红树根系分泌物与微塑料联合调控对沉积物微生物群落特征的影响OA

Plastic pollution has become increasingly severe in mangrove ecosystems.To examine the interactive effects of mangrove root exudates(RE)and microplastics(MPs)on the microbial communities of both the plastisphere and sediments,a laboratory microcosm experiment was conducted.Two types of MPs,polyethylene(PE-MPs)and biode-gradable polylactic acid(PLA-MPs),together with RE from two mangrove species,were added to sediments and incu-bated for 45 days.After incubation,the structural characteristics of microbial communities on MPs and in sediments under different treatments were analyzed using 16S rDNA high-throughput sequencing,and the key driving factors were identified.The results indicated that in mangrove systems,MPs form a distinct ecological niche,with significantly higher microbial community diversity on their surfaces compared to the surrounding sediments,and this feature was primarily determined by MPs polymer type rather than RE input.At the phylum level,the dominant phylum Desulfo-bacterota was less abundant on MPs(10.49%)than in sediments(20.12%),with RE enhancing its presence on PLA-MPs but reducing it on PE-MPs.As a typical sulfate-reducing microorganism,the Desulfobacterota-driven sulfur cycle in mangrove systems warrants further investigation.Proteobacteria were markedly enriched on MPs(27.78%),yet its sedimentary abundance declined with MPs addition.Actinobacteriota were more abundant in PE-MPs and associated sediments compared to PLA-MPs.At the genus level,In contrast,the relative abundance of Ketobacter on PE-MPs was 321.20 times higher than that on PLA-MPs,and was 3.89 times higher on PE-MPs with added RE than on those without.In terms of community stability,RE addition enhanced the complexity and stability of microbial co-occurrence networks in both the plastisphere and sediments,promoting cooperative interactions largely driven by Firmicutes.These results demonstrated that MPs type was a key factor regulating differential microbial colonization on the surfaces,while RE played a significant role in shaping microbial community structure and stability through resource input.Furthermore,the microbial community structures of both MPs and sediments were mainly driven by environmental factors such as salinity and dissolved organic carbon(DOC),with distinct driving patterns observed between the plastisphere and sediments.These results provide insights into the ecological impacts of MPs in mangrove systems under the influence of RE.