A comparative, limnological study of five, small, eutrophic lakes in the Interior of British Columbia was made over a period of two summers. Detailed morphometrical, physical, chemical and biological data are given. The effect of a rotenone base compound on the fauna of two of these lakes is shown both qualitatively and quantitatively by comparing them with the faunas in other lakes. A complete eradication of the fish in the lakes was obtained. Certain species of plankton and bottom organisms were killed by the poison but sufficient numbers survived to re-populate the lakes. The plankton populations did not revert to the previous level of abundance in the year following. The effect of the absence of coarse fish on certain shore organisms and Gladocera was indicated. / Science, Faculty of / Zoology, Department of / Graduate

The Lea Navigation in the north-east of London, a canalised reach of the River Lea, is affected by episodes of very low levels of dissolved oxygen. The problem was detected by the Environment Agency in the stretch from the confluence with Pymmes Brook (which receives the final effluent of Deephams sewage treatment works) to the Olympic area (Marshgate Lane, Stratford). In this project, possible causes and sources of the poor water quality in the Lea Navigation have been investigated using a multi-parameter approach. A study of physico-chemical parameters, obtained from Environment Agency automated monitoring stations, gave a clear picture of the poor river water quality at three sites in this reach. River water ecotoxicity to the freshwater alga Pseudokirchneriella subcapitata was determined by algal growth inhibition tests, following the OECD guidelines. Moreover, a novel protocol was developed which involved the use of E. coli biosensors (CellSense) operating at a lower potential than the standard protocol and using pre-concentrated river water samples. This protocol is promising and it has the potential to be a useful tool to determine the toxicity of contaminants at environmental concentrations. Furthermore, the developed protocol is a rapid, easy to perform bioassay, with potential application in achieving the aims of the Water Framework Directive (WFD). In addition to the data from the Environment Agency automatic monitoring stations and the laboratory-based tests, two in situ monitoring approaches were performed: 1) a detailed spatial seasonal monitoring of physico-chemical parameters of river water at twenty-three sites, and 2) algal growth inhibition tests, with algae entrapped in alginate beads, at seven monitoring stations. Results showed chronic pollution, and identified polar compounds in the river water and high bacterial concentrations as possible causes of low dissolved oxygen levels. This study confirmed the negative impact of Deephams STW (throughout Pymmes Brook) on the water quality of the Lea Navigation. However, there was evidence of other sources of pollution, in particular Stonebridge Brook was identified as uncontrolled source of pollution and untreated wastewater. Other possible sources include Old Moselle Brook, diffuse pollution from surface runoff, boat discharges and other undetected misconnections. Finally, in the light of the WFD, this project provides a case study on the investigation of river water quality, providing evidence that the multiparameter approach is reliable, and low cost approach for the monitoring of freshwater bodies.

No description available.

No description available.

Body size influences virtually all aspects of the autecology of material flow by organisms. Thus, size classes may be considered as alternatives to grouping by trophic level, function or taxonomy to describe the structure and function of communities. The general intent of this thesis is to assess the role of body size in the dynamics of radiophosphorus in the freshwater plankton. To calculate a priori estimates of the fluxes of phosphorus through size classes of plankton, the rates of assimilation and excretion of laboratory cultures of algae and cladocerans were measured, and regressed on body mass (W). In both groups, assimilation increased as W('0.75). The turnover of body phosphorus was described as a two-compartment system. The turnover rates of the small (2-5% of body P) fast turnover pool, the large (95-98%) slow turnover pool, and that of the body phosphorus fell proportionately to W('- 1/4) in algae and W('- 1/2) in zooplankton. Field tests of allometric models of radiophosphorus flow were conducted by following the redistribution of radioactivity among 11 size fractions of enclosed epilimnetic assemblages over 5 to 6 days. Concentration of the tracer in the biomass declined with size soon after addition and gradually shifted to a uniform distribution within 3 days. A model that makes no a priori assumptions as to the trophic structure of the system, i.e. all size classes are at the same trophic level, predicted these dynamics better than one that assumes trophic position to increase with size. Further analyses indicated that explicit treatment of the physiological allometry and size distribution of broad functional groups of plankton are needed to improve the descriptive power of the model further.

No description available.

Thesis (Ph.D.)--Michigan State University. Environmental Engineering, 2008. / Title from PDF t.p. (viewed on July 16, 2009) Includes bibliographical references. Also issued in print.

