Dormant egg banks play important roles in zooplankton community resilience and recovery. Resting eggs, like heavy metals, tend to accumulate, and their production can be a strategy to avoid pollutants. To test the hypothesis that pollutants can affect dormant populations, we exposed diapausing eggs of the freshwater rotifer Brachionus calyciflorus to 4 concentrations of copper (0.003, 0.03, 0.18 and 4 mg L^-1 of CuSO₄) and a control.  After hatching, one set of neonates from each treatment was placed in the control medium; and another set was re-exposed to the same concentration as the hatching treatment. Preliminary results showed a significantly higher proportion of failed hatching (5 - 30%) and post-hatching mortality (51 – 82%) in the 0.18 and 4 mg L^-1 treatments than in other treatments (> 2%), resulting in a lower percentage of viable offspring (<14%) at these concentrations. We also found that neonates from the control and the 0.003 mgL^-1 treatments had significantly longer lifespans (mean + SD: 13.5 + 5.2 days) and offspring per female (11.6 + 5.2 neonates) than the single exposure treatments (7.4 + 5 days; 5.5 + 4.4 neonates) and the re-exposure treatments (2.0 + 2.0 days; 1.0 + 1.0 neonate). These results suggest that at high concentrations copper can affect resting egg banks and the future performance of active populations, thereby negatively affecting zooplankton communities.

Primary Presenter: Alejandra Sanchez Avila, The University of Texas at El Paso (asanchezav@miners.utep.edu)

Authors:

Alejandra Sanchez Avila, The University of Texas at El Paso  (asanchezav@miners.utep.edu)

Andrea Salas Rivera, The University of Texas at El Paso  (asalas24@miners.utep.edu)

Elizabeth Walsh, The University of Texas at El Paso  (ewalsh@utep.edu)