Molecular underpinnings and biogeochemical consequences of enhanced diatom growth in a warming Southern Ocean.
Molecular underpinnings and biogeochemical consequences of enhanced diatom growth in a warming Southern Ocean.
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DOI：
10.1073/pnas.2107238118
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发表时间：
2021-07-27
影响因子：
11.1
通讯作者：
Bertrand EM
中科院分区：
文献类型：
--
作者：
Jabre LJ;Allen AE;McCain JSP;McCrow JP;Tenenbaum N;Spackeen JL;Sipler RE;Green BR;Bronk DA;Hutchins DA;Bertrand EM
浮游植物有助于南大洋（SO）吸收大气CO2的能力，并形成向北输送大量营养素的化学计量。气候变化正在改变SO环境，但我们对浮游植物如何应对这些变化知之甚少。在这里，我们研究了一个自然的SO社区，并比较了两个流行的，水华形成硅藻群的温度和铁的变化，预计将发生在2100年至2300年的反应。我们发现，一组，伪菱形藻，生长更好地在温暖的低铁条件下，通过管理细胞铁的需求和有效地提高光合能力。这种在气候变暖的情况下生长和吸收养分的能力，无论铁的可用性如何，对海洋生态系统和全球养分循环具有重大影响。南大洋（SO）拥有地球上最强烈的浮游植物水华。温度和铁的可用性的变化，预计将改变SO浮游植物水华的强度，但鲜为人知的是，这些变化将如何影响社区组成和下游生态地球化学过程。我们对罗斯海麦克默多海峡的表层海洋微生物群落进行了光饱和实验操作，以研究铁可用性增加（+2 nM）和变暖（+3和+6 °C）对营养吸收的影响，以及两种优势硅藻（拟脆藻和伪菱形藻）的生长和转录反应。我们发现，在没有铁添加的两种变暖条件下（相对于环境-0.5 °C），群落养分吸收和初级生产力都有所提高。在同时添加铁和加热的情况下，这种效果比添加剂更大。假菱形藻在不添加铁的情况下（特别是在6 °C下）在变暖下变得更加丰富，而脆裂藻在添加铁的处理中只在变暖下变得更加丰富。我们属性的明显优势Pseudo-nitzschia显示在变暖下上调的铁保存光合作用过程，利用铁经济的氮同化机制，增加铁的吸收和储存。这些数据确定了主要硅藻群之间重要的分子和生理差异，并为伪菱形藻在变暖SO生态系统中日益重要的作用提供了越来越多的证据。这项研究还表明，在SO浮游植物组合的温度驱动的变化可能会增加利用铁有限的SO表面沃茨，从而影响全球营养盐分布和碳循环的大量过剩的营养盐。
Phytoplankton contribute to the Southern Ocean’s (SO) ability to absorb atmospheric CO2 and shape the stoichiometry of northward macronutrient delivery. Climate change is altering the SO environment, yet we know little about how resident phytoplankton will react to these changes. Here, we studied a natural SO community and compared responses of two prevalent, bloom-forming diatom groups to changes in temperature and iron that are projected to occur by 2100 to 2300. We found that one group, Pseudo-nitzschia, grows better under warmer low-iron conditions by managing cellular iron demand and efficiently increasing photosynthetic capacity. This ability to grow and draw down nutrients in the face of warming, regardless of iron availability, has major implications for ocean ecosystems and global nutrient cycles. The Southern Ocean (SO) harbors some of the most intense phytoplankton blooms on Earth. Changes in temperature and iron availability are expected to alter the intensity of SO phytoplankton blooms, but little is known about how these changes will influence community composition and downstream biogeochemical processes. We performed light-saturated experimental manipulations on surface ocean microbial communities from McMurdo Sound in the Ross Sea to examine the effects of increased iron availability (+2 nM) and warming (+3 and +6 °C) on nutrient uptake, as well as the growth and transcriptional responses of two dominant diatoms, Fragilariopsis and Pseudo-nitzschia. We found that community nutrient uptake and primary productivity were elevated under both warming conditions without iron addition (relative to ambient −0.5 °C). This effect was greater than additive under concurrent iron addition and warming. Pseudo-nitzschia became more abundant under warming without added iron (especially at 6 °C), while Fragilariopsis only became more abundant under warming in the iron-added treatments. We attribute the apparent advantage Pseudo-nitzschia shows under warming to up-regulation of iron-conserving photosynthetic processes, utilization of iron-economic nitrogen assimilation mechanisms, and increased iron uptake and storage. These data identify important molecular and physiological differences between dominant diatom groups and add to the growing body of evidence for Pseudo-nitzschia’s increasingly important role in warming SO ecosystems. This study also suggests that temperature-driven shifts in SO phytoplankton assemblages may increase utilization of the vast pool of excess nutrients in iron-limited SO surface waters and thereby influence global nutrient distribution and carbon cycling.
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影响因子：
4.9
作者：
Frolicher, Thomas L.;Sarmiento, Jorge L.;Winton, Michael
通讯作者：
Winton, Michael
影响因子：
3.7
作者：
Andrew, Sarah M.;Morell, Hugh T.;Ellwood, Michael J.
通讯作者：
Ellwood, Michael J.
DOI：
10.1073/pnas.1309345110
发表时间：
2013-12-17
影响因子：
11.1
作者：
Assmy, Philipp;Smetacek, Victor;Wolf-Gladrow, Dieter
通讯作者：
Wolf-Gladrow, Dieter
影响因子：
3.7
作者：
Coello-Camba, Alexandra;Agusti, Susana
通讯作者：
Agusti, Susana
影响因子：
4.5
作者：
Cohen, Natalie R.;Mann, Elizabeth;Marchetti, Adrian
通讯作者：
Marchetti, Adrian