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Life cycle plasticity and differential growth and development in marine and lacustrine populations of an Antarctic copepod


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Swadling, KM, McKinnon, D, De'ath, G and Gibson, JAE 2004 , 'Life cycle plasticity and differential growth and development in marine and lacustrine populations of an Antarctic copepod' , Limnology and Oceanography, vol. 49, no. 3 , pp. 644-655 .

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We examined life cycle plasticity in two populations of the copepod Paralabidocera antarctica, one of which
inhabits the coastal sea ice belt of Antarctica and the other of which has been isolated in a nearby saline lake for
several thousand generations. Similarities in the life cycles of the two populations included long overwintering
phases (.5 months) by late-stage nauplii, rapid development through the copepodid stages, and a short adult life
span of 2–3 weeks. Adults appeared in late spring or early summer and spawned and died soon after. However, the
life cycle of the lacustrine population was much less tightly regulated than at the marine site; animals were rarely
found living within the lake ice, and synchrony in the developmental cycle was diminished. It is likely that a
combination of factors, including ice hardness, a lack of predation threat, and a consistent food supply has freed
the lacustrine population from the constraints imposed by living within the ice cover. Instantaneous growth rates
calculated for the marine site showed a variable growth rate (0.04–0.14 d21). The lacustrine population in general
had faster growth rates than the marine population (0.10–0.26 d21) and reached maturity at a smaller size. This is
attributed, in part, to the higher environmental temperatures experienced by the lacustrine population.

Item Type: Article
Authors/Creators:Swadling, KM and McKinnon, D and De'ath, G and Gibson, JAE
Journal or Publication Title: Limnology and Oceanography
ISSN: 0024-3590
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Copyright 2004, by the American Society of Limnology and Oceanography, Inc. Definitive version is available online at

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