Towards an ecology of soil microplastics

Helmberger, Maxwell S.; Tiemann, Lisa K.; Grieshop, Matthew J.

doi:10.1111/1365-2435.13495

Cited by 154 publications

(76 citation statements)

References 140 publications

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“…As microplastics may come into the soil in different shapes 5 , polymer types 6 and concentrations, it is crucial to understand its effects on soil properties and plant performance, especially as the use of plastic is increasing worldwide. Our findings provide empirical evidence that in the short term, microplastics of different shapes and polymers increase shoot and root biomass, but negatively affect soil properties as aggregation and microbial activity.…”

Section: Testing the Microplastic Shape-related Hypothesismentioning

confidence: 99%

“…Microplastics (< 5 mm) are increasingly reported in terrestrial systems, and due to slow turnover, may be gradually increasing through additions including soil amendments, plastic mulching, irrigation, flooding, atmospheric input and littering or street runoff [1][2][3][4] . As a result of their manufacturing origin, environmental degradation and intended use, these particles occur in many shapes, and cover a high physical and chemical diversity 5,6 .…”

Section: Introductionmentioning

confidence: 99%

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Microplastic shape, concentration and polymer type affect soil properties and plant biomass

Lozano

Lehnert

Linck

et al. 2020

Preprint

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Microplastics are an increasing concern in terrestrial systems. These particles can be incorporated into the soil in a wide range of shapes and polymers, reflecting the fact that manufacturers produce plastics in a variety of physical and chemical properties matching their intended use.Despite of this, little is known about the effects that the addition into the soil of microplastics of different shapes, polymer type and concentration levels may have on soil properties and plant performance.To fill this gap, we selected four microplastic shapes: fibers, films, foams and fragments; and for each shape we selected three microplastics made of one of the following polymers: polyester, polyamide, polypropylene, polyethylene, polyethylenterephthalat, polyurethane, polystyrene and polycarbonate. In a glasshouse experiment, each microplastic was added to a soil from a dry grassland at a concentration of 0.1%, 0.2%, 0.3% and 0,4%. A carrot (Daucus carota) plant grew in each pot during four weeks. At harvest, shoot and root mass, soil aggregation and microbial activity were measured.Our results showed that all microplastic shapes increased shoot and root masses. As concentration increased, microfibers increased plant biomass probably as fibers may hold water in the soil for longer. In contrast, microfilms decreased biomass with concentration, likely because they can create channels in the soil that promote water evaporation affecting plant performance. All microplastic shapes decreased soil aggregation, probably since microplastics may introduce fracture points in the aggregates affecting their stability and also due to potential negative effects on soil biota. The latter may also explain the decrease in microbial activity with, for example, polyethylene films. Similar to plant biomass, microfilms decreased soil aggregation with increasing concentration.Our study tested the microplastic shape mediation and dissimilarity hypotheses, highlighting the importance of microplastic shape, polymer type and concentration when studying the effects of microplastics on terrestrial systems.

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Section: Testing the Microplastic Shape-related Hypothesismentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Microplastic shape, concentration and polymer type affect soil properties and plant biomass

Lozano

Lehnert

Linck

et al. 2020

Preprint

View full text Add to dashboard Cite

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“…In soils, it would not have been possible to achieve a general process understanding. The design of more realistic experimental setups with soils is challenging because currently there are only few data on MP contamination in soils and it is not clear whether the MP concentrations found to date in urban (0.3-67.5 g kg −1 ), riparian (0-0.055 g kg −1 ), and agricultural soils (0-42,960 particles kg −1 ) (Helmberger et al, 2019) lead to negative effects on soil biota. Due to detection limits, even less data is available in environmental samples for MP particles <10 µm (Haegerbaeumer et al, 2019) and thus for the ingestible size range of C. elegans.…”

Section: Discussionmentioning

confidence: 99%

Microplastics Effects on Reproduction and Body Length of the Soil-Dwelling Nematode Caenorhabditis elegans

Schöpfer

Menzel

Schnepf

et al. 2020

Front. Environ. Sci.

