Modeling the transformation of atmospheric CO 2 into microalgal biomass
Modeling the transformation of atmospheric CO 2 into microalgal biomass
复制标题
模拟大气 CO 2 转化为微藻生物质的过程
DOI：
10.1039/c7an01054k
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发表时间：
2017
期刊：
影响因子：
--
通讯作者：
Vogt, Frank
中科院分区：
文献类型：
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作者：
Hasan, Mohammed Fahad;Vogt, Frank
海洋浮游植物是大气二氧化碳的重要汇，因为它封存了大量的温室气体用于生物质生产。为了评估微藻对全球变暖的平衡作用，需要确定它们固定的二氧化碳量。对于这项任务，必须了解哪些环境和生理参数控制着从大气二氧化碳到微藻生物质的转变。然而，实验分析具有挑战性，因为已经发现化学环境对微藻细胞（直径典型值5-20μm）的生理特性有重大影响。此外，细胞只能与其邻近区域发生化学相互作用，因此需要在微观空间尺度上研究化合物封存。由于这些原因，计算机模拟是比实验研究更有前景的方法。已经开发出模拟软件，描述大气中的二氧化碳溶解到海洋中，然后形成 HCO3−，然后将其输送到单个微藻细胞。该模型的第二部分描述了不同细胞种类对这种营养物质 HCO3− 的竞争，以及细胞生产中对它的吸收和利用。在不同的大气二氧化碳条件下，分别培养两种微藻，即杜氏盐藻和微绿球藻，并在竞争情况下进行培养。结果表明，该新模型对生物量产量的预测与实验流式细胞术结果非常吻合。经过模型验证，已应用于浮游植物生成的长期预测。这些研究的动机是细胞生产是否会随着培养物的生长而减慢。这是相关的，因为细胞生产率的降低意味着培养物吸收二氧化碳的能力的增加也会减慢。由此产生的一个含义是，人为二氧化碳的增加可能无法通过浮游植物产量的增加来抵消。模型研究发现，对于提供给单一物种培养物以及竞争场景中的物种的几种不同的大气二氧化碳水平，细胞生产率确实会随着时间的推移而减慢。
Marine phytoplankton acts as a considerable sink of atmospheric CO2 as it sequesters large quantities of this greenhouse gas for biomass production. To assess microalgae's counterbalancing of global warming, the quantities of CO2 they fix need to be determined. For this task, it is mandatory to understand which environmental and physiological parameters govern this transformation from atmospheric CO2 to microalgal biomass. However, experimental analyses are challenging as it has been found that the chemical environment has a major impact on the physiological properties of the microalgae cells (diameter typ. 5–20 μm). Moreover, the cells can only chemically interact with their immediate vicinity and thus compound sequestration needs to be studied on a microscopic spatial scale. Due to these reasons, computer simulations are a more promising approach than the experimental studies. Modeling software has been developed that describes the dissolution of atmospheric CO2 into oceans followed by the formation of HCO3− which is then transported to individual microalgae cells. The second portion of this model describes the competition of different cell species for this HCO3−, a nutrient, as well as its uptake and utilization for cell production. Two microalgae species, i.e. Dunaliella salina and Nannochloropsis oculata, were cultured individually and in a competition situation under different atmospheric CO2 conditions. It is shown that this novel model's predictions of biomass production are in very good agreement with the experimental flow cytometry results. After model validation, it has been applied to long-term prediction of phytoplankton generation. These investigations were motivated by the question whether or not cell production slows down as cultures grow. This is of relevance as a reduced cell production rate means that the increase in a culture's CO2-sinking capacity slows down as well. One implication resulting from this is that an increase in anthropogenic CO2 may not be counterbalanced by an increase in phytoplankton production. Modeling studies have found that for several different atmospheric CO2 levels provided to single-species cultures as well as to species in competing scenarios the cell production rate does slow down over time.