BATHYMETRIC PATTERNS OF POLYCHAETE DIVERSITY IN THE ROCKALL-TROUGH, NORTHEAST ATLANTIC

Polychaete diversity patterns were analyzed in spade box core samples down a transect from the Hebridean Slope to the floor of the Rockall T rough. Three sets of samples were analyzed: upper slope (400-1062 m), mid to lower slope (1000-1800 m) and the floor of the Trough (2900 m). Polychaete species' richness showed a parabolic distribution, peaking at about 1800 m. Investigation of potential structuring processes ind icated that disturbance, in the form of the frequency of high energy c urrents and intrataxocene predation, was important on the Hebridean Sl ope. On the floor of the Trough the high variation of neutral model re sults among samples suggested that localized, patch dynamics were more important.