Surveying of aquatic insect diversity of Chandrabhaga river,Garhwal Himalayas

Aquatic insect diversity in the Chandrabhaga, an important headwater stream of Garhwal Himalayas, was surveyed for a period of twelve months (October 1999 to September 2000). All the important physico-chemical environmental variables (temperature, water velocity, hydromedian depth, transparency, turbidity, total dissolved solids, pH, alkalinity, dissolved oxygen, free CO₂, nitrates, phosphates, sodium and potassium) of the aquatic ecosystem were measured monthly for one year. Aquatic insects were sampled from three sites (S₁, S₂ & S₃) of the headwater stream Chandrabhaga. Aquatic insects of Chandrabhaga were represented by the members of the orders of Ephemeroptera, Trichoptera, Coleoptera, Diptera, Plecoptera and Odonata. The maximum density of aquatic insects was recorded in the month of March (4,165 ind. m⁻²) and minimum in the month of August (680 ind. m⁻²). The annual contribution of Trichoptera (38%) and Ephemeroptera (32%) was observed to be maximum, while Odonata contributed minimum (2%) to the total aquatic insect density. The present study on the relationship between physico-chemical environmental variables and the density of aquatic insects revealed that the velocity of water, hydromedian depth, turbidity and dissolved oxygen in addition to composition and texture of the bottom substrates have significant impact on benthic aquatic insects’ density and their diversity. The ecological relevance of the measured hydrological attributes was investigated by composing their degree of correlation with insects density and diversity. The diversity index (Shannon–Weiner) of aquatic insects dwelling in the Chandrabhaga river ranged from 2.54 to 3.86. Some of the natural and anthropogenic environmental factors contributing towards the degradation of the watershed of the Chandrabhaga have been identified, and ameliorative measures for the conservation of the aquatic insect diversity have been suggested.     

Biota Connect Aquatic Habitats throughout Freshwater Ecosystem Mosaics

Freshwater ecosystems are linked at various spatial and temporal scales by movements of biota adapted to life in water. We review the literature on movements of aquatic organisms that connect different types of freshwater habitats, focusing on linkages from streams and wetlands to downstream waters. Here, streams, wetlands, rivers, lakes, ponds, and other freshwater habitats are viewed as dynamic freshwater ecosystem mosaics (FEMs) that collectively provide the resources needed to sustain aquatic life. Based on existing evidence, it is clear that biotic linkages throughout FEMs have important consequences for biological integrity and biodiversity. All aquatic organisms move within and among FEM components, but differ in the mode, frequency, distance, and timing of their movements. These movements allow biota to recolonize habitats, avoid inbreeding, escape stressors, locate mates, and acquire resources. Cumulatively, these individual movements connect populations within and among FEMs and contribute to local and regional diversity, resilience to disturbance, and persistence of aquatic species in the face of environmental change. Thus, the biological connections established by movement of biota among streams, wetlands, and downstream waters are critical to the ecological integrity of these systems. Future research will help advance our understanding of the movements that link FEMs and their cumulative effects on downstream waters.     

Phytoremediation of dairy effluent by constructed wetland technology

Constructed wetlands are artificial wastewater treatment systems consisting of shallow ponds or channels which have been planted with aquatic plants and which rely upon natural microbial, biological, physical and chemical process to treat wastewater and are gaining acceptance in the recent years as a viable option for the treatment of industrial effluents and removal of toxic components. In this study, an attempt was made to compare the efficiency of aquatic macrophytes like Typha sp., Eichhornia sp., Salvinia sp., Pistia sp., Azolla sp. and Lemna sp. to treat the effluents from dairy factory, under laboratory conditions in constructed wetlands. The biological oxygen demand and chemical oxygen demand of dairy effluent were reduced up to 65.4–83.07% and 70.4–85.3%, respectively, after treatment with constructed wetland technology.     

