Lake Bonney (McMurdo Dry Valleys, east Antarctica) represents a year‐round refugium for life adapted to permanent extreme conditions. Despite intensive research since the 1960s, due to the logistical constraints posed by 4‐months of 24‐h darkness, knowledge of how the resident photosynthetic microorganisms respond to the polar winter is limited. In addition, the lake level has risen by more than 3 m since 2004: impacts of rapid lake level rise on phytoplankton community structure is also poorly understood. From 2004 to 2015 an in situ submersible spectrofluorometer (bbe FluoroProbe) was deployed in Lake Bonney during the austral summer to quantify the vertical structure of four functional algal groups (green algae, mixed algae, and cryptophytes, cyanobacteria). During the 2013–2014 field season the Fluoroprobe was mounted on autonomous cable‐crawling profilers deployed in both the east and west lobes of Lake Bonney, obtaining the first daily phytoplankton profiles through the polar night. Our findings showed that phytoplankton communities were differentially impacted by physical and chemical factors over long‐term versus seasonal time scales. Following a summer of rapid lake level rise (2010–2011), an increase in depth integrated chlorophyll a (chl‐a) occurred in Lake Bonney caused by stimulation of photoautotrophic green algae. Conversely, peaks in chl‐a during the polar night were associated with an increase in mixotrophic haptophytes and cryptophytes. Collectively our data reveal that phytoplankton groups possessing variable trophic abilities are differentially competitive during seasonal and long‐term time scales owing to periods of higher nutrients (photoautotrophs) versus light/energy limitation (mixotrophs).

中文翻译：

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永久性冰覆盖的南极湖邦尼湖的全年和长期浮游植物动态

邦尼湖（南极洲东部的麦克默多干旱谷）代表了一个终生避难所，适合永久的极端条件。尽管自1960年代以来进行了深入的研究，但由于4个月的24小时黑暗造成的后勤限制，关于常驻光合微生物如何应对极地冬季的知识仍然有限。此外，自2004年以来，湖泊水位上升了3 m以上：湖泊水位快速上升对浮游植物群落结构的影响也知之甚少。从2004年到2015年，在南方夏季期间，在邦尼湖部署了现场潜水式分光荧光计（bbe FluoroProbe），以量化四个功能藻类（绿藻，混合藻和隐藻，蓝藻）的垂直结构。在2013–2014野外季节，将荧光探针安装在部署在邦尼湖东，西两瓣的自动电缆爬行剖面仪上，直到极夜都获得了第一个每日浮游植物剖面图。我们的研究结果表明，在长期和季节性范围内，浮游植物群落受到物理和化学因素的差异影响。在夏季湖水位快速上升（2010-2011年）之后，由于光合自养绿藻的刺激，邦尼湖的综合叶绿素a（chl-a）深度增加。相反，极夜期间chl-a的峰值与混合营养的触附植物和隐生植物的增加有关。