Thesis (M.S.)--University of Wisconsin--La Crosse, 1972. / Digitized and made available by the University of Wisconsin--La Crosse, Murphy Library. Includes bibliographical references (leaves 40-41). Online version of print edition.

Sida crystallina, a cladoceran, is found in densities up to 45 per square centimeter underneath lilypads (Nuphar poly-sepalum) in Marion Lake, British Columbia. Floats, boats, and other artificial substrates are rapidly colonized by Sida to densities comparable to those underneath lilypads. Sida only persists underneath horizontal-lying substrates. On substrates receiving direct sunlight, filamentous algae grow and displace Sida. The high densities of Sida under lilypads attract several predators, both vertebrate and invertebrate; however, the overall Sida populations appears to be unaffected by predation. At the end of the summer, the population declines rapidly, possibly due to predation as well as to natural mortality. Rapid flushing occurs in Marion Lake after a rainstorm, and lilypads appear to serve as a refuge from the current. It is also likely that lilypads serve as feeding locations in areas of relatively high phytoplankton concentrations (compared with the open water of the lake). The observed colonization behaviour would then be selectively advantageous if feeding sites are in short supply and intra-specific competition is high. The dynamics of colonization were monitored four times over the summer, and population growth parameters were obtained concurrently. From a comparision of these, it seems that most of the observed growth on the artificial substrates is due to immigration and not to reproduction. All population drops are due to emigration. From an experiment testing the rate of colonization as a function of the distance to the nearest Nuphar bed, it appears that the colonization is by clumps of Sida at the mercy of the lake currents. During periods of persistent wind, colonization is most rapid in areas where these clumps tend to be concentrated by the wind. Otherwise, the artificial substrates nearest to the Nuphar beds are colonized first. The population statistics obtained over the summer show that after an initial period of rapid growth, the population growth rate becomes very slow (probably not much more than one birth per individual). It is likely that Sida is exploiting its environment to a maximum by maintaining its population as near as possible to its carrying capacity. / Science, Faculty of / Zoology, Department of / Graduate

Two benthic amphipod species (Crangonyx richmondensis var occidentalis Hubricht and Harrison and Hyalella azteca Saussure) live together in Marion Lake, but, as previous workers have shown, differ markedly in the distribution of their numbers. The aim of the study was to compare the behaviour of the two species and to see if any differences might account for the differences in distribution. Particular attention was paid to movement and feeding behaviour. Crangonyx was equally abundant on the bottom at all depths in the lake; Hyalella was abundant in the shallows (1m) and scarce in the deeper waters ( 3 m). Numbers of each species differed among areas in the lake. Crangonyx usually moved by crawling over the mud, and seldom swam. It seemed to find food by its smell or motion or both, and to recognize food by touch or taste. It attacked living prey by pouncing on it and grasping it with its gnatho-pods. In contrast, Hyalella moved mainly in a series of swims and pauses. Hyalella fed by grazing on the mud and rooted aquatics, and ingesting detritus. Both species moved away from sources of light. When food was present in various distributions, the search patterns of Crangonyx differed: some animals turned back and thoroughly searched the area where they had just found food; others crawled along a relatively straight path; yet others behaved in an intermediate manner. In general, Crangonyx seemed to be quicker at finding clumped food than uniformly distributed food. In the absence of food, some individual Crangonyx turned more than others. Hyalella searched by swimming, pausing on a surface, and remaining where food was present. Probably neither species moves frequently between depth zones, although both species are mobile enough to do so. Marked amphipods placed at 1 - and 3-m depths in the lake were recaptured in samples taken 1 and 4 m from the release point after an hour. Fewer marked amphipods of either species were recaptured in the deep area than in the shallow area, indicating that they left the deep area faster. Of the behavioural differences noted, only the difference in feeding habits between the species seems likely to account, at least in part, for the difference in the distribution of their numbers. Recent work by Dr. Hargrave has shown that epibenthic algal production decreases with depth, though not as sharply as Hyalella numbers. In laboratory substrate-choice experiments, Hyalella chose areas of abundant food. Its assimilation efficiency and growth differed when it fed on different sediment microflora. Dr. Gruendling found that the abundance of the algal groups in Marion Lake differed with depth. The distribution of Hyalella may be related to the distribution of certain species of algae in its diet. The distribution of food for Crangonyx is unknown. / Science, Faculty of / Zoology, Department of / Graduate