Impact of permafrost degradation on the discharge of dissolved iron in the Amur River basin

2017 Fiscal Year Final Research Report

• Project/Area Number: 15H05208
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 海外学術
• Research Field: Meteorology/Physical oceanography/Hydrology
• Research Institution: Hokkaido University
• Principal Investigator: SHIRAIWA TAKAYUKI 北海道大学, 低温科学研究所, 准教授 (90235739)
• Co-Investigator(Kenkyū-buntansha): 長尾 誠也 金沢大学, 環日本海域環境研究センター, 教授 (20343014) ; 楊 宗興 東京農工大学, その他の研究科, 教授 (50260526) ; 大西 健夫 岐阜大学, 応用生物科学部, 准教授 (70391638)
• Research Collaborator: TASHIRO Yuto ; KUBO Takumi
• Project Period (FY): 2015-04-01 – 2018-03-31
• Keywords: 溶存鉄 / 永久凍土 / 湿地 / アムール川 / マリ / 気候変動 / ロシア極東 / 河畔域

Outline of Final Research Achievements

We investigated the Tyrma river basin of the Amur river from 2015 to 2017 in order to clarify possible cause of the rapid increase in dissolved iron of the Amur river in the late 1990s. Our 6-times field survey led to the findings of unique landscape called "mari" where sparse larch forest underlain by sphagnum vegetation. The "mari" is found to support sporadic permafrost and supplies significant amount of dissolved iron to its river. The "mari" is found to be developed in riparian zone of the river system by the analyses of indices like NDVI, NDWI and NDSI based on LANDSAT spectral data.

We speculate the cause of rapid increase in dissolved iron concentration of the Amur river in the late 1990s were caused by melting of sporadic permafrost which resulted in the extension of redox condition in the upper part of the Amur river.

Free Research Field

地理学