Strong effects of elevated CO2 on freshwater microalgae and ecosystem chemistry
Strong effects of elevated CO2 on freshwater microalgae and ecosystem chemistry
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DOI：
10.1002/lno.11298
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发表时间：
2020-02-01
影响因子：
4.5
通讯作者：
Scott, Kathleen M.
中科院分区：
文献类型：
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作者：
Brown, Terry-Rene;Lajeunesse, Marc J.;Scott, Kathleen M.
淡水系统的碳酸盐化学范围可以从无机碳限制到相对于大气的过饱和，并且这些系统的 pH 值可以在时间和空间上从碱性到酸性变化。确定这些异质系统如何响应大气二氧化碳的增加对于了解这些变化的全球影响至关重要。在这里，我们综合了来自不同系统的 22 项研究，以探索二氧化碳浓度升高对淡水化学和微藻的影响，而微藻构成了自养食物网的基础。在淡水系统的可变性中，二氧化碳浓度升高会降低 pH 值并增加溶解的无机碳，从而显着影响水化学。微藻也受到二氧化碳浓度升高的影响，测量结果显示：(1) 通过微藻碳与养分比率获取养分、(2) 光合作用活性和 (3) 生长有所增加。虽然这些影响是通过对照实验测量的，但结果表明大气二氧化碳浓度升高对淡水生态系统有广泛的潜在影响。我们的综合还发现了一些知识差距。一般来说，需要更大的样本量和更长持续时间的研究才能获得更稳健的分析和结论。此外，需要对一系列淡水生态系统类型进行更多的现场实验以及涉及底栖物种和多个营养级的研究，以加强对淡水系统内部和之间发现的广泛变异性的全球预测。
The carbonate chemistry of freshwater systems can range from inorganic carbon-limited to supersaturated with respect to the atmosphere, and the pH of these systems can vary temporally and spatially from alkaline to acidic. Determining how these heterogeneous systems respond to increases in atmospheric CO2 is critical to understanding global impacts of these changes. Here, we synthesize 22 studies from a variety of systems to explore the effects of elevated CO2 on freshwater chemistry and microalgae, which form the base of autotrophic food webs. Across the variability in freshwater systems, elevated CO2 significantly affected water chemistry by decreasing pH and increasing dissolved inorganic carbon. Microalgae were also affected by elevated CO2 with measured increases in (1) nutrient acquisition through microalgal carbon-to-nutrient ratios, (2) photosynthetic activity, and (3) growth. While these effects were measured from controlled experiments, the results indicate a wide range of potential freshwater ecosystem effects from elevated atmospheric CO2. Our synthesis also identified several knowledge gaps. Generally, larger sample sizes and studies of longer duration are needed for more robust analyses and conclusions. Additionally, more field experiments across a range of freshwater ecosystem types and studies involving benthic species and multiple trophic levels are needed to strengthen global predictions across the broad variability found within and among freshwater systems.