An epibiotic association between burrowing and sessile bivalves on the Amazon continental shelf: implications for ecological facilitation in sediment-dominated environments

Jonata Arruda Francisco , Flavio de Almeida Alves-Júnior, Karolina Ferreira Rodrigues, José Carlos Nascimento Barros, Jonathan Stuart Ready

From the perspective of ecological facilitation theory, we report an epibiotic association between two mollusk species with contrasting lifestyles, Chama macerophylla Gmelin, 1791 (sessile) and Tucetona pectinata (Gmelin, 1791) (burrowing), on the Amazon continental margin. Specimens were collected using a Van Veen dredge near the shelf break and in the vicinity of AP3 blocks recently offered for offshore oil exploration. The observed interaction suggests that semi-infaunal bivalves may act as mobile hard substrates, facilitating the establishment of sessile organisms and increasing habitat heterogeneity in soft-bottom environments. This record provides a baseline for future environmental monitoring of ecological interactions in the region.