SS4.05 Tribute to Thomas Frost
Date: Monday, June 10, 2002
Time: 11:15:00 AM
Location: Sidney
 
FischerJM, Franklin & Marshall College, Lancaster, USA, j_fischer@fandm.edu
Yoder, K, E, Franklin & Marshall College, Lancaster, USA, keyoder75@aol.com
Stum, W, A, Franklin & Marshall College, Lancaster, USA, wa_stum@fandm.edu
 
CHANGES IN ACID SENSITIVITY OF DIAPTOMUS MINUTUS DURING ACIDIFICATION AND RECOVERY OF LITTLE ROCK LAKE, WI: A HISTORICAL RECONSTRUCTION USING DIAPAUSING EGGS
image
The effects of rapid evolutionary responses are frequently ignored in attempts to predict ecological responses to environmental change. In this study, we examined changes in acid sensitivity of the copepod Diaptomus minutus during experimental acidification and recovery of Little Rock Lake, WI. We used Diaptomus minutus diapausing eggs from sediment cores to reconstruct patterns of acid sensitivity during the last two decades. Sediment cores were sliced such that pre-acidification, peak acidification, and post acidification time periods were contained in separate slices. To test acid sensitivity of individuals from each time period, we hatched and raised nauplii to the first copepodite stage under favorable conditions (high pH, unlimited food) and then measured time to starvation at either high or low pH following standard bioassay protocols. Individuals from peak acidification were more acid tolerant than individuals from pre-acidification. Our results suggest that evolutionary responses may play an important role in population responses to environmental perturbations. In this case, adaption increased acid tolerance of Diaptomus minutus.