Epipellic Algae Profile of the Mixohaline Mangrove Swamp of Qua Iboe River Estuary (Nigeria)

The epipellic algae of Qua Iboe Estuary was studied in late summer (between January and February) of 1999. Physicochemical analysis of the tidal mud flats of the Estuary revealed a mixohaline habitat characterized by its high acidity (pH 4.72±0.02) and rich nutritive salts content. The results of the phytoplankton studies revealed variation in the density of the microalgae within the microalgal Orders. The epipellic algae community was predominated by pinnate diatoms. The mean densities of the phytoplanktons ranged from 102.75 organism/ha, 34.25 organism/ha, 21.25 organism/ha to 1.00 organism/ha of Pennales, Centrales, Zygnematales and Blue-Green algae, respectively. Their densities, however, decreased with increase in sampling distance from the low tide level. At the species level, Actinoptychus undulatus and Tabellaria sp. predominate the microalgae community. The occurrence of the freshwater diatom, A. undulatus, in an otherwise harsh salty epipellic habitat confirms the adaptive potential of some freshwater phytoplankton to marine ecosystem. Other phytoplankter present in the epipellic habitat of the estuary were Amphora ovalis, Campylodis cibrosus, Cymbella lanceolata, Navicular radiosa, N. rhynocephala, Pleurosignma sp., Pinnularia viridis, Stephanodiscus sp., Closterium sp., Oscillatoria nigroviridis and Nodularia spumigena.     

Combining Flow Cytometry and Real-Time PCR Methodology to Demonstrate Consumption by Prymnesium parvum1

Bowers, Holly A., Andreas Brutemark, Wanderson F. Carvalho, and Edna Granéli, 2010. Combining Flow Cytometry and Real-Time PCR Methodology to Demonstrate Consumption by Prymnesium parvum. Journal of the American Water Resources Association (JAWRA) 46(1):133-143. DOI: 10.1111/j.1752-1688.2009.00397.x Abstract: Harmful algal bloom species can persist in the environment, impacting aquatic life and human health. One of the mechanisms by which some harmful algal bloom species are able to persist is by consumption of organic particles. Methods to demonstrate and measure consumption can yield insight into how populations thrive. Here, we combine flow cytometry and real-time PCR to demonstrate consumption of a cryptophyte species (Rhodomonas sp.) by a toxic mixotrophic haptophyte (Prymnesium parvum). Using flow cytometry, the feeding frequency of a population of P. parvum cells was calculated using the phycoerythrin (PE) fluorescence signal from Rhodomonas sp. and the fluorescence of an acidotropic probe labeling the food vacuoles. Feeding frequency increased in the beginning of the experiment and then began to decline, reaching a maximum of 47.5% of the whole P. parvum population after 212 min. The maximum number of consumed Rhodomonas sp. cells was 0.8 per P. parvum cell, and occurred after 114 min corresponding to an ingestion rate of 0.4 Rhodomonas sp. cells/P. parvum/h. Cells from the feeding P. parvum population were sorted, washed, and subjected to a real-time PCR assay targeting the cryptophyte 18S locus. There was a correlation between cycle threshold (Ct) values and number of consumed prey cells calculated by fluorescence. Overall, this study shows that flow cytometric analysis, of the acidotropic probe and prey pigments, is an efficient and rapid tool in enumerating food vacuoles and the number of prey cells consumed. Furthermore, we suggest that real-time PCR can be applied to cells sorted by flow cytometry, thus allowing for the detection and potential quantification of the targeted prey cells.     

Effects of Land Use and Climate Change on Stream Temperature II: Threshold Exceedance Duration Projections for Freshwater Mussels

We developed a stochastic hourly stream temperature model (SHSTM) to estimate probability of exceeding given threshold temperature (T) for specified durations (24 and 96 h) to assess potential impacts on freshwater mussels in the upper Tar River, North Carolina. Simulated daily mean stream T from climate change (CC) and land‐use (LU) change simulations for 2021‐2030 and 2051‐2060 were used as input to the SHSTM. Stream T observations in 2010 revealed only two sites with T above 30°C for >24 h and Ts were never >31°C for more than 24 h at any site. The SHSTM suggests that the probability, P, that T will exceed 32°C for at least 96 h in a given year increased from P = 0, in the 20th Century, to P = 0.05 in 2021‐2030 and to P = 0.14 in 2051‐2060. The SHSTM indicated that CC had greater effects on P for 24 and 96 h durations than LU change. Increased P occurred primarily in higher order stream segments in the downstream reaches of the basin. The SHSTM indicated that hourly stream T responded to LU change on the daily scale and did not affect stream T for durations >24 h. The SHSTM indicated that known thermal thresholds for freshwater mussels could be exceeded within the next 50 years in many parts of the upper Tar River basin in North Carolina, which could have negative consequences on the recruitment of freshwater mussels.     

