Transcriptomic evidences for microbial carbon and nitrogen cycles in the deoxygenated seawaters of Bohai Sea

• DOI: 10.1016/j.envint.2021.106889
• Publication Date: 2021-10-05T18:25:24Z
• Authors: Yu Han; Mu Zhang; Xiaofeng Chen; Weidong Zhai; Ehui Tan; Kai Tang
• Keywords: Thaumarchaeota; Carbon fixation; Nitrogen Cycle; Anoxygenic photosynthesis; Autotroph

Eutrophication-induced water deoxygenation occurs continually in coastal oceans, and alters community structure, metabolic processes, the energy shunt, resulting a major threat to ecological environment. Seasonal events have occurred Bohai Sea (China), however, how these affect functional activity of microorganisms remains unclear. Here, through use absolute quantification 16S rRNA genes amplicon sequencing metatranscriptomics approaches, we investigated structure microbial patterns transcriptional deoxygenated seawaters. The dominant phyla were Proteobacteria (average value, 1.4 × 106 copies ml-1), Cyanobacteria (3.7 105 Bacteroidetes (2.7 ammonia-oxidizing archaea Thaumarchaeota (1.9 ml-1). Among various environmental factors, dissolved oxygen, pH temperature displayed most significant correlation with composition activity. Metatranscriptomic data showed high waters, increase expression core representing ammonia oxidation, transport, carbon fixation (3-hydroxypropionic acid/4-hydroxybutyric acid cycle) pathways. transcripts involved photosynthesis (Calvin-Benson-Bassham significantly decreased low oxygen waters. Meanwhile, for ribulose bisphosphate carboxylase-encoding gene shifted from being assigned photoautotrophic chemoautotrophic organisms surface bottom respectively. Moreover, transcription profile indicated that heterotrophs play critical role transforming low-molecular-weight organic nitrogen. Elevated abundances related antioxidant corresponded an enhanced aerobic metabolism seawater. In general, our evidences population Thaumarchaeota, especially ecotype oxidizers, aquatic environments, contribution chemolithoautotrophic flow.