The Barents Sea is considered a warming hotspot in the Arctic; elevated sea surface temperatures have been accompanied with increased inflow of Atlantic water onto the shelf sea. Such hydrodynamic changes and a concomitant reduction of sea ice coverage enables a prolonged phytoplankton growing season, which will inevitably affect nutrient stoichiometry and the controls on primary production. During the summer of 2018, we investigated the role of phosphorus in mediating primary production in the Barents Sea. Dissolved inorganic phosphorus (DIP), its most bioavailable form, had an average net turnover time of 9.4 ± 4.8 d. The most southern Atlantic influenced station accounted for both the highest rates of primary production (655 mg C m² d⁻¹) and shortest net DIP turnover (2.8 ± 0.5 d). The fraction of assimilated DIP released as dissolved organic phosphorus (DOP) at this station was < 4% compared to an average of 21% at all other stations. We observed significant differences between phytoplankton communities in Arctic and Atlantic waters within the Barents Sea. Slower DIP turnover and greater release of DOP was associated with Phaeocystis pouchetii dominated communities in Arctic waters. Faster turnover rates and greater phosphorus retention occurred among the Atlantic phytoplankton communities dominated by Emiliania huxleyi. These findings provide baseline measurements of P utilization in the Barents Sea, and suggest increased Atlantic intrusion of this region could be accompanied by more rapid DIP turnover, possibly leading to future P limitation (rather than N limitation) on primary production.

中文翻译：

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巴伦支海的磷动力学

巴伦支海被认为是北极变暖的热点。海平面温度升高伴随着大西洋水向陆架海的流入量增加。这种流体力学的变化以及随之而来的海冰覆盖面积的减少使得浮游植物的生长期得以延长，这将不可避免地影响营养物的化学计量以及对初级生产的控制。在2018年夏季，我们调查了磷在调解巴伦支海初级生产中的作用。溶解无机磷（DIP）是生物利用度最高的形式，其平均净周转时间为9.4±4.8 d。受大西洋影响最南部的台站是一次生产力最高的地区（655 mg C m ² d ^-1）和最短的DIP净周转率（2.8±0.5 d）。在该站中，以溶解有机磷（DOP）形式释放的同化DIP比例<4％，而其他所有站的平均值为21％。我们在巴伦支海的北极和大西洋水域观察到浮游植物群落之间的显着差异。DIP转换速度减慢和DOP释放更多与北极水域以Phaeocystis pouchetii为主的群落有关。在以Emiliaania huxleyi为主的大西洋浮游植物群落中发生了更快的周转率和更大的磷滞留。这些发现提供了巴伦支海磷利用的基线测量，并表明大西洋入侵对该地区的增加可能伴随着更快速的DIP周转，这可能导致初级生产中未来的磷限制（而非氮限制）。