highest Bmax (7.01 mg/m2 for Chl-a at the moderate water velocity. For AFDM, we observed the highest μmax (0.57 d−1 and Bmax (1.47 g/m2 at the low and moderate velocity classes, respectively. The total algae density in the region of moderate velocity at the end of the experiment was 6.47 × 103 cells/cm2, corresponding to levels 1.7 and 1.3 times higher than those at lower and higher velocities, respectively. Our findings indicated that the moderate near-bed water velocity provided favorable conditions for algal growth and corresponding biomass accumulation.

Comparing two periphyton collection methods commonly used for stream bioassessment and the development of numeric nutrient standards.

Science.gov (United States)

Rodman, Ashley R; Scott, J Thad

2017-07-01

Periphyton is an important component of stream bioassessment, yet methods for quantifying periphyton biomass can differ substantially. A case study within the Arkansas Ozarks is presented to demonstrate the potential for linking chlorophyll-a (chl-a) and ash-free dry mass (AFDM) data sets amassed using two frequently used periphyton sampling protocols. Method A involved collecting periphyton from a known area on the top surface of variably sized rocks gathered from relatively swift-velocity riffles without discerning canopy cover. Method B involved collecting periphyton from the entire top surface of cobbles systematically gathered from riffle-run habitat where canopy cover was intentionally avoided. Chl-a and AFDM measurements were not different between methods (p = 0.123 and p = 0.550, respectively), and there was no interaction between method and time in the repeated measures structure of the study. However, significantly different seasonal distinctions were observed for chl-a and AFDM from all streams when data from the methods were combined (p methods may effectively be used together with some minor considerations due to potential confounding factors. This study provides motivation for the continued investigation of combining data sets derived from multiple methods of data collection, which could be useful in stream bioassessment and particularly important for the development of regional stream nutrient criteria for the southern Ozarks.

Cyanobacteria enhance methylmercury production: a hypothesis tested in the periphyton of two lakes in the Pantanal floodplain, Brazil.

Science.gov (United States)

Lázaro, Wilkinson L; Guimarães, Jean Remy D; Ignácio, Aurea R A; Da Silva, Carolina J; Díez, Sergi

2013-07-01

The toxic potential of mercury (Hg) in aquatic systems is due to the presence and production of methylmercury (MeHg). Recent studies in tropical floodplain environments showed that periphyton associated with the roots of aquatic macrophytes produce MeHg. Periphyton communities are the first link in the food chain and one of the main MeHg sources in aquatic environments. The aim of this work was to test the hypotheses that the algal community structure affects potential methylation, and ecologically distinct communities with different algal and bacterial densities directly affect the formation of MeHg in the roots of macrophytes. To evaluate these, net MeHg production in the roots of Eichhornia crassipes in relation to the taxonomic structure of associated periphytic algae was evaluated. Macrophyte root samples were collected in the dry and flood season from two floodplain lakes in the Pantanal (Brazil). These lakes have different ecological conditions as a function of their lateral hydrological connectivity with the Paraguay River that is different during times of drought. Results indicated that MeHg production was higher in the flood season than in the dry season. MeHg production rates were higher in the disconnected lake in comparison to the connected lake during the dry season. MeHg production exhibited a strong positive co-variation with cyanobacteria abundance (R(2)=0.78; pcyanobacteria are associated with higher rates of methylation in aquatic systems. This suggests that cyanobacteria could be a proxy for sites of MeHg production in some natural aquatic environments. Copyright © 2013 Elsevier B.V. All rights reserved.

The effects of periphyton, fish and fertilizer dose on biological processes affecting water quality in earthen fish ponds.

NARCIS (Netherlands)

Milstein, A.; Azim, M.E.; Wahab, M.A.; Verdegem, M.C.J.

2003-01-01

The potential of periphyton-based aquaculture in South Asia is under investigation in an extensive research program. This paper is a further analysis of data from four experiments carried out in that framework, to explore periphyton, fish and fertilizer dose effects on water quality. Factor analysis

Spatial and temporal variations of Cocconeis placentula var. euglypta (Ehrenb. 1854 Grunow, 1884 in drift and periphyton

Directory of Open Access Journals (Sweden)

EN. Gari

Full Text Available Spatial and temporal variations of Cocconeis placentula var. euglypta in drift and periphyton were studied in mountain streams of the Córdoba Province (Argentina. The sampling program was conducted in study sites located on a confluence between different order streams during an annual cycle. Samples were also taken every two hours during the daylight period in high and low water conditions. The relationship between drift and cellular reproduction was evaluated by valve length biometrics analysis. C. placentula var. euglypta drift was continuous; its density was not always dependent on periphyton density in each locality. C. placentula var. euglypta drift could be related to abiotic factors such as temperature and flow during the annual cycle. There were significant differences between periphyton and drift valve lengths. Moreover, drift can be associated with cellular reproduction because density was higher when valve lengths were shorter at different hours of the day. C. placentula var. euglypta epiphytims on Cladophora glomerata also influenced drift density and size distribution, modifying the relationship between periphyton and drift during the late spring when C. placentula var. euglypta was detached from senescent mats.

EXPERIMENTAL EFFECTS OF CONDUCTIVITY AND MAJOR IONS ON STREAM PERIPHYTON - abstract

Science.gov (United States)

Our study examined if specific conductivities comprised of different ions associated with resource extraction affected stream periphyton assemblages, which are important sources of primary production. Sixteen artificial streams were dosed with two ion recipes intended to mimic so...

Water quality in simulated eutrophic shallow lakes in the presence of periphyton under different flow conditions.

Science.gov (United States)

Chen, Shu; Yang, Guolu; Lu, Jing; Wang, Lei

2018-02-01

Although the effects of periphyton on water quality and its relationship with flow conditions have been studied by researchers, our understanding about their combined action in eutrophic shallow lakes is poor. In this research, four aquatic model ecosystems with different water circulation rates and hydraulic conditions were constructed to investigate the effect of periphyton and flow condition on water quality. The concentrations of NH 4 + , TP, and chlorophyll-a and flow conditions were determined. The results show that, as a result of the rising nutrient level at the early stage and the decline in the lower limit, the presence of periphyton can make the ecosystem adaptable to a wider range of nutrients concentration. In terms of the flow condition, the circulation rate and hydraulic condition are influential factors for aquatic ecosystem. Higher circulation rate in the ecosystem, on one hand, facilitates the metabolism by accelerating nutrient cycling which is beneficial to water quality; on the other hand, high circulation rate leads to the nutrient lower limit rising which is harmful to water quality improvement. At low velocities, slight differences in hydraulic conditions, vertical velocity gradient and turbulence intensity gradient could affect the quantity of phytoplankton. Our study suggests that, considering environmental effect of periphyton, flow conditions and their combined action is essential for water quality improvement and ecological restoration in eutrophic shallow lakes.

Periphyton density is similar on native and non-native plant species

NARCIS (Netherlands)

Grutters, B.M.C.; Gross, Elisabeth M.; van Donk, E.; Bakker, E.S.

2017-01-01

Non-native plants increasingly dominate the vegetation in aquatic ecosystems and thrive in eutrophic conditions. In eutrophic conditions, submerged plants risk being overgrown by epiphytic algae; however, if non-native plants are less susceptible to periphyton than natives, this would contribute to

Pollution-Induced Community Tolerance To Diagnose Hazardous Chemicals in Multiple Contaminated Aquatic Systems.

Science.gov (United States)

Rotter, Stefanie; Gunold, Roman; Mothes, Sibylle; Paschke, Albrecht; Brack, Werner; Altenburger, Rolf; Schmitt-Jansen, Mechthild

2015-08-18

Aquatic ecosystems are often contaminated with large numbers of chemicals, which cannot be sufficiently addressed by chemical target analyses. Effect-directed analysis (EDA) enables the identification of toxicants in complex contaminated environmental samples. This study suggests pollution-induced community tolerance (PICT) as a confirmation tool for EDA to identify contaminants which actually impact on local communities. The effects of three phytotoxic compounds local periphyton communities, cultivated at a reference (R-site) and a polluted site (P-site), were assessed to confirm the findings of a former EDA study on sediments. The sensitivities of R- and P-communities to prometryn, tributyltin (TBT) and N-phenyl-2-naphthylamine (PNA) were quantified in short-term toxicity tests and exposure concentrations were determined. Prometryn and PNA concentrations were significantly higher at the P-site, whereas TBT concentrations were in the same range at both sites. Periphyton communities differed in biomass, but algal class composition and diatom diversity were similar. Community tolerance of P-communities was significantly enhanced for prometryn, but not for PNA and TBT, confirming site-specific effects on local periphyton for prometryn only. Thus, PICT enables in situ effect confirmation of phytotoxic compounds at the community level and seems to be suitable to support confirmation and enhance ecological realism of EDA.

Community-Level Analysis of psbA Gene Sequences and Irgarol Tolerance in Marine Periphyton▿

Science.gov (United States)

Eriksson, K. M.; Clarke, A. K.; Franzen, L.-G.; Kuylenstierna, M.; Martinez, K.; Blanck, H.

2009-01-01

This study analyzes psbA gene sequences, predicted D1 protein sequences, species relative abundance, and pollution-induced community tolerance in marine periphyton communities exposed to the antifouling compound Irgarol 1051. The mechanism of action of Irgarol is the inhibition of photosynthetic electron transport at photosystem II by binding to the D1 protein. The metagenome of the communities was used to produce clone libraries containing fragments of the psbA gene encoding the D1 protein. Community tolerance was quantified with a short-term test for the inhibition of photosynthesis. The communities were established in a continuous flow of natural seawater through microcosms with or without added Irgarol. The selection pressure from Irgarol resulted in an altered species composition and an inducted community tolerance to Irgarol. Moreover, there was a very high diversity in the psbA gene sequences in the periphyton, and the composition of psbA and D1 fragments within the communities was dramatically altered by increased Irgarol exposure. Even though tolerance to this type of compound in land plants often depends on a single amino acid substitution (Ser264→Gly) in the D1 protein, this was not the case for marine periphyton species. Instead, the tolerance mechanism likely involves increased degradation of D1. When we compared sequences from low and high Irgarol exposure, differences in nonconserved amino acids were found only in the so-called PEST region of D1, which is involved in regulating its degradation. Our results suggest that environmental contamination with Irgarol has led to selection for high-turnover D1 proteins in marine periphyton communities at the west coast of Sweden. PMID:19088321

Temporal changes in periphytic meiofauna in lakes of different trophic states

Directory of Open Access Journals (Sweden)

Kurt Pettersson

2012-01-01

Full Text Available Meiofaunal organisms in the periphyton of stony hard-substrates (epilithon were studied in three Swedish lakes with different trophic states (oligo-, meso- and eutrophic with respect to seasonal successions in abundance, biomass, and production. Over a period of 2 years, the meiofaunal population of all three lakes fluctuated greatly, with densities varying up to nine-fold within a season. In the oligotrophic lake, a significant decrease in meiofauna in winter was striking, whereas in the other two lakes, richer in nutrients, there was a pronounced peak in early summer. Although the lakes, on average, did not differ in epilithic organic and inorganic material, the differences in meiofaunal abundance, biomass, and production were significant. Correlation analysis revealed that altogether the meiofaunal biomass was positively related to the lakes’ trophic state (total phosphorus, while the meiofaunal abundance and production along the trophic spectrum displayed a humped-shape distribution, with maximum values measured in the mesotrophic Lake Erken (1324 ind cm-2 and 2249 mg DW cm-2 y-1. Nematodes were the dominant meiofaunal group in the epilithon of all three lakes, accounting for up to 58% in abundance, 33% in biomass and 55% in production of the whole meiofaunal community. However, their relative importance tended to decrease with increasing trophic state. Beside nematodes, rotifers, oligochaetes, copepods and tardigrades were also found in large numbers in the epilithon. Overall, the results demonstrated that, due to their high abundance, biomass, and production, meiofaunal organisms play an important role in epilithic communities.

Notes on epilithic and epigeic lichens from granite and gneiss outcrops in mountains of Makedonia, Greece, with emphasis on northern species

DEFF Research Database (Denmark)

Christensen, Steen

2014-01-01

The epilithic and epigeic lichen flora of eight localities with granite and gneiss outcrops in the mountains of Makedonia, N Greece has been investigated. Of the 46 taxa reported, seven species are new to Greece, viz.: Brodoa oroarcti­ca, Candelariella coralliza, Cetraria ericetorum, Lecanora...

Succession of Periphyton and Phytoplankton Assemblages in Years with Varying Amounts of Precipitation in a Shallow Urban Lake (Lake Jeziorak Mały, Poland)

OpenAIRE

Zębek Elžbieta

2014-01-01

This study of periphyton assemblages (periphyton in separator pipes, epilithon and epiphyton) and phytoplankton was carried out in Lake Jeziorak Maly in 1997-2003 and 2005. Since precipitation amounts varied in these years, changes in the abundance, biomass, taxonomic group structure, spe-cies diversity and dominant taxa of these assemblages were analyzed in relation to the physical and chemical water parameters. The periphyton in pipes had their highest abundance and biomass at the mean prec...

Light modulated toxicity of isoproturon toward natural stream periphyton photosynthesis: a comparison between constant and dynamic light conditions.

Science.gov (United States)

Laviale, Martin; Prygiel, Jean; Créach, Anne

2010-05-10

This study tested if a variation in light intensity, in comparison to constant light required in well-designed toxicity test, could have measurable consequences on the sensitivity of phototrophic biofilms (periphyton) to isoproturon. Two independent experiments were carried out to investigate the combined effects of light and isoproturon on the photochemical behavior of intact natural biofilms by measurements of chlorophyll fluorescence and pigment composition. Experiment 1 consisted of exposing biofilms to series of isoproturon concentrations (0-2 mg L(-1)) for 7 h under constant light at different irradiance levels (25-300 micromol m(-2) s(-1)). In experiment 2, biofilms were exposed using more environmentally realistic conditions to three selected concentrations of isoproturon (2, 6 and 20 microg L(-1)) during a 7-h-simulated daily light cycle. Our results demonstrated that light, considered here as a direct physical stressor, slightly modulated the acute toxicity of isoproturon on these diatom dominated communities. This was attributed to the fact that these two factors act specifically on the photosynthetic activity. Furthermore, it was shown that a dynamic light regime increased periphyton sensitivity to isoproturon by challenging its photoprotective mechanisms such as the xanthophyll cycle, therefore implying that traditional ecotoxicological bioassays lead to underestimate the effect of isoproturon. 2010 Elsevier B.V. All rights reserved.

Twenty-five-year study of radionuclides in the Susquehanna river via periphyton biomonitors.

Science.gov (United States)

Patrick, Ruth; Palms, John; Kreeger, Danielle; Harris, Charles

2007-01-01

This 25-y study monitored aquatic and terrestrial gamma-ray-emitting radionuclide levels near a nuclear power plant. It is the only known, long-term environmental survey of its kind. It was conducted neither by a utility owner, nor by a government agency, but rather by a private, environmental research institution. Compared to dozens of other flora and fauna, periphyton was found to be the best indicator to biomonitor the Susquehanna River, which runs near PPL Susquehanna's nuclear plant. Sampling began in 1979 before the first plant start-up and continued for the next 24 years. Monitoring began two months after the Three Mile Island accident of 28 March 1979 and includes Three Mile Island area measurements. Ongoing measurements detected fallout from Chernobyl in 1986, as well as I not released from PPL Susquehanna. Although this paper concentrates on radionuclides found in periphyton, the scope of the entire environmental program includes a wide variety of aquatic and land-based plants, animals, and inorganic matter. Other species and matter studied were fish, mussels, snails, crayfish, insects, humus, mushrooms, lichens, squirrels, deer, cabbage, tomatoes, coarse and flocculated sediment, and more. Results show periphyton works well for detection of radionuclide activity, even in concentrations less than 100 Bq kg (picocuries per gram amounts). Data indicate that PPL Susquehanna's radionuclide releases have had no known environmental or human health impact.

EFFECTS OF A COASTAL GOLF COMPLEX ON WATER QUALITY, PERIPHYTON, AND SEAGRASS.

Science.gov (United States)

The objective of this study was to determine the effects of a golf course complex on water quality, colonized periphyton and seagrass meadows in adjacent freshwater, near-coastal and wetland areas. The environmental impact of the recreational facility, which uses spray wastewater...

Effects of cadmium stress and sorption kinetics on tropical freshwater periphytic communities in indoor mesocosm experiments

International Nuclear Information System (INIS)

Bere, Taurai; Tundisi, José Galizia

2012-01-01

Understanding the cause and effect relationship between stressors and biota is crucial for the effective management, restoration and preservation of aquatic systems. The objective of the present study was to assess the effects of five Cd concentrations on tropical periphyton community growth, Cd accumulation kinetics, as well as the effects of Cd on diatom community structure and composition. Natural periphyton communities were transferred to artificial stream chambers and exposed to Cd concentrations of 0.005, 0.01, 0.03, 0.05 and 0.1 mg.L −1 . Metal accumulation (total and intracellular) in biofilms, dry weight and ash-free dry mass, growth rate, algal cell density and diatom community composition were analysed on samples collected after 1, 2 and 4 weeks of colonization. Periphyton growth and development were significantly lowered by Cd concentrations > 0.03 mg.L −1 . High Cd accumulation capacity by periphyton was demonstrated with total and intracellular Cd content in biofilms reflecting the effects of concentrations of Cd in the culture media and exposure duration. Total and intracellular Cd content generally increased in treatments in the order 0.005 −1 at any sampling time with increasing level of accumulated Cd with duration of exposure in all the systems. Shifts in species composition (development of more resistant species like Achnanthidium minutissimum and reduction of sensitive ones like Diatoma vulgare, Navicula viridula and Navicula cryptocephala), decreases in species richness and diversity and morphological alterations (deformities) of diatom cells with increasing Cd concentration and exposure duration were observed. The results give valuable information on Cd impact of freshwater biofilms. -- Highlights: ► We investigated toxicity and sorption kinetics of Cd on periphyton communities. ► [Cd] > 0.03 mg.L −1 lowers growth. ► Absorbed Cd was a function of duration of exposure and [Cd]. ► Changes in community composition were recorded

Effects of cadmium stress and sorption kinetics on tropical freshwater periphytic communities in indoor mesocosm experiments

Energy Technology Data Exchange (ETDEWEB)

Bere, Taurai, E-mail: taubere@yahoo.com [Instituto Internacional de Ecologia, Rua Bento Carlos, 750, Centro, Sao Carlos, Sao Paulo (Brazil); Universidade Federal De Sao Carlosm, Programa de Pos-Graduacao em Ecologia e Recursos Naturais, Rodovia Washington Luis, km 235, SP-310, Sao Carlos, Sao Paulo (Brazil); Tundisi, Jose Galizia [Instituto Internacional de Ecologia, Rua Bento Carlos, 750, Centro, Sao Carlos, Sao Paulo (Brazil)

2012-08-15

Understanding the cause and effect relationship between stressors and biota is crucial for the effective management, restoration and preservation of aquatic systems. The objective of the present study was to assess the effects of five Cd concentrations on tropical periphyton community growth, Cd accumulation kinetics, as well as the effects of Cd on diatom community structure and composition. Natural periphyton communities were transferred to artificial stream chambers and exposed to Cd concentrations of 0.005, 0.01, 0.03, 0.05 and 0.1 mg.L{sup -1}. Metal accumulation (total and intracellular) in biofilms, dry weight and ash-free dry mass, growth rate, algal cell density and diatom community composition were analysed on samples collected after 1, 2 and 4 weeks of colonization. Periphyton growth and development were significantly lowered by Cd concentrations > 0.03 mg.L{sup -1}. High Cd accumulation capacity by periphyton was demonstrated with total and intracellular Cd content in biofilms reflecting the effects of concentrations of Cd in the culture media and exposure duration. Total and intracellular Cd content generally increased in treatments in the order 0.005 < 0.01 < 0.03 < 0.05 < 0.1 mg.L{sup -1} at any sampling time with increasing level of accumulated Cd with duration of exposure in all the systems. Shifts in species composition (development of more resistant species like Achnanthidium minutissimum and reduction of sensitive ones like Diatoma vulgare, Navicula viridula and Navicula cryptocephala), decreases in species richness and diversity and morphological alterations (deformities) of diatom cells with increasing Cd concentration and exposure duration were observed. The results give valuable information on Cd impact of freshwater biofilms. -- Highlights: Black-Right-Pointing-Pointer We investigated toxicity and sorption kinetics of Cd on periphyton communities. Black-Right-Pointing-Pointer [Cd] > 0.03 mg.L{sup -1} lowers growth. Black

Effects of organic pollution on biological communities of marine biofilm on hard substrata

International Nuclear Information System (INIS)

Sanz-Lázaro, C.; Fodelianakis, S.; Guerrero-Meseguer, L.; Marín, A.; Karakassis, I.

2015-01-01

We examined the effect of organic enrichment on diatom and bacterial assemblages of marine epilithic biofilms on two locations in the Mediterranean, one situated in Spain and the other in Greece. Total organic carbon, total organic nitrogen, stable isotopes (δ 13 C and δ 15 N) and chlorophyll a indicated significant incorporation of organic wastes, increased primary production and trophic niche modifications on the biofilms close to the organic enrichment source. In Spain, where the organic load was higher than in Greece, diatom and, to some extent, bacterial assemblages varied following the organic enrichment gradient. The taxonomic richness of diatom and bacterial communities was not influenced by organic enrichment. Classical community parameters showed consistent patterns to organic pollution in both locations, whereas community assemblages were only influenced when organic pollution was greatest. The successional patterns of these communities were similar to other epilithic communities. The modification of community assemblages induced by organic pollution may affect ecological functions. - Highlights: • We examined the effect of organic enrichment on assemblages of marine biofilms. • Classical community parameters showed consistent patterns to organic pollution. • Diatom and bacterial assemblages were affected under high level of organic enrichment. • Successional patterns were similar to other communities inhabiting hard substrata. • Assemblage modifications induced by organic pollution may affect ecological functions. - Organic pollution modifies the assemblages of biofilm communities which may affect important ecological functions

Cadmium bioavailability to Hyalella azteca from a periphyton diet compared to an artificial diet and application of a biokinetic model

Energy Technology Data Exchange (ETDEWEB)

Golding, Lisa A., E-mail: lisa.golding@csiro.au [Department of Biology, University of Waterloo, Waterloo, Ontario N2L 3G1 (Canada); Borgmann, Uwe [Environment Canada, 867 Lakeshore Road, Burlington, Ontario L7R 4A6 (Canada); George Dixon, D. [Department of Biology, University of Waterloo, Waterloo, Ontario N2L 3G1 (Canada)

2013-01-15

Differences between the bioavailability of cadmium in a periphyton diet and an artificial laboratory diet (TetraMin{sup Registered-Sign }) have important consequences for predicting bioaccumulation and toxicity in the freshwater amphipod Hyalella azteca. The assimilation efficiency (AE) of Cd was compared between periphyton and TetraMin{sup Registered-Sign} at low (1510 and 358 nmol/g ash-free dry mass respectively) and chronically lethal (31,200 and 2890 nmol/g ash-free dry mass respectively) Cd concentrations and in fresh and dry forms using a {sup 109}Cd radiotracer pulse-chase feeding technique. Assimilation efficiency of Cd from periphyton (AE = 3-14%) was lower than that for TetraMin{sup Registered-Sign} (AE = 44-86%) regardless of Cd concentration or food form. Ingestion rate (IR) was lower for dry than fresh forms of periphyton (0.042 and 0.16 g AFDM/g H. azteca/day respectively) and TetraMin{sup Registered-Sign} (0.19 and 0.87 AFDM/g H. azteca/day respectively) and depuration rate (k{sub e}) did not differ statistically with food type, form or Cd concentration (0.032-0.094 d{sup -1}). Biokinetic models with parameters of AE, IR and k{sub e} were used to estimate bioaccumulation from the separate food types. These estimates were compared to those from an independent chronic Cd saturation bioaccumulation model. While the model estimates did not concur, a sensitivity analysis indicated that AE and IR were the most influential biokinetic model parameters for Cd in periphyton and TetraMin{sup Registered-Sign} respectively. It was hypothesized that AE was underestimated for Cd in periphyton due to a non-adapted gut enzyme system and IR was overestimated for Cd in TetraMin{sup Registered-Sign} due to an initial rapid ingestion phase in H. azteca's feeding habits. This research demonstrated the importance of using ecologically relevant food types in laboratory experiments and verifying acute biokinetic model predictions of dietary metal contribution with

Community-level microalgal toxicity assessment by multiwavelength-excitation PAM fluorometry

International Nuclear Information System (INIS)

Schmitt-Jansen, Mechthild; Altenburger, Rolf

2008-01-01

In ecotoxicological studies involving community-level investigations, rapid and multiparametric fluorescence-based methods may provide substantial advantages over traditional methods used for structural and functional community analysis. Therefore, multiwavelength-excitation pulse-amplitude modulated (PAM) fluorometry was applied in this study to assess long-term changes in periphyton community structure, short-term effects on periphyton functioning (photosynthesis) and pollution induced community tolerance (PICT). For inter-calibration, periphyton structure was evaluated by chemotaxonomic analysis of accessory pigments and a four-wavelength-excitation PAM fluorometer. Short-term effects of herbicides were evaluated by fluorescence quenching analysis and 14 C-incorporation as a proxy of primary production. Subsequently, the method was applied to assess structural and functional changes in periphyton communities after isoproturon exposure for 14 and 26 days, respectively. Results showed good correlation of the PAM fluorescence-based measurements with traditional methods for biofilms in the initial colonisation phase for structural and functional parameters. However, for biofilms older than 9 weeks PAM fluorescence may underestimate biomass. Multiwavelength-excitation PAM fluorometry showed good correlation with marker pigment concentrations indicating that this method provides a reliable estimate of the community structure. PAM fluorometry was able to quantify changes of biomass and follow relative shifts in class composition of biofilms under exposure of isoproturon. Short-term tests based on the quantification of the inhibition of the effective quantum yield revealed a concentration-dependent increase of PICT. The observation of two succession phases of the biofilms after 14 and 26 days of growth, respectively, revealed that sensitivity of biofilms decreased with increasing age and biomass, respectively, but PICT remained a characteristic parameter of exposed

Community-level microalgal toxicity assessment by multiwavelength-excitation PAM fluorometry

Energy Technology Data Exchange (ETDEWEB)

Schmitt-Jansen, Mechthild [UFZ-Helmholtz Centre for Environmental Research, Department of Bioanalytical Ecotoxicology, Permoserstr. 15, 04318 Leipzig (Germany)], E-mail: Mechthild.Schmitt@ufz.de; Altenburger, Rolf [UFZ-Helmholtz Centre for Environmental Research, Department of Bioanalytical Ecotoxicology, Permoserstr. 15, 04318 Leipzig (Germany)

2008-01-20

In ecotoxicological studies involving community-level investigations, rapid and multiparametric fluorescence-based methods may provide substantial advantages over traditional methods used for structural and functional community analysis. Therefore, multiwavelength-excitation pulse-amplitude modulated (PAM) fluorometry was applied in this study to assess long-term changes in periphyton community structure, short-term effects on periphyton functioning (photosynthesis) and pollution induced community tolerance (PICT). For inter-calibration, periphyton structure was evaluated by chemotaxonomic analysis of accessory pigments and a four-wavelength-excitation PAM fluorometer. Short-term effects of herbicides were evaluated by fluorescence quenching analysis and {sup 14}C-incorporation as a proxy of primary production. Subsequently, the method was applied to assess structural and functional changes in periphyton communities after isoproturon exposure for 14 and 26 days, respectively. Results showed good correlation of the PAM fluorescence-based measurements with traditional methods for biofilms in the initial colonisation phase for structural and functional parameters. However, for biofilms older than 9 weeks PAM fluorescence may underestimate biomass. Multiwavelength-excitation PAM fluorometry showed good correlation with marker pigment concentrations indicating that this method provides a reliable estimate of the community structure. PAM fluorometry was able to quantify changes of biomass and follow relative shifts in class composition of biofilms under exposure of isoproturon. Short-term tests based on the quantification of the inhibition of the effective quantum yield revealed a concentration-dependent increase of PICT. The observation of two succession phases of the biofilms after 14 and 26 days of growth, respectively, revealed that sensitivity of biofilms decreased with increasing age and biomass, respectively, but PICT remained a characteristic parameter of exposed

The influence of land use on water quality and diatom community ...

African Journals Online (AJOL)

Epilithic diatom communities offer a holistic and integrated approach for assessing water quality as they remain in one place for a number of months and reflect an ecological memory of water quality over a period of time. The objective of this study is to use diatom assemblages to distinguish between particular land types ...

Microbial Biofilm Community Variation in Flowing Habitats: Potential Utility as Bioindicators of Postmortem Submersion Intervals

Directory of Open Access Journals (Sweden)

Jennifer M. Lang

2016-01-01

Full Text Available Biofilms are a ubiquitous formation of microbial communities found on surfaces in aqueous environments. These structures have been investigated as biomonitoring indicators for stream heath, and here were used for the potential use in forensic sciences. Biofilm successional development has been proposed as a method to determine the postmortem submersion interval (PMSI of remains because there are no standard methods for estimating the PMSI and biofilms are ubiquitous in aquatic habitats. We sought to compare the development of epinecrotic (biofilms on Sus scrofa domesticus carcasses and epilithic (biofilms on unglazed ceramic tiles communities in two small streams using bacterial automated ribosomal intergenic spacer analysis. Epinecrotic communities were significantly different from epilithic communities even though environmental factors associated with each stream location also had a significant influence on biofilm structure. All communities at both locations exhibited significant succession suggesting that changing communities throughout time is a general characteristic of stream biofilm communities. The implications resulting from this work are that epinecrotic communities have distinctive shifts at the first and second weeks, and therefore the potential to be used in forensic applications by associating successional changes with submersion time to estimate a PMSI. The influence of environmental factors, however, indicates the lack of a successional pattern with the same organisms and a focus on functional diversity may be more applicable in a forensic context.

Periphyton changes over 20 years of chemical recovery of Lake Orta, Italy: differential response to perturbation of littoral and pelagic communities

OpenAIRE

Giuseppe MORABITO; Gabriele TARTARI; Rosario MOSELLO; Michèle DE SÈVE; Antonella CATTANEO

2011-01-01

Lake Orta, a large Italian subalpine lake, has a long history of industrial pollution by acid, ammonia, and metals. A whole-lake liming treatment in 1989-1990 led to a gradual increase in pH (from 4.4 to 7) and a concomitant decline in ammonia (from 2.5 to 0.05 mg L-1) and metal concentrations (e.g., copper: from 35 to 3 μg L-1). In this study, we examine the response of the littoral zone, in terms of chemistry and periphyton assemblages, to contamination and recovery of Lake Orta. We co...

Substratum as a driver of variation in periphyton chlorophyll and productivity in lakes

DEFF Research Database (Denmark)

Vadeboncoeur, Y.; Kalff, J.; Christoffersen, Kirsten Seestern

2006-01-01

content of periphyton on hard substrata (rocks and wood) was positively related to water-column total P (TP), whereas chlorophyll content of algae on sediment (epipelon) and TP were not significantly related. Chlorophyll content was up to 100× higher on sediments than on hard substrata. Within regions...... of the littoral zones in nutrient and energy cycles in lakes....

Effects of C/N controlled periphyton based organic farming of freshwater prawn on water quality parameters and biotic factors

Directory of Open Access Journals (Sweden)

Md. Rezoanul Haque

2014-08-01

Full Text Available The effects of C:N controlled periphyton based organic farming of freshwater prawn on water quality parameters and biotic factors were investigated. The experiment had two treatments: T1 and T2 each with three replications. Stocking density was maintained at 20,000 juveniles ha-1. In T1, only commercially available prawn feed was applied and in T2, a locally formulated and prepared feed containing 24% crude protein with C:N ratio close to 20 was used, and maize flour and bamboo side shoots were provided for maintaining C:N ratio 20.Mean values of water quality parameters did not vary significantly (P>0.05 between treatments. Periphytic biomass in terms of dry matter, ash free dry matter (AFDM and chlorophyll a showed significant difference (P<0.05 among different sampling months. Individual harvesting weight, individual weight gain, specific growth rates, gross and net yields of prawn were significantly higher (P<0.05 in T2 than T1. Therefore, it was concluded that freshwater prawn might consume periphyton biomass in C:N controlled periphyton based organic farming practices resulted a significantly (P<0.05 higher production of freshwater prawn than traditional farming.

Effects of bromacil, diuron, glyphosate, and sulfometuron-methyl on periphyton assemblages and rainbow trout : final report.

Science.gov (United States)

2003-01-01

This study documents the testing of several common herbicides used by the Oregon Department of Transportation in vegetation management. The project assessed the short- and long-term effects of Roundup, Krovar and Oust on periphyton and rainbow trout....

Combined effects of road salt and an insecticide on wetland communities.

Science.gov (United States)

Stoler, Aaron B; Walker, Brent M; Hintz, William D; Jones, Devin K; Lind, Lovisa; Mattes, Brian M; Schuler, Matthew S; Relyea, Rick A

2017-03-01

As the numbers of chemical contaminants in freshwater ecosystems increase, it is important to understand whether contaminants interact in ecologically important ways. The present study investigated the independent and interactive effects of 2 contaminants that frequently co-occur in freshwater environments among higher latitudes, including a commonly applied insecticide (carbaryl) and road salt (NaCl). The hypothesis was that the addition of either contaminant would result in a decline in zooplankton, an algal bloom, and the subsequent decline of both periphyton and periphyton consumers. Another hypothesis was that combining the contaminants would result in synergistic effects on community responses. Outdoor mesocosms were used with communities that included phytoplankton, periphyton, zooplankton, amphipods, clams, snails, and tadpoles. Communities were exposed to 4 environmentally relevant concentrations of salt (27 mg Cl - L -1 , 77 mg Cl - L -1 , 277 mg Cl - L -1 , and 727 mg Cl - L -1 ) fully crossed with 4 carbaryl treatments (ethanol, 0 µg L -1 , 5 µg L -1 , and 50 µg L -1 ) over 57 d. Contaminants induced declines in rotifer and cladoceran zooplankton, but only carbaryl induced an algal bloom. Consumers exhibited both positive and negative responses to contaminants, which were likely the result of both indirect community interactions and direct toxicity. In contrast to the hypothesis, no synergistic effects were found, although copepod densities declined when high concentrations of both chemicals were combined. The results suggest that low concentrations of salt and carbaryl are likely to have mostly independent effects on aquatic communities. Environ Toxicol Chem 2017;36:771-779. © 2016 SETAC. © 2016 SETAC.

Morphology and ultrastructure of epilithic versus cryptic, microbial growth in lower Cambrian phosphorites from the Montagne Noire, France.

Science.gov (United States)

Alvaro, J J; Clausen, S

2010-03-01

The lower Cambrian grainy phosphorites of the northern Montagne Noire occur interbedded with grey to black, laminated to massive shales and limestones deposited along the edge of a continental shelf, associated with slope-related facies and unstable substrates. The concentration of phosphate took place by repeated alternations of low sedimentation rates and condensation (hardgrounds), in situ early-diagenetic precipitation of fluorapatite, winnowing and polyphase reworking of previously phosphatized skeletons and hardground-derived clasts. The succession of repeated cycles of sedimentation, phosphate concentration, and reworking led to multi-event phosphate deposits rich in allochthonous particles. Phosphogenesis was primarily mediated by microbial activity, which is evidenced by the abundance of phosphatized putative microbial remains. These occur as smooth and segmented filaments, sheaths, and ovoid-shaped coccoids. These simple morphologies commonly form composite frameworks as a result of their aggregation and entanglement, leading to the record of biofilms, microbial mats, and complex networks. These infested the calcitic skeletonized microfossils that littered the substrate. Microbial activity evidences epilithic (anisotropic coatings on skeletons), euendolithic (perforating skeletal walls), and cryptoendolithic (lining inter- and intraparticulate pores) strategies, the latter dominated by bundles of filaments and globular clusters that grew along the cavities of helcionellids and hyoliths. According to their epilithic versus cryptic strategies, microbial populations that penetrated and dwelled inside hard skeletal substrates show different network and colonial morphologies. These early Cambrian shell concentrations were the loci of a stepwise colonization made by saprophytic to mutualistic, cyanobacterial-fungal consortia. Their euendolithic and cryptoendolithic ecological niches provided microbial refugia to manage the grazing impact mainly led by metazoans.

The use of indices for evaluating the periphytic community in two kinds of substrate in Imboassica Lagoon, Rio de Janeiro, Brazil

Directory of Open Access Journals (Sweden)

Fernandes V. O.

2003-01-01

Full Text Available Biological indices based on the biomass (dry weight, ash content, and chlorophyll-a of the periphyton in a natural (submersed leaves of Typha domingensis Pers and in an artificial (plastic hoses substrate were compared, in experiments performed in summer and winter, in two sampling stations of Imboassica Lagoon, Macaé, Rio de Janeiro. The periphytic community exhibited low biomass at the beginning and end of the experiments, and moderate biomass in the intermediate period of the experiment, whatever the kind of substrate, sampling station, and season. In both seasons, there was a spatial variation regarding the degree of trophy of the periphyton, due to the difference of nutrient availability among the sampling stations. The alternation of inorganic and organic periphyton, as well as of their heterotrophic, hetero-autotrophic, auto-heterotrophic and, autotrophic character was due to changes in the abiotic factors of the sampling periods. The Lakatos index proved more sensitive than the Autotrophic Index to variations in the composition of the periphytic community.

Atmospheric transport of urban-derived NHx: Evidence from nitrogen concentration and δ15N in epilithic mosses at Guiyang, SW China

International Nuclear Information System (INIS)

Liu Xueyan; Xiao Huayun; Liu Congqiang; Li Youyi; Xiao Hongwei

2008-01-01

Nitrogen concentration and δ 15 N in 175 epilithic moss samples were investigated along four directions from urban to rural sites in Guiyang, SW China. The spatial variations of moss N concentration and δ 15 N revealed that atmospheric N deposition is dominated by NH x -N from two major sources (urban sewage NH 3 and agricultural NH 3 ), the deposition of urban-derived NH x followed a point source pattern characterized by an exponential decline with distance from the urban center, while the agricultural-derived NH x was shown to be a non-point source. The relationship between moss N concentration and distance (y = 1.5e -0.13x + 1.26) indicated that the maximum transporting distance of urban-derived NH x averaged 41 km from the urban center, and it could be determined from the relationship between moss δ 15 N and distance [y = 2.54 ln(x) - 12.227] that urban-derived NH x was proportionally lower than agricultural-derived NH x in N deposition at sites beyond 17.2 km from the urban center. Consequently, the variation of urban-derived NH x with distance from the urban center could be modeled as y = 56.272e -0.116x - 0.481 in the Guiyang area. - Tissue N concentration and δ 15 N in epilithic mosses may be indicators for atmospheric transport of urban-derived NH x

C/N-controlled periphyton-based freshwater prawn farming system: a sustainable approach to increase pond productivity

NARCIS (Netherlands)

Asaduzzaman, M.

2012-01-01

Three technologies showed to improve productivity and sustainability of pond production: (1) C/N ratio control, (2) providing substrates for periphyton development, and (3) fish driven re-suspension. The novelty of this PhD research is to combine these technologies, with the goal to raise pond

Macrophytes and periphyton carbon subsidies to bacterioplankton and zooplankton in a shallow eutrophic lake in tropical China

NARCIS (Netherlands)

de Kluijver, A.; Ning, J.; Liu, Z.; Jeppesen, E.; Gulati, R.D.; Middelburg, J.J.

The subsidy of carbon derived from macrophytes and associated periphyton to bacterioplankton and zooplankton in subtropical shallow eutrophic Huizhou West Lake in China was analyzed using carbon stable isotope signatures. A restored part of the lake dominated by macrophytes was compared with an

Macrophytes and periphyton carbon subsidies to bacterioplankton and zooplankton in a shallow eutrophic lake in tropical China

NARCIS (Netherlands)

de Kluijver, A.; Ning, J.; Liu, Z.; Jeppesen, E.; Gulati, R.D.; Middelburg, J.J.

2015-01-01

The subsidy of carbon derived from macrophytes and associated periphyton to bacterioplankton and zooplankton in subtropical shallow eutrophic Huizhou West Lake in China was analyzed using carbon stable isotope signatures. A restored part of the lake dominated by macrophytes was compared with an

Mercury and flooding cycles in the Tapajos river basin, Brazilian Amazon: The role of periphyton of a floating macrophyte (Paspalum repens)

International Nuclear Information System (INIS)

Coelho-Souza, Sergio A.; Guimaraes, Jean R.D.; Miranda, Marcio R.; Poirier, Hugo; Mauro, Jane B.N.; Lucotte, Marc; Mergler, Donna

2011-01-01

Methylmercury (MeHg) increases mercury (Hg) toxicity and is biomagnified in the trophic chain contaminating riverine Amazon populations. Freshwater macrophyte roots are a main site of Hg methylation in different Brazilian environments. Paspalum repens periphyton was sampled in four floodplain lakes during the dry, rainy and wet seasons for measurement of total Hg (THg), MeHg, Hg methylation potentials, %C, %N, δ 13 C, δ 15 N and bacterial heterotrophic production as 3 H-leucine incorporation rate. THg concentration varied from 67 to 198 ng/g and the potential of Me 203 Hg formation was expressive (1-23%) showing that periphyton is an important matrix both in the accumulation of Hg and in MeHg production. The concentration of MeHg varied from 1 to 6 ng/g DW and was positively correlated with Me 203 Hg formation. Though methylmercury formation is mainly a bacterial process, no significant correlation was observed between the methylation potentials and bacterial production. The multiple regressions analyses suggested a negative correlation between THg and %C and %N and between methylation potential and δ 13 C. The discriminant analysis showed a significant difference in periphyton δ 15 N, δ 13 C and THg between seasons, where the rainy season presented higher δ 15 N and the wet period lighter δ 13 C, lower THg values and higher Me 203 Hg formation. This exploratory study indicates that the flooding cycle could influence the periphyton composition, mercury accumulation and methylmercury production. - Research highlights: → During rainy season mercury (Hg 2+ ) is carried out from terrestrial to aquatic systems by runoff. → Macrophyte roots accumulates Hg 2+ from suspended particulate matter (SPM). → Hg methylation increases during the wet season. → Flooded forest is a source of labile organic carbon and bioavailable Hg. → Macrophytes decompose during the dry season and made up terrestrial soil.

Microbial community composition and endolith colonization at an Arctic thermal spring are driven by calcite precipitation

Science.gov (United States)

Starke, Verena; Kirshtein, Julie; Fogel, Marilyn L.; Steele, Andrew

2013-01-01

Environmental conditions shape community composition. Arctic thermal springs provide an opportunity to study how environmental gradients can impose strong selective pressures on microbial communities and provide a continuum of niche opportunities. We use microscopic and molecular methods to conduct a survey of microbial community composition at Troll Springs on Svalbard, Norway, in the high Arctic. Microorganisms there exist under a wide range of environmental conditions: in warm water as periphyton, in moist granular materials, and in cold, dry rock as endoliths. Troll Springs has two distinct ecosystems, aquatic and terrestrial, together in close proximity, with different underlying environmental factors shaping each microbial community. Periphyton are entrapped during precipitation of calcium carbonate from the spring's waters, providing microbial populations that serve as precursors for the development of endolithic communities. This process differs from most endolith colonization, in which the rock predates the communities that colonize it. Community composition is modulated as environmental conditions change within the springs. At Troll, the aquatic environments show a small number of dominant operational taxonomic units (OTUs) that are specific to each sample. The terrestrial environments show a more even distribution of OTUs common to multiple samples.

Impact of pumped-storage hydropower plant PVE Cierny Vah on transport of particulate organic matter and periphyton biomass

International Nuclear Information System (INIS)

Bokorova, L.; Kokavec, I.

2015-01-01

Although the Serial Discontinuity Concept (SDC) is supported by the results of scientific research, there are specific cases where changes in certain factors get opposite values. The aim of this work was to evaluate the effect of PVE Cierny Vah on POM and periphyton biomass. Below the PVE Cierny Vah was found more than 5- fold increase in periphyton biomass compared to the site above the dam, which was also reflected in the amount of BOM. Reservoir acts as a sediment trap, but PVE Cierny Vah on average captures nearly 30% of TOM. Therefore sedimentation takes place below the dam as well as above. The decrease in the POM ratio dowstream of the PVE Cierny Vah confirms the SDC hypothesis about the impact of the dam in the headwaters. Each reservoir is somewhat unique, and therefore, it is necessary to consider all factors potenti (authors)

Complex and interactive effects of ocean acidification and temperature on epilithic and endolithic coral-reef turf algal assemblages

Science.gov (United States)

Johnson, Maggie D.; Comeau, Steeve; Lantz, Coulson A.; Smith, Jennifer E.

2017-12-01

Turf algal assemblages are ubiquitous primary producers on coral reefs, but little is known about the response of this diverse group to ocean acidification (OA) across different temperatures. We tested the hypothesis that CO2 influences the functional response of epilithic and endolithic turf assemblages to increasing temperature. Replicate carbonate plugs covered by turf were collected from the reef and exposed to ambient and high pCO2 (1000 µatm) conditions for 3 weeks. Each pCO2 treatment was replicated across six temperatures (24.0-31.5 °C) that spanned the full seasonal temperature range on a fringing reef in Moorea, French Polynesia, and included one warming treatment (3 °C above daily average temperatures). Temperature and CO2 enrichment had complex, and sometimes interactive, effects on turf metabolism and growth. Photosynthetic and respiration rates were enhanced by increasing temperature, with an interactive effect of CO2 enrichment. Photosynthetic rates were amplified by high CO2 in the warmest temperatures, while the increase in respiration rates with temperature were enhanced under ambient CO2. Epilithic turf growth rates were not affected by temperature, but increased in response to CO2 enrichment. We found that CO2 and temperature interactively affected the endolithic assemblage, with the highest growth rates under CO2 enrichment, but only at the warmest temperatures. These results demonstrate how OA may influence algal physiology and growth across a range of ecologically relevant temperatures, and indicate that the effects of CO2 enrichment on coral-reef turf assemblages can be temperature dependent. The complex effects of CO2 enrichment and temperature across a suite of algal responses illustrates the importance of incorporating multiple stressors into global change experiments.

Impacts of agricultural irrigation on nearby freshwater ecosystems: the seasonal influence of triazine herbicides in benthic algal communities.

Science.gov (United States)

Lorente, Carmen; Causapé, Jesús; Glud, Ronnie N; Hancke, Kasper; Merchán, Daniel; Muñiz, Selene; Val, Jonatan; Navarro, Enrique

2015-01-15

A small hydrological basin (Lerma, NE Spain), transformed from its natural state (steppe) to rain-fed agriculture and recently to irrigation agriculture, has been monitored across four seasons of an agricultural year. The goal of this study was to assess how and whether agricultural activities impacted the nearby freshwater ecosystems via runoff. Specifically, we assessed the toxicity of three triazine herbicides, terbuthylazine, atrazine and simazine on the photosynthetic efficiency and structure of algal benthic biofilms (i.e., phototropic periphyton) in the small creek draining the basin. It was expected that the seasonal runoff of the herbicides in the creek affected the sensitivity of the periphyton in accord with the rationale of the Pollution Induced Community Tolerance (PICT): the exposure of the community to pollutants result in the replacement of sensitive species by more tolerant ones. In this way, PICT can serve to establish causal linkages between pollutants and the observed biological impacts. The periphyton presented significantly different sensitivities against terbuthylazine through the year in accord with the seasonal application of this herbicide in the crops nowadays. The sensitivity of already banned herbicides, atrazine and simazine does not display a clear seasonality. The different sensitivities to herbicides were in agreement with the expected exposures scenarios, according to the agricultural calendar, but not with the concentrations measured in water, which altogether indicates that the use of PICT approach may serve for long-term monitoring purposes. That will provide not only causal links between the occurrence of chemicals and their impacts on natural communities, but also information about the occurrence of chemicals that may escape from traditional sampling methods (water analysis). In addition, the EC50 and EC10 of periphyton for terbuthylazine or simazine are the first to be published and can be used for impact assessments

Influence of periphyton substrates and rearing density on Liza aurata growth and production in marine nursery ponds

NARCIS (Netherlands)

Richard, M.; Maurice, J.T.; Anginot, A.; Paticat, F.; Verdegem, M.C.J.; Hussenot, J.M.E.

2010-01-01

The main objectives of this investigation were to test the effects of (i) the presence of periphyton substrates, (ii) rearing density and (iii) supplemental feeding with dry feed on the growth and production of golden mullet (Liza aurata) juveniles. Twenty-six 1 m2-cages were installed in a French

[Changes in phytoperiphyton community during seasonal succession: influence of plankton sedimentation and grazing by phytophages--Chironomid larvae].

Science.gov (United States)

Lukin, V B

2002-01-01

The investigation of seasonal changes in spatial structure of phytoperiphyton during succession was conducted at the lower reaches of Akulovsky water channel from April to August 2000. At the beginning of succession from April to June dominant forms were chain-forming diatoms and filamentous green algae, sedimented from plankton. Later, at the middle of June under increasing pressure of herbivorous, they were replaced by stretched unicellular diatoms and colonial cyanobacteria. In late June-August, when herbivorous predation was the most intensive, the relative abundance of typical periphytonic forms decreased while that of settled planktonic forms increased. The effect of planktonic algae sedimentation on periphyton composition was evaluated as similarity between phytoperiphyton and phytoplankton communities measured with Chekanovski--Sorensen index. The value of this index tends to decrease with the development of periphyton while showing some relation to intensity of herbivorous pressure. Minimal values of Chekanovski--Sorensen index were under moderate herbivorous density, whereas maximal values were observed in periods of extremely high or low herbivorous density.

Mercury and flooding cycles in the Tapajos river basin, Brazilian Amazon: The role of periphyton of a floating macrophyte (Paspalum repens)

Energy Technology Data Exchange (ETDEWEB)

Coelho-Souza, Sergio A., E-mail: sacs@biof.ufrj.br [Lab. Tracadores Wolfgang C. Pfeiffer, SL 049, Instituto de Biofisica Carlos Chagas Filho/UFRJ, Bloco G, Centro de Ciencias e Saude, Ilha do Fundao, Rio de Janeiro, RJ, CEP 21949-902 (Brazil); Guimaraes, Jean R.D.; Miranda, Marcio R. [Lab. Tracadores Wolfgang C. Pfeiffer, SL 049, Instituto de Biofisica Carlos Chagas Filho/UFRJ, Bloco G, Centro de Ciencias e Saude, Ilha do Fundao, Rio de Janeiro, RJ, CEP 21949-902 (Brazil); Poirier, Hugo [Chaire de Reserche en Environment, Universite du Quebec a Montreal (UQaM), CP 8888, Montreal, H3C 3P8 (Canada); Mauro, Jane B.N. [Lab. Tracadores Wolfgang C. Pfeiffer, SL 049, Instituto de Biofisica Carlos Chagas Filho/UFRJ, Bloco G, Centro de Ciencias e Saude, Ilha do Fundao, Rio de Janeiro, RJ, CEP 21949-902 (Brazil); Lucotte, Marc [Chaire de Reserche en Environment, Universite du Quebec a Montreal (UQaM), CP 8888, Montreal, H3C 3P8 (Canada); Mergler, Donna [CINBIOSE, UQaM, CP 8888, succ. Centre-ville, Montreal, H3C 3P8 (Canada)

2011-06-15

Methylmercury (MeHg) increases mercury (Hg) toxicity and is biomagnified in the trophic chain contaminating riverine Amazon populations. Freshwater macrophyte roots are a main site of Hg methylation in different Brazilian environments. Paspalum repens periphyton was sampled in four floodplain lakes during the dry, rainy and wet seasons for measurement of total Hg (THg), MeHg, Hg methylation potentials, %C, %N, {delta}{sup 13}C, {delta}{sup 15}N and bacterial heterotrophic production as {sup 3}H-leucine incorporation rate. THg concentration varied from 67 to 198 ng/g and the potential of Me{sup 203}Hg formation was expressive (1-23%) showing that periphyton is an important matrix both in the accumulation of Hg and in MeHg production. The concentration of MeHg varied from 1 to 6 ng/g DW and was positively correlated with Me{sup 203}Hg formation. Though methylmercury formation is mainly a bacterial process, no significant correlation was observed between the methylation potentials and bacterial production. The multiple regressions analyses suggested a negative correlation between THg and %C and %N and between methylation potential and {delta}{sup 13}C. The discriminant analysis showed a significant difference in periphyton {delta}{sup 15}N, {delta}{sup 13}C and THg between seasons, where the rainy season presented higher {delta}{sup 15}N and the wet period lighter {delta}{sup 13}C, lower THg values and higher Me{sup 203}Hg formation. This exploratory study indicates that the flooding cycle could influence the periphyton composition, mercury accumulation and methylmercury production. - Research highlights: {yields} During rainy season mercury (Hg{sup 2+}) is carried out from terrestrial to aquatic systems by runoff. {yields} Macrophyte roots accumulates Hg{sup 2+} from suspended particulate matter (SPM). {yields} Hg methylation increases during the wet season. {yields} Flooded forest is a source of labile organic carbon and bioavailable Hg. {yields} Macrophytes

Stable nitrogen isotope ratios of macrophytes and associated periphyton along a nitrate gradient in two subtropical, spring-fed streams

DEFF Research Database (Denmark)

De Brabandere, Loreto; Frazer, Thomas K.; Montoya, Joseph P.

2007-01-01

, macrophytes and periphyton as a consequence of isotopic fractionation associated with preferential use of 14NO3-. This hypothesis was tested in two spring-fed river systems, the Chassahowitzka and Homosassa rivers, along Florida’s central Gulf of Mexico coast. 3. In general, d15N values of nitrate...

