Wang Bing, Liu Yangzheng, Wang Zihao, Zhang Qiuliang
Forestry College, Inner Mongolia Agricultural University, Hohhot 010019, China; Forest Ecosystem National Observation and Research Station of Greater Khingan Mountains in Inner Mongolia, Genhe 022350, China.
School of Ecology and Environment, Inner Mongolia University, 010021 Hohhot, China.
Sci Total Environ. 2024 Nov 10;950:175287. doi: 10.1016/j.scitotenv.2024.175287. Epub 2024 Aug 5.
Rare earth elements (REEs) are integral to numerous high-tech industries, yet their biogeochemical cycling within ecosystems remains inadequately characterized. Recently, phytoliths have been identified as potentially significant sinks for REEs; however, their role in the cycling of these elements has been underestimated. In this work, we investigate the accumulation of REEs in phytoliths (PhytREEs) within the Greater Khingan Mountains region, employing an optimized wet oxidation method combined with heavy liquid flotation to quantify PhytREEs contents in surface soils. The results revealed an elevation-dependent pattern of PhytREEs concentration, with heightened levels at higher altitudes and diminishing concentrations towards the eastern plains. The enrichment coefficient of PhytREEs (EC) was found to be approximately 2.7 %, indicative of a moderately selective sequestration process. The multivariate analysis indicated that terrain complexity, climatic patterns, soil texture, and organic matter significantly influence the uptake and storage of REEs in plants, subsequently affecting their partitioning in phytoliths. Among these factors, the complexation of REEs with organic matter emerged as a pivotal mechanism facilitating their immobilization within phytoliths. Soil characteristics also play a non-negligible role in modulating REEs dynamics. Our findings highlight the predominant influence of climate on PhytREE storage, suggesting that climatic variables are the primary drivers modulating the bioavailability and ultimate sequestration of REEs within phytoliths. This study enhances our understanding of the biotic-abiotic interplay in the sequestration of REEs and underscores the need to incorporate phytoliths into models of terrestrial REE cycling.
稀土元素（REEs）是众多高科技产业不可或缺的组成部分，然而它们在生态系统中的生物地球化学循环仍未得到充分表征。最近，植硅体已被确定为稀土元素潜在的重要汇；然而，它们在这些元素循环中的作用一直被低估。在这项工作中，我们研究了大兴安岭地区植硅体中稀土元素（PhytREEs）的积累情况，采用优化的湿氧化法结合重液浮选法来量化表层土壤中的PhytREEs含量。结果显示，PhytREEs浓度呈现出随海拔升高而增加的模式，海拔越高含量越高，向东部平原浓度逐渐降低。发现PhytREEs的富集系数（EC）约为2.7%，表明存在适度的选择性固存过程。多变量分析表明，地形复杂性、气候模式、土壤质地和有机质显著影响植物对稀土元素的吸收和储存，进而影响它们在植硅体中的分配。在这些因素中，稀土元素与有机质的络合作用成为促进其在植硅体内固定的关键机制。土壤特性在调节稀土元素动态方面也起着不可忽视的作用。我们的研究结果突出了气候对PhytREEs储存的主要影响，表明气候变量是调节稀土元素在植硅体内生物有效性和最终固存的主要驱动因素。这项研究增进了我们对稀土元素固存过程中生物与非生物相互作用的理解，并强调有必要将植硅体纳入陆地稀土元素循环模型。
