Microplastic occurrence and effects on soil fungi and processes along land use gradients

我们生活在一个受塑料影响很大的世界，因为塑料在我们的日常生活中无处不在。因此，塑料已被发现在广泛的环境隔间，主要是作为微塑料，即小于5毫米的塑料片。在最初仅在海洋和水生系统中进行研究之后，土壤最近在微塑料方面受到关注，数据开始显示，这可能是一种相当普遍的土壤污染物，对土壤物理，化学和生物学参数。考虑到输入途径的范围，包括塑料垃圾，堆肥，空气沉积和道路，有充分的理由假设微塑料将存在于生物多样性勘探土壤中。我们的研究有两个主要目标：首先，我们想知道微塑料（存在和/或类型）是否可以跟踪土地使用强度，从而作为人类干预和活动的标志。为了解决这个问题，我们将对草原中所有150个EP的土壤进行采样，并使用最先进的提取和鉴定方法（傅立叶变换红外光谱显微镜）对其进行微塑料存在，类型和组成的分析。然后，我们可以将这些数据与土地利用强度（LUI）或其组成部分以及EP水平的一般土壤特性联系起来。其次，我们希望测试实验性微塑料添加在田间的效果，沿着土地利用梯度。我们将通过部署和重新采样（1年后）含有微塑料污染土壤的小网袋来实现这一点，这些网袋将被埋在草原的所有VP中（包含每个VP的土壤）。我们将为此使用的微塑料是聚酯纤维，我们之前已经证明它对土壤物理性质和土壤过程有明确和一致的影响。我们的响应变量包括与真菌相关的土壤过程（分解，土壤聚集）和土壤微生物多样性（真菌群落，由Illumina MiSeq高通量测序评估）。通过我们的实地实验，我们希望测试微塑料效应在土壤类型和环境背景以及土地利用强度之间的差异。所有实验项目将从现场移除，以确保勘探土壤不会受到持久污染。考虑到我们在现场只使用一种微塑料类型，并且微塑料污染是一个多方面的问题，我们还将进行一个小规模的补充实验室实验，在这个实验中，我们只使用一种土壤类型，但除了微纤维之外，还添加了一系列不同的微塑料类型。总的来说，这项研究将深入了解土壤中微塑料的丰度和影响，独特地利用探索站提供的丰富信息，同时为其他研究人员（例如合成项目）和利益相关者提供一个新的潜在响应变量。

We live in a heavily plastic-influenced world, as plastic is ubiquitous in our daily lives. As a consequence, plastic has been found in a wide range of environmental compartments, predominantly as microplastics, that is plastic pieces < 5 mm. After initially having been studied in marine and aquatic systems only, soils have come into focus much more recently in terms of microplastic, with data beginning to show that this may be a rather widespread contaminant of soils, with potential consequences for soil physical, chemical and biological parameters. Given the range of input pathways, which include plastic trash, compost, aerial deposition and roads, there is good reason to assume that microplastics will be present in Biodiversity Exploratory soils. Our research has two main goals: First, we want to know if microplastics (presence and/ or type) can track land use intensity, thus serving as a signature of human intervention and activity. To address this, we will sample soils from all 150 EPs in grassland and assay them for microplastic presence, type and composition using state-of-the-art methods of extraction and identification (Fourier-transform infrared spectroscopy microscopy). We can then link these data to land use intensity (LUI) or its components, as well as to general soil properties available at the EP-level.Second, we want to test the effects of experimental microplastic addition in the field, along the land use gradient. We will approach this with the deployment and re-sampling (after 1 yr) of small mesh bags containing microplastic- contaminated soil, which will be buried in all VPs in grassland (containing the soil from each VP). The microplastic we will use for this is polyester fibers, which we have previously shown to have clear and consistent effects on soil physical properties and soil processes. Our response variables include fungal-related soil processes (decomposition, soil aggregation) and aspects of soil microbial diversity (fungal communities, assessed by Illumina MiSeq high-throughput sequencing). With our field experiment, we hope to test how microplastic effects differ among soil type and environmental context, as well as land use intensity. All experimental items will be removed from the field, assuring that there is no lasting contamination of Exploratory soils. Given that we will only use one microplastic type in the field, and that microplastic pollution is a multifaceted issue, we will also conduct a small-scale, complementary lab experiment, in which we use just one soil type per Exploratory, but add a range of different microplastic types in addition to microfibers. Overall, this research will yield insights into microplastic abundance and effects in soils, making unique use of the wealth of information available for the Exploratories, while at the same time offering a new response variable of potential interest to other researchers (for example in synthesis projects), but also stakeholders.