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Presented at the NABS Annual meeting, Pittsburgh, Pennsylvania, 2002
in Lentic Ecology
RECOLONIZATION OF AZOIC SEDIMENTS BY MEIOFAUNA IN THE HYDROPSAMMON OF OTSEGO LAKE, NEW YORK.
M.D. Cornwell1,2 and T.G. Horvath2. 1Department of Animal Science, State University New York, Cobleskill, New York 12043, 2Biology Department, State University New York, Oneonta, New York 13820
Hydropsammic meiofaunal communities have to recolonize disturbed sediments following changes in lake level and increased wave action. We monitored recolonization in azoic sediments (defaunated by heating; organic matter left intact) in 50–ml centrifuge tubes placed in the hydropsammon (0.25–0.5 m deep, within 5 m of shore). Treatments included drift (open tops, closed sides), interstitial (closed top, mesh side; 500 ìm) and control (open top, mesh side). Samples were collected at 0, 1, 4 and 8 wk, along with four 50–ml ambient samples. Total meiofauna abundance increased steadily from wk0 to wk8. Recolonization was complete by wk4 (Ambient vs. Treatments; p>0.47). Taxa diversity peaked by wk4 but declined by wk8. No treatment effect was observed for total meiofauna abundance (2–way ANOVA, p=0.12). However, oligochaetes and Aeleosoma abundances were higher in interstitial than in drift treatments (p=0.01 and p=0.06, respectively) by wk4. Cyclopoid, harpactacoid, and ostracod abundances tended to be higher in drift than in interstitial treatments (all nonsignificant) by wk8. Chironomid abundance was higher in drift than in interstitial treatments (p=0.02). Tardigrades showed no trends, but appear to be slow colonizers. It appears annelids better colonize via endobenthic dispersal, whereas crustaceans and chironomids better colonize via epibenthic dispersal.
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