2006 Fiscal Year Final Research Report Summary
Evaluation of the influence of acid deposition on ecosystems in Cryptomeria japonica forests in snowy mountainous areas adjacent to the Sea of Japan
| Project/Area Number |
16510020
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Environmental impact assessment/Environmental policy
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| Research Institution | Niigata University |
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Principal Investigator |
NAKATA Makoto Niigata University, Institute of Science and Technology, Associate Prof., 自然科学系, 助教授 (80217744)
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| Project Period (FY) |
2004 – 2006
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| Keywords | Cryptomeria japonica forest / throughfall / slope position / sea salt / epicuticular wax / leaf surface wettability / stream water / acid shock |
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| Research Abstract |
1. The deposition amounts (DAs) of inorganic constituents in a Cryptomeria japonica forest were investigated by measuring throughfall (TF) and stemflow (SF) chemistry at different slope positions in Niigata Prefecture. The total DAs at the upper, mid-, and lower slopes were 2.35, 2.40, and 1.70 times higher than that from rainfall, respectively. Deposition of most inorganic constituents, particularly those originating from sea salts, was higher significantly at the upper slope than the lower slope, which may have been due to materials transported by wind. Mean wind velocity at the nearest weather station showed a more significant positive correlation with the DAs (except for K^+ and nitrogen compounds), particularly for those originating from sea salts, than precipitation amount in the study area, especially at higher slope positions.
2. The DAs of NH_4^+ and K^+ from TF+SF might have a large effect on canopy interactions. The contact angle (CA) of water droplets on the C japonica leaves decreased with leaf aging, suggesting that surface wettability increases with leaf age. The K^+ concentration in TF was negatively correlated with the CA of one-year-old leaves, while the NH_4^+ concentration was positively correlated with the CA. The net DAs of NH_4^+ and NO_3^-from TF were positively correlated with the CA. The increase in leaf surface wettability may accelerate leaching of K^+ or uptake of nitrogen compounds on the forest canopy.
3. Stream water chemistry was compared between neighboring C japonica evergreen coniferous (CFs) and deciduous broad-leaved forests (BFs). The stream water chemistry was characterized by extremely high concentrations of Cl-and Na^+, which were thought to be mostly derived from sea salts. Acid shock was evident from late February to mid-March when the weather improved following cold snowy days in this snowy temperate region. This tendency was clearer in BFs than in CFs due to the different snowmelt patterns between the two forest types.
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