EVALUATION OF ABYSSAL METAZOAN MEIOFAUNA FROM A MANGANESE NODULE AREA OF THE EASTERN SOUTH PACIFIC

The metazoan meiofauna from a manganese nodule area of the eastern South Pacific (Peru Basin) was investigated. Nodule coverage in this area ranged from 5-30 % with many highly mammillated, botryoidal nodules exceeding 10 cm in diameter. Metazoan meiofaunal density in the sediment was about 147 id.! 10 cm(2). The predominant taxa in the sediment (excluding Foraminiferida) were Nematoda (82%) and Harpacticoida (15 %); other taxa occurred sporadically (3 %). While breaking-up some of the manganese nodules during an inspection for epifauna, a crevice fauna was discovered, living in the sediment-filled crevices and cracks between the mammillae. Metazoan meiofaunal density in the nodules was about 116 ind./nodule (diameter 8-12 cm) or 29 ind./10 cm(2) nodule plane, respectively. The predominant taxa in the nodules were Nematoda (89 %) and Harpacticoida (10 %); other taxa were very rare (1 %). Most of the nematode species (66 %) from this manganese nodule area possess minute buccal cavities without teeth; these nematodes are assumed to feed on bacteria and bacterial secretions. Many nematode species build sediment tubes and structure the uppermost sediment layer.