Feeding biology of a habitat forming antipatharian in the Azores Archipelago

Benthic suspension feeders have developed a variety of feeding strategies and food availability has often proven to be a key factor explaining their occurrence and distribution. The feeding biology of coral species has been the target of an increasing number of studies, however most of them focus on Scleractinia and Octocorallia, while information for Antipatharia is very scarce. The present study focused on Antipathella wollastoni, a common habitat-forming antipatharian in the Azores Archipelago, forming dense black coral forests between 20 and 150 meters. The objective of the study was to investigate the food preferences of the target species upon availability of different isotopically enriched food substrates and determine its ability to capture zooplankton prey under different flow speeds. The species was able to utilize different food sources including live phytoplankton, live zooplankton and Dissolved Organic Matter (DOM), indicating the ability to exploit seasonally available food sources. However ingestion of zooplankton enhanced Carbon (C) and Nitrogen (N) incorporation in coral tissue and metabolic activity, highlighting the importance of zooplankton prey for vital physiological processes such as growth and reproduction. The species displayed a high capacity to capture zooplankton prey over different flow rates, however capture rates were higher under 4 cm s-1, highlighting the ability of A. wollastoni to exploit high quantities of shortly available prey.