SHIFT FROM CHLOROPHYTES TO CYANOBACTERIA IN BENTHIC MACROALGAE ALONG A GRADIENT OF NITRATE DEPLETION(1)
© 2008 Phycological Society of America.
| Veröffentlicht in: | Journal of phycology. - 1966. - 44(2008), 1 vom: 25. Feb., Seite 38-44 |
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| Weitere Verfasser: | , |
| Format: | Online-Aufsatz |
| Sprache: | English |
| Veröffentlicht: |
2008
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| Zugriff auf das übergeordnete Werk: | Journal of phycology |
| Schlagworte: | Journal Article Lyngbya benthic algae cyanobacteria macroalgae nitrogen river |
| Zusammenfassung: | © 2008 Phycological Society of America. A survey of the spatial distribution of benthic macroalgae in a fluvial lake of the St. Lawrence River (Lake Saint-Pierre, Quebec, Canada) revealed a shift in composition from chlorophytes to cyanobacteria along the flow path of nutrient-rich waters originating from tributaries draining farmlands. The link between this shift and changes in water quality characteristics was investigated by sampling at 10 sites along a 15 km transect. Conductivity, current, light extinction, total phosphorus (TP; >25 μg P · L(-1) ), and ammonium (8-21 μg N · L(-1) ) remained fairly constant along the transect in contrast to nitrate concentrations, which fell sharply. Filamentous and colonial chlorophytes [Cladophora sp. and Hydrodictyon reticulatum (L.) Bory] dominated in the first 5 km where nitrate concentrations were >240 μg N · L(-1) . A mixed assemblage of chlorophytes and cyanobacteria characterized a 1 km transition zone where nitrate decreased to 40-80 μg N · L(-1) . In the last section of the transect, nitrate concentrations dropped below 10 μg N · L(-1) , and cyanobacteria (benthic filamentous mats of Lyngbya wollei Farl. ex Gomont and epiphytic colonies of Gloeotrichia) dominated the benthic community. The predominance of nitrogen-fixing, potentially toxic cyanobacteria likely resulted from excessive nutrient loads and may affect nutrient and trophic dynamics in the river |
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| Beschreibung: | Date Completed 05.04.2016 Date Revised 04.04.2016 published: Print Citation Status PubMed-not-MEDLINE |
| ISSN: | 1529-8817 |
| DOI: | 10.1111/j.1529-8817.2007.00429.x |