Geographical variation and connectivity of micro-eukaryotes in the seamount sediments of the Western Pacific Ocean

The knowledge of microbial biogeography directly influences our understanding on the global biodiversity and the underlying processes that shape their distribution. However, little is known about the patterns and drivers of microbial eukaryotic distribution at a regional scale. We selected seamounts and trenches in the Western Pacific Ocean to investigate the diversity and distribution of microeukaryotes based on high throughput DNA sequencing, especially different metabolic groups. The microeukaryotic community showed a marked spatial pattern in this region. Environmental variables including nitrate, ammonia, total organci carbon and total nitrogen were strongly correlated with the composition and assembly of the microeukaryotic community, explaining 59.37% of variation in the microeukaryotic community. Co-occurrence network analysis revealed that species interactions within/among bacteria, archaea and microeukaryotes impacted the microeukaryotic community assembly. The microeukaryotes of the seamount sediments in the Mariana-Yap junction area has greater specificity on the vertical scale. Various micro/nano/picograzers, decomposers and parasitic taxa were found, and the highly connectivity of parasites and grazers indicates top-down control might play an important role in microeukaryotic food web. This study provides insights into the ecological patterns, assembly processes and species interactions underlying microeukaryotic dynamics in seamounts and trenches of the Western Pacific Ocean.