Drift of invertebrates in an intermittent stream draining marshy terrain of west-central Alberta

1972 ◽  
Vol 50 (7) ◽  
pp. 985-991 ◽  
Author(s):  
Hugh F. Clifford
Keyword(s):  
Pore Size ◽  
Detrimental Effect ◽  
Main Stream ◽  
Immature Stages ◽  
Intermittent Stream ◽  
Chironomid Larvae ◽  
West Central ◽  
Benthic Animals

Seven 24-h drift samples were taken with a plankton net (pore size: 76 μ) over a 1-year period from an intermittent stream that drains marshy, muskeg-type terrain of west-central Alberta, Canada. The drift was mainly composed of planktonic and benthic animals originating in the marsh. The only abundant lotic taxon in the drift was simuliid larvae. Rotifers and cyclopoid nauplii were numerically the most important taxa. Drift densities for the fauna as a whole tended to decrease as the ice-free season progressed, but there was no consistent correlation between drift densities and flow. However total daily drift across a point varied directly with flow. All the abundant taxa drifted more during the day than at night, and nematodes, harpacticoids, simuliid larvae, chironomid larvae, chydorids, and rotifers were found in significantly (P < 0.05) greater numbers in the daytime drift. Drift rates of taxa caught in the plankton net were compared with drift rates of the same taxa caught in a 320-μ drift net. Rotifers, entomostracans (especially the immature stages), and even small simuliid and chironomid larvae would have been seriously underestimated using only the 320-μ net. The marshy areas via drift through the intermittent tributaries contribute a very large number of small organisms to the main stream. Draining the wetlands might have a pronounced detrimental effect on the main stream's ecosystem.

Accumulation of Mercury by Plankton and Benthic Invertebrates in Riverine Lakes of Northern Manitoba (Canada): Importance of Regionally and Seasonally Varying Environmental Factors

1988 ◽  
Vol 45 (10) ◽  
pp. 1744-1757 ◽  
Author(s):  
Togwell A. Jackson
Keyword(s):  
Organic Matter ◽  
Environmental Factors ◽  
Benthic Invertebrates ◽  
Spring Flood ◽  
Chironomid Larvae ◽  
Decomposition Of Organic Matter ◽  
Preferential Uptake ◽  
Predominant Effect ◽  
Benthic Animals ◽  
Hg Accumulation

Mercury (Hg) concentrations in plankton and benthic invertebrates from riverine lakes of northern Manitoba were generally found to be unrelated, or inversely related, to inorganic and methyl mercury levels and Hg methylation rates in their habitats but were strongly dependent on environmental factors. The relationships suggest that the uptake of Hg by these organisms was controlled largely by suspended and sedimentary Hg-binding substances such as FeOOH, MnOOH, organic matter, sulfides, and clay. The sole exception was midsummer phytoplankton, whose Hg content was a function of Hg levels in local sediments, probably because interference by suspended detritus was minimal; during the spring flood, such interference had a predominant effect. Aeration of lake water by fluvial currents probably enhances the availability of Hg to plankton by promoting decomposition of organic matter and sulfides but decreases the availability of Hg to some benthic animals by causing MnOOH precipitation. FeOOH apparently limits Hg uptake by chironomid larvae but MnOOH limits Hg uptake by oligochaetes, nematodes, and pelecypods, suggesting preferential uptake of certain forms of Hg by particular biological and mineral species. Decreases in temperature may also retard Hg uptake by benthos. Biodilution has no significant effect on Hg accumulation by benthos or plankton.

THE DIURNAL ACTIVITY OF THE LARGER INVERTEBRATES AT THE SURFACE OF LAC LA RONGE, SASKATCHEWAN

1959 ◽  
Vol 37 (6) ◽  
pp. 945-956 ◽  
Author(s):  
J. H. Mundie
Keyword(s):  
Hyalella Azteca ◽  
Diurnal Activity ◽  
Large Lake ◽  
Mysis Relicta ◽  
Chironomid Larvae ◽  
The Hours ◽  
Chironomid Midges ◽  
Different Depths ◽  
Benthic Animals

Horizontal hauls were made with a pair of large plankton nets at the surface of a large lake to determine the 24-hour emergence cycle of chironomid midges rising from different depths and to investigate the occurrence of the larger invertebrates at the surface. Chironomid pupae ascend mainly in the hours of darkness and emergence may be immediate, as in Psilotanypus rufovittatus, or delayed for several hours, as in Procladius choreus. A migration to the surface at night is demonstrated for Mysis relicta and the amphipods Pontoporeia affinis and Hyalella azteca. Chironomid larvae and a variety of other invertebrates also occur at the surface. The findings show that many benthic animals are less static in their distribution than is commonly accepted.

