Abstract
Epilithic diatoms were sampled at 48 sites along the St. Lawrence River, from Salaberry de Valleyfield to Quebec City, in an attempt to determine how diatom assemblages were related to measured water quality variables. Canonical correspondence analysis was used to explore the relationships between environmental variables and patterns in the epilithic diatom assemblages. 'Distance downstream from Cornwall' was determined to be the strongest variable influencing the structure of epilithic diatom assemblages, likely due to the effect of tides (favouring aerophilic species) closer to the river outlet. Variables related to pollution (suspended solids, fecal coliforms, chlorophyll a) also explained significant (P < 0.05) amounts of variance in the diatom assemblages. The optima of common diatom species to suspended solids were explored further. Reconstructive models using weighted-averaging calibration and regression illustrated that 'distance from Cornwall' and concentrations of suspended solids, fecal coliforms, and chlorophyll a, the most influential variables, could be inferred from the diatom assemblages. When compared with the inference models developed for pollution variables using epiphytic diatom assemblages (attached to macrophytes or Cladophora), the epilithon model appears to perform better.
Original language | English (US) |
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Pages (from-to) | 251-257 |
Number of pages | 7 |
Journal | Canadian Journal of Botany |
Volume | 76 |
Issue number | 2 |
DOIs | |
State | Published - 1998 |
Bibliographical note
Funding Information:1 Supported in part by Research Grant AM09363 from the National Institute of Arthritis, Metabolism, and Digestive Diseases, National Institutes of Health, and by Grant GB-28458X from the National Science Foundation. S.S.S. was supported by USPHS Training Grant GM1531. * Present address: Department of Cellular Biology, Scripps Clinic and Research Foundation, 10666 N. Torrey Pines Road, La Jolla, Calif. 92037.
Keywords
- Calibration
- Diatoms
- Epilithic
- Rocks
- St. Lawrence River
- Water quality