Recovery of macrobenthos in defaunated tropical estuarine sediments

► Recolonization and recovery time of macrobenthos after defaunation were analyzed. ► We simulate hypoxia/anoxia by a manipulative mesoscale field experiment. ► The rapidity of benthic community recovery was inversely proportional to the sampling depth. ► The recovery of the defaunated area was reached in 5 months based on species dependent (multivariate) analysis. In the estuarine environment, hypoxia and/or anoxia have become a major cause of benthic defaunation and are strongly associated with increased eutrophication. Mesoscale field experiments were carried out to examine the recolonization and recovery time of macrobenthos after defaunation. Azoic sediments were achieved by covering four areas with polyethylene sheeting. Temporal changes and depth distribution of macrobenthos within the defaunated sediments were compared with those in undisturbed natural sediments at the same site. Within 3days, annelids appeared as the first immigrants. After 153days, the process of recovery had not yet been completed in terms of species richness. Whereas diversity and evenness showed no significant differences between treatments during the entire experiment, multivariate analyses proved that differences between treatments were still significant 93days after the start of the experiment.