Incidence of invasive macrophytes on methylmercury budget in temperate lakes: Central role of bacterial periphytic communities

International Nuclear Information System (INIS)

Gentès, Sophie; Monperrus, Mathilde; Legeay, Alexia; Maury-Brachet, Régine; Davail, Stephane; André, Jean-Marc; Guyoneaud, Rémy

2013-01-01

Several studies demonstrated high mercury (Hg) methylation and demethylation in the periphyton associated with floating roots in tropical ecosystems. The importance of aquatic plants on methylmercury production in three temperate ecosystems from south-western France was evaluated through Hg species concentrations, and Hg methylation/demethylation activities by using stable isotopic tracers ( 199 Hg(II), Me 201 Hg). Hg accumulation and high methylation and demethylation yields were detected in plant roots and periphyton, whereas results for sediment and water were low to insignificant. The presence of sulfate reducing prokaryotes was detected in all compartments (T-RFLP based on dsrAB amplified through nested PCR) and their main role in Hg methylation could be demonstrated. In turn, sulfate reduction inhibition did not affect demethylation activities. The estimation of net MeHg budgets in these ecosystems suggested that aquatic rhizosphere is the principal location for methylmercury production and may represent an important source for the contamination of the aquatic food chain. - Highlights: ► Both Hg methylation and demethylation occur in the periphyton of temperate ecosystems. ► Aquatic rhizosphere is the main compartment for net methylmercury production. ► Sulfate reducers are detected in all ecosystem compartments (water, sediment, periphyton). ► Sulfate reducers are responsible for methylmercury production in aquatic roots. - The incidence of periphytic microbial communities on net methylmercury production is highlighted in temperate aquatic ecosystems.

Spatial Patterns in Biofilm Diversity across Hierarchical Levels of River-Floodplain Landscapes.

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Marc Peipoch

Full Text Available River-floodplain systems are among the most diverse and productive ecosystems, but the effects of biophysical complexity at multiple scales on microbial biodiversity have not been studied. Here, we investigated how the hierarchical organization of river systems (i.e., region, floodplain, zone, habitats, and microhabitats influences epilithic biofilm community assemblage patterns by characterizing microbial communities using 16S rRNA gene sequence data and analyzing bacterial species distribution across local and regional scales. Results indicate that regional and local environmental filters concurrently sort bacterial species, suggesting that spatial configuration of epilithic biofilms resembles patterns of larger organisms in floodplain ecosystems. Along the hierarchical organization of fluvial systems, floodplains constitute a vector of maximum environmental heterogeneity and consequently act as a major landscape filter for biofilm species. Thus, river basins and associated floodplains may simply reflect very large scale 'patches' within which environmental conditions select for community composition of epilithic biofilms.

A mine of information: Benthic algal communities as biomonitors of metal contamination from abandoned tailings

International Nuclear Information System (INIS)

Lavoie, Isabelle; Lavoie, Michel; Fortin, Claude

2012-01-01

Various biomonitoring approaches were tested in the field to assess the response of natural periphythic algal communities to chronic metal contamination downstream from an abandoned mine tailings site. The accumulation of cadmium (Cd), copper (Cu), lead (Pb) and zinc (Zn) as well as the production of phytochelatins, the presence of diatom taxa known to tolerate high metal concentrations, diatom diversity and the presence of teratologies were determined. We observed highly significant relationships between intracellular metal and calculated free metal ion concentrations. Such relationships are often observed in laboratory studies but have been rarely validated in field studies. These results suggest that the concentration of metal inside the field-collected periphyton, regardless of its species composition, is a good indicator of exposure and is an interesting proxy for bioavailable metal concentrations in natural waters. The presence of teratologies and metal-tolerant taxa at our contaminated sites provided a clear indication that diatom communities were responding to this metal stress. A multi-metric approach integrating various bioassessment methods could be used for the field monitoring of metal contamination and the quantification of its effects. Highlights: ► Various approaches for metal contamination biomonitoring were used in the field. ► Metal accumulation in periphyton is correlated to free ion concentration. ► Teratologies and metal-tolerant taxa provided a clear indication of metal stress. ► Stream periphyton shows great potential as a biomonitor of metal contamination.

Different Heavy Metal Accumulation Strategies of Epilithic Lichens Colonising Artificial Post-Smelting Wastes.

Science.gov (United States)

Rola, Kaja; Osyczka, Piotr; Kafel, Alina

2016-02-01

Lichens appear to be essential and effective colonisers of bare substrates including the extremely contaminated wastes of slag dumps. This study examines the metal accumulation capacity of epilithic lichens growing directly on the surface of artificial slag sinters. Four species representing different growth forms, i.e., crustose Candelariella aurella, Lecanora muralis, and Lecidea fuscoatra and fruticose Stereocaulon nanodes, were selected to evaluate the relationships between zinc, lead, cadmium, and nickel contents in their thalli and host substrates. Bioaccumulation factors of examined crustose lichens showed their propensity to hyperaccumulate heavy metals. Contrarily, concentrations of metals in fruticose thalli of S. nanodes were, as a rule, lower than in the corresponding substrates. This indicates that the growth form of thalli and degree of thallus adhesion to the substrate has a significant impact on metal concentrations in lichens colonising post-smelting wastes. Nonlinear regression models described by power functions show that at greater levels of Pb concentration in the substrate, the ability of C. aurella, L. muralis and L. fuscoatra to accumulate the metal experiences a relative decrease, whereas hyperbolic function describes a similar trend in relation to Ni content in S. nanodes. This phenomenon may be an important attribute of lichens that facilitates their colonisation of the surface of slag wastes.

Technical evaluation of tilapia (Oreochromis niloticus) monoculture and tilapia-prawn (Macrobrachium rosenbergii) polyculture in earthen ponds with or without substrates for periphyton development

NARCIS (Netherlands)

Uddin, S.; Farzana, A.; Fatema, M.K.; Azim, M.E.; Wahab, M.A.; Verdegem, M.C.J.

2007-01-01

The effects of periphyton grown on bamboo substrate, on growth and production of Nile tilapia, Oreochromis niloticus (Genetically Improved Farmed Tilapia strain) in monoculture and polyculture with the freshwater prawn (Macrobrachium rosenbergii) were studied and economically evaluated. The

Ecological responses of epilithic diatoms and aquatic macrophytes to fish farm pollution in a Spanish river

Directory of Open Access Journals (Sweden)

Camargo, Julio A.

2007-12-01

Full Text Available We examined the ecological responses of epilithic diatoms and aquatic macrophytes to organic pollution and nutrient enrichment caused by a trout farm effluent in the upper Tajuña River (Guadalajara, Spain. Four sampling sites were selected over the study area: one site (S-1 placed upstream from the trout farm was used as a reference station; sampling sites S-2, S-3 and S-4 were set, respectively, about 10, 100 and 1000 metres downriver of the trout farm outlet. The river bottom was mainly stony with cobbles and pebbles at S-1, S-3 and S-4, but at S-2 it was covered by a thick layer of organic sediment. Although some macrophyte species (Apium nodiflorum, Groenlandia densa were either absent or fewer downstream of the farm, abundance (% coverage and diversity (number of species for the aquatic macrophyte community as a whole increased. In contrast, epilithic diatoms were completely absent at S-2, and some species (Diploneis parma, Fragilaria ulna, Gomphonema angustatum, Nitzschia dissipata were also absent at S-3 and S-4. Indeed, diatom diversity (number of species was lower at S-3 and S-4 than at S-1. However, diatom abundance (cells/cm2 was higher at S-3 and S-4 than at S-1. Biological indices for diatoms (IBD, TDI indicated a better water quality at S-1 than at S-3 and S-4, with a clear tendency to improve with distance from the fish farm. In contrast, biological indices of macrophytes (IM, IVAMG indicated a similar water quality at S-1, S-3 and S-4, but with bad water quality at S-2. We conclude that epilithic diatoms may be more useful than aquatic macrophytes for biological monitoring of fish farm pollution in fluvial ecosystems. However, as historical and seasonal factors may be relevant to understanding the distribution, abundance and diversity of primary producers in running waters, further studies on long-term seasonal changes are needed to improve the use of macrophyte and diatom indices in assessing fish farm pollution.En este trabajo

Short-term responses to watershed logging on biomass mercury and methylmercury accumulation by periphyton in boreal lakes

Energy Technology Data Exchange (ETDEWEB)

Desrosiers, M.; Planas, D. [Quebec Univ., Montreal, PQ (Canada). Dept. de sciences biologiques; Mucci, A. [McGill Univ., Montreal, PQ (Canada). Dept. of Earth and Planetary Sciences

2006-08-15

Increased timber harvesting in the boreal regions of Quebec may have a significant impact on aquatic ecosystems. Watershed disturbances such as logging increase chemical loading to lakes. Soil in the Canadian Shield readily adsorbs and accumulates mercury (Hg) from atmospheric deposition. Forest watersheds serve as large reservoirs of Hg that shed their metal load when soil and land hydrology are disrupted. This paper presented the results of a study evaluating the impact of logging on periphyton algal biomass and dry mass. The study also evaluated the impact of total mercury (THG) and methylmercury (MeHg) accumulation in the littoral zone of the boreal lakes. A before-after control-impact (BACI) sample design was applied that required data from control and target sites sampled both before and after the disturbances. The study was carried out on 18 boreal lakes located in the Grenville geological province. Eight lakes had their watersheds logged over 15 to 79 per cent of their area. A further 10 lakes were used as control sites to document interannual variations. The project used water quality and physiographic data acquired by research groups within the Sustainable Forest Management Network. Fourteen study lakes were sampled once a year during 2 consecutive ice-free seasons before and after logging, and another 4 lakes were sampled 2 years after logging. Significant decreases in algal biomass and increases in MeHg concentrations in periphyton mats in a majority of the harvested watershed lakes were detected. The increases may have a significant impact on organisms of higher trophic levels as they are at the base of the food web. Results suggested that the observed decrease in periphyton biomass combined with the increase in MeHg accumulation may magnify the impact of logging activities on fish and other aquatic predators. Two years after logging, it was observed that MeHg concentrations were still increasing. It was concluded that further research is needed

The potential of mixed culture of genetically improved farmed tilapia (GIFT, Oreochromis niloticus) and freshwater giant prawn (Macrobrachium rosenbergii) in periphyton-based systems

NARCIS (Netherlands)

Uddin, S.; Azim, M.E.; Wahab, M.A.; Verdegem, M.C.J.

2006-01-01

The production performance of genetically improved farmed tilapia (GIFT, Oreochromis niloticus) and freshwater prawn (Macrobrachium rosenbergii) in periphyton-based systems were studied in farmers' ponds at Mymensingh, Bangladesh. Fifteen ponds (200-300 m2 area and 1.0-1.5 m in depth) were used to

New evidences of Roundup (glyphosate formulation) impact on the periphyton community and the water quality of freshwater ecosystems.

Science.gov (United States)

Vera, María S; Lagomarsino, Leonardo; Sylvester, Matías; Pérez, Gonzalo L; Rodríguez, Patricia; Mugni, Hernán; Sinistro, Rodrigo; Ferraro, Marcela; Bonetto, Carlos; Zagarese, Horacio; Pizarro, Haydée

2010-04-01

Argentina is the second largest world producer of soybeans (after the USA) and along with the increase in planted surface and production in the country, glyphosate consumption has grown in the same way. We investigated the effects of Roundup (glyphosate formulation) on the periphyton colonization. The experiment was carried out over 42 days in ten outdoor mesocosms of different typology: "clear" waters with aquatic macrophytes and/or metaphyton and "turbid" waters with great occurrence of phytoplankton or suspended inorganic matter. The herbicide was added at 8 mg L(-1) of the active ingredient (glyphosate) in five mesocosms while five were left as controls (without Roundup addition). The estimate of the dissipation rate (k) of glyphosate showed a half-life value of 4.2 days. Total phosphorus significantly increased in treated mesocosms due to Roundup degradation what favored eutrophication process. Roundup produced a clear delay in periphytic colonization in treated mesocosms and values of the periphytic mass variables (dry weight, ash-free dry weight and chlorophyll a) were always higher in control mesocosms. Despite the mortality of algae, mainly diatoms, cyanobacteria was favored in treated mesocosms. It was observed that glyphosate produced a long term shift in the typology of mesocosms, "clear" turning to "turbid", which is consistent with the regional trend in shallow lakes in the Pampa plain of Argentina. Based on our findings it is clear that agricultural practices that involve the use of herbicides such as Roundup affect non-target organisms and the water quality, modifying the structure and functionality of freshwater ecosystems.

Assessment of water quality, benthic invertebrates, and periphyton in the Threemile Creek basin, Mobile, Alabama, 1999-2003

Science.gov (United States)

McPherson, Ann K.; Gill, Amy C.; Moreland, Richard S.

2005-01-01

The U.S. Geological Survey conducted a 4-year investigation of water quality and aquatic-community structure in Threemile Creek, an urban stream that drains residential areas in Mobile, Alabama. Water-quality samples were collected between March 2000 and September 2003 at four sites on Threemile Creek, and between March 2000 and October 2001 at two tributary sites that drain heavily urbanized areas in the watershed. Stream samples were analyzed for major ions, nutrients, fecal-indicator bacteria, and selected organic wastewater compounds. Continuous measurements of dissolved-oxygen concentrations, water temperature, specific conductance, and turbidity were recorded at three sites on Threemile Creek during 1999?2003. Aquatic-community structure was evaluated by conducting one survey of the benthic invertebrate community and multiple surveys of the algal community (periphyton). Benthic invertebrate samples were collected in July 2000 at four sites on Threemile Creek; periphyton samples were collected at four sites on Threemile Creek and the two tributary sites during 2000 ?2003. The occurrence and distribution of chemical constituents in the water column provided an initial assessment of water quality in the streams; the structure of the benthic invertebrate and algal communities provided an indication of the cumulative effects of water quality on the aquatic biota. Information contained in this report can be used by planners and resource managers in the evaluation of proposed total maximum daily loads and other restoration efforts that may be implemented on Threemile Creek. The three most upstream sites on Threemile Creek had similar water chemistry, characterized by a strong calcium-bicarbonate component; the most downstream site on Threemile Creek was affected by tidal fluctuations and mixing from Mobile Bay and had a strong sodium-chloride component. The water chemistry at the tributary site on Center Street was characterized by a strong sodium-chloride component

Influence of global change-related impacts on the mercury toxicity of freshwater algal communities.

Science.gov (United States)

Val, Jonatan; Muñiz, Selene; Gomà, Joan; Navarro, Enrique

2016-01-01

The climatic-change related increase of temperatures, are expected to alter the distribution and survival of freshwater species, ecosystem functions, and also the effects of toxicants to aquatic biota. This study has thus assessed, as a first time, the modulating effect of climate-change drivers on the mercury (Hg) toxicity of freshwater algal photosynthesis. Natural benthic algal communities (periphyton) have been exposed to Hg under present and future temperature scenarios (rise of 5 °C). The modulating effect of other factors (also altered by global change), as the quality and amount of suspended and dissolved materials in the rivers, has been also assessed, exposing algae to Hg in natural river water or a synthetic medium. The EC50 values ranged from the 0.15-0.74 ppm for the most sensitive communities, to the 24-40 ppm for the most tolerant. The higher tolerance shown by communities exposed to higher Hg concentrations, as Jabarrella was in agreement with the Pollution Induced Community Tolerance concept. In other cases, the dominance of the invasive diatom Didymosphenia geminata explained the tolerance or sensitivity of the community to the Hg toxicity. Results shown that while increases in the suspended solids reduced Hg bioavailability, changes in the dissolved materials - such as organic carbon - may increase it and thus its toxic effects on biota. The impacts of the increase of temperatures on the toxicological behaviour of periphyton (combining both changes at species composition and physiological acclimation) would be certainly modulated by other effects at the land level (i.e., alterations in the amount and quality of dissolved and particulate substances arriving to the rivers). Copyright © 2015 Elsevier B.V. All rights reserved.

Biomass and relative coverage of benthic algae in the fore-reef of Curacao (Netherlands Antilles) in relation to production

Energy Technology Data Exchange (ETDEWEB)

de Ruyter van Stevenick, E.D.; Breeman, A.M.

1981-11-15

Biomass of benthic algae, expressed as chlorophyll a content (..mu..g cm/sup -2/) and as dry weight (mg cm/sup -2/) per substrate surface area in the coral reef of Curacao at 12 m and 25 m depth was measured from August 1978 to March 1979. To determine dry weights, substrates containing endolithic and epilithic algae were oxidized by means of wet combustion with hydrogen peroxide. Loss of weight caused by this process was regarded as algal dry weight. The crustose corallines Archaeolithothamnion dimotum Fosl. et Howe (25 m), Hydrolithon boergesenii (Fosl.) Fosl. (12 m and 25 m) and Lithophyllum cf. intermedium Fosl. (12 m), vegetations of endolithic algae dominated by Ostreobium quekettii Born. et Flah. (12 m and 25 m), and mixed turfs of epilithic filamentous algae and sometimes Lithophyllum cf. intermedium on substrates containing endolithic algae (12 m and 25 m) were examined. Chlorophyll a values ranged from 8.7 ..mu..g cm/sup -2/ for H. boergesenii at 12 m to 20.5 ..mu..g cm/sup -2/ for epilithic filamentous algae on substrates containing endolithic algae at 25 m. Dry weights varied from 12.7 mg cm/sup -2/ for L. cf. intermedium at 12 m to 25.7 mg cm/sup -2/ for epilithic filamentous algae on substrates containing endolithic algae at 25 m. Both at 12 m and 25 m, differences in chlorophyll a content and dry weights between substrates containing endolithic algae with and without epilithic filamentous algae were low. Biomass of endolithic algae is quantitatively more important than that of epilithic filamentous algae. It is concluded that, at 12 m, biomass of the algal vegetation as a whole is lowest while production is highest. This is attributed to maximum grazing pressure at this depth ('drop off' community), especially on epilithic filamentous algae.

Periphyton ecology of glacial and snowmelt streams, Ny-Alesund, Svalbard: presence of mineral particles in water and their erosive activity

Czech Academy of Sciences Publication Activity Database

Kubečková, Klára; Elster, Josef; Kanda, H.

2001-01-01

Roč. 123, - (2001), s. 141-172 ISSN 1438-9134. [International conference: Algae and extreme environments. Třeboň, 11.09.2000-16.09.2000] R&D Projects: GA AV ČR KSK6005114; GA AV ČR IAA6005002 Institutional research plan: CEZ:AV0Z6005908; CEZ:MSM 123100004 Keywords : Periphyton * species diversity and productivity * the Arctic * glacial snowmelt streams * physical disturbances erosive discharge * water turbidity Subject RIV: EA - Cell Biology Impact factor: 0.488, year: 2000

Submerged macrophytes mitigate direct and indirect insecticide effects in freshwater communities.

Science.gov (United States)

Brogan, William R; Relyea, Rick A

2015-01-01

Understanding how ecological interactions mitigate the impacts of perturbations such as pesticides in biological communities is an important basic and applied question for ecologists. In aquatic ecosystems, new evidence from microcosm experiments suggests that submerged macrophytes can buffer cladocerans from pulse exposures to the widely used insecticide malathion, and that mitigation increases with macrophyte density. However, whether these results scale up to more complex aquatic communities where ecological interactions such as competition can alter toxicity is unknown. Further, macrophyte abilities to mitigate different insecticide exposure scenarios (i.e. single versus repeated pulses) have never been tested. To address these gaps, we performed a factorial mesocosm experiment examining the influence of four macrophyte treatments (0, 10, 50, or 100 Elodea Canadensis shoots planted per mesocosm) crossed with three malathion exposure scenarios (no insecticide, single pulse, repeated pulses) on aquatic communities containing zooplankton, phytoplankton, periphyton, two snail species, and larval amphibians. In the absence of macrophytes, single malathion pulses caused short-term declines in cladoceran abundance followed by their rapid recovery, which precluded any indirect effects (i.e. trophic cascades). However, repeated malathion pulses caused cladoceran extinctions, resulting in persistent phytoplankton blooms and reduced abundance of one snail species. In contrast, with macrophytes present, even at low density, malathion had no effect on any taxa. We also discovered novel effects of macrophytes on the benthic food web. In the two highest macrophyte treatments, we observed trends of reduced periphyton biomass, decreased abundance of one snail species, and decreased amphibian time to and mass at metamorphosis. To our knowledge, this is the first evidence of negative submerged macrophyte effects on amphibians, a taxa of global conservation concern. Our findings

Submerged Macrophytes Mitigate Direct and Indirect Insecticide Effects in Freshwater Communities

Science.gov (United States)

Brogan, William R.; Relyea, Rick A.

2015-01-01

Understanding how ecological interactions mitigate the impacts of perturbations such as pesticides in biological communities is an important basic and applied question for ecologists. In aquatic ecosystems, new evidence from microcosm experiments suggests that submerged macrophytes can buffer cladocerans from pulse exposures to the widely used insecticide malathion, and that mitigation increases with macrophyte density. However, whether these results scale up to more complex aquatic communities where ecological interactions such as competition can alter toxicity is unknown. Further, macrophyte abilities to mitigate different insecticide exposure scenarios (i.e. single versus repeated pulses) have never been tested. To address these gaps, we performed a factorial mesocosm experiment examining the influence of four macrophyte treatments (0, 10, 50, or 100 Elodea Canadensis shoots planted per mesocosm) crossed with three malathion exposure scenarios (no insecticide, single pulse, repeated pulses) on aquatic communities containing zooplankton, phytoplankton, periphyton, two snail species, and larval amphibians. In the absence of macrophytes, single malathion pulses caused short-term declines in cladoceran abundance followed by their rapid recovery, which precluded any indirect effects (i.e. trophic cascades). However, repeated malathion pulses caused cladoceran extinctions, resulting in persistent phytoplankton blooms and reduced abundance of one snail species. In contrast, with macrophytes present, even at low density, malathion had no effect on any taxa. We also discovered novel effects of macrophytes on the benthic food web. In the two highest macrophyte treatments, we observed trends of reduced periphyton biomass, decreased abundance of one snail species, and decreased amphibian time to and mass at metamorphosis. To our knowledge, this is the first evidence of negative submerged macrophyte effects on amphibians, a taxa of global conservation concern. Our findings

Submerged macrophytes mitigate direct and indirect insecticide effects in freshwater communities.

Directory of Open Access Journals (Sweden)

William R Brogan

Full Text Available Understanding how ecological interactions mitigate the impacts of perturbations such as pesticides in biological communities is an important basic and applied question for ecologists. In aquatic ecosystems, new evidence from microcosm experiments suggests that submerged macrophytes can buffer cladocerans from pulse exposures to the widely used insecticide malathion, and that mitigation increases with macrophyte density. However, whether these results scale up to more complex aquatic communities where ecological interactions such as competition can alter toxicity is unknown. Further, macrophyte abilities to mitigate different insecticide exposure scenarios (i.e. single versus repeated pulses have never been tested. To address these gaps, we performed a factorial mesocosm experiment examining the influence of four macrophyte treatments (0, 10, 50, or 100 Elodea Canadensis shoots planted per mesocosm crossed with three malathion exposure scenarios (no insecticide, single pulse, repeated pulses on aquatic communities containing zooplankton, phytoplankton, periphyton, two snail species, and larval amphibians. In the absence of macrophytes, single malathion pulses caused short-term declines in cladoceran abundance followed by their rapid recovery, which precluded any indirect effects (i.e. trophic cascades. However, repeated malathion pulses caused cladoceran extinctions, resulting in persistent phytoplankton blooms and reduced abundance of one snail species. In contrast, with macrophytes present, even at low density, malathion had no effect on any taxa. We also discovered novel effects of macrophytes on the benthic food web. In the two highest macrophyte treatments, we observed trends of reduced periphyton biomass, decreased abundance of one snail species, and decreased amphibian time to and mass at metamorphosis. To our knowledge, this is the first evidence of negative submerged macrophyte effects on amphibians, a taxa of global conservation concern

Effects of addition of tilapia Oreochromis niloticus and substrates for periphyton developments on pond ecology and production in C/N-controlled freshwater prawn Macrobrachium rosenbergii farming systems

NARCIS (Netherlands)

Asaduzzaman, M.; Wahab, M.A.; Verdegem, M.C.J.; Benerjee, S.; Akter, T.; Hasan, M.M.; Azim, M.E.

2009-01-01

The present research investigated the effect of addition of tilapia and substrates for periphyton development on pond ecology, production and economic performances in C/N controlled freshwater prawn farming system. The absence and presence (0 and 0.5 individual m- 2) of tilapia were investigated in

Effects of carbohydrate source for maintaining a high C:N ratio and fish driven re-suspension on pond ecology and production in periphyton-based freshwater prawn culture systems

NARCIS (Netherlands)

Asaduzzaman, M.; Wahab, M.A.; Verdegem, M.C.J.; Adhikary, R.K.; Rahman, S.M.S.; Azim, M.E.; Verreth, J.A.J.

2010-01-01

The present research investigated the effect of carbohydrate (CH) source for maintaining a high C:N ratio, and tilapia driven bioturbation on pond ecology, production and economical performances in C/N controlled periphyton-based (C/N-CP) freshwater prawn ponds. Two carbohydrate sources (high-cost

Salinization triggers a trophic cascade in experimental freshwater communities with varying food-chain length.

Science.gov (United States)

Hintz, William D; Mattes, Brian M; Schuler, Matthew S; Jones, Devin K; Stoler, Aaron B; Lind, Lovisa; Relyea, Rick A

2017-04-01

The application of road deicing salts in northern regions worldwide is changing the chemical environment of freshwater ecosystems. Chloride levels in many lakes, streams, and wetlands exceed the chronic and acute thresholds established by the United States and Canada for the protection of freshwater biota. Few studies have identified the impacts of deicing salts in stream and wetland communities and none have examined impacts in lake communities. We tested how relevant concentrations of road salt (15, 100, 250, 500, and 1000 mg Cl - /L) interacted with experimental communities containing two or three trophic levels (i.e., no fish vs. predatory fish). We hypothesized that road salt and fish would have a negative synergistic effect on zooplankton, which would then induce a trophic cascade. We tested this hypothesis in outdoor mesocosms containing filamentous algae, periphyton, phytoplankton, zooplankton, several macroinvertebrate species, and fish. We found that the presence of fish and high salt had a negative synergistic effect on the zooplankton community, which in turn caused an increase in phytoplankton. Contributing to the magnitude of this trophic cascade was a direct positive effect of high salinity on phytoplankton abundance. Cascading effects were limited with respect to impacts on the benthic food web. Periphyton and snail grazers were unaffected by the salt-induced trophic cascade, but the biomass of filamentous algae decreased as a result of competition with phytoplankton for light or nutrients. We also found direct negative effects of high salinity on the biomass of filamentous algae and amphipods (Hyalella azteca) and the mortality of banded mystery snails (Viviparus georgianus) and fingernail clams (Sphaerium simile). Clam mortality was dependent on the presence of fish, suggesting a non-consumptive interactive effect with salt. Our results indicate that globally increasing concentrations of road salt can alter community structure via both direct

Effects of stocking density of freshwater prawn Macrobrachium rosenbergii and addition of different levels of tilapia Oreochromis niloticus on production in C/N controlled periphyton based system

NARCIS (Netherlands)

Asaduzzaman, M.; Wahab, M.A.; Verdegem, M.C.J.; Mondal, M.N.; Azim, M.E.

2009-01-01

An on-station trial was conducted to evaluate the effect of stocking density of freshwater prawn and addition of different levels of tilapia on production in carbon/nitrogen (C/N) controlled periphyton based system. The experiment had a 2 × 3 factorial design, in which two levels of prawn stocking

Water Quality Criteria for Nitroglycerin.

Science.gov (United States)

1986-07-01

periphyton being dominated by a coccoid myxophycean (blue- green alga) and the phytoplankton being dominated by two species of the genus Scoedesmu...not nitrogly- cerin related . Survival of both larvae and adults of the first genera- tion was significantly (P = 0.05) reduced at concentrations of...after a 4-week colonization period. The algal community was similarly affected in the RP pond. The periphyton and phytoplakton communities were both

Responses of Chironomidae (Diptera; Insecta to the exclusion of shrimps and Ephemeroptera in a coastal forest stream, Rio de Janeiro, Brazil

Directory of Open Access Journals (Sweden)

ML. Souza

Full Text Available In a benthic community on a continuous flat granite substrate in a third-order coastal forest stream, the dominant chironomid (Cricotopus increased in number when shrimps (Macrobrachium olfersi and Potimirim glabra and baetid ephemeropterans were excluded by electricity. The response appeared to be mediated by an increase in periphyton and sediments, rather than a reduction of direct predation or interference. Chironomids, periphyton and sediments decreased significantly compared to the control when shrimps only were excluded. Baetid ephemeropteran appeared to be the most important determinants of periphyton and sediment mass; the density of chironomids appeared to follow the quantity of periphyton and sediments.

The use of epilithic Antarctic lichens (Usnea aurantiacoatra and U. antartica) to determine deposition patterns of heavy metals in the Shetland Islands, Antarctica.

Science.gov (United States)

Poblet, A; Andrade, S; Scagliola, M; Vodopivez, C; Curtosi, A; Pucci, A; Marcovecchio, J

1997-11-27

Trace-metal contents were recorded for the epilithic antarctic lichens Usnea aurantiacoatra and U. antartica, sampled close to the Argentine scientific station 'Jubany' on '25 de Mayo' (King George) Island, in the Southern Shetland Archipelago (Antarctica). The corresponding heavy-metal levels have been measured through atomic absorption spectrophotometry, following internationally accepted analytical methods. The results obtained support the hypothesis that an atmospheric circulation of trace metals exists on the assessed area, and the activities developed at the different scientific stations located on this island would be a potential source of heavy metals to the evaluated environment. The geographical distribution of trace metals atmospherically transported in the area close to 'Jubany Station' was studied through the corresponding metal contents of the assessed lichens. Finally, the suitability of both analyzed lichen species, Usnea aurantiacoatra and U. antartica, as biological indicators for quantitative monitoring of airborne metals for this antarctic environment was recognized.

Long-term changes in community assembly, resistance, and resilience following experimental floods.

Science.gov (United States)

Robinson, Christopher T

2012-10-01

This study examined the long-term changes in community assembly, resistance, and resilience of macroinvertebrates following 10 years of experimental floods in a flow regulated river. Physico-chemistry, macroinvertebrates, and periphyton biomass were monitored before and sequentially after each of 22 floods, and drift/seston was collected during six separate floods over the study period. The floods reduced the density and taxon richness of macroinvertebrates, and a nonmetric dimensional scaling (NMDS) analysis distinguished temporal shifts in community assembly. Resistance (measured as the relative lack of loss in density) tofloods varied among taxa, and the abundance of resistant taxa was related to the temporal changes in community assembly. Community resistance was inversely related to flood magnitude with all larger floods (> 25 m3/s, > 16-fold over baseflow) reducing densities by > 75% regardless of flood year, whereas smaller floods (floods. No relationship was found between flood magnitude and the relative loss in periphyton biomass. Resilience was defined as the recovery slope (positive slope of a parameter with time following each flood) and was unrelated to shifts in community assembly or resistance. Macroinvertebrate drift and seston demonstrated hysteresis (i.e., a temporal response in parameter quantity with change in discharge) during each flood, although larger floods typically had two peaks in both parameters. The first peak was a response to the initial increases in flow, whereas the second peak was associated with streambed disturbance (substrate mobility) and side-slope failure causing increased scour. Drift density was 3-9 times greater and that of seston 3-30 times greater during larger floods than smaller floods. These results demonstrate temporal shifts in macroinvertebrate community assembly toward a pre-dam assemblage following sequential floods in this flow regulated river, thus confirming the ecological role of habitat filtering in

Volunteer stream monitoring: Do the data quality and monitoring experience support increased community involvement in freshwater decision making?

Directory of Open Access Journals (Sweden)

Richard G. Storey

2016-12-01

Full Text Available Recent freshwater policy reforms in New Zealand promote increased community involvement in freshwater decision making and management. Involving community members in scientific monitoring increases both their knowledge and their ability to discuss this knowledge with professionals, potentially increasing their influence in decision-making processes. However, these interactions rarely occur because, in particular, of perceptions that volunteer-collected data are unreliable. We assessed the agreement between volunteer (community group and local government (regional council data at nine stream sites across New Zealand. Over 18 months, community groups and regional council staff monitored, in parallel, a common set of water quality variables, physical habitat, periphyton and benthic macroinvertebrates that are routinely used by regional councils for statutory state of environment reporting. Community groups achieved close agreement (correlations ≥ 0.89, bias < 1% with regional councils for temperature, electrical conductivity, visual water clarity, and Escherichia coli. For dissolved oxygen, nitrate, and pH, correlations were weaker (0.2, 0.53, and 0.4, respectively. Volunteer assessments of physical habitat were as consistent over time as those of councils. For visual assessments of thick periphyton growths (% streambed cover, volunteers achieved a correlation of 0.93 and bias of 0.1% relative to councils. And for a macroinvertebrate biotic index that indicates water and habitat quality, correlation was 0.88, bias was < 5%, and the average difference was 12% of the index score. Volunteers showed increased awareness of local freshwaters, understanding of stream ecosystems, and attentiveness to local and national freshwater issues. Most volunteers had shared their knowledge and interest with others in their community. Most groups had developed relationships with their regional council, and some volunteers became more interested in engaging in

Long-term hydrologic effects on marsh plant community structure in the southern Everglades

Science.gov (United States)

Busch, David E.; Loftus, W.F.; Bass, O.L.

1998-01-01

Although large-scale transformation of Everglades landscapes has occurred during the past century, the patterns of association among hydrologic factors and southern Everglades freshwater marsh vegetation have not been well-defined. We used a 10-year data base on the aquatic biota of Shark Slough to classify vegetation and describe plant community change in intermediate- to long-hydroperiod Everglades marshes. Study area marsh vegetation was quantitatively grouped into associations dominated by 1) Cladium jamaicense, 2) a group of emergents including Eleocharis cellulosa, Sagittaria lancifolia, and Rhyncospora tracyi, 3) taxa associated with algal mats (Utricularia spp. and Bacopa caroliniana), and 4) the grasses Panicum hemitomon and Paspalidium geminatum. During the decade evaluated, the range of water depths that characterized our study sites approached both extremes depicted in the 40-year hydrologic record for the region. Water depths were near the long-term average during the mid-1980s, declined sharply during a late 1980s drought, and underwent a prolonged increase from 1991 through 1995. Overall macrophyte cover varied inversely with water depth, while the response of periphyton was more complex. An ordination analysis, based on plant species abundance, revealed that study area vegetation structure was associated with hydrologic patterns. Marsh plant community structure showed evidence of cyclic interannual variation corresponding to hydrologic change over the decade evaluated. Lower water depths, the occurrence of marl substrates, and high periphyton cover were correlated. These factors contributed to reduced macrophyte cover in portions of the study area from which water had been diverted.

Ecological and evolutionary effects of stickleback on community structure.

Directory of Open Access Journals (Sweden)

Simone Des Roches

Full Text Available Species' ecology and evolution can have strong effects on communities. Both may change concurrently when species colonize a new ecosystem. We know little, however, about the combined effects of ecological and evolutionary change on community structure. We simultaneously examined the effects of top-predator ecology and evolution on freshwater community parameters using recently evolved generalist and specialist ecotypes of three-spine stickleback (Gasterosteus aculeatus. We used a mesocosm experiment to directly examine the effects of ecological (fish presence and density and evolutionary (phenotypic diversity and specialization factors on community structure at lower trophic levels. We evaluated zooplankton biomass and composition, periphyton and phytoplankton chlorophyll-a concentration, and net primary production among treatments containing different densities and diversities of stickleback. Our results showed that both ecological and evolutionary differences in the top-predator affect different aspects of community structure and composition. Community structure, specifically the abundance of organisms at each trophic level, was affected by stickleback presence and density, whereas composition of zooplankton was influenced by stickleback diversity and specialization. Primary productivity, in terms of chlorophyll-a concentration and net primary production was affected by ecological but not evolutionary factors. Our results stress the importance of concurrently evaluating both changes in density and phenotypic diversity on the structure and composition of communities.

Entrapped Sediments as a Source of Phosphorus in Epilithic Cyanobacterial Proliferations in Low Nutrient Rivers

Science.gov (United States)

Wood, Susanna A.; Depree, Craig; Brown, Logan; McAllister, Tara; Hawes, Ian

2015-01-01

Proliferations of the benthic mat-forming cyanobacteria Phormidium have been reported in rivers worldwide. Phormidium commonly produces natural toxins which pose a health risk to animal and humans. Recent field studies in New Zealand identified that sites with Phormidium proliferations consistently have low concentrations of water column dissolved reactive phosphorus (DRP). Unlike other river periphyton, Phormidium mats are thick and cohesive, with water and fine sediment trapped in a mucilaginous matrix. We hypothesized that daytime photosynthetic activity would elevate pH inside the mats, and/or night time respiration would reduce dissolved oxygen. Either condition could be sufficient to facilitate desorption of phosphates from sediment incorporated within mats, thus allowing Phormidium to utilize it for growth. Using microelectrodes, optodes and pulse amplitude modulation fluorometry we demonstrated that photosynthetic activity results in elevated pH (>9) during daytime, and that night-time respiration causes oxygen depletion (river water and this, together with elevated concentrations of elements, including iron, suggest phosphorus release from entrapped sediment. Sequential extraction of phosphorus from trapped sediment was used to investigate the role of sediment at sites on the Mangatainoka River (New Zealand) with and without Phormidium proliferations. Deposition of fine sediment (sediment can provide a source of phosphorus to support Phormidium growth and proliferation. PMID:26479491

Non-destructive sampling of rock-dwelling microbial communities using sterile adhesive tape.

Science.gov (United States)

Cutler, Nick A; Oliver, Anna E; Viles, Heather A; Whiteley, Andrew S

2012-12-01

Building stone provides a habitat for an array of microorganisms, many of which have been demonstrated to have a deleterious effect on the appearance and/or structural integrity of stone masonry. It is essential to understand the composition and structure of stone-dwelling (lithobiontic) microbial communities if successful stone conservation strategies are to be applied, particularly in the face of global environmental change. Ideally, the techniques used to sample such assemblages should be non-destructive due to the sensitive conservation status of many stone buildings. This paper quantitatively assesses the performance of sterile adhesive tape as a non-destructive sampling technique and compares the results of tape sampling with an alternative, destructive, sampling method. We used DNA fingerprinting (TRFLP) to characterise the algal, fungal and bacterial communities living on a stone slab. Our results demonstrate that tape sampling may be used to collect viable quantities of microbial DNA from environmental samples. This technique is ideally suited to the sampling of microbial biofilms, particularly when these communities are dominated by green algae. It provides a good approximation of total community diversity (i.e. the aggregate diversity of epilithic and endolithic communities). Tape sampling is straightforward, rapid and cost effective. When combined with molecular analytical techniques, this sampling method has the potential to make a major contribution to efforts to understand the structure of lithobiontic microbial communities and our ability to predict the response of such communities to future environmental change. Copyright © 2012 Elsevier B.V. All rights reserved.

Historical and current atmospheric deposition to the epilithic lichen Xanthoparmelia in Maricopa County, Arizona

Energy Technology Data Exchange (ETDEWEB)

Zschau, T.; Getty, S.; Gries, C.; Ameron, Y.; Zambrano, A.; Nash, T.H

2003-09-01

Spatial variation of elemental deposition to lichen receptors across Maricopa County, Arizona, USA is documented for 1998 and historical trends relative to 1974 are documented. - Spatial patterns of atmospheric deposition of trace elements to an epilithic lichen were assessed using a spatial grid of 28 field sites in 1998 throughout Maricopa County, Arizona, USA. In addition, samples of Xanthoparmelia spp. from Arizona State University lichen herbarium material (1975-1976) was utilized for a limited number of sites in order to explore temporal trends. The lichen material was cleaned, wet digested and analyzed by ICP-MS for a suite of elemental concentrations [antimony (Sb), cadmium (Cd), cerium (Ce), chromium (Cr), cobalt (Co), copper (Cu), dysprosium (Dy), europium (Eu), gadolinium (Gd), gold (Au), holmium (Ho), lead (Pb), lutetium (Lu), neodymium (Nd), nickel (Ni), palladium (Pd), platinum (Pt), praseodymium (Pr), samarium (Sm), scandium (Sc), silver (Ag), terbium (Tb), thulium (Tm), tin (Sn), uranium (U), ytterbium (Yb), yttrium (Y), and zinc (Zn)]. Cluster analysis and principal component analysis suggest three major factors, which, depending on regional aerosol fractionation, explain most of the variation in elemental signatures: (1) a group of widely distributed rare earth elements (2) a highly homogenous Co, Cr, Ni, and Sc component representing the influence of mafic rocks, and (3) anthropogenic emissions. Elemental concentrations in Maricopa County lichens were generally comparable to those reported for relatively unpolluted areas. Only highly urbanized regions, such as the greater Phoenix Metropolitan Area and the NW corner of the county, exhibited elevated concentrations for Zn, Cu, Pb, and Cd. Lead levels in lichens have fallen over the last 30 years by 71%, while Zn concentrations for some regions have increased by as much as 245%. From the spatial pattern of elemental deposition for Cd, Cu, Ni, Pr, Pb, and Cu, we infer that agriculture, mining

Historical and current atmospheric deposition to the epilithic lichen Xanthoparmelia in Maricopa County, Arizona

International Nuclear Information System (INIS)

Zschau, T.; Getty, S.; Gries, C.; Ameron, Y.; Zambrano, A.; Nash, T.H.

2003-01-01

Spatial variation of elemental deposition to lichen receptors across Maricopa County, Arizona, USA is documented for 1998 and historical trends relative to 1974 are documented. - Spatial patterns of atmospheric deposition of trace elements to an epilithic lichen were assessed using a spatial grid of 28 field sites in 1998 throughout Maricopa County, Arizona, USA. In addition, samples of Xanthoparmelia spp. from Arizona State University lichen herbarium material (1975-1976) was utilized for a limited number of sites in order to explore temporal trends. The lichen material was cleaned, wet digested and analyzed by ICP-MS for a suite of elemental concentrations [antimony (Sb), cadmium (Cd), cerium (Ce), chromium (Cr), cobalt (Co), copper (Cu), dysprosium (Dy), europium (Eu), gadolinium (Gd), gold (Au), holmium (Ho), lead (Pb), lutetium (Lu), neodymium (Nd), nickel (Ni), palladium (Pd), platinum (Pt), praseodymium (Pr), samarium (Sm), scandium (Sc), silver (Ag), terbium (Tb), thulium (Tm), tin (Sn), uranium (U), ytterbium (Yb), yttrium (Y), and zinc (Zn)]. Cluster analysis and principal component analysis suggest three major factors, which, depending on regional aerosol fractionation, explain most of the variation in elemental signatures: (1) a group of widely distributed rare earth elements (2) a highly homogenous Co, Cr, Ni, and Sc component representing the influence of mafic rocks, and (3) anthropogenic emissions. Elemental concentrations in Maricopa County lichens were generally comparable to those reported for relatively unpolluted areas. Only highly urbanized regions, such as the greater Phoenix Metropolitan Area and the NW corner of the county, exhibited elevated concentrations for Zn, Cu, Pb, and Cd. Lead levels in lichens have fallen over the last 30 years by 71%, while Zn concentrations for some regions have increased by as much as 245%. From the spatial pattern of elemental deposition for Cd, Cu, Ni, Pr, Pb, and Cu, we infer that agriculture, mining

Spatial and temporal variation of algal assemblages in six Midwest agricultural streams having varying levels of atrazine and other physicochemical attributes

Energy Technology Data Exchange (ETDEWEB)

Andrus, J. Malia, E-mail: andrusm@waterborne-env.com [Waterborne Environmental, Inc., 2001 South First Street, Suite 109, Champaign, IL 61820 (United States); Winter, Diane, E-mail: dwinter1@juno.com [Rhithron Associates, Inc., 33 Fort Missoula Rd., Missoula, MT 59804 (United States); Algal Analysis, LLC, Missoula, MT (United States); Scanlan, Michael, E-mail: mscanlan@maptech-inc.com [MapTech, Inc., 3154 State Street, Blacksburg, VA 24060 (United States); Sullivan, Sean, E-mail: ssullivan@rhithron.com [Rhithron Associates, Inc., 33 Fort Missoula Rd., Missoula, MT 59804 (United States); Bollman, Wease, E-mail: wbollman@rhithron.com [Rhithron Associates, Inc., 33 Fort Missoula Rd., Missoula, MT 59804 (United States); Waggoner, J.B., E-mail: jwaggoner@inovatia.com [Inovatia, Inc., 120 East Davis Street, Fayette, MO 65248 (United States); Hosmer, Alan J., E-mail: alan.hosmer@syngenta.com [Syngenta Crop Protection, LLC, 410 Swing Rd., Greensboro, NC 27419 (United States); Brain, Richard A., E-mail: richard.brain@syngenta.com [Syngenta Crop Protection, LLC, 410 Swing Rd., Greensboro, NC 27419 (United States)

2015-02-01

Potential effects of pesticides on stream algae occur alongside complex environmental influences; in situ studies examining these effects together are few, and have not typically controlled for collinearity of variables. We monitored the dynamics of periphyton, phytoplankton, and environmental factors including atrazine, and other water chemistry variables at 6 agricultural streams in the Midwest US from spring to summer of 2011 and 2012, and used variation partitioning of community models to determine the community inertia that is explained uniquely and/or jointly by atrazine and other environmental factors or groups of factors. Periphyton and phytoplankton assemblages were significantly structured by year, day of year, and site, and exhibited dynamic synchrony both between site–years and between periphyton and phytoplankton in the same site–year. The majority of inertia in the models (55.4% for periphyton, 68.4% for phytoplankton) was unexplained. The explained inertia in the models was predominantly shared (confounded) between variables and variable groups (13.3, 30.9%); the magnitude of inertia that was explained uniquely by variable groups (15.1, 18.3%) was of the order hydroclimate > chemistry > geography > atrazine for periphyton, and chemistry > hydroclimate > geography > atrazine for phytoplankton. The variables most influential to the assemblage structure included flow and velocity variables, and time since pulses above certain thresholds of nitrate + nitrite, total phosphorus, total suspended solids, and atrazine. Time since a ≥ 30 μg/L atrazine pulse uniquely explained more inertia than time since pulses ≥ 10 μg/L or daily or historic atrazine concentrations; this result is consistent with studies concluding that the effects of atrazine on algae typically only occur at ≥ 30 μg/L and are recovered from. - Highlights: • We monitored algal communities at 6 Midwest streams receiving atrazine in 2011 and 2012. • Partitioning of CCA models of

Spatial and temporal variation of algal assemblages in six Midwest agricultural streams having varying levels of atrazine and other physicochemical attributes

International Nuclear Information System (INIS)

Andrus, J. Malia; Winter, Diane; Scanlan, Michael; Sullivan, Sean; Bollman, Wease; Waggoner, J.B.; Hosmer, Alan J.; Brain, Richard A.

2015-01-01

Potential effects of pesticides on stream algae occur alongside complex environmental influences; in situ studies examining these effects together are few, and have not typically controlled for collinearity of variables. We monitored the dynamics of periphyton, phytoplankton, and environmental factors including atrazine, and other water chemistry variables at 6 agricultural streams in the Midwest US from spring to summer of 2011 and 2012, and used variation partitioning of community models to determine the community inertia that is explained uniquely and/or jointly by atrazine and other environmental factors or groups of factors. Periphyton and phytoplankton assemblages were significantly structured by year, day of year, and site, and exhibited dynamic synchrony both between site–years and between periphyton and phytoplankton in the same site–year. The majority of inertia in the models (55.4% for periphyton, 68.4% for phytoplankton) was unexplained. The explained inertia in the models was predominantly shared (confounded) between variables and variable groups (13.3, 30.9%); the magnitude of inertia that was explained uniquely by variable groups (15.1, 18.3%) was of the order hydroclimate > chemistry > geography > atrazine for periphyton, and chemistry > hydroclimate > geography > atrazine for phytoplankton. The variables most influential to the assemblage structure included flow and velocity variables, and time since pulses above certain thresholds of nitrate + nitrite, total phosphorus, total suspended solids, and atrazine. Time since a ≥ 30 μg/L atrazine pulse uniquely explained more inertia than time since pulses ≥ 10 μg/L or daily or historic atrazine concentrations; this result is consistent with studies concluding that the effects of atrazine on algae typically only occur at ≥ 30 μg/L and are recovered from. - Highlights: • We monitored algal communities at 6 Midwest streams receiving atrazine in 2011 and 2012. • Partitioning of CCA models of

Effects of the pyrethroid insecticide cypermethrin on a freshwater community studied under field conditions. II. Direct and indirect effects on the species composition

DEFF Research Database (Denmark)

Wendt-Rasch, Lina; Friberg-Jensen, Ursula; Woin, Per

2003-01-01

species were calculated using inverse regression and revealed that copepod nauplii were the most sensitive (NEC=0.01 microg/l) of the crustacean groups examined. The observed alterations of the species composition of the autotrophic communities as well as of the rotifers were most likely caused indirectly...... cypermethrin concentrations, ranging from 0.01 to 6 microg/l. This paper is the second in a series of two and describes the effects on the species composition of the crustacean, rotifer, periphyton and phytoplankton communities. Multivariate ordination technique (redundancy analysis (RDA) combined with Monte...... Carlo permutation tests) showed that exposure to cypermethrin caused significant changes in the species composition of the communities. Changes in the structure of the communities were observed following exposure to a nominal concentration of 0.13 microg cypermethrin per litre above. The direct acute...

Toxicity of the pharmaceutical clotrimazole to marine microalgal communities

International Nuclear Information System (INIS)

Porsbring, Tobias; Blanck, Hans; Tjellstroem, Henrik; Backhaus, Thomas

2009-01-01

Clotrimazole belongs to the group of 14α-demethylase inhibiting fungicides. It is widely used in human and veterinary medicine and has been identified as a priority pollutant for the marine environment. However, the toxicity of clotrimazole to marine primary producers is largely unknown. We therefore sampled natural microalgal communities (periphyton) and exposed them to concentration series of clotrimazole over 4 days. 50 pmol/L clotrimazole caused a concentration-dependent accumulation of C14α-methylated sterol precursors, which coincided with a decrease in algal-specific C14-desmethyl sterols. This indicates an inhibition of algal 14α-demethylases already at environmental concentrations. A clotrimazole concentration of 500 pmol/L reduced total sterol content to 64% of control level. Community chlorophyll a content was affected by clotrimazole in a bi-phasic manner with first reductions becoming visible at 500 pmol/L, along with indications of an altered cycling of photoprotective xanthophyll pigments. Concentrations of 10-100 nmol/L and higher caused large reductions in community growth, and changed community pigment profiles in a concentration-dependent monotonous manner. The study further indicated that diatoms use obtusifoliol as a natural substrate for 14α-demethylase, just as higher plants do but also utilize norlanosterol

Data for a regional approach to the development of an effects-based nutrient criterion for wadable streams

Science.gov (United States)

Crawford, J. Kent; Loper, Connie A.; Beaman, Joseph R.; Soehl, Anna G.; Brown, Will S.

2007-01-01

States are required by the U.S. Environmental Protection Agency to establish nutrient criteria (concentrations of nutrients above which water quality is deteriorated) as part of their water-quality regulations. A study of wadable streams in the Mid-Atlantic Region was undertaken by the U.S. Geological Survey, the U.S. Environmental Protection Agency, and the Maryland Department of the Environment, with assistance from the Pennsylvania Department of Environmental Protection, to help define current concentrations of nutrients in streams with the goal of associating different nutrient-concentration levels with their effects on water quality. During the summers of 2004 and 2005, diel concentrations of dissolved oxygen, nutrient concentrations, concentrations of chlorophyll a in attached algae, and algal-community structure were measured at 46 stream sites in Maryland, Pennsylvania, Virginia, and West Virginia. Data from this work can be used by individual state agencies to define nutrient criteria. Quality-control measures for the study included submitting blank samples, duplicate samples, and reference samples for analysis of nutrients, total organic carbon, chlorophyll a, and algal biomass. Duplicate and split samples were submitted for periphyton identifications. Three periphyton split samples were sent to an independent lab for a check on periphyton identifications. Neither total organic carbon nor nutrients were detected in blank samples. Concentrations of nutrients and total organic carbon were similar for most duplicate sample pairs, with the exception of a duplicate pair from Western Run. Concentrations of ammonia plus organic nitrogen for this duplicate pair differed by as much as 34 percent. Total organic carbon for the duplicate pair from Western Run differed by 102 percent. The U.S. Geological Survey National Water Quality Laboratory performance on the only valid reference sample submitted was excellent; the relative percent difference values were no larger

Methods for collecting algal samples as part of the National Water-Quality Assessment Program

Science.gov (United States)

Porter, Stephen D.; Cuffney, Thomas F.; Gurtz, Martin E.; Meador, Michael R.

1993-01-01

Benthic algae (periphyton) and phytoplankton communities are characterized in the U.S. Geological Survey's National Water-Quality Assessment Program as part of an integrated physical, chemical, and biological assessment of the Nation's water quality. This multidisciplinary approach provides multiple lines of evidence for evaluating water-quality status and trends, and for refining an understanding of the factors that affect water-quality conditions locally, regionally, and nationally. Water quality can be characterized by evaluating the results of qualitative and quantitative measurements of the algal community. Qualitative periphyton samples are collected to develop of list of taxa present in the sampling reach. Quantitative periphyton samples are collected to measure algal community structure within selected habitats. These samples of benthic algal communities are collected from natural substrates, using the sampling methods that are most appropriate for the habitat conditions. Phytoplankton samples may be collected in large nonwadeable streams and rivers to meet specific program objectives. Estimates of algal biomass (chlorophyll content and ash-free dry mass) also are optional measures that may be useful for interpreting water-quality conditions. A nationally consistent approach provides guidance on site, reach, and habitat selection, as well as information on methods and equipment for qualitative and quantitative sampling. Appropriate quality-assurance and quality-control guidelines are used to maximize the ability to analyze data locally, regionally, and nationally.

Assessing the influence of surface roughness on the epilithic colonisation of limestones by non-contact techniques

Directory of Open Access Journals (Sweden)

Miller, A. Z.

2012-09-01

Full Text Available The importance of stone colonisation by microorganisms has led to an extensive literature on mechanisms and rates of physicochemical degradation of stone surface, both in laboratory and field contexts. Biological colonisation of a stone surface depends on intrinsic stone parameters like mineral composition, texture, porosity, and permeability, as well as on environmental parameters. In the present study, quantification of stone surface roughness and its relationship to epilithic colonisation was demonstrated for three types of limestones throughout non-destructive techniques, namely optical surface roughness instrument and digital image analysis. According to the roughness average (Ra and mean roughness depth (Rz determined for Ançã limestone, Lioz limestone and Lecce stone, it can be concluded that great surface roughness stones render them prone to microbial colonisation.La colonización de la piedra por microorganismos ha generado una extensa literatura sobre los mecanismos y tasas de degradación fisicoquímica de las superficies pétreas, tanto en laboratorio como en estudios de campo. La colonización biológica de piedra de construcción depende de parámetros intrínsecos como son su composición mineral, textura, porosidad y permeabilidad, así como de parámetros ambientales. Este estudio demuestra la relación entre la rugosidad superficial de la piedra y la colonización epilítica, cuantificada en tres tipos de caliza mediante técnicas no destructivas: medida de la rugosidad superficial usando un perfilómetro óptico y análisis digital de imágenes. De acuerdo con la rugosidad media aritmética (Ra y la amplitud media de rugosidad (Rz, determinadas para la caliza de Ançã, la caliza de Lioz y la piedra de Lecce, puede concluirse que las piedras con alta rugosidad superficial son más propensas a la colonización microbiana.

