| Project/Area Number |
15310005
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Environmental dynamic analysis
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| Research Institution | University of Tsukuba |
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Principal Investigator |
HIGASHI Teruo University of Tsukuba, Graduate School of Life and Environmental Science, Professor, 大学院・生命環境科学研究科, 教授 (20094170)
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| Co-Investigator(Kenkyū-buntansha) |
TAMURA Kenji University of Tsukuba, Graduate School of Life and Environmental Science, Asssociate Professor, 大学院・生命環境科学研究科, 助教授 (70211373)
KAMIJYO Takashi University of Tsukuba, Graduate School of Life and Environmental Science, Lecturer, Assistant Professor, 大学院・生命環境科学研究科, 講師 (10301079)
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| Project Period (FY) |
2003 – 2005
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| Project Status |
Completed (Fiscal Year 2005)
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| Budget Amount *help |
¥10,500,000 (Direct Cost: ¥10,500,000)
Fiscal Year 2005: ¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 2004: ¥4,100,000 (Direct Cost: ¥4,100,000)
Fiscal Year 2003: ¥4,200,000 (Direct Cost: ¥4,200,000)
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| Keywords | global warming / dissolved organic matter in soils (DOM) / Humus laver (O horizon) / forest ecosystem / soil temperature and moisture / chemical composition of DOM / DOC concentration of leaching solution from soils / 土壌圏溶存有機物 / 土壌呼吸量 / 土壌バイオマス量 |
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| Research Abstract |
In order to investigate the changes and future prediction in the dynamics of dissolved organic matter (DOM) in the O horizon of soils under forest ecosystem due to global warming and temperature increase, DOM after an incubation experiments of O horizon samples under different temperatures for 80days extracted with water and also the DOM in the leaching solution from O horizon under the "Warming Chamber" made of plastics of acryl resins were subjected to the various analyses, especially their chemical composition.
Two representative study sites were selected, one was the Kawakami Experimental Station of Forestry, University of Tsukuba where a typical cool temperate forest ecosystems composed of mainly broad-leaved trees (Qerccus Mongolia spp.) growing on an acid brown forest soils (Dystric Cambisols), and the other was the Oodarumi National Forest where a typical sub-frigid forest ecosystems composed of mainly needle-leaved trees (Abies spp.) growing on a podzolic soils (Typic Podzols).
… More
The simulated experiment for the "Warming Chamber" was conducted during the period from 2003 to 2005 except for winter times. The results obtained were as follows.
1)Concentration of dissolved organic carbon (DOC) in the extracts of O horizon sample increased after the incubation for 80days, especially for the samples under 15℃. The proportion of hydrophilic components of DOM also increased after the incubation as well as extracted cations including calcium, magnesium, potassium, sodium, aluminum and iron. The changes in the chemical structure were inferred from the absorbance at 285nm per DOC,IR spectra and elemental compositions, suggesting the increase in the aromatic carbon with lower "saturation degree".
2)DOC concentration in the leaching solutions increased for the sites under simulated "Warming Chamber" where about 0.5℃ increase in the mean day temperature was observed in the O horizon, suggesting that the higher decomposition rate would be plausible as detected by the measurement of soil respiration rate for the elevated temperature conditions resulting in the release of more aromatic components of DOM. However the increase in the proportion of hydrophilic components of DOM was not clearly detected in the field conditions. Moreover changes of soil properties were observed especially for those in the surface horizons.
3)The increase in temperature, possibly global warming, increase the amount of DOM of aromatic carbon with lower "saturation degree" like phenol and fulvic acids-like substances, and lead to the changes in the properties of soils of surface horizons.
From the comparative study on the two study sites mentioned above it is suggested that the effect of global warming on the amounts and the composition of DOM would be more apparent in the areas under the forest ecosystems of cooler climate. Thus the fundamental knowledge on the dynamics of DOM from forest ecosystems under prevailing global warming was obtained through this project. Less
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