![]() ![]() Severus Sandor, Mignon Sandor, Valentina Mihai Onica, Bogdan Brad, Traian Microcosm experiments approach to quantify nitrogen leaching from mineral and organic fertilized soil The results indicate that such behavioural changes may be predictive of effects at the ecosystem level. Consequently, the fast and cost-effective video tracking methodology may be applied for screening for potential effects of a wider range of pesticides and other stressors on the locomotory behaviour of freshwater invertebrates. For the species of invertebrates investigated, it was possible to extrapolate directly from pyrethroid-induced behavioural changes observed in the laboratory to drift under more realistic conditions in stream microcosms. sulphurea (100 ng L(-1)) are all within expected environmental concentrations. Although the concentrations observed, typically Gammarus pulex>Heptagenia sulphurea. ![]() ![]() Pesticides are transported from crop fields to adjacent streams via surface run-off, drains, groundwater, wind drift and atmospheric deposition and give rise to transient pulse contamination. Nørum, Ulrik Friberg, Nikolai Jensen, Maria R Pedersen, Jakob M Bjerregaard, Poul Similarity of tr.īehavioural changes in three species of freshwater macroinvertebrates exposed to the pyrethroid lambda-cyhalothrin: laboratory and stream microcosm studies. Two second-order transformation rate coefficients-kb, based on total plate counts, and kA, based on periphyton-colonized surface areas-were used to compare xenobiotic chemical transformation by laboratory-developed ( microcosm) and by field-collected microbiota. In general, hydrogen limitation is found to increase with increasing TCE concentration and with bioaugmentation, andĬOMPARISON OF MICROBIAL TRANSFORMATION RATE COEFFICIENTS OF XENOBIOTIC CHEMICALS BETWEEN FIELD-COLLECTED AND LABORATORY MICROCOSM MICROBIOTA Over a wide range of experimental conditions and dechlorination steps, SRS appears to induce relatively little hydrogen limitation, thereby facilitating relatively quick conversion of TCE to ethene. Competitive inhibition is found to increase in significance as TCE concentrations increase however, inclusion of Haldane inhibition is not supported. Results quantify the benefit (i.e., increased stepwise dechlorination rate) due to both bioaugmentation and the presence of higher sulphate concentrations. In calibrating the model to over 60 of the microcosm experiments, lumped parameters were employed to quantify the effect of key factors on the conversion rate of each chlorinated ethene in the TCE degradation sequence. This research presents a numerical model designed to simulate the main processes occurring in the microcosms, including substrate fermentation, sequential dechlorination, toxic inhibition, and the influence of sulphate concentration. individuals were significantly negatively associated with the concentration of total petroleum hydrocarbons (Spearman correlation coefficients, p 500 mg/L) on TCE dechlorination. The total meiofaunal density, nematode density, and number of Bolbolaimus spp. Cluster analysis showed similar results for nematode and meiofaunal communities. (37.1%) were dominant among the nematodes. However, SIMPROF analysis showed no significant difference between the two groups ( p > 0.05). Cluster analysis divided the microcosms into group 1 (control, 0.5%, 1%, 2%, and 4% microcosms) and group 2 (8%, 15%, and 20% microcosms). ![]() The density of nematodes was similar to that of the total meiofauna. The average density of total meiofauna in the 8%, 15%, and 20% microcosms was lower than the density in the control. The average density of total meiofauna in the experimental microcosms diluted with 0.5%, 1%, 2%, and 4% contaminated seawater was higher than the density in the control. We administered a seawater solution that had been contaminated with total petroleum hydrocarbons to seven treatment groups at different concentrations, while the control group received uncontaminated filtered seawater. We examined the effects of crude oil contamination on community assemblages of meiofauna and nematodes after exposure to total petroleum hydrocarbons in the laboratory. Kang, Teawook Oh, Je Hyeok Hong, Jae-Sang Kim, Dongsung Responses of meiofauna and nematode communities to crude oil contamination in a laboratory microcosm experiment The microcosm lab provides student-centered approach with opportunities for collaborative learning and to develop critical communication skills. The traditional range of marine microcosm laboratory experiments is presented as an ideal environment to teach the entire analysis process. Extending the Marine Microcosm LaboratoryĮRIC Educational Resources Information Center ![]()
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