COAL ASH BASIN EFFECTS (PARTICULATES,METALS, ACIDIC pH) UPON AQUATIC BIOTA: AN EIGHT-YEAR EVALUATION1

ABSTRACT Coal ash effluent effects including particulates, acidic pH excursions, elemental concentrations and bioconcentration in selected organisms have been studied as changes in water quality and densities of benthic macroinvertebrate and mosquitofish (Gambusia affinis) populations in a swamp drainage system over an eight-year period. Three changes in the ash basin settling system were made between mid- 1973 and January 1982. Initial density of the aquatic biota was altered severely by heavy ash siltation, followed by acidic pH excursions and perhaps overall by elemental concentrations and bioaccumulation. Heavy ash siltation, followed by acidic Ph excursions (mean of 5.5, extreme of 3.5) after the addition of fly ash to the original settling basin system, had the most profound effect on biota. Dipterans (chironomids) and some odonates (Plathemis lydia and Libellula spp.) were resistant to heavy ash siltation, while mosquitofish, which showed no discernible responses to ash siltation, were absent at acidic pH, along with the few previously surviving invertebrate populations. Elemental concentrations of arsenic, cadmium, chromium, copper, selenium, and zinc did not appear to limit aquatic flora and fauna on a short-term, acute basis. Long, chronic elemental exposures may have been instrumental in retarding the recovery of all forms of aquatic life in the receiving system. Elemental concentrations (except for arsenic and selenium) in the receiving system were generally one to two orders of magnitude higher than the Water Quality Criteria set by the U.S. Environmental Protection Agency (1980) for protection of aquatic life for the minimum and 24-hour mean values. From collective elemental exposures in the receiving system, bioconcentration factors in macrophytes, invertebrates and fish were generally lower than those reported in the literature for laboratory, single elemental concentrations. By 1978, when the new settling basin systems were operating effectively, invertebrate populations were largely recovered, and mosquitofish populations recovered within one year afterward.     

Ecoregions in the Southern Balkans: Should Their Boundaries Be Revised?

Ecoregion delineations have gained increased attention in Europe, especially following the Water Framework Directive 2000/60/EC (WFD), which provides the European Union’s first policy-relevant ecoregion map. However, the WFD’s ecoregions were created through a minor adaptation of Illies’ (Limnofauna Europaea. Gustav Fisher Verlag, Stuttgart, 1967/1978) freshwater zoogeographic regions, and the map’s specific boundaries have not been widely evaluated with respect to the WFD’s uses or their biogeographic accuracy. We examined the WFD ecoregion boundaries in Greece and its neighboring Balkan states by comparing them with the most prominent freshwater biogeographic boundaries as shown by riverine freshwater fish assemblages. Classification and ordination analyses of 23 river basin fish assemblages helped delineate natural faunal break boundaries in freshwater species assemblage distributions depicting major biogeographic barriers to aquatic biota dispersal. However, these biogeographic boundaries differ from those delineated in the WFD map, suggesting boundary errors and inconsistencies in the delineation method of the WFD ecoregions. We reviewed specific boundary disagreements and produced a map showing the region’s most prominent freshwater biogeographic boundaries by charting them on watershed borders among the four biotically dissimilar river basin groups in the southern Balkans. This regional evaluation reveals both a need to reconcile disparate approaches to ecoregion mapping and to promote the development of a new policy-relevant inland waters ecoregion framework that would support broad-scale water management and aquatic conservation.     

