Biogeochemical Consequences of Infaunal Activities

Abstract : Activities of sedimentary infauna have significant consequences on overall sedimentary diagenesis. Infauna directly participate in sedimentary processes by organic matter metabolization coupled to aerobic respiration and metabolite excretion. In addition, they indirectly influence the diagenetic pathways by changing the transport regimes of dissolved and particulate species as well as by modifying microbial habitats. The couplings between infaunal activities and their biogeochemical consequences have been studied in recent years, but many of the results and conclusions remain site and species-specific due to the diverse and highly intenrelated ways in which sedimentary infauna interact with the transport, reaction, and microbial regimes. A generalized understanding of infauna-influenced sedimentary systems will require (1) a systematic classification of the infauna-sediment interaction mechanisms and (2) a comprehensive model framework that incorporates all known effects of infauna-sediment interactions associated with transport, reaction, and microbial regimes.