摘要
通过室内模拟培养,研究了孔石莼存在下过量无机氮对水体无机碳体系变化的影响及其机制.结果表明,无机氮的添加均会导致水体DIC、HCO3-和p(CO2)的减少,pH和CO23-的增加.当NO3--N和NH4+-N浓度分别低于71μmol·L-1和49.7μmol·L-1时,随着营养盐浓度的增加,水体无机碳体系各组分的变化幅度增大,其中以NO3-3和NH4-3组变化最为明显,至实验结束DIC分别较空白组下降了151μmol·L-1和232μmol·L-1;当NO3--N和NH4+-N浓度分别高于355μmol·L-1和248.5μmol·L-1时,则随着浓度的增加无机碳各组分的变化幅度减小.对无机碳的减少与孔石莼的生长(Δm)做相关性分析发现,二者密切相关(r=-0.91,p<0.0001,n=11),当营养盐浓度促进孔石莼的生长时,水体DIC浓度下降,孔石莼干重增加;反之,当营养盐过量时,则会对其产生毒性作用,抑制其对无机碳的吸收.NH4+-N对海水无机碳体系的影响较NO3--N明显.
Effects of macronutrient （NO3^- -N and NH4^＋-N） on inorganic carbon system of water with Ulva pertusa existed were studied in laboratory simulation experiments. The results demonstrated that nutrient enrichment induced DIC, HCO3^- and p （CO2） decreased while pH and CO3^2- increased. The seawater changed from carbon source to carbon sink. During the experiments, the concentration of DIC, HCO3^- and p（CO2） decreased with increasing concentration of nutrient when the NO3^--N and NH4^＋ -N were less than critical concentration. The concentration of DIC changed most at the NO3-3 and NH4-3 groups, which decreased 151 μmol·L^-1 and 232 μmol·L^-1 compared with the control groups in the end of experiment. The increased dry weight of Ulva pertusa （ △m ） of nutrient addition groups showed a significant negative correlation with △DIC （ r = - 0.91, p 〈 0.000 1, n = 11）. The main controlling factor to inorganic carbon variation is the adaptation of Ulva pertusa to different DIN. When the concentration of DIN facilitates the growth of Ulva pertusa, the concentration of DIC decreased and dry weight of Ulva pertusa increased. NH4^＋ -N has more influence on inorganic carbon system than NO3^- -N.
出处
《环境科学》
EI
CAS
CSCD
北大核心
2009年第7期1906-1913,共8页
Environmental Science
基金
国家重点基础研究发展规划(973)项目(2007CB407305)
国家海洋局海洋生态环境科学与工程重点实验室开放基金项目(MESE-2008-07)
关键词
模拟实验
过量无机氮
无机碳体系
孔石莼
simulated experiments
macro-nitrogen
inorganic carbon system
Ulva pertusa