Effects of Turbidity,Sediment, and Polyacrylamide on Native Freshwater Mussels

Turbidity is a ubiquitous pollutant adversely affecting water quality and aquatic life in waterways globally. Anionic polyacrylamide (PAM) is widely used as an effective chemical flocculent to reduce suspended sediment (SS) and turbidity. However, no information exists on the toxicity of PAM‐flocculated sediments to imperiled, but ecologically important, freshwater mussels (Unionidae). Thus, we conducted acute (96 h) and chronic (24 day) laboratory tests with juvenile fatmucket (Lampsilis siliquoidea) and three exposure conditions (nonflocculated settled sediment, SS, and PAM‐flocculated settled sediment) over a range of turbidity levels (50, 250, 1,250, and 3,500 nephelometric turbidity units). Survival and sublethal endpoints of protein oxidation, adenosine triphosphate (ATP) production, and protein concentration were used as measures of toxicity. We found no effect of turbidity levels or exposure condition on mussel survival in acute or chronic tests. However, we found significant reductions in protein concentration, ATP production, and oxidized proteins in mussels acutely exposed to the SS condition, which required water movement to maintain sediment in suspension, indicating responses that are symptoms of physiological stress. Our results suggest anionic PAM applied to reduce SS may minimize adverse effects of short‐term turbidity exposure on juvenile freshwater mussels without eliciting additional lethal or sublethal toxicity.     

Integrating Nonindigenous Aquatic Plant Control with Protection of Snail Kite Nests in Florida

The endangered snail kite (Rostrhamus sociabilis) feeds primarily on the freshwater apple snail (Pomacea paludosa) in Florida. The nonindigenous, floating water hyacinth (Eichhornia crassipes) and water lettuce (Pistia stratiotes) impede kites from finding snails. Effective control of these aquatic plants in the littoral zone of central and south Florida lakes benefits kites by maintaining open foraging habitat. However, incidental herbicide spraying of nesting substrates result in nest collapse when kites breed in nonwoody, emergent plants [cattail (Typha spp.) and giant bulrush (Scirpus validus)] in the outer littoral zone during lower lake levels. Many endangered species recovery plans and their implementation have experienced problems due to inaction and/or noncooperation by various governmental agencies and their personnel. Herein, we describe the development and implementation of a buffer zone strategy to prevent secondary impacts from an aquatic plant control program to snail kites nesting on lakes in central and south Florida. A strategy was jointly developed by personnel of five state and federal agencies to control herbicide application near kite nesting areas during the normal breeding season. Although requiring various modifications during its implementation, this cooperative effort successfully integrated aquatic plant control objectives with snail kite conservation on Lake Okeechobee during 1988. The program was expanded the following year to lakes Kissimmee and Tohopekaliga. Since the implementation of the snail kite impact preclusion program, no nest loss was attributed to incidental herbicide applications on lakes Okeechobee, Kissimmee, and Tohopekaliga.     

Forest Insect Pest Management and Forest Management in China: An Overview

According to the Seventh National Forest Inventory (2004–2008), China’s forests cover an area of 195.45 million ha, or 20.36% of the total land area. China has the most rapidly increasing forest resources in the world. However, China is also a country with serious forest pest problems. There are more than 8,000 species of potential forest pests in China, including insects, plant diseases, rodents and lagomorphs, and hazardous plants. Among them, 300 species are considered as economically or ecologically important, and half of these are serious pests, including 86 species of insects. Forest management and utilization have a considerable influence on the stability and sustainability of forest ecosystems. At the national level, forestry policies always play a major role in forest resource management and forest health protection. In this paper, we present a comprehensive overview of both achievements and challenges in forest management and insect pest control in China. First, we summarize the current status of forest resources and their pests in China. Second, we address the theories, policies, practices and major national actions on forestry and forest insect pest management, including the Engineering Pest Management of China, the National Key Forestry Programs, the Classified Forest Management system, and the Collective Forest Tenure Reform. We analyze and discuss three representative plantations—Eucalyptus, poplar and Masson pine plantations—with respect to their insect diversity, pest problems and pest management measures.     

