Two Southern Ocean diatoms are more sensitive to ocean acidification and changes in irradiance than the prymnesiophyte Phaeocystis antarctica.
Two Southern Ocean diatoms are more sensitive to ocean acidification and changes in irradiance than the prymnesiophyte Phaeocystis antarctica.
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DOI：
10.1111/ppl.12539
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发表时间：
2017-06
影响因子：
6.4
通讯作者：
S. Trimborn;S. Thoms;Tina Brenneis;Jasmin P Heiden;Sára Beszteri;K. Bischof
中科院分区：
文献类型：
--
作者：
S. Trimborn;S. Thoms;Tina Brenneis;Jasmin P Heiden;Sára Beszteri;K. Bischof
为了更好地了解海洋酸化（OA）和光照变化对南大洋浮游植物生理的影响，我们研究了pCO 2（380和800 µatm）结合低辐照度和高辐照度（20或50和200 µmol光子m-2 s-1）对生长的影响，研究了三种生态相关物种脆弱角毛藻（Chaetoceros debilis）、克氏脆杆藻（Fragilariopsis kerguelensis）和南极棕囊藻（Phaeocystis anaerotica）对颗粒有机碳（POC）的固定作用和光合生理。无论光照情况如何，OA都不能刺激任何测试物种的生长和每个细胞的POC，两种硅藻甚至在生长中显示出负响应（例如C. debilis）或POC含量（例如F. kerguelensis）在OA结合强光下进行。对于这两种硅藻，光系统II（Fv /Fm）的最大量子产率也在这些条件下降低，表明光化学效率降低。为了抵消OA和强光的负面影响，两种硅藻表现出不同的光适应策略。叶绿素a（Chl a）和岩藻黄质（fucoxanthin）含量在C. debilis潜在地最大化光吸收，F. kerguelensis表现出降低Chl a每细胞，增加断开的触角从光系统II反应中心和强烈降低绝对电子传递速率（ETR）。F. kerguelensis可能被解释为不同的物种特异性的策略，调整可用流量的腺苷三磷酸和烟酰胺腺嘌呤二核苷酸磷酸。总体而言，我们的研究结果表明，南极原甲藻比两种硅藻更耐受OA和辐照度的变化，这可能对生态地球化学循环具有重要意义。
To better understand the impact of ocean acidification (OA) and changes in light availability on Southern Ocean phytoplankton physiology, we investigated the effects of pCO2 (380 and 800 µatm) in combination with low and high irradiance (20 or 50 and 200 µmol photons m-2 s-1 ) on growth, particulate organic carbon (POC) fixation and photophysiology in the three ecologically relevant species Chaetoceros debilis, Fragilariopsis kerguelensis and Phaeocystis antarctica. Irrespective of the light scenario, neither growth nor POC per cell was stimulated by OA in any of the tested species and the two diatoms even displayed negative responses in growth (e.g. C. debilis) or POC content (e.g. F. kerguelensis) under OA in conjunction with high light. For both diatoms, also maximum quantum yields of photosystem II (Fv /Fm ) were decreased under these conditions, indicating lowered photochemical efficiencies. To counteract the negative effects by OA and high light, the two diatoms showed diverging photoacclimation strategies. While cellular chlorophyll a (Chl a) and fucoxanthin contents were enhanced in C. debilis to potentially maximize light absorption, F. kerguelensis exhibited reduced Chl a per cell, increased disconnection of antennae from photosystem II reaction centers and strongly lowered absolute electron transport rates (ETR). The decline in ETRs in F. kerguelensis might be explained in terms of different species-specific strategies for tuning the available flux of adenosine triphosphate and nicotinamide adenine dinucleotide phosphate. Overall, our results revealed that P. antarctica was more tolerant to OA and changes in irradiance than the two diatoms, which may have important implications for biogeochemical cycling.