Soil and stream water acidification in a forested catchment in central Japan
Soil and stream water acidification in a forested catchment in central Japan
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DOI：
10.1007/s10533-009-9362-4
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发表时间：
2010-03
期刊：
影响因子：
4
通讯作者：
O. Nakahara;Masamichi Takahashi;H. Sase;Toshiro Yamada;K. Matsuda;T. Ohizumi;H. Fukuhara;Takanobu Inoue;A. Takahashi;Hiroyasu Kobayashi;R. Hatano;T. Hakamata
中科院分区：
文献类型：
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作者：
O. Nakahara;Masamichi Takahashi;H. Sase;Toshiro Yamada;K. Matsuda;T. Ohizumi;H. Fukuhara;Takanobu Inoue;A. Takahashi;Hiroyasu Kobayashi;R. Hatano;T. Hakamata
东亚的快速工业化由于大气沉降对陆地和淡水生态系统造成了不利影响。在整个20世纪90年代，在日本中部的伊吉拉湖森林流域观察到河流pH值和碱度下降以及NO3−浓度增加。我们利用大气沉降、土壤化学、河水化学和森林生长的数据调查了这些变化。氢、硫和氮的平均大气沉降量（湿+干）分别为0.83、0.57和1.37 kmol ha− 1年− 1，是日本最高的水平之一。1994年以前大气沉积物一般减少，1994年以后增加。该集水区对酸敏感;溪流碱度较低（134 μmolcl−1），表层矿质土壤的pH值从1990年的4.5下降到2003年的3.9。从20世纪80年代末到21世纪初，NO3−的浓度几乎翻了一番（从22 μmolcl− 1到42 μmolcl−1）。在1996/1997年之前，河流NO3-浓度主要受水温控制，此后则受河流排放量控制。在1996/1997年之前的生长季节，溪流NO3-浓度下降，但此后这种季节性消失。集水区变得氮饱和1996/1997年（从第1阶段变为第2阶段），可能是由于1994年夏季干旱导致森林生长率下降，日本赤松因松树枯萎病落叶，日本雪松林成熟，以及由于土壤碱化而引起的氮矿化和硝化作用的刺激（增加交换性Ca ~（2+）和土壤pH）。河流pH值和碱度在1996/1997年开始下降。自1996/1997年以来，生长季节NO3−排放量的增加似乎是河流酸化的主要原因。自1994年以来，大气沉降的增加可能促成了这一变化。
Rapid industrialization in East Asia is causing adverse effects due to atmospheric deposition in terrestrial and freshwater ecosystems. Decreasing stream pH and alkalinity and increasing NO3−concentrations were observed throughout the 1990s in the forested Lake Ijira catchment in central Japan. We investigated these changes using data on atmospheric deposition, soil chemistry, stream water chemistry, and forest growth. Average atmospheric depositions (wet + dry) of 0.83, 0.57, and 1.37 kmol ha−1year−1for hydrogen, sulfur, and nitrogen, respectively, were among the highest levels in Japan. Atmospheric deposition generally decreased before 1994 and increased thereafter. The catchment was acid-sensitive; stream alkalinity was low (134 μmolcl−1) and pH in surface mineral soils decreased from 4.5 in 1990 to 3.9 in 2003. Stream NO3−concentration nearly doubled (from 22 to 42 μmolcl−1) from the late 1980s to the early 2000s. Stream NO3−concentration was controlled primarily by water temperature before 1996/1997 and by stream discharge thereafter. Stream NO3−concentrations decreased during the growing season before 1996/1997, but this seasonality was lost thereafter. The catchment became nitrogen-saturated (changing from stage 1 to 2) in 1996/1997, possibly because of declining forest growth rates due to the 1994 summer drought, defoliation of Japanese red pine by pine wilt disease, maturation of Japanese cedar stands, and stimulation of nitrogen mineralization and nitrification due to alkalinization of soils (increased exchangeable Ca2+and soil pH) after the summer drought. Stream pH and alkalinity began decreasing in 1996/1997. The enhanced growing-season NO3−discharge since 1996/1997 appeared to be the major cause of stream acidification. Increased atmospheric deposition since 1994 may have contributed to this change.