Diatoms are considered the main base of the Southern Ocean food web as they are responsible for more than 85% of its annual primary production and play a crucial role in the Antarctic trophic structure and in the biogeochemical cycles. Within this context, an intense diatom bloom reaching > 45 mg m⁻³ of chlorophyll a was registered in the Northern Antarctic Peninsula (NAP) during a late summer study in February 2016. Given that nutrient concentrations and grazing activities were not identified here as limiting factors on the bloom development, the aim of this study was to evaluate the effect of water column structure (stability and upper mixed layer depth) on the phytoplankton biomass and composition in the NAP. The diatom bloom, mainly composed by the large centric Odontella weissflogii (mostly > 70 μm in length), was associated with a local ocean carbon dioxide uptake that reached values greater than −60 mmol m⁻² d⁻¹. We hypothesize that the presence of a vertically large water column stability barrier, just below the pycnocline, was the main driver allowing for the development of the intense diatom bloom, particularly in the Gerlache Strait. Contrarily, a shift from diatoms to dinoflagellates (mainly Gymnodiniales < 20 μm) was observed associated with conditions of a highly stable thin layer. The results suggest that a large fraction of this intense diatom bloom is in fast sinking process, associated with low grazing pressure, showing a crucial role of diatoms for the efficiency of the biological carbon pump in this region.

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2016年2月，南极半岛北部硅藻大量繁殖的动力学

硅藻被认为是南部海洋食物网的主要基础，因为它们占其年度初级生产的85％以上，并且在南极营养结构和生物地球化学循环中起着至关重要的作用。在此背景下，激烈的硅藻水华达到> 45毫克间^-3叶绿素的一个是夏末的一个研究期间登记在北南极半岛（NAP）二月2016年由于营养浓度和放牧活动不在这里确定为限制影响水华形成的因素，本研究的目的是评估水柱结构（稳定性和上层混合层深度）对NAP中浮游植物生物量和组成的影响。硅藻绽放，主要由大的中心Odontella weissflogii（主要是> 70 μ在长度M）中，与本地海洋二氧化碳吸收该值达到比-60毫摩尔m的相关^-2 d ^-1。我们假设在比浓可可林的正下方有一个垂直的大水柱稳定性屏障，这是导致强烈的硅藻绽放的主要驱动力，特别是在Gerlache海峡。相反，从硅藻转变为鞭毛藻（主要是裸子藻< 20μm）被观察到与高度稳定的薄层的条件有关。结果表明，这种强烈的硅藻绽放的很大一部分处于快速下沉过程中，与较低的放牧压力相关，显示了硅藻对于该区域生物碳泵效率的关键作用。