We can't find the internet
Attempting to reconnect
Something went wrong!
Hang in there while we get back on track
Spatial patterns of microplastic accumulation and microbial degradation function along coastal wetland tidal gradients
Summary
This study of a Chinese tidal estuary found that microplastics accumulate most heavily in the high-tide zone, particularly in surface soils, with fragments (72–79%) and small particles under 100 µm dominating. Soil nitrogen chemistry emerged as the strongest factor associated with microplastic distribution, and microbial degradation potential varied across tidal zones. Understanding where microplastics pool in coastal wetlands — and how soil chemistry controls this — helps predict long-term contamination risks for both wetland ecosystems and the marine environments they connect to.
Coastal wetlands are key transition zones for microplastics (MPs) transporting from land to sea, where MPs can accumulate and persist, posing long-term ecological risks. This study examined MPs abundance patterns and microbial degradation-related functional potential across high-tidal (including vegetation area), middle-tidal, and low-tidal zones in the Qiantang River estuary, a pronounced dynamic tidal system, connecting the mainland to the East China Sea. MPs abundance increased with tidal elevation (low < middle < high-tidal zone), with peak concentrations in topsoil (low- and high-tidal zones) or the 10-20 cm layer (middle-tidal zone). MPs were mainly fragments (72.45%-79.47%) and 10-100 μm in size (81.89%). Partial least squares path modeling (PLS-PM) identified soil physicochemical properties, particularly nitrogen-related parameters (NH4+-N and NO3--N), as the main factors associated with MPs distribution, followed by spatial factors (tidal zone and depth). Microbial degradation-related functional potential inferred from microbial community composition exhibited a significant negative association with MPs abundance. Vegetation within the tidal zone also influenced MPs patterns: rhizosphere soil (RS) had significantly higher MPs abundance (2633-3284 n g-1) and smaller particle sizes than bulk soils (1009-1536 n g-1), coinciding with increased MPs-degrading bacteria (e.g., Xanthomonadales, especially Stenotrophomonas) in the RS. These findings highlight the combined effects of tidal dynamics and rhizosphere interactions on MPs fate within coastal wetlands, providing crucial insights for the management of MPs pollution in these ecologically sensitive areas.