Dr. Katsuaki Watanabe
STAMレビュー論文
著者名：
Katsuaki Watanabe
所属と連絡先（メールアドレス、住所、電話、）:
Department of Earth and Planetary Science, Graduate School of Science, the University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 JAPAN
Tel.: +81 3 5841 4019
E-mail address: kwatanabe@eps.s.u-tokyo.ac.jp
Title:
Biological weathering, mineralization and soil formation by lichens.
概要：
(1) 地衣類（lichen）とは。菌類と藻類との共生生物であること、世界中に分布し、とくに植生の乏しい劣悪な環境にも生育可能であること。
(2) 地衣類による岩石風化作用。粘土層の形成、溶出による微小孔の形成について。
(3) 地衣類によるバイオミネラリゼーション（生物鉱化作用）。Fe酸／水酸化物、Ca蓚酸塩の形成について。
(4) 地衣類による土壌前駆物質の形成。粘土および風化層、微小孔、FeやCa鉱物、有機物、水分などを、合わせて保持できる地衣類-岩石接触面の特性について。
(5) 植生回復の第一段階としての地衣類作用の意義。
Nature Cluster WEBページ
1) 研究テーマ：
Biological weathering and biomineralization occurring at lichen-rock interface
2) 研究の概要：
We can find a widespread of moss-like creatures on old stone monuments and buildings (Fig.1). They are lichens, mini-ecosystems consisting of at least two organisms; a fungus and a photosynthetic partner. Fungi, algae and/or cyanobacteria associate in many different ways in lichens. This association or symbiosis is not usually a simple mixture. Lichens are widespread and the algal cells appear to be healthy inside the lichens. Lichens can be classified into three morphologically; crustose (flat, see Fig.1), foliose (leafy) and fruticose (branched).
Lichens cause corrosion and fragmentation of rocks, and crystallization of secondary minerals in the lichen-rock interface (Fig.2). As a result, thin weathered-rock layers consisting of clay minerals, corrosion pits, Fe oxy/hydroxides and Ca oxalates are formed around the interface, and they are kept without erosion. The mixture of these secondary minerals and lichen body (organic matter) can be considered as a soil precursor.
The formation of soil precursor is significant in the case of crustose lichens, which have large interface between lichen body and rocks. I study the soil formation mechanism affected with crustose lichen, and elemental behavior during it.
Fig.1. Crustose lichens growing on granite.
Fig.2. Biophysical and biochemical weathering of biotite by a crustose lichen in the lichen-granite interface (Backscattered electron image).
3) URL:
http://www-gbs.eps.s.u-tokyo.ac.jp/kogure/
4) Name:
WATANABE, Katsuaki
5) Affiliation:
Department of Earth and Planetary Science, Graduate School of Science, the University of Tokyo
6) e-mail:
kwatanabe@eps.s.u-tokyo.ac.jp
