摘要
硝酸盐异化还原包括反硝化、厌氧氨氧化和异化硝酸盐还原为铵(dissimilatory nitrate reduction to ammonium, DNRA)等氮循环中的关键过程,它们影响着海洋中氮元素的移除和保留。在全球变暖的背景下,沉积物硝酸盐异化还原过程将会受到不同程度的影响。但是,尚不清楚珊瑚礁区钙质砂和硅质砂沉积物硝酸盐异化还原过程对温度升高的响应差异。因此,本研究利用15N同位素示踪技术和沉积物的升温受控培养,探究温度升高条件下涠洲岛珊瑚礁区不同类型沉积物中硝酸盐异化还原的响应。结果表明, DNRA和反硝化过程在两种不同类型的沉积物中对升温的响应表现出显著的差异性,在硅质砂中反硝化速率和DNRA速率随温度显著上升,而钙质砂则相反,这可能与不同沉积物中微生物群落结构差异有关。由于厌氧氨氧化对升温更为敏感,反硝化在氮移除方面变得愈发重要,但其副产物N2O可能会对气候造成一定的负面影响。温度升高导致DNRA对硝酸盐异化贡献度增加,环境氮移除能力降低,这会加剧涠洲岛海域氮过剩的情况,对珊瑚礁生态系统产生不利影响。
Dissimilatory nitrate reduction processes,including denitrification,anaerobic ammonium oxidation,and dissimilatory nitrate reduction to ammonium(DNRA)regulate the removal and retention of nitrogen elements in the ocean.Global warming affecting the nitrogen cycling processes in sediments,but it is not yet clear the differences in response of dissimilatory nitrate reduction processes in carbonate sand and silicate sand sediments to increased temperature.Therefore,we used 15N isotope tracing technology and temperature-controlled incubation of sediments to investigate the response of dissimilatory nitrate reduction processes in different sediment types in the coral reef area of the Weizhou Island to increased temperature.The results indicate that DNRA and denitrification processes exhibited significant differences in response to increased temperature in two different types of sediments.The rates of denitrification and DNRA in silicate sand were significantly increased with the increased temperature,but those in carbonate sand exhibited opposite trend,which may be related to differences in microbial community in different sediments.Due to anaerobic ammonium oxidation process being more sensitive to increased temperature,the contribution of denitrification to nitrogen removal increased,but its byproduct N2O may have a negative impact on climate.In addition,the increase in temperature led to an increase in the contribution of DNRA to nitrate dissimilation reduction,which will exacerbate the negative impact of nitrogen excess on the coral reef ecosystem of the Weizhou Island.
作者
莫丹杨
宁志铭
杨斌
夏荣林
刘志金
MO Danyang;NING Zhiming;YANG Bin;XIA Ronglin;LIU Zhijin(School of Marine Sciences,Guangxi University,Nanning 530004,China;Coral Reef Research Center of China,Guangxi University,Nanning 530004,China;Guangxi Laboratory on the Study of Coral Reefs in the South China Sea,Nanning 530004,China;Jiangsu Key Laboratory of Marine Bioresources and Environment,Jiangsu Ocean University,Lianyungang 222005,China)
出处
《热带海洋学报》
CAS
CSCD
北大核心
2024年第4期137-143,共7页
Journal of Tropical Oceanography
基金
广西自然科学基金项目(2019GXNSFAA185001)
大学生创新创业训练计划项目(S202210593227)。
关键词
反硝化
厌氧氨氧化
DNRA
沉积物
珊瑚礁
denitrification
increased temperature
DNRA
sediments
coral reef
