Redox potential and microbial functional gene diversity in wetland sediments under simulated warming conditions: implications for phosphorus mobilization

• Published in: Hydrobiologia Vol. 743; no. 1; pp. 221 - 235
• Main Authors: Zhang, Zhijian, Wang, Hang, Zhou, Jizhong, Li, Hongyi, He, Zhili, Van Nostrand, Joy D, Wang, Zhaode, Xu, Xinhua
• Format: Journal Article
• Language: English
• Published: Cham Springer-Verlag 01.01.2015; Springer International Publishing; Springer; Springer Nature B.V
• Subjects: acetyl-CoA carboxylase; Ambient temperature; Aquatic ecosystems; biochemical pathways; Biogeochemical cycles; Biogeochemistry; Biomedical and Life Sciences; Biotin; carbon; Carbon fixation; Carbon monoxide; Climate change; cytochrome c; Denitrification; DNA microarrays; Ecology; Eutrophication; freshwater; Freshwater & Marine Ecology; Genes; Genetic diversity; Genetic research; Global temperature changes; Global warming; Hypoxia; Life Sciences; microarray technology; Microbial activity; microbial communities; nitrates; Nitrous oxide; Oxidation-reduction potential; Phosphorus; Primary Research Paper; Redox potential; ribulose-bisphosphate carboxylase; risk; Sediment samplers; sediments; water potential; Wetlands; Zoology; Warming; Biogeochemical cycling; Functional gene; Freshwater wetland
• ISSN: 0018-8158; 1573-5117
• DOI: 10.1007/s10750-014-2039-6

Microbial-driven biogeochemical cycles in wetlands impacted by global warming pose a potential downstream eutrophication risk. However, the consequences of ongoing warming on the functional and metabolic potential of sediment microbial communities are largely unknown. We incubated sediment samples under both ambient temperature conditions (control) and simulated warming conditions of 5°C above ambient temperature (warmed) using a novel field microcosm system. In warmed samples, we observed in situ a decreased thickness of the oxidized sediment layer and associated lower sediment redox potential. GeoChip 4.0, a comprehensive functional gene microarray, demonstrated that many functional genes that are involved in oxidation–reduction reactions and in phosphorus (P) degradation were preferentially enriched under warming conditions. The enriched genes included those genes encoding carbon monoxide dehydrogenase, acetyl-CoA carboxylase biotin carboxylase (ppc), and ribulose-1,5-bisphosphate carboxylase (Rubisco) for carbon fixation; nitrate reductases (narG) and nitrous oxide reductases (nosZ) for denitrification; cytochrome c for metal reduction; and exopolyphosphatase (ppx) for polyphosphate degradation. The redox potential was one of the most significant parameters linked to microbial functional gene structure. These results demonstrate that the enhanced hypoxia and anaerobic metabolic pathways accelerated sediment P mobilization in freshwater wetland subject to warming, raising the potential of water eutrophication.