TY - JOUR
T1 - Mechanistic insights into trace metal mobilization at the micro-scale in the rhizosphere of Vallisneria spiralis
AU - Li, Cai
AU - Ding, Shiming
AU - Chen, Musong
AU - Sun, Qin
AU - Zhang, Yi
AU - Ma, Xin
AU - Zhong, Zhilin
AU - Tsang, Daniel C.W.
AU - Wang, Yan
N1 - Funding Information:
This research work was financially supported by the National Key Research and Development Plan ( 2018YFA0903000 ), National Natural Science Foundation of China ( 41621002 , 41877492 and 51879083 ), CAS Interdisciplinary, Innovation Team, and Research instrument and equipment, and Development Project of the Chinese Academy of Sciences ( YJKYYQ20170016 ).
Publisher Copyright:
© 2021
PY - 2022/2/1
Y1 - 2022/2/1
N2 - Mobilization of trace metals in the rhizosphere of macrophytes is controlled by root-driven chemical changes, especially the steep gradients of O2 and pH from the rhizosphere to bulk sediments. Here, the O2 and pH dynamics, and the distribution of trace metal, in the rhizosphere of Vallisneria spiralis were obtained using planar optodes and diffusive gradients in thin films, respectively. Radial O2 loss (ROL) and acidification occurred on all visible roots of V. spiralis and exhibited highly spatiotemporal dynamics depending on the root growth and various environmental conditions. Trace metals showed different mobilization mechanisms in the rhizosphere. ROL and produced Fe(III) (oxyhydr)oxides decreased the mobility of Fe, As, Co, V and W in the rhizosphere. However, Mn, Ni and Cu exhibited greater mobility in the rhizosphere than bulk sediments as a result of the oxidation of metal sulfide and proton-induced dissolution of minerals. In particular, Co and Ni presented increased activity at the interface between rhizosphere and bulk sediment, which was attributed to the redox dissolution processes of Fe and Mn as a result of ROL and rhizosphere acidification. These results provide new insights into the roles of macrophyte root-induced O2 and pH changes in controlling trace metal mobility in sediments.
AB - Mobilization of trace metals in the rhizosphere of macrophytes is controlled by root-driven chemical changes, especially the steep gradients of O2 and pH from the rhizosphere to bulk sediments. Here, the O2 and pH dynamics, and the distribution of trace metal, in the rhizosphere of Vallisneria spiralis were obtained using planar optodes and diffusive gradients in thin films, respectively. Radial O2 loss (ROL) and acidification occurred on all visible roots of V. spiralis and exhibited highly spatiotemporal dynamics depending on the root growth and various environmental conditions. Trace metals showed different mobilization mechanisms in the rhizosphere. ROL and produced Fe(III) (oxyhydr)oxides decreased the mobility of Fe, As, Co, V and W in the rhizosphere. However, Mn, Ni and Cu exhibited greater mobility in the rhizosphere than bulk sediments as a result of the oxidation of metal sulfide and proton-induced dissolution of minerals. In particular, Co and Ni presented increased activity at the interface between rhizosphere and bulk sediment, which was attributed to the redox dissolution processes of Fe and Mn as a result of ROL and rhizosphere acidification. These results provide new insights into the roles of macrophyte root-induced O2 and pH changes in controlling trace metal mobility in sediments.
KW - Macrophytes
KW - Rhizosphere
KW - Rhizosphere acidification
KW - ROL
KW - Trace metal mobility
UR - http://www.scopus.com/inward/record.url?scp=85116592947&partnerID=8YFLogxK
U2 - 10.1016/j.scitotenv.2021.150735
DO - 10.1016/j.scitotenv.2021.150735
M3 - Journal article
C2 - 34606867
AN - SCOPUS:85116592947
SN - 0048-9697
VL - 806
JO - Science of the Total Environment
JF - Science of the Total Environment
M1 - 150735
ER -