The diversity patterns of rare to abundant microbial eukaryotes across a broad range of salinities in a solar saltern. Eui-Seong solar saltern

Solar saltern is a great artificial system to examine species succession and diversity along the salinity gradient. Here the eukaryotic community was investigated in multiple ponds (30 to 380 psu) in a Korean solar saltern using Illumina sequencing with two primer sets targeting the V4 and V9 regions of 18S rDNA. A total of 926 V4 operational taxonomic units (OTUs) and 1,999 V9 OTUs were obtained. Notably, the diversity structuring of major biota (Alveolata, Stramenopila, Archaeplastida, and Opisthokonta) usually comprised >90% of total cumulative read counts, constantly sustaining their function in hypersaline ecosystems, and their fitness may be enhanced at high salinities. However, the low-abundant groups never become the dominant groups in this extreme habitat. Hence, the low-abundant groups may display a stringent distribution pattern over time in hypersaline eukaryotic communities, and this unique system may strictly select either major or minor groups. Furthermore, the taxonomic novelty with <90% sequencing identity is substantially emerging in minor groups, and vast unknown groups can contribute to the eukaryotic community. Therefore, the major and minor eukaryotic groups are considered conservative entities in hypersaline environments, and the structuring of their eukaryotic community displays greater complexity than previously realized.