Mesoscale eddies cause deviations from the background physical and biogeochemical states of the oligotrophic oceans, but how these perturbations manifest in microbial ecosystem functioning, such as community macromolecular composition or carbon export, remains poorly characterized. We present comparative lipidomes from communities entrained in two eddies of opposite polarities (cyclone–anticyclone) in the North Pacific Subtropical Gyre (NPSG). A previous work on this two-eddy system has shown differences in particulate inorganic carbon (PIC) and biogenic silica sinking fluxes between the two eddies despite comparable total organic carbon fluxes. We measured the striking differences between the lipidomes of suspended and sinking particles that indicate taxon-specific responses to mesoscale perturbations. Specifically, cyanobacteria did not appear to respond to increased concentrations of phosphorus in the subsurface of the cyclonic eddy, while eukaryotic microbes exhibit P-stress relief as reflected in their lipid signatures. Furthermore, we found that two classes of lipids drive differences between suspended and sinking material: sinking particles are comparatively enriched in phosphatidylcholine (PC, a membrane-associated lipid) and triacylglycerol (TAG, an energy storage lipid). We observed significantly greater export of TAGs from the cyclonic eddy as compared to the anticyclone and found that this flux is strongly correlated with the concentration of ballast minerals (PIC and biogenic silica). This increased export of TAGs from the cyclone, but not the anticyclone, suggests that cyclonic eddy perturbations may be a mechanism for the delivery of energy-rich organic material below the euphotic zone.

中文翻译：

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脂质生化多样性和动力学揭示了北太平洋副热带环流中尺度涡流中浮游植物的营养胁迫反应和碳输出机制


中尺度涡流导致寡营养海洋的背景物理和生物地球化学状态发生偏差，但这些扰动如何在微生物生态系统功能（例如群落大分子组成或碳输出）中表现出来，仍然知之甚少。我们展示了北太平洋副热带环流（NPSG）中两个极性相反的涡流（气旋-反气旋）中夹带的群落的脂质组比较。先前对这个双涡流系统的研究表明，尽管总有机碳通量相当，但两个涡流之间的颗粒无机碳（PIC）和生物二氧化硅沉没通量存在差异。我们测量了悬浮颗粒和下沉颗粒的脂质组之间的显着差异，这表明分类单元对中尺度扰动的特异性反应。具体来说，蓝细菌似乎对气旋涡流表面下磷浓度的增加没有反应，而真核微生物则表现出 P-应力缓解，如其脂质特征所反映的那样。此外，我们发现两类脂质导致悬浮材料和下沉材料之间的差异：下沉颗粒相对富含磷脂酰胆碱（PC，一种膜相关脂质）和三酰甘油（TAG，一种能量储存脂质）。我们观察到，与反气旋相比，气旋涡流输出的 TAG 显着增加，并发现这种通量与压载矿物（PIC 和生物二氧化硅）的浓度密切相关。气旋而非反气旋的 TAG 输出增加，表明气旋涡流扰动可能是在富光带下方输送富含能量的有机物质的机制。