The Yellow Sea features unique characteristics due to strong tides and nutrient-enriched
freshwater outflows from China and Korea. The coupling of archaeal and bacterial assemblages
associated with environmental factors at two bay areas in the Yellow Sea was investigated.
Temporal variations of the archaeal and bacterial assemblages were shown to be
greater than the spatial variations based on an analysis of the 16S rRNA gene sequences.
Distinct temporal dynamics of both planktonic archaeal and bacterial assemblages was
associated with temperature, NO2
-, and chlorophyll a ([chl-a]) concentrations in the bays of
the Yellow Sea. The [chl-a] was the prime predictor of bacterial abundance, and some taxa
were clearly correlated with [chl-a]. Bacteroidetes and Alpha-proteobacteria dominated at
high [chl-a] stations while Gamma-proteobacteria (esp. SAR86 clade) and Actinobacteria
(Candidatus Actinomarina clade) were abundant at low [chl-a] stations. The archaeal abundance
was comparable with the bacterial abundance in most of the October samples. Codominance
of Marine Group II (MGII) and Candidatus Nitrosopumilus suggests that the
assimilation of organic nitrogen by MGII could be coupled with nitrification by ammonia-oxidizing
archaea. The distinct temporal dynamics of the archaeal and bacterial assemblages
might be attributable to the strong tides and the inflow of nutrient-rich freshwater