Mesocosm-based assessment of halophyte planting on microbial communities and potential blue carbon in tidal flats

초록

Halophytes enhance carbon sequestration rates in coastal ecosystems through long-term plant litter deposition and burial. This study focuses on the short-term effects of planted halophytes on soil TOC and microbial community structure. Variations in halophyte species, planting method, soil depth, and sampling month were examined in artificially constructed testbeds along the western coast of the Republic of Korea. Three different species of halophytes -Phragmites australis (PA), Suaeda malacosperma (SM), and Suaeda japonica (SJ)-were planted on testbeds, with three different planting methods. Analysis of microbial community structure revealed the dominant phyla of each halophyte species. In PA soils, Proteobacteria (25.63%), Actinobacteriota (15.27%), and Planctomycetota (11.61%) were predominant, while SM soils were dominated by Proteobacteria (28.73%), Planctomycetota (17.27%), and Acidobacteriota (12.02%). In SJ soils, Proteobacteria (18.05%), Campylobacterota (16.56%), and Chloroflexi (12.64%) were most abundant. Beta diversity analysis indicated that halophyte species and soil depth were the principal drivers of microbial variation, whereas planting method had negligible influence. Soil TOC content (%) increased most notably in SJ plots (by 0.12%p), compared to marginal increases in PA (0.01%p) and SM (0.02%p) plots. Core taxa analysis through LEfSe and network community analysis consistently exhibited Sphingomonas, Candidatus Entotheonella, and Sulfurovum as core taxa of PA, SM and SJ groups, respectively. Collectively, the findings indicate that among the three tested halophyte species, S. japonica is the most effective candidate for enhancing blue carbon accumulation in coastal tidal flat environments.

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