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Microplastics (MP) are pervasive in the environment. There is ample evidence of negative MP effects on biota in aquatic ecosystems, though little is known about MP effects in terrestrial ecosystems. Given numerous entry routes of MP into soils, soil organisms are likely to be exposed to MP. We compared potential toxicological effects of MP from (i) low-density polyethylene (LDPE) (mean diameter ± standard deviation: 57 ± 40 µm) and (ii) a blend of biodegradable polymers polylactide (PLA) and poly(butylene adipateco-terephthalate) (PBAT) (40 ± 31 µm) on the reproduction and body length of the soil-dwelling bacterivorous nematode Caenorhabditis elegans. Feed suspensions without (control) or with MP (treatments) at concentrations of 1, 10, and 100 mg MP L −1 were prepared and nematodes were exposed to those suspensions on agar plates until completion of their reproductive phase (∼6 days). Using Nile red-stained PLA/PBAT MP particles and fluorescence microscopy, we demonstrated the ingestion of MP by C. elegans into pharynges and intestines. Under MP exposure, nematodes had fewer offspring (up to 22.9%) compared to nematodes in the control group. This decline was independent on the plastic type. We detected a tendency toward greater decreases in offspring at higher concentrations. Despite hints of negative effects on nematode body length under MP exposure, we could not derive a consistent pattern. We conclude that in MP-contaminated soils, the reproduction of nematodes, central actors in the soil food web, can be affected, with potentially negative implications for key soil functions, e.g., the regulation of soil biogeochemical cycles.

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“…As microplastics may come into the soil in different shapes and polymer types (Helmberger et al, 2020), it is important to understand how different microplastic types may affect ecosystem functionality. However, our findings provide clear empirical evidence that microplastics in soil affect ecosystem multifunctionality of terrestrial ecosystems, a phenomenon that may be strongly affected in future scenarios of global change, as changes in water regime are projected to occur in many areas worldwide.…”

Section: Microplastic Fibers and Drought Effects On Ecosystem Multifumentioning

confidence: 99%

“…Microplastics are a group of polymer-based particles with a diameter under 5 mm (Hidalgo-Ruz et al, 2012), which occur in many shapes, and possess a high physical and chemical diversity (Helmberger et al, 2020. These particles can originate from many sources, including tire abrasion, the loss of fibers from synthetic textiles during washing, or the environmental degradation of larger plastic objects (Boucher & Friot, 2017).…”

Section: Introductionmentioning

confidence: 99%

Effects of Microplastics and Drought on Ecosystem Functions and Multifunctionality

Lozano

Aguilar‐Trigueros

Onandía

et al. 2020

Preprint

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Microplastics in soils have become an important threat for terrestrial systems, which can be exacerbated by drought as microplastics may affect soil water content. Thus, the interaction between these two factors may alter ecosystem functions such as litter decomposition, stability of soil aggregates, as well as functions related to nutrient cycling. Despite this potential interaction, we know relatively little about how microplastics, under different soil water conditions, affect ecosystem functions and ecosystem multifunctionality.To address this gap, we carried out a controlled-environment study using grassland plant communities. We applied the two factors microplastic fibers (absent, present) and soil water conditions (well-watered, drought), in all possible combinations in a factorial experiment. At harvest, we measured multiple ecosystem functions linked to nutrient cycling, litter decomposition, and soil aggregation and as terrestrial systems provide these functions simultaneously, we also assessed ecosystem multifunctionality.Our results showed that the interaction between microplastic fibers and drought affected ecosystem functions and multifunctionality. Overall, drought had negatively affected nutrient cycling by decreasing potential enzymatic activities and increasing nutrient leaching, while microplastic fibers had a positive impact on soil aggregation and nutrient retention by diminishing nutrient leaching. Microplastic fibers also impacted enzymatic activities, soil respiration and ecosystem multifunctionality, but importantly, the direction of these effects depended on soil water status (i.e., they decreased under well watered conditions, but tended to increase or had similar effects under drought conditions). Litter decomposition had a contrary pattern.Synthesis and applications. As soil water content is affected by climate change, our results suggest that areas with sufficiency of water would be negatively affected in their ecosystem functioning as microplastics increase in the soil; however, in areas subjected to drought, microplastics would have a neutral or slightly positive effect on ecosystem functioning.

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Towards an ecology of soil microplastics

Cited by 154 publications

References 140 publications

Microplastic shape, concentration and polymer type affect soil properties and plant biomass

Microplastic shape, concentration and polymer type affect soil properties and plant biomass

Microplastics Effects on Reproduction and Body Length of the Soil-Dwelling Nematode Caenorhabditis elegans

Effects of Microplastics and Drought on Ecosystem Functions and Multifunctionality

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