Interactions between ultraviolet radiation exposure and phosphorus limitation in the marine nitrogen‐fixing cyanobacteria Trichodesmium and Crocosphaera
Interactions between ultraviolet radiation exposure and phosphorus limitation in the marine nitrogen‐fixing cyanobacteria Trichodesmium and Crocosphaera
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DOI：
10.1002/lno.11304
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发表时间：
2019-08
影响因子：
4.5
通讯作者：
Zhu Zhu-Zhu;Feixue Fu;Ping-Ping Qu-Ping;E. W. M. Mak;Hai-Bo Jiang;Ruifeng Zhang;Zhuoyi Zhu;K. Gao
中科院分区：
文献类型：
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作者：
Zhu Zhu-Zhu;Feixue Fu;Ping-Ping Qu-Ping;E. W. M. Mak;Hai-Bo Jiang;Ruifeng Zhang;Zhuoyi Zhu;K. Gao
由于变暖而导致的海洋表层分层和混合层变浅的增加可能导致海洋固氮蓝藻暴露于更高水平的抑制性紫外线（UV）辐射。这些相同的过程也减少了垂直平流供应的潜在限制营养磷（P）的氮固定。目前尚不清楚UV抑制和P限制如何相互作用以影响这些生态地球化学关键微生物中的氮和碳的生态地球化学循环。我们研究了重要和广泛的海洋固氮蓝藻Crocosphaera（菌株WH 0005）和Trichodesmium（菌株IMS 101和GBR）在P-充分和P-限制条件下对UV-A和UV-B的响应。生长，N2固定，和二氧化碳（CO2）固定率的束毛孢IMS 101和Crocosphaera的紫外线照射产生负面影响。这种抑制作用对束毛藻IMS 101的影响大于对Crocosphaera的影响，Crocosphaera仅在夜间固定N2，因此避免了直接的UV损伤。在P-限制培养物中，UV对IMS 101和Crocosphaera的负面影响小于P-充满培养物。与此相反，没有UV抑制GBR中观察到，无论P的可用性。UV抑制与这些分离株产生的UV吸收化合物的量不同有关。对UV辐射和P有效性相互作用的反应是分类特异性的，但我们的研究结果表明，一般来说，UV辐射对束毛藻和Crocosphaera的影响范围从负面到中性。因此，紫外线抑制及其与磷限制的相互作用可能对当今和未来海洋的氮和碳循环产生重大影响。
Increased stratification and mixed layer shoaling of the surface ocean resulting from warming can lead to exposure of marine dinitrogen (N2)‐fixing cyanobacteria to higher levels of inhibitory ultraviolet (UV) radiation. These same processes also reduce vertically advected supplies of the potentially limiting nutrient phosphorus (P) to N2 fixers. It is currently unknown how UV inhibition and P limitation interact to affect the biogeochemical cycles of nitrogen and carbon in these biogeochemically critical microbes. We investigated the responses of the important and widespread marine N2‐fixing cyanobacteria Crocosphaera (strain WH0005) and Trichodesmium (strains IMS 101 and GBR) to UV‐A and UV‐B under P‐replete and P‐limited conditions. Growth, N2 fixation, and carbon dioxide (CO2) fixation rates of Trichodesmium IMS 101 and Crocosphaera were negatively affected by UV exposure. This inhibition was greater for Trichodesmium IMS 101 than for Crocosphaera, which fixes N2 only during the night and so avoids direct UV damage. Negative effects of UV on both IMS 101 and Crocosphaera were less in P‐limited cultures than in P‐replete cultures. In contrast, no UV inhibition was observed in GBR, regardless of P availability. UV inhibition was related to different amounts of UV‐absorbing compounds produced by these isolates. Responses to UV radiation and P availability interactions were taxon‐specific, but our results indicated that in general, UV radiation effects on Trichodesmium and Crocosphaera range from negative to neutral. UV inhibition and its interactions with P limitation may thus have a substantial influence on the present day and future nitrogen and carbon cycles of the ocean.