Host availability affects the interaction between pupal parasitoidCoptera haywardi(Hymenoptera: Diiapridae) and larval–pupal parasitoidDiachasmimorpha longicaudata(Hymenoptera: Braconidae)

2018 ◽  
Vol 109 (1) ◽  
pp. 15-23 ◽  
Author(s):  
P. Montoya ◽  
C. Gálvez ◽  
F. Díaz-Fleischer
Keyword(s):  
Biological Control ◽  
Detrimental Effect ◽  
Developmental Stages ◽  
Anastrepha Ludens ◽  
Immature Stages ◽  
Pupal Parasitoid ◽  
Augmentative Biological Control ◽  
Diachasmimorpha Longicaudata ◽  
Control Programmes ◽  
Multiple Species

AbstractThe use of multiple species in biological control programmes is controversial when interactions among them are not fully understood. We determined the response of the pupal parasitoidCoptera haywardi(Oglobin) to different availability ofAnastrepha ludens(Loew) pupae previously parasitized or not by larval–pupalDiachasmimorpha longicaudata(Ashmead). The two types of pupae were exposed at different ages and proportions to different numbers ofC. haywardifemales for 48 h. The performance ofC. haywardiadults emerging from parasitized and unparasitized pupae was measured.Coptera haywardiprefers to attack unparasitizedA. ludenspupae rather than pupae parasitized byD. longicaudata. However, when the availability of unparasitized pupae was low or the number of foraging females was high,C. haywardicompeted against early immature stages of theD. longicaudata, or hyperparasitized, feeding directly on the advanced-immature developmental stages of the early acting species. Adults ofC. haywardiemerging as hyperparasitoids were no different in size, fecundity and longevity from those emerging as primary parasitoids. Our data suggest that simultaneous use of these species in augmentative biological control projects may be feasible but should be carefully planned in order to avoid any detrimental effect of its interaction.

scholarly journals Results of zoobentos research in river Sotka, PINEZHSKY STATE RESERVE (Arkhangelsk region, Russia)

2021 ◽  
pp. 16-30
Author(s):  
Сергей Николаевич Артемьев ◽  
Александр Павлович Новоселов ◽  
Николай Владимирович Климовский ◽  
Геннадий Александрович Дворянкин ◽  
Олег Станиславович Дурныкин
Keyword(s):  
Water Quality ◽  
Taxonomic Diversity ◽  
Bivalve Mollusks ◽  
Chironomid Larvae ◽  
Spatial Aspect ◽  
Species Similarity ◽  
Bristle Worms ◽  
Quantitative Indicators ◽  
Benthic Animals ◽  
Benthic Sampling

В статье рассмотрен качественный состав (видовое и таксономическое разнообразие) и количественные показатели (встречаемость, численность и биомасса) зообентоса р. Сотка в пространственном аспекте. Выявлены участки реки с минимальной и максимальной численностью и биомассой. Определены доминирующие группы донных животных по численности (личинки хирономид и малощетинковые черви) и биомассе (двукрылые, олигохеты и двустворчатые моллюски). На основе кластерного анализа (по видовому сходству) станции отбора бентосных проб объединены в 2 группы. Качество вод оценено как условно чистое - слабо загрязненное. Проведенные исследования зообентоса в уникальной реке на территории заповедника Пинежский будут использованы при ведении комплексного мониторинга качества вод и биотической части ее экосистемы (фито- и зоопланктон, зообентос, ихтиофауна), включая и приточную систему. The article considers the qualitative composition (species and taxonomic diversity) and quantitative indicators (occurrence, number and biomass) of zoobenthos of river Sotka in the spatial aspect. The sections of the river with the minimum and maximum abundance and biomass were identified. The dominant groups of benthic animals were determined by their numbers (chironomid larvae and small-bristle worms) and biomass (dipterans, oligochaetes and bivalve mollusks). Comparison of quantitative indicators in the annual aspect revealed a significant increase in biomass and relative stability of abundance over a 20-year period at the Filippovskoye site, as well as a decrease in numbers and biomass at the Moiseev Nos site. Based on cluster analysis (by species similarity), benthic sampling stations are combined into 2 groups. Water quality is assessed as conditionally pure, slightly polluted. Studies of zoobenthos in a unique river on the territory of the Pinezhsky reserve will be used to conduct a comprehensive monitoring of water quality and the biotic part of its ecosystem (phyto- and zooplankton, zoobenthos, ichthyofauna), including the inflow system.

Dynamique spatio-temporelle des déplacements de macroinvertébrés dans une grande rivière

1988 ◽  
Vol 66 (2) ◽  
pp. 352-363 ◽  
Author(s):  
Bernard Cellot ◽  
Michel Bournaud
Keyword(s):  
Flow Rate ◽  
Temporal Variations ◽  
Artificial Substrates ◽  
Main Stream ◽  
Asellus Aquaticus ◽  
Gammarus Fossarum ◽  
Chironomid Larvae ◽  
Upstream Reservoir ◽  
Spatio Temporal ◽  
Large Flow

