A HELD EXPERIMENT ON THE EFFECT OF 2 TYPES OF SEDIMENT DISTURBANCE ONTHE RATE OF RECOVERY OF A MEIOBENTHIC COMMUNITY IN A EUTROPHICATED LAGOON

A recolonization field experiment of two different artificially distur bed sediments (both defaunated sand and defaunated/reduced sand throug h organic enrichment) was carried out in the Sacca di Gore (Adriatic s ea, Po river Delta, Italy). Copepods showed themselves better colonize rs than nematodes. In particular, copepods, in the defaunated sand, we re able to reach the same densities as the control site after only sev en days from the beginning of the experiment. In the reduced-sand, cop epod recolonization occurred more slowly but reached the densities fou nd in both azoic and control sediments at the end of the experiment (1 5 days), when the values of total carbon content decreased. The recove ry evolution of the community structures was mostly dependent on the d ifferent behaviour of the active epibenthic species of the harpacticoi ds (e.g. Canuella perplexa T. & A. Scott, 1893, Ameira parvula (Claus, 1866), Robertgurneya similis (A. Scott, 1896)) and of the passively t ransported endobenthic ones (e.g. Asellopsis sarmatica Jakubisiak, 193 8, Ectinosoma dentatum Steuer, 1940).