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The Reproductive Cycle of Daphnia in An Arctic Pool
- Stross, R. G., Kangas, D. A.
- Ecology 1969 v.50 no.3 pp. 457-460
- Daphnia, diapause, heat sums, lakes, metabolism, overwintering, population growth, temperature, Arctic region
- The reproductive cycle of Daphnia middendorffiana living in an arctic pool and an arctic lake is essentially the same. An overwintering generation produces one brood of young before shifting to produce broods of embryos which enter diapause. The pool warms more rapidly than the lake and has twice the number of day—degrees above 0°C. The higher temperature acts only to accelerate the development rate of the Daphnia, and the reproductive shift occurs in mid—July rather than in late August. The restriction of population growth to one brood of young in the warmer pool and colder lake is used to illustrate the hypothesis that arctic temperature influences productivity by controlling life cycle rather than by restricting rates of metabolism.