The importance of blue carbon as a food source to oysters (Saccostrea cucullata) inside a tropical pristine Australian estuary

Abstract

This study investigated the importance of blue carbon (carbon captured from the atmosphere by algae, mangrove and seagrass leaves) as a component of particulate organic matter (POM) along the pristine King George River (Kimberley region, Australia), and how this modulates the diet of common suspension feeding bivalves (Mussels: Brachidontes sp. and Oysters: Saccostrea cucullata). These species utilise a range of different carbon sources (e.g., mangrove and seagrass detritus and plankton), which dictate the composition of locally available POM), which could then be used to evaluate shifts in consumer diet away from blue carbon within the estuary, to an increasing reliance on marine phytoplankton in offshore areas. The differences in δ13C of different organs (i.e., mantle, gill and adductor muscle) of oysters further affirm a greater discrepancy between ‘slow-turnover’ muscle and ‘fast-turnover’ gill and mantle tissue at offshore sites, when compared to inner estuarine sites.