Feeding ecology of deep-sea seastars (Echinodermata : Asteroidea): a pigment biomarker approach

Resource partitioning and utilisation of phytodetritus by the abyssal mud-ingesting seastars Styracaster chuni and Hyphalaster inermis were investigated using pigment biomarker analysis. The chlorophyll and carotenoid pigment composition of the stomach content was examined using high-pressure liquid chromatography. No significant differences were observed between the composition of pigments in the 2 species. Both asteroid species utilise the same phytodetrital resource with no apparent partitioning of that resource. Analysis of specific biomarker pigments together with evidence from previous studies suggest that both species ingest small chlorophytes, cryptomonads, cyanobacteria, coccoliths and diatoms as part of the phytodetrital component of their diet. Phytodetrital material itself is not thought to be an important food source for H. inermis or S. chuni.