| Budget Amount *help |
¥17,160,000 (Direct Cost: ¥13,200,000、Indirect Cost: ¥3,960,000)
Fiscal Year 2020: ¥2,730,000 (Direct Cost: ¥2,100,000、Indirect Cost: ¥630,000)
Fiscal Year 2019: ¥3,770,000 (Direct Cost: ¥2,900,000、Indirect Cost: ¥870,000)
Fiscal Year 2018: ¥3,640,000 (Direct Cost: ¥2,800,000、Indirect Cost: ¥840,000)
Fiscal Year 2017: ¥7,020,000 (Direct Cost: ¥5,400,000、Indirect Cost: ¥1,620,000)
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| Outline of Final Research Achievements |
A huge amount of volcanic tephra has been intermittently added to forest ecosystems in subduction zones such as in Japan through its geological time. Tephra contains primary-mineral phosphorus, which is one of the most important biophilic nutrients, and tephra fall might have supplied a significant amount of phosphorus to the ecosystems. However, this hypothesis has not been tested. We collected soils from a total of 20 natural forests throughout Japan and determined the concentration of amorphous minerals as an index of tephra fall. The concentration of amorphous minerals varied greatly, mostly depending on the distance to a nearby volcano, and significantly correlated with the concentration of soil total and available phosphorus. This finding suggests that tephra fall provides a substantial amount of phosphorus to forest ecosystems and biogeochemically maintains the forest ecosystems in Japan.
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