Given the prominent role of nitrogen in the eutrophication of aquatic systems, recent increases in nitrogen loading to freshwaters are of concern. A comparison of nitrogen retention in freshwaters in North America and Europe shows that wetlands retain the greatest proportion of their nitrogen load, followed by lakes and then rivers. A comparison of the relative importance of nitrogen retention mechanisms found denitrification to be responsible for the greatest proportion followed by nitrogen sedimentation and then uptake by aquatic plants. A more in-depth examination of denitrification in the littoral sediments of Lake Memphremagog in Quebec, using the N2 flux technique, found an average denitrification rate of 111 mumol N m-2 h-1. Denitrification rates were positively related to the % organic matter of the sediment, temperature and macrophyte biomass density and negatively related to depth. These results, in combination with a review of the literature indicate that denitrification rates are higher in littoral than profundal sediments.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.30739 |
| Date | January 2000 |
| Creators | Saunders, Darla L. |
| Contributors | Kalff, Jacob (advisor) |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Master of Science (Department of Biology.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001764856, proquestno: MQ64444, Theses scanned by UMI/ProQuest. |
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