Microbial, algal, and fungal strategies for manganese oxidation at a Shade Township coal mine, Somerset County, Pennsylvania

International Nuclear Information System (INIS)

Robbins, E.I.; Brant, D.L.; Ziemkiewicz, P.F.

1999-01-01

Successful designs to eliminate Mn from mine discharge are necessary for both restoring abandoned mine lands and permitting the mining of high sulfur coal in the eastern United States. A passive in-line system that meets Mn discharge limits was built at the discharge from the former Shade Township coal mine in south central Pennsylvania. Qualitative research on monthly changes in the microbial and algal community that removes Mn is underway. Epilithic attachment of microorganisms was analyzed on artificial (glass microscope slides) and natural substrates (limestone thin sections) that were immersed in surface water for one month periods over 6 months. Organisms attached to both glass and limestone substrates. Limestone became coated with 34--86% more Mn that did glass surfaces. Light microscopy revealed 12 different strategies are being used by bacteria, cyan bacteria, diatoms, green algae, and fungi to oxidize Mn. the dominant method used by the epilithic community to oxidize Mn is coating of holdfasts by the iron bacterium, Liptothrix discophora, and the green alga, Ulothrix sp. Other methods for Mn removal by oxidation include coating of individual cells, filaments/sheaths/hyphae, extracellular polysaccharides, and biofilms. The unplanned community at the site is multifaceted and extremely efficient in its Mn removal ability. Community interactions or complexity may play roles in the stability of the ecosystem and the efficiency of its Mn oxidizing ability

Microbial, algal, and fungal strategies for manganese oxidation at a Shade Township coal mine, Somerset County, Pennsylvania

Energy Technology Data Exchange (ETDEWEB)

Robbins, E.I.; Brant, D.L.; Ziemkiewicz, P.F.

1999-07-01

Successful designs to eliminate Mn from mine discharge are necessary for both restoring abandoned mine lands and permitting the mining of high sulfur coal in the eastern United States. A passive in-line system that meets Mn discharge limits was built at the discharge from the former Shade Township coal mine in south central Pennsylvania. Qualitative research on monthly changes in the microbial and algal community that removes Mn is underway. Epilithic attachment of microorganisms was analyzed on artificial (glass microscope slides) and natural substrates (limestone thin sections) that were immersed in surface water for one month periods over 6 months. Organisms attached to both glass and limestone substrates. Limestone became coated with 34--86% more Mn that did glass surfaces. Light microscopy revealed 12 different strategies are being used by bacteria, cyan bacteria, diatoms, green algae, and fungi to oxidize Mn. the dominant method used by the epilithic community to oxidize Mn is coating of holdfasts by the iron bacterium, Liptothrix discophora, and the green alga, Ulothrix sp. Other methods for Mn removal by oxidation include coating of individual cells, filaments/sheaths/hyphae, extracellular polysaccharides, and biofilms. The unplanned community at the site is multifaceted and extremely efficient in its Mn removal ability. Community interactions or complexity may play roles in the stability of the ecosystem and the efficiency of its Mn oxidizing ability.

Effects of land use, stream habitat, and water quality on biological communities of wadeable streams in the Illinois River Basin of Arkansas, 2011 and 2012

Science.gov (United States)

Petersen, James C.; Justus, B.G.; Meredith, Bradley J.

2014-01-01

The Illinois River Basin includes an area of diverse land use in northwestern Arkansas. Land-use data collected in 2006 indicate that most of the land in the basin is agricultural. The agricultural land is used primarily for production of poultry and cattle. Eighteen sites were selected from the list of candidate sites based on drainage area, land use, presence or absence of an upstream wastewater-treatment plant, water quality, and other information gathered during the reconnaissance. An important consideration in the process was to select sites along gradients of forest to urban land use and forest to agricultural land use. Water-quality samples were collected for analysis of nutrients, and a multiparameter field meter was used to measure water temperature, specific conductance, pH, and dissolved oxygen. Streamflow was measured immediately following the water-quality sampling. Macroalgae coverage was estimated and periphyton, macroinvertebrate, and fish communities were sampled at each site. Stream habitat also was assessed. Many types of land-use, water-quality, and habitat factors affected one or more aspects of the biological communities. Several macroinvertebrate and fish metrics changed in response to changes in percent forest; sites that would be considered most disturbed, based on these metrics, are sites with the highest percentages of urban land use in their associated basins. The presence of large mats of macroalgae was one of the most noticeable biological characteristics in several streams within the Illinois River Basin. The highest macroalgae percent cover values were recorded at four sites downstream from wastewater-treatment plants. Macroalgae percent cover was strongly correlated only with bed substrate size, canopy closure, and specific conductance. Periphyton metrics were most often and most strongly correlated with riparian shading, specific conductance, substrate turbidity, percent agriculture, poultry house density, and unpaved road density

Exposure of phototrophs to 548 days in low Earth orbit: microbial selection pressures in outer space and on early earth.

Science.gov (United States)

Cockell, Charles S; Rettberg, Petra; Rabbow, Elke; Olsson-Francis, Karen

2011-10-01

An epilithic microbial community was launched into low Earth orbit, and exposed to conditions in outer space for 548 days on the European Space Agency EXPOSE-E facility outside the International Space Station. The natural phototroph biofilm was augmented with akinetes of Anabaena cylindrica and vegetative cells of Nostoc commune and Chroococcidiopsis. In space-exposed dark controls, two algae (Chlorella and Rosenvingiella spp.), a cyanobacterium (Gloeocapsa sp.) and two bacteria associated with the natural community survived. Of the augmented organisms, cells of A. cylindrica and Chroococcidiopsis survived, but no cells of N. commune. Only cells of Chroococcidiopsis were cultured from samples exposed to the unattenuated extraterrestrial ultraviolet (UV) spectrum (>110 nm or 200 nm). Raman spectroscopy and bright-field microscopy showed that under these conditions the surface cells were bleached and their carotenoids were destroyed, although cell morphology was preserved. These experiments demonstrate that outer space can act as a selection pressure on the composition of microbial communities. The results obtained from samples exposed to >200 nm UV (simulating the putative worst-case UV exposure on the early Earth) demonstrate the potential for epilithic colonization of land masses during that time, but that UV radiation on anoxic planets can act as a strong selection pressure on surface-dwelling organisms. Finally, these experiments have yielded new phototrophic organisms of potential use in biomass and oxygen production in space exploration.

From Greenland to green lakes: Cultural eutrophication and the loss of benthic pathways in lakes

DEFF Research Database (Denmark)

Vadeboncoeur, Y.; Jeppesen, E.; Zanden, M. J. V.

2003-01-01

Benthic community responses to lake eutrophication are poorly understood relative to pelagic responses. We compared phytoplankton and periphyton productivity along a eutrophication gradient in Greenland, U.S., and Danish lakes. Phytoplankton productivity increased along the phosphorus gradient (t...

Effects of copper on species composition of periphyton in a Sierra Nevada, California, stream

Energy Technology Data Exchange (ETDEWEB)

Leland, H.V.; Carter, J.L.

1984-06-01

Changes in species composition of the periphyton of an oliotrophic, Sierra Nevada stream continuously dosed for 1 year at three concentrations of copper (2.5, 5 and 10..mu..g 1/sup -1/ Cu/sub T/; approximately 12, 25 and 50 ng 1/sup -1/ Cu/sup 2 +/) were determined. The numerically most abundant taxa were Bacillariophyceae (Achnanthes minutissima, Cocconeis placentula, Cymbella microcephala, C. sinuata, Fragilaria construens, F. crotonensis, Navicula spp., Synedra acus and S. rumpens), and the Cyanophyta Lynbya spp., a co-dominant during spring and summer. Population densities of Lyngbya spp. were markedly reduced at all test concentrations of copper. Population densities of the principal Chlorophyta (Spirogyra spp. and Cladophora spp.) and the diatom Amphipleura pellucida were reduced at 5 ..mu..g 1/sup -1/ Cu/sub T/. Of the twenty-two most abundant taxa, sixteen were reduced in abundance by continuous exposure to 10 ..mu..g 1/sup -1/ Cu/sub T/. There was no commensurate reduction in standing crop (total number of individuals of all taxa). Achnanthes minutissima, a co-dominant in the control, was the primary replacement species. Other taxa that were more abundant at 5 ..mu..g 1/sup -1/ Cu/sub T/ than in the control were Ceratoneis arcus, Cocconeis placentula, Navicula spp. and Synedra rumpens. Only A. minutissima and Calothrix spp. were more abundant at l10 ..mu..g 1/sup -1/ than in the control. Three resemblance measures (Canberra metric, Bray-Curtis and Dice) and diversity (Brillouin's) were evaluated for detecting differences in species composition among experimental stream sections. The Canberra metric, an index sensitive to proportional rather than absolute differences, was the most informative of these indices.

Transfer of mercury and methylmercury along macroinvertebrate food chains in a floodplain lake of the Beni River, Bolivian Amazonia

International Nuclear Information System (INIS)

Molina, Carlos Israel; Gibon, Francois-Marie; Duprey, Jean-Louis; Dominguez, Eduardo; Guimaraes, Jean-Remy D.; Roulet, Marc

2010-01-01

We have evaluated the mercury and methylmercury transfers to and within the macroinvertebrate communities of a floodplain lake of the Beni River basin, Bolivia, during three hydrological seasons and in two habitats (open water and vegetation belt). Using the stable isotopes δ 13 C and δ 15 N, six trophic chains were identified during a previous study. Four are based on only one source: seston, organic matter from the bottom sediment, periphyton and macrophytes. Two are based on mixed sources (seston and periphyton in one case, periphyton and macrophytes in the other). During sampling, we found only one taxon that had surface sediment organic matter as food source and very few taxa whose trophic source was constituted by macrophytes. The periphyton was the most important source during all seasons; it produced the longest chain, with three trophic positions. Whatever the season and trophic source, all collected macroinvertebrates contained methyl mercury and the latter was biomagnified in all trophic chains that we identified. The biomagnification of methylmercury through invertebrate trophic chains accurately reflected the existence and length of these chains. Biomagnification was virtually non-existent in the sediment-based chain, low and restricted to the dry season in the macrophyte-based chain. It was significant in the seston-based chain, but limited by the existence of only two trophic levels and restricted to the wet season. Finally, it was very effective in the periphyton-based chain, which offers the highest rate of contamination of the source but, above all, the largest number of trophic levels.

Transfer of mercury and methylmercury along macroinvertebrate food chains in a floodplain lake of the Beni River, Bolivian Amazonia

Energy Technology Data Exchange (ETDEWEB)

Molina, Carlos Israel, E-mail: camoar6088@gmail.com [Instituto de Ecologia, Unidad de Limnologia, UMSA, Casilla postal 10077, La Paz (Bolivia, Plurinational State of); Institut de Recherche pour le Developpement IRD, Casilla postal 9214, La Paz (Bolivia, Plurinational State of); CONICET-Facultad de Ciencias Naturales, Universidad Nacional de Tucuman, Miguel Lillo 205, 4 000, Tucuman (Argentina); Gibon, Francois-Marie [Institut de Recherche pour le Developpement IRD, Casilla postal 9214, La Paz (Bolivia, Plurinational State of); IRD, UMR BOREA, Museum national d' Histoire Naturelle MNHN, Case postale 26, 75231, Paris cedex 05 (France); Duprey, Jean-Louis [Institut de Recherche pour le Developpement IRD, Casilla postal 9214, La Paz (Bolivia, Plurinational State of); Dominguez, Eduardo [CONICET-Facultad de Ciencias Naturales, Universidad Nacional de Tucuman, Miguel Lillo 205, 4 000, Tucuman (Argentina); Guimaraes, Jean-Remy D. [Instituto de Biofisica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Bloco G-CCS, Rio de Janeiro, CEP 21949-900 (Brazil); Roulet, Marc [Institut de Recherche pour le Developpement IRD, Casilla postal 9214, La Paz (Bolivia, Plurinational State of)

2010-07-15

We have evaluated the mercury and methylmercury transfers to and within the macroinvertebrate communities of a floodplain lake of the Beni River basin, Bolivia, during three hydrological seasons and in two habitats (open water and vegetation belt). Using the stable isotopes {delta}{sup 13}C and {delta}{sup 15}N, six trophic chains were identified during a previous study. Four are based on only one source: seston, organic matter from the bottom sediment, periphyton and macrophytes. Two are based on mixed sources (seston and periphyton in one case, periphyton and macrophytes in the other). During sampling, we found only one taxon that had surface sediment organic matter as food source and very few taxa whose trophic source was constituted by macrophytes. The periphyton was the most important source during all seasons; it produced the longest chain, with three trophic positions. Whatever the season and trophic source, all collected macroinvertebrates contained methyl mercury and the latter was biomagnified in all trophic chains that we identified. The biomagnification of methylmercury through invertebrate trophic chains accurately reflected the existence and length of these chains. Biomagnification was virtually non-existent in the sediment-based chain, low and restricted to the dry season in the macrophyte-based chain. It was significant in the seston-based chain, but limited by the existence of only two trophic levels and restricted to the wet season. Finally, it was very effective in the periphyton-based chain, which offers the highest rate of contamination of the source but, above all, the largest number of trophic levels.

Combined effects of hydrologic alteration and cyprinid fish in mediating biogeochemical processes in a Mediterranean stream.

Science.gov (United States)

Rubio-Gracia, Francesc; Almeida, David; Bonet, Berta; Casals, Frederic; Espinosa, Carmen; Flecker, Alexander S; García-Berthou, Emili; Martí, Eugènia; Tuulaikhuu, Baigal-Amar; Vila-Gispert, Anna; Zamora, Lluis; Guasch, Helena

2017-12-01

Flow regimes are important drivers of both stream community and biogeochemical processes. However, the interplay between community and biogeochemical responses under different flow regimes in streams is less understood. In this study, we investigated the structural and functional responses of periphyton and macroinvertebrates to different densities of the Mediterranean barbel (Barbus meridionalis, Cyprinidae) in two stream reaches differing in flow regime. The study was conducted in Llémena Stream, a small calcareous Mediterranean stream with high nutrient levels. We selected a reach with permanent flow (permanent reach) and another subjected to flow regulation (regulated reach) with periods of flow intermittency. At each reach, we used in situ cages to generate 3 levels of fish density. Cages with 10 barbels were used to simulate high fish density (>7indm -2 ); cages with open sides were used as controls (i.e. exposed to actual fish densities of each stream reach) thus having low fish density; and those with no fish were used to simulate the disappearance of fish that occurs with stream drying. Differences in fish density did not cause significant changes in periphyton biomass and macroinvertebrate density. However, phosphate uptake by periphyton was enhanced in treatments lacking fish in the regulated reach with intermittent flow but not in the permanent reach, suggesting that hydrologic alteration hampers the ability of biotic communities to compensate for the absence of fish. This study indicates that fish density can mediate the effects of anthropogenic alterations such as flow intermittence derived from hydrologic regulation on stream benthic communities and associated biogeochemical processes, at least in eutrophic streams. Copyright © 2017. Published by Elsevier B.V.

Investigation of road salts and biotic stressors on freshwater wetland communities.

Science.gov (United States)

Jones, Devin K; Mattes, Brian M; Hintz, William D; Schuler, Matthew S; Stoler, Aaron B; Lind, Lovisa A; Cooper, Reilly O; Relyea, Rick A

2017-02-01

The application of road deicing salts has led to the salinization of freshwater ecosystems in northern regions worldwide. Increased chloride concentrations in lakes, streams, ponds, and wetlands may negatively affect freshwater biota, potentially threatening ecosystem services. In an effort to reduce the effects of road salt, operators have increased the use of salt alternatives, yet we lack an understanding of how these deicers affect aquatic communities. We examined the direct and indirect effects of the most commonly used road salt (NaCl) and a proprietary salt mixture (NaCl, KCl, MgCl 2 ), at three environmentally relevant concentrations (150, 470, and 780 mg Cl - /L) on freshwater wetland communities in combination with one of three biotic stressors (control, predator cues, and competitors). The communities contained periphyton, phytoplankton, zooplankton, and two tadpole species (American toads, Anaxyrus americanus; wood frogs, Lithobates sylvaticus). Overall, we found the two road salts did not interact with the natural stressors. Both salts decreased pH and reduced zooplankton abundance. The strong decrease in zooplankton abundance in the highest NaCl concentration caused a trophic cascade that resulted in increased phytoplankton abundance. The highest NaCl concentration also reduced toad activity. For the biotic stressors, predatory stress decreased whereas competitive stress increased the activity of both tadpole species. Wood frog survival, time to metamorphosis, and mass at metamorphosis all decreased under competitive stress whereas toad time to metamorphosis increased and mass at metamorphosis decreased. Road salts and biotic stressors can both affect freshwater communities, but their effects are not interactive. Copyright © 2016 Elsevier Ltd. All rights reserved.

Characterization of habitats based on algal periphyton biomass in the upper Paraná River floodplain, Brazil Mudanças na biomassa de algas perifíticas na planície de inundação do alto Rio Paraná, Brasil

Directory of Open Access Journals (Sweden)

JA. Leandrini

2008-08-01

Full Text Available Considering the relevant role played by the hydrological regime on the structure and functioning of floodplains, this study aims at characterizing different types of aquatic environments according to periphyton biomass and evaluating the influence of the fluviometric levels of the Paraná River and other forcing functions upon the periphytic community. Periphyton (chlorophyll a was analyzed in 28 habitats, during the years 2000 and 2001, in high and low water seasons. Both years were characterized by lacking the characteristic high water season. The Principal Components Analysis revealed two groups. The first component was positively associated with hydrometric level, electric conductivity, pH and transparency, and negatively with total nitrogen and total phosphorus, dissolved organic carbon and turbidity. The second component separated the habitats of Paraná River in the period of low waters from other environments, mainly for hydrometric level and high transparency values. Periphytic biomass of the habitats demonstrated that the maintenance of the functional integrity of the Upper Paraná River floodplain is closely related to its hydrologic cycle.Tendo como princípio que o regime hidrológico é a principal função de força em planícies de inundação, este trabalho visa caracterizar diferentes ambientes através da biomassa da comunidade perifítica e relacionar a influência do nível hidrométrico sobre esta comunidade. Para isso, a biomassa perifítica (clorofila a foi analisada em 28 habitats, sendo amostrados dois anos, 2000 e 2001, em diferentes períodos, águas altas e águas baixas. Na Análise de Componentes Principais, foram evidenciados dois grupos. O primeiro componente associado positivamente com o nível hidrométrico, condutividade elétrica, pH e transparência e, negativamente, com nitrogênio e fósforo total, carbono orgânico dissolvido e turbidez. O segundo componente separou os ambientes pertencentes ao rio Paran

Use of algae for monitoring of heavy metals in the River Vardar, Macedonia

Directory of Open Access Journals (Sweden)

Z. LEVKOV

2002-06-01

Full Text Available Aiming to resolve some of the problems regarding monitoring of heavy metals in rivers using Cladophora glomerata and epilithic algal communities, a year’s survey of Co, Cd, Cu, Fe, Mn, Pb and Zn has been conducted on the river Vardar, FY Republic of Macedonia. Obtained results and statistical analysis clearly point out the well documented possibility of using epilithon (basically diatom communities as a monitoring tool, since correlation patterns for epilithon are either better or the same as those for Cladophora, while at the same time epilithon is much more reliable for monitoring, especially in cases when no other plant material can be obtained.

Stressor-Response Models Relating Nutrient Enrichment to Algal Communities in Pacific Northwest Streams and Rivers

Science.gov (United States)

Sobota, D. J.; Hubler, S.; Paul, M. J.; Labiosa, R.

2015-12-01

Excessive algal growth in streams and rivers from nutrient enrichment can cause costly human health and environmental problems. As part of the US Environmental Protection Agency's Nutrient Scientific Technical Exchange Partnership and Support (N-STEPS) program, we have been developing stressor-response (S-R) models relating nutrients to attached algal (periphyton) communities to help prioritize monitoring for water quality impairments in Oregon (Pacific Northwest, USA) streams and rivers. Existing data from the state and neighboring states were compiled and standardized from the Oregon Department of Environmental Quality, US Environmental Protection Agency, and the US Geological Survey. To develop S-R models, algal community and biomass metrics were compared with nitrogen (N) and phosphorus (P) concentration data, including total, dissolved, and inorganic forms of these nutrients. In total, 928 paired algal-nutrient samples were compiled from the 8 Level-III Ecoregions occurring in Oregon. Relationships between algal biomass metrics and nutrient concentrations were weak, with only ash-free dry mass and standing stock of chlorophyll a showing slight positive relationships across gradients of total N and soluble reactive P concentrations, respectively. In contrast, metrics describing algal community composition, including percent diatoms and abundance of nutrient-sensitive species, showed very strong nonlinear relationships with total N or P concentrations. This suggests that data describing algal community composition can help identify specific nutrient stressors across environmentally-diverse streams and rivers in the Pacific Northwest. Future analyses will examine if nutrient-algal S-R models vary across different hydrological, physiographical, and ecological settings in the region.

Profile of microbial communities on carbonate stones of the medieval church of San Leonardo di Siponto (Italy) by Illumina-based deep sequencing.

Science.gov (United States)

Chimienti, Guglielmina; Piredda, Roberta; Pepe, Gabriella; van der Werf, Inez Dorothé; Sabbatini, Luigia; Crecchio, Carmine; Ricciuti, Patrizia; D'Erchia, Anna Maria; Manzari, Caterina; Pesole, Graziano

2016-10-01

Comprehensive studies of the biodiversity of the microbial epilithic community on monuments may provide critical insights for clarifying factors involved in the colonization processes. We carried out a high-throughput investigation of the communities colonizing the medieval church of San Leonardo di Siponto (Italy) by Illumina-based deep sequencing. The metagenomic analysis of sequences revealed the presence of Archaea, Bacteria, and Eukarya. Bacteria were Actinobacteria, Proteobacteria, Bacteroidetes, Cyanobacteria, Chloroflexi, Firmicutes and Candidatus Saccharibacteria. The predominant phylum was Actinobacteria, with the orders Actynomycetales and Rubrobacteriales, represented by the genera Pseudokineococcus, Sporichthya, Blastococcus, Arthrobacter, Geodermatophilus, Friedmanniella, Modestobacter, and Rubrobacter, respectively. Cyanobacteria sequences showing strong similarity with an uncultured bacterium sequence were identified. The presence of the green algae Oocystaceae and Trebuxiaceae was revealed. The microbial diversity was explored at qualitative and quantitative levels, evaluating the richness (the number of operational taxonomic units (OTUs)) and the abundance of reads associated with each OTU. The rarefaction curves approached saturation, suggesting that the majority of OTUs were recovered. The results highlighted a structured community, showing low diversity, made up of extremophile organisms adapted to desiccation and UV radiation. Notably, the microbiome appeared to be composed not only of microorganisms possibly involved in biodeterioration but also of carbonatogenic bacteria, such as those belonging to the genus Arthrobacter, which could be useful in bioconservation. Our investigation demonstrated that molecular tools, and in particular the easy-to-run next-generation sequencing, are powerful to perform a microbiological diagnosis in order to plan restoration and protection strategies.

Algal and water-quality data for Rapid Creek and Canyon Lake near Rapid City, South Dakota, 2007

Science.gov (United States)

Hoogestraat, Galen K.; Putnam, Larry D.; Graham, Jennifer L.

2008-01-01

This report summarizes the results of algae and water-quality sampling on Rapid Creek and Canyon Lake during May and September 2007. The overall purpose of the study was to determine the algal community composition of Rapid Creek and Canyon Lake in relation to organisms that are known producers of unwanted tastes and odors in drinking-water supplies. Algal assemblage structure (phytoplankton and periphyton) was examined at 16 sites on Rapid Creek and Canyon Lake during May and September 2007, and actinomycetes bacteria were sampled at the Rapid City water treatment plant intake in May 2007, to determine if taste-and-odor producing organisms were present. During the May 2007 sampling, 3 Rapid Creek sites and 4 Canyon Lake sites were quantitatively sampled for phytoplankton in the water column, 7 Rapid Creek sites were quantitatively sampled for attached periphyton, and 4 lake and retention pond sites were qualitatively sampled for periphyton. Five Rapid Creek sites were sampled for geosmin and 2-methylisoborneol, two common taste-and-odor causing compounds known to affect water supplies. During the September 2007 sampling, 4 Rapid Creek sites were quantitatively sampled for attached periphyton, and 3 Canyon Lake sites were qualitatively sampled for periphyton. Water temperature, dissolved oxygen, pH, and specific conductance were measured during each sampling event. Methods of collection and sample analysis are presented for the various types of biological and chemical constituent samples. Diatoms comprised 91-100 percent of the total algal biovolume in periphyton samples collected during May and September. Cyanobacteria (also called blue-green algae) were detected in 7 of the 11 quantitative periphyton samples and ranged from 0.01 to 2.0 percent of the total biovolume. Cyanobacteria were present in 3 of the 7 phytoplankton samples collected in May, but the relative biovolumes were small (0.01-0.2 percent). Six of seven qualitative samples collected from Canyon Lake

Influence of a chlor-alkali superfund site on mercury bioaccumulation in periphyton and low-trophic level fauna

Science.gov (United States)

Buckman, Kate L.; Marvin-DiPasquale, Mark C.; Taylor, Vivien F.; Chalmers, Ann T.; Broadley, Hannah J.; Agee, Jennifer L.; Jackson, Brian P.; Chen, Celia Y.

2015-01-01

In Berlin, New Hampshire, USA, the Androscoggin River flows adjacent to a former chlor-alkali facility that is a US Environmental Protection Agency Superfund site and source of mercury (Hg) to the river. The present study was conducted to determine the fate and bioaccumulation of methylmercury (MeHg) to lower trophic-level taxa in the river. Surface sediment directly adjacent to the source showed significantly elevated MeHg (10–40× increase, mean ± standard deviation [SD]: 20.1 ± 24.8 ng g–1 dry wt) and total mercury (THg; 10–30× increase, mean ± SD: 2045 ± 2669 ng g–1 dry wt) compared with all other reaches, with sediment THg and MeHg from downstream reaches elevated (3–7× on average) relative to the reference (THg mean ± SD: 33.5 ± 9.33 ng g–1 dry wt; MeHg mean ± SD: 0.52 ± 0.21 ng g–1 dry wt). Water column THg concentrations adjacent to the point source for both particulate (0.23 ng L–1) and dissolved (0.76 ng L–1) fractions were 5-fold higher than at the reference sites, and 2-fold to 5-fold higher than downstream. Methylmercury production potential of periphyton material was highest (2–9 ng g–1 d–1 dry wt) adjacent to the Superfund site; other reaches were close to or below reporting limits (0. 1 ng g–1 d–1 dry wt). Total Hg and MeHg bioaccumulation in fauna was variable across sites and taxa, with no clear spatial patterns downstream of the contamination source. Crayfish, mayflies, and shiners showed a weak positive relationship with porewater MeHg concentration.

The Genus Cladophora Kützing (Ulvophyceae) as a Globally Distributed Ecological Engineer.

Science.gov (United States)

Zulkifly, Shahrizim B; Graham, James M; Young, Erica B; Mayer, Robert J; Piotrowski, Michael J; Smith, Izak; Graham, Linda E

2013-02-01

The green algal genus Cladophora forms conspicuous nearshore populations in marine and freshwaters worldwide, commonly dominating peri-phyton communities. As the result of human activities, including the nutrient pollution of nearshore waters, Cladophora-dominated periphyton can form nuisance blooms. On the other hand, Cladophora has ecological functions that are beneficial, but less well appreciated. For example, Cladophora has previously been characterized as an ecological engineer because its complex structure fosters functional and taxonomic diversity of benthic microfauna. Here, we review classic and recent literature concerning taxonomy, cell biology, morphology, reproductive biology, and ecology of the genus Cladophora, to examine how this alga functions to modify habitats and influence littoral biogeochemistry. We review the evidence that Cladophora supports large, diverse populations of microalgal and bacterial epiphytes that influence the cycling of carbon and other key elements, and that the high production of cellulose and hydrocarbons by Cladophora-dominated periphyton has the potential for diverse technological applications, including wastewater remediation coupled to renewable biofuel production. We postulate that well-known aspects of Cladophora morphology, hydrodynamically stable and perennial holdfasts, distinctively branched architecture, unusually large cell and sporangial size and robust cell wall construction, are major factors contributing to the multiple roles of this organism as an ecological engineer. © 2013 Phycological Society of America.

Direct and indirect effects of copper-contaminated sediments on the functions of model freshwater ecosystems.

Science.gov (United States)

Gardham, Stephanie; Chariton, Anthony A; Hose, Grant C

2015-01-01

Copper is acutely toxic to, and directly affects, primary producers and decomposers, which are key players in essential processes such as the nutrient cycle in freshwater ecosystems. Even though the indirect effects of metals (for example effects due to changes in species interactions) may be more common than direct effects, little is known about the indirect effects of copper on primary producers and decomposers. The effects of copper on phytoplankton, macrophytes, periphyton and organic matter decomposition in an outdoor lentic mesocosm facility were assessed, and links between the responses examined. Copper directly decreased macrophyte growth, subsurface organic matter decomposition, and the potential for high phytoplankton Chlorophyll a concentrations. However, periphyton cover and organic matter decomposition on the surface of the sediment were stimulated by the presence of copper. These latter responses were attributed to indirect effects, due to a reduction in grazing pressure from snails, particularly Physa acuta, in the higher copper-contaminated mesocosms. This permitted the growth of periphyton and other heterotrophs, ultimately increasing decomposition at the sediment surface. The present study demonstrates the pronounced influence indirect effects may have on ecological function, findings that may not be observed in traditional laboratory studies (which utilize single species or simplistic communities).

Tissue N content and 15N natural abundance in epilithic mosses for indicating atmospheric N deposition in the Guiyang area, SW China

International Nuclear Information System (INIS)

Liu Xueyan; Xiao Huayun; Liu Congqiang; Li Youyi; Xiao Hongwei

2008-01-01

Tissue N contents and δ 15 N signatures in 175 epilithic mosses were investigated from urban to rural sites in Guiyang (SW China) to determine atmospheric N deposition. Moss N contents (0.85-2.97%) showed a significant decrease from the urban area (mean = 2.24 ± 0.32%, 0-5 km) to the rural area (mean = 1.27 ± 0.13%, 20-25 km), indicating that the level of N deposition decreased away from the urban environment, while slightly higher N contents re-occurred at sites beyond 30 km, suggesting higher N deposition in more remote rural areas. Moss δ 15 N ranged from -12.50 per mille to -1.39 per mille and showed a clear bimodal distribution (-12 per mille to -6 per mille and -5 per mille to -2 per mille ), suggesting that there are two main sources for N deposition in the Guiyang area. More negative δ 15 N (mean = -8.87 ± 1.65 per mille ) of urban mosses mainly indicated NH 3 released from excretory wastes and sewage, while the less negative δ 15 N (from -3.83 ± 0.82 per mille to -2.48 ± 0.95 per mille ) of rural mosses were mainly influenced by agricultural NH 3 . With more negative values in the urban area than in the rural area, the pattern of moss δ 15 N variation in Guiyang was found to be opposite to cities where N deposition is dominated by NO x -N. Therefore, NH x -N is the dominant N form deposited in the Guiyang area, which is supported by higher NH x -N than NO x -N in local atmospheric deposition. From the data showing that moss is responding to NH x -N/NO x -N in deposition it can be further demonstrated that the variation of moss δ 15 N from the Guiyang urban to rural area was more likely controlled by the ratio of urban-NH x /agriculture-NH x than the ratio of NH x -N/NO x -N. The results of this study have extended knowledge of atmospheric N sources in city areas, showing that urban sewage discharge could be important in cities co-generic to Guiyang

Epipsammic diatoms in streams influenced by urban pollution, São Carlos, SP, Brazil

Directory of Open Access Journals (Sweden)

T. Bere

Full Text Available Epipsammic diatoms have important implications for ecosystem processes in lotic environments. Most of the studies on benthic diatoms concentrate on epilithic diatoms and very little is known about epipsammic diatoms. The objective of this study was to assess epipsammic diatom communities in streams in relation to environmental conditions. Epipsammic diatoms and water quality sampling was done at 7 sites during summer base flow period (2008. Forward stepwise multiple regression and canonical correspondence analysis (CCA were used to determine environmental gradients along which species vary with physical and chemical variables. A total of 112 diatom species distributed among 44 genera were recorded. Altitude and the process of eutrophication played a significant role in structuring diatom communities in the study region.

Shallow water marine sediment bacterial community shifts along a natural CO2 gradient in the Mediterranean Sea off Vulcano, Italy.

Science.gov (United States)

Kerfahi, Dorsaf; Hall-Spencer, Jason M; Tripathi, Binu M; Milazzo, Marco; Lee, Junghoon; Adams, Jonathan M

2014-05-01

The effects of increasing atmospheric CO(2) on ocean ecosystems are a major environmental concern, as rapid shoaling of the carbonate saturation horizon is exposing vast areas of marine sediments to corrosive waters worldwide. Natural CO(2) gradients off Vulcano, Italy, have revealed profound ecosystem changes along rocky shore habitats as carbonate saturation levels decrease, but no investigations have yet been made of the sedimentary habitat. Here, we sampled the upper 2 cm of volcanic sand in three zones, ambient (median pCO(2) 419 μatm, minimum Ω(arag) 3.77), moderately CO(2)-enriched (median pCO(2) 592 μatm, minimum Ω(arag) 2.96), and highly CO(2)-enriched (median pCO(2) 1611 μatm, minimum Ω(arag) 0.35). We tested the hypothesis that increasing levels of seawater pCO(2) would cause significant shifts in sediment bacterial community composition, as shown recently in epilithic biofilms at the study site. In this study, 454 pyrosequencing of the V1 to V3 region of the 16S rRNA gene revealed a shift in community composition with increasing pCO(2). The relative abundances of most of the dominant genera were unaffected by the pCO(2) gradient, although there were significant differences for some 5 % of the genera present (viz. Georgenia, Lutibacter, Photobacterium, Acinetobacter, and Paenibacillus), and Shannon Diversity was greatest in sediments subject to long-term acidification (>100 years). Overall, this supports the view that globally increased ocean pCO(2) will be associated with changes in sediment bacterial community composition but that most of these organisms are resilient. However, further work is required to assess whether these results apply to other types of coastal sediments and whether the changes in relative abundance of bacterial taxa that we observed can significantly alter the biogeochemical functions of marine sediments.

Nitrogen Processing Efficiency of an Upper Mississippi River Backwater Lake

Science.gov (United States)

2006-08-01

with denitrification accounting for ~32 percent. By subtraction, assimilation (bacteria, periphyton , phytoplankton , and macrophyte uptake) must...later release and processing or transport. Phytoplankton and periphyton can assimilate considerable nitrate for growth in the absence of ammonia in...over the relatively short period of this study. As with phytoplankton and periphyton biomass, the macrophyte N pool is subject to N transformation

If you see one, have you seen them all?: Community-wide effects of insecticide cross-resistance in zooplankton populations near and far from agriculture.

Science.gov (United States)

Bendis, Randall J; Relyea, Rick A

2016-08-01

The worldwide use of pesticides has led to increases in agricultural yields by reducing crop losses. However, increased pesticide use has resulted in pesticide-resistant pest species and recent studies have discovered pesticide-resistance in non-target species living close to farms. Such increased tolerance not only affects the species, but can alter the entire food web. Given that some species can evolve not only resistance to a single pesticide, but also cross-resistance to other pesticides that share the same mode of action, one would predict that cross-resistance to pesticides would also have effects on the entire community and affect community stability. To address this hypothesis, we conducted an outdoor mesocosm experiment comprised of 200 identical aquatic communities with phytoplankton, periphyton, and leopard frog (Lithobates pipiens) tadpoles. To these communities, we added one of four Daphnia pulex populations that we previously discovered were either resistant or sensitive to the insecticide of chlorpyrifos as a result of living close to or far from agriculture, respectively. We then exposed the communities to either no insecticide or three different concentrations of AChE-inhibiting insecticides (chlorpyrifos, malathion or carbaryl) or sodium channel-inhibiting insecticides (permethrin or cypermethrin). We discovered that communities containing sensitive Daphnia pulex experienced phytoplankton blooms and subsequent cascades through all trophic groups including amphibians at moderate to high concentrations of all five insecticides. However, communities containing resistant D. pulex were buffered from these effects at low to moderate concentrations of all AChE-inhibiting insecticides, but were not buffered against the pyrethroid insecticides. These data suggest that a simple change in the population-level resistance of zooplankton to a single insecticide can have widespread consequences for community stability and that the effects can be extrapolated

Influence of Soils, Riparian Zones, and Hydrology on Nutrients, Herbicides, and Biological Relations in Midwestern Agricultural Streams

Science.gov (United States)

Porter, S.

2001-12-01

Chemical, biological, and habitat conditions were characterized in 70 streams in the upper Mississippi River basin during August 1997, as part of the U.S. Geological Survey's National Water-Quality Assessment (NAWQA) Program. The study was designed to evaluate algal and macroinvertebrate responses to high agricultural intensity in relation to nonpoint sources of nutrients and herbicides, characteristics of basin soils, wooded-riparian vegetation, and hydrology. Concentrations and forms of nutrients, herbicides and their metabolites, and seston constituents varied significantly with regional differences in soil properties, ground and surface water relations, density of riparian trees, and precedent rainfall-runoff conditions. Dissolved nitrate concentrations were relatively low in streams with high algal productivity; however, nitrate concentrations increased with basin water yield, which was associated with the regional distribution of rainfall during the month prior to the study. Stream productivity and respiration were positively correlated with seston (phytoplankton) chlorophyll concentrations, which were significantly larger in streams in areas with poorly drained soils and low riparian-tree density. Concentrations of dissolved phosphorus were low in streams where periphyton biomass was high. Periphyton biomass was relatively larger in streams with clear water and low abundance of macroinvertebrates that consume algae. Periphyton biomass decreased rapidly with modest increases in the abundance of scrapers such as snails and certain mayfly taxa. Differences in dissolved oxygen, organic carbon, stream velocity, and precedent hydrologic conditions explained much of the variance in macroinvertebrate community structure. The overall number of macroinvertebrate species and number of mayfly, caddisfly, and stonefly (EPT) taxa that are sensitive to organic enrichment were largest in streams with moderate periphyton biomass, in areas with moderately-well drained soils

Aquatic studies at the 100-HR-3 and 100-NR-1 operable units

International Nuclear Information System (INIS)

Cushing, C.E.

1993-04-01

Pacific Northwest Laboratory initiated a program to characterize selected aquatic biological populations to determine (1) existing levels of inorganic chemical and radionuclide contamination, and (2) the populations' suitability as indicators of chemical releases during cleanup activities at the US Department of Energy's Hanford Site. Following work plans for the ground-water operable units, lower trophic levels in the aquatic habitat (periphyton and caddisfly larvae) were evaluated for contaminants at the 100-HR-3 Operable Unit and 100-NR-1 Operable Unit. The results were evaluated to determine the need for further sampling. If the results showed no significant contamination compared to upriver levels, sampling would be discontinued. The periphyton community appears to be suitable for determining contamination levels. Baseline concentrations for stable chromium were established and will be useful for comparing samples collected when contaminant release is expected. Concentrations of 60 Co, 90 Sr, and 137 Cs in periphyton were essentially below detectable limits, which will also make this community useful in detecting potential releases of radionuclides during cleanup activities. Levels for both stable chromium and radionuclides were essentially below detection limits for caddisfly larvae. Thus, these organisms may be used to monitor suspected contaminant releases from cleanup activities; if concentrations exceed detection limits, they may be related to these activities. Two candidate threatened and endangered species of molluscs occur in the Hanford Reach of the Columbia River. These are the shortface lanx (Fisherola nuttalli), which is a Washington State candidate species, and the Columbia pebblesnail (Fluminicola columbiana), which is both a state and federal candidate species. Specimens of the shortface lanx were observed in the vicinity of N Springs (100-NR-1 Operable Unit); they likely occur throughout this area

Water quality and algal conditions in the North Umpqua River, Oregon, 1995-2007, and their response to Diamond Lake restoration

Science.gov (United States)

Carpenter, Kurt D.; Anderson, Chauncey W.; Jones, Mikeal E.

2014-01-01

The Wild and Scenic North Umpqua River is one of the highest-quality waters in the State of Oregon, supporting runs of wild salmon, steelhead, and trout. For many years, blooms of potentially toxic blue-green algae in Diamond and Lemolo Lakes have threatened water quality, fisheries, and public health. The blooms consist primarily of Anabaena, a nitrogen (N)-fixing planktonic alga that appears to have contributed to N enrichment, which could account for changes in communities and biomass of periphyton, or attached benthic algae, in the river. Periphyton can become a nuisance in summer by affecting riffle habitat and causing high pH that fails to meet State of Oregon water-quality standards. These symptoms of nutrient enrichment in the North Umpqua River were first documented in 1995, and the symptoms have continued since then. Restoring natural ecosystem processes that store nutrients rather than fueling algae might help improve pH and water-clarity conditions.

The Mass-Dimension Relationships in the Mussels Mytilus Galloprovincialis (Mollusca, Bivalvia from Different Phenotypical Groups in Periphyton Populations near Odessa Coast, the North-Western Part of Black Sea

Directory of Open Access Journals (Sweden)

Govorin I. A.

2016-06-01

Full Text Available The data of the size-mass indices in the mussels Mytilus galloprovincialis (Lamarck, 1819 from three phenotypic groups - brown, dark violet (black and “zebra” (brown with radial black stripes shells in the periphyton settlements on the concrete traverses near Odessa coast, the North-western part of Black Sea (Ukraine, in March-November 2014-2015 are presented. A comparative evaluation has been made on the relationships of total mass of the mollusks, wet and dry mass of their soft body and mass of the shells on the one hand, and the size of animals (length of its shells on the other hand, in the each of phenotypical groups from the five marine beach areas. It is shown, that in the marine areas with different degrees of isolation from the open sea by coast-protection engineering constructions, the mussels from different phenotypes have almost the same size-mass characteristics. Only the dry weight of soft animal body, which indicated to fatness of mollusk and therefore demonstrated his biological prosperity in specific hydrological conditions, can serve as a reliable criterion which can mark the shellfish habitats with different gradients of environmental factors.

Distribution of total and methylmercury in different ecosystem compartments in the Everglades: Implications for mercury bioaccumulation

International Nuclear Information System (INIS)

Liu Guangliang; Cai Yong; Philippi, Thomas; Kalla, Peter; Scheidt, Daniel; Richards, Jennifer; Scinto, Leonard; Appleby, Charlie

2008-01-01

We analyzed Hg species distribution patterns among ecosystem compartments in the Everglades at the landscape level in order to explore the implications of Hg distribution for Hg bioaccumulation and to investigate major biogeochemical processes that are pertinent to the observed Hg distribution patterns. At an Everglade-wide scale, THg concentrations were significantly increased in the following order: periphyton < flocculent material (floc) < soil, while relatively high MeHg concentrations were observed in floc and periphyton. Differences in the methylation potential, THg concentration, and MeHg retention capacity could explain the relatively high MeHg concentrations in floc and periphyton. The MeHg/THg ratio was higher for water than for soil, floc, or periphyton probably due to high dissolved organic carbon (DOC) concentrations present in the Everglades. Mosquitofish THg positively correlated with periphyton MeHg and DOC-normalized water MeHg. The relative THg and MeHg distribution patterns among ecosystem compartments favor Hg bioaccumulation in the Everglades. - Mercury bioaccumulation in Florida Everglades is related to the distribution patterns of mercury species among ecosystem compartments

Distribution of total and methylmercury in different ecosystem compartments in the Everglades: Implications for mercury bioaccumulation

Energy Technology Data Exchange (ETDEWEB)

Liu Guangliang [Department of Chemistry and Biochemistry, Florida International University, 11200 SW 8th Street, Miami, FL 33199 (United States); Southeast Environmental Research Center, Florida International University, Miami, FL 33199 (United States); Cai Yong [Department of Chemistry and Biochemistry, Florida International University, 11200 SW 8th Street, Miami, FL 33199 (United States); Southeast Environmental Research Center, Florida International University, Miami, FL 33199 (United States)], E-mail: cai@fiu.edu; Philippi, Thomas [Department of Biological Sciences, Florida International University, Miami, FL 33199 (United States); Kalla, Peter; Scheidt, Daniel [US Environmental Protection Agency, Region 4, Science and Ecosystem Support Division, Athens, GA 30605 (United States); Richards, Jennifer [Department of Biological Sciences, Florida International University, Miami, FL 33199 (United States); Scinto, Leonard [Southeast Environmental Research Center, Florida International University, Miami, FL 33199 (United States); Appleby, Charlie [US Environmental Protection Agency, Region 4, Science and Ecosystem Support Division, Athens, GA 30605 (United States)

2008-05-15

We analyzed Hg species distribution patterns among ecosystem compartments in the Everglades at the landscape level in order to explore the implications of Hg distribution for Hg bioaccumulation and to investigate major biogeochemical processes that are pertinent to the observed Hg distribution patterns. At an Everglade-wide scale, THg concentrations were significantly increased in the following order: periphyton < flocculent material (floc) < soil, while relatively high MeHg concentrations were observed in floc and periphyton. Differences in the methylation potential, THg concentration, and MeHg retention capacity could explain the relatively high MeHg concentrations in floc and periphyton. The MeHg/THg ratio was higher for water than for soil, floc, or periphyton probably due to high dissolved organic carbon (DOC) concentrations present in the Everglades. Mosquitofish THg positively correlated with periphyton MeHg and DOC-normalized water MeHg. The relative THg and MeHg distribution patterns among ecosystem compartments favor Hg bioaccumulation in the Everglades. - Mercury bioaccumulation in Florida Everglades is related to the distribution patterns of mercury species among ecosystem compartments.

Tissue N content and {sup 15}N natural abundance in epilithic mosses for indicating atmospheric N deposition in the Guiyang area, SW China

Energy Technology Data Exchange (ETDEWEB)

Liu Xueyan [State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002 (China); Graduate University of the Chinese Academy of Sciences, Beijing 100049 (China)], E-mail: liuxueyan@vip.skleg.cn; Xiao Huayun [State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002 (China)], E-mail: xiaohuayun@vip.skleg.cn; Liu Congqiang [State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002 (China); Li Youyi; Xiao Hongwei [State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002 (China); Graduate University of the Chinese Academy of Sciences, Beijing 100049 (China)

2008-09-15

Tissue N contents and {delta}{sup 15}N signatures in 175 epilithic mosses were investigated from urban to rural sites in Guiyang (SW China) to determine atmospheric N deposition. Moss N contents (0.85-2.97%) showed a significant decrease from the urban area (mean = 2.24 {+-} 0.32%, 0-5 km) to the rural area (mean = 1.27 {+-} 0.13%, 20-25 km), indicating that the level of N deposition decreased away from the urban environment, while slightly higher N contents re-occurred at sites beyond 30 km, suggesting higher N deposition in more remote rural areas. Moss {delta}{sup 15}N ranged from -12.50 per mille to -1.39 per mille and showed a clear bimodal distribution (-12 per mille to -6 per mille and -5 per mille to -2 per mille ), suggesting that there are two main sources for N deposition in the Guiyang area. More negative {delta}{sup 15}N (mean = -8.87 {+-} 1.65 per mille ) of urban mosses mainly indicated NH{sub 3} released from excretory wastes and sewage, while the less negative {delta}{sup 15}N (from -3.83 {+-} 0.82 per mille to -2.48 {+-} 0.95 per mille ) of rural mosses were mainly influenced by agricultural NH{sub 3}. With more negative values in the urban area than in the rural area, the pattern of moss {delta}{sup 15}N variation in Guiyang was found to be opposite to cities where N deposition is dominated by NO{sub x}-N. Therefore, NH{sub x}-N is the dominant N form deposited in the Guiyang area, which is supported by higher NH{sub x}-N than NO{sub x}-N in local atmospheric deposition. From the data showing that moss is responding to NH{sub x}-N/NO{sub x}-N in deposition it can be further demonstrated that the variation of moss {delta}{sup 15}N from the Guiyang urban to rural area was more likely controlled by the ratio of urban-NH{sub x}/agriculture-NH{sub x} than the ratio of NH{sub x}-N/NO{sub x}-N. The results of this study have extended knowledge of atmospheric N sources in city areas, showing that urban sewage discharge could be important in cities co

The effects of hydroelectric gates on rivers, hydro-ecological diagnostic and management aid. The Fontauliere example (Ardeche)

International Nuclear Information System (INIS)

Valentin, S.

1996-01-01

Hydropower generation induces artificial fluctuations of flow and thus of hydrodynamic parameters in rivers, downstream of hydroelectric impoundments. On the Fontauliere river (Ardeche basin, France), the ecological effects of two different hydro-peaking regimes were tested and compared to a reference upstream reach. Fish, invertebrate and epilithic communities were surveyed in these reaches. The results enables to classify the factors responsible for the observed effects. The base flow between peaks was the most important for the studied site. When it was too low, aquatic communities were de-structured in comparison with the natural reach. These results enabled to suggest a current velocity threshold to respect in order to determine acceptable base flow for this type of stream. They also enabled to guide for the impact evaluation of hydro-peaking sites. An ecological diagnosis should include the study of the structure and composition of the communities. (author). 22 refs., 2 figs., 4 tabs

Food web architecture and basal resources interact to determine biomass and stoichiometric cascades along a benthic food web.

Directory of Open Access Journals (Sweden)

Rafael D Guariento

Full Text Available Understanding the effects of predators and resources on primary producers has been a major focus of interest in ecology. Within this context, the trophic cascade concept especially concerning the pelagic zone of lakes has been the focus of the majority of these studies. However, littoral food webs could be especially interesting because base trophic levels may be strongly regulated by consumers and prone to be light limited. In this study, the availability of nutrients and light and the presence of an omnivorous fish (Hyphessobrycon bifasciatus were manipulated in enclosures placed in a humic coastal lagoon (Cabiúnas Lagoon, Macaé - RJ to evaluate the individual and interactive effects of resource availability (nutrients and light and food web configuration on the biomass and stoichiometry of periphyton and benthic grazers. Our findings suggest that light and nutrients interact to determine periphyton biomass and stoichiometry, which propagates to the consumer level. We observed a positive effect of the availability of nutrients on periphytic biomass and grazers' biomass, as well as a reduction of periphytic C∶N∶P ratios and an increase of grazers' N and P content. Low light availability constrained the propagation of nutrient effects on periphyton biomass and induced higher periphytic C∶N∶P ratios. The effects of fish presence strongly interacted with resource availability. In general, a positive effect of fish presence was observed for the total biomass of periphyton and grazer's biomass, especially with high resource availability, but the opposite was found for periphytic autotrophic biomass. Fish also had a significant effect on periphyton stoichiometry, but no effect was observed on grazers' stoichiometric ratios. In summary, we observed that the indirect effect of fish predation on periphyton biomass might be dependent on multiple resources and periphyton nutrient stoichiometric variation can affect consumers' stoichiometry.

Effects of bamboo substrate and supplemental feeding on growth and production of hybrid red tilapia fingerlings (Oreochromis mossambicusxOrechromis niloticus)

NARCIS (Netherlands)

Keshavanath, P.; Gangadhar, B.; Ramesh, T.J.; Dam, van A.A.; Beveridge, M.C.M.; Verdegem, M.C.J.

2004-01-01

Periphyton growing on artificial substrates can increase the production of herbivorous fish in aquaculture ponds. Periphyton may be an alternative or a complement for supplemental feed in fingerling production. Growth and production of hybrid red tilapia (Oreochromis mossambicus x Oreochromis

Cesium accumulation by aquatic organisms at different trophic levels following an experimental release into a small reservoir

Energy Technology Data Exchange (ETDEWEB)

Pinder, J.E., E-mail: jepinder@uga.ed [Savannah River Ecology Laboratory, P. O. Drawer E, Aiken, SC 29802 (United States); Hinton, T.G., E-mail: thomas.hinton@irsn.f [Savannah River Ecology Laboratory, P. O. Drawer E, Aiken, SC 29802 (United States); Taylor, B.E., E-mail: TaylorB@dnr.sc.go [Savannah River Ecology Laboratory, P. O. Drawer E, Aiken, SC 29802 (United States); Whicker, F.W., E-mail: ward.whicker@colostate.ed [Department of Environmental and Radiological Health Sciences, Colorado, State University, Fort Collins, CO 80523-1618 (United States)

2011-03-15

The rates of accumulation and subsequent loss of stable cesium ({sup 133}Cs) by organisms at different trophic levels within plankton-based and periphyton-based food chains were measured following the addition of {sup 133}Cs into a small reservoir near Aiken, South Carolina, USA. An uptake parameter u (L kg{sup -1} d{sup -1} dry mass) and a loss rate parameter k (d{sup -1}) were estimated for each organism using time-series measurements of {sup 133}Cs concentrations in water and biota, and these parameters were used to estimate maximum concentrations, times to maximum concentrations, and concentration ratios (C{sub r}). The maximum {sup 133}Cs concentrations for plankton, periphyton, the insect larva Chaoborus punctipennis, which feeds on plankton, and the snail Helisoma trivolvis, which feeds on periphyton, occurred within the first 14 days following the addition, whereas the maximum concentrations for the fish species Lepomis macrochirus and Micropterus salmoides occurred after 170 days. The C{sub r} based on dry mass for plankton and C. punctipennis were 1220 L kg{sup -1} and 5570 L kg{sup -1}, respectively, and were less than the C{sub r} of 8630 L kg{sup -1} for periphyton and 47,700 L kg{sup -1} for H. trivolvis. Although the C{sub r} differed between plankton-based and periphyton-based food chains, they displayed similar levels of biomagnification. Biomagnification was also indicated for fish where the C{sub r} for the mostly nonpiscivorous L. macrochirus of 22,600 L kg{sup -1} was three times less than that for mostly piscivorous M. salmoides of 71,500 L kg{sup -1}. Although the C{sub r} for M. salmoides was greater than those for periphyton and H. trivolvis, the maximum {sup 133}Cs concentrations for periphyton and H. trivolvis were greater than that for M. salmoides. - Research highlights: {yields} A simple uptake and loss model described the Cs dynamics in all the various biota. {yields} Concentrations of Cs were greater in periphyton than in plankton

Dam Design can Impede Adaptive Management of Environmental Flows: A Case Study from the Opuha Dam, New Zealand

Science.gov (United States)

Lessard, JoAnna; Murray Hicks, D.; Snelder, Ton H.; Arscott, David B.; Larned, Scott T.; Booker, Doug; Suren, Alastair M.

