Date of Award


Publication Type

Master Thesis

Degree Name



Biological Sciences


Biology, Limnology.


Corkum, L. D.




Effects of nitrate and phosphate enrichment on the periphyton and macroinvertebrate communities were examined at six rivers flowing through both forested and agricultural land use areas in spring and autumn. Nutrient diffusing substrates (NDS) containing four nutrient treatments (C, N, P, N+P) were placed in the rivers for a 9 d incubation period. Upon retrieval, each NDS was analyzed for remaining nutrient content of the agar, periphyton accumulation (determined by chlorophyll a extraction), organic content (AFDM) of adhering materials, and macroinvertebrate colonization. NDS that were incubated in streams for 9 d were analyzed for residual nutrient content in spring and autumn. Spring samples retained more nutrients than autumn samples. To determine the distributional pattern of nutrients within the agar of the NDS, samples were removed and divided into three segments. No significant variation in vertical distribution of nutrients was detected within the agar of NDS. In spring, chlorophyll a values were consistently higher in agricultural rivers than in forested ones regardless of nutrient treatment. Significantly more Orthocladius and Dicrotendipes, colonized NDS in agricultural than forested rivers in spring. In the autumn, there was a significant interaction between land use and nitrogen for AFDM values obtained in the autumn. There were significantly more Tanytarsus, Dicrotendipes, and Caenis in the autumn than in the spring. Significantly more Tanytarsus, and Caenis colonized NDS that were incubated in agricultural than forested rivers. In summary, the nutrients that were added to agar in NDS remained stable over the duration of 256 d freezer storage, were retained in NDS after incubation in rivers, and did not segregate vertically. Periphyton and chironomid (Orthocladius, Dicrotendipes in the spring, Tanytarsus in the autumn) colonization were higher on NDS incubated in agricultural rivers than forested rivers. (Abstract shortened by UMI.)Dept. of Biological Sciences. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis1994 .B69. Source: Masters Abstracts International, Volume: 34-02, page: 0659. Adviser: L. D. Corkum. Thesis (M.Sc.)--University of Windsor (Canada), 1995.