Microeukaryotic communities of golf-ball sponges inside and outside of marine lakes

Abstract

The microbiome of sponges has been the focus of numerous studies, but relatively little is known about microeukaryotic communities inhabiting these organisms. Here, we present a study of the microeukaryotic communities of two biotopes, namely, golf-ball sponges (genera Cinachyrella and Paratetilla) and surrounding water, sampled in two marine lakes (Kakaban and Haji Buang) and one open water habitat in Borneo. Our results showed that biotopes differed in operational taxonomic unit (OTU) richness and evenness, with water samples housing more diverse microeukaryotic communities. Sponges and water, furthermore, housed compositionally distinct microeukaryotic communities. In addition to biotope (sponges versus water), habitat (different marine lakes) also proved to be a significant determinant of variation in composition. Microeukaryotic communities of sponges were dominated by members assigned to Alveolata, namely dinoflagellates, while Stramenopiles and Hacrobia were more abundant in water samples. The differences observed in sponge samples associated with habitat were mainly due to Archaeplastida members, which were more abundant in sponge samples from lake Haji Buang. Our results highlight that microeukaryotic communities appear to be largely structured by habitat, in contrast to prokaryotic communities, which seem to be mainly structured by host sponge species identity.