2013-02-01

The Opuha Dam was designed for water storage, hydropower, and to augment summer low flows. Following its commissioning in 1999, algal blooms (dominated first by Phormidium and later Didymosphenia geminata) downstream of the dam were attributed to the reduced frequency and magnitude of high-flow events. In this study, we used a 20-year monitoring dataset to quantify changes associated with the dam. We also studied the effectiveness of flushing flows to remove periphyton from the river bed. Following the completion of the dam, daily maximum flows downstream have exceeded 100 m3 s-1 only three times; two of these floods exceeded the pre-dam mean annual flood of 203 m3 s-1 (compared to 19 times >100 m3 s-1 and 6 times >203 m3 s-1 in the 8 years of record before the dam). Other changes downstream included increases in water temperature, bed armoring, frequency of algal blooms, and changes to the aquatic invertebrate community. Seven experimental flushing flows resulted in limited periphyton reductions. Flood wave attenuation, bed armoring, and a shortage of surface sand and gravel, likely limited the effectiveness of these moderate floods. Floods similar to pre-dam levels may be effective for control of periphyton downstream; however, flushing flows of that magnitude are not possible with the existing dam infrastructure. These results highlight the need for dams to be planned and built with the capacity to provide the natural range of flows for adaptive management, particularly high flows.

Biological and associated water-quality data for lower Olmos Creek and upper San Antonio River, San Antonio, Texas, April - September 1989

Science.gov (United States)

Taylor, R. Lynn; Ferreira, Rodger F.

1995-01-01

Biological and associated water-quality data were collected from lower Olmos Creek and upper San Antonio River in San Antonio, Texas, during April-September 1989. Benthic macroinvertebrate, periphyton, and phytoplankton communities were sampled at three sites along the Olmos Creek/San Antonio River system. Total mean densities of benthic macroinvertebrates for the three sites ranged from 670 to 10,000 organisms per square meter. The most abundant macroinvertebrates were the class Insecta (insects). Total densities of periphyton ranged from 2,900 to 110,000 cells per square millimeter. Cyanophyta (blue-green algae) and Bacillariophyta (diatoms) were the predominant periphyton organisms. Total densities of phyto- plankton ranged from 5,000 to 47,000 cells per square milliliter. Blue-green algae accounted for more than one- half of the phytoplankton in each sample. Hardness ranged from 160 to 250 milligrams per liter as calcium carbonate, and alkalinity ranged from 130 to 220 milligrams per liter as calcium carbonate. The largest dissolved nitrite concentration was 0.038 milligram per liter. The largest total phosphorus concentration was 0.150 milligram per liter, over one-half of which was dissolved orthophosphate. Total aluminum and total iron were the only trace elements in water to exceed the reporting threshold by large concen- trations. Total aluminum concentrations ranged from 70 to 280 micrograms per liter, and total iron concentrations ranged from 70 to 340 micrograms per liter. Lead was the most prominent trace element in bottom-material samples, with concentrations ranging from 30 to 230 micrograms per gram.

Microbial diversity in different compartments of an aquaponics system.

Science.gov (United States)

Schmautz, Zala; Graber, Andreas; Jaenicke, Sebastian; Goesmann, Alexander; Junge, Ranka; Smits, Theo H M

2017-05-01

Aquaponics is a solution for sustainable production of fish and plants in a single semi-closed system, where nutrient-rich water from the aquaculture provides nutrients for plant growth. We examined the microbial communities within an experimental aquaponics system. Whereas the fish feces contained a separate community dominated by bacteria of the genus Cetobacterium, the samples from plant roots, biofilter, and periphyton were more similar to each other, while the communities were more diverse. Detailed examination of the data gave the first indications to functional groups of organisms in the different compartments of the aquaponic system. As other nitrifiers other than members of the genus Nitrospira were only present at low numbers, it was anticipated that Nitrospirae may perform the nitrification process in the biofilm.

Protocols for collection of streamflow, water-quality, streambed-sediment, periphyton, macroinvertebrate, fish, and habitat data to describe stream quality for the Hydrobiological Monitoring Program, Equus Beds Aquifer Storage and Recovery Program, city of Wichita, Kansas

Science.gov (United States)

Stone, Mandy L.; Rasmussen, Teresa J.; Bennett, Trudy J.; Poulton, Barry C.; Ziegler, Andrew C.

2012-01-01

The city of Wichita, Kansas uses the Equus Beds aquifer, one of two sources, for municipal water supply. To meet future water needs, plans for artificial recharge of the aquifer have been implemented in several phases. Phase I of the Equus Beds Aquifer Storage and Recovery (ASR) Program began with injection of water from the Little Arkansas River into the aquifer for storage and subsequent recovery in 2006. Construction of a river intake structure and surface-water treatment plant began as implementation of Phase II of the Equus Beds ASR Program in 2010. An important aspect of the ASR Program is the monitoring of water quality and the effects of recharge activities on stream conditions. Physical, chemical, and biological data provide the basis for an integrated assessment of stream quality. This report describes protocols for collecting streamflow, water-quality, streambed-sediment, periphyton, macroinvertebrate, fish, and habitat data as part of the city of Wichita's hydrobiological monitoring program (HBMP). Following consistent and reliable methods for data collection and processing is imperative for the long-term success of the monitoring program.

Nutrient and chlorophyll relations in selected streams of the New England Coastal Basins in Massachusetts and New Hampshire, June-September 2001

Science.gov (United States)

Riskin, Melissa L.; Deacon, J.R.; Liebman, M.L.; Robinson, K.W.

2003-01-01

The U.S. Environmental Protection Agency is developing guidance to assist states with defining nutrient criteria for rivers and streams and to better describe nutrient-algal relations. As part of this effort, 13 wadeable stream sites were selected, primarily in eastern Massachusetts, for a nutrient-assessment study during the summer of 2001. The sites represent a range of water-quality impairment conditions (reference, moderately impaired, impaired) based on state regulatory agency assessments and previously assessed nitrogen, phosphorus, and dissolved-oxygen data. In addition, a combination of open- and closed-canopy locations were sampled at six of the sites to investigate the effect of sunlight on algal growth. Samples for nutrients and for chlorophyll I from phytoplankton and periphyton were collected at all stream sites. Total nitrogen (dissolved nitrite + nitrate + total ammonia + organic nitrogen) and total phosphorus (phosphorus in an unfiltered water sample) concentrations were lowest at reference sites and highest at impaired sites. There were statistically significant differences (p phytoplankton were not significantly different among site impairment designations. Concentrations of chlorophyll a from periphyton were highest at nutrient-impaired open-canopy sites. Chlorophyll a concentrations from periphyton samples were positively correlated with total nitrogen and total phosphorus at the open- and closed-canopy sites. Correlations were higher at open-canopy sites (p periphyton samples were observed between the open- and closed-canopy sites (p relations between total nitrogen and total phosphorus to periphyton chlorophyll a in wadeable streams from this study were quantified to present potential techniques for determining nutrient concentrations. Linear regression was used to estimate the total nitrogen and total phosphorus concentrations that corresponded to various chlorophyll a concentrations. On the basis of this relation, a median concentration for

Southern marl prairies conceptual ecological model

Science.gov (United States)

Davis, S.M.; Loftus, W.F.; Gaiser, E.E.; Huffman, A.E.

2005-01-01

About 190,000 ha of higher-elevation marl prairies flank either side of Shark River Slough in the southern Everglades. Water levels typically drop below the ground surface each year in this landscape. Consequently, peat soil accretion is inhibited, and substrates consist either of calcitic marl produced by algal periphyton mats or exposed limestone bedrock. The southern marl prairies support complex mosaics of wet prairie, sawgrass sawgrass (Cladium jamaicense), tree islands, and tropical hammock communities and a high diversity of plant species. However, relatively short hydroperiods and annual dry downs provide stressful conditions for aquatic fauna, affecting survival in the dry season when surface water is absent. Here, we present a conceptual ecological model developed for this landscape through scientific concensus, use of empirical data, and modeling. The two major societal drivers affecting the southern marl prairies are water management practices and agricultural and urban development. These drivers lead to five groups of ecosystem stressors: loss of spatial extent and connectivity, shortened hydroperiod and increased drought severity, extended hydroperiod and drying pattern reversals, introduction and spread of non-native trees, and introduction and spread of non-native fishes. Major ecological attributes include periphyton mats, plant species diversity and community mosaic, Cape Sable seaside sparrow (Ammodramus maritimus mirabilis), marsh fishes and associated aquatic fauna prey base, American alligator (Alligator mississippiensis), and wading bird early dry season foraging. Water management and development are hypothesized to have a negative effect on the ecological attributes of the southern marl prairies in the following ways. Periphyton mats have decreased in cover in areas where hydroperiod has been significantly reduced and changed in community composition due to inverse responses to increased nutrient availability. Plant species diversity and

Benthic algal production across lake size gradients: interactions among morphometry, nutrients, and light.

Science.gov (United States)

Vadeboncoeur, Yvonne; Peterson, Garry; Vander Zanden, M Jake; Kalff, Jacob

2008-09-01

Attached algae play a minor role in conceptual and empirical models of lake ecosystem function but paradoxically form the energetic base of food webs that support a wide variety of fishes. To explore the apparent mismatch between perceived limits on contributions of periphyton to whole-lake primary production and its importance to consumers, we modeled the contribution of periphyton to whole-ecosystem primary production across lake size, shape, and nutrient gradients. The distribution of available benthic habitat for periphyton is influenced by the ratio of mean depth to maximum depth (DR = z/ z(max)). We modeled total phytoplankton production from water-column nutrient availability, z, and light. Periphyton production was a function of light-saturated photosynthesis (BPmax) and light availability at depth. The model demonstrated that depth ratio (DR) and light attenuation strongly determined the maximum possible contribution of benthic algae to lake production, and the benthic proportion of whole-lake primary production (BPf) declined with increasing nutrients. Shallow lakes (z benthic or pelagic primary productivity depending on trophic status. Moderately deep oligotrophic lakes had substantial contributions by benthic primary productivity at low depth ratios and when maximum benthic photosynthesis was moderate or high. Extremely large, deep lakes always had low fractional contributions of benthic primary production. An analysis of the world's largest lakes showed that the shapes of natural lakes shift increasingly toward lower depth ratios with increasing depth, maximizing the potential importance of littoral primary production in large-lake food webs. The repeatedly demonstrated importance of periphyton to lake food webs may reflect the combination of low depth ratios and high light penetration characteristic of large, oligotrophic lakes that in turn lead to substantial contributions of periphyton to autochthonous production.

Aquatic Resources of Rocky Mountain Arsenal Adams County, Colorado

Science.gov (United States)

1989-09-01

Consequently, temperatures rise and oxygen levels fall. Primary producers in these stretches shift from periphyton to phytoplankton (suspended algae ...trees and have rocky substrates. Primary production in these cold- water and coolwater reaches is generally limited to periphyton (attached algae ...Adams County. Biotic components investigated included phytoplankton , zooplankton, aquatic macrophytes, benthic macroinvertebrates, fish eggs and

Transformation of chiral polychlorinated biphenyls (PCBs) in a stream food web

Science.gov (United States)

Dang, V.D.; Walters, D.M.; Lee, C.M.

2010-01-01

The enantiomeric composition of chiral PCB congeners was determined in Twelvemile Creek (Clemson, SC) to examine potential mechanisms of biotransformation in a stream food web. We measured enantiomeric fractions (EFs) of six PCB atropisomers (PCBs 84, 91, 95, 136, 149, and 174) in surface sediment, fine benthic organic matter (FBOM), coarse particulate organic matter (CPOM), periphyton, Asian clam, mayflies, yellowfin shiner, and semipermeable membrane devices (SPMDs) using gas chromatography (GC-ECD). Nonracemic EFs of PCBs 91, 95, 136, and 149 were measured in almost all samples. Enantiomeric compositions of PCBs 84 and 174 were infrequently detected with racemic EFs measured in samples except for a nonracemic EF of PCB 84 in clams. Nonracemic EFs of PCBs 91, 136, and 149 in SPMDs may be due to desorption of nonracemic residues from FBOM. EFs for some atropisomers were significantly different among FBOM, CPOM, and periphyton, suggesting that their microbial communities have different biotransformation processes. Nonracemic EFs in clams and fish suggest both in vivo biotransformation and uptake of nonracemic residues from their food sources. Longitudinal variability in EFs was generally low among congeners observed in matrices. ?? 2010 American Chemical Society.

Mechanisms regulating amphipod population density within macroalgal communities with low predator impact

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Hartvig Christie

2004-04-01

Full Text Available In eight mesocosms (land based basins macroalgae communities with associated fauna were transplanted from the sea and established during two years. Then, different doses of nutrients (N and P were added to the basins throughout the following three years. During the period of nutrient addition, macroinvertebrate grazers showed seasonal fluctuations with densities usually between 500,000 and 1 million individuals per mesocosm during summer and to a level of about 100,000 during winter. The macroinvertebrate grazers mainly consisted of about 10 species of amphipods and isopods, among which the amphipod Gammarus locusta dominated strongly by biomass. Although the number of predators was very low, the grazer populations never reached a density where considerable grazing impact could be found on the macroalgae. No increase in grazer density was found in the basins with improved nutrient conditions. Thus food quality may be insufficient for further population growth, or density dependant regulation mechanisms may have prevented the grazers from flourishing and overgrazing the system. In aquarium experiments we showed that G. locusta could grow and reproduce on Fucus serratus, Ulva lactuca, periphyton and detritus, and that cannibalism by adult G. locusta on juveniles may have great impact on the population growth. The basins were run with a water flow through system. Nets were placed in front of the inflow and outflow tubes to measure immigration and emigration. Only few individuals (and no Gammarus sp. were recorded in the inflowing water, while high numbers of both amphipods and isopods were found in the outflowing water. Emigration reached peak values during night-time, and it was then two to three times as high as during day-time. Emigration of mobile grazers from the basins amounted to 1-2% of the standing stock daily. These mechanisms that regulate grazers do contribute to maintenance of the seaweed dominance and thus the stability of the seaweed

Downstream changes in spring-fed stream invertebrate communities: the effect of increased temperature range?

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Russell G. DEATH

2011-09-01

Full Text Available Reduced thermal amplitude has been highlighted as a limiting factor for aquatic invertebrate diversity in springs. Moving downstream water temperature range increases and invertebrate richness is expected to change accordingly. In the present study temperature patterns were investigated in seven spring-fed streams, between April 2001 and November 2002, and compared to five run-off-fed streams to assess the degree of crenic temperature constancy. Temperature and physico-chemical characteristics of the water, and food resource levels were measured, and the invertebrate fauna collected at 4 distances (0, 100, 500 m and 1 km from seven springs in the North and South Islands of New Zealand. Temperature variability was greater for run-off-fed streams than for springs, and increased in the spring-fed streams with distance from the source. Periphyton and physico-chemical characteristics of the water did not change markedly over the 1 km studied, with the exception of water velocity and organic matter biomass, which increased and decreased, respectively. The rate of increase in temperature amplitude differed greatly for the studied springs, probably being affected by flow, altitude, and the number and type of tributaries (i.e., spring- or run-off-fed joining the spring-fed stream channel. Longitudinal changes in the number and evenness of invertebrate taxa were positively correlated to thermal amplitude (rs = 0.8. Moving downstream, invertebrate communities progressively incorporated taxa with higher mobility and taxa more common in nearby run-off-fed streams. Chironomids and non-insect taxa were denser at the sources. Chironomid larvae also numerically dominated communities 100 and 500 m downstream from the sources, together with Pycnocentria spp. and Zelolessica spp., while taxa such as Hydora sp. and Hydraenidae beetles, the mayflies Deleatidium spp. and Coloburiscus humeralis, and the Trichoptera Pycnocentrodes spp., all had greater abundances 1 km

Changes in algal stable isotopes following nutrient and peat amendments in oil sands aquatic reclamation

International Nuclear Information System (INIS)

Farwell, A.; Chen, H.; Boutsivongskad, M.; Dixon, D.

2010-01-01

The processing of oil sands in Alberta generates large volumes of processed material that must be reclaimed. Processed water and solids (PW/S) contain higher levels of naturally occurring compounds such as naphthenic acids (NAs) and polycyclic aromatic compounds (PACs). Organic carbon and nitrogen are some of the constituents in PW/S that may provide nutrient sources for aquatic reclamation sites as they develop into viable ecosystems. This study was conducted to assess the modifying factors that may affect the stable carbon and nitrogen isotope values of primary production in oil sands aquatic reclamation. Both field-based microcosm studies and laboratory studies were used to evaluate the changes in the growth and stable isotope values of phytoplankton, periphyton and/or filamentous algae along gradients of dissolved organic carbon (DOC), dissolved inorganic carbon (DIC), nitrogen and phosphorus. Various types of reclamation substrates were used in the study, including various combinations of sand, mature fine tailings, peat and process water. Results showed different levels of growth depending on both the water and substrate type. Typically, periphyton from oil sands reclamation sites were more enriched in 15N than the reference site. Periphyton from one site known as the MP site was more enriched in 13C than periphyton from another site know as the Shallow Wetland South Ditch (SWSD). However, periphyton in the demonstration pond (DP) was more 13C depleted than the reference site. Findings from this study indicate that carbon isotopes are influenced by other factors, such as nutrients.

Environmental and Cultural Impact. Proposed Tennessee Colony Reservoir, Trinity River, Texas. Volume I. Summary Report.

Science.gov (United States)

1972-01-01

high populations of phytoplankton and periphyton , indi- cate excessive eutrophic conditions. Rates of primary production are comparatively high. The...species of algae in the phytoplankton and periphyton are those .commonly associated with organic pollution, and the high numbers for total coliform...uni- quely important geological areas within or adjacent to the proposed project area. Other geologically related pheno- 4 I mena and of potential

RESPONSE OF NUTRIENTS, BIOFILM, AND BENTHIC INSECTS TO SALMON CARCASS ADDITION

Science.gov (United States)

Salmon carcass addition to streams is expected to increase stream productivity at multiple trophic levels. This study examined stream nutrient (nitrogen, phosphorus, and carbon), epilithic biofilm (ash-free dry mass and chlorophyll a), leaf-litter decomposition, and macroinverte...

A transition to white LED increases ecological impacts of nocturnal illumination on aquatic primary producers in a lowland agricultural drainage ditch.

Science.gov (United States)

Grubisic, Maja; van Grunsven, Roy H A; Manfrin, Alessandro; Monaghan, Michael T; Hölker, Franz

2018-05-14

The increasing use of artificial light at night (ALAN) has led to exposure of freshwater ecosystems to light pollution worldwide. Simultaneously, the spectral composition of nocturnal illumination is changing, following the current shift in outdoor lighting technologies from traditional light sources to light emitting diodes (LED). LEDs emit broad-spectrum white light, with a significant amount of photosynthetically active radiation, and typically a high content of blue light that regulates circadian rhythms in many organisms. While effects of the shift to LED have been investigated in nocturnal animals, its impact on primary producers is unknown. We performed three field experiments in a lowland agricultural drainage ditch to assess the impacts of a transition from high-pressure sodium (HPS) to white LED illumination (color temperature 4000 K) on primary producers in periphyton. In all experiments, we compared biomass and pigment composition of periphyton grown under a natural light regime to that of periphyton exposed to nocturnal HPS or, consecutively, LED light of intensities commonly found in urban waters (approximately 20 lux). Periphyton was collected in time series (1-13 weeks). We found no effect of HPS light on periphyton biomass; however, following a shift to LED the biomass decreased up to 62%. Neither light source had a substantial effect on pigment composition. The contrasting effects of the two light sources on biomass may be explained by differences in their spectral composition, and in particular the blue content. Our results suggest that spectral composition of the light source plays a role in determining the impacts of ALAN on periphyton and that the ongoing transition to LED may increase the ecological impacts of artificial lighting on aquatic primary producers. Reduced biomass in the base of the food web can impact ecosystem functions such as productivity and food supply for higher trophic levels in nocturnally-lit ecosystems. Copyright �

Stable carbon and nitrogen isotopes as indicators of habitat selection by cultured and natural fish preferences. A case study of ayu

International Nuclear Information System (INIS)

Wei Huang; Kyushu University, Fukuoka; Xixi Chen; Xiaobo Liu; Shinichiro Yano

2017-01-01

Reliable indicators on whether natural and cultured fish exhibit differences in habitat preferences are lacking. In this study, δ 13 C and δ 15 N were used to distinguish the habitat preferences of cultured versus natural ayu and their prey (periphyton) in a typical riffle-pool river reach. It found that the δ 13 C of natural ayu (-13.747‰) was consistent with that of periphyton in riffles (-14.611‰), while the δ 13 C of cultured ayu (-19.088‰) was consistent with that of periphyton (-19.711‰) in pools. The results indicated that cultured ayu appear to favor pools whereas natural ayu favor riffles, and δ 13 C and δ 15 N represent potential reliable indicators of habitat preferences of cultured ayu. (author)

Didymosphenia geminata in the Upper Esopus Creek: Current Status, Variability, and Controlling Factors.

Science.gov (United States)

George, Scott Daniel; Baldigo, Barry Paul

2015-01-01

In May of 2009, the bloom-forming diatom Didymosphenia geminata was first identified in the Upper Esopus Creek, a key tributary to the New York City water-supply and a popular recreational stream. The Upper Esopus receives supplemental flows from the Shandaken Portal, an underground aqueduct delivering waters from a nearby basin. The presence of D. geminata is a concern for the local economy, water supply, and aquatic ecosystem because nuisance blooms have been linked to degraded stream condition in other regions. Here we ascertain the extent and severity of the D. geminata invasion, determine the impact of supplemental flows from the Portal on D. geminata, and identify potential factors that may limit D. geminata in the watershed. Stream temperature, discharge, and water quality were characterized at select sites and periphyton samples were collected five times at 6 to 20 study sites between 2009 and 2010 to assess standing crop, diatom community structure, and density of D. geminata and all diatoms. Density of D. geminata ranged from 0-12 cells cm(-2) at tributary sites, 0-781 cells cm(-2) at sites upstream of the Portal, and 0-2,574 cells cm(-2) at sites downstream of the Portal. Survey period and Portal (upstream or downstream) each significantly affected D. geminata cell density. In general, D. geminata was most abundant during the November 2009 and June 2010 surveys and at sites immediately downstream of the Portal. We found that D. geminata did not reach nuisance levels or strongly affect the periphyton community. Similarly, companion studies showed that local macroinvertebrate and fish communities were generally unaffected. A number of abiotic factors including variable flows and moderate levels of phosphorous and suspended sediment may limit blooms of D. geminata in this watershed.

Didymosphenia geminata in the Upper Esopus Creek: Current Status, Variability, and Controlling Factors.

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Scott Daniel George

Full Text Available In May of 2009, the bloom-forming diatom Didymosphenia geminata was first identified in the Upper Esopus Creek, a key tributary to the New York City water-supply and a popular recreational stream. The Upper Esopus receives supplemental flows from the Shandaken Portal, an underground aqueduct delivering waters from a nearby basin. The presence of D. geminata is a concern for the local economy, water supply, and aquatic ecosystem because nuisance blooms have been linked to degraded stream condition in other regions. Here we ascertain the extent and severity of the D. geminata invasion, determine the impact of supplemental flows from the Portal on D. geminata, and identify potential factors that may limit D. geminata in the watershed. Stream temperature, discharge, and water quality were characterized at select sites and periphyton samples were collected five times at 6 to 20 study sites between 2009 and 2010 to assess standing crop, diatom community structure, and density of D. geminata and all diatoms. Density of D. geminata ranged from 0-12 cells cm(-2 at tributary sites, 0-781 cells cm(-2 at sites upstream of the Portal, and 0-2,574 cells cm(-2 at sites downstream of the Portal. Survey period and Portal (upstream or downstream each significantly affected D. geminata cell density. In general, D. geminata was most abundant during the November 2009 and June 2010 surveys and at sites immediately downstream of the Portal. We found that D. geminata did not reach nuisance levels or strongly affect the periphyton community. Similarly, companion studies showed that local macroinvertebrate and fish communities were generally unaffected. A number of abiotic factors including variable flows and moderate levels of phosphorous and suspended sediment may limit blooms of D. geminata in this watershed.

Use of cyanobacteria to assess water quality in running waters

International Nuclear Information System (INIS)

Douterelo, I.; Perona, E.; Mateo, P.

2004-01-01

Epilithic cyanobacterial communities in rivers in the province of Madrid (Spain) and their relationship with water quality were studied. Sampling locations above and below outlets for sewage effluent and other wastes from human settlements were selected. We aimed to evaluate the use of cyanobacteria as potential indicators of pollution in running waters. Large increases in nutrient concentrations were always observed at downstream sampling sites. A decrease in species richness and the Margalef diversity index were associated with these increases in nutrient load. Differences in cyanobacterial community structure were also observed. A higher proportion of cyanobacteria belonging to the Oscillatoriales order predominated at sampling sites with higher nutrient content. However, Nostocales species were more abundant at upstream sites characterized by lower nutrient load than at downstream locations. The soluble reactive phosphate (SRP) had a threshold effect on cyanobacterial biomass: a decrease in phycobiliprotein content as SRP increased, reaching a minimum, followed by an increase in abundance. This increase may be attributed to hypertrophic conditions in those locations. Our results and literature data confirm the suitability of this phototroph community for monitoring eutrophication in rivers - Taxonomic composition of cyanobacteria is a sensitive indicator of river water quality

Use of cyanobacteria to assess water quality in running waters

Energy Technology Data Exchange (ETDEWEB)

Douterelo, I.; Perona, E.; Mateo, P

2004-02-01

Epilithic cyanobacterial communities in rivers in the province of Madrid (Spain) and their relationship with water quality were studied. Sampling locations above and below outlets for sewage effluent and other wastes from human settlements were selected. We aimed to evaluate the use of cyanobacteria as potential indicators of pollution in running waters. Large increases in nutrient concentrations were always observed at downstream sampling sites. A decrease in species richness and the Margalef diversity index were associated with these increases in nutrient load. Differences in cyanobacterial community structure were also observed. A higher proportion of cyanobacteria belonging to the Oscillatoriales order predominated at sampling sites with higher nutrient content. However, Nostocales species were more abundant at upstream sites characterized by lower nutrient load than at downstream locations. The soluble reactive phosphate (SRP) had a threshold effect on cyanobacterial biomass: a decrease in phycobiliprotein content as SRP increased, reaching a minimum, followed by an increase in abundance. This increase may be attributed to hypertrophic conditions in those locations. Our results and literature data confirm the suitability of this phototroph community for monitoring eutrophication in rivers - Taxonomic composition of cyanobacteria is a sensitive indicator of river water quality.

Fish but Not Macroinvertebrates Promote Trophic Cascading Effects in High Density Submersed Plant Experimental Lake Food Webs in Two Contrasting Climate Regions

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Carlos Iglesias

2017-07-01

Full Text Available Predators play a key role in the functioning of shallow lakes. Differences between the response of temperate and subtropical systems to fish predation have been proposed, but experimental evidence is scarce. To elucidate cascading effects produced by predators in contrasting climatic zones, we conducted a mesocosm experiment in three pairs of lakes in Uruguay and Denmark. We used two typical planktivorous-omnivorous fish species (Jenynsia multidentata + Cnesterodon decemmaculatus and Gasterosteus aculeatus + Perca fluviatilis and one littoral omnivorous-predatory macroinvertebrate (Palaemonetes argentinus and Gammarus lacustris, alone and combined, in numbers resembling natural densities. Fish predation on zooplankton increased phytoplankton biomass in both climate zones, whereas the effects of predatory macroinvertebrates on zooplankton and phytoplankton were not significant in either climate zone. Macroinvertebrates (that freely colonized the sampling devices were diminished by fish in both climate areas; however, periphyton biomass did not vary among treatments. Our experiments demonstrated that fish affected the structure of both planktonic and littoral herbivorous communities in both climate regions, with a visible positive cascading effect on phytoplankton biomass, but no effects on periphyton. Altogether, fish impacts appeared to be a strong driver of turbid water conditions in shallow lakes regardless of climatic zone by indirectly contributing to increasing phytoplankton biomass.

Evaluation of a Florida coastal golf complex as a local and watershed source of bioavailable contaminants

International Nuclear Information System (INIS)

Lewis, Michael A.; Quarles, Robert L.; Dantin, Darrin D.; Moore, James C.

2004-01-01

Contaminant fate in coastal areas impacted by golf course runoff is not well understood. This report summarizes trace metal, pesticide and PCB residues for colonized periphyton, Ruppia maritima (widgeon grass), Callinectes sapidus Rathbun (blue crabs) and Crassostrea virginica Gemlin (Eastern oyster) collected from areas adjacent to a Florida golf course complex which receive runoff containing reclaimed municipal wastewater. Concentrations of 19 chlorinated pesticides and 18 PCB congeners were usually below detection in the biota. In contrast, 8 trace metals were commonly detected although concentrations were not usually significantly different for biota collected from reference and non-reference coastal areas. Residue concentrations in decreasing order were typically: zinc, arsenic, copper, chromium, lead, nickel, cadmium and mercury. Mean BCF values for the eight trace metals ranged between 160-57 000 (periphyton), 79-11 033 (R. maritima), 87-162 625 (C. virginica) and 12-9800 (C. sapidus). Most trace metal residues in periphyton colonized adjacent to the golf complex, were either similar to or significantly less than those reported for periphyton colonized in nearby coastal areas impacted by urban stormwater runoff and treated municipal and industrial wastewater discharges. Consequently, the recreational complex does not appear to be a major source of bioavailable contaminants locally nor in the immediate watershed based on results for the selected biota

Ecological Study of Periphytic Algal Community of Doodh Ganga and Khansha-Mansha Streams of Yusmarg Forests: A Health Resort of Kashmir Valley, India

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Rafia Rashid

2013-06-01

Full Text Available The present study on Doodh Ganga and Khansha-Mansha streams of Yusmarg forests deals with the general ecological studies on periphytic algal community in terms of species composition and density. During the present investigation the periphytic algal community of Doodh Ganga and Khansha-Mansha streams were represented by 30 taxa which belonged to 4 major classes namely Bacillariophyceae (14, Chlorophyceae (11, Cyanophyceae (4 and Euglenophyceae (1. The most common periphytic species encountered across all the sites included Closterium sp., Zygnema sp., Amphora sp., Cymbella sp., Epithemia sp., Fragilaria sp., Navicula sp., Synedra sp., Tabellaria sp., Lyngbya sp. and Phormidium sp. Among the two streams, Doodh Ganga showed large number of taxa (45 and Khansha-Mansha was having 37 taxa of periphyton. Bacillariophyceae was the dominant group both in diversity and density and included 14 taxa contributing 57% of total periphytic algal population. Cyanophyceae forming the second dominant class was represented by 4 genera comprising 22% of the total periphytic algae .Chlorophyceae ranked third in its dominance pattern with 11 genera forming 20% of all the periphytic algae. Euglenophyceae was represented by only one species of Euglena sp. forming 1% of all the periphytic algae and found only at site 2 (Doodh Ganga downstream.Amongst the study sites the highest (5.69 value of Shannon Weiner Index was found at Doodh Ganga upstream while as lowest (4.38 at Khansha-Mansha downstream. The primary conclusion is that the streams, having crystal clear water, and are free from pollution as Chlorophyceae are better represented in both the streams. Further, as a result of less anthropogenic pressures the quality of water is fairly good.

Effects of fish density and river fertilization on algal standing stocks, invertebrates communities, and fish production in an Arctic River

Science.gov (United States)

Deegan, Linda A.; Peterson, B.J.; Golden, H.; McIvor, C.C.; Miller, M.C.

1997-01-01

This study examined the relative importance of bottom-up and top-down controls of an arctic stream food web by simultaneous manipulation of the top predator and nutrient availability. We created a two-step trophic system (algae to insects) by removal of the top predator (Arctic grayling, Thymallus arcticus) in fertilized and control stream reaches. Fish abundance was also increased 10 times to examine the effect of high fish density on stream ecosystem dynamics and fish. We measured the response of epilithic algae, benthic and drifting insects, and fish to nutrient enrichment and to changes in fish density. Insect grazers had little effect on algae and fish had little effect on insects. In both the control and fertilized reaches, fish growth, energy storage, and reproductive response of females declined with increased fish density. Fish growth and energy storage were more closely correlated with per capita insect availability than with per capita algal standing stock

Cu removal and response mechanisms of periphytic biofilms in a tubular bioreactor.

Science.gov (United States)

Ma, Lan; Wang, Fengwu; Yu, Yuanchun; Liu, Junzhuo; Wu, Yonghong

2018-01-01

This work studied Cu removal and response mechanisms of periphytic biofilms in a tubular bioreactor. Periphytic biofilms immobilized in a tubular bioreactor were used to remove Cu from wastewater with different Cu concentrations. Results showed that periphytic biofilms had a high removal efficiency (max. 99%) at a hydraulic retention time (HRT) of 12h under initial Cu concentrations of 2.0 and 10.0mgL -1 . Periphyton quickly adapted to Cu stress by regulating the community composition. Species richness, evenness and carbon metabolic diversity of the periphytic community increased when exposed to Cu. Diatoms, green algae, and bacteria (Gammaproteobacteria and Bacteroidia) were the dominant microorganisms and responsible for Cu removal. This study indicates that periphytic biofilms are promising in Cu removal from wastewater due to their strong adaptation capacity to Cu toxicity and also provides valuable information for understanding the relationships between microbial communities and heavy metal stress. Copyright © 2017 Elsevier Ltd. All rights reserved.

The health of benthic diatom assemblages in lower stretch

Indian Academy of Sciences (India)

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.

Cyanobacteria in Coral Reef Ecosystems: A Review

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L. Charpy

2012-01-01

Full Text Available Cyanobacteria have dominated marine environments and have been reef builders on Earth for more than three million years (myr. Cyanobacteria still play an essential role in modern coral reef ecosystems by forming a major component of epiphytic, epilithic, and endolithic communities as well as of microbial mats. Cyanobacteria are grazed by reef organisms and also provide nitrogen to the coral reef ecosystems through nitrogen fixation. Recently, new unicellular cyanobacteria that express nitrogenase were found in the open ocean and in coral reef lagoons. Furthermore, cyanobacteria are important in calcification and decalcification. All limestone surfaces have a layer of boring algae in which cyanobacteria often play a dominant role. Cyanobacterial symbioses are abundant in coral reefs; the most common hosts are sponges and ascidians. Cyanobacteria use tactics beyond space occupation to inhibit coral recruitment. Cyanobacteria can also form pathogenic microbial consortia in association with other microbes on living coral tissues, causing coral tissue lysis and death, and considerable declines in coral reefs. In deep lagoons, coccoid cyanobacteria are abundant and are grazed by ciliates, heteroflagellates, and the benthic coral reef community. Cyanobacteria produce metabolites that act as attractants for some species and deterrents for some grazers of the reef communities.

Impacts of drought and crayfish invasion on stream ecosystem structure and function

Science.gov (United States)

Magoulick, Daniel D.

2014-01-01

Drought and seasonal drying can be important disturbance events in many small streams, leading to intermittent or isolated habitats. Many small streams contain crayfish populations that are often keystone or dominant species in these systems. I conducted an experiment in stream mesocosms to examine the effects of drought and potential ecological redundancy of a native and invasive crayfish species. I examined the effects of drought (drought or control) and crayfish presence (none, native crayfish Orconectes eupunctus or invasive crayfish Orconectes neglectus) on stream mesocosm structure and function (leaf breakdown, community metabolism, periphyton, sediment and chironomid densities) in a fully factorial design. Each mesocosm contained a deep and shallow section, and drought treatments had surface water present (5-cm depth) in deep sections where tiles and leaf packs were placed. Drought and crayfish presence did not interact for any response variable. Drought significantly reduced leaf breakdown, and crayfish presence significantly increased leaf breakdown. However, the native and invasive crayfish species did not differ significantly in their effects on leaf breakdown. Drought significantly reduced primary production and community respiration overall, whereas crayfish presence did not significantly affect primary production and community respiration. Neither drought nor crayfish presence significantly affected periphyton overall. However, drought significantly reduced autotrophic index (AI), and crayfish presence increased AI. Inorganic sediment and chironomid density were not affected by drought, but both were significantly reduced by crayfish presence. O. eupunctus reduced AI and sediment more than O. neglectus did. Neither drought nor crayfish species significantly affected crayfish growth or survival. Drought can have strong effects on ecosystem function, but weaker effects on benthic structure. Crayfish can have strong effects on ecosystem

Recovery of Three Arctic Stream Reaches From Experimental Nutrient Enrichment.

Science.gov (United States)

Green, A. C.; Benstead, J. P.; Deegan, L. A.; Peterson, B. J.; Bowden, W. B.; Huryn, A. D.; Slavik, K.; Hershey, A. E.

2005-05-01

We examined multi-year patterns in community recovery from experimental low-concentration nutrient (N+P and P only) enrichment in three reaches of two Arctic tundra streams (Kuparuk River and Oksrukuyik Creek) on the North Slope of Alaska (USA). Rates of recovery varied among community components and depended on duration of enrichment (2 to 13 consecutive growing seasons). Biomass and C:P ratio of epilithic algae returned to reference levels rapidly (within 2 years), regardless of enrichment duration. Bryophyte cover, which increased greatly after long-term enrichment (>8 years), recovered to reference levels only after 7 years, when a storm scoured most remnant moss in the recovering reach. Persistence of bryophytes slowed recovery rates of insect taxa that had either been positively (e.g., Ephemerella, most chironomid taxa) or negatively (e.g., Orthocladius rivulorum) affected by this shift in dominant primary producer and its consequence for benthic habitat. Growth of Arctic grayling (adults and young-of-year), the top predator, returned to reference rates within two years. Recovery of these Arctic stream ecosystems from nutrient enrichment was consequently controlled largely by interactions between duration of enrichment and physical disturbance, mediated through physical habitat shifts caused by bryophytes.

Multifractal characteristics of NDVI maps in space and time in the Community of Madrid (Spain)

Science.gov (United States)

Sotoca, Juan J. Martin; Saa-Requejo, Antonio; Grau, Juan B.; Tarquis, Ana M.

2015-04-01

Satellite information has contributed to improve our understanding of the spatial variability of hydro-climatic and ecological processes. Vegetation activity is tightly coupled with climate, hydro-ecological fluxes, and terrain dynamics in river basins at a wide range of space-time scales (Scheuring and Riedi, 1994). Indices of vegetation activity are constructed using satellite information of reflectance of the relevant spectral bands which enhance the contribution of vegetation being Normalized Difference Vegetation Index (NDVI) widely used. How can we study such a complex system? Multifractals and fractals are related techniques mainly used in physics to characterize the scaling behaviour of a system; they differ in that fractals look at the geometry of presence/absence patterns, while multifractals look at the arrangement of quantities such as population or biomass densities (Saravia et al., 2012). Scaling laws are an emergent general feature of ecological systems; they reflect constraints in their organization that can provide tracks about the underlying mechanisms (Solé and Bascompte, 2006). In this work, we have applied these techniques to study the spatial pattern through one year of NDVI maps. A rectangular area that includes the Community of Madrid and part of the surroundings, consisting of 300 x 280 pixels with a resolution of 500 x 500 m2 has been selected and monthly NDVI maps analyzed using the multifractal spectrum and the map of singularities (Cheng and Agterberg, 1996). The results show a cyclical pattern in the multifractal behaviour and singularity points related to river basin networks (Martín-Sotoca, 2014). References Cheng, Q. and Agterberg, F.P. (1996). Multifractal modeling and spatial statistics. Math. Geol. Vol 28, 1-16. Martín-Sotoca, J.J. (2014) Estructura Espacial de la Sequía en Pastos y sus Aplicaciones en el Seguro Agrario. Master Thesis, UPM (In Spanish). Saravia LA, Giorgi A, Momo F.: Multifractal growth in periphyton

Seasonal and spatial trends in production and stable isotope signatures of primary producers in Alberta oil sands reclamation wetlands

International Nuclear Information System (INIS)

Boutsivongsakd, M; Chen, H.; Legg, A.; Farwell, A.; Dixon, G.

2010-01-01

Oil sands processing produces large amounts of waste water that contains polycyclic aromatic hydrocarbons (PAHs) and naphthenic acids (NAs). This study investigated the effects of exposure to PAHs and NA in aquatic organisms. The carbon and nitrogen dynamics in primary producers using stable isotopes in process-affected and reference wetlands were studied. Plankton and periphytic samples from artificial wetland substrates were collected and analyzed. Periphyton was collected in 14 to 20 day intervals for 5 different time periods in 2007 and 2008 in order to analyze seasonal trends in isotopic composition. Results of the study showed d15N enriched values for some consolidated tailings (CT) at sites in 2008. Other sites with mature fine tailings (MFT) as well as non-MFT sites did not have enriched d15N values. The study suggested that there are variations in ammonia levels in the CTs of different oil sands operators. Differences in the quality of the CT resulted in differences in d15N values of the periphyton-dominated by algae as well as in the periphyton dominated by microbes.

Revisiting the functional roles of the surgeonfish Acanthurus nigrofuscus and Ctenochaetus striatus

Science.gov (United States)

Marshell, A.; Mumby, P. J.

2012-12-01

Investigating the functional role of herbivorous fish species is important for understanding reef resilience and developing targeted management plans. Among the most abundant fish species on Indo-Pacific coral reefs are the surgeonfishes Acanthurus nigrofuscus and Ctenochaetus striatus. A. nigrofuscus is an herbivorous grazer that crops filamentous algae from the epilithic algal matrix, while C. striatus is detritivorous and was thought to `brush' detritus from the surface of filamentous algae, causing little damage to algal strands. Although the foraging mechanisms and general diet of these surgeonfishes have been established, their grazing impact on epilithic algal turfs has been unclear. This is the first study to quantify the grazing impact of A. nigrofuscus and C. striatus on algal turfs. Through aquaria trials using epilithic algal turf grown on experimental tiles, we found that both A. nigrofuscus and C. striatus consistently fed more intensively upon sparse/short algal turfs even though the yield of algae per bite was greater for dense/long algal turfs. As there was no difference in the nutritional value of sparse and dense algal turfs, we hypothesise that A. nigrofuscus avoided dense turf due to its significantly greater sediment load than sparse turf, while C. striatus likely avoided dense turf as it would become entangled in their bristle-like teeth. Unexpectedly, despite its dental morphology, C. striatus removed significantly more algal turf per hour than A. nigrofuscus, irrespective of canopy height. The capability of C. striatus to remove significant quantities of algal turf through their foraging activity implies that this abundant and widespread species may substantially affect algal turf dynamics. If this is the case, the exclusion of detritivorous Ctenochaetus species from herbivorous fish functional groups used in resilience monitoring will need to be re-evaluated.

Benthic-planktonic coupling, regime shifts, and whole-lake primary production in shallow lakes.

Science.gov (United States)

Genkai-Kato, Motomi; Vadeboncoeur, Yvonne; Liboriussen, Lone; Jeppesen, Erik

2012-03-01

Alternative stable states in shallow lakes are typically characterized by submerged macrophyte (clear-water state) or phytoplankton (turbid state) dominance. However, a clear-water state may occur in eutrophic lakes even when macrophytes are absent. To test whether sediment algae could cause a regime shift in the absence of macrophytes, we developed a model of benthic (periphyton) and planktonic (phytoplankton) primary production using parameters derived from a shallow macrophyte-free lake that shifted from a turbid to a clear-water state following fish removal (biomanipulation). The model includes a negative feedback effect of periphyton on phosphorus (P) release from sediments. This in turn induces a positive feedback between phytoplankton production and P release. Scenarios incorporating a gradient of external P loading rates revealed that (1) periphyton and phytoplankton both contributed substantially to whole-lake production over a broad range of external P loading in a clear-water state; (2) during the clear-water state, the loss of benthic production was gradually replaced by phytoplankton production, leaving whole-lake production largely unchanged; (3) the responses of lakes to biomanipulation and increased external P loading were both dependent on lake morphometry; and (4) the capacity of periphyton to buffer the effects of increased external P loading and maintain a clear-water state was highly sensitive to relationships between light availability at the sediment surface and the of P release. Our model suggests a mechanism for the persistence of alternative states in shallow macrophyte-free lakes and demonstrates that regime shifts may trigger profound changes in ecosystem structure and function.

Effects of imidacloprid on the ecology of sub-tropical freshwater microcosms.

Science.gov (United States)

Sumon, Kizar Ahmed; Ritika, Afifat Khanam; Peeters, Edwin T H M; Rashid, Harunur; Bosma, Roel H; Rahman, Md Shahidur; Fatema, Mst Kaniz; Van den Brink, Paul J

2018-05-01

The neonicotinoid insecticide imidacloprid is used in Bangladesh for a variety of crop protection purposes. Imidacloprid may contaminate aquatic ecosystems via spray drift, surface runoff and ground water leaching. The present study aimed at assessing the fate and effects of imidacloprid on structural (phytoplankton, zooplankton, macroinvertebrates and periphyton) and functional (organic matter decomposition) endpoints of freshwater, sub-tropical ecosystems in Bangladesh. Imidacloprid was applied weekly to 16 freshwater microcosms (PVC tanks containing 400 L de-chlorinated tap water) at nominal concentrations of 0, 30, 300, 3000 ng/L over a period of 4 weeks. Results indicated that imidacloprid concentrations from the microcosm water column declined rapidly. Univariate and multivariate analysis showed significant effects of imidacloprid on the zooplankton and macroinvertebrate community, some individual phytoplankton taxa, and water quality variables (i.e. DO, alkalinity, ammonia and nitrate), with Cloeon sp., Diaptomus sp. and Keratella sp. being the most affected species, i.e. showing lower abundance values in all treatments compared to the control. The observed high sensitivity of Cloeon sp. and Diaptomus sp. was confirmed by the results of single species tests. No significant effects were observed on the species composition of the phytoplankton, periphyton biomass and organic matter decomposition for any of the sampling days. Our study indicates that (sub-)tropical aquatic ecosystems can be much more sensitive to imidacloprid compared to temperate ones. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

A summary of total mercury concentrations in flora and fauna near common contaminant sources in the Gulf of Mexico.

Science.gov (United States)

Lewis, M; Chancy, C

2008-02-01

Total mercury concentrations are summarized for environmental media and biota collected from near-coastal areas, several impacted by contaminant sources common to the Gulf of Mexico. Water, sediment, fish, blue crabs, oysters, clams, mussels, periphyton and seagrasses were collected during 1993-2002 from targeted areas affected by point and non-point source contaminants. Mean concentrations in water and sediment were 0.02 (+/-1 standard deviation=0.06) microg l(-1) and 96.3 (230.8) ng g(-1) dry wt, respectively. Mean total mercury concentrations in fish, blue crabs, brackish clams and mussels were significantly greater than those in sediment, seagrass, colonized periphyton and oysters. Concentrations (ng g(-1) dry wt) averaged 23.1 (two seagrass species), 220.1 (oysters), 287.8 (colonized periphyton), 604.0 (four species of freshwater mussels), 772.4 (brackish clam), 857.9 (blue crabs) and 933.1 (nine fish species). Spatial, intraspecific and interspecific variability in results limited most generalizations concerning the relative mercury contributions of different stressor types. However, concentrations were significantly greater for some biota collected from areas receiving wastewater discharges and golf course runoff (fish), agricultural runoff (oysters) and urban stormwater runoff (colonized periphyton and sediment). Marine water quality criteria and proposed sediment quality guidelines were exceeded in 1-12% of total samples. At least one seafood consumption guideline, criteria or screening value were exceeded in edible tissues of blue crabs (6% total samples) and nine fish species (8-33% total samples) but all residues were less than the US Federal Drug Administration action limit of 1.0 ppm and the few reported toxic effect concentrations available for the targeted biota.

Monitoring invasive quagga mussels, Dreissena rostriformis bugensis (Bivalvia: Dreissenidae, and other benthic organisms in a western US aqueduct

Directory of Open Access Journals (Sweden)

S. Mark Nelson

2013-01-01

Full Text Available A quagga mussel (Dreissena rostriformis bugensis Andrusov, 1897 invasion of an aqueduct in Arizona was monitored from 2007 – 2011using colonization substrates. As numbers increased, a filtering-collector caddisfly (Smicridea fasciatella McLachlan, 1871 declinedsignificantly in abundance. After two years of colonization, freshwater sponges were detected and associated with a decline in D. r. bugensisnumbers. Periphyton biomass increased considerably on substrates; perhaps partially, the result of decreased turbidity. Aqueduct biofoulerscould have major impacts on costs associated with aqueduct maintenance. From an operations viewpoint, mussels are undesirable due to flowrestriction associated with increased friction. Augmented sponge and periphyton biomass may also influence aqueduct operations andefficiencies.

Relations of biological indicators to nutrient data for lakes and streams in Pennsylvania and West Virginia, 1990-98

Science.gov (United States)

Brightbill, Robin A.; Koerkle, Edward H.

2003-01-01

The Clean Water Action Plan of 1998 provides a blueprint for federal agencies to work with states, tribes, and other stakeholders to protect and restore the Nation's water resources. The plan includes an initiative that addresses the nutrient-enrichment problem of lakes and streams across the United States. The U.S. Environmental Protection Agency (USEPA) is working to set nutrient criteria by nationwide nutrient ecoregions that are an aggregation of the Omernik level III ecoregions. Because low levels of nutrients are necessary for healthy streams and elevated concentrations can cause algal blooms that deplete available oxygen and kill off aquatic organisms, criteria levels are to be set, in part, using the relation between chlorophyll a and concentrations of total nitrogen and total phosphorus.Data from Pennsylvania and West Virginia, collected between 1990 and 1998, were analyzed for relations between chlorophyll a, nutrients, and other explanatory variables. Both phytoplankton and periphyton chlorophyll a concentrations from lakes and streams were analyzed separately within each of the USEPA nutrient ecoregions located within the boundaries of the two states. These four nutrient ecoregions are VII (Mostly Glaciated Dairy), VIII (Nutrient Poor, Largely Glaciated Upper Midwest and Northeast), IX (Southeastern Temperate Forested Plains and Hills), and XI (Central and Eastern Forested Uplands).Phytoplankton chlorophyll a concentrations in lakes were related to total nitrogen, total phosphorus, Secchi depth, concentration of dissolved oxygen, pH, water temperature, and specific conductivity. In nutrient ecoregion VII, nutrients were not significant predictors of chlorophyll a concentrations. Total nitrogen, Secchi depth, and pH were significantly related to phytoplankton chlorophyll a concentrations in nutrient ecoregion IX. Lake periphyton chlorophyll a concentrations from nutrient ecoregion XI were related to total phosphorus rather than total nitrogen, Secchi

Complex networks of functional connectivity in a wetland reconnected to its floodplain

Science.gov (United States)

Larsen, Laurel G.; Newman, Susan; Saunders, Colin; Harvey, Judson

2017-01-01

Disturbances such as fire or flood, in addition to changing the local magnitude of ecological, hydrological, or biogeochemical processes, can also change their functional connectivity—how those processes interact in space. Complex networks offer promise for quantifying functional connectivity in watersheds. The approach resolves connections between nodes in space based on statistical similarities in perturbation signals (derived from solute time series) and is sensitive to a wider range of timescales than traditional mass-balance modeling. We use this approach to test hypotheses about how fire and flood impact ecological and biogeochemical dynamics in a wetland (Everglades, FL, USA) that was reconnected to its floodplain. Reintroduction of flow pulses after decades of separation by levees fundamentally reconfigured functional connectivity networks. The most pronounced expansion was that of the calcium network, which reflects periphyton dynamics and may represent an indirect influence of elevated nutrients, despite the comparatively smaller observed expansion of phosphorus networks. With respect to several solutes, periphyton acted as a “biotic filter,” shifting perturbations in water-quality signals to different timescales through slow but persistent transformations of the biotic community. The complex-networks approach also revealed portions of the landscape that operate in fundamentally different regimes with respect to dissolved oxygen, separated by a threshold in flow velocity of 1.2 cm/s, and suggested that complete removal of canals may be needed to restore connectivity with respect to biogeochemical processes. Fire reconfigured functional connectivity networks in a manner that reflected localized burn severity, but had a larger effect on the magnitude of solute concentrations.

Epilithic algal assemblages in the Forsmark Biotest basin

Energy Technology Data Exchange (ETDEWEB)

Snoeijs, P.

1987-04-01

The Forsmark Biotest Basin is an artificial offshore brackish lake, through which the cooling water is led from the Forsmark Nuclear Power Station on the Swedish east coast. The Biotest Basin differs from the Bothnian Sea surrounding it by a temperature elevation of up to 10 degrees C, no ice cover in winter, and an artificial, fast current. At 11 sites in- and outside the basin, benthic algal assemblages on stones in the hydrolittoral belt were sampled every third week during one year. Cover abundances were estimated for all algae occurring on the stones, but for diatoms only when they formed blooms. The results of the vegetation analyses are given. Diversity indices and dominance-diversity curves were computed for each site on the basis of pooled data for the cold season and for the rest of the year. The algae included both unicellular and multicellular forms. In total 88 taxa were distinguished in the species lists: 29 Cyanophyta, 7 Rhodophyta, 1 Chrysophyceae, 9 Fucophyceae, 17 Diatomophyceae and 25 Chlorophyta. In terms of percentage cover-abundance, blue-green and green algae increased with temperature, while red and brown algae and diatoms decreased with temperature in the interval between the minimum (0 degrees C) and the maximum (25.7 degrees C) water temperatures that were measured during the investigation period. Melosira spp. and Nitzschia filiformis proved to be the diatoms most favoured by the cooling water discharge. Lower diversity and greater dominance of one or a few species over the other was caused by thermal discharge at sites with fast-flowing water, but the opposite occurred at sites with quiescent water, mainly due to a greater number and higher abundances of blue-green algal species and thread-like green algae at the latter sites. This report also gives some notes on taxonomy of the encountered species.

