Evidence of microplastic (MP) pollution in Antarctic terrestrial environments reinforces concerns about its potential impacts on soil, which plays a major role in ecological processes at ice-free areas. We investigated the effects of two common MP types on soil physicochemical properties and microbial responses of a marine terrace from Fildes Peninsula (King George Island, Antarctica). Soils were treated with polyethylene (PE) fragments and polyacrylonitrile (PAN) fibers at environmentally relevant doses (from 0.001% to 1% w w), in addition to a control treatment (0% w w), for 22 days in a pot incubation experiment under natural field conditions. The short-term impacts of MPs on soil physical, chemical and microbial attributes seem interrelated and were affected by both MP dose and type. The highest PAN fiber dose (0.1%) increased macro and total porosity, but decreased soil bulk density compared to control, whereas PE fragments treatments did not affect soil porosity. Soil respiration increased with increasing doses of PAN fibers reflecting impacts on physical properties. Both types of MPs increased microbial activity (fluorescein diacetate hydrolysis), decreased the cation exchange capacity but, especially PE fragments, increased Na saturation. The highest dose of PAN fibers and PE fragments increased total nitrogen and total organic carbon, respectively, and both decreased the soil pH. We discussed potential causes for our findings in this initial assessment and addressed the need for further research considering the complexity of environmental factors to better understand the cumulative impacts of MP pollution in Antarctic soil environments.

中文翻译：

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聚乙烯和聚丙烯腈微塑料对南极洲海洋阶地环境土壤理化性质和微生物活性的短期影响

南极陆地环境中微塑料（MP）污染的证据加剧了人们对其对土壤潜在影响的担忧，土壤在无冰地区的生态过程中发挥着重要作用。我们研究了两种常见 MP 类型对菲尔德斯半岛（南极洲乔治王岛）海洋阶地土壤理化性质和微生物反应的影响。除了对照处理（0% ww）之外，还用环境相关剂量（0.001% 至 1% ww）的聚乙烯 (PE) 碎片和聚丙烯腈 (PAN) 纤维对土壤进行处理，在盆栽实验中进行 22 天。自然场地条件。 MP 对土壤物理、化学和微生物属性的短期影响似乎是相互关联的，并且受到 MP 剂量和类型的影响。与对照相比，最高的PAN纤维剂量（0.1%）增加了宏观和总孔隙度，但降低了土壤容重，而PE碎片处理并不影响土壤孔隙度。土壤呼吸随着 PAN 纤维剂量的增加而增加，反映了对物理特性的影响。两种类型的 MP 都会增加微生物活性（荧光素二乙酸酯水解），降低阳离子交换能力，但尤其是 PE 片段会增加 Na 饱和度。最高剂量的 PAN 纤维和 PE 碎片分别增加了总氮和总有机碳，并且都降低了土壤 pH 值。我们讨论了初步评估中发现的潜在原因，并考虑到环境因素的复杂性，解决了进一步研究的必要性，以更好地了解南极土壤环境中 MP 污染的累积影响。