Record Details
Structure, abundance, and distribution of pelagic zooplankton in a deep, oligotrophic Caldera Lake
ScholarsArchive at Oregon State University
| Field | Value |
|---|---|
| Title | Structure, abundance, and distribution of pelagic zooplankton in a deep, oligotrophic Caldera Lake |
| Names |
Karnaugh, Elena N.
(creator) Larson, Gary L. (advisor) |
| Date Issued | 1988-03-14 (iso8601) |
| Note | Graduation date: |
| Abstract | From July 1985 to April 1987 the pelagic zooplankton community of Crater Lake, Oregon was studied to determine taxonomic structure, absolute and relative densities, and spatial and temporal distributional patterns. Samples were collected using vertically-towed zooplankton nets. The community structure consisted of two cladoceran and nine rotifer species, which were either phytophagous, polyphagous, or triptophagous; none was predaceous. The community numerically was dominated by rotifers, and the majority of the populations occurred within the hypolimnion. Taxonomic structure, abundance, and distribution of the zooplankton community were relatively stable. While the stability was attributed to the extremely high numerical dominance of the rotifer, Keratella cochlearis, some of the observed variations were attributed to depth and season. This stability may be short-term. Historic data suggest that the density of the cladoceran, Daphnia pulicaria. is cyclic, being highly abundant in some years and rare in others. During this study, D. pulicaria abundances were low but appeared to be on an increasing trend. Changes in Daphnia densities may be due to fluctuations in food supply or in densities of the zooplanktivorous kokanee (Oncorhynchus nerka kennerlyi). Such fluctuations in the daphnid population may be related to and integrated with changes and fluctuations in the zooplankton and phytoplankton communities, primary production, and water clarity. |
| Genre | Thesis/Dissertation |
| Identifier | http://hdl.handle.net/1957/39343 |
