A field experiment on the effect of two types of sediment disturbance on the rate of recovery of a meiobenthic community in a eutrophicated lagoon

A recolonization field experiment of two different artificially disturbed sediments (both defaunated sand and defaunated/reduced sand through organic enrichment) was carried out in the Sacca di Goro (Adriatic sea, Po river Delta, Italy). Copepods showed themselves better colonizers than nematodes. In particular, copepods, in the defaunated sand, were able to reach the same densities as the control site after only seven days from the beginning of the experiment. In the reduced-sand, copepod recolonization occurred more slowly but reached the densities found in both azoic and control sediments at the end of the experiment (15 days), when the values of total carbon content decreased. The recovery evolution of the community structures was mostly dependent on the different behaviour of the active epibenthic species of the harpacticoids (e.g. Canuella perplexa T & A. Scott, 1893, Ameira parvula (Claus, 1866), Robertgurneya similis (A. Scott, 1896)) and of the passively transported endobenthic ones (e.g. Asellopsis sarmatica Jakubisiak, 1938, Ectinosoma dentatum Steuer, 1940).