http://english.cas.cn/newsroom/research_news/earth/202503/t20250320_908332.shtml

https://www.pnas.org/doi/10.1073/pnas.2423957122

A research group led by Prof. DANG Fei from the CAS Institute of Soil Science and Prof. ZHONG Huan from Nanjing University, has uncovered a significant yet often overlooked consequence of microplastic pollution: its detrimental impact on photosynthesis—a critical process underpinning Earth’s primary productivity and food security.

Microplastics—defined as plastic debris smaller than 5 mm—contaminate environments from deep-sea sediments to mountain glaciers. Despite growing awareness of this environmental hazard, the effects of microplastics on photosynthesis at the ecosystem level have remained unclear.

By analyzing 3,286 records using meta-analysis and machine learning techniques, the researchers quantified the global decline in photosynthesis due to microplastic exposure. Their findings reveal that microplastics decrease photosynthetic efficiency by 7.05–12.12% across terrestrial plants, marine algae, and freshwater algae. These reductions translate to estimated annual global losses of 4.11–13.52% (109.73–360.87 MT·yr^-1) for key staple crops such as rice, wheat, and maize. In aquatic ecosystems, microplastic-induced photosynthesis inhibition is projected to cause net primary productivity (NPP) losses of 0.31–7.24% (147.52–3,415.11 MT C·yr^-1), leading to seafood production declines of 1.05–24.33 MT·yr^-1. These figures underscore the hidden yet profound threat that microplastic pollution poses to global food security.

Encouragingly, the study suggests a pathway for mitigation. The researchers estimate that a 13% decrease in environmental microplastic levels could reduce photosynthesis losses by approximately 30%, preventing global losses of 22.15–115.73 MT·yr^-1 in major crops and 0.32–7.39 MT·yr^-1 in seafood production.