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Presented at the NABS Annual meeting, Athens, Georgia, 2003
in Hyporheic Processes
Investigating temporal and spatial patterns of a shallow groundwater ecosystem: emphasis on water chemistry, ciliates, and meiofauna.
K.P. Wilson, O. Andrushchyshyn, and D.D. Williams. Surface and Groundwater Research Group, Division of Life Sciences, University of Toronto at Scarborough, Scarborough, Ontario, Canada M1C 1A4
Nested piezometers at depths of 20, 40, 60, 80, and 100 cm were used to collect water chemistry, and ciliates, whereas a standpipe corer was used to collect meiofauna at similar depths. Samples were collected bimonthly from June 2002 from a shallow groundwater ecosystem located in southern Ontario, Canada. Preliminary data show dissolved oxygen (mg/l), temperature (C), conductivity (µS) decreasing with depth and pH showing no change. However, only temperature changed seasonally, decreasing between 1 and 3 degrees depending on depth. Nitrate decreased with depth from 1.5 mg/l (±0.1SE) at 20cm to 0.08 (±0.03) at 100cm, ammonia increased with depth from 0.15 (±0.05) to 1.1 (±0.5), sulfide also increased with depth from 0.03 (±0.02) at 20cm to 0.10 (±0.01) at 100cm. Phosphorus showed no difference between depths ranging from 0.7-0.8 mg/l, but did show a significant change by collection (p<0.0001, f=10.25, n=42). Ciliate data suggest a change in the community at different depths and over time. The number of ciliate species decreased with increasing depth and was dominated by Loxodes spp., Cyclidium spp., and Urotricha spp. Meiofauna was dominated by Nematoda Dorylaimus spp., Cylindrolaimus spp. and Mononchulus spp.), Copepoda (Harpacticoda), and Ostracoda (Cypridopsis sp., Potamocypris sp., and Candocyprinotus sp.).
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