A comparative study of the N metabolism of phytoplankton and periphyton communities in oligotrophic lakes. Part of a coordinated programme on isotopic-tracer-aided research and monitoring on agricultural residue - biological interactions in aquatic ecosystems

International Nuclear Information System (INIS)

Goldman, C.R.

1982-08-01

Limnological research at Castle Lake, CA, and Lake Tahoe, CA-NEV, USA, during the period 1977-1982 has emphasized the effects of nutrient enrichment and deficiency on primary producers. The low ambient pools of nitrogenous nutrients and their low rates of transformation have necessitated the use of isotope tracer methods ( 14 C, 15 N, 13 N). These techniques have been used in concert with physiological assays, growth bio-assays, and whole-ecosystem nitrogen enrichments. Our most significant results, to date, include: (1) Delineation of 5 algal communities which are spatially distinct yet occur in the same lake and which differ with regard to their principal sources of N; (2) Determination of the relative affinities of the above communities for the various sources of N; (3) Demonstration of the importance of internally regenerated N to phytoplankton productivity; (4) Development of sensitive methodology to utilize the short-lived radioisotope 13 N (t1/2=10 mins) for studies of denitrification and nitrate uptake in aquatic ecosystems; (5) Comparisons of a variety of physiological assays for N-deficiency in aquatic microorganisms, involving short-term and long-term experiments in containers and in an N-enriched lake. The controlled ecosystem manipulations were intended to simulate the effects of watershed disturbance on nitrogen loading in order to more accurately evaluate their potential impacts on inorganic carbon and nitrogen assimilation by natural algal communities. Our research is an experimental approach for contrasting the strategies of planktonic and benthic algae living in the same lake but differing with regard to their principal sources of nitrogen

Year-Long Monitoring of Physico-Chemical and Biological Variables Provide a Comparative Baseline of Coral Reef Functioning in the Central Red Sea.

Science.gov (United States)

Roik, Anna; Röthig, Till; Roder, Cornelia; Ziegler, Maren; Kremb, Stephan G; Voolstra, Christian R

2016-01-01

Coral reefs in the central Red Sea are sparsely studied and in situ data on physico-chemical and key biotic variables that provide an important comparative baseline are missing. To address this gap, we simultaneously monitored three reefs along a cross-shelf gradient for an entire year over four seasons, collecting data on currents, temperature, salinity, dissolved oxygen (DO), chlorophyll-a, turbidity, inorganic nutrients, sedimentation, bacterial communities of reef water, and bacterial and algal composition of epilithic biofilms. Summer temperature (29-33°C) and salinity (39 PSU) exceeded average global maxima for coral reefs, whereas DO concentration was low (2-4 mg L-1). While temperature and salinity differences were most pronounced between seasons, DO, chlorophyll-a, turbidity, and sedimentation varied most between reefs. Similarly, biotic communities were highly dynamic between reefs and seasons. Differences in bacterial biofilms were driven by four abundant families: Rhodobacteraceae, Flavobacteriaceae, Flammeovirgaceae, and Pseudanabaenaceae. In algal biofilms, green crusts, brown crusts, and crustose coralline algae were most abundant and accounted for most of the variability of the communities. Higher bacterial diversity of biofilms coincided with increased algal cover during spring and summer. By employing multivariate matching, we identified temperature, salinity, DO, and chlorophyll-a as the main contributing physico-chemical drivers of biotic community structures. These parameters are forecast to change most with the progression of ocean warming and increased nutrient input, which suggests an effect on the recruitment of Red Sea benthic communities as a result of climate change and anthropogenic influence. In conclusion, our study provides insight into coral reef functioning in the Red Sea and a comparative baseline to support coral reef studies in the region.

Year-Long Monitoring of Physico-Chemical and Biological Variables Provide a Comparative Baseline of Coral Reef Functioning in the Central Red Sea

KAUST Repository

Roik, Anna Krystyna

2016-11-09

Coral reefs in the central Red Sea are sparsely studied and in situ data on physico-chemical and key biotic variables that provide an important comparative baseline are missing. To address this gap, we simultaneously monitored three reefs along a cross-shelf gradient for an entire year over four seasons, collecting data on currents, temperature, salinity, dissolved oxygen (DO), chlorophyll-a, turbidity, inorganic nutrients, sedimentation, bacterial communities of reef water, and bacterial and algal composition of epilithic biofilms. Summer temperature (29–33°C) and salinity (39 PSU) exceeded average global maxima for coral reefs, whereas DO concentration was low (2–4 mg L-1). While temperature and salinity differences were most pronounced between seasons, DO, chlorophyll-a, turbidity, and sedimentation varied most between reefs. Similarly, biotic communities were highly dynamic between reefs and seasons. Differences in bacterial biofilms were driven by four abundant families: Rhodobacteraceae, Flavobacteriaceae, Flammeovirgaceae, and Pseudanabaenaceae. In algal biofilms, green crusts, brown crusts, and crustose coralline algae were most abundant and accounted for most of the variability of the communities. Higher bacterial diversity of biofilms coincided with increased algal cover during spring and summer. By employing multivariate matching, we identified temperature, salinity, DO, and chlorophyll-a as the main contributing physico-chemical drivers of biotic community structures. These parameters are forecast to change most with the progression of ocean warming and increased nutrient input, which suggests an effect on the recruitment of Red Sea benthic communities as a result of climate change and anthropogenic influence. In conclusion, our study provides insight into coral reef functioning in the Red Sea and a comparative baseline to support coral reef studies in the region.

Year-Long Monitoring of Physico-Chemical and Biological Variables Provide a Comparative Baseline of Coral Reef Functioning in the Central Red Sea

KAUST Repository

Roik, Anna Krystyna; Rö thig, Till; Roder, Cornelia; Ziegler, Maren; Kremb, Stephan Georg; Voolstra, Christian R.

2016-01-01

Coral reefs in the central Red Sea are sparsely studied and in situ data on physico-chemical and key biotic variables that provide an important comparative baseline are missing. To address this gap, we simultaneously monitored three reefs along a cross-shelf gradient for an entire year over four seasons, collecting data on currents, temperature, salinity, dissolved oxygen (DO), chlorophyll-a, turbidity, inorganic nutrients, sedimentation, bacterial communities of reef water, and bacterial and algal composition of epilithic biofilms. Summer temperature (29–33°C) and salinity (39 PSU) exceeded average global maxima for coral reefs, whereas DO concentration was low (2–4 mg L-1). While temperature and salinity differences were most pronounced between seasons, DO, chlorophyll-a, turbidity, and sedimentation varied most between reefs. Similarly, biotic communities were highly dynamic between reefs and seasons. Differences in bacterial biofilms were driven by four abundant families: Rhodobacteraceae, Flavobacteriaceae, Flammeovirgaceae, and Pseudanabaenaceae. In algal biofilms, green crusts, brown crusts, and crustose coralline algae were most abundant and accounted for most of the variability of the communities. Higher bacterial diversity of biofilms coincided with increased algal cover during spring and summer. By employing multivariate matching, we identified temperature, salinity, DO, and chlorophyll-a as the main contributing physico-chemical drivers of biotic community structures. These parameters are forecast to change most with the progression of ocean warming and increased nutrient input, which suggests an effect on the recruitment of Red Sea benthic communities as a result of climate change and anthropogenic influence. In conclusion, our study provides insight into coral reef functioning in the Red Sea and a comparative baseline to support coral reef studies in the region.

Year-Long Monitoring of Physico-Chemical and Biological Variables Provide a Comparative Baseline of Coral Reef Functioning in the Central Red Sea.

Directory of Open Access Journals (Sweden)

Anna Roik

Full Text Available Coral reefs in the central Red Sea are sparsely studied and in situ data on physico-chemical and key biotic variables that provide an important comparative baseline are missing. To address this gap, we simultaneously monitored three reefs along a cross-shelf gradient for an entire year over four seasons, collecting data on currents, temperature, salinity, dissolved oxygen (DO, chlorophyll-a, turbidity, inorganic nutrients, sedimentation, bacterial communities of reef water, and bacterial and algal composition of epilithic biofilms. Summer temperature (29-33°C and salinity (39 PSU exceeded average global maxima for coral reefs, whereas DO concentration was low (2-4 mg L-1. While temperature and salinity differences were most pronounced between seasons, DO, chlorophyll-a, turbidity, and sedimentation varied most between reefs. Similarly, biotic communities were highly dynamic between reefs and seasons. Differences in bacterial biofilms were driven by four abundant families: Rhodobacteraceae, Flavobacteriaceae, Flammeovirgaceae, and Pseudanabaenaceae. In algal biofilms, green crusts, brown crusts, and crustose coralline algae were most abundant and accounted for most of the variability of the communities. Higher bacterial diversity of biofilms coincided with increased algal cover during spring and summer. By employing multivariate matching, we identified temperature, salinity, DO, and chlorophyll-a as the main contributing physico-chemical drivers of biotic community structures. These parameters are forecast to change most with the progression of ocean warming and increased nutrient input, which suggests an effect on the recruitment of Red Sea benthic communities as a result of climate change and anthropogenic influence. In conclusion, our study provides insight into coral reef functioning in the Red Sea and a comparative baseline to support coral reef studies in the region.

Mapping and spatial analysis of the distribution of indicator organisms for water quality in the stream of Ayura (Envigado, Antioquia)

International Nuclear Information System (INIS)

Guerra Rojas, Adriana; Aguirre Ramirez, Nestor Jaime; Caicedo Quintero, Orlando

2011-01-01

This research evaluates and analyzes the spatial distribution communities of periphyton and aquatic macroinvertebrates used in determining water quality, considering the work done previously by de GAIA group at the University of Antioquia on water stream Ayura. We used the functions of hydrological models preset into GIS tool, which was conducted the layout of the stream netting with. Through the overlay of thematic layers, was obtained a mapping tool that allowed us to determine the relationship between land uses given to near areas where the sampling stations were located and the population of collected organisms, they were identified at each point. The results allow us to say that, both communities of protists and aquatic macroinvertebrates as indexes established, BMWP Colombia, Dinius and INSG, show a good quality of water resources for the station 1, which are coniferous forest, high and low stubbles; in station 2, it has an acceptable quality, and it has been noticed some buildings there, pastures and monocultures; finally at station 3, located in urban areas, the water quality is lower than previous stations

Infrared and ultraviolet laser removal of crustose lichens on dolomite heritage stone

Energy Technology Data Exchange (ETDEWEB)

Sanz, Mikel; Oujja, Mohamed [Instituto de Química Física Rocasolano (IQFR), CSIC, Serrano 119, 28006 Madrid (Spain); Ascaso, Carmen; Ríos, Asunción de los; Pérez-Ortega, Sergio [Museo Nacional de Ciencia Naturales (MNCN), CSIC, Serrano 115 bis, 28006 Madrid (Spain); Souza-Egipsy, Virginia [Instituto de Ciencias Agrarias (ICA), CSIC, Serrano 115 bis, 28006 Madrid (Spain); Wierzchos, Jacek; Speranza, Mariela [Museo Nacional de Ciencia Naturales (MNCN), CSIC, Serrano 115 bis, 28006 Madrid (Spain); Cañamares, Maria Vega [Instituto de Estructura de la Materia (ICEM), CSIC, Serrano 121, 28006 Madrid (Spain); Castillejo, Marta, E-mail: marta.castillejo@iqfr.csic.es [Instituto de Química Física Rocasolano (IQFR), CSIC, Serrano 119, 28006 Madrid (Spain)

2015-08-15

Graphical abstract: - Highlights: • Laser irradiation at 1064 nm (IR) or 355 nm (UV) partially removes epilithic lichens on dolostone. • Irradiation in a sequential, dual IR–UV mode efficiently eliminates lichen thalli. • Dual IR–UV irradiation mode induces severe damage on endolithic colonizers of dolostone. - Abstract: Laser removal of biodeteriogen layers warrants detailed studies due to the advantages it brings with respect to mechanical elimination or the use of biocides. We have investigated elimination of biological crusts on dolomite stones from heritage sites in central Spain. The samples were colonized by epilithic crustose lichens of different species, such as Caloplaca sp. and Verrucaria nigrescens. A comparative study was carried out by applying infrared (1064 nm) and ultraviolet (355 nm) nanosecond laser pulses and sequences pulses of the two wavelengths using a Q-switched Nd:YAG system. To detect anatomical and ultrastructural damage to the lichens, and to assess possible morphological and chemical changes on the underlying stone induced by laser irradiation, we used stereomicroscopy, scanning electron microscopy with backscattered electron imaging and Fourier transform Raman spectroscopy. The optimal conditions for removal of the colonization crust, while ensuring preservation of the lithic substrate, were obtained for dual infrared-ultraviolet sequential irradiation.

Wastewater treatment plant effluents change abundance and composition of ammonia-oxidizing microorganisms in mediterranean urban stream biofilms.

Science.gov (United States)

Merbt, Stephanie N; Auguet, Jean-Christophe; Blesa, Alba; Martí, Eugènia; Casamayor, Emilio O

2015-01-01

Streams affected by wastewater treatment plant (WWTP) effluents are hotspots of nitrification. We analyzed the influence of WWTP inputs on the abundance, distribution, and composition of epilithic ammonia-oxidizing (AO) assemblages in five Mediterranean urban streams by qPCR and amoA gene cloning and sequencing of both archaea (AOA) and bacteria (AOB). The effluents significantly modified stream chemical parameters, and changes in longitudinal profiles of both NH(4)(+) and NO(3)(-) indicated stimulated nitrification activity. WWTP effluents were an allocthonous source of both AOA, essentially from the Nitrosotalea cluster, and mostly of AOB, mainly Nitrosomonas oligotropha, Nitrosomonas communis, and Nitrosospira spp. changing the relative abundance and the natural composition of AO assemblages. Under natural conditions, Nitrososphaera and Nitrosopumilus AOA dominated AO assemblages, and AOB were barely detected. After the WWTP perturbation, epilithic AOB increased by orders of magnitude whereas AOA did not show quantitative changes but a shift in population composition to dominance of Nitrosotalea spp. The foraneous AOB successfully settled in downstream biofilms and probably carried out most of the nitrification activity. Nitrosotalea were only observed downstream and only in biofilms exposed to either darkness or low irradiance. In addition to other potential environmental limitations for AOA distribution, this result suggests in situ photosensitivity as previously reported for Nitrosotalea under laboratory conditions.

Herbivory of Omnivorous Fish Shapes the Food Web Structure of a Chinese Tropical Eutrophic Lake: Evidence from Stable Isotope and Fish Gut Content Analyses

Directory of Open Access Journals (Sweden)

Jian Gao

2017-01-01

Full Text Available Studies suggest that, unlike the situation in temperate lakes, high biomasses of omnivorous fish are maintained in subtropical and tropical lakes when they shift from a turbid phytoplankton-dominated state to a clear water macrophyte-dominated state, and the predation pressure on large-bodied zooplankton therefore remains high. Whether this reflects a higher degree of herbivory in warm lakes than in temperate lakes is debatable. We combined food web studies using stable isotopes with gut content analyses of the most dominant fish species to elucidate similarities and differences in food web structure between a clear water macrophyte-dominated basin (MDB and a turbid phytoplankton-dominated basin (PDB of Huizhou West Lake, a shallow tropical Chinese lake. The δ13C–δ15N biplot of fish and invertebrates revealed community-wide differences in isotope-based metrics of the food webs between MDB and PDB. The range of consumer δ15N (NR was lower in MDB than in PDB, indicating shorter food web length in MDB. The mean nearest neighbor distance (MNND and standard deviation around MNND (SDNND were higher in MDB than in PDB, showing a markedly low fish trophic overlap and a more uneven packing of species in niches in MDB than in PDB. The range of fish δ13C (CR of consumers was more extensive in MDB than in PDB, indicating a wider feeding range for fish in MDB. Mixing model results showed that macrophytes and associated periphyton constituted a large fraction of basal production sources for the fish in MDB, while particulate organic matter (POM contributed a large fraction in PDB. In MDB, the diet of the dominant fish species, crucian carp (Carassius carassius, consisted mainly of vegetal matter (macrophytes and periphyton and zooplankton, while detritus was the most important food item in PDB. Our results suggest that carbon from macrophytes with associated periphyton may constitute an important food resource for omnivorous fish, and this may strongly

Detection of gametophytes in the maerl-forming species Phymatolithon calcareum (Melobesioideae, Corallinales) assessed by DNA barcoding

OpenAIRE

Peña, V; Hernandez-Kantun, J; Grall, J; Pardo, C; Lopez, L; Barbara, I; Le Gall, L; Barreiro, R

2014-01-01

Fertile gametangial plants of Phymatolithon calcareum, which are seldom reported in the Atlantic European coasts, were collected as encrusting, epilithic plants in a subtidal maerl bed in Brittany (France). Based on their morphological features, the plants were identified as P. calcareum. This identification was further confirmed by DNA barcodes using as a reference COI-5P sequences obtained from the neotype together with recent collections from the Atlantic European maerl beds. The reproduct...

On Community Education and Community Development

Directory of Open Access Journals (Sweden)

Dušana Findeisen

1996-12-01

Full Text Available In this paper Dušana Findeisen introduces community education and development. She particularly insists upon the fact that in the future our life will not be organised around a paid full time job and that we will be forced into searching other ways of getting involved into society and to acquire our social identity. Community education is one of the ways we could eventually choose. Since community development education in Slovenia has not developed yet the author begins by describing some basic concepts like community and history of community education and community development movement. Further on, she introduces the Andragogical Summer School based in a small Slovenian town, its aim being to encourage Slovenian adult educators to encourage community development projects.

Phosphorus cycling and partitioning in an oligotrophic Everglades wetland ecosystem: A radioisotope tracing study

Science.gov (United States)

Noe, G.B.; Scinto, L.J.; Taylor, J.; Childers, D.L.; Jones, R.D.

2003-01-01

1. Our goal was to quantify short-term phosphorus (P) partitioning and identify the ecosystem components important to P cycling in wetland ecosystems. To do this, we added P radiotracer to oligotrophic, P-limited Everglades marshes. 32PO4 was added to the water column in six 1-m2 enclosed mesocosms located in long-hydroperiod marshes of Shark River Slough, Everglades National Park. Ecosystem components were then repeatedly sampled over 18 days. 2. Water column particulates (>0.45 ??m) incorporated radiotracer within the first minute after dosing and stored 95-99% of total water column 32P activity throughout the study. Soluble (<0.45 ??m) 32P in the water column, in contrast, was always <5% of the 32P in surface water. Periphyton, both floating and attached to emergent macrophytes, had the highest specific activity of 32P (Bq g-131P) among the different ecosystem components. Fish and aquatic macroinvertebrates also had high affinity for P, whereas emergent macrophytes, soil and flocculent detrital organic matter (floc) had the lowest specific activities of radiotracer. 3. Within the calcareous, floating periphyton mats, 81% of the initial 32P uptake was associated with Ca, but most of this 32P entered and remained within the organic pool (Ca-associated = 14% of total) after 1 day. In the floc layer, 32P rapidly entered the microbial pool and the labile fraction was negligible for most of the study. 4. Budgeting of the radiotracer indicated that 32P moved from particulates in the water column to periphyton and floc and then to the floc and soil over the course of the 18 days incubations. Floc (35% of total) and soil (27%) dominated 32P storage after 18 days, with floating periphyton (12%) and surface water (10%) holding smaller proportions of total ecosystem 32P. 5. To summarise, oligotrophic Everglades marshes exhibited rapid uptake and retention of labile 32P. Components dominated by microbes appear to control short-term P cycling in this oligotrophic ecosystem.

Developing Learning Communities: Using Communities of Practice within Community Psychology

Science.gov (United States)

Lawthom, Rebecca

2011-01-01

The idea that communities need to be inclusive is almost axiomatic. The process, whereby, community members engage in inclusive practices is far less understood. Similarly, UK universities are being encouraged to include the wider community and extent campus boundaries. Here, I suggest a particular theoretical lens which sheds light on engagement…

Leveraging disjoint communities for detecting overlapping community structure

International Nuclear Information System (INIS)

Chakraborty, Tanmoy

2015-01-01

Network communities represent mesoscopic structure for understanding the organization of real-world networks, where nodes often belong to multiple communities and form overlapping community structure in the network. Due to non-triviality in finding the exact boundary of such overlapping communities, this problem has become challenging, and therefore huge effort has been devoted to detect overlapping communities from the network.In this paper, we present PVOC (Permanence based Vertex-replication algorithm for Overlapping Community detection), a two-stage framework to detect overlapping community structure. We build on a novel observation that non-overlapping community structure detected by a standard disjoint community detection algorithm from a network has high resemblance with its actual overlapping community structure, except the overlapping part. Based on this observation, we posit that there is perhaps no need of building yet another overlapping community finding algorithm; but one can efficiently manipulate the output of any existing disjoint community finding algorithm to obtain the required overlapping structure. We propose a new post-processing technique that by combining with any existing disjoint community detection algorithm, can suitably process each vertex using a new vertex-based metric, called permanence, and thereby finds out overlapping candidates with their community memberships. Experimental results on both synthetic and large real-world networks show that PVOC significantly outperforms six state-of-the-art overlapping community detection algorithms in terms of high similarity of the output with the ground-truth structure. Thus our framework not only finds meaningful overlapping communities from the network, but also allows us to put an end to the constant effort of building yet another overlapping community detection algorithm. (paper)

Quality of Streams in Johnson County, Kansas, and Relations to Environmental Variables, 2003-07

Science.gov (United States)

Rasmussen, Teresa J.; Poulton, Barry C.; Graham, Jennifer L.

2009-01-01

The quality of streams and relations to environmental variables in Johnson County, northeastern Kansas, were evaluated using water, streambed sediment, land use, streamflow, habitat, algal periphyton (benthic algae), and benthic macroinvertebrate data. Water, streambed sediment, and macroinvertebrate samples were collected in March 2007 during base flow at 20 stream sites that represent 11 different watersheds in the county. In addition, algal periphyton samples were collected twice (spring and summer 2007) at one-half of the sites. Environmental data including water and streambed-sediment chemistry data (primarily nutrients, fecal-indicator bacteria, and organic wastewater compounds), land use, streamflow, and habitat data were used in statistical analyses to evaluate relations between biological conditions and variables that may affect them. This report includes an evaluation of water and streambed-sediment chemistry, assessment of habitat conditions, comparison of biological community attributes (such as composition, diversity, and abundance) among sampling sites, placement of sampling sites into impairment categories, evaluation of biological data relative to environmental variables, and evaluation of changes in biological communities and effects of urbanization. This evaluation is useful for understanding factors that affect stream quality, for improving water-quality management programs, and for documenting changing conditions over time. The information will become increasingly important for protecting streams in the future as urbanization continues. Results of this study indicate that the biological quality at nearly all biological sampling sites in Johnson County has some level of impairment. Periphyton taxa generally were indicative of somewhat degraded conditions with small to moderate amounts of organic enrichment. Camp Branch in the Blue River watershed was the only site that met State criteria for full support of aquatic life in 2007. Since 2003

WASP7 BENTHIC ALGAE - MODEL THEORY AND USER'S GUIDE

Science.gov (United States)

The standard WASP7 eutrophication module includes nitrogen and phosphorus cycling, dissolved oxygen-organic matter interactions, and phytoplankton kinetics. In many shallow streams and rivers, however, the attached algae (benthic algae, or periphyton, attached to submerged substr...

Creating Learning Communities: An Introduction to Community Education.

Science.gov (United States)

Decker, Larry E.; Boo, Mary Richardson

Schools cannot succeed without collaboration with parents and the community. Defining community education as active community involvement in the education of children, this booklet describes aspects of community education. Community education, the booklet points out, can take place at physical locations such as formal school buildings, which lie…

Fixation and long-term accumulation of tritium from tritiated water in an experimental aquatic environment

International Nuclear Information System (INIS)

Strand, J.A.; Templeton, W.L.; Olson, P.A.

1975-01-01

The accumulation of tritium in selected freshwater biota was studied in a 10 m diameter concrete-lined pond at the Hanford Atomic Energy Works. Tritium as tritiated water was introduced for 8 months continuously in the replacement water at a concentration of μCi per liter; and water, biota (carp, clams, crayfish, periphyton, pondweed), and sediments were sampled on a predetermined schedule. The pond was maintained on uncontaminated replacement waters for an additional 8 months to determine the rate of elimination from the ecosystem. After the first day, tissue-free-water tritium in all biota approached an equilibrium with pond water. Final concentration factors of 0.89, 0.87, 0.82, 0.92, 0.77, 0.88 were calculated for carp, clam, crayfish, snail, periphyton, and pondweed. Although highly variable, analyses of pond sediments suggested an initial rapid uptake by the loose water fraction, attaining 0.30 of the pond equilibrium level in three days. There was evidence to suggest a secondary slower rate of uptake that accounted for 0.65 of the pond equilibrium level as determined at seven months. Tissue-bond tritium initially increased rapidly in all biota sampled, but slowed with time. Equilibrium conditions were not reached. Final concentration factors for carp, clam, crayfish, snail, periphyton, and pondweed were calculated to be 0.49, 0.10, 0.53, 0.54, 0.15, and 0.62. Analyses of sediments after removal of the loose water fraction revealed little or no organically bound tritium

A SUMMARY OF TOTAL MERCURY CONCENTRATIONS IN FLORA AND FAUNA NEAR CONTAMINANT SOURCES IN THE GULF OF MEXICO

Science.gov (United States)

This report summarizes total mercury concentrations for environmental media collected from near-coastal areas including those impacted by contaminant sources common to the Gulf of Mexico. Water, sediment, fish, blue crabs, oysters, clams, mussels, periphyton and seagrasses were ...

Urban Effects on Microbial Processes and Food Webs in Coastal Watershed Streams

Science.gov (United States)

We conducted a stream survey in the Narragansett Bay Watershed that targeted a gradient of development intensity and examined how associated changes in nutrients, carbon, and stressors affected periphyton and macroinvertebrates. Concentrations of nutrients, cations, and anions we...

Algoflora of oxbow ponds transformed with beavers' activity

OpenAIRE

Макаревич, Т. А.; Белоус, В. В.; Гурчунова, Т. А.

2016-01-01

Algoflora of oxbow ponds transformed with beaver activity is characterized by high species richness and taxonomic diversity, high periphyton importance in the formation of algoflora compared with phytoplankton, prevalence of periphytic and benthic algae over typically planktonic forms

Rediscovering community: Interethnic relationships and community gardening

Directory of Open Access Journals (Sweden)

August John Hoffman

2010-11-01

Full Text Available Community service work, volunteerism and mentoring have recently become popular topics of research as effective methods in improving self-esteem and civic responsibility. In the current study we explored the relationship between participation in a community service gardening program and ethnocentrism. We hypothesised that an inverse correlation would emerge where students who participated in a community service-gardening program would increase their perceptions of the importance of community service work and decrease their scores in ethnocentrism. Results of the paired samples t-test strongly support the hypothesis that community service gardening work significantly reduces reports of ethnocentrism: t(10 = -2.52, (p < .03 for community college students. The ramifications of the study and ramifications for future research are offered.

Lichen flora of Tomaszow Mazowiecki

Energy Technology Data Exchange (ETDEWEB)

Rydzak, J; Krysiak, K

1970-01-01

In Tomaszow Mazowiecki, a small town in Poland with the air highly contaminated with gases (SO/sub 2/, CS/sub 2/, H/sub 2/S), a flora of epiphytic and epilithic lichens is present. Lichens are not indicators of air pollution. They are indicators of a complex of microclimatic conditions that enable them to maintain a positive balance of assimilation and of respiratory processes in a given station within the town as well as in natural habitats. 58 references, 16 figures, 7 tables.

Hydrological, morphometrical, and biological characteristics of the connecting rivers of the International Great Lakes: a review

Science.gov (United States)

Edwards, Clayton J.; Hudson, Patrick L.; Duffy, Walter G.; Nepszy, Stephen J.; McNabb, Clarence D.; Haas, Robert C.; Liston, Charles R.; Manny, Bruce; Busch, Wolf-Dieter N.; Dodge, D.P.

1989-01-01

The connecting channels of the Great Lakes are large rivers (1, 200-9, 900 m3 • s-1) with limited tributary drainage systems and relatively stable hydrology (about 2:1 ration of maximum to minimum flow). The rivers, from headwaters to outlet, are the St. Marys, St. Clair, Detroit, Niagara, and St. Lawrence. They share several characteristics with certain other large rivers: the fish stocks that historically congregated for spawning or feeding have been overfished, extensive channel modification have been made, and they have been used as a repository for domestic and industrial wastes and for hydroelectric energy generation. Levels of phosphorus, chlorophyll a, and particulate organic matter increase 3- to 5-fold from the St. Marys River to the St. Lawrence River. Biological communities dependent on nutrients in the water column, such as phytoplankton, periphyton, and zooplankton similarly increase progressively downstream through the system. The standing crop of emergent macrophytes is similar in all of the rivers, reflecting the relatively large nutrient pools in the sediments and atmosphere. Consequently, emergent macrophytes are an important source of organic matter (67% of total primary production) in the nutrient poor waters of the St. Marys River, whereas phytoplankton production dominates (76%) in the enriched St. Lawrence River. Submersed and emergent macrophytes and the associated periphyton are major producers of organic matter in the connecting channels. Another major source of organic matter (measured as ash free dry weight, AFDW) in the Detroit River is sewage, introduced at a rate of 26, 000 t per year. The production of benthos ranges from a low 5.4 g AFDW•m-2 in the Detroit River to a high of 15.5 g AFDW•m-2 in the St. Marys River. The rivers lack the organic transport from riparian sources upstream but receive large amounts of high quality phytoplankton and zooplankton from the Great Lakes.

A hundred years of the phycological research in lednice ponds - the impact of the environmental conditions on the development of cyanobacteria and algae

Czech Academy of Sciences Publication Activity Database

Kopp, Radovan; Skácelová, O.; Heteša, J.; Marvan, P.; Bešta, T.; Zapomělová, Eliška; Straková, Lucie; Bohunická, Markéta

2012-01-01

Roč. 97, sp. iss.1 (2012), s. 3-87 ISSN 1211-8788 Institutional research plan: CEZ:AV0Z60050516 Institutional support: RVO:67985939 ; RVO:60077344 Keywords : phytoplankton * periphyton * ponds Subject RIV: EF - Botanics; DA - Hydrology ; Limnology (BC-A)

Plant pigment types, distributions, and influences on shallow water submerged aquatic vegetation mapping

Science.gov (United States)

Hall, Carlton R.; Bostater, Charles R., Jr.; Virnstein, Robert

2004-11-01

Development of robust protocols for use in mapping shallow water habitats using hyperspectral imagery requires knowledge of absorbing and scattering features present in the environment. These include, but are not limited to, water quality parameters, phytoplankton concentrations and species, submerged aquatic vegetation (SAV) species and densities, epiphytic growth on SAV, benthic microalgae and substrate reflectance characteristics. In the Indian River Lagoon, Fl. USA we conceptualize the system as having three possible basic layers, water column and SAV bed above the bottom. Each layer is occupied by plants with their associated light absorbing pigments that occur in varying proportions and concentrations. Phytoplankton communities are composed primarily of diatoms, dinoflagellates, and picoplanktonic cyanobacteria. SAV beds, including flowering plants and green, red, and brown macro-algae exist along density gradients ranging in coverage from 0-100%. SAV beds may be monotypic, or more typically, mixtures of the several species that may or may not be covered in epiphytes. Shallow water benthic substrates are colonized by periphyton communities that include diatoms, dinoflagellates, chlorophytes and cyanobacteria. Inflection spectra created form ASIA hyperspectral data display a combination of features related to water and select plant pigment absorption peaks.

Assessing Community Informatics: A Review of Methodological Approaches for Evaluating Community Networks and Community Technology Centers.

Science.gov (United States)

O'Neil, Dara

2002-01-01

Analyzes the emerging community informatics evaluation literature to develop an understanding of the indicators used to gauge project impacts in community networks and community technology centers. The study finds that community networks and community technology center assessments fall into five key areas: strong democracy; social capital;…

Genetic diversity and distribution of periphytic Synechococcus spp. in biofilms and picoplankton of Lake Constance

NARCIS (Netherlands)

Becker, S.; Singh, A.K.; Postius, C.; Böger, P.; Ernst, A.

2004-01-01

In various water depths of the littoral zone of Lake Constance (Bodensee) cyanobacteria of the Synechococcus-type were isolated from biofilms (periphyton) on three natural substrates and an artificial one (unglazed tiles). From one tile three strains of phycoerythrin (PE)-rich Synechococcus spp.

Integrating Community into the Classroom: Community Gardening, Community Involvement, and Project-Based Learning.

Science.gov (United States)

Langhout, Regina Day; Rappaport, Julian; Simmons, Doretha

2002-01-01

Culturally relevant, ongoing project-based learning was facilitated in a predominantly African American urban elementary school via a community garden project. The project involved teachers, students, university members, and community members. This article evaluates the project through two classroom-community collaboration models, noting common…

Study of methylation sites and factors in contaminated aquatic systems in the Amazon using an optimized radiochemical technique. Highlights and achievements

International Nuclear Information System (INIS)

Davee Guimaraes, Jean Remy

2002-01-01

Full text: Highlights and achievements: We confirmed that high methylation potentials (up to 22%) are found in roots of Paspalum repens and other floating macrophyte species such as Eichhomia crassipes and Ludwigia helmynthoryza during both phases of the hydrological cycle, with a tendency for higher values in the wet season, confirming findings of previous studies, and a strong intra and interlake variation. Hg methylation in macrophyte roots is carried out mainly in the root-associated periphyton a complex and variable assemblage of benthic microalgae, fungi, bacteria and organic and inorganic detritus. However, no significant correlation was found in the first campaign between Hg methylation in samples of Paspalum sp. roots and the amount of periphyton in these samples. We also verified that total plankton and phytoplankton are sites of a low 203 Hg; Basic infrastructure problems caused partial loss of samples in one of the campaigns. (author)

Community Mentoring: A Tool for Successful Communities

Science.gov (United States)

Dodge, Kathryn E.

2015-01-01

Mentoring occurs in an ad hoc and largely invisible manner in communities. This mentoring happens through modeling, storytelling, and asking open-ended questions. If Extension specialists and agents were more conscious and intentional about teaching community members and leaders about community mentoring, they would be more successful in resolving…

Coastal Upwelling Drives Intertidal Assemblage Structure and Trophic Ecology.

Science.gov (United States)

Reddin, Carl J; Docmac, Felipe; O'Connor, Nessa E; Bothwell, John H; Harrod, Chris

2015-01-01

Similar environmental driving forces can produce similarity among geographically distant ecosystems. Coastal oceanic upwelling, for example, has been associated with elevated biomass and abundance patterns of certain functional groups, e.g., corticated macroalgae. In the upwelling system of Northern Chile, we examined measures of intertidal macrobenthic composition, structure and trophic ecology across eighteen shores varying in their proximity to two coastal upwelling centres, in a hierarchical sampling design (spatial scales of >1 and >10 km). The influence of coastal upwelling on intertidal communities was confirmed by the stable isotope values (δ13C and δ15N) of consumers, including a dominant suspension feeder, grazers, and their putative resources of POM, epilithic biofilm, and macroalgae. We highlight the utility of muscle δ15N from the suspension feeding mussel, Perumytilus purpuratus, as a proxy for upwelling, supported by satellite data and previous studies. Where possible, we used corrections for broader-scale trends, spatial autocorrelation, ontogenetic dietary shifts and spatial baseline isotopic variation prior to analysis. Our results showed macroalgal assemblage composition, and benthic consumer assemblage structure, varied significantly with the intertidal influence of coastal upwelling, especially contrasting bays and coastal headlands. Coastal topography also separated differences in consumer resource use. This suggested that coastal upwelling, itself driven by coastline topography, influences intertidal communities by advecting nearshore phytoplankton populations offshore and cooling coastal water temperatures. We recommend the isotopic values of benthic organisms, specifically long-lived suspension feeders, as in situ alternatives to offshore measurements of upwelling influence.

Response of Submerged Macrophyte Communities to External and Internal Restoration Measures in North Temperate Shallow Lakes

Science.gov (United States)

Hilt, Sabine; Alirangues Nuñez, Marta M.; Bakker, Elisabeth S.; Blindow, Irmgard; Davidson, Thomas A.; Gillefalk, Mikael; Hansson, Lars-Anders; Janse, Jan H.; Janssen, Annette B. G.; Jeppesen, Erik; Kabus, Timm; Kelly, Andrea; Köhler, Jan; Lauridsen, Torben L.; Mooij, Wolf M.; Noordhuis, Ruurd; Phillips, Geoff; Rücker, Jacqueline; Schuster, Hans-Heinrich; Søndergaard, Martin; Teurlincx, Sven; van de Weyer, Klaus; van Donk, Ellen; Waterstraat, Arno; Willby, Nigel; Sayer, Carl D.

2018-01-01

Submerged macrophytes play a key role in north temperate shallow lakes by stabilizing clear-water conditions. Eutrophication has resulted in macrophyte loss and shifts to turbid conditions in many lakes. Considerable efforts have been devoted to shallow lake restoration in many countries, but long-term success depends on a stable recovery of submerged macrophytes. However, recovery patterns vary widely and remain to be fully understood. We hypothesize that reduced external nutrient loading leads to an intermediate recovery state with clear spring and turbid summer conditions similar to the pattern described for eutrophication. In contrast, lake internal restoration measures can result in transient clear-water conditions both in spring and summer and reversals to turbid conditions. Furthermore, we hypothesize that these contrasting restoration measures result in different macrophyte species composition, with added implications for seasonal dynamics due to differences in plant traits. To test these hypotheses, we analyzed data on water quality and submerged macrophytes from 49 north temperate shallow lakes that were in a turbid state and subjected to restoration measures. To study the dynamics of macrophytes during nutrient load reduction, we adapted the ecosystem model PCLake. Our survey and model simulations revealed the existence of an intermediate recovery state upon reduced external nutrient loading, characterized by spring clear-water phases and turbid summers, whereas internal lake restoration measures often resulted in clear-water conditions in spring and summer with returns to turbid conditions after some years. External and internal lake restoration measures resulted in different macrophyte communities. The intermediate recovery state following reduced nutrient loading is characterized by a few macrophyte species (mainly pondweeds) that can resist wave action allowing survival in shallow areas, germinate early in spring, have energy-rich vegetative

Response of Submerged Macrophyte Communities to External and Internal Restoration Measures in North Temperate Shallow Lakes.

Science.gov (United States)

Hilt, Sabine; Alirangues Nuñez, Marta M; Bakker, Elisabeth S; Blindow, Irmgard; Davidson, Thomas A; Gillefalk, Mikael; Hansson, Lars-Anders; Janse, Jan H; Janssen, Annette B G; Jeppesen, Erik; Kabus, Timm; Kelly, Andrea; Köhler, Jan; Lauridsen, Torben L; Mooij, Wolf M; Noordhuis, Ruurd; Phillips, Geoff; Rücker, Jacqueline; Schuster, Hans-Heinrich; Søndergaard, Martin; Teurlincx, Sven; van de Weyer, Klaus; van Donk, Ellen; Waterstraat, Arno; Willby, Nigel; Sayer, Carl D

2018-01-01

Submerged macrophytes play a key role in north temperate shallow lakes by stabilizing clear-water conditions. Eutrophication has resulted in macrophyte loss and shifts to turbid conditions in many lakes. Considerable efforts have been devoted to shallow lake restoration in many countries, but long-term success depends on a stable recovery of submerged macrophytes. However, recovery patterns vary widely and remain to be fully understood. We hypothesize that reduced external nutrient loading leads to an intermediate recovery state with clear spring and turbid summer conditions similar to the pattern described for eutrophication. In contrast, lake internal restoration measures can result in transient clear-water conditions both in spring and summer and reversals to turbid conditions. Furthermore, we hypothesize that these contrasting restoration measures result in different macrophyte species composition, with added implications for seasonal dynamics due to differences in plant traits. To test these hypotheses, we analyzed data on water quality and submerged macrophytes from 49 north temperate shallow lakes that were in a turbid state and subjected to restoration measures. To study the dynamics of macrophytes during nutrient load reduction, we adapted the ecosystem model PCLake. Our survey and model simulations revealed the existence of an intermediate recovery state upon reduced external nutrient loading, characterized by spring clear-water phases and turbid summers, whereas internal lake restoration measures often resulted in clear-water conditions in spring and summer with returns to turbid conditions after some years. External and internal lake restoration measures resulted in different macrophyte communities. The intermediate recovery state following reduced nutrient loading is characterized by a few macrophyte species (mainly pondweeds) that can resist wave action allowing survival in shallow areas, germinate early in spring, have energy-rich vegetative

Community empowerment and community cohesion: parallel agendas for community building in England?

Directory of Open Access Journals (Sweden)

Marjorie Mayo

2009-02-01

Full Text Available Community empowerment and community capacity building have been central to government agendas in Britain over the past decade. Agendas for tackling the so-called ‘War on Terrorism’ and promoting community cohesion have become increasingly significant in addition, especially since the bombings in London in 2005. This article focuses upon the current gap between these differing agendas. This is particularly relevant in an era of increasing globalisation, with considerable debate on the impact of migration, and anxieties about previous approaches to multiculturalism that have been the subject of growing criticism. Having set out these gaps in public policy and research in this field, the article examines the evidence from research, including 100 interviews together with focus groups conducted in three localities in England, identifying the problems, in terms of the lack of engagement of ‘new communities’ and in terms of the potential tensions within and between communities. There was, however, encouraging evidence that strategies were being developed to develop more inclusive, more democratically accountable and more effective forms of community engagement. The article concludes by summarising potential implications for building community cohesion and social solidarity.

Enhancing Community Service Learning Via Practical Learning Communities

Directory of Open Access Journals (Sweden)

Ilana Ronen

2015-02-01

Full Text Available The advantages of learning communities focused on analyzing social issues and educational repercussions in the field are presented in this study. The research examines the contribution of a learning community to enhancing student teachers' responsibility and their social involvement. The assumption was that participating in learning community would further implement student teachers' community social involvement while enhancing responsibility in their field of action. A questionnaire aimed to present the student teachers' attitudes involving all aspects of studying in the learning community and their social activity in the community was conducted. The findings pinpointed that there were positive contributions of the learning communities from a personal aspect such as developing self-learning, and learning about “me”, as well as broaden their teaching skills, through methodology for teacher training, and developing reflective thought. These insights can also be implemented in various educational frameworks and during service learning as part of teacher training.

Communities matter: Institutional preconditions for community renewable energy

International Nuclear Information System (INIS)

Wirth, Steffen

2014-01-01

Energy transitions are high on political agendas. From a practical viewpoint, community approaches are deemed essential in order to transition from a predominantly centralized energy supply to a decentralized one, and to exploit the potential of renewable energies. In this paper, I discuss how the emergence of community-based energy projects can be analyzed from an institutional perspective. In this context, a ‘community’ is treated as an individual institutional order that shapes decisions. I examine how community structures the implementation of biogas cooperatives in the Autonomous Province of South Tyrol in Northern Italy. My findings suggest that ‘community spirit’, a cooperative tradition, and the norms of locality and responsibility are central drivers behind the emergence and constitution of biogas cooperatives. Not only do these institutional features of community influence the decision concerning which farmers are in or out but also plant location and scale. I argue that ‘community’ is a necessary analytical category for understanding community energy. - Highlights: • I analyze the emergence and constitution of biogas cooperatives in South Tyrol. • Emerging processes and the principal constitutions are similar. • Institutional forces influenced the biogas cooperatives' emergence and constitution. • Biogas cooperatives are decisively shaped by community spirit and local tradition. • The concept of community is used as an explanatory category for community energy

Community Economics

OpenAIRE

武藤, 宣道; Nobumichi, MUTOH

2000-01-01

This paper examines the new field of community economics with respect to Japan. A number of studies in community economics have already been produced in OECD countries including the United States. Although these are of great interest, each country has its own historical, socioeconomic context and must therefore develop its own approach to community economics. Community-oriented economics is neither macro-nor micro-economics in the standard economics textbook sense. Most community economics st...

Community gardens: lessons learned from California Healthy Cities and Communities.

Science.gov (United States)

Twiss, Joan; Dickinson, Joy; Duma, Shirley; Kleinman, Tanya; Paulsen, Heather; Rilveria, Liz

2003-09-01

Community gardens enhance nutrition and physical activity and promote the role of public health in improving quality of life. Opportunities to organize around other issues and build social capital also emerge through community gardens. California Healthy Cities and Communities (CHCC) promotes an inclusionary and systems approach to improving community health. CHCC has funded community-based nutrition and physical activity programs in several cities. Successful community gardens were developed by many cities incorporating local leadership and resources, volunteers and community partners, and skills-building opportunities for participants. Through community garden initiatives, cities have enacted policies for interim land and complimentary water use, improved access to produce, elevated public consciousness about public health, created culturally appropriate educational and training materials, and strengthened community building skills.

Keeping "Community" in a Community Land Trust

Science.gov (United States)

Gray, Karen A.; Galande, Mugdha

2011-01-01

This instrumental case study examined the role of grassroots community organizing in a community land trust (CLT) in a southern U.S. city. Twenty-nine homeowners, renters, board members, community members, and current and former CLT employees were interviewed. In addition, two focus groups of 11 and six participants composed of CLT residents and…

Community Health Warriors: Marshallese Community Health Workers' Perceptions and Experiences with CBPR and Community Engagement.

Science.gov (United States)

Purvis, Rachel S; Bing, Williamina Ioanna; Jacob, Christopher J; Lang, Sharlynn; Mamis, Sammie; Ritok, Mandy; Rubon-Chutaro, Jellesen; McElfish, Pearl Anna

2017-01-01

Our manuscript highlights the viewpoints and reflections of the native Marshallese community health workers (CHWs) engaged in research with the local Marshallese community in Northwest Arkansas. In particular, this paper documents the vital role Marshallese CHWs play in the success of programs and research efforts. The negative health effects of nuclear testing in the Marshall Islands has been passed down through many generations, along with unfavorable attitudes toward the U.S. government and researchers. However, the community-based participatory research (CBPR) approach used by the University of Arkansas for Medical Sciences (UAMS) has allowed the native Marshallese CHWs to become advocates for the Marshallese community. The use of native CHWs has also leveled the power dynamics that can be a barrier to community-based research, and has strengthened trust with community stakeholders. Our paper shows how using Marshallese CHWs can produce positive health outcomes for the Marshallese community.

Remarks on the occurrence and ecology of several interesting cyanobacterial morphospecies found in South Moravian wetlands

Czech Academy of Sciences Publication Activity Database

Skácelová, O.; Zapomělová, Eliška

2010-01-01

Roč. 95, č. 1 (2010), s. 201-221 ISSN 1211-8788 R&D Projects: GA ČR(CZ) GAP504/10/1501 Institutional research plan: CEZ:AV0Z60170517 Keywords : cyanobacteria * floristics * ecology * phytoplankton * periphyton * metaphyton * phytobentos Subject RIV: DA - Hydrology ; Limnology

Response of small-stream biota to sudden flow pulses following extreme precipitation events

Czech Academy of Sciences Publication Activity Database

Adámek, Z.; Konečná, J.; Podhrázská, J.; Všetičková, Lucie; Jurajdová, Zdenka

2016-01-01

Roč. 25, č. 2 (2016), s. 495-501 ISSN 1230-1485 R&D Projects: GA ČR GBP505/12/G112 Institutional support: RVO:68081766 Keywords : discharge rate * brook * macrozoobenthos * periphyton * fish Subject RIV: EH - Ecology, Behaviour Impact factor: 0.793, year: 2016

Evaluating Community-Based Participatory Research to Improve Community-Partnered Science and Community Health

Science.gov (United States)

Hicks, Sarah; Duran, Bonnie; Wallerstein, Nina; Avila, Magdalena; Belone, Lorenda; Lucero, Julie; Magarati, Maya; Mainer, Elana; Martin, Diane; Muhammad, Michael; Oetzel, John; Pearson, Cynthia; Sahota, Puneet; Simonds, Vanessa; Sussman, Andrew; Tafoya, Greg; Hat, Emily White

2013-01-01

Background Since 2007, the National Congress of American Indians (NCAI) Policy Research Center (PRC) has partnered with the Universities of New Mexico and Washington to study the science of community-based participatory research (CBPR). Our goal is to identify facilitators and barriers to effective community–academic partnerships in American Indian and other communities, which face health disparities. Objectives We have described herein the scientific design of our National Institutes of Health (NIH)-funded study (2009–2013) and lessons learned by having a strong community partner leading the research efforts. Methods The research team is implementing a mixed-methods study involving a survey of principal investigators (PIs) and partners across the nation and in-depth case studies of CBPR projects. Results We present preliminary findings on methods and measures for community-engaged research and eight lessons learned thus far regarding partnership evaluation, advisory councils, historical trust, research capacity development of community partner, advocacy, honoring each other, messaging, and funding. Conclusions Study methodologies and lessons learned can help community–academic research partnerships translate research in communities. PMID:22982842

Effects of the antibiotic enrofloxacin on the ecology of tropical eutrophic freshwater microcosms.

Science.gov (United States)

Rico, Andreu; Dimitrov, Mauricio R; Van Wijngaarden, René P A; Satapornvanit, Kriengkrai; Smidt, Hauke; Van den Brink, Paul J

2014-02-01

The main objective of the present study was to assess the ecological impacts of the fluoroquinolone antibiotic enrofloxacin on the structure and functioning of tropical freshwater ecosystems. Enrofloxacin was applied at a concentration of 1, 10, 100 and 1,000 μg/L for 7 consecutive days in 600-L outdoor microcosms in Thailand. The ecosystem-level effects of enrofloxacin were monitored on five structural (macroinvertebrates, zooplankton, phytoplankton, periphyton and bacteria) and two functional (organic matter decomposition and nitrogen cycling) endpoint groups for 4 weeks after the last antibiotic application. Enrofloxacin was found to dissipate relatively fast from the water column (half-dissipation time: 11.7h), and about 11% of the applied dose was transformed into its main by-product ciprofloxacin after 24h. Consistent treatment-related effects on the invertebrate and primary producer communities and on organic matter decomposition could not be demonstrated. Enrofloxacin significantly affected the structure of leaf-associated bacterial communities at the highest treatment level, and reduced the abundance of ammonia-oxidizing bacteria and ammonia-oxidizing archaea in the sediments, with calculated NOECs of 10 and enrofloxacin are not likely to result in direct or indirect toxic effects on the invertebrate and primary producer communities, nor on important microbially mediated functions such as nitrification. Copyright © 2014 Elsevier B.V. All rights reserved.

Dispersal Ability Determines the Role of Environmental, Spatial and Temporal Drivers of Metacommunity Structure

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Padial, André A.; Ceschin, Fernanda; Declerck, Steven A. J.; De Meester, Luc; Bonecker, Cláudia C.; Lansac-Tôha, Fabio A.; Rodrigues, Liliana; Rodrigues, Luzia C.; Train, Sueli; Velho, Luiz F. M.; Bini, Luis M.

2014-01-01

Recently, community ecologists are focusing on the relative importance of local environmental factors and proxies to dispersal limitation to explain spatial variation in community structure. Albeit less explored, temporal processes may also be important in explaining species composition variation in metacommunities occupying dynamic systems. We aimed to evaluate the relative role of environmental, spatial and temporal variables on the metacommunity structure of different organism groups in the Upper Paraná River floodplain (Brazil). We used data on macrophytes, fish, benthic macroinvertebrates, zooplankton, periphyton, and phytoplankton collected in up to 36 habitats during a total of eight sampling campaigns over two years. According to variation partitioning results, the importance of predictors varied among biological groups. Spatial predictors were particularly important for organisms with comparatively lower dispersal ability, such as aquatic macrophytes and fish. On the other hand, environmental predictors were particularly important for organisms with high dispersal ability, such as microalgae, indicating the importance of species sorting processes in shaping the community structure of these organisms. The importance of watercourse distances increased when spatial variables were the main predictors of metacommunity structure. The contribution of temporal predictors was low. Our results emphasize the strength of a trait-based analysis and of better defining spatial variables. More importantly, they supported the view that “all-or- nothing” interpretations on the mechanisms structuring metacommunities are rather the exception than the rule. PMID:25340577

Community Identity and User Engagement in a Multi-Community Landscape.

Science.gov (United States)

Zhang, Justine; Hamilton, William L; Danescu-Niculescu-Mizil, Cristian; Jurafsky, Dan; Leskovec, Jure

2017-05-01

A community's identity defines and shapes its internal dynamics. Our current understanding of this interplay is mostly limited to glimpses gathered from isolated studies of individual communities. In this work we provide a systematic exploration of the nature of this relation across a wide variety of online communities. To this end we introduce a quantitative, language-based typology reflecting two key aspects of a community's identity: how distinctive , and how temporally dynamic it is. By mapping almost 300 Reddit communities into the landscape induced by this typology, we reveal regularities in how patterns of user engagement vary with the characteristics of a community. Our results suggest that the way new and existing users engage with a community depends strongly and systematically on the nature of the collective identity it fosters, in ways that are highly consequential to community maintainers. For example, communities with distinctive and highly dynamic identities are more likely to retain their users. However, such niche communities also exhibit much larger acculturation gaps between existing users and newcomers, which potentially hinder the integration of the latter. More generally, our methodology reveals differences in how various social phenomena manifest across communities, and shows that structuring the multi-community landscape can lead to a better understanding of the systematic nature of this diversity.

