Responses of macroalgae to CO2 enrichment cannot be inferred solely from their inorganic carbon uptake strategy
Responses of macroalgae to CO2 enrichment cannot be inferred solely from their inorganic carbon uptake strategy
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DOI：
10.1002/ece3.4679
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发表时间：
2018-12
影响因子：
2.6
通讯作者：
Luna M. van der Loos;M. Schmid;P. Leal;C. McGraw;Damon Britton;A. Revill;P. Virtue;P. Nichols;C. Hurd
中科院分区：
文献类型：
--
作者：
Luna M. van der Loos;M. Schmid;P. Leal;C. McGraw;Damon Britton;A. Revill;P. Virtue;P. Nichols;C. Hurd
摘要由于大气中CO2浓度的升高，陆地系统中的植物生物量有所增加，但海洋大型藻类对CO2浓度升高的响应尚不清楚。预计到2100年二氧化碳增加200%将提高仅作为二氧化碳获取无机碳的肉质大型藻类的生产力(非二氧化碳浓缩机制[CCM]物种-即没有二氧化碳浓缩机制的物种)，而那些额外吸收碳酸氢盐的物种(CCM物种)预计将做出中性或积极的反应，这取决于它们对碳酸氢盐的亲和力。然而，以前的研究表明，大型肉质藻类对二氧化碳浓度升高表现出各种各样的反应，其潜在的机制在很大程度上是未知的。这项生理研究比较了CCM种(Lomentaria Australis)和非CCM种(Craspedocarpus Ramentaceus)在生长、净光合作用和生化方面对CO2浓度升高的响应。与预期相反，非CCM物种没有增加效应，而CCM物种的增长率高出一倍，这可能是由于高耗能的CCM被下调(S)。节省下来的能量被投入到新的生长中，而不是储存脂肪和脂肪酸。此外，我们进行了全面的文献综述，以考察肉质大型藻类对高二氧化碳的生长和光合作用响应与其碳获取策略的关系。研究结果强调，大型藻类对二氧化碳增加的反应不能仅仅从它们的碳吸收策略中推断出来，需要对更广泛的物种进行有针对性的生理实验，以更好地预测大型藻类对未来海洋变化的反应。
Abstract Increased plant biomass is observed in terrestrial systems due to rising levels of atmospheric CO2, but responses of marine macroalgae to CO2 enrichment are unclear. The 200% increase in CO2 by 2100 is predicted to enhance the productivity of fleshy macroalgae that acquire inorganic carbon solely as CO2 (non‐carbon dioxide‐concentrating mechanism [CCM] species—i.e., species without a carbon dioxide‐concentrating mechanism), whereas those that additionally uptake bicarbonate (CCM species) are predicted to respond neutrally or positively depending on their affinity for bicarbonate. Previous studies, however, show that fleshy macroalgae exhibit a broad variety of responses to CO2 enrichment and the underlying mechanisms are largely unknown. This physiological study compared the responses of a CCM species (Lomentaria australis) with a non‐CCM species (Craspedocarpus ramentaceus) to CO2 enrichment with regards to growth, net photosynthesis, and biochemistry. Contrary to expectations, there was no enrichment effect for the non‐CCM species, whereas the CCM species had a twofold greater growth rate, likely driven by a downregulation of the energetically costly CCM(s). This saved energy was invested into new growth rather than storage lipids and fatty acids. In addition, we conducted a comprehensive literature synthesis to examine the extent to which the growth and photosynthetic responses of fleshy macroalgae to elevated CO2 are related to their carbon acquisition strategies. Findings highlight that the responses of macroalgae to CO2 enrichment cannot be inferred solely from their carbon uptake strategy, and targeted physiological experiments on a wider range of species are needed to better predict responses of macroalgae to future oceanic change.