It is widely believed that during winter and spring, Arctic marine phytoplankton cannot grow until sea ice and snow cover start melting and transmit sufficient irradiance, but there is little observational evidence for that paradigm. To explore the life of phytoplankton during and after the polar night, we used robotic ice-avoiding profiling floats to measure ocean optics and phytoplankton characteristics continuously through two annual cycles in Baffin Bay, an Arctic sea that is covered by ice for 7 months a year. We demonstrate that net phytoplankton growth occurred even under 100% ice cover as early as February and that it resulted at least partly from photosynthesis. This highlights the adaptation of Arctic phytoplankton to extreme low-light conditions, which may be key to their survival before seeding the spring bloom.

人们普遍认为，在冬季和春季，北极海洋浮游植物要等到海冰和积雪开始融化并传输足够的辐照度后才能生长，但这种范式几乎没有观测证据。为了探索极夜期间和之后浮游植物的生命，我们使用机器人避冰剖面浮标在巴芬湾连续两个年度周期测量海洋光学和浮游植物特征，巴芬湾是一个每年被冰覆盖 7 个月的北极海. 我们证明，早在 2 月，即使在 100% 的冰盖下，浮游植物的净生长也发生了，并且至少部分是由光合作用引起的。这突出了北极浮游植物对极端弱光条件的适应，这可能是它们在春季开花之前生存的关键。