Patterns of Relative and Quantitative Abundances of Marine Bacteria in Surface Waters of the Subtropical Northwest Pacific Ocean Estimated With High-Throughput Quantification Sequencing

Abstract

Bacteria play a pivotal role in shaping ecosystems and contributing to elemental cycling and energy flow in the oceans. However, few studies have focused on bacteria at a trans-basin scale, and studies across the subtropical Northwest Pacific Ocean (NWPO), one of the largest biomes on Earth, have been especially lacking. Although the recently developed high-throughput quantitative sequencing methodology can simultaneously provide information on relative abundance, quantitative abundance, and taxonomic affiliations, it has not been thoroughly evaluated. We collected surface seawater samples for high-throughput, quantitative sequencing of 16S rRNA genes on a transect across the subtropical NWPO to elucidate the distribution of bacterial taxa, patterns of their community structure, and the factors that are potentially important regulators of that structure. We used the quantitative and relative abundances of bacterial taxa to test hypotheses related to their ecology. Total 16S rRNA gene copies ranged from 1.86 × 108 to 1.14 × 109 copies L−1. Bacterial communities were distributed in distinct geographical patterns with spatially adjacent stations clustered together. Spatial considerations may be more important determinants of bacterial community structures than measured environmental variables. The quantitative and relative abundances of bacterial communities exhibited similar distribution patterns and potentially important determinants at the whole-community level, but inner-community connections and correlations with variables differed at subgroup levels. This study advanced understanding of the community structure and distribution patterns of marine bacteria as well as some potentially important determinants thereof in a subtropical oligotrophic ocean system. Results highlighted the importance of considering both the quantitative and relative abundances of members of marine bacterial communities.

Contrasting Community Assembly Mechanisms Underlie Similar Biogeographic Patterns of Surface Microbiota in the Tropical North Pacific Ocean

“…Li et al ( 25 ) have reported that all measured variables were uncorrelated with species richness, Chao 1 indices, and Shannon indices of bacteria in the Northwestern Pacific Ocean. In the subtropical Northwest Pacific Ocean, only the PD index of bacteria has been reported to be positively correlated with concentrations of nitrite + nitrate ( 17 ). Raes et al ( 24 ) have shown that correlations between biogeochemical parameters and the species richness of bacteria and microeukaryotes differ between oceanic provinces.…”

“…4 ). Significant distance-decay patterns of bacteria and/or microeukaryotes have been found in rivers ( 12 , 13 ), lakes ( 9 , 14 ), intertidal zones ( 15 ), coastal seas ( 8 , 16 ), and open oceans ( 16 , 17 ). The underling mechanisms responsible for distance-decay patterns have been shown to differ between domains and between ecosystems ( 8 , 13 , 15 ).…”

“…Studies of marine microbial biogeography have benefited greatly from the rapid progress that has been made in genomic sequencing and theoretical microbial ecology ( 11 ). Among the various spatial distribution patterns (e.g., latitudinal diversity patterns and taxa-area relationships), distance-decay patterns have frequently been reported based on studies of communities of bacteria and microeukaryotes in a variety of aquatic habitats, including rivers ( 12 , 13 ), lakes ( 9 , 14 ), intertidal zones ( 15 ), coastal ocean ( 8 , 16 ), and open ocean ( 16 , 17 ). However, there have been few studies of microbial biogeographic patterns in oligotrophic marine waters, especially at the trans-basin scale ( 17 ).…”

Microbial Growth and Organic Matter Cycling in the Pacific Ocean Along a Latitudinal Transect Between Subarctic and Subantarctic Waters

“…The highest proportions were detected in temperate and subpolar regions and lower proportions in (sub)tropical regions. Recent reports from the SPSG, NPSG and NPTG showed that SAR116, Aegaean-169, Rickettsiales and Prochlorococcus, groups not targeted by our probes, constitute prominent proportions of the prokaryotic epipelagic communities (Reintjes et al, 2019b;Kong et al, 2021), thus presumably constituting a considerable portion of the unidentified cells. Various studies have shown that the groups we detected dominate the uptake of amino acids and glucose (Mary et al, 2006;Elifantz et al, 2007;Malmstrom et al, 2007;Alonso-Sáez et al, 2012;Bakenhus et al, 2018) and actively dividing cells (Tada et al, 2013;Bakenhus et al, 2017).…”

Environmental DNA sequencing reveals the regional difference in diversity and community assembly mechanisms of eukaryotic plankton in coastal waters

“…In terms of this mechanistic predictive framework, the relative importance of the assembly processes has been illustrated in lentic waters (Yan et al, 2017;Danczak et al, 2018), and marine ecosystems (Logares et al, 2018) by using a phylogenetic null model (Stegen et al, 2013), which enables the quantification of the influences of various ecological processes involved in the assembly of microbes. In addition, it is a fundamental element of spatial distribution patterns to clarify the biotic communities' formation and maintenance mechanism, in which distance-decay patterns of microbial communities have been stated oftentimes in freshwater lakes and rivers (Logares et al, 2018;Isabwe et al, 2019;Liu et al, 2020), ocean (Wu et al, 2018(Wu et al, , 2020Kong et al, 2020), and intertidal zones (Kong et al, 2019). However, the assembly processes of community establishment and maintenance for generating regional distribution patterns such as distance-decay, are remained to clarify in eukaryotic plankton ecology.…”