Two decades and counting: 24-years of sustained open ocean biogeochemical measurements in the Sargasso Sea

摘要: The Bermuda Atlantic Time-series Study (BATS) program has sampled the northwestern Sargasso Sea on a biweekly (January to April) monthly basis since October 1988. primary objective of core BATS continues be an improved understanding time-variable processes and mechanisms that control biogeochemical cycling carbon related elements in surface ocean. With 24 years measurements for most chemical, physical biological variables, we have moved beyond descriptions seasonal interannual variability examination multi-year trends potential controls, however there remain substantial gaps our knowledge ecosystem organic matter production, export remineralization. While earlier overviews focused describing year-to-year variability, this overview provides new information three long-standing questions biogeochemistry. First, why is discrepancy between (i.e., sediment trap) geochemical estimates production? Winter storms mesoscale eddies now been clearly shown contribute annual nutrient budgets production. Recent phytoplankton natural isotopic nitrogen composition, data from profiling floats suggests small are important contributors production summer despite apparent absence mechanism entrain nitrate into euphotic zone. These findings aid closing gap these two different Second, what supports drawdown dioxide detectable nutrients? zooplankton timeseries at highlights importance as conduit removal due grazing vertical migration. Although increases cellular elemental stoichiometry values greater than canonical Redfield Ratio, (and interannual) accumulation zone dissolved (DOC) without DON ocean also explanations. Lastly, sources elevated phosphate ratio thermocline (N:P>30 average)? generally accepted fixation source additional nitrogen, research remineralization non-diazotroph particulate enriched (alternatively viewed depleted phosphorus) may make contributions. In addition, phosphorus captured traps decreased 50–75 <50, possibly enhanced other observational cycles subtropical North Ocean how they changing over time.