The role of bio-geomorphic feedbacks in shaping microplastic burial in blue carbon habitats

• Published in: The Science of the total environment Vol. 861; p. 160220
• Main Authors: Xu, Nanhao, Zhu, Zhenchang, Li, Shaorui, Ouyang, Xiaoguang, Zhu, Qin, Gao, Weilun, Cai, Yanpeng, Yang, Zhifeng
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 25-02-2023
• Subjects: Burial; Carbon; Ecosystem; Environmental Monitoring; Feedback; Geologic Sediments; Mangroves; Microplastics; Plastics; Sediment erosion; Water Pollutants, Chemical - analysis; Waves; Burial; Mangroves; Microplastics; Sediment erosion; Waves
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2022.160220

Coastal sediments are considered as hotspots of microplastics (MPs), with substantial MPs stocks found in blue carbon habitats such as mangroves and tidal marshes, where wave-damping vegetation reduces sediment erosion and enhances accretion. Here, we examined the effects of such bio-geomorphic feedbacks in shaping MPs burial, through a year-round field study in a mangrove habitat along the coast of South China. The results revealed that MPs abundance decreased significantly with the increase of cumulative sediment erosion as the strength of bio-geomorphic feedbacks declined. More shapes and colors of MPs were found at locations with weaker waves and less sediment erosion, where the average particle size was also higher. Our findings highlight the importance of bio-geomorphic feedbacks in affecting both the abundance and characteristics of the buried MPs. Such knowledge extends our understanding of MPs transport and burial from the perspective of bio-geomorphology, which is essential to assess and predict MPs accumulation patterns as well as its impacts on ecosystem functioning of the blue carbon habitats.
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•Microplastics abundance in coastal sediments is limited by wave-induced erosion.•Wave reduction by vegetation increases microplastics burial in coastal sediments.•Where waves were lower, the average particle size of microplastics was higher.