Microplastics and co-pollutant with ciprofloxacin affect interactions between free-floating macrophytes

Area of Science:

• Environmental Science
• Ecotoxicology
• Aquatic Botany

Background:

• Microplastic and antibiotic contamination pose growing threats to aquatic ecosystems.
• Limited understanding exists regarding the combined effects of microplastics and antibiotics on freshwater vascular plants and their interactions.

Purpose of the Study:

• To investigate the impact of polyethylene-microplastics and ciprofloxacin on the growth and physiology of Spirodela polyrhiza and Lemna minor.
• To assess the interactive effects of microplastics and ciprofloxacin on the competition and interactions between these two macrophyte species.

Main Methods:

• A mesocosm experiment was conducted using Spirodela polyrhiza and Lemna minor.
• Evaluated growth parameters (fresh weight, specific leaf area) and physiological indicators (photosynthetic pigments, malondialdehyde, catalase, soluble sugar).
• Assessed relative yield and competitiveness under different contamination scenarios.

Main Results:

• Microplastics alone did not significantly affect fresh weight or specific leaf area but induced species-specific physiological changes.
• Ciprofloxacin adversely impacted plant growth and physiology, while microplastics partially mitigated its toxicity.
• Microplastics and co-pollutants altered macrophyte competitiveness and interactions by affecting their physiology and growth.

Conclusions:

• Species-specific responses to microplastics and co-pollutants can influence macrophyte population dynamics, community structure, and ecosystem functioning.
• Microplastics can modify the behavior and toxicity of other contaminants, indirectly affecting plant interactions and community structure.
• This study provides novel insights into the effects of microplastics and co-pollutants on free-floating macrophyte interactions, informing freshwater ecosystem management.