Flooding patterns shape microbial community in mangrove sediments

BackgroundMangrove ecosystems located in the tropics and subtropics, are crucial for regulating global weather patterns and sequestering carbon. However, they face threats from human activities like altered water flow and deforestation. While the symbiotic relationship between mangrove trees and surrounding microbes are essential for their survival, the impact of human activity on these microbial communities remains incompletely understood. We investigated how microbial communities change in degraded mangrove ecosystems due to loss of hydrologic connectivity, aiming to elucidate consequences and inform restoration strategies. MethodsEmploying 16S rRNA sequencing, we analyzed samples of sediment cores from conserved, moderately degraded, and degraded mangrove sites across dry and flood seasons at three sediment depths. ResultsOur analysis identified 11,469 Amplicon Single Variant (ASVs), revealing diversity loss correlated with degradation levels. Notably, we observed shifts in microbial diversity within sediment layers, with conserved sites dominated by Vibrionaceae in upper layers, potentially indicating urban contamination. In moderate-degradation sites, seasonal patterns emerged, with Halomonas and Marinomonas dominating the dry season and Exiguobacterium thriving during flooding. Interestingly, a community mainly composed of Firmicutes persisted across all degradation scenarios in deeper sediment layers, suggesting potential for ecosystem restoration. Our findings provide insights into microbial responses to human-induced stressors and highlight the role of core microbial communities in guiding restoration efforts for degraded mangrove ecosystems.