Anomalously high abundance of Crocosphaera in the South Pacific Gyre
Anomalously high abundance of Crocosphaera in the South Pacific Gyre
复制标题
南太平洋环流中鳄鱼数量异常丰富
DOI：
10.1093/femsle/fnac039
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发表时间：
2022
影响因子：
2.1
通讯作者：
Bonnet, Sophie
中科院分区：
文献类型：
--
作者：
Benavides, Mar;Caffin, Mathieu;Duhamel, Solange;Foster, Rachel Ann;Grosso, Olivier;Guieu, Cécile;Van Wambeke, France;Bonnet, Sophie
单细胞重氮蓝藻Crocosphaera对贫营养海洋中的固定氮输入有显著贡献。在西热带南太平洋（WTSP），这些固氮生物丰富，这要归功于南赤道流提供的富磷沃茨，以及风成和地下火山活动提供的铁。在WTSP以东，南太平洋环流（SPG）拥有世界上最贫营养和最透明的沃茨，以前只有异养重氮生物被报道过。在SPG中，我们在50 m处检测到了Crocosphaera的意外积累，峰值丰度为5.26 × 105 nifH基因拷贝数l-1。50 m处的Crocosphaera丰度与WTSP中向西检测到的数量级相同，代表了100%的体积N2固定率。在50 m处的这种积累可能是由于SPG的清澈沃茨中紫外线的更深渗透对Crocosphaeragrogrowth和N2固定活性有害。营养和微量金属添加实验没有引起任何显着的变化N2固定或Crocosphaera丰度，表明这个人口是不受资源测试，尽管贫营养条件下，可以发展在高的数字。我们的研究结果表明，Crocosphaeracan的分布延伸到副热带涡旋和进一步了解其控制因素是必要的。
The unicellular diazotrophic cyanobacteriumCrocosphaeracontributes significantly to fixed nitrogen inputs in the oligotrophic ocean. In the western tropical South Pacific Ocean (WTSP), these diazotrophs abound thanks to the phosphorus-rich waters provided by the South Equatorial Current, and iron provided aeolian and subsurface volcanic activity. East of the WTSP, the South Pacific Gyre (SPG) harbors the most oligotrophic and transparent waters of the world's oceans, where only heterotrophic diazotrophs have been reported before. Here, in the SPG, we detected unexpected accumulation ofCrocosphaeraat 50 m with peak abundances of 5.26 × 105nifHgene copies l–1. The abundance ofCrocosphaeraat 50 m was in the same order of magnitude as those detected westwards in the WTSP and represented 100% of volumetric N2fixation rates. This accumulation at 50 m was likely due to a deeper penetration of UV light in the clear waters of the SPG being detrimental forCrocosphaeragrowth and N2fixation activity. Nutrient and trace metal addition experiments did not induce any significant changes in N2fixation orCrocosphaeraabundance, indicating that this population was not limited by the resources tested and could develop in high numbers despite the oligotrophic conditions. Our findings indicate that the distribution ofCrocosphaeracan extend into subtropical gyres and further understanding of their controlling factors is needed.