Plastic pollution primarily affects terrestrial ecosystems by altering the physical and chemical properties of soil, impacting crucial functions like water movement and the interactions between plants and soil.
Microplastics, which are tiny plastic particles, can accumulate in soils. Their presence leads to physico-chemical changes on soil texture and structure (Bergmann et al., 2016, Zheng et al., 2016). This means the way soil particles clump together and the overall feel and composition of the soil can be changed by the addition of plastic fragments.
Impacts on Soil Properties
The changes brought about by microplastics in the soil have significant consequences:
- Altered Soil Texture: Microplastics mix with natural soil components (sand, silt, clay, organic matter), changing the overall composition.
- Modified Soil Structure: They can interfere with the formation of stable soil aggregates (clumps of soil particles), potentially leading to:
- Reduced pore space, affecting air and water flow.
- Changes in soil density.
Consequences for Ecosystem Functioning
These alterations in soil properties have cascading effects throughout the terrestrial ecosystem:
- Water Cycling: Changes in soil texture and structure directly impact how water infiltrates the soil, how much water the soil can hold, and how water moves through the soil layers. This is consequential for water cycling within the ecosystem (Bergmann et al., 2016, Zheng et al., 2016), affecting plant water availability and groundwater recharge.
- Ecosystem Functioning: Soil health is fundamental to terrestrial ecosystems. When soil structure and water dynamics are compromised, it affects nutrient cycling, decomposition, and the habitat for soil organisms. This impacts overall ecosystem functioning (Bergmann et al., 2016, Zheng et al., 2016).
- Plant-Soil Feedbacks: The relationship between plants and the soil they grow in is intricate, involving nutrient exchange, microbial communities, and physical support. Changes in soil due to microplastics can disrupt these interactions, affecting diverse plant-soil feedbacks (Bergmann et al., 2016, Zheng et al., 2016), which are crucial for plant growth, health, and species composition.
Practical Examples of Impacts:
- Reduced crop yield in agricultural lands due to poor soil structure and water retention.
- Decreased biodiversity of soil invertebrates and microorganisms essential for soil health.
- Increased risk of soil erosion if soil aggregates become less stable.
Mitigating the Impact
Addressing plastic pollution requires action across multiple fronts:
- Reduce Plastic Use: Minimize single-use plastics and choose sustainable alternatives.
- Improve Waste Management: Enhance collection, sorting, and recycling systems to prevent plastics from entering the environment.
- Cleanup Efforts: Remove existing plastic debris from terrestrial environments.
- Research and Innovation: Develop biodegradable plastics and methods for remediating contaminated soils.
- Policy and Regulation: Implement policies to limit plastic production and improve end-of-life management.
By altering the very foundation of terrestrial life – the soil – plastic pollution poses a significant threat to the health and functioning of ecosystems, impacting everything from water availability to plant growth.
