Metabarcoding reveals the differential sensitivity of planktonic microbiome to environmental filtering and biointeraction in Sansha Yongle blue hole

Abstract

The Sansha Yongle blue hole (SYBH) is the world’s deepest blue hole known so far and its unique hydrochemical characteristics make it a valuable site for studying biodiversity and ecological processes. Here, we used metabarcoding approach to investigate the diversity, assembly mechanism and co-occurrence pattern of planktonic microbiome in SYBH. Our results revealed the distinct separation of communities from upper oxic, middle oxic and suboxic-anoxic layer and significant day-night difference was detected in the upper-layer community of microeukaryotes, indicating potential diel migration. Stochastic processes played a significant role in the community assembly of microeukaryotes, while deterministic processes dominated in prokaryotes, confirming the stronger environmental filtering on prokaryotes as also suggested by the correlation with environmental variables. Microeukaryotes were less sensitive to environments but significantly affected by cross-domain biointeraction. When comparing the subcommunities of different abundance, we found that abundant taxa were widespread while rare taxa were habitat-specific. In co-occurrence network, over 87% of the interactions and 19 out of 20 keystone OTUs (Operational Taxonomic Units) were affiliated to moderate or rare taxa, suggesting the importance of non-abundant taxa in maintaining community stability. The predominant positive edges in the network pointed to that interspecies cooperation may be one of the ecological strategies in SYBH. Overall, we highlight the divergent assembly pattern and different driving forces in shaping plankton microbiome in SYBH, which may advance current understanding on diversity and dynamics of marine life in blue hole ecosystems.

DNA metabarcoding reveals ecological patterns and driving mechanisms of archaeal, bacterial, and eukaryotic communities in sediments of the Sansha Yongle Blue Hole

“…The NCM proposed by Sloan et al 33 is particularly useful in quantifying the importance of neutral processes and has been employed in bacterial community 34 – 36 , eukaryotic community 37 and microeukaryotic community 38 , 39 . Although stochastic processes seem to influence planktonic microeukaryotes and deterministic processes dominate in prokaryotic plankton in the SYBH 10 , our data from SYBH sediments indicate that stochastic processes appear to shape the sediment communities. Our results show that stochastic processes contributed to ~ 55% of the variations in archaeal, bacterial, and eukaryotic communities in SYBH sediments (Fig.…”

“…Members of Thaumarchaeota, Arthropoda and Annelida also showed a high proportion of intra-phylum interactions. Chen et al 10 suggested that abiotic factors played a minor role in shaping microeukaryotic plankton community in SYBH, and interspecies cooperation might be one of the ecological strategies. Here, co-occurrence networks suggest that biotic interactions (e.g., mutualism, commensalism, synergism) may play an important role in the distribution of these dominant taxa of prokaryotic and eukaryotic communities in SYBH sediments.…”

“…Numerous studies on water column microeukaryotic 9 , 10 and prokaryotic plankton 5 , 11 – 13 including bacteria and archaea have expanded our knowledge of the composition, structure, and potential function of the biological communities in the SYBH. The study by Liu et al 9 revealed obvious differences in the eukaryotic composition of the water column between the SYBH and the outer reef slope and demonstrated significant effects of turbidity and nitrite concentration on the eukaryotic community structure.…”

“…The study by Liu et al 9 revealed obvious differences in the eukaryotic composition of the water column between the SYBH and the outer reef slope and demonstrated significant effects of turbidity and nitrite concentration on the eukaryotic community structure. Another metabarcoding study suggested that planktonic microeukaryotes in the SYBH were less sensitive to environments but significantly affected by cross-domain biointeraction 10 . Nevertheless, limited information is available concerning the diversity, community structure and spatial distribution of eukaryotic communities in SYBH sediments, and what shapes the eukaryotic assemblages in the sediments remains unclear.…”