Structural and successional variability of periphytic algal community in a Amazonian lake during the dry and rainy season (Rio Branco, Acre Variação estrutural e sucessional da comunidade de algas perifíticas em lago amazônico durante o período seco e chuvoso

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Raquel C.S França

2011-01-01

Full Text Available The colonization process and successional patterns of a periphytic algal community were evaluated in a Amazonian Viveiro Lake (Rio Branco, Acre, Brazil. Sampling was performed over a period of 35 days; at four-day intervals for 20 days, and then at five-day intervals. Water sampling for physical, chemical and biological analyses was done during the dry and rainy season. Glass slides were used as artificial substrates for periphyton colonization. The structural community was evaluated through population density, algae class, diversity indices and descriptive species. Species richness, diversity and evenness increased as succession progressed. While density of Bacillariophyceae, Euglenophyceae and Zygnemaphyceae increased with succession, Cyanobacteria remained dominant. Synechocystis aquatilis, Synechocystis diplococcus and Navicula pseudolanceolata were the main descriptive species in both the dry and rainy season. Cymbela tumida, Frustulia rhomboides, Trachelomonas lacustris and Closterium acicularis was correlated with an increase in hydrologic level during the rainy season. Conversely, the density of Chlamydomonas sp., Chroomonas nordstedtii, Trachelomonas volvocinopsis, Trachelomonas volvocina and Synechococcus linearis was correlated with an increase in water transparency during the dry season. In general, the periphytic algal community showed high diversity and species richness independent of season. Season also had little influence on representation of algae class and main descriptive species. However, successional patterns varied by season, and changes in hydrologic levels acted directly on the succession path of periphytic algae. More research on periphyton dynamics is needed to improve our understanding of tropical lake ecosystems, especially in Amazonian.A colonização e o modelo sucessional da comunidade de algas perifíticas foram avaliados no amazônico Lago do Viveiro (Rio Branco, Acre, Brasil. Amostragens foram realizadas no per

Sequencing type material resolves the identity and distribution of the generitype Lithophyllum incrustans, and related European species L. hibernicum and L. bathyporum (Corallinales, Rhodophyta).

Science.gov (United States)

Hernandez-Kantun, Jazmin J; Rindi, Fabio; Adey, Walter H; Heesch, Svenja; Peña, Viviana; Le Gall, Line; Gabrielson, Paul W

2015-08-01

DNA sequences from type material in the nongeniculate coralline genus Lithophyllum were used to unambiguously link some European species names to field-collected specimens, thus providing a great advance over morpho-anatomical identifi-cation. In particular, sequence comparisons of rbcL, COI and psbA genes from field-collected specimens allowed the following conclusion: the generitype species, L. incrustans, occurs mostly as subtidal rhodoliths and crusts on both Atlantic and Mediterranean coasts, and not as the common, NE Atlantic, epilithic, intertidal crust reported in the literature. The heterotypic type material of L. hibernicum was narrowed to one rhodolith belonging in Lithophyllum. As well as occurring as a subtidal rhodolith, L. hibernicum is a common, epilithic and epizoic crust in the intertidal zone from Ireland south to Mediterranean France. A set of four features distinguished L. incrustans from L. hibernicum, including epithallial cell diameter, pore canal shape of sporangial conceptacles and sporangium height and diameter. An rbcL sequence of the lectotype of Lithophyllum bathyporum, which was recently proposed to accommodate Atlantic intertidal collections of L. incrustans, corresponded to a distinct taxon hitherto known only from Brittany as the subtidal, bisporangial, lectotype, but also occurs intertidally in Atlantic Spain. Specimens from Ireland and France morpho-anatomically identified as L. fasciculatum and a specimen from Cornwall likewise identified as L. duckerae were resolved as L. incrustans and L. hibernicum, respectively. © 2015 Phycological Society of America.

Community Psychology and Community Mental Health: A Call for Reengagement.

Science.gov (United States)

Townley, Greg; Brown, Molly; Sylvestre, John

2018-03-01

Community psychology is rooted in community mental health research and practice and has made important contributions to this field. Yet, in the decades since its inception, community psychology has reduced its focus on promoting mental health, well-being, and liberation of individuals with serious mental illnesses. This special issue endeavors to highlight current efforts in community mental health from our field and related disciplines and point to future directions for reengagement in this area. The issue includes 12 articles authored by diverse stakeholder groups. Following a review of the state of community mental health scholarship in the field's two primary journals since 1973, the remaining articles center on four thematic areas: (a) the community experience of individuals with serious mental illness; (b) the utility of a participatory and cross-cultural lens in our engagement with community mental health; (c) Housing First implementation, evaluation, and dissemination; and (d) emerging or under-examined topics. In reflection, we conclude with a series of challenges for community psychologists involved in future, transformative, movements in community mental health. © Society for Community Research and Action 2018.

Evaluating Community Partnerships Addressing Community Resilience in Los Angeles, California

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Malcolm V. Williams

2018-03-01

Full Text Available Community resilience has grown in importance in national disaster response and recovery efforts. However, measurement of community resilience, particularly the content and quality of relationships aimed at improving resilience, is lacking. To address this gap, we used a social network survey to measure the number, type, and quality of relationships among organizations participating in 16 coalitions brought together to address community resilience in the Los Angeles Community Disaster Resilience project. These coalitions were randomized to one of two approaches (community resilience or preparedness. Resilience coalitions received training and support to develop these partnerships and implement new activities. Both coalition types received expert facilitation by a public health nurse or community educator. We also measured the activities each coalition engaged in and the extent to which partners participated in these activities at two time points. We found that the community resilience coalitions were initially larger and had lower trust among members than the preparedness communities. Over time, these trust differences dissipated. While both coalitions grew, the resilience community coalitions maintained their size difference throughout the project. We also found differences in the types of activities implemented by the resilience communities; these differences were directly related to the trainings provided. This information is useful to organizations seeking guidance on expanding the network of community-based organizations that participate in community resilience activities.

Recovery of benthic algal assemblages from acidification: how long does it take, and is there a link to eutrophication?

Czech Academy of Sciences Publication Activity Database

Schneider, S. C.; Oulehle, Filip; Krám, Pavel; Hruška, Jakub

2018-01-01

Roč. 805, č. 1 (2018), s. 33-47 ISSN 0018-8158 R&D Projects: GA ČR(CZ) GA15-08124S Keywords : Benthic algae * Multiple stressors * Periphyton * pH * Stream Subject RIV: DA - Hydrology ; Limnology OBOR OECD: Water resources Impact factor: 2.056, year: 2016

Persistent effects of acidification on stream ecosystem structure and function

Czech Academy of Sciences Publication Activity Database

Traister, E.; McDowell, W. H.; Krám, Pavel; Fottová, Daniela; Kolaříková, K.

2013-01-01

Roč. 32, č. 2 (2013), s. 586-596 ISSN 2161-9565 R&D Projects: GA MŠk(CZ) ED1.1.00/02.0073 Institutional support: RVO:67179843 Keywords : acidification * macroinvertebrates * whole-stream metabolism * streams * isotopic signature * terrestrial detritus * periphyton * GEOMON Subject RIV: EH - Ecology, Behaviour

[Community Nutrition].

Science.gov (United States)

Aranceta, Javier

2004-06-01

In the last 20 years, Public Health Nutrition focused mainly on the qualitative aspects which may influence the onset of chronic diseases, quality of life, physical and mental performance and life expectancy. This applied knowledge organised as part of preventive and health promotion programs led to the development of Community Nutrition. The aim of Community Nutrition actions is to adequate lifestyles related to food consumption patterns in order to improve the quality of life and contribute to health promotion of the population in the community where programs and services are delivered. Key functions to develop in a Community Nutrition Unit consist in the identification and assessment of nutrition problems in the community as well as the design, implementation and evaluation of intervention programs by means of appropriate strategies. These should aim at different populations groups and settings, such as work places, schools, high risk groups or the general public. Nowadays, Community Nutrition work efforts should focus on three main aspects: nutrition education in schools and in the community; food safety and food security and the development and reinforcement of food preparation skills across all age groups. Social catering services, either in schools, the work place or at the community level, need to ensure adequate nutritional supply, provide foods contributing to healthy eating practices as well as to enhance culinary traditions and social learning. Food safety and food security have become a top priority in Public Health. The concepts referes to the availability of food safe and adequate as well as in sufficient amount in order to satisfy nutrition requirements of all individuals in the community. Social changes along new scientific developments will introduce new demands in Community Nutrition work and individual dietary counselling will become a key strategy. In order to face new challenges, community nutrition pactitioners require a high quality

The Entrepreneurial Community College: Bringing Workforce, Economic and Community Development to Virginia Community Colleges.

Science.gov (United States)

Drury, Richard L.

2001-01-01

Proposes creating an entrepreneurial college within the community college that will offer non-credit courses to the community and workforce. States that the courses would focus on the training needs of community industry, with the employer as the customer, rather than the student. Adds that the proposed college would also focus on community…

Characterization of the Kootenai River Algae Community and Primary Productivity Before and After Experimental Nutrient Addition, 2004–2007 [Chapter 2, Kootenai River Algal Community Characterization, 2009 KTOI REPORT].

Energy Technology Data Exchange (ETDEWEB)

Holderman, Charlie [Kootenai Tribe of Idaho; Bonners Ferry, ID; Anders, Paul [Cramer Fish Sciences; Moscow, ID; Shafii, Bahman [Statistical Consulting Services; Clarkston, WA

2009-07-01

, and a meandering reach. The study design included 14 sampling sites: an upstream, unimpounded reference site (KR-14), four control (non-fertilized) canyon sites downstream from Libby Dam, but upstream from nutrient addition (KR-10 through KR-13), two treatment sites referred to collectively as the nutrient addition zone (KR-9 and KR-9.1, located at and 5 km downstream from the nutrient addition site), two braided reach sites (KR-6 and KR-7), and four meander reach sites (KR-1 through KR-4). A series of qualitative evaluations and quantitative analyses were used to assess baseline conditions and effects of experimental nutrient addition treatments on chlorophyll, primary productivity, and taxonomic composition and metric arrays for the diatom and green algae communities. Insufficient density in the samples precluded analyses of bluegreen algae taxa and metrics for pre- and post-nutrient addition periods. Chlorophyll a concentration (mg/m{sup 2}), chlorophyll accrual rate (mg/m{sup 2}/30d), total chlorophyll concentration (chlorophyll a and b) (mg/m{sup 2}), and total chlorophyll accrual rate (mg/m{sup 2}/30d) were calculated. Algal taxa were identified and grouped by taxonomic order as Cyanophyta (blue-greens), Chlorophyta (greens), Bacillariophyta (diatoms), Chrysophyta (goldens), and dominant species from each sample site were identified. Algal densities (number/ml) in periphyton samples were calculated for each sample site and sampling date. Principal Component Analysis (PCA) was performed to reduce the dimension of diatom and algae data and to determine which taxonomic groups and metrics were contributing significantly to the observed variation. PCA analyses were tabulated to indicate eigenvalues, proportion, and cumulative percent variation, as well as eigenvectors (loadings) for each of the components. Biplot graphic displays of PCA axes were also generated to characterize the pattern and structure of the underlying variation. Taxonomic data and a series of

ALGAE PROLIFERATION ON SUBSTRATES IMMERSED IN BIOLOGICALLY TREATED SEWAGE

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Tomasz Garbowski

2017-01-01

Full Text Available Due fast biomass production, high affinity for N and P and possibilities to CO2 sequestration microalgae are currently in the spotlight, especially in renewable energy technologies sector. The majority of studies focus their attention on microalgae cultivation with respect to biomass production. Fuel produced from algal biomass can contribute to reducing consumption of conventional fossil fuels and be a remedy for a rising energy crisis and global warming induced by air pollution. Some authors opt for possibilities of using sewage as a nutrient medium in algae cultivation. Other scientists go one step further and present concepts to introduce microalgal systems as an integral part of wastewater treatment plants. High costs of different microalgal harvesting methods caused introduction of the idea of algae immobilization in a form of periphyton on artificial substrates. In the present study the attention has focused on possibilities of using waste materials as substrates to proliferation of periphyton in biologically treated sewage that contained certain amounts of nitrogen and phosphorus.

Dissolved organic carbon concentration controls benthic primary production: results from in situ chambers in north-temperate lakes

Science.gov (United States)

Godwin, Sean C.; Jones, Stuart E.; Weidel, Brian C.; Solomon, Christopher T.

2014-01-01

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.

THE INFLUENCE OF SUBMERGED MACROPHYTES ON SEDIMENTARY DIATOM ASSEMBLAGES(1).

Science.gov (United States)

Vermaire, Jesse C; Prairie, Yves T; Gregory-Eaves, Irene

2011-12-01

Submerged macrophytes are a central component of lake ecosystems; however, little is known regarding their long-term response to environmental change. We have examined the potential of diatoms as indicators of past macrophyte biomass. We first sampled periphyton to determine whether habitat was a predictor of diatom assemblage. We then sampled 41 lakes in Quebec, Canada, to evaluate whether whole-lake submerged macrophyte biomass (BiomEpiV) influenced surface sediment diatom assemblages. A multivariate regression tree (MRT) was used to construct a semiquantitative model to reconstruct past macrophyte biomass. We determined that periphytic diatom assemblages on macrophytes were significantly different from those on wood and rocks (ANOSIM R = 0.63, P macrophyte, nutrient-limited lakes (BiomEpiV ≥525 μg · L(-1) ; total phosphorus [TP] macrophyte, nutrient-limited lakes (BiomEpiV macrophytes have a significant influence on diatom community structure and that sedimentary diatom assemblages can be used to infer past macrophyte abundance. © 2011 Phycological Society of America.

Preliminary methodological proposal for estimating environmental flows in projects approved by the ministry of environment and sustainable development (MADS), Colombia

International Nuclear Information System (INIS)

Pinilla Agudelo, Gabriel A; Rodriguez Sandoval, Erasmo A; Camacho Botero, Luis A

2014-01-01

A methodological proposal for estimating environmental flows in large projects approved by Agencia Nacional de Licencias Ambientales (ANLA) in Colombian rivers was developed. The project is the result of an agreement between the MADS and the Universidad Nacional de Colombia, Bogota (UNC). The proposed method begins with an evaluation of hydrological criteria, continues with a hydraulic and water quality validation, and follows with the determination of habitat integrity. This is an iterative process that compares conditions before and after the project construction and allows to obtain the magnitude of a monthly flow that, besides preserving the ecological functions of the river, guarantees the water uses downstream. Regarding to the biotic component, the proposal includes the establishment and monitoring of biotic integrity indices for four aquatic communities (periphyton, macro invertebrates, riparian vegetation, and fish). The effects that flow reduction may produce in the medium and long term can be assessed by these indices. We present the results of applying the methodology to several projects licensed by the MADS.

Towards Community - Reflections on Community Psychiatry, Culture and Alterity

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Ana Neto

2015-06-01

Full Text Available Introduction: The constant transformation of  communities  and  its relationship  with mental illness has been studied and debated for the past decades, although it is still not clear how it has been incorporated in clinical practice.Aims: The authors propose to review the relevance to Psychiatry, especially Community Psychiatry, of understanding  communities as well as the methodologies and conceptual frameworks that allow that approach.Methods: Selected and critical review of the literature about Community Psychiatry and Culture, Communities, and Social Inequity and Mental Health.Results: The authors start by reviewing the meaning  of  Community and the  defining principles of Community Psychiatry in their relationships with  cultural  sensitivity.  This aspect is illustrated with two examples of the impact of culture and alterity in the understanding of Mental Health and Service Organization, one at the level of International and Global Mental Health, and the other at the local communities’ level. In this context, participatory action research is highlighted.Conclusions: Psychiatry,  in  particular Community  Psychiatry,  by acknowledging a  wide  range  of  methodologies  and  being open  to transdisciplinary  models, is in a privileged position of electing communities as a field of investigation and integrate it in its praxis.

Bayesian community detection

DEFF Research Database (Denmark)

Mørup, Morten; Schmidt, Mikkel N

2012-01-01

Many networks of scientific interest naturally decompose into clusters or communities with comparatively fewer external than internal links; however, current Bayesian models of network communities do not exert this intuitive notion of communities. We formulate a nonparametric Bayesian model...... for community detection consistent with an intuitive definition of communities and present a Markov chain Monte Carlo procedure for inferring the community structure. A Matlab toolbox with the proposed inference procedure is available for download. On synthetic and real networks, our model detects communities...... consistent with ground truth, and on real networks, it outperforms existing approaches in predicting missing links. This suggests that community structure is an important structural property of networks that should be explicitly modeled....

Community development planning

International Nuclear Information System (INIS)

Gray, S.I.

1983-01-01

The focus of this paper will be methods of local community involvement in the community development planning efforts which will be required at the recommended sites. Community development planning will include capital improvement plans, housing plans, zoning changes, business development plans and other community service and fiscal plans required to meet the projected needs of new residents as a result of the repository construction and operation. This paper will present, (1) the need for community planning, (2) methods of responding to community planning needs, (3) current community planning issues to be addressed. 2 references, 1 figure

Community

Science.gov (United States)

stability Science & Innovation Collaboration Careers Community Environment Science & Innovation Recruitment Events Community Commitment Giving Campaigns, Drives Economic Development Employee Funded neighbor pledge: contribute to quality of life in Northern New Mexico through economic development

Community-Based Programming: An Opportunity and Imperative for the Community College.

Science.gov (United States)

Boone, Edgar J.

1992-01-01

Defines community-based programing as a cooperative process in which the community college serves as leader and catalyst in effecting collaboration among community members, leaders, and groups. Recommends 15 tasks for community college leaders involved in community-based programing, including environmental scanning and coalition building. (DMM)

Claiming Community

DEFF Research Database (Denmark)

Jensen, Steffen Bo

As its point of departure this working paper takes the multitude of different uses and meanings of the concept of community in local politics in Cape Town. Instead of attempting to define it in substantive terms, the paper takes a social constructivist approach to the study of community...... is termed community work. First, the paper explores how community has become a governmental strategy, employed by the apartheid regime as well, although in different ways, as post-apartheid local government. Secondly, the paper explores the ways in which community becomes the means in which local residents...... lay claim on the state, as well as how it enters into local power struggles between different political groups within the township. In the third part, the paper explores how the meanings of community and the struggles to realise it have changed as South Africa, nationally and locally, has become...

Community relations

International Nuclear Information System (INIS)

O'Neil, C.

1997-01-01

The interaction of the oil and gas companies with the Northern communities regarding drilling activities was an important aspect of oil and gas operations conducted in the Beaufort Sea. During the 1960s the industry and aboriginal people basically ignored each other. Later, the industry put more emphasis on community consultation until finally two-way communication was established. Respect for the land and the environment were very important to aboriginal people who depended on the land and its resources for their traditional way of life. Community relations policies by the various companies involved in the area, and the impact they have had on their respective communities were recounted. Not all efforts were successful, however, the companies and the communities learned from their experiences, and by the time operations ceased, the communities seemed to be more appreciative of the ways they were being treated by the oil companies. 22 figs

Community Involvement in School: Social Relationships in a Bedroom Community

Science.gov (United States)

Preston, Jane P.

2013-01-01

The purpose of this qualitative case study was to describe how community involvement in school is associated with the social relationships existing/lacking within a bedroom community. Thirty-five interviews with school council members, teachers, and community members highlighted that traditional forms of community involvement in school generate…

Community capacity building and sustainability: outcomes of community-based participatory research.

Science.gov (United States)

Hacker, Karen; Tendulkar, Shalini A; Rideout, Catlin; Bhuiya, Nazmim; Trinh-Shevrin, Chau; Savage, Clara P; Grullon, Milagro; Strelnick, Hal; Leung, Carolyn; DiGirolamo, Ann

2012-01-01

For communities, the value of community-based participatory research (CBPR) is often manifested in the outcomes of increased capacity and sustainable adoption of evidence-based practices for social change. Educational opportunities that promote discourse between community and academic partners can help to advance CBPR and better define these outcomes. This paper describes a community-academic conference to develop shared definitions of community capacity building and sustainability related to CBPR and to identify obstacles and facilitators to both. "Taking It to the Curbside: Engaging Communities to Create Sustainable Change for Health" was planned by five Clinical Translational Science Institutes and four community organizations. After a keynote presentation, breakout groups of community and academic members met to define community capacity building and sustainability, and to identify facilitators and barriers to achieving both. Groups were facilitated by researcher-community partner teams and conversations were recorded and transcribed. Qualitative analysis for thematic content was conducted by a subset of the planning committee. Important findings included learning that (1) the concepts of capacity and sustainability were considered interconnected; (2) partnership was perceived as both a facilitator and an outcome of CBPR; (3) sustainability was linked to "transfer of knowledge" from one generation to another within a community; and (4) capacity and sustainability were enhanced when goals were shared and health outcomes were achieved. Community capacity building and sustainability are key outcomes of CBPR for communities. Co-learning opportunities that engage and mutually educate both community members and academics can be useful strategies for identifying meaningful strategies to achieve these outcomes.

University-Community Research Partnership for Community ...

African Journals Online (AJOL)

This paper analyses the existing university–community partnership in research in Tanzania and proposes a bottom-top model instead of the traditional top-bottom approach which works with perceived needs of communities rather than real needs. Given their core missions, many universities assume that they achieve their ...

From Community to Meta-Community Mental Health Care

Directory of Open Access Journals (Sweden)

Nick Bouras

2018-04-01

Full Text Available Since the 1960s, we have witnessed the development and growth of community mental health care that continues to dominate mental health policy and practice. Several high-income countries have implemented community mental health care programmes but for many others, including mostly low- and middle-income countries, it remains an aspiration. Although community mental health care has been positive for many service users, it has also had severe shortcomings. Expectations that it would lead to fuller social integration have not been fulfilled and many service users remain secluded in sheltered or custodial environments with limited social contacts and no prospect of work. Others receive little or no service at all. In today’s complex landscape of increasingly specialised services for people with mental health problems, the number of possible interfaces between services is increasing. Together with existing uneven financing systems and a context of constant change, these interfaces are challenging us to develop effective care pathways adjusted to the needs of service users and their carers. This discussion paper reviews the developments in community mental health care over the recent years and puts forward the concept of “Meta-Community Mental Health Care”. “Meta-Community Mental Health Care” embraces pluralism in understanding and treating psychiatric disorders, acknowledges the complexities of community provision, and reflects the realities and needs of the current era of care.

Biclique communities

DEFF Research Database (Denmark)

Jørgensen, Sune Lehmann; Hansen-Schwartz, Martin; Hansen, Lars Kai

2008-01-01

We present a method for detecting communities in bipartite networks. Based on an extension of the k-clique community detection algorithm, we demonstrate how modular structure in bipartite networks presents itself as overlapping bicliques. If bipartite information is available, the biclique...... community detection algorithm retains all of the advantages of the k-clique algorithm, but avoids discarding important structural information when performing a one-mode projection of the network. Further, the biclique community detection algorithm provides a level of flexibility by incorporating independent...

Community gardening: a parsimonious path to individual, community, and environmental resilience.

Science.gov (United States)

Okvat, Heather A; Zautra, Alex J

2011-06-01

The goal of this paper is to introduce community gardening as a promising method of furthering well-being and resilience on multiple levels: individual, social group, and natural environment. We examine empirical evidence for the benefits of gardening, and we advocate the development and testing of social ecological models of community resilience through examination of the impact of community gardens, especially in urban areas. The definition of community is extended beyond human social ties to include connections with other species and the earth itself, what Berry (1988) has called an Earth community. We discuss the potential contribution of an extensive network of community gardens to easing the global climate change crisis and address the role of community psychologists in community gardening research and policy-oriented action.

The Chinese community patient’s life satisfaction, assessment of community medical service, and trust in community health delivery system

Science.gov (United States)

2013-01-01

Background Although the Chinese government put a lot of effort into promoting the community patient’s life satisfaction, there still lacked the holistic and systematic approaches to promote the community patient’s life satisfaction in various regions of China. On the basis of the literature, it was found that both the community patient’s assessment of community medical service and trust in community health delivery system were important considerations when the community patient comprehensively evaluated community medical service to generate life satisfaction. So this study was set up to test whether and to what extent the community patient’s assessments of various major aspects of community medical service/various major aspects of the community patient’s trust in community health delivery system influenced life satisfaction in whole China/in various regions of China. Methods In order to explore the situation of China’s community health delivery system before 2009 and provide a reference for China’s community health delivery system reform, the data that could comprehensively and accurately reflect the community patient’s life satisfaction, assessment of community medical service, and trust in community health delivery system in various regions of China was needed, so this study collaborated with the National Bureau of Statistics of China to carry out a large-scale 2008 national community resident household survey (N = 3,306) for the first time in China. And the specified ordered probit models were established to analyze the dataset from this household survey. Results Among major aspects of community medical service, the medical cost (particularly in developed regions), the doctor-patient communication (particularly in developed regions), the medical facility and hospital environment (particularly in developed regions), and the medical treatment process (particularly in underdeveloped regions) were all key considerations (ppatient’s life

The Los Angeles County Community Disaster Resilience Project — A Community-Level, Public Health Initiative to Build Community Disaster Resilience

Directory of Open Access Journals (Sweden)

David Eisenman

2014-08-01

Full Text Available Public health officials need evidence-based methods for improving community disaster resilience and strategies for measuring results. This methods paper describes how one public health department is addressing this problem. This paper provides a detailed description of the theoretical rationale, intervention design and novel evaluation of the Los Angeles County Community Disaster Resilience Project (LACCDR, a public health program for increasing community disaster resilience. The LACCDR Project utilizes a pretest–posttest method with control group design. Sixteen communities in Los Angeles County were selected and randomly assigned to the experimental community resilience group or the comparison group. Community coalitions in the experimental group receive training from a public health nurse trained in community resilience in a toolkit developed for the project. The toolkit is grounded in theory and uses multiple components to address education, community engagement, community and individual self-sufficiency, and partnerships among community organizations and governmental agencies. The comparison communities receive training in traditional disaster preparedness topics of disaster supplies and emergency communication plans. Outcome indicators include longitudinal changes in inter-organizational linkages among community organizations, community member responses in table-top exercises, and changes in household level community resilience behaviors and attitudes. The LACCDR Project is a significant opportunity and effort to operationalize and meaningfully measure factors and strategies to increase community resilience. This paper is intended to provide public health and academic researchers with new tools to conduct their community resilience programs and evaluation research. Results are not yet available and will be presented in future reports.

Assessing Community Leadership: Understanding Community Capacity for Health Improvement.

Science.gov (United States)

Castle, Billie; Wendel, Monica; Kelly Pryor, Brandy N; Ingram, Monique

The purpose of this study was to pilot a quantitative instrument to measure aspects of community leadership within an assessment framework. The instrument includes 14 Likert-type questions asking residents how they perceive leaders within 5 sectors: Louisville Metro Council/Mayor's Office, the faith community, education, business, and the civic sector. Louisville/Jefferson County, Kentucky, has a population of about 743 000 residents. Respondents were asked to examine leadership within West Louisville, an economically deprived area of the city made up of 9 contiguous neighborhoods. This area is predominantly African American (78% compared with 22% in Louisville Metro), with an overall poverty rate of 43% (compared with 18% in Louisville Metro), and unemployment rate of 23% (compared with 8% in Louisville Metro). Residents of West Louisville are looking to leadership to address many of the inequities. Twenty-seven participants representing 7 community sectors completed the survey, of whom 90% work in West Louisville. The instrument measured local perceptions of leadership strength, effectiveness, trust, communication, community building, and leadership development. The majority of respondents agree that strong leadership exists across the 5 sectors, with variation regarding perceptions of the quality of that leadership. City leadership within the Mayor's Office and Metro Council is largely viewed positively, while the growing tensions within the education sector were reflected in the survey results. The perception of community leadership is important to understanding local community capacity to improve health and also inclusivity of community voice in the assessment and community improvement processes. Results from such assessments can offer useful information for strengthening community capacity and sustaining relationships needed to enact progressive and equitable solutions to address local issues. Leaders in a variety of settings can utilize this instrument to

State-Level Community Benefit Regulation and Nonprofit Hospitals' Provision of Community Benefits.

Science.gov (United States)

Singh, Simone R; Young, Gary J; Loomer, Lacey; Madison, Kristin

2018-04-01

Do nonprofit hospitals provide enough community benefits to justify their tax exemptions? States have sought to enhance nonprofit hospitals' accountability and oversight through regulation, including requirements to report community benefits, conduct community health needs assessments, provide minimum levels of community benefits, and adhere to minimum income eligibility standards for charity care. However, little research has assessed these regulations' impact on community benefits. Using 2009-11 Internal Revenue Service data on community benefit spending for more than eighteen hundred hospitals and the Hilltop Institute's data on community benefit regulation, we investigated the relationship between these four types of regulation and the level and types of hospital-provided community benefits. Our multivariate regression analyses showed that only community health needs assessments were consistently associated with greater community benefit spending. The results for reporting and minimum spending requirements were mixed, while minimum income eligibility standards for charity care were unrelated to community benefit spending. State adoption of multiple types of regulation was consistently associated with higher levels of hospital-provided community benefits, possibly because regulatory intensity conveys a strong signal to the hospital community that more spending is expected. This study can inform efforts to design regulations that will encourage hospitals to provide community benefits consistent with policy makers' goals. Copyright © 2018 by Duke University Press.

Role of Community Radio for Community Development in Bangladesh

Directory of Open Access Journals (Sweden)

Md. Anowarul Arif Khan

2017-04-01

Full Text Available Community radio is a medium of expressing and sharing views, thoughts, ideas, problems and prospects of rural, disadvantaged, vulnerable and hard to reach population with the mainstream population. As the media of root level people of the disadvantaged areas, Community radio has become popular in recent years and it has opened a new arena for both the policy makers as well as grassroots people to be involved in the development process of their community. There are about 17 Community Radios broadcasting 135 hours programmes in a day across the country. The Community Radio can help us in addressing social, economic, cultural, educational, health, water and sanitation and disaster related issues more effectively and strategically. In order to highlight the importance and effectiveness of community radio for the community development of Bangladesh, this study has been conducted based on the secondary data. This is a group effort that has become successful by the co-operation of many individuals and institutions. Access to Information (a2i Programme would like to express sincere gratitude to Monisha Mohonto, Project Focal and Bakul Mohonto, Program Assistant, BTV for introducing such an innovative project. As this is a new concept, there is no significant study has been conducted. Therefore the study has been directed to explore the importance of community FM radio in Bangladesh particularly in remote and rural areas.

Best practices for community gardening in a US-Mexico border community.

Science.gov (United States)

Mangadu, Thenral; Kelly, Michael; Orezzoli, Max C E; Gallegos, Rebecca; Matharasi, Pracheta

2017-12-01

Minority communities such as those on the US-Mexico border are placed at disproportionate high risk for child and adult obesity, diabetes and cardiovascular diseases. A built environment characterized by an arid desert climate, lack of access to healthy foods, barriers to increasing physical activity, cultural and community norms which deter healthy eating and sustainable food production, shape obesity-related health disparities in these communities. Three pilot community gardens (implemented by two local governmental organizations and one community-based organization) were funded through the local Healthy Eating Active Living (HEAL) initiative in El Paso, Texas, and Las Cruces and Anthony, New Mexico (US-MX border communities with high obesity rates) in order to encourage healthy lifestyles among families in the region. A mixed-methods evaluation (n = 223) examined the implementation process, immediate outcomes and best practices of implementing and sustaining community gardens in these minority binational communities. In addition to nutrition-related outcomes, the potential for psychosocial outcomes from participating in community and school garden projects were observed. The best practices in relation to (i) assessing community norms related to growing food, (ii) increasing access to land and water for community/school gardening and (iii) enhancing social support for gardening are discussed. The implications of these best practices for obesity prevention and implementing community gardens in a minority US-MX border community characterized by cultural, geographical and socioeconomic barriers are examined. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

European Community.

Science.gov (United States)

1987-05-01

The European Community was established in 1951 to reconcile France and Germany after World War II and to make possible the eventual federation of Europe. By 1986, there were 12 member countries: France, Italy, Belgium, the Federal Republic of Germany, Luxembourg, the Netherlands, Denmark, Ireland, the United Kingdom, Greece, Spain, and Portugal. Principal areas of concern are internal and external trade, agriculture, monetary coordination, fisheries, common industrial and commercial policies, assistance, science and research, and common social and regional policies. The European Community has a budget of US$34.035 billion/year, funded by customs duties and 1.4% of each member's value-added tax. The treaties establishing the European Community call for members to form a common market, a common customs tariff, and common agricultural, transport, economic, and nuclear policies. Major European Community institutions include the Commission, Council of Ministers, European Parliament, Court of Justice, and Economic and Social Committee. The Community is the world's largest trading unit, accounting for 15% of world trade. The 2 main goals of the Community's industrial policy are to create an open internal market and to promote technological innovation in order to improve international competitiveness. The European Community aims to contribute to the economic and social development of Third World countries as well.

Aquatic biology studies

International Nuclear Information System (INIS)

Anon.

1976-01-01

Aquatic biology studies focused on studying the hydrothermal effects of Par Pond reservoir on periphyton, plankton, zooplankton, macrophytes, human pathogens, and microbial activity; the variability between the artificial streams of the Flowing Streams Laboratory and Upper Three Runs Creek; and the bacterial production of methane in Savannah River Plant aquatic systems

Community Drive

DEFF Research Database (Denmark)

Magnussen, Rikke

2018-01-01

Schools and educational institutions are challenged by not adequately educating students for independent knowledge collaboration and solving of complex societal challenges (Bundsgaard & Hansen, 2016; Slot et al., 2017). As an alternative strategy to formal learning has Community-driven research...... opportunity to break boundaries between research institutions and surrounding communities through the involvement of new types of actors, knowledge forms and institutions (OECD, 2011). This paper presents the project Community Drive a three year cross disciplinary community-driven game– and data-based project....... In the paper we present how the project Community Drive initiated in May 2018 is based on results from pilot projects conducted from 2014 – 2017. Overall these studies showed that it is a strong motivational factor for students to be given the task to change their living conditions through redesign...

Community Capitals as Community Resilience to Climate Change: Conceptual Connections

Directory of Open Access Journals (Sweden)

Shaikh Mohammad Kais

2016-12-01

Full Text Available In the last few decades, disaster risk reduction programs and climate initiatives across the globe have focused largely on the intimate connections between vulnerability, recovery, adaptation, and coping mechanisms. Recent focus, however, is increasingly paid to community resilience. Community, placed at the intersection between the household and national levels of social organization, is crucial in addressing economic, social, or environmental disturbances disrupting human security. Resilience measures a community’s capability of bouncing back—restoring the original pre-disaster state, as well as bouncing forward—the capacity to cope with emerging post-disaster situations and changes. Both the ‘bouncing back’ and ‘moving forward’ properties of a community are shaped and reshaped by internal and external shocks such as climate threats, the community’s resilience dimensions, and the intensity of economic, social, and other community capitals. This article reviews (1 the concept of resilience in relation to climate change and vulnerability; and (2 emerging perspectives on community-level impacts of climate change, resilience dimensions, and community capitals. It argues that overall resilience of a place-based community is located at the intersection of the community’s resilience dimensions, community capitals, and the level of climate disruptions.

Community Capitals as Community Resilience to Climate Change: Conceptual Connections

Science.gov (United States)

Kais, Shaikh Mohammad; Islam, Md Saidul

2016-01-01

In the last few decades, disaster risk reduction programs and climate initiatives across the globe have focused largely on the intimate connections between vulnerability, recovery, adaptation, and coping mechanisms. Recent focus, however, is increasingly paid to community resilience. Community, placed at the intersection between the household and national levels of social organization, is crucial in addressing economic, social, or environmental disturbances disrupting human security. Resilience measures a community’s capability of bouncing back—restoring the original pre-disaster state, as well as bouncing forward—the capacity to cope with emerging post-disaster situations and changes. Both the ‘bouncing back’ and ‘moving forward’ properties of a community are shaped and reshaped by internal and external shocks such as climate threats, the community’s resilience dimensions, and the intensity of economic, social, and other community capitals. This article reviews (1) the concept of resilience in relation to climate change and vulnerability; and (2) emerging perspectives on community-level impacts of climate change, resilience dimensions, and community capitals. It argues that overall resilience of a place-based community is located at the intersection of the community’s resilience dimensions, community capitals, and the level of climate disruptions. PMID:27929448

Community expectations

International Nuclear Information System (INIS)

Kraemer, L.

2004-01-01

Historically, the relationship between the nuclear generator and the local community has been one of stability and co-operation. However in more recent times (2000-2003) the nuclear landscape has had several major issues that directly effect the local nuclear host communities. - The associations mandate is to be supportive of the nuclear industry through ongoing dialogue, mutual cooperation and education, - To strengthen community representation with the nuclear industry and politically through networking with other nuclear host communities. As a result of these issues, the Mayors of a number of communities started having informal meetings to discuss the issues at hand and how they effect their constituents. These meetings led to the official formation of the CANHC with representation from: In Canada it is almost impossible to discuss decommissioning and dismantling of Nuclear Facilities without also discussing Nuclear Waste disposal for reasons that I will soon make clear. Also I would like to briefly touch on how and why expectation of communities may differ by geography and circumstance. (author)

Multifractal spatial patterns and diversity in an ecological succession.

Directory of Open Access Journals (Sweden)

Leonardo Ariel Saravia

Full Text Available We analyzed the relationship between biodiversity and spatial biomass heterogeneity along an ecological succession developed in the laboratory. Periphyton (attached microalgae biomass spatial patterns at several successional stages were obtained using digital image analysis and at the same time we estimated the species composition and abundance. We show that the spatial pattern was self-similar and as the community developed in an homogeneous environment the pattern is self-organized. To characterize it we estimated the multifractal spectrum of generalized dimensions D(q. Using D(q we analyze the existence of cycles of heterogeneity during succession and the use of the information dimension D(1 as an index of successional stage. We did not find cycles but the values of D(1 showed an increasing trend as the succession developed and the biomass was higher. D(1 was also negatively correlated with Shannon's diversity. Several studies have found this relationship in different ecosystems but here we prove that the community self-organizes and generates its own spatial heterogeneity influencing diversity. If this is confirmed with more experimental and theoretical evidence D(1 could be used as an index, easily calculated from remote sensing data, to detect high or low diversity areas.

The community comes to campus: the Patient and Community Fair.

Science.gov (United States)

Towle, Angela; Godolphin, William; Kline, Cathy

2015-08-01

Community-based learning connects students with local communities so that they learn about the broad context in which health and social care is provided; however, students usually interact with only one or a few organisations that serve a particular population. One example of a community-based learning activity is the health fair in which students provide health promotion and screening for local communities. We adapted the health fair concept to develop a multi-professional educational event at which, instead of providing service, students learn from and about the expertise and resources of not-for-profit organisations. The fair is an annual 1-day event that students can attend between, or in place of, classes. Each community organisation has a booth to display information. One-hour 'patient panels' are held on a variety of topics throughout the day. Evaluation methods include questionnaires, exit interviews and visitor tracking sheets. Over 5 years (2009-2013), the fair increased in size with respect to estimated attendance, number of participating organisations, number of patient panels and number of students for whom the fair is a required curriculum component. Students learn about a range of patient experiences and community resources, and information about specific diseases or conditions. The fair is an efficient way for students to learn about a range of community organisations. It fosters university-community engagement through continuing connections between students, faculty members and community organisations. Lessons learned include the need for community organisations to have techniques to engage students, and ways to overcome challenges of evaluating an informal 'drop-in' event. The fair is an efficient way for students to learn about a range of community organisations. © 2015 John Wiley & Sons Ltd.

Is a community still a community? Reviewing definitions of key terms in community ecology

OpenAIRE

Stroud, James T.; Bush, Michael R.; Ladd, Mark C.; Nowicki, Robert J.; Shantz, Andrew A.; Sweatman, Jennifer

2015-01-01

Abstract Community ecology is an inherently complicated field, confounded by the conflicting use of fundamental terms. Nearly two decades ago, Fauth et?al. (1996) demonstrated that imprecise language led to the virtual synonymy of important terms and so attempted to clearly define four keywords in community ecology; ?community,? ?assemblage,? ?guild,? and ?ensemble?. We revisit Fauth et?al.'s conclusion and discuss how the use of these terms has changed over time since their review. An update...

Community College Program Planning: A Method to Measure and Meet Community Need

Science.gov (United States)

Perez-Vergara, Kelly; Lathrop, Rachel; Orlowski, Martin

2018-01-01

Offering academic programs that meet community need has long been a core mission of community colleges. However, determining which job skills and credentials are needed for employment in the community is challenging. In order to facilitate a holistic and community-based perspective, our 2-year community college developed a structured curricular…

The community ecology of pathogens: coinfection, coexistence and community composition.

Science.gov (United States)

Seabloom, Eric W; Borer, Elizabeth T; Gross, Kevin; Kendig, Amy E; Lacroix, Christelle; Mitchell, Charles E; Mordecai, Erin A; Power, Alison G

2015-04-01

Disease and community ecology share conceptual and theoretical lineages, and there has been a resurgence of interest in strengthening links between these fields. Building on recent syntheses focused on the effects of host community composition on single pathogen systems, we examine pathogen (microparasite) communities using a stochastic metacommunity model as a starting point to bridge community and disease ecology perspectives. Such models incorporate the effects of core community processes, such as ecological drift, selection and dispersal, but have not been extended to incorporate host-pathogen interactions, such as immunosuppression or synergistic mortality, that are central to disease ecology. We use a two-pathogen susceptible-infected (SI) model to fill these gaps in the metacommunity approach; however, SI models can be intractable for examining species-diverse, spatially structured systems. By placing disease into a framework developed for community ecology, our synthesis highlights areas ripe for progress, including a theoretical framework that incorporates host dynamics, spatial structuring and evolutionary processes, as well as the data needed to test the predictions of such a model. Our synthesis points the way for this framework and demonstrates that a deeper understanding of pathogen community dynamics will emerge from approaches working at the interface of disease and community ecology. © 2015 John Wiley & Sons Ltd/CNRS.

Measurement of Community Empowerment in Three Community Programs in Rapla (Estonia)

Science.gov (United States)

Kasmel, Anu; Andersen, Pernille Tanggaard

2011-01-01

Community empowerment approaches have been proven to be powerful tools for solving local health problems. However, the methods for measuring empowerment in the community remain unclear and open to dispute. This study aims to describe how a context-specific community empowerment measurement tool was developed and changes made to three health promotion programs in Rapla, Estonia. An empowerment expansion model was compiled and applied to three existing programs: Safe Community, Drug/HIV Prevention and Elderly Quality of Life. The consensus workshop method was used to create the measurement tool and collect data on the Organizational Domains of Community Empowerment (ODCE). The study demonstrated considerable increases in the ODCE among the community workgroup, which was initiated by community members and the municipality’s decision-makers. The increase was within the workgroup, which had strong political and financial support on a national level but was not the community’s priority. The program was initiated and implemented by the local community members, and continuous development still occurred, though at a reduced pace. The use of the empowerment expansion model has proven to be an applicable, relevant, simple and inexpensive tool for the evaluation of community empowerment. PMID:21556179

Measurement of Community Empowerment in Three Community Programs in Rapla (Estonia

Directory of Open Access Journals (Sweden)

Pernille Tanggaard Andersen

2011-03-01

Full Text Available Community empowerment approaches have been proven to be powerful tools for solving local health problems. However, the methods for measuring empowerment in the community remain unclear and open to dispute. This study aims to describe how a context-specific community empowerment measurement tool was developed and changes made to three health promotion programs in Rapla, Estonia. An empowerment expansion model was compiled and applied to three existing programs: Safe Community, Drug/HIV Prevention and Elderly Quality of Life. The consensus workshop method was used to create the measurement tool and collect data on the Organizational Domains of Community Empowerment (ODCE. The study demonstrated considerable increases in the ODCE among the community workgroup, which was initiated by community members and the municipality’s decision-makers. The increase was within the workgroup, which had strong political and financial support on a national level but was not the community’s priority. The program was initiated and implemented by the local community members, and continuous development still occurred, though at a reduced pace. The use of the empowerment expansion model has proven to be an applicable, relevant, simple and inexpensive tool for the evaluation of community empowerment.

Community.

Science.gov (United States)

Grauer, Kit, Ed.

1995-01-01

Art in context of community is the theme of this newsletter. The theme is introduced in an editorial "Community-Enlarging the Definition" (Kit Grauer). Related articles include: (1) "The Children's Bridge is not Destroyed: Heart in the Middle of the World" (Emil Robert Tanay); (2) "Making Bridges: The Sock Doll…

Community Bioethics: The Health Decisions Community Council.

Science.gov (United States)

Gallegos, Tom; Mrgudic, Kate

1993-01-01

Sees health care decision making posing variety of complex issues for individuals, families, and providers. Describes Health Decisions Community Council (HDCC), community-based bioethics committee established to offer noninstitutional forum for discussion of health care dilemmas. Notes that social work skills and values for autonomy and…

Community Cookbooks: Sponsors of Literacy and Community Identity

Science.gov (United States)

Mastrangelo, Lisa

2015-01-01

This article looks at the various ways that communities can be "read" through their cookbooks. Recipes and collections can reveal much about communities, including shared memories/traditions, geographical identifications, and representations of class.

Community resiliency as a measure of collective health status: perspectives from rural communities.

Science.gov (United States)

Kulig, Judith C; Edge, Dana; Joyce, Brenda

2008-12-01

Community resiliency is a theoretical framework useful for describing the process used by communities to address adversity. A mixed-method 2-year case study was conducted to gather information about community resiliency in 2 rural communities. This article focuses on the themes generated from qualitative interviews with 55 members of these communities. The participants viewed community as a place of interdependence and interaction. The majority saw community resiliency as the ability to address challenges. Characteristics included physical and social infrastructure, population characteristics, conceptual characteristics, and problem-solving processes. Barriers included negative individual attitudes and lack of infrastructure in rural communities. Nurses could play a key role in enhancing the resiliency of rural communities by developing and implementing programs based on the Community Resiliency Model, which was supported in this study.

Mining with communities

International Nuclear Information System (INIS)

Veiga, Marcello M.; Scoble, Malcolm; McAllister, Mary Louise

2001-01-01

To be considered as sustainable, a mining community needs to adhere to the principles of ecological sustainability, economic vitality and social equity. These principles apply over a long time span, covering both the life of the mine and post-mining closure. The legacy left by a mine to the community after its closure is emerging as a significant aspect of its planning. Progress towards sustainability is made when value is added to a community with respect to these principles by the mining operation during its life cycle. This article presents a series of cases to demonstrate the diverse potential challenges to achieving a sustainable mining community. These case studies of both new and old mining communities are drawn mainly from Canada and from locations abroad where Canadian companies are now building mines. The article concludes by considering various approaches that can foster sustainable mining communities and the role of community consultation and capacity building. (author)

Renewal strategy and community based organisations in community ...

African Journals Online (AJOL)

Renewal strategy and community based organisations in community ... the local population and resources to do that which the governments had failed to do. ... country with a view to reducing poverty and developmental imbalance in Nigeria.

Involving the Community

International Development Research Centre (IDRC) Digital Library (Canada)

Step 3: Identifying the different community groups and other stakeholders concerned .... How can two-way communication enhance community participation in ...... for maintenance and the rights of specific community groups to drinkable water.

Community Ecology

CERN Document Server

1988-01-01

This book presents the proceedings of a workshop on community ecology organized at Davis, in April, 1986, sponsored by the Sloan Foundation. There have been several recent symposia on community ecology (Strong et. al., 1984, Diamond and Case, 1987) which have covered a wide range of topics. The goal of the workshop at Davis was more narrow: to explore the role of scale in developing a theoretical approach to understanding communities. There are a number of aspects of scale that enter into attempts to understand ecological communities. One of the most basic is organizational scale. Should community ecology proceed by building up from population biology? This question and its ramifications are stressed throughout the book and explored in the first chapter by Simon Levin. Notions of scale have long been important in understanding physical systems. Thus, in understanding the interactions of organisms with their physical environment, questions of scale become paramount. These more physical questions illustrate the...

Using communities that care for community child maltreatment prevention.

Science.gov (United States)

Salazar, Amy M; Haggerty, Kevin P; de Haan, Benjamin; Catalano, Richard F; Vann, Terri; Vinson, Jean; Lansing, Michaele

2016-03-01

The prevention of mental, emotional, and behavioral (MEB) disorders among children and adolescents is a national priority. One mode of implementing community-wide MEB prevention efforts is through evidence-based community mobilization approaches such as Communities That Care (CTC). This article provides an overview of the CTC framework and discusses the adaptation process of CTC to prevent development of MEBs through preventing child abuse and neglect and bolstering child well-being in children aged 0 to 10. Adaptations include those to the intervention itself as well as those to the evaluation approach. Preliminary findings from the Keeping Families Together pilot study of this evolving approach suggest that the implementation was manageable for sites, and community board functioning and community adoption of a science-based approach to prevention in pilot sites looks promising. Implications and next steps are outlined. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

Descriptions of Community by People with Spinal Cord Injuries: Concepts to Inform Community Integration and Community Rehabilitation

Science.gov (United States)

Kuipers, Pim; Kendall, Melissa B.; Amsters, Delena; Pershouse, Kiley; Schuurs, Sarita

2011-01-01

Effective measurement and optimization of re-entry into the community after injury depends on a degree of understanding of how those injured persons actually perceive their community. In light of the limited research about foundational concepts regarding community integration after spinal cord injury, this study investigated how a large number of…

Re-imagining occupational therapy clients as communities: Presenting the community-centred practice framework.

Science.gov (United States)

Hyett, Nerida; Kenny, Amanda; Dickson-Swift, Virginia

2018-01-09

Occupational therapists' are increasingly working with communities and providing services at the community level. There is, however, a lack of conceptual frameworks to guide this work. The aim of this article is to present a new conceptual framework for community-centered practice in occupational therapy. The conceptual framework was developed from qualitative multi-case research on exemplars of community participation. The first was, a network of Canadian food security programs, and the second, a rural Australian community banking initiative. Key themes were identified from across the case studies, and cross-case findings interpreted using occupational therapy and occupational science knowledge, and relevant social theory. The outcome is a four-stage, occupation-focused, community-centered practice framework. The Community-Centred Practice Framework can be used by occupational therapists to understand and apply a community-centered practice approach. The four stages are: (1) Community Identity, (2) Community Occupations, (3) Community Resources and Barriers, and (4) Participation Enablement. Further research is needed to trial and critically evaluate the framework, to assess its usefulness as a robust, occupation-focused, frame of reference to guide community-centered practice in occupational therapy. The proposed framework should assist occupational therapists to conceptualize community-centered practice, and to utilize and apply theory.

Community assembly and coexistence in communities of arbuscular mycorrhizal fungi.

Science.gov (United States)

Vályi, Kriszta; Mardhiah, Ulfah; Rillig, Matthias C; Hempel, Stefan

2016-10-01

Arbuscular mycorrhizal fungi are asexual, obligately symbiotic fungi with unique morphology and genomic structure, which occupy a dual niche, that is, the soil and the host root. Consequently, the direct adoption of models for community assembly developed for other organism groups is not evident. In this paper we adapted modern coexistence and assembly theory to arbuscular mycorrhizal fungi. We review research on the elements of community assembly and coexistence of arbuscular mycorrhizal fungi, highlighting recent studies using molecular methods. By addressing several points from the individual to the community level where the application of modern community ecology terms runs into problems when arbuscular mycorrhizal fungi are concerned, we aim to account for these special circumstances from a mycocentric point of view. We suggest that hierarchical spatial structure of arbuscular mycorrhizal fungal communities should be explicitly taken into account in future studies. The conceptual framework we develop here for arbuscular mycorrhizal fungi is also adaptable for other host-associated microbial communities.

Community impact management

International Nuclear Information System (INIS)

Baril, R.G.

1983-01-01

Industrial expansion, whether for resource extraction, refining, production or distribution and particularly the construction of energy facilities, usually has many effects on communities. In the early 1970s, as more experience was gained with large projects and as communities became more sensitive to their needs and rights, the negative effects of projects gained some prominence. Communities questioned whether it was in their best interest to accept changes that large corporations would impose on them. It is in this context that Ontario Hydro, in 1977, set up the first of four community impact agreements for the construction of generating stations. This paper discusses these community impact agreements and how they have become the framework for the management of community impacts. Also, the paper discusses a model for compensating social impacts

Invasion in microbial communities: Role of community composition and assembly processes

DEFF Research Database (Denmark)

Kinnunen, Marta

of microbial community assembly. Biotic factors include interactions between different microbial groups as well as the community response to alien species – invaders. Microbial invasions can have significant effects on the composition and functioning of resident communities. There is, however, lack......Microbes contribute to all biogeochemical cycles on earth and are responsible for key biological processes that support the survival of plants and animals. There is increased interest in controlling and managing microbial communities in different ecosystems in order to make targeted microbiological...... processes more effective. In order to manage microbial communities, it is essential to understand the factors that shape and influence microbial community composition. In addition to abiotic factors, such as environmental conditions and resource availability, biotic factors also shape the dynamics...

Estimation of different source contributions to sediment organic matter in an agricultural-forested watershed using end member mixing analyses based on stable isotope ratios and fluorescence spectroscopy.

Science.gov (United States)

Derrien, Morgane; Kim, Min-Seob; Ock, Giyoung; Hong, Seongjin; Cho, Jinwoo; Shin, Kyung-Hoon; Hur, Jin

2018-03-15

The two popular source tracing tools of stable isotope ratios (δ 13 C and δ 15 N) and fluorescence spectroscopy were used to estimate the relative source contributions to sediment organic matter (SeOM) at five different river sites in an agricultural-forested watershed (Soyang Lake watershed), and their capabilities for the source assignment were compared. Bulk sediments were used for the stable isotopes, while alkaline extractable organic matter (AEOM) from sediments was used to obtain fluorescent indices for SeOM. Several source discrimination indices were fully compiled for a range of the SeOM sources distributed in the catchments of the watershed, which included soils, forest leaves, crop (C3 and C4) and riparian plants, periphyton, and organic fertilizers. The relative source contributions to the river sediment samples were estimated via end member mixing analysis (EMMA) based on several selected discrimination indices. The EMMA based on the isotopes demonstrated that all sediments were characterized by a medium to a high contribution of periphyton ranging from ~30% to 70% except for one site heavily affected by forest and agricultural fields with relatively high contributions of terrestrial materials. The EMMA based on fluorescence parameters, however, did not show similar results with low contributions from forest leaf and periphyton. The characteristics of the studied watershed were more consistent with the source contributions determined by the isotope ratios. The discrepancy in the EMMA capability for source assignments between the two analytical tools can be explained by the limited analytical window of fluorescence spectroscopy for non-fluorescent dissolved organic matter (FDOM) and the inability of AEOM to represent original bulk particulate organic matter (POM). Copyright © 2017 Elsevier B.V. All rights reserved.

Gamma emitting radionuclides of the Test Reactor Area leaching ponds

International Nuclear Information System (INIS)

Millard, J.B.; Whicker, F.W.; Markham, O.D.

