Univ., Diss.--Bremen, 2003. / Enth. außerdem 4 Originalpublikationen.

Graduation date: 1986

Thesis (M.Sc.) - Carleton University, 2006. / Includes bibliographical references (p. 54-74). Also available in electronic format on the Internet.

Amphipods are the most ubiquitous animals, after nematodes, on earth. Although there are several terrestrial amphipod species, most are aquatic. They are familiar animals in the water table exposed in cave environments and boreholes. The food source on which the amphipods depend was not directly observable in the cave environments frequented by the amphipods. In order to establish the role cave-dwelling amphipods play in ecology, the primary purpose of this study was thus to determine what cave-dwelling amphipods feed on. Amphipod, water and sediment samples were collected from five different caves, in the northern part of South Africa, namely Koelenhof Cave, Sterkfontein Cave, Ficus Cave, Peppercorn’s Cave, and Irene Cave. Following collection and transportation, resulting in zero amphipod mortalities, all of the samples were transferred to rectangular fish tanks stored in an environmental room, set up in such a way as to mimic the conditions in the caves as closely as possible. Long term adaptability and survival proved to be a successful undertaking, resulting in the death of only two amphipods per tank. Scanning electron microscopy was used to observe the mouthparts of the amphipods in order to begin establishing their feeding behaviour. Standard microtechniques were carried out to establish the general histological orientation and histology of the gastrointestinal tract. A Histochemical Fluorescent staining method was employed, and a reddish-orange fluorescence was observed, thereby indicating the presence of mucous in the GIT. Several feeding experiments were carried out, and it was established that on average amphipods can survive without a food source for a maximum of sixty ABSTRACT xv days. Through a series of different feeding experiments, it was determined that amphipods ingest bat faeces, leaf litter, sediment and yeast, with leaf litter producing the highest rate of survival. It was also observed that amphipods, regardless of body size, are predators, scavengers, and cannibals, which may provide an explanation as to why amphipods display evasive behaviour. Microbiology plays a vital role in determining what amphipods feed on, and therefore water, soil, and digestive contents of amphipods were studied using a wide array of microbiological analyses: Heterotrophic Plate Counts; Total Coliforms; Faecal Coliforms; Faecal Streptococci; Confirmatory test for Escherichia coli; Detection of Clostridium, Pseudomonas, and Salmonella. According to the South African Bureau of Standards, the quality of the water contained within all four of the caves in this study may not be used for human consumption prior to undergoing various purification processes. Once the role that cave-dwelling amphipods play in ecology has been firmly established it may then be possible to make use of amphipods as biological indicators, because since they inhabit cave streams and groundwater and are sensitive to pollutants, declines in their populations could indicate a decline in the water quality in their streams and surrounding groundwater supply. / Dr. J.F. Durand

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No description available.

The Fisheries Research Board of Canada has sponsored several expeditions in Canadian waters since 1947. A large number of specimens of euphausids and pelagic amphipods have been collected from the various expeditions. [...]

No description available.

The effects of salinity on the physiology and ecology of the mud-dwelling estuarine animal Corophium volutator (Pallas), a crustacean amphipod, have been investigated. A study of the effects ot salinity on the distribution and abundance of C. volutator on the estuary of the River Ythan, Aberdeenshire, indicates that 2‰ is a critical minimum salinity controlling its distribution. In areas with salinities between 2 and 5‰ C. volutator was present, but in reduced numbers. In areas with salinity greater than 5‰ , the distribution and abundance of C. volutator were controlled by the nature of the substrate; however, in areas with suitable substrates, but where the salinity was below 5‰ , the effects of salinity override the effects of the substrate. Experimental studies indicated that, if supplied with mud, it will survive the salinity range of 2 - 50‰, and without mud, the range 7.5 - 47.5‰. Moulting occurred in salinities of 2.6 - 46‰ , but most frequently in tho range 5 - 20‰ . Growth occurred at a maximum rate in 15.4 o/oo and only slightly slower at 4.4 and 30.6‰ ; but below 4.4‰ the growth rate was progressively reduced. The effects of salinity on the various stages in the life cycle are discussed. Freezing point studies show C. volutator to be a hyperosmotic regulator, having a tissue tolerance range of 13 - 50‰ . The effect of size, sex, feeding and moulting on the freezing point have been investigated. C. volutator was found to produce urine hypoosmotic to the blood when acclimated to low salinities, and isosmotic urine at salinities above 20‰ . Over a range of salinities from 1 - 35‰ , C. volutator was found to maintain Na+, K+,Ca ++,Cl-, more concentrated than the medium, and Mg++ less concentrated. The restricted permeable areas of the cuticle have been localised by silver staining. The oxygen consumption of animals of the same size, at the same level of activity, and at the same temperature, did not differ significantly between animals in different salinities. A salinity preference range of 10 - 30‰ has been demonstrated. Relevant literature on estuarine life, and osmoregulation of crustacea is reviewed. The adaptations of C. volutator to an environment with varying salinity are discussed.

Thesis (M.Sc. (Zoology & Entomology)) - Rhodes University, 2009.