| 碳酸酐酶胞外酶影响下的岩溶湖泊微藻碳汇研究 |
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| 引用本文： | 李海涛,吴沿友,付兵.碳酸酐酶胞外酶影响下的岩溶湖泊微藻碳汇研究[J].中国岩溶,2022,41(3):395. |
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| 作者姓名： | 李海涛 吴沿友 付兵 |
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| 作者单位： | 1.贵州农业职业学院, 贵州 贵阳 551400 |
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| 基金项目： | 国家自然科学基金(U1612441-2)； 贵州省科学技术基金资助项目(黔科合基础-ZK[2022]-217) |
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| 摘 要： | 以岩溶湖泊——红枫湖的微藻为研究对象，通过添加两种标记稳定碳同位素组成的无机碳进行室内模拟岩溶环境条件；并通过添加不同浓度的乙酰唑胺（AZ），来模拟岩溶湖泊中碳酸酐酶胞外酶活性差异的各类微藻。重点监测微藻蛋白质含量及其稳定碳同位素组成变化等指标，计算其对不同来源无机碳的吸收利用份额，并结合微藻的生物量生长指标，最终计算出碳酸酐酶胞外酶活性差异的各种微藻的碳汇能力。结果显示:在岩溶湖泊的自然水体中，碳酸酐酶胞外酶活性强的微藻碳汇能力是缺乏碳酸酐酶胞外酶的微藻碳汇能力的5倍。碳酸酐酶胞外酶对微藻光合碳汇能力的影响显著。
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| 关 键 词： | 微藻 岩溶碳汇 碳酸酐酶 岩溶湖泊 |
| 收稿时间： | 2022-02-20 |
Carbon sink of microalgae in karst lakes under the influence of the extracellular of carbonic anhydrase |
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| Institution: | 1.Guizhou Vocational College of Agriculture, Guiyang,Guizhou 551400, China2.State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang,Guizhou 550081, China |
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| Abstract: | Carbonic anhydrase is a metal enzyme which contains Zn. It has the characteristics of catalyzing the mutual conversion between CO2 and HCO3? with high efficiency and specificity. It plays an important role in promoting the global carbon cycle, such as carbonate dissolution, photosynthesis of plants and atmospheric CO2 hydration reaction.Karst carbon sink refers to the biological carbon sequestration process which is the aquatic organisms represented by microalgae absorb and utilize inorganic carbon represented by HCO3? from carbonate karst erosion. In karst lake, under the catalytic action of carbonic anhydrase, it can greatly accelerate the dissolution process of carbonate rock, significantly affect the pH and the concentration of HCO3? of karst lake water,and promote the growth of microalgae. Correspondingly, the karst carbon sink capacity of microalgae increased with the increasing of biomass. And on this basis, the life activities of microalgae can promote the dissolution process of the karstification. Finally, it forms an aquatic photosynthetic carbon cycling system between carbonate rocks and atmosphere with the participation of microalgae.Isotopes are different atoms of the same element with the same number of protons but different numbers of neutrons. Isotopes in nature can be divided into radioisotopes and stable isotopes according to their stability. Stable isotope analysis is accurate, pollution-free and non-destructive, which can be used to study the interaction between organisms and the environment. It has been widely used in the field of plant ecology.Stable isotopes were used in this study.Microalgae is the primary producer of aquatic ecosystem, which refers to a class of microscopic plants living in water and living in a planktonic lifestyle. The character of microalgae in karst lakes have typical seasonal fluctuation and spatial heterogeneity. The activity of carbonic anhydrase was different significantly among various microalgae. In spring and summer, green algae dominated with strong carbonic anhydrase activity and fast growth; while in autumn and winter, the dominated algae is the diatoms which with weak carbonic anhydrase activity and slow growth. In conclusion, the activity of carbonic anhydrase determines the ability of microalgae to obtain inorganic carbon, which brings about great differences in the growth of various microalgae,and then affects a huge impact in the capacity of photosynthetic carbon sink in microalgae.Acetazolamide (AZ) belongs to the sulfonamide group which is a specific inhibitor about the extracellular of carbonic anhydrase. Its substrate is CAex, and it has a good inhibitory effect on CAex.In this study, the microalgae in Hongfeng lake, a karst plateau lake,was taken as the research object, we simulated karst condition in laboratory by adding different inorganic carbon labeled. In addition, different concentrations of AZ were added to simulate the difference of carbonic anhydrase extracellular enzyme activity of different microalgae of karst lakes. By monitoring the protein content and stable carbon isotope composition of microalgae, the proportion of absorption and utilization of inorganic carbon from different sources was calculated. The carbon sink of microalgae with different extracellular enzyme activities were calculated based on the biomass growth index of microalgae and the above proportion. The results showed that the carbon sink capacity of microalgae with high activity of carbonic anhydrase was 5 times higher than that of microalgae without carbonic anhydrase in natural water of karst lake. The extracellular carbonic anhydrase had significant effects on the photosynthetic carbon sink capacity of microalgae.Although the content of native bicarbonate is high in karst lake water, inorganic carbon utilized by microalgae mainly comes from atmospheric carbon dioxide (photosynthetic carbon sink), and only a small amount of native bicarbonate (karst carbon sink) is utilized in karst lake water. The main contribution of carbonic anhydrase extracellular enzyme is accelerating the absorption, utilization and conversion efficiency of atmospheric carbon dioxide by microalgae, and finally promoted the growth of microalgae, carbon sequestration and increase sink. It is of great significance for scientific selection of human using microalgae with strong extracellular enzyme activity of carbonic anhydrase to increase carbon sink and serve the national strategy of "carbon neutrality". |
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