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

The deep-sea floor is traditionally perceived as a habitat where low food flux and sluggish bottom currents force life to proceed at slow, steady rates. In this view, benthic community structure is controlled by equilibrium processes, such as extreme levels of habitat partitioning, made possible by remarkable ecosystem stability. A number of recent discoveries indicate, however, that endogenous disturbances may be relatively frequent, and that pulses of food reach the seafloor from the upper ocean. The biological processes driven by these events can be highly 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 building, 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 macrofaunal diversity and population structure, (2) deposit-feeder-microbe interactions and associated trace production, and (3) dispersal and biogeography of chemosynthetic communities at the deep-sea floor.