Petroleum hydrocarbons and limiting nutrients in <Emphasis Type="Italic">Macura reptantia</Emphasis>, <Emphasis Type="Italic">Procambarus clarkii</Emphasis> and benthic sediment from Qua Iboe Estuary,Nigeria

The levels of total petroleum hydrocarbons in two commonly consumed benthopelagic shellfishes, Macura reptantia and Procambarus clarkii, harvested from benthic sediment of Qua Iboe Estuary were determined using a gas chromatography with flame-ionization detector. Seventy-two (72) samples each of benthic sediment and the shellfishes were collected monthly between June 2003 and February 2004 covering the peak periods of the wet and dry seasons. Concentrations of hydrocarbons were highly variable and ranged between 5.00 and 232.00 μg/g dry weight of benthic sediment, 3.05 and 11.30 μg/g dry weight of M. reptantia, 1.62 and 9.00 μg/g dry weight of P. clarkii. Pearson’s correlation analysis of total hydrocarbon concentrations in subtidal sediments with levels in the fauna species yielded positive significant (P < 0.05) correlations in M. reptantia (r = 0.737) and P. clarkii (r = 0.924). This is indicative of a long term and chronic accumulation of hydrocarbons in the estuarine ecosystem, reflecting the potential for exposure of the resident biota and the risk to human health.     

Influences of Spatial Scale and Soil Permeability on Relationships Between Land Cover and Baseflow Stream Nutrient Concentrations

The Little Miami River (LMR) basin, dominated by agriculture, contains two geologically-distinct regions; a glaciated northern till plain with soils three times more permeable than a southern, pre-Wisconsinan drift plain. The influences of two landscape measures, percent row crop cover (%RCC, computed at three spatial scales), and soil permeability (PERM), on baseflow nutrient concentrations were modeled using linear regressions. Quarterly water samples collected for four years were analyzed for nitrate-N (NN), Kjeldahl-N (KN), total-N (TN), and total-P (TP). In till plain streams (n = 17), NN concentrations were 8.5-times greater than drift plain streams (n = 18), but KN and TP were 20–40% lower at comparable %RCC. These differences resulted in TN/TP molar ratios >80 in till plain streams, but <6 in drift plain streams. For till plain steams regression models based on %RCC accounted for 79% of the variance in NN concentrations but only 27% in drift plain streams. However, regressions on %RCC accounted for 68–75% of the KN and TP concentration variance in the drift plain streams but essentially none in the till plain. Catchment PERM influenced the regional NN/KN ratios which were 10-fold higher in the drift plain streams. For both till and drift streams the catchment scale %RCC gave the best predictions of NN, a water soluble anion, but the smaller spatial scales produced better models for insoluble nutrient species (e.g., KN and TP). Published literature on Ohio streams indicates that these inter-regional differences in nutrient ratios have potential implications for aquatic biota in the receiving streams.     

Are leaves that fall from imidacloprid-treated maple trees to control Asian longhorned beetles toxic to non-target decomposer organisms?

The systemic insecticide imidacloprid may be applied to deciduous trees for control of the Asian longhorned beetle, an invasive wood-boring insect. Senescent leaves falling from systemically treated trees contain imidacloprid concentrations that could pose a risk to natural decomposer organisms. We examined the effects of foliar imidacloprid concentrations on decomposer organisms by adding leaves from imidacloprid-treated sugar maple trees to aquatic and terrestrial microcosms under controlled laboratory conditions. Imidacloprid in maple leaves at realistic field concentrations (3-11 mg kg(-1)) did not affect survival of aquatic leaf-shredding insects or litter-dwelling earthworms. However, adverse sublethal effects at these concentrations were detected. Feeding rates by aquatic insects and earthworms were reduced, leaf decomposition (mass loss) was decreased, measurable weight losses occurred among earthworms, and aquatic and terrestrial microbial decomposition activity was significantly inhibited. Results of this study suggest that sugar maple trees systemically treated with imidacloprid to control Asian longhorned beetles may yield senescent leaves with residue levels sufficient to reduce natural decomposition processes in aquatic and terrestrial environments through adverse effects on non-target decomposer organisms.     

