TEMPO AND MODE IN DEEP-SEA BENTHIC ECOLOGY - PUNCTUATED EQUILIBRIUM REVISITED

The deep-sea floor is traditionally perceived as a habitat where low f ood flux and sluggish bottom currents force life to proceed at slow, s teady rates. In this view, benthic community structure is controlled b y equilibrium processes, such as extreme levels of habitat partitionin g, made possible by remarkable ecosystem stability. A number of recent discoveries indicate, however, that endogenous disturbances may be re latively frequent, and that pulses of food reach the seafloor from the upper ocean. The biological processes driven by these events can be h ighly variable in space and time, exhibiting disequilibrium dynamics. I briefly review four examples of pulsed events that ''punctuate'' the apparent ''equilibrium'' of the deep-sea floor: biogenic mound buildi ng, benthic ''storms,'' pulses of phytodetritus, and whale falls. Such punctuational events may substantially influence processes of modern and past ecological significance, including (1) maintenance of macrofa unal diversity and population structure, (2) deposit-feeder-microbe in teractions and associated trace production, and (3) dispersal and biog eography of chemosynthetic communities at the deep-sea floor.