Marine Group II Dominates Planktonic Archaea in Water Column of the Northeastern South China Sea

Abstract

Temperature, nutrients, and salinity are among the important factors constraining the distribution and abundance of microorganisms in the ocean. Marine Group II (MGII) belonging to Euryarchaeota commonly dominates the planktonic archaeal community in shallow water and Marine Group I (MGI, now is called Thaumarchaeota) in deeper water in global oceans. Results of quantitative PCR (qPCR) and 454 sequencing in our study, however, showed the dominance of MGII in planktonic archaea throughout the water column of the northeastern South China Sea (SCS) that is characterized by strong water mixing. The abundance of ammonia-oxidizing archaea (AOA) representing the main group of Thaumarchaeota in deeper water in the northeastern SCS was significantly lower than in other oceanic regions. Phylogenetic analysis showed that the top operational taxonomic units (OTUs) of the MGII occurring predominantly below 200 m depth may be unique in the northeastern SCS based on the observation that they are distantly related to known sequences (identity ranging from 90–94%). The abundance of MGII was also significantly correlated with total bacteria in the whole column, which may indicate that MGII and bacteria may have similar physiological or biochemical properties or responses to environmental variation. This study provides valuable information about the dominance of MGII over AOA in both shallow and deep water in the northeastern SCS and highlights the need for comprehensive studies integrating physical, chemical, and microbial oceanography.

The absence of intact polar lipid-derived GDGTs in marine waters dominated by Marine Group II: Implications for lipid biosynthesis in Archaea

“…www.nature.com/scientificreports www.nature.com/scientificreports/ depth in the tropical North Atlantic Ocean. This is in line with the reported niche preference of MGI archaea for subsurface waters (approximately 50-500 m depth) 10,23,32,34,35 . The MGI archaeal abundance in summer coastal North Sea was 7 × 10 6 cells L −1 , similar to earlier studies 19,28 reporting MGI archaeal abundances of < 1 × 10 7 cells L −1 in summer coastal North Sea SPM.…”

Archaeal biogeography and interactions with microbial community across complex subtropical coastal waters

“…We found even stronger phylogenetic signal in niche differences between abundant MGII OTUs, also suggesting niche partitioning within MGII. MGII as a whole often outcompete MGI within the upper photic zone of temperate/subtropical waters (Liu et al, ; Massana et al, ), which is not the case in this study, as MGII only overwhelmed MGI in YS but at low abundances (Figure ). The patchy distribution of MGII could be reflected by its shallow relationships with measured environmental parameters except DO (Table ).…”

Localized high abundance of Marine Group II archaea in the subtropical Pearl River Estuary: implications for their niche adaptation

“…Planktonic archaea include four major groups, with Marine Group I (MGI) being currently recognized as marine Thaumarchaeota, and Marine Group II (MGII), Marine Group III (MGIII) and Marine Group IV (MGIV) (L opez-García et al, 2001) being the uncultured groups of Euryarchaeota. While MGII are more abundant in surface waters (Fuhrman and Davis, 1997;Massana et al, 2000;L opez-García et al, 2001;Mincer et al, 2007) and were also found in deep-sea water (Deschamps et al, 2014;Li et al, 2015;Liu et al, 2017), marine Thaumarchaeota are more abundant in meso-and bathypelagic waters (Karner et al, 2001;Herndl et al, 2005;Mincer et al, 2007;Teira et al, 2008;Varela et al, 2008). MGIII are generally considered to be more restricted to deeper waters (Massana et al, 2000;Galand et al, 2009) and, to a lesser extent, the photic zone (Haro-Moreno et al, 2017).…”