 The study examines the effect of sand amendments on microbial communities and salt marsh sediments at varying inundation regimes, finding that sand amendments drastically modified the bacterial communities, decreasing richness and diversity. The dominant sulfur cycling bacterial community was replaced by one dominated by iron oxidizers and aerobic heterotrophs, with higher CO2 flux. The relative abundance of iron oxidizing zetoproteobacteria increased in the sand amended sediments, possibly contributing to acidification. The study suggests that analyzing microbial community composition could be a useful tool to monitor climate adaptation and restoration efforts. This article was authored by Francois Thomas, James T. Morris, Kathleen Wigand, and others.