Spatial and temporal variability in nutrients and carbon uptake during 2004 and 2005 in theeastern equatorial Pacific Ocean

[摘要] The eastern equatorial Pacific plays a~great role in the global carbon budgetdue to its enhanced biological productivity linked to the equatorialupwelling. However, as confirmed by the Equatorial Biocomplexity cruises in2004 and 2005, nutrient upwelling supply varies strongly, partly due to thetropical instability waves (TIWs). The aim of this study was to examine patterns ofspatial and temporal variability in the biological uptake of NO₃,Si(OH)₄ and carbon in this region, and to evaluate the role ofbiological and physical interactions controlling this variability overseasonal and intraseasonal time scales. Here, high resolution PacificROMS–CoSiNE (Regional Ocean Modeling System–Carbon, Silicon, Nitrogen Ecosystem) model results were evaluated with in situ and remote sensingdata. The results of model–data comparison revealed a good agreement indomain-average hydrographic and biological rate estimates, and patterns ofspatio-temporal variability in primary productivity. We confirmed thatTIWs have the potential to enhance phytoplanktonbiomass through an increased supply of nutrients and elevated local andinstantaneous phytoplankton nutrient uptake as opposed to only advectingbiomass. Furthermore, we concluded that initial biological conditions(e.g., zooplankton biomass) may play an important additional constraint onbiological responses, in particular of large phytoplankton such as diatoms,to TIW-induced perturbations in the physical and biogeochemical fields andfluxes. In order to fully resolve the complexity of biological and physicalinteractions in the eastern equatorial Pacific, we recommended improvingCoSiNE and other models by introducing more phytoplankton groups, variableRedfield and carbon to chlorophyll ratios, as well as resolving the Fe–Sico-limitation of phytoplankton growth.

[学科分类] 地球化学与岩石