The impacts of iron limitation and ocean acidification on the cellular stoichiometry, photophysiology, and transcriptome of Phaeocystis antarctica
The impacts of iron limitation and ocean acidification on the cellular stoichiometry, photophysiology, and transcriptome of Phaeocystis antarctica
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DOI：
10.1002/lno.11045
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发表时间：
2019-01-01
影响因子：
4.5
通讯作者：
Trimborn, Scarlett
中科院分区：
文献类型：
--
作者：
Koch, Florian;Beszteri, Sara;Trimborn, Scarlett
南极棕囊藻是世界上最大的高营养低叶绿素区域南大洋 (SO) 浮游植物群落的重要组成部分，并且面临长期铁 (Fe) 限制。由于 SO 吸收了 40% 的人为 CO2，因此南极洲 P. antarctica 还必须应对海洋酸化 (OA)。然而，目前还缺乏研究 Fe 限制和 OA 对微量金属 (TM) 化学计量、转录组和光生理反应以及 Fe 化学反应的影响的机制研究。这项研究表明，南极洲南极洲对铁的限制有强烈的反应，会降低其生长速度和颗粒有机碳（POC）的产量。所有 TM 的细胞浓度（而不仅仅是 Fe）都大大降低，这表明 Fe 的限制可能会导致细胞受到另一个 TM 的二次限制。 P. antarctica 能够根据 Fe 的限制来调整其光生理学，从而导致 PSII 上的绝对电子传输速率相似。尽管 OA 在限制 Fe 和补充 Fe 的处理中刺激生长，但细胞 POC 的轻微减少对 POC 产生没有产生净影响。此外，由于 OA 导致差异表达的基因相对较少。最后，这项研究表明，在我们的培养条件下，OA不会影响海水中的无机铁或腐殖酸类物质，但会引发南极磷虾产生类腐殖酸物质。该物种在所有 Fe 条件下都能很好地适应 OA，使其在未来海洋中比更敏感的物种具有竞争优势。
Phaeocystis antarctica is an integral player of the phytoplankton community of the Southern Ocean (SO), the world's largest high-nutrient low-chlorophyll region, and faces chronic iron (Fe) limitation. As the SO is responsible for 40% of anthropogenic CO2 uptake, P. antarctica must also deal with ocean acidification (OA). However, mechanistic studies investigating the effects of Fe limitation and OA on trace metal (TM) stoichiometry, transcriptomic, and photophysiological responses of this species, as well as on the Fe chemistry, are lacking. This study reveals that P. antarctica responded strongly to Fe limitation by reducing its growth rate and particulate organic carbon (POC) production. Cellular concentrations of all TMs, not just Fe, were greatly reduced, suggesting that Fe limitation may drive cells into secondary limitation by another TM. P. antarctica was able to adjust its photophysiology in response to Fe limitation, resulting in similar absolute electron transport rates across PSII. Even though OA-stimulated growth in Fe-limited and -replete treatments, the slight reduction in cellular POC resulted in no net effect on POC production. In addition, relatively few genes were differentially expressed due to OA. Finally, this study demonstrates that, under our culture conditions, OA did not affect inorganic Fe or humic-acid-like substances in seawater but triggered the production of humic-acid-like substances by P. antarctica. This species is well adapted to OA under all Fe conditions, giving it a competitive advantage over more sensitive species in a future ocean.