Diversity and connectivity of microeukaryote communities across multiple habitats from intertidal zone to deep-sea floor in the Western Pacific Ocean.

Habitat differentiation is the essential force for shaping animal and plant biogeography. Distribution patterns of microeukaryotes, which are an assemblage of highly diverse and phylogenetically distant groups, across multiple marine habitats remain largely unknown. We hypothesize that microeukaryote communities vary across different types of marine habitats at the regional scale similar as macroorganisms, and they are shaped by multiple factors. Herein, we evaluated the microeukaryotic diversity and connectivity in sediments from intertidal flat through continental shelf to deep-sea floor, including habitats of deep-sea plain, seamount, and hydrothermal vent, using high-throughput DNA sequencing. Microeukaryote communities were clustered into their own sub-groups according to the types of the habitats, where the communities of abundant taxa tended to gather with nearby habitats, while the rare taxa were mainly shaped by the types of the habitats. The SourceTracker analysis showed that the most probable sources for each community composition, particularly for those from seamounts and hydrothermal vent, were identified unknown. The continental shelf and deep-sea plain showed a relatively larger fraction of sources from each other, indicating a stronger source-sink dynamic than that among other habitats. The habitat differentiation contributed more to community variations than the spatial variables and water depth did. Co-occurrence network analysis indicated more complex bio-interactions in the neritic zone, where Cercozoa might play fundamental roles in the stability of the community than those in the deep sea, where ciliates were more connected with other taxa. Altogether, our findings highlight that the microeukaryotic communities are clearly shaped by the habitat differentiation, and this study also identifies the most probable source of dispersal for each community of different habitats. • The microeukaryotic communities were clearly shaped by the habitat differentiation. • The most probable source of dispersal for each community of different habitats was identified. • The continental shelf and deep-sea plain showed a relatively stronger source-sink dynamic. • More complex bio-interactions were observed in the neritic zone than those in the deep sea. [ABSTRACT FROM AUTHOR]