Zhang Nai-xing, Song Jin-ming, He Zhi-peng, Zheng Guo-xia, Zhang Peng, Xu Ya-yan
Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China.
Huan Jing Ke Xue. 2008 Jun;29(6):1469-77.
The influence of excessive inorganic nitrogen (NO3-, NH4+, NO2-) on the pH, inorganic carbon system and air-sea CO2 flux was studied in laboratory seawater simulation experiments. The result indicates that the excessive inorganic nitrogen significantly has an important influence on the inorganic carbon system in all conditions. At the NO3- addition groups, HCO3- and p (CO2) increase while pH and CO3(2-) decrease when the concentration of NO3- < or = 37.60 micromol x L(-1). But high concentrations > or = 188 micromol x L(-1) is just the reverse. The seawater changes from carbon source to carbon sink of atmospheric CO2 with NO3- addition increased. At the NH4+ addition groups, HCO3- and p (CO2) decrease while pH and CO3(2-) increase when the concentration of NH4+ < or = 25.20 micromol x L(-1). However, when the concentration of NH4+ > or = 126 micromol x L(-1), the concentrations of HCO3- and p (CO2) increase with NH4+ addition and the seawater changes from carbon sink to carbon source of atmospheric CO2 and the intensity of carbon source has a positive relationship with the concentration of NH4+. At the NO2- addition groups, the concentrations of HCO3- and p (CO2) decrease while pH and CO3(2-) increase with time scale and the seawater acts as a strong carbon sink with NO2- addition of 7.90 micromol x L(-1). While at the other NO2- concentration levels, the carbon sink is weak in seawater. The Chl-a concentration of nutrient addition groups compared with control (delta Chl-a) shows a significant negative correlation with delta p (CO2) (r = -0.87, p < 0.000 1, n = 16). The main controlling factor to the variation of inorganic carbon system is the adaptation of phytoplankton to different form and concentration of nitrogen.
通过实验室海水模拟实验，研究了过量无机氮（NO3-、NH4+、NO2-）对pH值、无机碳系统和海气CO2通量的影响。结果表明，在所有条件下，过量无机氮对无机碳系统均有显著影响。在添加NO3-的实验组中，当NO3-浓度≤37.60 μmol·L-1时，HCO3-和p(CO2)升高，而pH值和CO3(2-)降低。但当浓度≥188 μmol·L-1时则相反。随着NO3-添加量增加，海水从大气CO2的碳源转变为碳汇。在添加NH4+的实验组中，当NH4+浓度≤25.20 μmol·L-1时，HCO3-和p(CO2)降低，而pH值和CO3(2-)升高。然而，当NH4+浓度≥126 μmol·L-1时，HCO3-和p(CO2)浓度随NH4+添加量增加而升高，海水从大气CO2的碳汇转变为碳源，且碳源强度与NH4+浓度呈正相关。在添加NO2-的实验组中，HCO3-和p(CO2)浓度随时间尺度降低，而pH值和CO3(2-)升高，添加7.90 μmol·L-1 NO2-时海水表现为强碳汇。而在其他NO2-浓度水平下，海水碳汇较弱。营养盐添加组与对照组相比的Chl-a浓度变化（δChl-a）与δp(CO2)呈显著负相关（r = -0.87，p < 0.000 1，n = 16）。无机碳系统变化的主要控制因素是浮游植物对不同形态和浓度氮的适应性。
