Spatial variation of ostracod (Crustacea, Ostracoda) egg banks in temporary lakes of a tropical flood plain

Abstract

Ostracods are microcrustaceans that produce resting eggs under adverse conditions. In this study we evaluated the spatial variation of ostracod resting eggs in different regions of temporary lakes in a Brazilian flood plain. Based on the homogenisation effect of flood pulses on aquatic communities in flood plains, we hypothesised that the composition and abundance of ostracod eggs in the centre of temporary lakes would be similar to those in edge regions. Samples were collected from the centre and edge regions of five temporary lakes. Sediment was oven dried, rehydrated and hatching was monitored in germinating chambers. Twelve ostracod species hatched from the egg banks during our experiments. The abundance and species composition were similar between the two regions of the lakes. Flood events may be responsible for the homogenisation of the egg banks as a result of the connection of lakes with principal river channels. During flooding, water masses powerfully enter lakes and can redistribute sediments. This study shows that egg banks have the potential to contribute to the maintenance of local biodiversity and the resilience of biodiversity of temporary lake ecosystems.