Conte¹, M.H., J.C. Weber¹, T.D. Dickey², R.J. Johnson³ and A.H. Knap³

¹Dept. of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole MA 02543, E-mail: mconte@whoi.edu, ²University of California, Santa Barbara, 6487 Calle Real Unit A, Santa Barbara CA 93117 and ³Bermuda Biological Station for Research, Inc., Ferry Reach, St. Georges GE01, Bermuda

Surface - deep ocean linkages via particle flux at the Bermuda Time-series site

The Oceanic Flux Program (OFP) sediment trap time-series, now 25 years strong, is the longest time-series of its kind. The OFP time series exhibits variability in flux to the deep ocean on time scales ranging from weeks to decades, and shows a close connection between deep flux and upper ocean processes. With the establishment of upper ocean time series near the OFP site- the Bermuda-Atlantic Time-series (BATS) in 1988 and the Bermuda Testbed Mooring (BTM) in 1994- we now have an unparalleled opportunity to directly assess causal processes that couple the surface and the deep ocean environments. Accumulating evidence indicates that many of the episodic flux "events" observed throughout the OFP record are caused by short-lived blooms (e.g., salp blooms) and transient perturbations of mixed layer dynamics and biology that are associated with the passage of mesoscale features. These episodic flux events appear to greatly enhance the transfer of labile biogenic material to the deep ocean, and may exert a primary control on the mean export of bioreactive materials to waters deeper than the depth of wintertime mixing. The apparent linkage of these events with high-frequency temporal and mesoscale forcing further suggests that flux patterns may be extremely sensitive to change in the variability of the climate-ocean system, as well as to change in its mean state. Longer records are needed to fully reveal the details of coupled interactions among upper ocean physics, biology and chemistry and flux patterns, and how these in turn are linked to climatic forcing.