OVERVIEW OF THE US JGOFS BERMUDA ATLANTIC TIME-SERIES STUDY AND THE HYDROSTATION S PROGRAM

In October 1988 the Bermuda Atlantic Time-series Study (BATS) commence d sampling the Sargasso Sea in an area 85 km south-east of Bermuda as part of the U.S. Joint Global Ocean Flux Study (JGOFS). The scientific goal of the BATS program is to understand the causes of seasonal and interannual variability in ocean biogeochemistry both at this site and as it may relate to biogeochemistry of the rest of the ocean. Bermuda is also the site of other continuing and historical oceanic and atmos pheric time-series programs. The ongoing Hydrostation S time-series co mmenced in 1954 and the biweekly profiles of temperature, salinity and oxygen provide data to link the more recent biogeochemistry time-seri es studies to the decadal variability in this region. Data on midwater particle fluxes have been collected continuously since 1976, ongoing measurements of atmospheric chemistry and wet and dry deposition began in 1980 and a long-term study of benthic boundary fluxes began in 198 6. These various time-series studies complement each other and combine to make this region one of the most heavily documented oceanic enviro nments in the world. The BATS and Hydrostation S programs each sample the ocean on a biweekly-to-monthly basis, a strategy that resolves the major seasonal patterns, interannual variability and decadal patterns . The Sargasso Sea also has more episodic or local processes, such as fluctuations that occur on scales of days to weeks and mesoscale eddie s, and potentially patterns from the net advection of water past the s ampling sites; these processes are more difficult to resolve by the on e-dimensional time-series sampling strategy. The BATS program has begu n to provide a coherent picture of the oceanic carbon and nutrient cyc les in this region and the linkage between these cycles and the biolog ical, chemical, physical and optical processes that control them. The significant interannual and decadal variability in the physical enviro nment near Bermuda also allows us to examine the longer-term relations hips between the physical forcing and biogeochemical response. Finally , the BATS program has proved a valuable platform to support other anc illary oceanographic research and technology development. These studie s all benefit from the existence of the core time-series studies to ad d context and value to their more specific research efforts and they, in turn, further enhance the diversity of co-located measurements in t his area. Copyright (C) 1996 Elsevier Science Ltd