作者: Michael R. Stukel , Claudia R. Benitez-Nelson , Moira Décima , Andrew G. Taylor , Carolyn Buchwald
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摘要: The Costa Rica Dome is a picophytoplankton-dominated, open-ocean upwelling system in the Eastern Tropical Pacific that overlies ocean's largest oxygen minimum zone. To investigate efficiency of biological pump this unique area, we used shallow (90-150 m) drifting sediment traps and 234Th:238U deficiency measurements to determine export fluxes carbon, nitrogen phosphorus sinking particles. Simultaneous nitrate uptake water nitrification allowed us assess equilibrium balance new production over monthly timescale. While f-ratios (new:total production) were reasonably high (0.36 ± 0.12, mean standard deviation), efficiencies considerably lower. Sediment suggested e-ratios (export/14C-primary at 90-100 m ranging from 0.053 0.067. ThE-ratios (234Th disequilibrium-derived export) ranged 0.038 0.088. C:N N:P stoichiometries material both greater than canonical (Redfield) ratios or measured suspended particulates, they increased with depth, suggesting preferentially remineralized Our results are consistent an ecosystem which mesozooplankton play major role energy transfer higher trophic levels but relatively inefficient mediating vertical carbon flux leading imbalance between flux.