Tracing gypsiferous White Sands aerosols in the shallow critical zone in the northern Sacramento Mountains, New Mexico using Sr/Ca and 87Sr/86Sr ratios
Tracing gypsiferous White Sands aerosols in the shallow critical zone in the northern Sacramento Mountains, New Mexico using Sr/Ca and 87Sr/86Sr ratios
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DOI：
10.1016/j.geoderma.2020.114387
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发表时间：
2020-08
期刊：
影响因子：
6.1
通讯作者：
P. Rea;Lin Ma;T. Gill;J. Gardea-Torresdey;C. Tamez;Lixin Jin
中科院分区：
文献类型：
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作者：
P. Rea;Lin Ma;T. Gill;J. Gardea-Torresdey;C. Tamez;Lixin Jin
白沙(美国新墨西哥州)散发出具有独特化学和矿物学特征的石膏粉尘，为研究其装载和区域运动提供了机会。本研究追踪了白沙粉尘对萨克拉门托山脉北部顺风向山地土壤的输入，并提供了更好的了解石膏粉尘对活跃临界区生物可利用植物养分来源的影响。从活性最强的石灰岩、混合石灰岩、闪长岩，到活性最低的砂岩，以及不同的大气端元(降雨、区域粉尘和白沙石膏)，在不同风化性的基岩上收集了四种土壤剖面。在萨克拉门托山脉观测到的年干沉积速率约为11微克/米−2yr−1，比迎风奇瓦瓦沙漠盆地的干沉积速率低一个数量级，更接近较低海拔的尘埃源。整体土壤的元素化学、Ca/Sr和87Sr/86Sr主要受基岩控制，并受到碳酸盐基质化学风化的影响，而大气输入仅在最不活跃的砂岩上的浅层土壤中通过Ca、Sr和Na的附加剖面才能检测到。白砂尘虽然只占土壤整体质量的一小部分，但与湿沉降一起，控制着植物的Ca/Sr和87Sr/86Sr比值以及土壤的水分可淋溶部分。来自白沙的颗粒，主要是石膏，非常易溶，在萨克拉门托山脉的土壤中很快溶解，但在不透水的基岩-土壤界面重新沉淀。虽然植物中钙和锶的绝对浓度在四个地点和不同的当地植物类型之间差异很大，但锶/钙比值在很大程度上受植物类型的控制，因此根的深度。这项研究强调了即使在半湿润的环境中，区域沙尘和降雨在装载养分方面的重要性。
White Sands (New Mexico, USA) emits gypsum dust with a unique chemical and mineralogical signature, providing an opportunity to investigate its loading and regional movement. This study tracked White Sands dust input to montane soils downwind in the northern Sacramento Mountains, and provided better understanding of the effects of gypsum dust on sources of bioavailable plant nutrients in an active critical zone. Four soil profiles were collected over bedrocks of different weatherabilities, from the most reactive limestone, mixed limestone, diorite, to the least reactive sandstone, as well as different atmospheric end-members (rain, regional dust, and White Sands gypsum). Annual dry deposition rate observed at the Sacramento Mountains was approximately at 11 g m−2yr−1, up to an order of magnitude lower than those at the Chihuahuan Desert basins upwind and closer to dust sources at lower elevations. Elemental chemistry, Ca/Sr and87Sr/86Sr of bulk soils were mostly controlled by those of bedrocks and modified by chemical weathering over carbonate substrates, whereas the atmospheric input was only detectable in shallow soils over the least reactive sandstone through addition profiles of Ca, Sr and Na. Although only making up a small portion of a bulk soil in mass, White Sands dust, along with wet deposition, dominantly controlled the Ca/Sr and87Sr/86Sr ratios of plants and the water leachable fraction of the soils. Particles from White Sands, predominantly gypsum, were very soluble, and dissolved quickly in soils of the Sacramento Mountains but re-precipitated at the impermeable bedrock-soil interface. Although absolute concentrations of Ca and Sr in plants differed widely among four sites and among different local plant types, Sr/Ca ratios were largely controlled by plant type, and thus the rooting depth. This study highlighted the importance of regional dust and rainfall in loading nutrients even in a semi-humid environment.