Long time-series studies have extensively altered our basic understanding of biological processes in the deep ocean. We have established a long time-series station at an abyssal site in the eastern N. Pacific (4100 m depth) and, over the past three years, have been measuring particulate matter flux while concurrently monitoring the sea floor with time-lapse photography. We have found a strong temporal relationship between the flux of particulate matter entering the benthic boundary layer and the arrival and residence of detrital aggregates on the sea floor. The residence of these detrital aggregates spans a six-month period and coincides with increased abundance and movements of the epibenthic megafauna. Our results to date suggest coupling exists between near-bottom pelagic and benthic processes. However, the most important questions still remain regarding how and on what time scales the pelagic and benthic processes are coupled in the deep sea, especially in the context of the interannual variability we have observed over the past three years. We propose to study the coupling between the pelagic supply of organic matter and its utilization by the benthic community using in situ measurements of detrital aggregates superimposed on a continuing time-series study of monitoring the benthic boundary layer. Specifically, we propose to address three questions. 1) What is the source of detrital aggregates observed seasonally on the sea floor? 2) How important are detrital aggregates as sites of sediment community activity? 3) How important are detrital aggregates as sited of epibenthic megafaunal activity? This study will improve our understanding of the coupling between pelagic and benthic processes and broaden current perceptions of biogeochemical cycling over interannual time scales in the deep ocean.
