Water level changes affect carbon turnover and microbial community composition in lake sediments

• Published in: FEMS microbiology ecology Vol. 92; no. 5; pp. fiw035 - 14
• Main Authors: Weise, Lukas, Ulrich, Andreas, Moreano, Matilde, Gessler, Arthur, E. Kayler, Zachary, Steger, Kristin, Zeller, Bernd, Rudolph, Kristin, Knezevic-Jaric, Jelena, Premke, Katrin
• Format: Journal Article
• Language: English
• Published: England Oxford University Press 01.05.2016; Wiley-Blackwell
• Subjects: Actinobacteria - classification; Actinobacteria - metabolism; Archaea - classification; Archaea - metabolism; Bacteria - classification; Bacteria - metabolism; bacterial biomass; bacterial communities; Biomass; Carbon; Carbon - metabolism; Carbon Cycle; carbon dioxide; Central European region; Climate Change; community structure; Desiccation; DNA; drought; drying; Environmental aspects; Europe; Fatty Acids - metabolism; Geologic Sediments - microbiology; greenhouse gas emissions; isotope labeling; Lake sediments; lakes; Lakes - microbiology; Life Sciences; littoral zone; Microbial colonies; Oxygen - metabolism; particulate organic carbon; phospholipid fatty acids; Polymorphism, Restriction Fragment Length; quantitative polymerase chain reaction; restriction fragment length polymorphism; ribosomal RNA; RNA, Ribosomal, 16S - genetics; sediments; stable isotopes; Germany; Central European region; Europe; water level changes; carbon dioxide emission; phospholipid fatty acids; stable isotope; keeling plot
• DOI: 10.1093/femsec/fiw035
• ISSN: 1574-6941; 0168-6496

Due to climate change, many lakes in Europe will be subject to higher variability of hydrological characteristics in their littoral zones. These different hydrological regimes might affect the use of allochthonous and autochthonous carbon sources. We used sandy sediment microcosms to examine the effects of different hydrological regimes (wet, desiccating, and wet-desiccation cycles) on carbon turnover. 13C-labelled particulate organic carbon was used to trace and estimate carbon uptake into bacterial biomass (via phospholipid fatty acids) and respiration. Microbial community changes were monitored by combining DNA- and RNA-based real-time PCR quantification and terminal restriction fragment length polymorphism (T-RFLP) analysis of 16S rRNA. The shifting hydrological regimes in the sediment primarily caused two linked microbial effects: changes in the use of available organic carbon and community composition changes. Drying sediments yielded the highest CO2 emission rates, whereas hydrological shifts increased the uptake of allochthonous organic carbon for respiration. T-RFLP patterns demonstrated that only the most extreme hydrological changes induced a significant shift in the active and total bacterial communities. As current scenarios of climate change predict an increase of drought events, frequent variations of the hydrological regimes of many lake littoral zones in central Europe are anticipated. Based on the results of our study, this phenomenon may increase the intensity and amplitude in rates of allochthonous organic carbon uptake and CO2 emissions. Climate changes can induce higher intensities of drying and rewetting of lake littoral zones, which in turn might result in higher allochthonous organic carbon uptake and decreased carbon storage. Graphical Abstract Figure. Climate changes can induce higher intensities of drying and rewetting of lake littoral zones, which in turn might result in higher allochthonous organic carbon uptake and decreased carbon storage.