Shi Man, Zhang Wei Guo, Li Jiang Ye, Yan Shao Hua, Gao Yan
Institute of Agricultural Resources and Environment, Jiangsu Academy of Agricultural Science, Nanjing 210014, China.
College of Forestry, Nanjing Forestry University, Nanjing 210037, China.
Ying Yong Sheng Tai Xue Bao. 2018 Dec;29(12):4239-4247. doi: 10.13287/j.1001-9332.201812.037.
Elevated atmospheric CO has imperceptible impacts on carbon cycle in aquatic ecosystems. However, it remains a question how this process will impact nitrogen cycle that is naturally coupled with carbon cycle. The nitrification and denitrification are two critical processes in the nitrogen cycle. It is reasonable to expect that elevated atmospheric CO will influence both processes. We reviewed the previous literatures concerning the effects of elevated atmospheric CO on the physico-chemical properties, nitrification, denitrification and nitrogen transformation in water bodies. The published results revealed that the elevated CO would reduce the water pH, increase CO and HCO concentrations, but with different effects on the nitrification and denitrification between eutrophic and oligotrophic water. Elevated atmospheric CO could inhibit nitrification and denitrification in oligotrophic water, thereby reduce NO flux from water. The nitrification process in the eutrophic water bodies was also inhibited, but its denitrification might be promoted by the elevated CO. In the eutrophic water bodies, there could be an increase of NO flux when pH was maintained in the range of 7-9. These might eventually result in the accumulation of NH and reduction of NO in water, producing an impact on the microbial diversity. Based on these reviews, we proposed some research gaps related to the relevant research fields as well as some scientific questions that is worth to be further explored. This review would be helpful to better understanding on how the greenhouse effect caused by the elevated atmospheric CO would affect nitrogen cycle in aquatic ecosystem.
大气中二氧化碳浓度升高对水生生态系统的碳循环有难以察觉的影响。然而，这一过程将如何影响与碳循环自然耦合的氮循环仍是一个问题。硝化作用和反硝化作用是氮循环中的两个关键过程。可以合理预期大气中二氧化碳浓度升高会影响这两个过程。我们回顾了先前有关大气中二氧化碳浓度升高对水体物理化学性质、硝化作用、反硝化作用和氮转化影响的文献。已发表的结果表明，二氧化碳浓度升高会降低水体pH值，增加碳酸根离子（CO₃²⁻）和碳酸氢根离子（HCO₃⁻）浓度，但对富营养化水体和贫营养化水体中的硝化作用和反硝化作用有不同影响。大气中二氧化碳浓度升高会抑制贫营养化水体中的硝化作用和反硝化作用，从而减少水体中硝态氮（NO₃⁻）通量。富营养化水体中的硝化作用过程也会受到抑制，但其反硝化作用可能会因二氧化碳浓度升高而得到促进。在富营养化水体中，当pH值保持在7 - 9范围内时，硝态氮通量可能会增加。这些最终可能导致水体中铵态氮（NH₄⁺）积累和硝态氮减少，对微生物多样性产生影响。基于这些综述，我们提出了一些与相关研究领域有关的研究空白以及一些值得进一步探索的科学问题。这篇综述将有助于更好地理解大气中二氧化碳浓度升高引起的温室效应如何影响水生生态系统中的氮循环。
