Norwegian Polar Institute, Tromsø, Norway.
NTNU, Trondheim University, Trondheim, Norway.
Nat Commun. 2023 Mar 9;14(1):1303. doi: 10.1038/s41467-023-36992-1.
The Southern Ocean is a major sink of anthropogenic CO and an important foraging area for top trophic level consumers. However, iron limitation sets an upper limit to primary productivity. Here we report on a considerably dense late summer phytoplankton bloom spanning 9000 km in the open ocean of the eastern Weddell Gyre. Over its 2.5 months duration, the bloom accumulated up to 20 g C m of organic matter, which is unusually high for Southern Ocean open waters. We show that, over 1997-2019, this open ocean bloom was likely driven by anomalies in easterly winds that push sea ice southwards and favor the upwelling of Warm Deep Water enriched in hydrothermal iron and, possibly, other iron sources. This recurring open ocean bloom likely facilitates enhanced carbon export and sustains high standing stocks of Antarctic krill, supporting feeding hot spots for marine birds and baleen whales.
南大洋是人为 CO 的主要汇和顶级营养级消费者的重要觅食区。然而，铁限制设定了初级生产力的上限。在这里，我们报告了在威德尔环流东部开阔海域发生的一次相当密集的夏末浮游植物大量繁殖，跨度达 9000 公里。在其 2.5 个月的时间里，该繁殖期积累了高达 20 克 C m 的有机物质，这对于南大洋开阔水域来说非常高。我们表明，在 1997 年至 2019 年期间，这种开阔海域的繁殖可能是由东风异常引起的，东风将海冰推向南方，并有利于富含水热铁和可能其他铁源的温暖深海上升流。这种反复出现的开阔海域繁殖可能有利于增强碳输出，并维持南极磷虾的高现存量，为海洋鸟类和须鲸提供觅食热点。
