Crab bioturbation significantly alters sediment microbial composition and function in an intertidal marsh

Abstract

Crabs are among the most important benthos in intertidal marshes. Numerous studies have shown that they can influence soil properties and soil-surface water exchange through bioturbation. However, little is still known about the effects of crab burrows on sediment microbes. In this study, we examined the effects of crab burrows on the community structure and interaction pattern of soil microbes in sediments in an intertidal marsh of the Yellow River Delta, north China using high-throughput sequencing and co-occurrence network analyses. Results showed that crab bioturbations altered soil microbial community composition both within the fungal and bacterial communities. Network analyses results indicated that the modularity of fungal networks decreased after crab bioturbation. Further, bacterial and fungal functional predictions indicated the relative abundances were significantly lower for fungal saprotrophs and saprotroph-pathotrophs in the soil mound sediment, while significantly higher for bacterial chemoheterotrophs and aerobic chemoheterotrophic in the burrow wall sediment. Our results demonstrate that crab bioturbation can modify the microbial community structure and function, and thus nutrient cycling through degradation of organic matter, a key ecosystem processes in intertidal marsh.