Thesis
Zooplankton in Columbia-Snake River system reservoirs with special emphasis on the invasive copepod Pseudodiaptomus forbesi
Washington State University
Master of Science (MS), Washington State University
2012
Handle:
https://hdl.handle.net/2376/100621
Abstract
The Asian copepod Pseudodiaptomus forbesi has recently become established in the Columbia River, however little is known about its basic ecology and potential impacts on native ecosystems. We therefore undertook a 2-year field study of the mesozooplankton communities of four reservoirs in the Columbia-Snake River system. We examined the mesozooplankton communities in relation to various environmental variables (temperature, dissolved oxygen, chlorophyll a, pH, conductivity, and freshwater discharge), with particular emphasis on determining the seasonal variation in distribution and abundance of P. forbesi. Monthly plankton tows were collected in triplicate, along with CTD casts, from July 2009 to June 2011 in each reservoir. P. forbesi was present and abundant in three reservoirs, with the zooplankton community of the fourth reservoir being made up entirely of what are believed native species. NMDS analysis indicated that temperature and dissolved oxygen were most strongly associated with variation in the zooplankton communities. The composition and seasonal succession of zooplankton were similar in the three invaded reservoirs: a bloom of rotifers occurred in spring, native cyclopoid and cladoceran species peaked in abundance in the summer, and P. forbesi was most abundant in the late summer and autumn. An analysis of stage distributions indicated that P. forbesi had a single generation per year. In the uninvaded reservoir, total zooplankton abundance was very low year-round. Although the broader ecosystem-level effects (e.g., on higher trophic levels such as salmon) of the invasive P. forbesi are unknown, this copepod's broad distribution, high abundance and potential competition with native copepods make it a concern for scientists and managers in the Columbia-Snake River System.
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Details
- Title
- Zooplankton in Columbia-Snake River system reservoirs with special emphasis on the invasive copepod Pseudodiaptomus forbesi
- Creators
- Joshua Edward Emerson
- Contributors
- Stephen M. Bollens (Degree Supervisor)
- Awarding Institution
- Washington State University
- Academic Unit
- Environment, School of the (CAHNRS)
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University; Pullman, Wash. :
- Identifiers
- 99900525060701842
- Language
- English
- Resource Type
- Thesis