Nutrient transfer into the sunlit surface ocean by cyclonic eddies is potentially crucial for sustaining primary productivity in the stratified subtropical gyres. However, the nature of productivity enhancements, including the flow of matter to higher trophic levels and its impact on carbon fluxes, remain poorly resolved. Here, we report a detailed assessment of the biogeochemical response to a cyclonic eddy in the subtropical Northwest Pacific via a combination of ship‐based and autonomous platforms. Primary production was enhanced twofold within the eddy core relative to reference sites outside, whereas phytoplankton biomass even decreased. Pico‐phytoplankton (< 2 μm) dominated (> 80%) both phytoplankton biomass and primary production inside and outside the eddy. The stimulated primary production in the eddy core was accompanied by an approximately twofold increase in mesozooplankton abundance, an approximately threefold increase in particle formation in the deep chlorophyll maximum layer, as well as significantly enhanced surface oceanic CO2 uptake and net community production. We suggest these observations carry important implications for understanding carbon export in the subtropical ocean and highlight the need to include such subtropical eddy features in ocean carbon budget analyses.

中文翻译：

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小型浮游植物的刺激促进了亚热带海洋涡流中下沉颗粒的形成

通过气旋涡流将营养物质转移到阳光照射的表层海洋对于维持层状副热带环流的初级生产力可能至关重要。然而，生产力提高的本质，包括物质向更高营养级的流动及其对碳通量的影响，仍然没有得到很好的解决。在这里，我们报告了通过船基和自主平台相结合对副热带西北太平洋气旋涡旋的生物地球化学响应的详细评估。相对于外部参考点，涡流核心内的初级生产力增加了一倍，而浮游植物生物量甚至减少。微型浮游植物 (< 2μm) 主导 (> 80%) 涡流内外的浮游植物生物量和初级生产。涡流核心的初级生产受到刺激，中型浮游动物丰度增加约两倍，叶绿素最大层深处的颗粒形成增加约三倍，以及表层海洋二氧化碳显着增加。2吸收和净社区生产。我们认为这些观测结果对于理解副热带海洋的碳输出具有重要意义，并强调需要在海洋碳预算分析中纳入此类副热带涡流特征。