Pseudo-diel vertical migration in zooplankton: a whole-lake 15N tracer experiment (original) (raw)

Diel vertical migration (DVM) of zooplankton is examined in a Spanish karst lake, focusing on discrepancies between predicted patterns and observed behaviors. The research utilized stable nitrogen isotopes (15N) to trace movement, revealing that cladoceran Diaphanosoma brachyurum exhibited a significant increase in biomass in the epilimnion at night, without a corresponding decrease in deeper waters. Contrary to traditional notions of DVM, findings suggest that horizontal movements rather than vertical migration account for the observed abundance in the epilimnion, indicating a lack of food incentives for DVM in this context.