The general goal of this thesis was to examine and quantify the role of rooted submerged aquatic macrophytes in the cycling of metals in the littoral zone. An empirical study using data from an extensive literature survey showed that aquatic plants do not differ markedly in element composition from the sediments in which they grow, and that during uptake the plant's roots do not discriminate between elements essential and not essential for growth. The organic content, pH and redox potential of the sediments were shown to affect the bioavailability of metals to the plants. Biomass density was used to categorize species to assess broad patterns in plant-sediment metal relationships. It was found that the presence/absence of an understory contributed variation to the plant-sediment metal relationships. The role of rooted macrophytes as vectors for various elements between the sediments and attached epiphyte was quantified by growing Myriophyllum spicatum in radio-labelled sediments. This species was found to be a link between the sediments and attached epiphytes for the 4 elements studied (Co, Cs, Eu and Mn). Finally, the export of dissolved metals from weedbeds during plant senescence was quantified using a mass balance approach. It was found that approximately 15% to 30% (depending on the metal) of the metal inventory of the plants at maximum seasonal biomass was lost as dissolved compounds during senescence. During the growing season the macrophyte beds were net sources of metals to the lake, but were net sinks annually.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.39449 |
| Date | January 1992 |
| Creators | Jackson, Leland J. (Leland Joseph) |
| 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 | Doctor of Philosophy (Department of Biology.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001318250, proquestno: NN80450, Theses scanned by UMI/ProQuest. |
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