Microplastics and heavy metals reshape mangrove rhizosphere microbiomes and compromise carbon fixation potential

Mangroves with developed root systems at the land–sea junction act as sinks for microplastics (MPs). Heavy metals (HMs), persistent contaminants in coastal ecosystems, coexist with MPs globally. However, the complex effects of MP–HM pollution on mangrove ecosystems remain unclear. Herein, the combin...

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Main Authors: Linglong Cao, Huifeng Xie, Ruikun Sun, Lei He, Zhenqing Dai, Chengyong Li
Format: Article
Language:English
Published: Elsevier 2025-09-01
Series:Ecotoxicology and Environmental Safety
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Online Access:http://www.sciencedirect.com/science/article/pii/S014765132501245X
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author Linglong Cao
Huifeng Xie
Ruikun Sun
Lei He
Zhenqing Dai
Chengyong Li
author_facet Linglong Cao
Huifeng Xie
Ruikun Sun
Lei He
Zhenqing Dai
Chengyong Li
author_sort Linglong Cao
collection DOAJ
description Mangroves with developed root systems at the land–sea junction act as sinks for microplastics (MPs). Heavy metals (HMs), persistent contaminants in coastal ecosystems, coexist with MPs globally. However, the complex effects of MP–HM pollution on mangrove ecosystems remain unclear. Herein, the combined effects of various MPs (polypropylene (PP), polyethylene (PE), polyamide (PA)) and 10 HM (Cr, Cu, Pb, Zn, Cd, Mn, Co, Hg, As, and Ni) on the rhizosphere microecology of the mangrove plant Avicennia. marina (Forssk.) Vierh. (A. marina) were determined. The combined pollution caused by MPs–HMs changes the rhizosphere microbial community structure of A. marina and decreases species richness and diversity. The relative abundance of dominant bacteria (Firmicutes) in the PP–HM exposure (PPz) group increased by 58 %, and that of ε-Proteobacteria decreased by 49 %, compared with those in the heavy metal exposure (Z) group. PP and PA in the sediment enriched Bacillales (12 %) and Sphingomonales (3.6 %), respectively. The following were the distinct responses to the combined MP–HM pollution by the rhizosphere bacterial community: (1) sensitivity, which changed rapidly within 7 d of exposure, (2) specificity, differential enrichment of bacterial communities under MP vs HM stress, and (3) persistent alterations in functional bacteria following exposure. MPs in the sediment changed the bacterial community structure of the rhizosphere sediment by selective enrichment of the microbial taxa with specific plastic degradation functions. Thus, the long-term coexistence of MPs–HMs and microbes in mangrove wetlands may subtly change the biogeochemical cycling processes in coastal ecosystems. This study indicates the ecological effects of MPs–HMs in the rhizosphere environment, which provides theoretical support and scientific basis for the study of biogeochemical cycles.
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publishDate 2025-09-01
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spelling doaj-art-d9070b64dddb4c48b60e79ad5d3e35332025-08-22T04:54:46ZengElsevierEcotoxicology and Environmental Safety0147-65132025-09-0130311890010.1016/j.ecoenv.2025.118900Microplastics and heavy metals reshape mangrove rhizosphere microbiomes and compromise carbon fixation potentialLinglong Cao0Huifeng Xie1Ruikun Sun2Lei He3Zhenqing Dai4Chengyong Li5School of Chemistry and Environment, Analyzing and Testing Center, Guangdong Ocean University, Zhanjiang 524088, PR ChinaSchool of Chemistry and Environment, Analyzing and Testing Center, Guangdong Ocean University, Zhanjiang 524088, PR ChinaSchool of Chemistry and Environment, Analyzing and Testing Center, Guangdong Ocean University, Zhanjiang 524088, PR China; Corresponding author.Shenzhen Institute of Guangdong Ocean University, Shenzhen 518108, PR ChinaSchool of Chemistry and Environment, Analyzing and Testing Center, Guangdong Ocean University, Zhanjiang 524088, PR ChinaSchool of Chemistry and Environment, Analyzing and Testing Center, Guangdong Ocean University, Zhanjiang 524088, PR China; Shenzhen Institute of Guangdong Ocean University, Shenzhen 518108, PR China; Corresponding author at: School of Chemistry and Environment, Analyzing and Testing Center, Guangdong Ocean University, Zhanjiang 524088, PR China.Mangroves with developed root systems at the land–sea junction act as sinks for microplastics (MPs). Heavy metals (HMs), persistent contaminants in coastal ecosystems, coexist with MPs globally. However, the complex effects of MP–HM pollution on mangrove ecosystems remain unclear. Herein, the combined effects of various MPs (polypropylene (PP), polyethylene (PE), polyamide (PA)) and 10 HM (Cr, Cu, Pb, Zn, Cd, Mn, Co, Hg, As, and Ni) on the rhizosphere microecology of the mangrove plant Avicennia. marina (Forssk.) Vierh. (A. marina) were determined. The combined pollution caused by MPs–HMs changes the rhizosphere microbial community structure of A. marina and decreases species richness and diversity. The relative abundance of dominant bacteria (Firmicutes) in the PP–HM exposure (PPz) group increased by 58 %, and that of ε-Proteobacteria decreased by 49 %, compared with those in the heavy metal exposure (Z) group. PP and PA in the sediment enriched Bacillales (12 %) and Sphingomonales (3.6 %), respectively. The following were the distinct responses to the combined MP–HM pollution by the rhizosphere bacterial community: (1) sensitivity, which changed rapidly within 7 d of exposure, (2) specificity, differential enrichment of bacterial communities under MP vs HM stress, and (3) persistent alterations in functional bacteria following exposure. MPs in the sediment changed the bacterial community structure of the rhizosphere sediment by selective enrichment of the microbial taxa with specific plastic degradation functions. Thus, the long-term coexistence of MPs–HMs and microbes in mangrove wetlands may subtly change the biogeochemical cycling processes in coastal ecosystems. This study indicates the ecological effects of MPs–HMs in the rhizosphere environment, which provides theoretical support and scientific basis for the study of biogeochemical cycles.http://www.sciencedirect.com/science/article/pii/S014765132501245XMicroplasticsHeavy metalsRhizosphere microenvironmentSedimentAvicennia marina
spellingShingle Linglong Cao
Huifeng Xie
Ruikun Sun
Lei He
Zhenqing Dai
Chengyong Li
Microplastics and heavy metals reshape mangrove rhizosphere microbiomes and compromise carbon fixation potential
Ecotoxicology and Environmental Safety
Microplastics
Heavy metals
Rhizosphere microenvironment
Sediment
Avicennia marina
title Microplastics and heavy metals reshape mangrove rhizosphere microbiomes and compromise carbon fixation potential
title_full Microplastics and heavy metals reshape mangrove rhizosphere microbiomes and compromise carbon fixation potential
title_fullStr Microplastics and heavy metals reshape mangrove rhizosphere microbiomes and compromise carbon fixation potential
title_full_unstemmed Microplastics and heavy metals reshape mangrove rhizosphere microbiomes and compromise carbon fixation potential
title_short Microplastics and heavy metals reshape mangrove rhizosphere microbiomes and compromise carbon fixation potential
title_sort microplastics and heavy metals reshape mangrove rhizosphere microbiomes and compromise carbon fixation potential
topic Microplastics
Heavy metals
Rhizosphere microenvironment
Sediment
Avicennia marina
url http://www.sciencedirect.com/science/article/pii/S014765132501245X
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