A quantitative ecological study of aquatic fungi from Broadcove River with emphasis on representatives of the genus Saprolegnia

Maestres, Luisa E. (1977) A quantitative ecological study of aquatic fungi from Broadcove River with emphasis on representatives of the genus Saprolegnia. Masters thesis, Memorial University of Newfoundland.

[English] PDF (Migrated (PDF/A Conversion) from original format: (application/pdf)) - Accepted Version Available under License - The author retains copyright ownership and moral rights in this thesis. Neither the thesis nor substantial extracts from it may be printed or otherwise reproduced without the author's permission. Download (20MB) [English] PDF - Accepted Version Available under License - The author retains copyright ownership and moral rights in this thesis. Neither the thesis nor substantial extracts from it may be printed or otherwise reproduced without the author's permission. (Original Version)

Abstract

The fluctuation in the level of representatives of species belonging to the fungal Order Saprolegniales was monitored in Broadcove River over a one year period. Some physical and chemical parameters of the stream were also monitored. -- The technique used was designed to provide a quantitative estimate of the number of fungal propagules suspended in the water. Attempts were made to minimize the loss of the viable propagules during processing of the sample. The number of these viable propagules was assumed to give an indication of the level of fungal growth or reproductive activity in the stream just prior to or at the time of collecting the water sample. -- Centrifugation, resuspension and plating of the sample on a medium selective for species of the genus Saprolegnia Nees v. Esenbeck were followed by the rapid isolation and subculturing of the colonies as they appeared. Further processing was carried out to obtain sexual structures of the fungi in pure culture for purposes of identification. -- Temperature, level of trace elements, sodium, phosphates, dissolved oxygen and total carbon content of the water (chemical oxidation demand) were found to have an effect on the total number of propagules, and on the number of individual species, in some cases. However, at the lowest recorded temperature, the total number of propagules was reduced regardless of other environmental conditions. -- The species fell into three main groups with relation to the temperature of the stream at which their maximum abundance occurred. A small number of species, the winter species, was most frequent when the stream temperature was from 1.5° to 2.5°C. The most numerous category was made up by the intermediate temperature species, or those species which were recorded most frequently at 13°C. Another small group of species, the warm weather species, was most abundant when the stream temperature was 17°C. -- Occurrence of heavy rains in spring (March) and autumn (September) resulted in an increase in the level of trace elements in the stream and coincided with the isolation of species not otherwise recorded. Resting propagules of these species washed in from the surrounding soil or present in the water may have been stimulated to germinate and grow by the increased level of micronutrients.

Actions (login required)

View Item