HR: 1350h
AN: U23C-1457    [Abstracts]
TI: Thirty Years of Continuous Particle Flux Observations in the Deep Sargasso Sea: Looking Back, Looking Forward
AU: * Conte, M H
EM: mconte@mbl.edu
AF: Bermuda Institute for Ocean Sciences, Ferry Reach, St Georges, GE01, Bermuda
AU: Weber, J C
EM: jweber@mbl.edu
AF: Ecosystems Center, MBL, Woods Hole, MA 02543, United States
AB: The Oceanic Flux Program sediment traps have continuously measured the deep ocean particle flux off Bermuda since the late 1970s, with a >95% temporal coverage at 3200m depth. The early OFP discovery of a seasonal cycle in deep particle flux clearly demonstrated that the deep ocean environment was directly coupled to overlying surface productivity via the particle flux, laying to rest the (then) widely held view of the abyssal ocean as an invariant, largely isolated environment. In the years since, time-series observations of the OFP and others have clearly shown that deep ocean environment is closely linked to upper ocean variability on time-scales of days to decades. The OFP record to date shows that in fact, the deep particle flux- analogous to atmospheric precipitation- follows a strongly skewed (gamma) frequency distribution with transient flux ""rainstorms"" occurring predominately in the late fall and spring periods when surface stratification is weak. On annual time-scales, particle flux is negatively correlated with the wintertime (NDJF) NAO Index. This correlation reflects the greater frequency of transient, high flux events in years when the wintertime NAO Index is low, suggesting a direct influence of increased wintertime storminess. Many causal linkages identified between variability in deep flux and upper ocean forcing off Bermuda have been made possible because of the co-location of two other, complementary observational programs near the OFP mooring: BATS, a ship-based time-series established in 1988 that collects monthly data on upper ocean biogeochemical parameters, and the Bermuda Testbed Mooring (BTM), a platform for moored instrumentation that since 1994 has generated near-continuous data streams on meteorological, physical and bio-optical parameters. In turn, the OFP deep flux record has provided an essential reference point that enables direct evaluation of the biogeochemical consequences of the upper ocean variability observed by BATS and BTM; for example, the influence of mesoscale features that pass through the area. Deep moored sediment traps are a simple, proven and relatively inexpensive technology that provide a unique, spatially integrated, continuous record of the overlying environment. Advances in analytical methods are rapidly expanding our ability to extract ever more detailed oceanographic information from the recovered flux material. As such, deep sediment traps are an invaluable observational component for long-term global ocean observatory networks.
DE: 4215 Climate and interannual variability (1616, 1635, 3305, 3309, 4513)
DE: 4262 Ocean observing systems
DE: 4263 Ocean predictability and prediction (3238)
DE: 4277 Time series experiments (1872, 3270, 4475)
DE: 4806 Carbon cycling (0428)
SC: Union [U]
MN: 2007 Fall Meeting