1978-01-01

Radioactive leaching ponds adjacent to the Test Reactor Area (TRA) located on the Idaho National Engineering Laboratory (INEL) Site were investigated to determine the seasonal distribution and ecological behavior of gamma emitting radionuclides. The potential hazards to man and the environment were considered through the biological export of radioactive materials from the ponds. Both biotic and abiotic pond compartments were sampled. Fall and winter biomass estimates showed that benthic periphyton comprised 52%, macrophytes and littoral vegetation 35%, and seston 10% of the total for all biotic compartments. Concentrations and concentration factors (CFs) for fall and winter are presented for Cr-51, Co-60, Zr-95, I-131, Cs-137, Ba-140, and Ce-141. Concentrations and CFs ranged over seven orders of magnitude for the various nuclides and compartments. Seston and zooplankton had the highest concentrations followed by periphyton, sediment, macrophytes, littoral plants, willow, and filtered water. Arthropods had variable concentrations and CFs. Significant seasonal differences were observed for concentrations and CFs in seston, macrophytes, and littoral vegetation. A compartmental inventory of total gamma emitting activity accounted for 254 Ci (9.25 TBq) of the 731 Ci (24.8 TBq) estimated to remain in the ponds at the time of sampling. Filtered water and surface sediments contained 99% of the total radioactivity, while periphyton and seston had most of the remaining 1%. An estimate of the avian export rate of radioactivity from the TRA ponds showed that potentially harvestable mourning doves had the lowest rate with 0.02 μCi/y. External tissues of migratory waterfowl were found to contribute 90% of the total exported activity for all birds. The total avian export rate was estimated to be 1350 μCi/y during 1975

Commentary on the Future of Community Psychology: Perspective of a Research Community Psychologist.

Science.gov (United States)

Milburn, Norweeta G

2016-12-01

Community psychology is commented upon from the perspective of a community psychologist who was trained in the Community Psychology Program at the University of Michigan in Ann Arbor. Her background and training are reviewed. A brief survey of research on homelessness as a frame for community psychology research is presented. Concluding remarks are provided on the future of research in community psychology. © Society for Community Research and Action 2016.

Interrupting Mythic Community

Directory of Open Access Journals (Sweden)

Linnell Secomb

2013-09-01

Full Text Available If nation is increasingly perceived as a less than honourable institution formed through war, invasion and geo-political territorialisation, and government is widely denounced as the site of political intrigue and the means of subjectification of citizen–voters, community appears to escape this critique and to be viewed as an idyllic formation based on bonds of affinity. However, this romancing of community is disrupted by trans-cultural and sub-cultural formations that expose the fantasy of a harmonious, homogenous community. While community is often conceived as arising organically from familial, tribal or cultural similarity, or as constituted through a common history and shared cultural institutions, this totalising conception of community is interrupted by the demands of difference and heterogeneity and by a questioning of the idyll of community authenticated in myths of archaic origin.

Occurrence and distribution of monomethylalkanes in the freshwater wetland ecosystem of the Florida Everglades.

Science.gov (United States)

He, Ding; Simoneit, Bernd R T; Jara, Blanca; Jaffé, Rudolf

2015-01-01

A series of mono-methylalkanes (MMAs) with carbon numbers from C10 to C23 and C29 were detected in freshwater wetlands of the Everglades. A decrease in concentration and molecular complexity was observed in the order from periphyton and floc, to surface soil and deeper soil horizons. These compounds were present in varying amounts up to 27 μg gdw(-1) in periphyton, 74 μg gdw(-1) in floc, 1.8 μg gdw(-1) in surface soil, <0.03 μg gdw(-1) in deeper soils (12-15 cm). A total of 46 MMAs, including three iso and three anteiso-alkanes, were identified. Compound specific carbon isotopes values were determined for some dominant MMAs, and suggest that they originate from microbial sources, including cyanobacteria. Potential decarboxylation from fatty acids could also potentially contribute to the MMAs detected. Early diagenetic degradation was suggested to affect the accumulation of MMAs in soils and further studies are needed to address their applications as biomarkers. Copyright © 2014 Elsevier Ltd. All rights reserved.

Invasion of an occupied niche by the crayfish Orconectes rusticus: potential importance of growth and mortality.

Science.gov (United States)

Hill, Anna M; Sinars, Damon M; Lodge, David M

1993-06-01

We are exploring mechanisms of an invasion that contradicts the oft-cited generalization that species invade vacant niches. In northern Wisconsin lakes, the introduced crayfish Orconectes rusticus is replacing two ecologically similar resident congeners, O. virilis and O. propinquus. In laboratory experiments, we compared growth and mortality of individually maintained crayfish offered one of five ad libitum diets: invertebrates, macrophytes, dentritus, periphyton or all items combined. Mortality was highest for O. virilis and lowest for O. rusticus. Macrophyte diets yielded the highest mortality. All three species grew best on invertebrate and combination diets but grew little or not at all on diets of periphyton, detritus or macrophytes. O. rusticus and O. virilis grew more than O. propinquus. O. rusticus grew more quickly and/or was better able to survive overall than its congeners. Therefore, O. rusticus would probably have advantages over O. virilis and O. propinquus in competitive interactions, reproductive success and avoiding size-selective fish predation. Subtle interspecific differences may interact strongly with other ecological factors and contribute to the displacement of resident species from a well-occupied niche.

Seasonal distribution and uptake of gamma emitting radionuclides at the test reactor area leaching ponds

International Nuclear Information System (INIS)

Millard, J.B.

1986-01-01

Radioactive leaching ponds adjacent to the Test Reactor Area (TRA) located on the Idaho National Engineering Laboratory (INEL) site were investigated to determine the seasonal distribution and ecological behavior of gamma emitting radionuclides in various pond compartments. The physical, chemical and biological properties of the TRA ponds were documented including basic morphometry, water chemistry and species identification. Penetrating radiation exposure rates at the ponds ranged from 35 to 65 mR/d at the water surface and up to 3400 mR/d one meter above bottom sediments. Seasonal concentrations and concentration ratios were determined for 16 principle radionuclides in filtered water, sediment, seston, zooplankton, net plankton, nannoplankton, periphyton, macrophytes, thistle, speedwell and willow. Seston and nannoplankton had the highest concentration ratios with substantial decreases observed for higher trophic level compartments. Significant (P < 0.01 to P < 0.001) seasonal effects wee found for concentration ratios. Radionuclides without nutrient analogs had the highest ratios in spring for periphyton, macrophytes and littoral plants. Concentration ratios were highest in summer, fall or winter for radionuclides with nutrient analogs

Sense of community: perceptions of individual and group members of online communities

NARCIS (Netherlands)

Kommers, Petrus A.M.; Bishop, Jonathan

2014-01-01

This chapter addresses the relation community-society in the case of Web-based constellations; how is society represented if we meet Web-based communities? Why are Web-based societies kept invisible while Web-communities emerge as a quasi-natural consequence of Web presence? Did Web-communities

Measuring disaster-resilient communities: a case study of coastal communities in Indonesia.

Science.gov (United States)

Kafle, Shesh Kanta

2012-01-01

Vulnerability reduction and resilience building of communities are central concepts in recent policy debates. Although there are fundamental linkages, and complementarities exist between the two concepts, recent policy and programming has focused more on the latter. It is assumed here that reducing underlying causes of vulnerabilities and their interactions with resilience elements is a prerequisite for obtaining resilience capabilities. An integrated approach, incorporating both the vulnerability and resilience considerations, has been taken while developing an index for measuring disaster-resilient communities. This study outlines a method for measuring community resilience capabilities using process and outcome indicators in 43 coastal communities in Indonesia. An index was developed using ten process and 25 outcome indicators, selected on the basis of the ten steps of the Integrated Community Based Risk Reduction (ICBRR) process, and key characteristics of disaster resilient communities were taken from various literatures. The overall index value of all 43 communities was 63, whereas the process and outcome indicator values were measured as 63 and 61.5 respectively. The core components of this index are process and outcome indicators. The tool has been developed with an assumption that both the process and outcome indicators are equally important in building disaster-resilient communities. The combination of both indicators is an impetus to quality change in the community. Process indicators are important for community understanding, ownership and the sustainability of the programme; whereas outcome indicators are important for the real achievements in terms of community empowerment and capacity development. The process of ICBRR approach varies by country and location as per the level of community awareness and organisational strategy. However, core elements such as the formation of community groups, mobilising those groups in risk assessment and planning

Social science constructs in ecosystem assessments: revisiting community capacity and community resiliency.

Science.gov (United States)

Ellen M. Donoghue; Victoria E. Sturtevant

2007-01-01

This article explores the development of sociological constructs in community assessment components of large-scale ecosystem assessments. We compare the conceptual and operational development of the constructs of community capacity and community resiliency used in three community assessments in the western United States: the Forest Ecosystem Management Assessment Team...

Community Garden Information Systems: Analyzing and Strengthening Community-Based Resource Sharing Networks

Science.gov (United States)

Loria, Kristen

2013-01-01

Extension professionals play an increasingly central role in supporting community garden and other community-based agriculture projects. With growing interest in community gardens as tools to improve community health and vitality, the best strategies for supporting these projects should be explored. Due to the importance of inter-personal networks…

Community concepts.

Science.gov (United States)

Yeung, Thomas; Bates, Tony

2004-03-01

Since the publication of "Sustainable Communities--building for the future", Government attention has focused largely on high-density affordable housing in the four "growth areas": Thames Gateway; Ashford; Milton Keynes--South Midlands, and London--Stansted--Cambridge. In this article, Thomas Yeung and Tony Bates suggest that a greater and more sustainable impact would be achieved if architects, planners, and developers considered the potential for community-based water and waste management and on-site energy generation and distribution right from the start of the project. In particular, they consider that the communal nature of hospitals, universities, and public/community housing provides a great opportunity for on-site renewable CHP and/or distributed heating, which could combine global environmental benefits with improved local amenities. They describe a simple model for prioritising energy management in the built environment, and draw on lessons learnt at ETRCL in Dagenham and BedZED in Surrey to offer a few recommendations for Government and developers. Tony Bates is the business development manager for Scott Wilson in the South East and is responsible for the promotion of sustainable communities through relationships with architects, developers, land owners and local authorities. Thomas Yeung leads the Energy Infrastructure Technologies group in Scott Wilson. This team offers an integrated approach to clean community-based energy generation, energy management, waste and water management, sustainable transport, and sustainable buildings/communities.

Loyalty in Online Communities.

Science.gov (United States)

Hamilton, William L; Zhang, Justine; Danescu-Niculescu-Mizil, Cristian; Jurafsky, Dan; Leskovec, Jure

2017-05-01

Loyalty is an essential component of multi-community engagement. When users have the choice to engage with a variety of different communities, they often become loyal to just one, focusing on that community at the expense of others. However, it is unclear how loyalty is manifested in user behavior, or whether certain community characteristics encourage loyalty. In this paper we operationalize loyalty as a user-community relation: users loyal to a community consistently prefer it over all others; loyal communities retain their loyal users over time. By exploring a large set of Reddit communities, we reveal that loyalty is manifested in remarkably consistent behaviors. Loyal users employ language that signals collective identity and engage with more esoteric, less popular content, indicating that they may play a curational role in surfacing new material. Loyal communities have denser user-user interaction networks and lower rates of triadic closure, suggesting that community-level loyalty is associated with more cohesive interactions and less fragmentation into subgroups. We exploit these general patterns to predict future rates of loyalty. Our results show that a user's propensity to become loyal is apparent from their initial interactions with a community, suggesting that some users are intrinsically loyal from the very beginning.

The Social Workers Challenges on Community Welfare in Ungogo Community, Nigeria

Directory of Open Access Journals (Sweden)

Kehinde Adekunle Aliyu

2017-10-01

Full Text Available The role of social workers in a community cannot be overemphasised by any mean, for the life span of any community depends on the quality of the social workers. The aim of this work is to affirm the roles of social workers in helping the community welfare.  Qualitative research design was adopted for the work. Data collected with the Interview Schedule for Officials of the Federal Road Safety Corps and Interview Guide for selected group of people. This was administered to 30 respondents, which comprises both male and female in the Ungogo community. The purpose of the study was to examine the roles of social workers, in line with improved standards of living, sustained economic development and expansion of trade and economic relations in the community; enhanced levels of international competitiveness in the areas of community welfare, organization for increased productivity of people in the community. It common knowledge every individual strife to be the best when receive the necessary or adequate encouragement. To these extents, such a person bears some responsibilities even if passively so as a member. The implication of this work is to contribute to social change by informing social worker on their challenges and responsibilities ahead of them in the community.

Discourse Communities and Communities of Practice

DEFF Research Database (Denmark)

Pogner, Karl-Heinz

2005-01-01

This paper aims at giving a more detailed description and discussion of two concepts of `community' developed in the research areas of text production/ writing and social learning / information management / knowledge sharing and comparing them with each other. The purpose of this theoretical exer...... production at different Danish workplaces (a consulting engi-neering company, a university department and a bank) and discusses their significance in the context of co-located as well as geographically distrib-uted communities....

An Open Letter to the Cancer Community Regarding Community Clinical Trials

Science.gov (United States)

The National Cancer Institute (NCI) is in the process of combining its two community-based research networks to create a single network that builds on the strengths of the Community Clinical Oncology Program/Minority-Based Community Clinical Oncology Prog

Corporate Philanthropy Toward Community Health Improvement in Manufacturing Communities.

Science.gov (United States)

McHugh, Megan; Farley, Diane; Maechling, Claude R; Dunlop, Dorothy D; French, Dustin D; Holl, Jane L

2018-06-01

Virtually all large employers engage in corporate philanthropy, but little is known about the extent to which it is directed toward improving community health. We conducted in-depth interviews with leaders of corporate philanthropy from 13 of the largest manufacturing companies in the US to understand how giving decisions were made, the extent to which funding was directed towards improving community health, and whether companies coordinate with local public health agencies. We found that corporate giving was sizable and directed towards communities in which the manufacturers have a large presence. Giving was aligned with the social determinants of health (i.e., aimed at improving economic stability, the neighborhood and physical environment, education, food security and nutrition, the community and social context, and the health care system). However, improving public health was not often cited as a goal of corporate giving, and coordination with public health agencies was limited. Our results suggest that there may be opportunities for public health agencies to help guide corporate philanthropy, particularly by sharing community-level data and offering their measurement and evaluation expertise.

Community Involvement - Outreach / Development

OpenAIRE

2004-01-01

Tonya Aiken: Horse Program Success. Kyle Cecil: Natural Resources and the Extension Educator. Karol Dyson: Building Strong Communities through Empowerment. Lisa Dennis: "Food Smart". Theresa M. Ferrari: Community Service Experiences & 4-H Teens. t. Stacey Harper: Connecting the Youth with the Community. Joseph G. Hiller: Extension Work in Indian Country. Alice P. Kersey: Outreach to the NR Community. Carla M. Sousa: Learning from Latino Community Efforts.

Informing and involving: the community`s right to know [marine oil spills

Energy Technology Data Exchange (ETDEWEB)

Watson, G. [Marine and Coastal Community Network, Perth, WA (Australia)

1996-12-31

The Marine and Coastal Community Network was established in 1993 to facilitate communication between all user groups of Australia`s coasts and seas, to promote ecological sustainability, to encourage greater community involvement, and to provide information. It is proving successful in providing a line of communication between a broad range of sectorial interests and developing a cooperative approach to ecological sustainability. This paper addresses the question of how the oil industry is shaping up in relation to providing relevant, accessible, understandable and up-to-date information to the community, in involving the community, and in developing and delivering industry best practice. It also outlines what the community wants to know and what industry can do better. The community, it is concluded, is always going to react very strongly over oil spills. Maintenance of water quality and the conservation of Australia`s coastline are extremely important issues for the community. A greater willingness to involve the community and a greater commitment to better research and practices is considered necessary. (author). 1 tab., 1 fig., 20 refs.

Renewal Strategy and Community Based Organisations in Community

African Journals Online (AJOL)

FBL

organisations in the study areas and Community-Based Poverty Reduction. Programme ... regions or areas. In Nigeria, for ... industries in the growing and developing urban areas. ..... Security network is also provided by the community. To ..... Development Efforts in Nigeria: Case Study of Anambra and Oyo State, NISER.

Designing for Communities

CERN Multimedia

CERN. Geneva

2011-01-01

In 2008, Mark Boulton's small design firm won the project to redesign drupal.org home to the Drupal open source content management project and its community of over 400,000 users and developers. Designing for open source communities has its challenges: it is a developer-centric environment where discussion, debate and consensus rules and where design processes are often viewed sceptically. To help dispel some misconceptions behind the design process, Mark's team worked completely openly with the Drupal community - and broader the web design community - throughout the project. This talk will walk through some of the challenges and solutions for designing for large communities. Mark will share the successes - and the horror stories - of how a traditional design process was challenged every step of the way and how the Drupal community became an integral part of that new process. Mark and his team will be working with the Communication Group on an open project to r...

Valuing Our Communities: Ethical Considerations for Economic Evaluation of Community-Based Prevention.

Science.gov (United States)

Crowley, Max; Jones, Damon

2017-12-01

Restricted public budgets and increasing efforts to link the impact of community interventions to public savings have increased the use of economic evaluation. While this type of evaluation can be important for program planning, it also raises important ethical issues about how we value the time of local stakeholders who support community interventions. In particular, researchers navigate issues of scientific accuracy, institutional inequality, and research utility in their pursuit of even basic cost estimates. We provide an example of how we confronted these issues when estimating the costs of a large-scale community-based intervention. Principles for valuing community members' time and conducting economic evaluations of community programs are discussed. © Society for Community Research and Action 2017.

Engineering Hybrid Learning Communities: The Case of a Regional Parent Community

Directory of Open Access Journals (Sweden)

Sven Strickroth

2014-09-01

Full Text Available We present an approach (and a corresponding system design for supporting regionally bound hybrid learning communities (i.e., communities which combine traditional face-to-face elements with web based media such as online community platforms, e-mail and SMS newsletters. The goal of the example community used to illustrate the approach was to support and motivate (especially hard-to-reach underprivileged parents in the education of their young children. The article describes the design process used and the challenges faced during the socio-technical system design. An analysis of the community over more than one year indicates that the hybrid approach works better than the two separated “traditional” approaches separately. Synergy effects like advertising effects from the offline trainings for the online platform and vice versa occurred and regular newsletters turned out to have a noticeable effect on the community.

Development of community plans to enhance survivorship from colorectal cancer: community-based participatory research in rural communities.

Science.gov (United States)

Lengerich, Eugene J; Kluhsman, Brenda C; Bencivenga, Marcyann; Allen, Regina; Miele, Mary Beth; Farace, Elana

2007-09-01

In 2002, 10.4% of the 10 million persons alive who have ever been diagnosed with cancer had colorectal cancer (CRC). Barriers, such as distance, terrain, access to care and cultural differences, to CRC survivorship may be especially relevant in rural communities. We tested the hypothesis that teams from rural cancer coalitions and hospitals would develop a Community Plan (CP) to enhance CRC survivorship. We used community-based participatory research and the PRECEDE-PROCEED model to train teams from rural cancer coalitions and hospitals in Pennsylvania and New York. We measured knowledge at three points in time and tested the change with McNemar's test, corrected for multiple comparisons (p < 0.0167). We also conducted a qualitative review of the CP contents. Fourteen (93.3%) of the 15 coalitions or hospitals initially recruited to the study completed a CP. Knowledge in public health, sponsorship of A National Action Plan for Cancer Survivorship, and CRC survivorship and treatment increased. Teams identified perceived barriers and community assets. All teams planned to increase awareness of community assets and almost all planned to enhance treatment-related care and psychosocial care for the CRC survivor; 50% planned to enhance primary care and CRC screening. The study demonstrated the interest and ability of rural organizations to plan to enhance CRC survivorship, including linkage of CRC survivorship to primary care. Rural cancer coalitions and hospitals may be a vehicle to develop local action for A National Action Plan. Access to more comprehensive care for CRC cancer survivors in rural communities appears to be facilitated by the community-based initiative described and investigated in this study. Efforts such as these could be replicated in other rural communities and may impact the care and quality of life of survivors with many types of cancers. While access to health services may be increased through community-based initiatives, we still need to measure

Community Satisfaction in Czech Rural Communities: A Multilevel Model

Czech Academy of Sciences Publication Activity Database

Bernard, Josef

2015-01-01

Roč. 55, č. 2 (2015), s. 205-226 ISSN 0038-0199 Institutional support: RVO:68378025 Keywords : community satisfaction * rural communities * contextual effects Subject RIV: AO - Sociology , Demography Impact factor: 1.380, year: 2015

Training community health students to develop community-requested social marketing campaigns: an innovative partnership.

Science.gov (United States)

Lindsey, Billie J; Hawk, Carol Wetherill

2013-01-01

This paper describes a sustained partnership between a university community health program and local and regional community health agencies. As a key component of the Health Communication and Social Marketing course, the partnership involves undergraduate community health students working for and with community agencies and community members to design social marketing campaigns based on community-identified health needs. The goals of the course are to (1) provide students with the opportunity to work within the community to apply their skills in program planning, evaluation, and communication and (2) provide community agencies with a tailored campaign that can be implemented in their communities. Throughout the 10-week quarter, teams of students follow the principles of community participation in planning a social marketing campaign. These include (1) audience segmentation and formative assessment with the intended audience to determine campaign content and strategies and (2) pretesting and revisions of campaign messages and materials based on community feedback. This partnership contributes to the promotion of health in the local community and it builds the skills and competencies of future health educators. It demonstrates a successful and sustainable combination of community-based participatory research and experiential learning. From 2005 to 2011, 35 campaigns have been developed, many which have been implemented.

Strengthening community leadership: evaluation findings from the california healthy cities and communities program.

Science.gov (United States)

Kegler, Michelle C; Norton, Barbara L; Aronson, Robert E

2008-04-01

Collaborative approaches to community health improvement such as healthy cities and communities have the potential to strengthen community capacity through leadership development. The healthy cities and communities process orients existing local leadership to new community problem-solving strategies and draws out leadership abilities among residents not previously engaged in civic life. In an evaluation of the California Healthy Cities and Communities (CHCC) Program, leadership development was one of several outcomes assessed at the civic-participation level of the social ecology. Data collection methods included focus groups and surveys, semistructured interviews with coordinators and community leaders, and review of program documents. Findings suggest that the CHCC program enhanced capacity by expanding new leadership opportunities through coalition participation, program implementation, and civic leadership roles related to spin-off organizations and broader collaborative structures. Communities in rural regions were particularly successful in achieving significant leadership outcomes.

Food Barn for The Village Community To Strengthen Community Empowerment Program

Directory of Open Access Journals (Sweden)

Maulidyah Indira Hasmarini

2016-12-01

Full Text Available This study aimed to assess the achievement level of community empowerment in realizing food security. The result was expected to reveal a model of community empowerment, particularly farmer community institution as an attempt to attain food security. Survey was employed as the research method that involved the farmers (farmer groups as the members of Food Barn for the Village Community (Lumbung Pangan Masyarakat Desa/LPMD. Technique of rapid rural appraisal was selected in the form of quantitative and qualitative analysis. Preliminary survey in study area was carried out to obtain the characteristic and status of food security; and to mapping the potential and role of Lumbung Pangan Masyarakat Desa in the process of community empowerment. Subsequently, study and analysis was done based on the survey. The results demonstrated the active role of stakeholders (A-B-G-C was significant in supporting the farmer institution (food barn. The economic and social aspects were also evidenced to have important role in enhancing the farmer community empowerment. This model is called social engine for rural community and local institution, particularly to attain the regional food security.

Community organizing and community health: piloting an innovative approach to community engagement applied to an early intervention project in south London.

Science.gov (United States)

Bolton, Matthew; Moore, Imogen; Ferreira, Ana; Day, Crispin; Bolton, Derek

2016-03-01

The importance of community engagement in health is widely recognized, and key themes in UK National Institute for Health and Clinical Excellence (NICE) recommendations for enhancing community engagement are co-production and community control. This study reports an innovative approach to community engagement using the community-organizing methodology, applied in an intervention of social support to increase social capital, reduce stress and improve well-being in mothers who were pregnant and/or with infants aged 0-2 years. Professional community organizers in Citizens-UK worked with local member civic institutions in south London to facilitate social support to a group of 15 new mothers. Acceptability of the programme, adherence to principles of co-production and community control, and changes in the outcomes of interest were assessed quantitatively in a quasi-experimental design. The programme was found to be feasible and acceptable to participating mothers, and perceived by them to involve co-production and community control. There were no detected changes in subjective well-being, but there were important reductions in distress on a standard self-report measure (GHQ-12). There were increases in social capital of a circumscribed kind associated with the project. Community organizing provides a promising model and method of facilitating community engagement in health. © The Author 2015. Published by Oxford University Press on behalf of Faculty of Public Health.

The Communities Advancing Resilience Toolkit (CART): an intervention to build community resilience to disasters.

Science.gov (United States)

Pfefferbaum, Rose L; Pfefferbaum, Betty; Van Horn, Richard L; Klomp, Richard W; Norris, Fran H; Reissman, Dori B

2013-01-01

Community resilience has emerged as a construct to support and foster healthy individual, family, and community adaptation to mass casualty incidents. The Communities Advancing Resilience Toolkit (CART) is a publicly available theory-based and evidence-informed community intervention designed to enhance community resilience by bringing stakeholders together to address community issues in a process that includes assessment, feedback, planning, and action. Tools include a field-tested community resilience survey and other assessment and analytical instruments. The CART process encourages public engagement in problem solving and the development and use of local assets to address community needs. CART recognizes 4 interrelated domains that contribute to community resilience: connection and caring, resources, transformative potential, and disaster management. The primary value of CART is its contribution to community participation, communication, self-awareness, cooperation, and critical reflection and its ability to stimulate analysis, collaboration, skill building, resource sharing, and purposeful action.

The Learning Community.

Science.gov (United States)

Boo, Mary Richardson; Decker, Larry E.

This guide to community education offers strategies and suggestions for responding to the call for more community involvement in partnership efforts that will benefit education and society. First, a brief introduction summarizes the philosophy of community education, defining it as a belief that learning is lifelong and that self-help efforts…

Community energy auditing: experience with the comprehensive community energy management program

Energy Technology Data Exchange (ETDEWEB)

Moore, J.L.; Berger, D.A.; Rubin, C.B.; Hutchinson, P.A. Sr.; Griggs, H.M.

1980-09-01

The report provides local officials and staff with information on lessons from the audit, projection, and general planning experiences of the Comprehensive Community Energy Management Program (CCEMP) communities and provides ANL and US DOE with information useful to the further development of local energy management planning methods. In keeping with the objectives, the report is organized into the following sections: Section II presents the evaluation issues and key findings based on the communities' experiences from Spring of 1979 to approximately March of 1980; Section III gives an organized review of experience of communities in applying the detailed audit methodology for estimating current community energy consumption and projecting future consumption and supply; Section IV provides a preliminary assessment of how audit information is being used in other CCEMP tasks; Section V presents an organized review of preliminary lessons from development of the community planning processes; and Section VI provides preliminary conclusions on the audit and planning methodology. (MCW)

Defining political community

Directory of Open Access Journals (Sweden)

Sladeček Michal M.

2002-01-01

Full Text Available This paper considers the concept of political community, its constitution and value. The starting point is that the concept of community is not sufficiently recognized in modern political theories, as well as in contemporary liberal theory. In the last two decades communitarian and republican political theory attempted to revitalize this notion. The first part of the paper elaborates on the polemics between these three theoretical orientations. The concluding part examines the possibilities and prospect for stable political community in conditions of pluralism of particular social communities and ethnocultural heterogeneity.

A la Carte Community

DEFF Research Database (Denmark)

Gundelach, Peter; Brincker, Benedikte

2010-01-01

and shows that there are high levels of virtual as well as face-to-face interaction among the members. The participants feel that they belong to the community and many also feel that they are recognised as part of the community. However, the members do not share common values neither in relation to software......The exchange of open source software is a phenomenon that is becoming in- creasingly significant to IT users. This article presents the results of a study of the TYPO3 community, a community related to an open source CMS software. The article explores the community, identity and values of TYPO3...... pro- duction nor generally. Instead, they stress that you are free to choose your own values. Against this background, the authors introduce the notion of an ‘a la carte community', i.e. a community where individuals pick and choose their degree of participation and integra- tion into the community...

Community noise

Science.gov (United States)

Bragdon, C. R.

Airport and community land use planning as they relate to airport noise reduction are discussed. Legislation, community relations, and the physiological effect of airport noise are considered. Noise at the Logan, Los Angeles, and Minneapolis/St. Paul airports is discussed.

Celebrating indigenous communities compassionate traditions.

Science.gov (United States)

Prince, Holly

2018-01-01

Living in a compassionate community is not a new practice in First Nations communities; they have always recognized dying as a social experience. First Nations hold extensive traditional knowledge and have community-based practices to support the personal, familial, and community experiences surrounding end-of-life. However, western health systems were imposed and typically did not support these social and cultural practices at end of life. In fact, the different expectations of western medicine and the community related to end of life care has created stress and misunderstanding for both. One solution is for First Nations communities to develop palliative care programs so that people can receive care at home amongst their family, community and culture. Our research project "Improving End-of-Life Care in First Nations Communities" (EOLFN) was funded by the Canadian Institutes of Health Research [2010-2015] and was conducted in partnership with four First Nations communities in Canada (see www.eolfn.lakeheadu.ca). Results included a community capacity development approach to support Indigenous models of care at end-of-life. The workshop will describe the community capacity development process used to develop palliative care programs in First Nations communities. It will highlight the foundation to this approach, namely, grounding the program in community values and principles, rooted in individual, family, community and culture. Two First Nations communities will share stories about their experiences developing their own palliative care programs, which celebrated cultural capacity in their communities while enhancing medical palliative care services in a way that respected and integrated with their community cultural practices. This workshop shares the experiences of two First Nations communities who developed palliative care programs by building upon community culture, values and principles. The underlying model guiding development is shared.

Natural Hazard Preparedness in an Auckland Community: Child and Community Perceptions

Science.gov (United States)

Bolton, Patricia; Dirks, Kim; Neuwelt, Pat

2014-01-01

Community engagement in natural hazard preparedness is crucial to ensure sustainable initiatives. Children are important members of communities, and can actively contribute to community preparedness. This article presents research undertaken with 11- to 12-year-old students from a school in Auckland, New Zealand, and leaders associated with the…

From Campuses to Communities: Community-Based Cultism and ...

African Journals Online (AJOL)

Due to the criminal activities of the cult groups in the NDR and ineptitude of the police, communities have responded by creating vigilante groups but this has only promoted cycle of violence. The paper recommended that government should tackle community-based cultism and also strengthen the Nigeria Police Force to be ...

Lived experiences of HIV community workers participating in a community empowerment programme

Directory of Open Access Journals (Sweden)

Juliana Horn

2014-08-01

Objectives: The researcher explored the lived experiences of HIV community workers participating in two CEPs in Ladysmith, KwaZulu-Natal in order to develop recommendations for CEPs. Method: Data were explored using a qualitative hermeneutic phenomenological approach. Ten participants who had been involved in HIV CEPs for more than six months were identified and individual interviews were held. Results: Three themes emerged, namely, giving of yourself, maintaining sustainability and assisting the CEPs and community workers. Each of these themes also contained a number of subthemes. Exploring the lived experience of the community workers revealed that there are a number of ways in which to promote the sustainability of CEPs. Conclusion: The community should be involved in all aspects of the CEP and community workers must respect the community and their knowledge, experience and value systems.

Healthy Native Community Fellowship: An Indigenous Leadership Program to Enhance Community Wellness

Directory of Open Access Journals (Sweden)

Rebecca Rae

2016-11-01

Full Text Available The Healthy Native Communities Fellowship (HNCF is a grassroots evidence-based mentorship and leadership program that develops the skills and community-building capacities of leaders and community teams to improve health status through several intermediate social and cultural mechanisms: (a strengthening social participation (also known as social capital or cohesion; (b strengthening cultural connectedness and revitalization of cultural identity; and (c advocating for health-enhancing policies, practices, and programs that strengthen systems of prevention and care, as well as address the structural social determinants of health. This leadership program uses a community-based participatory research (CBPR approach and participatory evaluation to investigate how the work of local American Indian and Alaska Native leaders (fellows and their community coalitions contributes to individual, family, and community level health outcomes.

National Community Solar Platform

Energy Technology Data Exchange (ETDEWEB)

Rupert, Bart [Clean Energy Collective, Louisville, CO (United States)

2016-06-30

This project was created to provide a National Community Solar Platform (NCSP) portal known as Community Solar Hub, that is available to any entity or individual who wants to develop community solar. This has been done by providing a comprehensive portal to make CEC’s solutions, and other proven community solar solutions, externally available for everyone to access – making the process easy through proven platforms to protect subscribers, developers and utilities. The successful completion of this project provides these tools via a web platform and integration APIs, a wide spectrum of community solar projects included in the platform, multiple groups of customers (utilities, EPCs, and advocates) using the platform to develop community solar, and open access to anyone interested in community solar. CEC’s Incubator project includes web-based informational resources, integrated systems for project information and billing systems, and engagement with customers and users by community solar experts. The combined effort externalizes much of Clean Energy Collective’s industry-leading expertise, allowing third parties to develop community solar without duplicating expensive start-up efforts. The availability of this platform creates community solar projects that are cheaper to build and cheaper to participate in, furthering the goals of DOE’s SunShot Initiative. Final SF 425 Final SF 428 Final DOE F 2050.11 Final Report Narrative

Remote community electrification program - small wind integration in BC's offgrid communities

Energy Technology Data Exchange (ETDEWEB)

Lafaille, Julien [BC Hydro (Canada)

2011-07-01

The paper presents the Remote Community Electrification (RCE) program and wind integration in BC's off grid communities. The program offers electric utility service to eligible remote communities in BC. Most of them are offered off-grid services although it is cheaper to connect a community to a grid. BC hydro serves some communities that are not connected to the main grid. Local diesel or small hydro-generating stations are used to serve remote communities. The renewable energy program target is to reach 50% of remote communities. The reason that wind is a small part of the renewables is that hydro and biomass are abundant in BC. Some other barriers include high installation costs, durability concerns, and lack of in-house technical expertise. Some small Wind initiatives that have been taken were relatively few and fairly small. It can be concluded that due to a poor wind resource and the relatively low cost of diesel, there is limited potential for wind in BC remote communities.

Facilitating communities in designing and using their own community health impact assessment tool

International Nuclear Information System (INIS)

Cameron, Colleen; Ghosh, Sebanti; Eaton, Susan L.

2011-01-01

Reducing health inequities and improving the health of communities require an informed public that is aware of the social determinants of health and how policies and programs have an impact on the health of their communities. People Assessing Their Health (PATH) is a process that uses community-driven health impact assessment to build the capacity of people to become active participants in the decisions that affect the well-being of their community. The PATH process is both a health promotion and a community development approach that builds people's ability to bring critical analysis to a situation and to engage in effective social action to bring about desired change. Because it increases analytical skills and provides communities with their own unique tool to assess the potential impact of projects, programs or policies on the health and well-being of their community it is an empowering process. PATH was originally used in three communities in northeastern Nova Scotia, Canada in 1996 when the Canadian health care system was being restructured to a more decentralized system. Since then it has been used in other communities in Nova Scotia and India. This paper will describe the PATH process and the use of the community health impact assessment as well as the methodology used in the PATH process. The lessons learned from PATH's experiences of building capacity among the community in Canada and India will be presented.

Community Organizing for Healthier Communities: Environmental and Policy Outcomes of a National Initiative.

Science.gov (United States)

Subica, Andrew M; Grills, Cheryl T; Villanueva, Sandra; Douglas, Jason A

2016-12-01

Childhood obesity is disproportionately prevalent in communities of color, partially because of structural inequities in the social and built environment (e.g., poverty, food insecurity, pollution) that restrict healthy eating and active living. Community organizing is an underexamined, grassroots health promotion approach that empowers and mobilizes community residents to advocate for, and achieve, environmental and policy changes to rectify these structural inequities. This paper presents outcomes of the Robert Wood Johnson Foundation's Communities Creating Healthy Environments initiative: the first national program to apply community organizing to combat childhood obesity-causing structural inequities in communities of color. Twenty-one community-based organizations and tribal nations (grantees) conducted 3-year community organizing-based interventions primarily designed to increase children's healthy food and safe recreational access. Grantees' policy wins (environmental and policy changes resulting from grantee interventions) were measured from 2009 to 2014 using semi-structured interviews conducted quarterly and 6 months post-grant, and independently coded and reviewed in 2015 by researchers and expert community organizers. The 21 grantees achieved 72 policy wins (mean=3.43, SD=1.78) across six domains: two directly addressed childhood obesity by enhancing children's healthy food (37.50%) and recreational access (33.33%), whereas four indirectly addressed obesity by promoting access to quality health care (8.33%); clean environments (9.73%); affordable housing (8.33%); and discrimination- and crime-free neighborhoods (2.78%). These findings provide compelling evidence that community organizing-based interventions designed and led by community stakeholders can achieve diverse environmental and policy solutions to the structural inequities that foment childhood obesity in communities of color. Copyright © 2016 American Journal of Preventive Medicine. Published

Communities running energy

International Nuclear Information System (INIS)

Wallace, Paula

2014-01-01

The conditions for the evolution of community renewable energy are right in some parts of the country. This article reports on some recent developments, with opportunities for business and local government. Many communities across Australia are developing wind and solar projects, but only a fraction are actually generating power. Nicky Ison, researcher of community renewable energy (CRE) at the Institute for Sustainable Futures, is director of the Community Power Agency. The latter is behind a new coalition lobbying the federal government in Australia to establish a $50 million grant program to support the development stage of CRE projects.

Bifenthrin causes trophic cascades and alters insect emergence in mesocosms: implication for small streams

Science.gov (United States)

Rogers, Holly; Schmidt, Travis S.; Dabney, Brittanie L.; Hladik, Michelle; Mahler, Barbara J.; Van Metre, Peter C.

2016-01-01

Direct and indirect ecological effects of the widely used insecticide bifenthrin on stream ecosystems are largely unknown. To investigate such effects, a manipulative experiment was conducted in stream mesocosms that were colonized by aquatic insect communities and exposed to bifenthrin-contaminated sediment; implications for natural streams were interpreted through comparison of mesocosm results to a survey of 100 Midwestern streams, USA. In the mesocosm experiment, direct effects of bifenthrin exposure included reduced larval macroinvertebrate abundance, richness, and biomass at concentrations (EC50s ranged 197.6 – 233.5 ng bifenthrin/ g organic carbon) previously thought safe for aquatic life. Indirect effects included a trophic cascade in which periphyton abundance increased after macroinvertebrate scrapers decreased. Adult emergence dynamics and corresponding terrestrial subsidies were altered at all bifenthrin concentrations tested. Extrapolating these results to the Midwestern stream assessment suggests pervasive ecological effects, with altered emergence dynamics likely in 40% of streams and a trophic cascade in 7% of streams. This study provides new evidence that a common pyrethroid might alter aquatic and terrestrial ecosystem function at the regional scale.

Mesocosm validation of the marine No Effect Concentration of dissolved copper derived from a species sensitivity distribution.

Science.gov (United States)

Foekema, E M; Kaag, N H B M; Kramer, K J M; Long, K

2015-07-15

The Predicted No Effect Concentration (PNEC) for dissolved copper based on the species sensitivity distribution (SSD) of 24 marine single species tests was validated in marine mesocosms. To achieve this, the impact of actively maintained concentrations of dissolved copper on a marine benthic and planktonic community was studied in 18 outdoor 4.6m(3) mesocosms. Five treatment levels, ranging from 2.9 to 31μg dissolved Cu/L, were created in triplicate and maintained for 82days. Clear effects were observed on gastropod and bivalve molluscs, phytoplankton, zooplankton, sponges and sessile algae. The most sensitive biological endpoints; reproduction success of the bivalve Cerastoderma edule, copepod population development and periphyton growth were significantly affected at concentrations of 9.9μg Cu/L and higher. The No Observed Effect Concentration (NOEC) derived from this study was 5.7μg dissolved Cu/L. Taking into account the DOC concentration of the mesocosm water this NOEC is comparable to the PNEC derived from the SSD. Copyright © 2015. Published by Elsevier B.V.

Indigenous knowledge systems, local community and community in ...

African Journals Online (AJOL)

The title of the paper requires some brief reflection on the main topics implied. It is appropriate to start off with a definition of Indigenous Knowledge Systems (IKS) as well as a statement regarding the constitutional status of a community. Thereafter I will expand on the merits of IKS towards community development as well as ...

Community Hospital Telehealth Consortium

National Research Council Canada - National Science Library

Williams, Elton

2004-01-01

The Community Hospital Telehealth Consortium is a unique, forward-thinking, community-based healthcare service project organized around 5 not-for-profit community hospitals located throughout Louisiana and Mississippi...

Community Hospital Telehealth Consortium

National Research Council Canada - National Science Library

Williams, Elton

2003-01-01

The Community Hospital Telehealth Consortium is a unique, forward-thinking, community-based healthcare service project organized around 5 not-for-profit community hospitals located throughout Louisiana and Mississippi...

Community Hospital Telehealth Consortium

National Research Council Canada - National Science Library

Williams, Jr, Elton L

2007-01-01

The Community Hospital Telehealth Consortium is a unique, forward-thinking, community-based healthcare service project organized around 5 not-for-profit community hospitals located throughout Louisiana and Mississippi...

Opening the Black Box: Conceptualizing Community Engagement From 109 Community-Academic Partnership Programs.

Science.gov (United States)

Ahmed, Syed M; Maurana, Cheryl; Nelson, David; Meister, Tim; Young, Sharon Neu; Lucey, Paula

2016-01-01

This research effort includes a large scale study of 109 community-academic partnership projects funded by the Healthier Wisconsin Partnership Program (HWPP), a component of the Advancing a Healthier Wisconsin endowment at the Medical College of Wisconsin (MCW) in Milwaukee, Wisconsin. The study provides an analysis unlike other studies, which have been smaller, and/or more narrowly focused in the type of community-academic partnership projects analyzed. To extract themes and insights for the benefit of future community-academic partnerships and the field of community-engaged research (CEnR). Content analysis of the final reports submitted by 109 community-academic partnership projects awards within the time frame of March 2005 to August 2011. Thirteen themes emerged from the report analysis: community involvement, health accomplishments, capacity building, sustainability, collaboration, communication, best practices, administration, relationship building, clarity, adjustment of plan, strategic planning, and time. Data supported previous studies in the importance of some themes, and provided insights regarding how these themes are impactful. The case analysis revealed new insights into the characteristics of these themes, which the authors then grouped into three categories: foundational attributes of successful community-academic partnership, potential challenges of community-academic partnerships, and outcomes of community-academic partnerships. The insights gained from these reports further supports previous research extolling the benefits of community-academic partnerships and provides valuable direction for future partners, funders and evaluators in how to deal with challenges and what they can anticipate and plan for in developing and managing community-academic partnership projects.

Communities defining environmental health: examples from the Colorado (U.S.A.) Healthy Communities Initiative.

Science.gov (United States)

Conner, R F; Tanjasiri, S P

2000-01-01

Communities are increasingly defining 'health' for themselves, then becoming the main actors in actions to improve their health and well being. These community members work from a broad and inclusive definition of 'health' that often incorporates environmental health as a key aspect. They also assume an ecological, or systems, viewpoint that integrates many aspects of the community that affect health and well being, including housing, health, economy, education, transportation, youth and family issues, as well as health and illness care. This paper describes a program that involves 28 large and small, urban and rural communities in the United States state of Colorado that undertook this type of community-based health improvement project. The Colorado Healthy Communities Initiative (CHCI) was designed to bring together citizens in Colorado to work collaboratively to make their communities healthier. This paper describes the program's background, including its principles, processes, and participants, then focuses on the particular aspects of environmental health that communities included in their definitions of a 'healthy community'.

Community interaction and child maltreatment.

Science.gov (United States)

Kim, Bomi; Maguire-Jack, Kathryn

2015-03-01

The way in which parents interact with their environment may have implications for their likelihood of abuse and neglect. This study examines the parent-environment relationship through community involvement and perception, using social disorganization theory. We hypothesize mothers who participate in their communities and have positive perceptions of them may be less likely to maltreat their children because of the potential protective capacity of neighborhood supports. Using information from the 5 year Fragile Families and Child Wellbeing Study (n=2991), the mother's self-reported acts of psychological and physical maltreatment and neglect are measured. A mother's community involvement index is the number of community activities a mother was involved in, and community perception is measured by two five-item Likert scales assessing perception of community collective efficacy. We analyze the relationship between community variables and each of mother's maltreatment behaviors as well as the interaction between community factors using a series of nested logistic regressions. Higher levels of community involvement are associated with lower levels of psychological aggression. More positive perception of community social control is associated with lower levels of physical assault. A moderation effect of community perception suggests that a mother's perception of her community changes the relationship between community involvement and psychological child abuse. The results provide important policy and empirical implications to build positive and supportive communities as a protective factor in child maltreatment. Getting parents involved in their communities can improve the environment in which children and families develop, and decrease the likelihood that maltreatment will occur. Copyright © 2013 Elsevier Ltd. All rights reserved.

Community-Based Programming: An Opportunity and Imperative for the Community College. Institutes & Workshops.

Science.gov (United States)

Boone, Edgar J.

Community-based programming (CBP) is a cooperative process in which a community college serves as the leader and catalyst in effecting collaboration among the people, leaders and community organizations in its service area. This report discusses the changing role of the community college, the nature of CBP, and expected outcomes of the process,…

Mobilizing community energy

International Nuclear Information System (INIS)

Bomberg, Elizabeth; McEwen, Nicola

2012-01-01

What explains the galvanising of communities to participate actively in energy projects? How do groups mobilize to overcome the often formidable barriers highlighted in the existing literature? Drawing on original qualitative research of 100 community energy groups in Scotland, including six in-depth case studies, we explain how effective mobilization occurs and the political dynamics surrounding such mobilization. To capture these dynamics, we adapt theories offered by literature on social movements, with a particular focus on resource mobilization theories. Applying our adapted framework, we identify two particular sets of resources shaping community energy mobilization: (i) structural resources, which refer to the broad political context structuring and constraining opportunities for community energy mobilization; and (ii) symbolic resources—less tangible resources used to galvanise participants. We investigate to what extent our case study groups were able to draw upon and exploit these resources. We find that structural resources can either facilitate or hinder mobilization; what matters is how state resources are exploited and constraints mitigated. The use of symbolic resources was highly effective in aiding mobilization. Each of the groups examined – despite their considerable variation – effectively exploited symbolic resources such as shared identity or desire for strong, self reliant communities. - Highlights: ► Explains how/why community energy groups mobilize and the political dynamics surrounding it. ► Draws on original qualitative research of 100 community energy groups in Scotland. ► Identifies two particular sets of resources (structural and symbolic) and their importance. ► Explains how these resources shape community energy mobilization in Scotland. ► Provides an original application of resource mobilization theory to the field of energy studies.

Single-site community consultation for emergency research in a community hospital setting.

Science.gov (United States)

Galbraith, Kyle L; Keck, Anna-Sigrid; Little, Charletta

2014-01-01

The purpose of this study was to evaluate community member feedback from community consultation and public disclosure activities performed for a clinical investigation involving a device designed to treat traumatic brain injury in prehospital contexts. The clinical investigation of that device was to be performed under the federal regulations providing an exception from prospective informed consent requirements in emergency settings. Secondarily, we sought to assess the community consultation process by measuring the levels of outreach provided by the different communication methods used in these activities, with special attention to the effectiveness of social media for community outreach. The medical device investigation consists of a single-site pilot study based at a 345-bed community hospital in east central Illinois, which also serves as the area's only level I trauma center. Investigators, in collaboration with the local institutional review board, fulfilled community consultation and public disclosure requirements through four public town hall meetings, seven targeted focus groups, targeted mailings to 884 community leaders and researchers, a press conference and press release, internal and external websites, and multiple postings to the hospital's Facebook and Twitter accounts. Community members provided feedback by completing paper or electronic comment cards. A total of 428 community members attended the four town hall meetings and seven focus group sessions. Attendance at each meeting ranged from 4 to 20 attendees for the town hall meetings and 8 to 140 attendees for the focus groups. The investigation's external website received 626 unique visitors and the intranet website received 528 unique visits. Social media postings on Facebook and Twitter received six comments and eight "likes" to indicate that an individual read the posting. In total, attendees completed 175 comment cards to provide their feedback. Community member attitudes regarding the

Collaborative Communities of Firms

DEFF Research Database (Denmark)

2011-01-01

and developing strategic initiatives that aid the community as a whole. We discuss the facilitator role of the shared services provider, contrasting it with the coordinator role found in other multi-firm organizations, and we show how shared services providers function by describing three examples...... is an organizational model called the collaborative community of firms. This chapter addresses an important organizational role in a collaborative community, that of the shared services provider. The shared services provider acts as a facilitator in the community, helping member firms collaborate with one another...... of collaborative communities of firms from different sectors: the U.S.-based Blade.org and two Denmark-based communities, the Kalundborg Industrial Symbiosis and MG50. Implications for the theory and practice of organization design are discussed....

L-Lake macroinvertebrate community

International Nuclear Information System (INIS)

Specht, W.L.

1996-06-01

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

L-Lake macroinvertebrate community

Energy Technology Data Exchange (ETDEWEB)

Specht, W.L.

1996-06-01

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.

Interspecific associations and community structure: A local survey and analysis in a grass community

Directory of Open Access Journals (Sweden)

WenJun Zhang

2014-09-01

Full Text Available Interspecific associations in the plant community may help to understand the self-organizing assembly and succession of the community. In present study, Pearson correlation, net correlation, Spearman rank correlation, and point correlation were used to detect the interspecific (inter-family associations of grass species (families using the sampling data collected in a grass community of Zhuhai, China. We found that most associations between grass species (families were positive associations. The competition/interference/niche separation between grass species (families was not significant. A lot of pairs of grass species and families with statistically significant interspecific (inter-family associations based on four correlation measures were discovered. Cluster trees for grass species/families were obtained by using cluster analysis. Relationship among positive/negative associations, interspecific relationship and community succession/stability/robustness was discussed. I held that species with significant positive or negative associations are generally keystone species in the community. Although both negative and positive associations occur in the community succession, the adaptation and selection will finally result in the successful coexistence of the species with significant positive associations in the climax community. As the advance of community succession, the significant positive associations increase and maximize in climax community, and the significant negative associations increase to a maximum and then decline into climax community. Dominance of significant positive associations in the climax community means the relative stablility and equilibrium of the community. No significant associations usually account for the majority of possible interspecific associations at each phase of community succession. They guarantee the robustness of community. They are candidates of keystone species. Lose of some existing keystone species might be

Ocean acidification alters early successional coral reef communities and their rates of community metabolism.

Directory of Open Access Journals (Sweden)

Sam H C Noonan

Full Text Available Ocean acidification is expected to alter community composition on coral reefs, but its effects on reef community metabolism are poorly understood. Here we document how early successional benthic coral reef communities change in situ along gradients of carbon dioxide (CO2, and the consequences of these changes on rates of community photosynthesis, respiration, and light and dark calcification. Ninety standardised benthic communities were grown on PVC tiles deployed at two shallow-water volcanic CO2 seeps and two adjacent control sites in Papua New Guinea. Along the CO2 gradient, both the upward facing phototrophic and the downward facing cryptic communities changed in their composition. Under ambient CO2, both communities were dominated by calcifying algae, but with increasing CO2 they were gradually replaced by non-calcifying algae (predominantly green filamentous algae, cyanobacteria and macroalgae, which increased from ~30% to ~80% cover. Responses were weaker in the invertebrate communities, however ascidians and tube-forming polychaetes declined with increasing CO2. Differences in the carbonate chemistry explained a far greater amount of change in communities than differences between the two reefs and successional changes from five to 13 months, suggesting community successions are established early and are under strong chemical control. As pH declined from 8.0 to 7.8, rates of gross photosynthesis and dark respiration of the 13-month old reef communities (upper and cryptic surfaces combined significantly increased by 10% and 20%, respectively, in response to altered community composition. As a consequence, net production remained constant. Light and dark calcification rates both gradually declined by 20%, and low or negative daily net calcification rates were observed at an aragonite saturation state of <2.3. The study demonstrates that ocean acidification as predicted for the end of this century will strongly alter reef communities, and

78 FR 13350 - Proposed Collection; Comment Request Healthy Communities Study: How Communities Shape Children's...

Science.gov (United States)

2013-02-27

... community-based initiatives; community characteristics (e.g., school environment); measurements of children... used for the development of future research initiatives targeting childhood obesity. Frequency of... Request Healthy Communities Study: How Communities Shape Children's Health (HCS) Summary: Under the...

Using an academic-community partnership model and blended learning to advance community health nursing pedagogy.

Science.gov (United States)

Ezeonwu, Mabel; Berkowitz, Bobbie; Vlasses, Frances R

2014-01-01

This article describes a model of teaching community health nursing that evolved from a long-term partnership with a community with limited existing health programs. The partnership supported RN-BSN students' integration in the community and resulted in reciprocal gains for faculty, students and community members. Community clients accessed public health services as a result of the partnership. A blended learning approach that combines face-to-face interactions, service learning and online activities was utilized to enhance students' learning. Following classroom sessions, students actively participated in community-based educational process through comprehensive health needs assessments, planning and implementation of disease prevention and health promotion activities for community clients. Such active involvement in an underserved community deepened students' awareness of the fundamentals of community health practice. Students were challenged to view public health from a broader perspective while analyzing the impacts of social determinants of health on underserved populations. Through asynchronous online interactions, students synthesized classroom and community activities through critical thinking. This paper describes a model for teaching community health nursing that informs students' learning through blended learning, and meets the demands for community health nursing services delivery. © 2013 Wiley Periodicals, Inc.

Community Connections. Time Warner Community Responsibility Report, 1998-2000.

Science.gov (United States)

Owens, Jane; Stein, Carol

This report highlights efforts by Time Warner personnel to strengthen community connections through various programs and services aimed at supporting: education, the arts, volunteerism, diversity, and business-community action. The report is divided into sections focusing on each of these areas. The first section, Education, describes programs…

Community-Based Nursing versus Community Health Nursing: What Does It All Mean?

