Diatoms as a food source for Sorites dominicensis

Sorites dominicensis is a common Foraminifera living on Thalassia testudinum seagrass blades in the Indian River Lagoon. This locality is unique because epiphytic diatoms, characteristic of Caribbean and temperate environments, are expected to make up the biofilm community. Diatoms compose a large part of the Foraminiferan diet. It is important to understand the cause and effect relationship of population variation between S. dominicensis and its preferred food source, since both are valuable bioindicators. We examined the selective feeding of S. dominicensis by first, identifying the diatom assemblage. Second, we utilized scanning electron microscopy (SEM) in order to identifying the remains of diatoms entrapped in pseudopodial nets and in debris piles. We found that Mastogloia and Cocconeis were the most prominent genera in the overall diatom assemblage. The food preference of S. dominicensis included Amphora, Berkeleya rutilans,Cocconeis, Licmophora dalmatica, Mastogloia, Odontella rhombus, Plagiogramma pulchellum var. pygmaeum, and Skeletonema.