Environmental carbonate chemistry selects for phenotype of recently isolated strains of Emiliania huxleyi
Environmental carbonate chemistry selects for phenotype of recently isolated strains of Emiliania huxleyi
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DOI：
10.1016/j.dsr2.2016.02.010
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发表时间：
2016-05-01
影响因子：
3
通讯作者：
Brownlee, Colin
中科院分区：
文献类型：
--
作者：
Rickaby, Rosalind E. M.;Hermoso, Michael;Brownlee, Colin
球石藻，特别是Emiliania huxleyi，是多产的生物矿化剂，在许多条件下，占主导地位的海洋真核浮游生物群落。它们的光合作用和形成钙化鳞片（球石）的能力使它们在全球碳循环中处于独特的地位。关于E. huxleyi到海洋酸化。因此，迫切需要进一步确定这种关键生物在二氧化碳上升的世界中的命运。在本文中，我们调查了新分离的，遗传多样性，菌株的表型。来自英国海洋酸化研究计划（UKOA）的huxleyi在不列颠群岛，北极和南大洋巡航。我们发现不同菌株的生理和光合参数存在连续的多样性。huxleyi形态型A在实验室中施加的均匀环境条件下。这种生理学最好的解释是适应碳酸盐化学在前栖息地，而不是由遗传指纹，如颗石藻形态基序（CMM）规定。一阶，每个菌株的光合能力是一个功能的水CO2的可用性，和钙化率，暗示碳浓缩能力和钙化之间的联系。每个菌株的钙化率与分离地点的自然环境[CO 32-]呈线性相关，但当钙化受到低CO2可用性和/或缺乏碳浓缩机制的限制时，少数例外菌株在最高[CO 32-]下显示低钙化率。我们提出了O-2电极测量旁边的球石氧同位素组成和糖醛酸含量（UAC）的球石相关的多糖（CAP），作为间接的工具，以显示不同的碳浓缩能力的菌株。在我们最近分离的菌株收集中揭示的环境选择指向通过更快的光合作用而在未来战胜缓慢生长的形态型B/C和R（其也缺乏碳浓缩机制），以及形态型A的轻度钙化菌株，但其钙化速率高度依赖于表面海洋饱和状态。对E.赫胥黎对现代海洋中碳酸盐化学的反应似乎是从一系列表型中进行选择。(C)2016爱思唯尔有限公司版权所有。
Coccolithophorid algae, particularly Emiliania huxleyi, are prolific biomineralisers that, under many conditions, dominate communities of marine eukaryotic plankton. Their ability to photosynthesise and form calcified scales (coccoliths) has placed them in a unique position in the global carbon cycle. Contrasting reports have been made with regards to the response of E. huxleyi to ocean acidification. Therefore, there is a pressing need to further determine the fate of this key organism in a rising CO2 world. In this paper, we investigate the phenotype of newly isolated, genetically diverse, strains of E. huxleyi from UK Ocean Acidification Research Programme (UKOA) cruises around the British Isles, the Arctic, and the Southern Ocean. We find a continuum of diversity amongst the physiological and photosynthetic parameters of different strains of E. huxleyi morphotype A under uniform, ambient conditions imposed in the laboratory. This physiology is best explained by adaptation to carbonate chemistry in the former habitat rather than being prescribed by genetic fingerprints such as the coccolithophore morphology motif (CMM). To a first order, the photosynthetic capacity of each strain is a function of both aqueous CO2 availability, and calcification rate, suggestive of a link between carbon concentrating ability and calcification. The calcification rate of each strain is related linearly to the natural environmental [CO32-] at the site of isolation, but a few exceptional strains display low calcification rates at the highest [CO32-] when calcification is limited by low CO2 availability and/or a lack of a carbon concentrating mechanism. We present O-2-electrode measurements alongside coccolith oxygen isotopic composition and the uronic acid content (UAC) of the coccolith associated polysaccharide (CAP), that act as indirect tools to show the differing carbon concentrating ability of the strains. The environmental selection revealed amongst our recently isolated strain collection points to the future outcompetition of the slow growing morphotypes B/C and R (which also lack a carbon concentrating mechanism) by more rapidly photosynthesising, and lightly calcified strains of morphotype A but with their rate of calcification highly dependent on the surface ocean saturation state. The mechanism of E. huxleyi response to carbonate chemistry in the modern ocean appears to be selection from a continuum of phenotype. (C) 2016 Elsevier Ltd. All rights reserved.