TY - JOUR
T1 - The effects of different doses of lanthanum-modified bentonite in combination with a submerged macrophyte (Vallisneria denseserrulata) on phosphorus inactivation and macrophyte growth
T2 - A mesocosm study
AU - Zhang, Xiumei
AU - Zhen, Wei
AU - Cui, Suzhen
AU - Wang, Sen
AU - Chen, Weiqi
AU - Zhou, Qiong
AU - Jeppesen, Erik
AU - Liu, Zhengwen
N1 - Publisher Copyright:
© 2024 Elsevier Ltd
PY - 2024/2
Y1 - 2024/2
N2 - The combination of chemical phosphorus (P) inactivation and submerged macrophyte transplantation has been widely used in lake restoration as it yields stronger effects than when applying either method alone. However, the dose effect of chemical materials on P inactivation when used in combination with submerged macrophytes and the influences of the chemicals used on the submerged macrophytes growth remain largely unknown. In this study, we investigated P inactivation in both the water column and the sediment, and the responses of submerged macrophytes to Lanthanum modified bentonite (LMB) in an outdoor mesocosm experiment where Vallisneria denseserrulata were transplanted into all mesocosms and LMB was added at four dosage levels, respectively: control (LMB-free), low dosage (570 g m−2), middle dosage (1140 g m−2), and high dosage (2280 g m−2). The results showed that the combination of LMB dosage and V. denseserrulata reduced TP in the water column by 32%–38% compared to V. denseserrulata alone, while no significant difference was observed among the three LMB treatments. Porewater soluble reactive P, two-dimensional diffusive gradient in thin films (DGT)-labile P concentrations, and P transformation in the 0–1 cm sediment layer exhibited similar trends along the LMB dosage gradient. Besides, LMB inhibited plant growth and reduced the uptake of mineral elements (i.e., calcium, manganese, iron, and magnesium) in a dosage-dependent manner with LMB. LMB may reduce plant growth by creating a P deficiency risk for new ramets and by interfering with the uptake of mineral elements. Considering both the dose effect of LMB on P inactivation and negative effect on macrophyte growth, we suggest a “small dosage, frequent application” method for LMB application to be used in lake restoration aiming to recover submerged macrophytes and clear water conditions.
AB - The combination of chemical phosphorus (P) inactivation and submerged macrophyte transplantation has been widely used in lake restoration as it yields stronger effects than when applying either method alone. However, the dose effect of chemical materials on P inactivation when used in combination with submerged macrophytes and the influences of the chemicals used on the submerged macrophytes growth remain largely unknown. In this study, we investigated P inactivation in both the water column and the sediment, and the responses of submerged macrophytes to Lanthanum modified bentonite (LMB) in an outdoor mesocosm experiment where Vallisneria denseserrulata were transplanted into all mesocosms and LMB was added at four dosage levels, respectively: control (LMB-free), low dosage (570 g m−2), middle dosage (1140 g m−2), and high dosage (2280 g m−2). The results showed that the combination of LMB dosage and V. denseserrulata reduced TP in the water column by 32%–38% compared to V. denseserrulata alone, while no significant difference was observed among the three LMB treatments. Porewater soluble reactive P, two-dimensional diffusive gradient in thin films (DGT)-labile P concentrations, and P transformation in the 0–1 cm sediment layer exhibited similar trends along the LMB dosage gradient. Besides, LMB inhibited plant growth and reduced the uptake of mineral elements (i.e., calcium, manganese, iron, and magnesium) in a dosage-dependent manner with LMB. LMB may reduce plant growth by creating a P deficiency risk for new ramets and by interfering with the uptake of mineral elements. Considering both the dose effect of LMB on P inactivation and negative effect on macrophyte growth, we suggest a “small dosage, frequent application” method for LMB application to be used in lake restoration aiming to recover submerged macrophytes and clear water conditions.
KW - Lake restoration
KW - Lanthanum modified bentonite
KW - Mineral elements uptake
KW - Phosphorus
KW - Submerged macrophyte
UR - http://www.scopus.com/inward/record.url?scp=85181872872&partnerID=8YFLogxK
U2 - 10.1016/j.jenvman.2024.120053
DO - 10.1016/j.jenvman.2024.120053
M3 - Journal article
C2 - 38211429
AN - SCOPUS:85181872872
SN - 0301-4797
VL - 352
JO - Journal of Environmental Management
JF - Journal of Environmental Management
M1 - 120053
ER -