Direct contribution of invertebrate holobionts to methane release from coastal sediments

Sediment macrofauna play a vital role in sustaining aquatic food webs and biogeochemical cycles. Previous research demonstrated that bioturbation indirectly affects methane (CH4) dynamics through mobilization of porewater and alteration of microbial processes in the surrounding sediment. However, little is known on the direct contribution of macrofauna holobionts (the assemblage of invertebrate host and associated microbiome) to biogeochemical fluxes. Here, we investigated how 19 taxa of macrofauna holobionts, from different estuarine habitats spanning 40(degrees) to 63(degrees) latitude, directly contribute to CH(4 )fluxes. Deep burrowing infauna and deposit feeders were responsible for the highest CH4 production, whereas epifauna and filter feeders promoted oxidative CH4 consumption. Among the different environmental parameters, salinity was inversely correlated with CH4 production by macrofauna holobionts, with the process suppressed at high salinity (>= 33). This study provides empirical evidence on how functional traits and environmental factors influence sediment invertebrates' contribution to CH4 fluxes.

Automated summary

Sediment macrofauna, specifically holobionts, play an important role in sustaining aquatic food webs and biogeochemical cycles. This study investigates the direct contribution of different taxa of macrofauna holobionts to methane (CH4) fluxes. The results show that deep burrowing infauna and deposit feeders contribute to the highest CH4 production, while epifauna and filter feeders promote oxidative CH4 consumption. Salinity was found to inversely correlate with CH4 production by macrofauna holobionts.