SS3.18 Habitat Coupling in Lakes
Date: Thursday, June 13, 2002
Time: 11:00:00 AM
Location: Esquimalt
 
HairstonNG, Cornell University, Ithaca, NY, USA, ngh1@cornell.edu
Kearns, C, M, Cornell University, Ithaca, NY, USA, cmk4@cornell.edu
Perry, L, J, Cornell University, Ithaca, NY, USA, ljperry@emory.edu
 
DETERMINANTS OF TEMPORAL DISPERSAL VIA DIAPAUSING EGGS: SEDIMENTATION RATE, BIOTURBATION DEPTH, AND ANTHROPOGENIC EFFECTS
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Zooplankton diapausing eggs in lake sediments can hatch after as much as several decades and may influence the persistence of species within a community and genotypes within a population. Processes within the sediments during the period of egg burial are critical in determining the duration of egg viability and probability of being mixed to the sediment-water interface to receive the hatching cue (i.e., light and/or oxygen). In a comparative study of three sites in Oneida and Onondaga Lakes, NY, with differing sedimentation rates, we show that egg hatchability depends more upon egg age than on burial depth. When bioturbation depth is relatively constant among sites (as it is in Oneida Lake), however, sedimentation rate may be critical in determining the age distribution of eggs that hatch in nature. Pollution impacts alter these processes by affecting the survival of bioturbating benthos (in Onondaga Lake, an anoxic hypolimnion decimates the abundance of oligochaetes and chironomids), and the survival of buried eggs (in Onondaga Lake, sediment mercury and lead concentrations reach 80 mg and 300 mg per g dry sediment, respectively).