Recovery of Daphnia galeata mendotae in two historically acid and metal contaminated lakes after liming

Conference · Sat Dec 31 04:00:00 EST 1994

OSTI ID:40108

Welsh, P G ^[1]; Yan, N; Hangang, L ^[2]; Dixon, D G

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1. Univ. of Waterloo, Ontario (Canada)
2. Ontario Ministry of Environment and Energy, Dorset (Canada). Dorset Research Centre

Daphnia galeata mendotae (DGM) has recently re-appeared in Hannah and Middle Lake, two lakes historically stressed by acid and metals. These lakes were limed in the early 1970s. Since then, the lakes have remained non-acidic but metal levels have declined monotonically. DGM became a dominant zooplankton species in Hannah Lake approximately 5 years before Middle Lake. One hypothesis for this temporal displacement in recovery is available metal concentrations regulating recovery in the two lakes. The authors examined the chronic toxicity of Cu, Cd, and Ni mixtures to DGM in the laboratory with lake water manipulated to correspond to metal concentrations in successive 4--5 year increments (1976, 1981, 1985, 1989, and 1993). Cultures of DGM were established from both lakes. Survivorship and, especially, number of living offspring produced were sensitive indicators of past metal conditions. Conditions representative of 1976 lake water (immediately post-liming) were acutely lethal to both DGM populations. Hannah Lake DGM had higher survivorship and number of live offspring produced for all of the remaining simulated lake conditions. These results correspond well with field assessment of the timing of recovery of DGM in both lakes.

• OSTI ID: 40108
• Report Number(s): CONF-9410273--
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
56 BIOLOGY AND MEDICINE
APPLIED STUDIES
ACIDIFICATION
BIOLOGICAL RECOVERY
CADMIUM
COPPER
DAPHNIA
ECOLOGICAL CONCENTRATION
LAKES
LIMING
NICKEL
ONTARIO
TOXICITY
WATER POLLUTION