Understanding Stream Geomorphic State in Relation to Ecological Integrity: Evidence Using Habitat Assessments and Macroinvertebrates

Scientists have long assumed that the physical structure and condition of stream and river channels have pervasive effects on biological communities and processes, but specific tests are few. To investigate the influence of the stream-reach geomorphic state on in-stream habitat and aquatic macroinvertebrate communities, we compared measures of habitat conditions and macroinvertebrate community composition between stable and unstable stream reaches in a paired-study design. We also explored potential associations between these ecological measures and individual geomorphic characteristics and channel adjustment processes (degradation, aggradation, overwidening, and change in planform). We found that habitat quality and heterogeneity were closely tied to stream stability, with geomorphically stable reaches supporting better habitat than unstable reaches. Geomorphic and habitat assessment scores were highly correlated (r = 0.624, P < 0.006, n = 18). Stable reaches did not support significantly greater macroinvertebrate densities than unstable reaches (t = −0.415, P > 0.689, df = 8). However, the percent of the macroinvertebrate community in the Ephemeroptera, Plecoptera, and Trichoptera (EPT) taxa was significantly correlated with the overall habitat assessment scores as well as with individual measures of geomorphic condition and habitat quality. While there is a clear need for more work in classifying and quantifying the responses of aquatic and aquatic-dependent biota to various geomorphic states and processes, this study provides solid preliminary evidence that macroinvertebrate communities are affected by the geomorphic condition of the stream reaches they inhabit and that geomorphic assessment approaches can be used as a tool for evaluating ecological integrity.     

Arctic Lake Physical Processes and Regimes with Implications for Winter Water Availability and Management in the National Petroleum Reserve Alaska

Lakes are dominant landforms in the National Petroleum Reserve Alaska (NPRA) as well as important social and ecological resources. Of recent importance is the management of these freshwater ecosystems because lakes deeper than maximum ice thickness provide an important and often sole source of liquid water for aquatic biota, villages, and industry during winter. To better understand seasonal and annual hydrodynamics in the context of lake morphometry, we analyzed lakes in two adjacent areas where winter water use is expected to increase in the near future because of industrial expansion. Landsat Thematic Mapper and Enhanced Thematic Mapper Plus imagery acquired between 1985 and 2007 were analyzed and compared with climate data to understand interannual variability. Measured changes in lake area extent varied by 0.6% and were significantly correlated to total precipitation in the preceding 12 months (p < 0.05). Using this relation, the modeled lake area extent from 1985 to 2007 showed no long-term trends. In addition, high-resolution aerial photography, bathymetric surveys, water-level monitoring, and lake-ice thickness measurements and growth models were used to better understand seasonal hydrodynamics, surface area-to-volume relations, winter water availability, and more permanent changes related to geomorphic change. Together, these results describe how lakes vary seasonally and annually in two critical areas of the NPRA and provide simple models to help better predict variation in lake-water supply. Our findings suggest that both overestimation and underestimation of actual available winter water volume may occur regularly, and this understanding may help better inform management strategies as future resource use expands in the NPRA.     

TRANSPORT OF SEDIMENT-BOUND ORGANOCHLORINE PESTICIDES TO THE SAN JOAQUIN RWER,CALIFORNIA1

ABSTRACT: Suspended sediment samples were collected in west-side tributaries and the main stem of the San Joaquin River, California, in June 1994 during the irrigation season and in January 1995 during a winter storm. These samples were analyzed for 15 organochiorine pesticides to determine their occurrence and their concentrations on suspended sediment and to compare transport during the irrigation season (April to September) to transport during winter storm runoff (October to March). Ten organochiorine pesticides were detected during the winter storm runoff; seven during the irrigation season. The most frequently detected organochlorine pesticides during both sampling periods were p,p'-DDE, p,p'-DDT, p,p'-DDD, dieldrin, toxaphene, and chiordane. Dissolved samples were analyzed for three organochiorine pesticides during the irrigation season and for 15 during the winter storm. Most calculated total concentrations of p,p-DDT, chlordane, dieldrin, and toxaphene exceeded chronic criteria for the protection of freshwater aquatic life. At eight sites in common between sampling periods, suspended sediment concentrations and streamfiow were greater during the winter storm runoff - median concentration of 3,590 mg/L versus 489 mg(L and median streamfiow of 162 ft³/s versus 11 ft³/s. Median concentrations of total DDT (sum of p,p'-DDD, p,p-DDE, and p,p'-DDT), chlordane, dieldrin, and toxaphene on suspended sediment were slightly greater during the irrigation season, but instantaneous loads of organochlorine pesticides at the time of sampling were substantially greater during the winter storm. Estimated loads for the entire irrigation season exceeded estimated loads for the January 1995 storm by about 2 to 4 times for suspended transport and about 3 to 11 times for total transport. However, because the mean annual winter runoff is about 2 to 4 times greater than the runoff during the January 1995 storm, mean winter transport may be similar to irrigation season transport. This conclusion is tentative primarily because of insufficient information on long-term seasonal variations in suspended sediment and organochlorine concentrations. Nevertheless, runoff from infrequent winter storms will continue to deliver a significant load of sediment-bound organochiorine pesticides to the San Joaquin River even if irrigation-induced sediment transport is reduced. As a result, concentrations of organochlorine pesticides in San Joaquin River biota will continue to be relatively high compared to other regions of the United States.     

