Response of meiofauna to immediate benthic disturbance in the Central Indian Ocean Basin

Twenty-four stations (12 each, during pre- and postdisturbance studies) 5300 to 5330 m deep between 10 degrees 01' and 10 degrees 03'S lalialde and between 75 degrees 59' and 76 degrees 02'E longitude were sampled to study the effect of benthic disturbance oil the distribution of meiofauna in the Central Indian Ocean. Bottom-sampling was conducted with a box corer: Total,meiofauna density ranged from 35 to 45 organisms per 10 cm(2) of bottom area during rite predisturbance period and 21 to 32 organisms per 10 cm(2) during the postdisturbance period in the rest and reference sites. Differences between pre- and postdisturbance study results were statistically significant (P < 0.05). Nematoda was the most abundant metazoan group, on an average representing >55% of the meiofaunal population. The abundance of nematodes and harpacticoid copepods as well as total meiofauna showed marked decreases during postdisturbance sampling. Vertical distribution of meiofauna in the sediment cores revealed that 75% to 90% of the metazoan population was confined to the top 2-cm layer of the sediment. Recolonization experiments suggest that harpacticoid copepods may take more time for recolonization than the nematodes and ar-e more sensitive to the physical disturbance. These findings suggest that nematodes and harpacticoid copepods can be used as indicator organisms in recolonization experiments.