Environmental conditions may change markedly within aquatic ecosystems during a 24-h period. Solar radiation varies from high intensity at midday to darkness. Surface temperatures and concentrations of dissolved gases also may fluctuate between extremes of day and night, especially in shallow, littoral areas. Organisms within the lake may move vertically or otherwise relocate themselves in response to these environ-mental changes. For example, various species of zooplankton undergo marked vertical migrations during a 24-h cycle [cf., Hutchinson (1967) and Wetzel (1983)]. These movements are keyed to light, food availability, and predation pressures. In this exercise, we shall examine some of the relationships between these factors and the vertical movements of zooplankton in a lake.
KeywordsDissolve Oxygen Concentration Vertical Migration Diurnal Change Total Solar Irradiance Lake System
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- Hutchinson, G.E. 1967. A Treatise on Limnology. Vol. 2. Introduction to Lake Biology and the Limnoplankton. Wiley, New York. 1115 pp.Google Scholar
- Wetzel, R.G. 1983. Liminology. Saunders Coll., Philadelphia. 860 pp.Google Scholar
- Worthington, E.B. 1931. Vertical movements of freshwater macroplankton. Int. Rev. ges. Hydrobiol. Hydrogr. 25: 394–436.Google Scholar