Grazing and nutrient interactions in controlling the activity and composition of the epilithic algal community of an arctic lake1
The effects of grazing by the snail Lymnaea and enrichment with N and P were examined in the epilithic algal community of an arctic lake. Increased nutrients raised chlorophyll a levels and primary production and favored the growth of filamentous green algae and coccoid blue‐greens. Intensive grazin...
| Published in: | Limnology and Oceanography |
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| Main Author: | |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
Wiley
1983
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| Online Access: | http://dx.doi.org/10.4319/lo.1983.28.1.0133 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.4319%2Flo.1983.28.1.0133 https://aslopubs.onlinelibrary.wiley.com/doi/pdf/10.4319/lo.1983.28.1.0133 |
| Summary: | The effects of grazing by the snail Lymnaea and enrichment with N and P were examined in the epilithic algal community of an arctic lake. Increased nutrients raised chlorophyll a levels and primary production and favored the growth of filamentous green algae and coccoid blue‐greens. Intensive grazing reduced algal concentration and activity. Grazing increased the relative abundance of small green and blue‐green coccoid cells at the expense of larger (>20 µ m) diatoms. Photosynthetic activity of snail feces was 77–79% that of ungrazed algae per unit mass. Split chamber experiments and measurements of dissolved phosphorus indicated that nutrients released in grazing may be tightly recycled within snail guts or on the rock surface, rather than transferred into the water. Radioisotope tracing was used to develop a simple energy budget for Lymnaea. Despite viable gut passage of some of the algae, the snail was an efficient grazer, assimilating 68% and incorporating 25% of ingested carbon. |
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