TROPHIC LEVEL ACCUMULATION OF HEAVY METALS IN A COAL ASH BASIN DRAINAGE SYSTEM1

ABSTRACT: The uptake of ten chemical elements was measured in water, sediment, fly ash, and the major biotic components of an ash basin drainage system. The biota tested represent several trophic levels observed in the settling basin and receiving swamp of the system. Concentrations were measured by neutron activation (NAA) in the major biotic groups including aquatic bacteria, algae, macrophytes, midges, dragonflies, crayfish, tadpoles, and fish. Only three elements (Cu, Zn, Cd) were more highly concentrated in water from a nearby unpolluted stream than in the fly ash effluent. Sediment concentrations of all elements were highest in the ash drainage system with Al and Fe being consistently highest. Among the biota, Hydrodictyon sp. and Lemna perpusilla had the highest concentrations of Al and Fe while other macrophytes were the major accumulators of Mn and Ba. Invertebrates generally concentrated high amounts of Cu and Zn although Cd and Hg were accumulated most by crayfish. Selenium was selectively concentrated by bacteria, crayfish (Procambarus sp.) and mosquitofish (Gambusia afflnis). Consequences of elemental concentrations in sediment and in specific trophic level groups are discussed.     

Streamside Forest Buffer Width Needed to Protect Stream Water Quality,Habitat, and Organisms: A Literature Review

This literature review addresses how wide a streamside forest buffer needs to be to protect water quality, habitat, and biota for small streams (≤~100 km² or ~5th order watershed) with a focus on eight functions: (1) subsurface nitrate removal varied inversely with subsurface water flux and for sites with water flux >50 l/m/day (~40% avg base flow to Chesapeake Bay) median removal efficiency was 55% (26‐64%) for buffers <40 m wide and 89% (27‐99%) for buffers >40 m wide; (2) sediment trapping was ~65 and ~85% for a 10‐ and 30‐m buffer, respectively, based on streamside field or experimentally loaded sites; (3) stream channel width was significantly wider when bordered by ~25‐m buffer (relative to no forest) with no additional widening for buffers ≥25 m; (4) channel meandering and bank erosion were lower in forest but more studies are needed to determine the effect of buffer width; (5) temperature remained within 2°C of levels in a fully forested watershed with a buffer ≥20 m but full protection against thermal change requires buffers ≥30 m; (6) large woody debris (LWD) has been poorly studied but we infer a buffer width equal to the height of mature streamside trees (~30 m) can provide natural input levels; (7, 8) macroinvertebrate and fish communities, and their instream habitat, remain near a natural or semi‐natural state when buffered by ≥30 m of forest. Overall, buffers ≥30 m wide are needed to protect the physical, chemical, and biological integrity of small streams.     

Differences in bioregional classifications among four aquatic biotic groups: Implications for conservation reserve design and monitoring programs

Bioregional classifications are used extensively for conservation management and monitoring programs. This study used generalised dissimilarity modelling (GDM) to test the ability of different regional classifications of four groups of aquatic biota to be used as surrogates for each other. Classifications were derived for aquatic macrophytes, macroinvertebrates, freshwater fish and frogs using community-level modelling, or GDM, which relates the biotic assemblage structure with environmental variables. Six regions were defined for each biotic group for the State of New South Wales. Regional classifications differed markedly between the different biotic groups because the environmental drivers that were related to species turnover throughout the region differed among groups. Altitude and rainfall were the strongest drivers of species turnover among the groups. Results suggest that physiographic variables should be incorporated in reserve design and monitoring programs to explicitly address differences in classifications between similar biotic groups.