Lozano Yudi M, Lehnert Timon, Linck Lydia T, Lehmann Anika, Rillig Matthias C
Plant Ecology, Institute of Biology, Freie Universität Berlin, Berlin, Germany.
Berlin-Brandenburg Institute of Advanced Biodiversity Research, Berlin, Germany.
Front Plant Sci. 2021 Feb 16;12:616645. doi: 10.3389/fpls.2021.616645. eCollection 2021.
Microplastics may enter the soil in a wide range of shapes and polymers. However, little is known about the effects that microplastics of different shapes, polymers, and concentration may have on soil properties and plant performance. To address this, we selected 12 microplastics representing different shapes (fibers, films, foams, and fragments) and polymers, and mixed them each with soil at a concentration of 0.1, 0.2, 0.3, and 0.4%. A phytometer () grew in each pot during 4 weeks. Shoot, root mass, soil aggregation, and microbial activity were measured. All shapes increased plant biomass. Shoot mass increased by ∼27% with fibers, ∼60% with films, ∼45% with foams, and by ∼54% with fragments, as fibers hold water in the soil for longer, films decrease soil bulk density, and foams and fragments can increase soil aeration and macroporosity, which overall promote plant performance. By contrast, all shapes decreased soil aggregation by ∼25% as microplastics may introduce fracture points into aggregates and due to potential negative effects on soil biota. The latter may also explain the decrease in microbial activity with, for example, polyethylene films. Our findings show that shape, polymer type, and concentration are key properties when studying microplastic effects on terrestrial systems.
微塑料可以多种形状和聚合物形式进入土壤。然而，对于不同形状、聚合物和浓度的微塑料对土壤性质和植物生长的影响，我们却知之甚少。为了解决这个问题，我们选取了12种代表不同形状（纤维、薄膜、泡沫和碎片）和聚合物的微塑料，并分别以0.1%、0.2%、0.3%和0.4%的浓度将它们与土壤混合。在每个花盆中种植了一种测定植物生长的植物达4周时间。测量了地上部分、根系质量、土壤团聚性和微生物活性。所有形状的微塑料均增加了植物生物量。纤维使地上部分质量增加了约27%，薄膜增加了约60%，泡沫增加了约45%，碎片增加了约54%，因为纤维能在土壤中保持水分更长时间，薄膜降低土壤容重，泡沫和碎片可增加土壤通气性和大孔隙度，总体上促进了植物生长。相比之下，所有形状的微塑料均使土壤团聚性降低了约25%，因为微塑料可能会在团聚体中引入断裂点，并且对土壤生物群有潜在负面影响。后者也可能解释了例如聚乙烯薄膜导致的微生物活性下降。我们的研究结果表明，在研究微塑料对陆地系统的影响时，形状、聚合物类型和浓度是关键特性。
