Climate change, diapause termination and zooplankton population dynamics: an experimental and modelling approach

Abstract

1. Earlier spring warming as predicted for climate change will alter combinations of water temperature and photoperiod that act as emergence cues for zooplankton resting stages. As a result, water temperature cue thresholds will be experienced at shorter photoperiods, a variable independent of weather variations. Also, light intensity, another potentially important cue for zooplankton emergence, could decrease in many lakes if symptoms of climate change resemble those of eutrophication. 2. We designed a laboratory experiment to test the effects of three factors, temperature (6, 9 and 12°C), photoperiod (13L : 11D and 16L : 8D) and light intensity (20 and 35 lE m )2 s )1 ) on hatchling abundance and timing of hatching of daphniids (Daphnia ambigua) and rotifers (Keratella spp. and Synchaeta pectinata) from resting eggs. Further, we investigated the implications of potential changes in hatching dynamics, following variations in hatching cues, on zooplankton spring population development using predator-prey simulation models. 3. For hatchling abundance and timing of hatching, photoperiod had a significant effect for D. ambigua but not rotifers. Daphnia ambigua hatchling abundance decreased by 50% when incubated at conditions mimicking early spring (12°C + 13-h photoperiod) compared to a later spring (12°C + 16-h photoperiod). Light intensity has a significant effect only for S. pectinata, producing greater hatchling abundance at lower light intensity. 4. Simulation models suggest that in contrast to a later spring, an early warming produces a shift in spring zooplankton community composition, from daphniid to rotifer dominance. These patterns are primarily driven by differential zooplankton emergence response with variations in temperature-photoperiod cues. 5. Overall, our laboratory experiments and simulation models suggest that lakes with strong dependence on the 'resting egg-bank', characteristic of many shallow northtemperate lakes or in years with low winter survivorship of adult zooplankton, may be most susceptible to climate change. Further, fewer large grazers such as daphniids with an earlier spring may result in less control of cyanobacterial blooms in eutrophic lakes.

Climate change and plankton phenology in freshwater: current trends and future commitments

“…Spring warming is likely to induce earlier emergence from resting stages (Chen and Folt, 2002; Gerten and Adrian, (Dupuis and Hann, 2009). Earlier ice-out was associated with increased hatchling abundance of Daphnia pulicaria in both the laboratory and in Oneida Lake (Cáceres and Schwalbach, 2001), suggesting a possibility to advance phenological events in this species.…”

“…Excellent examples are in Folt (2002), De Senerpont Domis et al (2007), Dupuis and Hann (2009). Hence, integrating the study of benthic-pelagic coupling into phenological research efforts will improve our understanding in the field.…”

Climate change and freshwater zooplankton: what does it boil down to?

“…Temperature and photoperiod are the major factors affecting emergence in zooplankton (Gyllström and Hansson 2004;Gilbert and Schröder 2004). Increased temperatures and shorter photoperiod have found to decrease Daphnia emergence from resting eggs while rotifers were less affected (Dupuis and Hann 2009b). Dupuis and Hann (2009b) argued that lakes with strong dependence on the egg bank, that is, low portion of overwintering individuals, are likely to fail to control algal growth because Daphnia hatching success decreases with climate change.…”

“…Increased temperatures and shorter photoperiod have found to decrease Daphnia emergence from resting eggs while rotifers were less affected (Dupuis and Hann 2009b). Dupuis and Hann (2009b) argued that lakes with strong dependence on the egg bank, that is, low portion of overwintering individuals, are likely to fail to control algal growth because Daphnia hatching success decreases with climate change. Different zooplankton species use different temperature-photoperiod cues; therefore, the outcome will vary with environmental forcing (Dupuis and Hann 2009b).…”

“…Dupuis and Hann (2009b) argued that lakes with strong dependence on the egg bank, that is, low portion of overwintering individuals, are likely to fail to control algal growth because Daphnia hatching success decreases with climate change. Different zooplankton species use different temperature-photoperiod cues; therefore, the outcome will vary with environmental forcing (Dupuis and Hann 2009b). Earlier ice-out was associated with increased hatchling abundance of Daphnia pulicaria in both the laboratory and in Oneida Lake (Cáceres and Schwalbach 2001), suggesting a possibility to advance phenological events in this species.…”