Science.gov (United States)

Zotti, Marianne E.; And Others

1996-01-01

Offers practice models for community-based nursing and community health nursing that demonstrate the different roles, philosophies, and activities of the two approaches. Points to curriculum changes that are needed to prepare students to practice in an increasingly community-oriented health care industry. (Author)

Invasion of nitrite oxidizer dominated communities: interactions between propagule pressure and community composition

DEFF Research Database (Denmark)

Kinnunen, Marta; Dechesne, Arnaud; Albrechtsen, Hans-Jørgen

consider a broader community ecology framework. For example, the effect of propagule pressure, often studied in macro-ecology, has rarely been examined for microbial communities. Also, the interactions between processes governing community assembly and propagule pressure on invasion success have never been...... by nitrite oxidizer strain (Candidatus Nitrotoga sp. HW29) at 3 different propagule pressures. The reactors were then operated another 2 weeks before analyzing community composition by targeted qPCRs and 16S rRNA gene amplicon analysis. We successfully assembled resident communities with different ratios...

76 FR 59706 - Proposed Collection; Comment Request; Healthy Communities Study: How Communities Shape Children's...

Science.gov (United States)

2011-09-27

... published in scientific journals and will be used for the development of future research initiatives... Request; Healthy Communities Study: How Communities Shape Children's Health (HCS) SUMMARY: Under the... control number. Proposed Collection: Title: Healthy Communities Study: How Communities Shape Children's...

76 FR 35452 - Proposed Collection; Comment Request; Healthy Communities Study: How Communities Shape Children's...

Science.gov (United States)

2011-06-17

... scientific journals and will be used for the development of future research initiatives targeting childhood... Request; Healthy Communities Study: How Communities Shape Children's Health (HCS) SUMMARY: In compliance... Collection: Title: Healthy Communities Study: How Communities Shape Children's Health (HCS). Type of...

Community interventions for cardiovascular disease.

Science.gov (United States)

Parker, Donna R; Assaf, Annlouise R

2005-12-01

Review of the community-based CVD intervention programs suggests that a number of components have been successful using varying methods and materials for CVD risk reduction. It should be noted, however, that in multi-intervention programs it is often difficult to determine which components of the intervention were responsible for the overall success of the study. The community-based approach to CVD prevention is generalizable, cost-effective (because of the use of mass communication methods), and has the potential for modifying the environment and influencing health policies. Based on the experiences and successes of a number of community projects, recommendations have been proposed for developing future programs. Although they are not totally comprehensive, it has been suggested that a community-based intervention program should consider the following recommendations: 1) An understanding of the community: the needs and priorities of the community should be assessed, and close collaboration with individuals from the community, including community leaders, opinion leaders, community health care providers, and community organizations from various sectors of the community, should be consulted. Efforts should be focused on underserved and vulnerable populations. 2) Inclusion of community activities: these activities should be integrated within the context of the community environment, including primary health care services, voluntary organizations, grocery stores, restaurants, work sites, schools, and local media. 3) Inclusion mass media messages: the mass media can provide information and reinforcement of the behavior change. 4) Develop cost-effective interventions to assure that the community is exposed to an effective dose of the intervention. 5) Work with community organizations to help change social and physical environments to make them more conducive to health and healthy life-styles changes. 6) Develop a reliable monitoring and evaluation system: monitor the

Empowering community settings: agents of individual development, community betterment, and positive social change.

Science.gov (United States)

Maton, Kenneth I

2008-03-01

The pathways and processes through which empowering community settings influence their members, the surrounding community and the larger society are examined. To generate the proposed pathways and processes, a broad range of studies of community settings were reviewed, in the domains of adult well-being, positive youth development, locality development, and social change. A set of organizational characteristics and associated processes leading to member empowerment across domains were identified, as well as three pathways through which empowering settings in each domain contribute to community betterment and positive social change. The paper concludes with an examination of the ways that community psychology and allied disciplines can help increase the number and range of empowering settings, and enhance the community and societal impact of existing ones.

Community-Based Ecotourism: The Transformation of Local Community

Directory of Open Access Journals (Sweden)

Pookhao Nantira

2014-01-01

Full Text Available Community-based ecotourism (CBET is considered a sustainable form of tourism that improves the quality of life of hosts at the tourist destination. Scholars have yet to explore the long-term operation of CBET in relation to its effects on the local way of life. Consequently, the purpose of this paper is to examine the transformation of a local community due to the operation of CBET in relation to sociocultural, economic and environmental aspects. The findings reveal that the community encounters both positive and negative impacts of transformation. However, unintended impacts of the CBET operation lay embedded in the transformation of relationships among the community members. The study identifies that close relationships among the villagers has been initially transformed to loose relationships due to forgotten communal goals; CBET has transformed from being a conservation tool to being a business-oriented goal which causes conflicts of interest among local people and alters traditional social structure. The study also agrees with the notion of social exchange theory for villagers to enhance environmental sustainability, and proposes that slight inequalities of benefits received from CBET causes social transformation at the local level.

Predicting bed shear stress and its role in sediment dynamics and restoration potential of the Everglades and other vegetated flow systems

Science.gov (United States)

Larsen, Laurel G.; Harvey, Judson; Crimaldi, John P.

2009-01-01

Entrainment of sediment by flowing water affects topography, habitat suitability, and nutrient cycling in vegetated floodplains and wetlands, impacting ecosystem evolution and the success of restoration projects. Nonetheless, restoration managers lack simple decision-support tools for predicting shear stresses and sediment redistribution potential in different vegetation communities. Using a field-validated numerical model, we developed state-space diagrams that provide these predictions over a range of water-surface slopes, depths, and associated velocities in Everglades ridge and slough vegetation communities. Diminished bed shear stresses and a consequent decrease in bed sediment redistribution are hypothesized causes of a recent reduction in the topographic and vegetation heterogeneity of this ecosystem. Results confirmed the inability of present-day flows to entrain bed sediment. Further, our diagrams showed bed shear stresses to be highly sensitive to emergent vegetation density and water-surface slope but less sensitive to water depth and periphyton or floating vegetation abundance. These findings suggested that instituting a pulsing flow regime could be the most effective means to restore sediment redistribution to the Everglades. However, pulsing flows will not be sufficient to erode sediment from sloughs with abundant spikerush, unless spikerush density first decreases by natural or managed processes. Our methods provide a novel tool for identifying restoration parameters and performance measures in many types of vegetated aquatic environments where sediment erosion and deposition are involved.

Community Engagement in a Graduate-Level Community Literacy Course

Science.gov (United States)

Marshall Bowen, Lauren; Arko, Kirsti; Beatty, Joel; Delaney, Cindy; Dorpenyo, Isidore; Moeller, Laura; Roberts, Elsa; Velat, John

2014-01-01

A case study of a graduate-level community literacy seminar that involved a tutoring project with adult digital literacy learners, this essay illustrates the value of community outreach and service-learning for graduate students in writing studies. Presenting multiple perspectives through critical reflection, student authors describe how their…

A phylogenetic community approach for studying termite communities in a West African savannah.

Science.gov (United States)

Hausberger, Barbara; Korb, Judith

2015-10-01

Termites play fundamental roles in tropical ecosystems, and mound-building species in particular are crucial in enhancing species diversity, from plants to mammals. However, it is still unclear which factors govern the occurrence and assembly of termite communities. A phylogenetic community approach and null models of species assembly were used to examine structuring processes associated with termite community assembly in a pristine savannah. Overall, we did not find evidence for a strong influence of interspecific competition or environmental filtering in structuring these communities. However, the presence of a single species, the mound-building termite Macrotermes bellicosus, left a strong signal on structuring and led to clustered communities of more closely related species. Hence, this species changes the assembly rules for a whole community. Our results show the fundamental importance of a single insect species for community processes, suggesting that more attention to insect species is warranted when developing conservation strategies. © 2015 The Author(s).

Community-based research in action: tales from the Ktunaxa community learning centres project.

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Stacy, Elizabeth; Wisener, Katherine; Liman, Yolanda; Beznosova, Olga; Lauscher, Helen Novak; Ho, Kendall; Jarvis-Selinger, Sandra

2014-01-01

Rural communities, particularly Aboriginal communities, often have limited access to health information, a situation that can have significant negative consequences. To address the lack of culturally and geographically relevant health information, a community-university partnership was formed to develop, implement, and evaluate Aboriginal Community Learning Centres (CLCs). The objective of this paper is to evaluate the community-based research process used in the development of the CLCs. It focuses on the process of building relationships among partners and the CLC's value and sustainability. Semistructured interviews were conducted with key stakeholders, including principal investigators, community research leads, and supervisors. The interview transcripts were analyzed using an open-coding process to identify themes. Key challenges included enacting shared project governance, negotiating different working styles, and hiring practices based on commitment to project objectives rather than skill set. Technological access provided by the CLCs increased capacity for learning and collective community initiatives, as well as building community leads' skills, knowledge, and self-efficacy. An important lesson was to meet all partners "where they are" in building trusting relationships and adapting research methods to fit the project's context and strengths. Successful results were dependent upon persistence and patience in working through differences, and breaking the project into achievable goals, which collectively contributed to trust and capacity building. The process of building these partnerships resulted in increased capacity of communities to facilitate learning and change initiatives, and the capacity of the university to engage in successful research partnerships with Aboriginal communities in the future.

Caring for the community.

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Spitzer, Roxane

2004-01-01

Nurses can play a unique role in caring for their communities. The first and most obvious role is the direct care of patients, the underlying raison d'etre of nursing, and second is the indirect care of the patients' families and friends. The hands-on healing image of nurses is held by many people and personified through the years by such real-life examples as Clara Barton. It is also the image that attracts many to nursing and is fueled by desire--the desire to help, to make a positive difference, and to serve people. It is often a powerful one-on-one connection between caregiver and receiver, nurse and patient, that defines the role of nursing. Yet, nurses can--and should--play broader roles in caring for their communities. This includes the internal community within one's own organization, the environment in which nurses work, and the larger external community--or communities--in which one lives. By reaching out and caring for the broader communities, nurses have the opportunity to grow while the communities benefit from their participatory caring. In addition, the image of nursing is enhanced externally. The nurse as community caregiver melds the heart and soul of nursing for a new 21st century model of caring.

Cyanobacteria dominance influences resource use efficiency and community turnover in phytoplankton and zooplankton communities.

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Filstrup, Christopher T; Hillebrand, Helmut; Heathcote, Adam J; Harpole, W Stanley; Downing, John A

2014-04-01

Freshwater biodiversity loss potentially disrupts ecosystem services related to water quality and may negatively impact ecosystem functioning and temporal community turnover. We analysed a data set containing phytoplankton and zooplankton community data from 131 lakes through 9 years in an agricultural region to test predictions that plankton communities with low biodiversity are less efficient in their use of limiting resources and display greater community turnover (measured as community dissimilarity). Phytoplankton resource use efficiency (RUE = biomass per unit resource) was negatively related to phytoplankton evenness (measured as Pielou's evenness), whereas zooplankton RUE was positively related to phytoplankton evenness. Phytoplankton and zooplankton RUE were high and low, respectively, when Cyanobacteria, especially Microcystis sp., dominated. Phytoplankton communities displayed slower community turnover rates when dominated by few genera. Our findings, which counter findings of many terrestrial studies, suggest that Cyanobacteria dominance may play important roles in ecosystem functioning and community turnover in nutrient-enriched lakes. © 2014 John Wiley & Sons Ltd/CNRS.

Career guidance in communities

DEFF Research Database (Denmark)

Thomsen, Rie

for the development of a critically reflexive career guidance practice. The considerations are organised around seven elements. 1. Creating opportunity, structure and access 2. Entering a community and increasing visibility 3. Providing guidance in communities 4. Exploring potentials in guidance situations 5...... in career guidance practices as well as in the lives of the people in the communities. This paper falls into two parts: The first part considers the collective as the starting point for the development of meaningful career guidance activities. Based on previous research on career guidance in communities......The aim of this paper is to inspire practitioners and professionals to leave their offices to bring career guidance into communities that might not identify with career guidance in the first instance. By making the effort to engage with communities, practitioners may bring about a critical change...

Coal, culture and community

Energy Technology Data Exchange (ETDEWEB)

NONE

1993-11-01

16 papers are presented with the following titles: the miners; municipalisation and the millenium - Bolton-upon-Dearne Urban District Council 1899-1914; the traditional working class community revisited; the cultural capital of coal mining communities; activities, strike-breakers and coal communities; the limits of protest - media coverage of the Orgreave picket during the miners` strike; in defence of home and hearth? Families, friendships and feminism in mining communities; young people`s attitudes to the police in mining communities; the determinants of productivity growth in the British coal mining industry, 1976-1989; strategic responses to flexibility - a case study in coal; no coal turned in Yorkshire?; the North-South divide in the Central Coalfields; the psychological effects of redundancy and worklessness - a case study from the coalfields; the Dearne Valley initiative; the future under labour: and coal, culture and the community.

Responding to Community Needs through Community Follow-Up. Junior College Resource Review.

Science.gov (United States)

Mehallis, Mantha Vlahos

This literature review examines the utilization of community needs assessment data in program planning and evaluation efforts at community colleges. The review first defines and looks at the purposes of community needs assessments, noting that while such studies are purported to facilitate the planning and evaluation of credit and non-credit…

Community Social Organization: A Conceptual Linchpin in Examining Families in the Context of Communities

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Mancini, Jay A.; Bowen, Gary L.; Martin, James A.

2005-01-01

The concept of social organization provides an important framework for understanding families in the context of communities and focuses our attention on norms, networks, and associated processes that typify community life. We discuss the significance of community for understanding family outcomes, discuss challenges in defining community context,…

Contextual community prevention theory: building interventions with community agency collaboration.

Science.gov (United States)

Morales, Eduardo S

2009-11-01

Translation from research to practice faces numerous problems that include replicating effectiveness, fidelity to the protocol and processes, and adaptations to different types of target populations. Working collaboratively with existing service providers can speed up the time for development and can ease the implementation of empirical randomized trials. Contextual community prevention theory is an innovative approach that focuses on changing behaviors of community members by creating a visible institutional presence that draws and pulls the targeted population into the organization's activities and interventions. The result is an institution or organization within the community that provides a new active and dynamic context, engaging its community members into its activities, interventions, and functions. An HIV prevention program developed collaboratively from the ground up for Latino gay/bisexual men is presented. Results from the program evaluation efforts across the years suggest promise for testing its efficacy through a randomized trial. HIV prevention efforts need to develop dynamic support systems within communities where these men have ownership, have control, and feel safe; otherwise HIV infection rates in this population will increase. Copyright 2009 by the American Psychological Association

Promoting Community Health and Eliminating Health Disparities Through Community-Based Participatory Research.

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Xia, Ruiping; Stone, John R; Hoffman, Julie E; Klappa, Susan G

2016-03-01

In physical therapy, there is increasing focus on the need at the community level to promote health, eliminate disparities in health status, and ameliorate risk factors among underserved minorities. Community-based participatory research (CBPR) is the most promising paradigm for pursuing these goals. Community-based participatory research stresses equitable partnering of the community and investigators in light of local social, structural, and cultural elements. Throughout the research process, the CBPR model emphasizes coalition and team building that joins partners with diverse skills/expertise, knowledge, and sensitivities. This article presents core concepts and principles of CBPR and the rationale for its application in the management of health issues at the community level. Community-based participatory research is now commonly used to address public health issues. A literature review identified limited reports of its use in physical therapy research and services. A published study is used to illustrate features of CBPR for physical therapy. The purpose of this article is to promote an understanding of how physical therapists could use CBPR as a promising way to advance the profession's goals of community health and elimination of health care disparities, and social responsibility. Funding opportunities for the support of CBPR are noted. © 2016 American Physical Therapy Association.

Community participation and mental health during retirement in community sample of Australians.

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Olesen, Sarah C; Berry, Helen L

2011-03-01

This study considered whether community participation during later adulthood is more strongly associated with mental health during retirement than it is while in employment; i.e. in the absence of paid work. Participants were 322 men and 311 women aged 45 years and older, who were part of a random sample of an Australian coastal community. The frequency of participation across 14 types of community-based activities was assessed. Overall mental health was measured on a 10-item Kessler Psychological Distress Scale. Linear regression models tested the multivariate associations between distress and community participation, and whether this association differed for retired and working people. Retirees did not participate in their communities more than working people. The association between community participation and psychological distress did not differ by retirement status when people of all ages were considered together; however, stronger associations between several activities and (less) distress were found for retirees compared to their working peers in a younger cohort (aged 45 to 54). This cohort coincides with the average age of transition to retirement in Australia. These findings offer some support for the view that community participation may assist in managing the mental health implications of the transition from work to retirement.

Community Challenge Grantees

Data.gov (United States)

Department of Housing and Urban Development — HUD's Community Challenge Grants aim to reform and reduce barriers to achieving affordable, economically vital and sustainable communities. The funds are awarded to...

The meaning of community involvement in health: the perspective of primary health care communities

Directory of Open Access Journals (Sweden)

GG Mchunu

2005-09-01

Full Text Available The goal of this study was to establish the understanding and appreciation of the essence of PHC principles in the two Primary Health Care (PHC communities. The PHC communities in this study referred to the people who were involved in the operation of the phenomenon, that is health professionals working in the health care centers and the communities served by these health care centers. It was hoped that the study would enhance the understanding of the importance of community involvement in health (CIH in health care delivery, for both community members and health professionals. A case study method was used to conduct the study. Two community health centers in the Ethekwini health district, in Kwa Zulu Natal, were studied. One health center was urban based, the other was rural based. A sample of 31 participants participated in the study. The sample comprised of 8 registered nurses, 2 enrolled nurses, 13 community members and 8 community health workers. Data was collected using individual interviews and focus groups, and was guided by the case study protocol. The findings of the study revealed that in both communities, participants had different, albeit complementary, understanding of the term ‘Community Involvement in Health’ (CIH. Essentially, for these participants, CIH meant collaboration, co-operation and involvement in decision-making.

EarthConnections: Integrating Community Science and Geoscience Education Pathways for More Resilient Communities.

Science.gov (United States)

Manduca, C. A.

2017-12-01

To develop a diverse geoscience workforce, the EarthConnections collective impact alliance is developing regionally focused, Earth education pathways. These pathways support and guide students from engagement in relevant, Earth-related science at an early age through the many steps and transitions to geoscience-related careers. Rooted in existing regional activities, pathways are developed using a process that engages regional stakeholders and community members with EarthConnections partners. Together they connect, sequence, and create multiple learning opportunities that link geoscience education and community service to address one or more local geoscience issues. Three initial pilots are demonstrating different starting points and strategies for creating pathways that serve community needs while supporting geoscience education. The San Bernardino pilot is leveraging existing academic relationships and programs; the Atlanta pilot is building into existing community activities; and the Oklahoma Tribal Nations pilot is co-constructing a pathway focus and approach. The project is using pathway mapping and a collective impact framework to support and monitor progress. The goal is to develop processes and activities that can help other communities develop similar community-based geoscience pathways. By intertwining Earth education with local community service we aspire to increase the resilience of communities in the face of environmental hazards and limited Earth resources.

Knowledge Communities in fives

NARCIS (Netherlands)

Andriessen, J.H.E.

2006-01-01

Many modern knowledge intensive organisations rely on knowledge sharing communities, often called ‘communities of practice. These communities can be found in many organisations, but their forms and functions appear to be quite diverse. This implies that questions concerning the functioning of

The Persistence of Neighboring as a Determinant of Community Attachment: A Community Field Perspective

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Sundblad, Daniel R.; Sapp, Stephen G.

2011-01-01

We examined the community field perspective as a complement to the linear-development and systemic models of community attachment, wherein community attachment is defined as a social bond to the community of place. We empirically evaluated indicators of the actor's interaction within the social field, such as the perceived quality of neighboring…

Community Vitality: The Role of Community-Level Resilience Adaptation and Innovation in Sustainable Development

Directory of Open Access Journals (Sweden)

Lenore Newman

2010-01-01

Full Text Available Community level action towards sustainable development has emerged as a key scale of intervention in the effort to address our many serious environmental issues. This is hindered by the large-scale destruction of both urban neighbourhoods and rural villages in the second half of the twentieth century. Communities, whether they are small or large, hubs of experimentation or loci of traditional techniques and methods, can be said to have a level of community vitality that acts as a site of resilience, adaptation and innovation in the face of environmental challenges. This paper outlines how community vitality acts as a cornerstone of sustainable development and suggests some courses for future research. A meta-case analysis of thirty-five Canadian communities reveals the characteristics of community vitality emerging from sustainable development experiments and its relationship to resilience, applied specifically to community development.

Engaging the Deaf American Sign Language Community: Lessons From a Community-Based Participatory Research Center

Science.gov (United States)

McKee, Michael; Thew, Denise; Starr, Matthew; Kushalnagar, Poorna; Reid, John T.; Graybill, Patrick; Velasquez, Julia; Pearson, Thomas

2013-01-01

Background Numerous publications demonstrate the importance of community-based participatory research (CBPR) in community health research, but few target the Deaf community. The Deaf community is understudied and underrepresented in health research despite suspected health disparities and communication barriers. Objectives The goal of this paper is to share the lessons learned from the implementation of CBPR in an understudied community of Deaf American Sign Language (ASL) users in the greater Rochester, New York, area. Methods We review the process of CBPR in a Deaf ASL community and identify the lessons learned. Results Key CBPR lessons include the importance of engaging and educating the community about research, ensuring that research benefits the community, using peer-based recruitment strategies, and sustaining community partnerships. These lessons informed subsequent research activities. Conclusions This report focuses on the use of CBPR principles in a Deaf ASL population; lessons learned can be applied to research with other challenging-to-reach populations. PMID:22982845

75 FR 11641 - Community Reinvestment Act; Interagency Questions and Answers Regarding Community Reinvestment...

Science.gov (United States)

2010-03-11

... Financial Institutions (CDFIs), New Markets Tax Credit-eligible Community Development Entities, Community... Financial Institutions Examination Council (FFIEC) in 1996 (61 FR 54647), and were last revised on January 6... represented financial institutions and their trade associations, community development advocates and...

Methylmercury bioaccumulation in stream food webs declines with increasing primary production

Science.gov (United States)

Walters, David; D.F. Raikow,; C.R. Hammerschmidt,; M.G. Mehling,; A. Kovach,; J.T. Oris,

2015-01-01

Opposing hypotheses posit that increasing primary productivity should result in either greater or lesser contaminant accumulation in stream food webs. We conducted an experiment to evaluate primary productivity effects on MeHg accumulation in stream consumers. We varied light for 16 artificial streams creating a productivity gradient (oxygen production =0.048–0.71 mg O2 L–1 d–1) among streams. Two-level food webs were established consisting of phytoplankton/filter feeding clam, periphyton/grazing snail, and leaves/shredding amphipod (Hyalella azteca). Phytoplankton and periphyton biomass, along with MeHg removal from the water column, increased significantly with productivity, but MeHg concentrations in these primary producers declined. Methylmercury concentrations in clams and snails also declined with productivity, and consumer concentrations were strongly correlated with MeHg concentrations in primary producers. Heterotroph biomass on leaves, MeHg in leaves, and MeHg in Hyalella were unrelated to stream productivity. Our results support the hypothesis that contaminant bioaccumulation declines with stream primary production via the mechanism of bloom dilution (MeHg burden per cell decreases in algal blooms), extending patterns of contaminant accumulation documented in lakes to lotic systems.

Designing to support community gardens by going beyond community gardens

NARCIS (Netherlands)

Wang, X.; Wakkary, R.; Rau, P.-L.P.

2017-01-01

Community gardens connect to many organizations in order to receive and offer resources and services. The complex sociotechnical systems in which community gardens inhabit bring both opportunities and challenges for designers who endeavor to support them. In this study, we investigated three

Perspectives on community gardens, community kitchens and the Good Food Box program in a community-based sample of low-income families.

Science.gov (United States)

Loopstra, Rachel; Tarasuk, Valerie

2013-01-08

Growing recognition of the problem of household food insecurity in Canada has meant public health practitioners are looking for effective ways to ameliorate this problem in their communities. Community gardens, community kitchens, and food box programs can offer nutritious foods for comparably lower costs, however, the uptake and perceptions of these programs in populations at risk of food insecurity have not been evaluated. Building on a previous finding of low program participation among 485 families living in high-poverty neighbourhoods in Toronto, the objective of this study was to understand reasons for non-participation. One year after the baseline study, 371 families were interviewed a second time and were asked to provide their reasons for not participating in community gardens, community kitchens, or the Good Food Box program. Responses were analyzed by inductive content analysis. At follow-up, only 12 families had participated in a community garden, 16 in a community kitchen, and 4 in the Good Food Box program. Reasons for non-participation grouped under two themes. First, families expressed that programs were not accessible because they lacked the knowledge of how or where to participate or because programs were not in their neighbourhoods. Second, programs lacked fit for families, as they were not suited to busy schedules, interests, or needs. This study provides unique perspective on participation in community food programs among food-insecure families and suggests that these programs may not be effective options for these families to improve their food access.

Engaging community volunteers in participatory action research in Tāmaki community of Auckland, New Zealand.

Science.gov (United States)

Andajani-Sutjahjo, Sari; Liew, Theresa C H; Smith, John F; Esekielu, Iutita; Mason, Gabrielle; Tariu, Imele

2018-04-01

This article discusses the experiences of community volunteers' participation in a community-based participatory research project in Tāmaki, a low socio-economic and ethnically diverse suburban community within greater Auckland City, New Zealand. In the Tāmaki Community Action Research project, community volunteers were recruited and trained to conduct random household surveys (RHS) and asset mapping commissioned by community groups and government agencies in that area. The volunteers were involved in planning, coordination and ongoing governance of the project and ∼70 residents and local university students participated at different stages of the 2-year project. Over 600 RHS were completed and the volunteers' experiences were recorded in field notes, informal group discussions, daily team meetings and individual interviews and form the basis of this article. Only their experiences are discussed here, not the survey results which will be presented elsewhere. The project reflected the inherent asset-rich nature of the community via examples of individual volunteer empowerment and collective social/community capacity building. Volunteers increased their interpersonal and organizational skills, their understanding of the complexity of their community's logistics and cultural diversity, and gained an increased sense of community purpose and commitment. There was very strong endorsement of culturally sensitive research practice to recognize cultural differences and to engage productively within their richly ethnically diverse community. Full community volunteer participation in the project's governance (i.e. through design, training, implementation and ongoing consultation/management phases) was considered key to sustaining the life of project.

A community-based intervention to build community harmony in an Indigenous Guatemalan Mining Town.

Science.gov (United States)

Caxaj, Claudia Susana; Parroquia de San Miguel Ixtahuacan, Kolol Qnan Tx'otx'

2018-01-24

The presence of large-scale mining operations poses many threats to communities. In a rural community in Guatemala, community leaders were motivated to address divisiveness and local conflict that have been exacerbated since the arrival of a mining company in the region. Prior research by our team identified spiritual and cultural strengths as important sources of strength and resilience in the community. We piloted a community-based intervention centred on spiritual and cultural practices in the region, to address divisiveness and build community harmony. One hundred and seventeen participants from over 18 villages in the municipality participated in the workshops and follow-up focus groups. Community leaders facilitated the intervention and partnered with the academic researcher throughout the research process. Overall, community members and facilitators expressed satisfaction with the workshop. Further, our analysis revealed three important processes important to the development of community harmony in the region: (a) mutual recognition and collectivisation; (b) affirmation of ancestral roots and connections to Mother Earth and (c) inspiring action and momentum towards solutions. These mechanisms, and the socio-political contexts that undermine them, have important implications for how global health programmes are developed and how collective processes for well-being are understood within an inequitable, conflict-laden world.

Asset mapping for an Asian American community: Informal and formal resources for community building

Directory of Open Access Journals (Sweden)

Suzie S. Weng

2016-04-01

Full Text Available With the growth of the Asian American population in the Southern region of the United States, mainstream and Asian American community must be aware of both informal and formal supports that are available for the population in order to effectively address needs and allocate resources. This community-based project identified informal and mainstream support that is available to an Asian American community using asset mapping. The asset-based community development framework was used in which the capacities of the local people and their associations are recognized to be essential in building a more powerful community, to helping a community be more self-sustaining, and to developing better relationships among entities. This study provides an inventory of community assets that otherwise may have been ignored and thus has the potential to contribute to a better functioning Asian American community in Jacksonville, Florida. 719 assets were identified as available potential resources for members of the Asian American community with a majority as formal resources. Of the informal assets, a majority are organizations. In general, formal resources are centralized, whereas informal resources are more evenly distributed throughout the city. These results can contribute to the establishment of more culturally accessible services and utilization of services.

American Indian Community Colleges.

Science.gov (United States)

One Feather, Gerald

With the emergence of reservation based community colleges (th Navajo Community College and the Dakota Community Colleges), the American Indian people, as decision makers in these institutions, are providing Indians with the technical skills and cultural knowledge necessary for self-determination. Confronted with limited numbers of accredited…

A controlled community-based trial to promote smoke-free policy in rural communities.

Science.gov (United States)

Hahn, Ellen J; Rayens, Mary Kay; Adkins, Sarah; Begley, Kathy; York, Nancy

2015-01-01

Rural, tobacco-growing areas are disproportionately affected by tobacco use, secondhand smoke, and weak tobacco control policies. The purpose was to test the effects of a stage-specific, tailored policy-focused intervention on readiness for smoke-free policy, and policy outcomes in rural underserved communities. A controlled community-based trial including 37 rural counties. Data were collected annually with community advocates (n = 330) and elected officials (n = 158) in 19 intervention counties and 18 comparison counties over 5 years (average response rate = 68%). Intervention communities received policy development strategies from community advisors tailored to their stage of readiness and designed to build capacity, build demand, and translate and disseminate science. Policy outcomes were tracked over 5 years. Communities receiving the stage-specific, tailored intervention had higher overall community readiness scores and better policy outcomes than the comparison counties, controlling for county-level smoking rate, population size, and education. Nearly one-third of the intervention counties adopted smoke-free laws covering restaurants, bars, and all workplaces compared to none of the comparison counties. The stage-specific, tailored policy-focused intervention acted as a value-added resource to local smoke-free campaigns by promoting readiness for policy, as well as actual policy change in rural communities. Although actual policy change and percent covered by the policies were modest, these areas need additional resources and efforts to build capacity, build demand, and translate and disseminate science in order to accelerate smoke-free policy change and reduce the enormous toll from tobacco in these high-risk communities. © 2014 National Rural Health Association.

Trust and community. Exploring the meanings, contexts and dynamics of community renewable energy

Energy Technology Data Exchange (ETDEWEB)

Walker, Gordon [University of Lancaster, Department of Geography, Lancaster LA1 4YN (United Kingdom); Devine-Wright, Patrick [University of Manchester, The School of Environment and Development, Humanities Bridgeford Street Building, Oxford Road, Manchester M13 9PL (United Kingdom); Hunter, Sue; High, Helen; Evans, Bob [University of Lancaster, Department of Geography, Lancaster LA1 4YN (United Kingdom); University of Manchester, The School of Environment and Development, Humanities Bridgeford Street Building, Oxford Road, Manchester M13 9PL (United Kingdom)

2010-06-15

Community renewable energy projects have recently been promoted and supported in the UK by government policy. A community approach, it is argued in the rhetoric of both government and grassroots activists will change the experience and outcomes of the energy sustainable technology implementation. In this paper, we consider how interpersonal and social trust is implicated in the different meanings given to community in RE programmes and projects, and in the qualities and outcomes that are implied or assumed by taking a community approach. We examine how these meanings play out in examples of projects on the ground, focusing on two contrasting cases in which the relationships between those involved locally have exhibited different patterns of cohesiveness and fracture. We argue that trust does have a necessary part to play in the contingencies and dynamics of community RE projects and in the outcomes they can achieve. Trust between local people and groups that take projects forward is part of the package of conditions which can help projects work. Whilst trust may therefore be functional for the development of community RE and potentially can be enhanced by the adoption of a community approach, this cannot be either assured or assumed under the wide diversity of contexts, conditions and arrangements under which community RE is being pursued and practiced. (author)

Trust and community: Exploring the meanings, contexts and dynamics of community renewable energy

Energy Technology Data Exchange (ETDEWEB)

Walker, Gordon, E-mail: g.p.walker@lancaster.ac.u [University of Lancaster, Department of Geography, Lancaster LA1 4YN (United Kingdom); Devine-Wright, Patrick [University of Manchester, School of Environment and Development, Humanities Bridgeford Street Building, Oxford Road, Manchester M13 9PL (United Kingdom); Hunter, Sue; High, Helen; Evans, Bob [University of Lancaster, Department of Geography, Lancaster LA1 4YN (United Kingdom); University of Manchester, School of Environment and Development, Humanities Bridgeford Street Building, Oxford Road, Manchester M13 9PL (United Kingdom)

2010-06-15

Community renewable energy projects have recently been promoted and supported in the UK by government policy. A community approach, it is argued in the rhetoric of both government and grassroots activists will change the experience and outcomes of the energy sustainable technology implementation. In this paper, we consider how interpersonal and social trust is implicated in the different meanings given to community in RE programmes and projects, and in the qualities and outcomes that are implied or assumed by taking a community approach. We examine how these meanings play out in examples of projects on the ground, focusing on two contrasting cases in which the relationships between those involved locally have exhibited different patterns of cohesiveness and fracture. We argue that trust does have a necessary part to play in the contingencies and dynamics of community RE projects and in the outcomes they can achieve. Trust between local people and groups that take projects forward is part of the package of conditions which can help projects work. Whilst trust may therefore be functional for the development of community RE and potentially can be enhanced by the adoption of a community approach, this cannot be either assured or assumed under the wide diversity of contexts, conditions and arrangements under which community RE is being pursued and practiced.

Trust and community: Exploring the meanings, contexts and dynamics of community renewable energy

International Nuclear Information System (INIS)

Walker, Gordon; Devine-Wright, Patrick; Hunter, Sue; High, Helen; Evans, Bob

2010-01-01

Community renewable energy projects have recently been promoted and supported in the UK by government policy. A community approach, it is argued in the rhetoric of both government and grassroots activists will change the experience and outcomes of the energy sustainable technology implementation. In this paper, we consider how interpersonal and social trust is implicated in the different meanings given to community in RE programmes and projects, and in the qualities and outcomes that are implied or assumed by taking a community approach. We examine how these meanings play out in examples of projects on the ground, focusing on two contrasting cases in which the relationships between those involved locally have exhibited different patterns of cohesiveness and fracture. We argue that trust does have a necessary part to play in the contingencies and dynamics of community RE projects and in the outcomes they can achieve. Trust between local people and groups that take projects forward is part of the package of conditions which can help projects work. Whilst trust may therefore be functional for the development of community RE and potentially can be enhanced by the adoption of a community approach, this cannot be either assured or assumed under the wide diversity of contexts, conditions and arrangements under which community RE is being pursued and practiced.

Marketing of the online communities

OpenAIRE

Pražan, Jan

2010-01-01

The Bachelor Thesis "Marketing of the online communities" is devoted to online virtual communities, one of the phenomena of the current Internet. Goal of this thesis is to determine the factors that predispose the successful operation of online communities. The thesis defines the essentials features of social media, characterized by online communities and their role in marketing. It deals with strategic and tactical aspects of building and maintaining successful online communities. Based on t...

Source Materials for the Healthy Communities Toolkit: A Resource Guide for Community and Faith-Based Organizations.

Science.gov (United States)

Acosta, Joie; Chandra, Anita; Williams, Malcolm; Davis, Lois M

2011-01-01

The Patient Protection and Affordable Care Act places significant emphasis on the role of community-based health promotion initiatives; within this focus, community and faith-based organizations (CFBOs) are seen as critical partners for improving community well-being. This article describes a report that provides the content for a toolkit that will prepare community and faith-based organizations to take advantage of opportunities presented in the Patient Protection and Affordable Care Act and engage faith and community leaders in promoting health in their communities. This includes key facts and figures about health topics, handouts for community groups, and web links for resources and other information in the following areas: healthcare reform; community health centers and development of the community health workforce; promotion of healthy families; mental health; violence and trauma; prevention of teen and unintended pregnancy and HIV/AIDS; and chronic disease prevention. The report also includes recommendations for testing the content of the toolkit with communities and considerations for its implementation.

ANTI-DISCRIMINATORY PRACTICE AND COMMUNITY DEVELOPMENT : A case study of a clubhouse community

OpenAIRE

Louko, Tiina

2011-01-01

Louko, Tiina. Anti-discriminatory practice and community development - A case study of a clubhouse community. Järvenpää, Spring 2011, 54 p. Diaconia University of Applied Sciences, Diak South Järvenpää. Degree Programme in Social Services. Bachelor´s Degree in Social Services. This study was conducted in the context of Eastern Helsinki Clubhouse, which is a community for mental health rehabilitees. The purpose of the research was to describe the clubhouse community from the aspects o...

Decoding communities in networks.

Science.gov (United States)

Radicchi, Filippo

2018-02-01

According to a recent information-theoretical proposal, the problem of defining and identifying communities in networks can be interpreted as a classical communication task over a noisy channel: memberships of nodes are information bits erased by the channel, edges and nonedges in the network are parity bits introduced by the encoder but degraded through the channel, and a community identification algorithm is a decoder. The interpretation is perfectly equivalent to the one at the basis of well-known statistical inference algorithms for community detection. The only difference in the interpretation is that a noisy channel replaces a stochastic network model. However, the different perspective gives the opportunity to take advantage of the rich set of tools of coding theory to generate novel insights on the problem of community detection. In this paper, we illustrate two main applications of standard coding-theoretical methods to community detection. First, we leverage a state-of-the-art decoding technique to generate a family of quasioptimal community detection algorithms. Second and more important, we show that the Shannon's noisy-channel coding theorem can be invoked to establish a lower bound, here named as decodability bound, for the maximum amount of noise tolerable by an ideal decoder to achieve perfect detection of communities. When computed for well-established synthetic benchmarks, the decodability bound explains accurately the performance achieved by the best community detection algorithms existing on the market, telling us that only little room for their improvement is still potentially left.

Decoding communities in networks

Science.gov (United States)

Radicchi, Filippo

2018-02-01

According to a recent information-theoretical proposal, the problem of defining and identifying communities in networks can be interpreted as a classical communication task over a noisy channel: memberships of nodes are information bits erased by the channel, edges and nonedges in the network are parity bits introduced by the encoder but degraded through the channel, and a community identification algorithm is a decoder. The interpretation is perfectly equivalent to the one at the basis of well-known statistical inference algorithms for community detection. The only difference in the interpretation is that a noisy channel replaces a stochastic network model. However, the different perspective gives the opportunity to take advantage of the rich set of tools of coding theory to generate novel insights on the problem of community detection. In this paper, we illustrate two main applications of standard coding-theoretical methods to community detection. First, we leverage a state-of-the-art decoding technique to generate a family of quasioptimal community detection algorithms. Second and more important, we show that the Shannon's noisy-channel coding theorem can be invoked to establish a lower bound, here named as decodability bound, for the maximum amount of noise tolerable by an ideal decoder to achieve perfect detection of communities. When computed for well-established synthetic benchmarks, the decodability bound explains accurately the performance achieved by the best community detection algorithms existing on the market, telling us that only little room for their improvement is still potentially left.

Selected Hydrologic, Water-Quality, Biological, and Sedimentation Characteristics of Laguna Grande, Fajardo, Puerto Rico, March 2007-February 2009

Science.gov (United States)

Soler-López, Luis R.; Santos, Carlos R.

2010-01-01

Laguna Grande is a 50-hectare lagoon in the municipio of Fajardo, located in the northeasternmost part of Puerto Rico. Hydrologic, water-quality, and biological data were collected in the lagoon between March 2007 and February 2009 to establish baseline conditions and determine the health of Laguna Grande on the basis of preestablished standards. In addition, a core of bottom material was obtained at one site within the lagoon to establish sediment depositional rates. Water-quality properties measured onsite (temperature, pH, dissolved oxygen, specific conductance, and water transparency) varied temporally rather than areally. All physical properties were in compliance with current regulatory standards established for Puerto Rico. Nutrient concentrations were very low and in compliance with current regulatory standards (less than 5.0 and 1.0 milligrams per liter for total nitrogen and total phosphorus, respectively). The average total nitrogen concentration was 0.28 milligram per liter, and the average total phosphorus concentration was 0.02 milligram per liter. Chlorophyll a was the predominant form of photosynthetic pigment in the water. The average chlorophyll-a concentration was 6.2 micrograms per liter. Bottom sediment accumulation rates were determined in sediment cores by modeling the downcore activities of lead-210 and cesium-137. Results indicated a sediment depositional rate of about 0.44 centimeter per year. At this rate of sediment accretion, the lagoon may become a marshland in about 700 to 900 years. About 86 percent of the community primary productivity in Laguna Grande was generated by periphyton, primarily algal mats and seagrasses, and the remaining 14 percent was generated by phytoplankton in the water column. Based on the diel studies the total average net community productivity equaled 5.7 grams of oxygen per cubic meter per day (2.1 grams of carbon per cubic meter per day). Most of this productivity was ascribed to periphyton and macrophytes

Perceptions of the community on the pricing of community mental health services.

Science.gov (United States)

Ogden, J R; Ogden, D T

1992-01-01

In the past few years there has been a decrease in governmental support of Community Mental Health centers. Because of this, there has been some concern, on the part of Community Mental Health professionals, as to the overall impact of this decreased governmental support. Research has been conducted that speculates on how best to handle this mini-crisis. One article suggests moving to an overall marketing approach to help combat this dollar support decline (Day and Ford 1988). Others provide methods for surveying Community Mental Health users (Ludke, Curry & Saywell 1983). William Winston (1988) suggests an overall psychographic segmentation approach to developing market targets. There has also been research detailing promotional methods for expanded marketing coverage (Moldenhauer 1988), however little has been written defining the pricing impact on Community Mental Health services. This study addresses the perceptions of Community Mental Health Center users toward the price variable of the marketing mix.

Handling Pressures of Community Logic

DEFF Research Database (Denmark)

Minbaeva, Dana; Hotho, Jasper; Muratbekova-Touron, Maral

2013-01-01

The paper aims at investigating how in pluralistic societies, such as emerging economies and countries in transition, organizational decision-makers respond to pressures of community logics in non-community settings, such as the work place. We theorize that in non-community settings, social...... relations and interactions with community members can act as social cues that induce and expose individuals to community logics. We subsequently propose that properties of these relations – immediacy and relatedness - will affect individual response strategies towards community logics. We test these ideas...... with an experimental vignette study of the effects of clan and kinship ties on recruitment and selection decisions in Kazakhstan, followed by qualitative interviews....

Can AmeriCorps Build Communities?

Science.gov (United States)

Thomson, Ann Marie; Perry, James L.

1998-01-01

An examination of AmeriCorps in five communities focused on its impact on the capacity of local community-based organizations to achieve community goals. Most partner organizations were unable to build sufficient commitment for self-governance; few programs were designed to encourage collective goals. Getting things done in local communities may…

Generating Community, Generating Justice? The production and circulation of value in community energy initiatives

Directory of Open Access Journals (Sweden)

Taylor Chase Dotson

2016-12-01

Full Text Available In this paper, we explore the potentialities and interconnections between existing and hypothetical community energy systems and the concept of generative justice. New York State’s more recent official energy plan, for instance, includes provisions for community-scale microgrids, and several European nations offer significant financial support to citizens interested in building micro and intermediate-scale renewable energy systems. Such efforts and technologies appear to promise some degree of generative justice, returning much of the value generated by distributed renewable energy back to the community producing it. However, most currently conceived and implemented community energy systems recirculate value in very narrow and limited ways. Building upon an analysis of New York energy policy and on-the-ground cases, we explore community energy’s potential. What kinds of value are being generated by community energy systems and for whom? How could such efforts be more generative of justice across a broad range of values, not just electrons and dollars? Through the attempt to broaden thinking not only about community energy systems but also the concept of generative justice, we connect technological and organizational configurations of community energy systems and the forms of value they have the potential to generate: including, the production of grassroots energy and organizational expertise, the capacity for local and personal autonomy in energy planning and decision-making, and the enhancement of an affective sense and embodied experience of community. Finally, we examine some of the barriers to realizing more generatively just community energy systems. 

Lake Erie Water Level Study. Main Report.

Science.gov (United States)

1981-07-01

indirectly through excessive turbidity, current or depth would impact the higher life forms. Phytoplankton , periphyton and aquatic macrophyte comprise...System. The hydro-electric interest relates to the facilities at the St. Marys River, Welland Canal, Niagara River, St. Lawrence River at Cornwall... relates to three components: water quality, fish, and wildlife. The economic evaluations of regulation plans were also made to determine effects on

Installation Restoration Program. Phase I. Records. Loring AFB, Maine.

Science.gov (United States)

1984-01-01

periphyton from rivers and streams. Publications Dr. Knight has authored several technical papers on ecosystem metabolism, phytoplankton ecology, and...should be made of glacial till and esker (ice contact) deposits along with the calcareous bedrock (Carys Mills Formation) as they relate to the base...material defects of aircraft struc- tures, component parts, and related ground equipment. Wastes generated by the processes involved include PD-680

Phosphorus Transport in Rivers.

Science.gov (United States)

1978-11-01

be attributed to excessive nutrient inputs to the lake. These nutrients sti- mulate the phytoplankton (algae) growth which yields excess growth. The...phosphorus in relation to the restoration of Lake Erie. The various computational techniques presented herein aid in the understanding of total...as caused by the absorption on clay materials and by assimilation by periphyton . Other investigators have found correlations between flow and other

Ecological Effects of Exotic and Native Aquatic Vegetation

Science.gov (United States)

2009-08-01

related problem for fish. Normally, carbon dioxide released during respiration is utilized in photosynthesis or escapes into the atmo- sphere...with algae for nutrients and light (Boyd 1979). Phytoplankton populations are often suppressed in well-established stands of ERDC/EL TR-09-10 8...aquatic plants, and primary productivity is either dependent upon macrophytes and/or periphyton associated with them. Generally, the presence of

Is a community still a community? Reviewing definitions of key terms in community ecology.

Science.gov (United States)

Stroud, James T; Bush, Michael R; Ladd, Mark C; Nowicki, Robert J; Shantz, Andrew A; Sweatman, Jennifer

2015-11-01

Community ecology is an inherently complicated field, confounded by the conflicting use of fundamental terms. Nearly two decades ago, Fauth et al. (1996) demonstrated that imprecise language led to the virtual synonymy of important terms and so attempted to clearly define four keywords in community ecology; "community," "assemblage," "guild," and "ensemble". We revisit Fauth et al.'s conclusion and discuss how the use of these terms has changed over time since their review. An updated analysis of term definition from a selection of popular ecological textbooks suggests that definitions have drifted away from those encountered pre-1996, and slightly disagreed with results from a survey of 100 ecology professionals (comprising of academic professors, nonacademic PhDs, graduate and undergraduate biology students). Results suggest that confusion about these terms is still widespread in ecology. We conclude with clear suggestions for definitions of each term to be adopted hereafter to provide greater cohesion among research groups.

[Community marketing of contraceptives].

Science.gov (United States)

Urrutia, J M

1987-09-01

The 5-year-old community contraceptive distribution program developed by PROFAMILIA, Colombia's private family planning organization, has given excellent results, but several cost-effectiveness comparisons with social marketing programs have suggested that commercial distribution programs are superior. The community contraceptive distribution program has a high content of information and education activities, which produced significant increases in knowledge and use of contraception in the communities covered. It has been a fundamental support for the social marketing program, creating much of the demand for contraceptive products that the social marketing program has filled. The social marketing program has given good results in terms of volume of sales and in cost-effectiveness since 1976, prompting calls for replacement of the community contraceptive distribution program by the social marketing program in those sectors where knowledge and use of contraception have achieved acceptable levels. An experiment in the Department of Santander in 1984 and 1985 gave very favorable results, suggesting that community contraceptive distribution programs should be replaced by social marketing programs in all more developed markets. But economic problems in 1985 and the decision of manufacturers to decrease the profit margin for PROFAMILIA jeopardized the social marketing program. The community distribution program covered about 20% of the market. Reduced profits in the social marketing program threatened its continued expansion, at the same time that potential demand was growing because of increases in the fertile aged population and increased use of contraception. To meet the need, PROFAMILIA combined the community contraceptive distribution and social marketing programs into a new entity to be called community marketing. The strategy of the community marketing program will be to maintain PROFAMILIA's participation in the market and aid the growth of demand for

Creating one planet communities

International Nuclear Information System (INIS)

Wilts, R.

2010-01-01

This presentation discussed low carbon communities that used a variety of sustainable energy technologies to reduce energy consumption and waste. The presentation was given by a company who has adopted a One Planet framework to ensure the development of zero carbon, zero waste, sustainable communities.The Dockside Green project was awarded North America's highest leadership in energy and environmental design (LEED) score. The community includes a waste biomass plant and an on-site wastewater treatment plant. Excess heat produced by the community's greenhouse gas (GHG) neutral biomass district heating system is sold to neighbouring communities. The BedZED project in the United Kingdom uses a high-density format to support a community living and workspace environment that uses rainwater harvesting, passive solar heating, high performance envelopes, and green roofs. The site includes 40 electric car charging stations. A combined heat and power (CHP) biomass plant provides electricity and hot water to all buildings. Neighbourhood-scale sustainable development is expected to have a significant impact on the ecological footprint of North American cities. Carbon neutral projects in Canada were also listed. tabs., figs.

Community benefits or community bribes?:An experimental analysis of strategies for managing community perceptions of bribery surrounding the siting of renewable energy projects

OpenAIRE

Walker, Benjamin J. A.; Russel, Duncan; Kurz, Tim

2017-01-01

The provision of financial incentives to local communities by energy developers has attracted cynicism across many localities, with some suggesting such community benefits are akin to “bribery.” The current study used an experimental design embedded within a community postal survey to explore whether potentially damaging effects of bribery rhetoric upon local support for a wind farm can be overcome through (a) portraying community benefits as a policy requirement (rather than a discretionary ...

Community centrality and social science research.

Science.gov (United States)

Allman, Dan

2015-12-01

Community centrality is a growing requirement of social science. The field's research practices are increasingly expected to conform to prescribed relationships with the people studied. Expectations about community centrality influence scholarly activities. These expectations can pressure social scientists to adhere to models of community involvement that are immediate and that include community-based co-investigators, advisory boards, and liaisons. In this context, disregarding community centrality can be interpreted as failure. This paper considers evolving norms about the centrality of community in social science. It problematises community inclusion and discusses concerns about the impact of community centrality on incremental theory development, academic integrity, freedom of speech, and the value of liberal versus communitarian knowledge. Through the application of a constructivist approach, this paper argues that social science in which community is omitted or on the periphery is not failed science, because not all social science requires a community base to make a genuine and valuable contribution. The utility of community centrality is not necessarily universal across all social science pursuits. The practices of knowing within social science disciplines may be difficult to transfer to a community. These practices of knowing require degrees of specialisation and interest that not all communities may want or have.

Alaska Community Transit

Science.gov (United States)

Grant Information Human Services Funding 5310 5316 (Repealed) 5317 (Repealed) Alaska Mental Health Trust Department of Transportation & Public Facilities/ Alaska Community Transit Search DOT&PF State of Alaska Photo banner DOT&PF> Program Development > Alaska Community Transit Home About Us

Community-Based Care

Science.gov (United States)

... our e-newsletter! Aging & Health A to Z Community-Based Care Basic Facts & Information A variety of healthcare options ... day care centers are either in churches or community centers. Adult day care is commonly used to care for people who ...

Community of Practice

DEFF Research Database (Denmark)

Busch-Jensen, Peter

2012-01-01

A clear and informative description of the theoretical and methodological content and implications of the concept of Community of Practice......A clear and informative description of the theoretical and methodological content and implications of the concept of Community of Practice...

Engaging Institutional Review Boards in Developing a Brief, Community-Responsive Human Subjects Training for Community Partners.

Science.gov (United States)

Calzo, Jerel P; Bogart, Laura M; Francis, Evelyn; Kornetsky, Susan Z; Winkler, Sabune J; Kaberry, Julie

2016-01-01

Engaging community partners as co-investigators in community-based participatory research (CBPR) requires certification in the rules, ethics, and principles governing research. Despite developments in making human research protection trainings more convenient and standardized (eg, self-paced Internet modules), time constraints and the structure of the content (which may favor academic audiences) may hinder the training of community partners. This paper is motivated by a case example in which academic and community partners, and stakeholders of a community-based organization actively engaged the leadership of a pediatric hospital-based institutional review board (IRB) in implementing a brief, community-responsive human subjects training session. A 2-hour, discussion-based human subjects training was developed via collaborations between the IRB and the community and academic partners. Interviews with trainees and facilitators after the training were used to evaluate its acceptability and possible future applications. Local IRBs have the potential to assist community partners in building sufficient knowledge of human subjects research protections to engage in specific projects, thereby expediting the progress of vital research to address community needs. We propose the need for developing truncated human subjects education materials to train and certify community partners, and creating formally organized entities within academic and medical institutions that specialize in community-based research to guide the development and implementation of alternative human subjects training certification opportunities for community partners.

Identification of overlapping communities and their hierarchy by locally calculating community-changing resolution levels

OpenAIRE

Havemann, Frank; Heinz, Michael; Struck, Alexander; Gläser, Jochen

2010-01-01

We propose a new local, deterministic and parameter-free algorithm that detects fuzzy and crisp overlapping communities in a weighted network and simultaneously reveals their hierarchy. Using a local fitness function, the algorithm greedily expands natural communities of seeds until the whole graph is covered. The hierarchy of communities is obtained analytically by calculating resolution levels at which communities grow rather than numerically by testing different resolution levels. This ana...

Community Currency in Korea : How do we envision Community Currency?

NARCIS (Netherlands)

J. Kang (Joonmo); B.E. Hong (Baeg)

2015-01-01

textabstractCommunity currency schemes were first introduced in Korea in 1998. Since then, there have been many efforts to use them but no report or academic research on the topic in Korea. Thus, we conducted a field investigation to identify the scope of community currency schemes in Korea and as

What is microbial community ecology?

Science.gov (United States)

Konopka, Allan

2009-11-01

The activities of complex communities of microbes affect biogeochemical transformations in natural, managed and engineered ecosystems. Meaningfully defining what constitutes a community of interacting microbial populations is not trivial, but is important for rigorous progress in the field. Important elements of research in microbial community ecology include the analysis of functional pathways for nutrient resource and energy flows, mechanistic understanding of interactions between microbial populations and their environment, and the emergent properties of the complex community. Some emergent properties mirror those analyzed by community ecologists who study plants and animals: biological diversity, functional redundancy and system stability. However, because microbes possess mechanisms for the horizontal transfer of genetic information, the metagenome may also be considered as a community property.