The movements of macroinvertebrates in the Rhône River were studied by using suspended artificial substrates that were immersed for 7 days at three depths near a bank and at the centre of the channel at Jons (27 km upstream of Lyon, France). Sampling was carried out monthly on an annual cycle, from December 1978 to March 1980. The 93 taxa found were distributed as follows: chironomid larvae (Diptera), 34.4%; Hydropsyche spp. (Trichoptera), 24.9%; Oligochaeta, 15.7%; Gammarus fossarum and (or) G. pulex (Crustacea), 15.0%; others, 10.0%. Correspondence analysis revealed and summarized the hierarchy of the spatio-temporal variations in fauna. The first level of variation is seasonal and shows contrasts between some summer species (e.g., Ephemerella ignita, Leuctra fusca) and the pool of organisms that subsist during winter. The second level of variation is due to seasonal hydrological conditions. The large flow rate during winter and at the beginning of the summer instigates the drift of rheolithophilous (e.g., Psychomyia pusilla) or limnophilous (Asellus aquaticus) taxa, which results in a more intense spatial homogenization of the fauna. The first increase in flow rate after a slower regime, although minor, has a "washing out" effect on the backwaters connected with the main stream (parapotamic area). On the other hand, the slower flow rate at the end of summer is favourable to some extent for some lentic taxa (Planaria), particularly near the banks. A third level of variation, less important, concerns transverse movements (between bank and channel) and the effects of emptying and cleaning the upstream reservoir.

Transfer Technique for Electron Microscopy of Membrance Filter Samples

1974 ◽  
Vol 32 ◽  
pp. 554-555
Author(s):  
Lawrence W. Ortiz ◽  
Bonnie L. Isom
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Pore Size ◽  
Membrane Filters ◽  
Size Dependent

A procedure is described for the quantitative transfer of fibers and particulates collected on membrane filters to electron microscope (EM) grids. Various Millipore MF filters (Millipore AA, HA, GS, and VM; 0.8, 0.45, 0.22 and 0.05 μm mean pore size) have been used with success. Observed particle losses have not been size dependent and have not exceeded 10%. With fibers (glass or asbestos) as the collected media this observed loss is approximately 3%.

The microstructure of functionalized poLyacrylonitrile beads for bioseparations

1990 ◽  
Vol 48 (4) ◽  
pp. 1094-1095
Author(s):  
Eduardo A. Kamenetzky ◽  
David A. Ley
Keyword(s):  
Aqueous Solution ◽  
Affinity Chromatography ◽  
Pore Size Distribution ◽  
Pore Size ◽  
Surface Coverage ◽  
Vacuum Impregnation ◽  
Thin Sections ◽  
Selective Staining ◽  
Low Viscosity ◽  
Diamond Knife

The microstructure of polyacrylonitrile (PAN) beads for affinity chromatography bioseparations was studied by TEM of stained ultramicrotomed thin-sections. Microstructural aspects such as overall pore size distribution, the distribution of pores within the beads, and surface coverage of functionalized beads affect performance properties. Stereological methods are used to quantify the internal structure of these chromatographic supports. Details of the process for making the PAN beads are given elsewhere. TEM specimens were obtained by vacuum impregnation with a low-viscosity epoxy and sectioning with a diamond knife. The beads can be observed unstained. However, different surface functionalities can be made evident by selective staining. Amide surface coverage was studied by staining in vapor of a 0.5.% RuO4 aqueous solution for 1 h. RuO4 does not stain PAN but stains, amongst many others, polymers containing an amide moiety.

Ambulatory Activity Monitoring

2009 ◽  
Vol 14 (2) ◽  
pp. 142-152 ◽  
Author(s):  
Johannes B.J. Bussmann ◽  
Ulrich W. Ebner-Priemer ◽  
Jochen Fahrenberg
Keyword(s):  
Physical Activity ◽  
Activity Monitoring ◽  
Main Stream ◽  
Computer Algorithms ◽  
Ambulatory Activity ◽  
Physiological Variables ◽  
Piezoresistive Sensors ◽  
Self Reports ◽  
Recent Developments ◽  
Objectively Measured

Behavior is central to psychology in almost any definition. Although observable activity is a core aspect of behavior, assessment strategies have tended to focus on emotional, cognitive, or physiological responses. When physical activity is assessed, it is done so mostly with questionnaires. Converging evidence of only a moderate association between self-reports of physical activity and objectively measured physical activity does raise questions about the validity of these self-reports. Ambulatory activity monitoring, defined as the measurement strategy to assess physical activity, posture, and movement patterns continuously in everyday life, has made major advances over the last decade and has considerable potential for further application in the assessment of observable activity, a core aspect of behavior. With new piezoresistive sensors and advanced computer algorithms, the objective measurement of physical activity, posture, and movement is much more easily achieved and measurement precision has improved tremendously. With this overview, we introduce to the reader some recent developments in ambulatory activity monitoring. We will elucidate the discrepancies between objective and subjective reports of activity, outline recent methodological developments, and offer the reader a framework for developing insight into the state of the art in ambulatory activity-monitoring technology, discuss methodological aspects of time-based design and psychometric properties, and demonstrate recent applications. Although not yet main stream, ambulatory activity monitoring – especially in combination with the simultaneous assessment of emotions, mood, or physiological variables – provides a comprehensive methodology for psychology because of its suitability for explaining behavior in context.

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