TY - JOUR A1 - Attermeyer, Katrin A1 - Premke, Katrin A1 - Hornick, Thomas A1 - Hilt, Sabine A1 - Grossart, Hans-Peter T1 - Ecosystem-level studies of terrestrial carbon reveal contrasting bacterial metabolism in different aquatic habitats JF - Ecology : a publication of the Ecological Society of America N2 - In aquatic systems, terrestrial dissolved organic matter (t-DOM) is known to stimulate bacterial activities in the water column, but simultaneous effects of autumnal leaf input on water column and sediment microbial dynamics in littoral zones of lakes remain largely unknown. The study's objective was to determine the effects of leaf litter on bacterial metabolism in the littoral water and sediment, and subsequently, the consequences for carbon cycling and food web dynamics. Therefore, in late fall, we simultaneously measured water and sediment bacterial metabolism in the littoral zone of a temperate shallow lake after adding terrestrial particulate organic matter (t-POM), namely, maize leaves. To better evaluate bacterial production (BP) and community respiration (CR) in sediments, we incubated sediment cores with maize leaves of different quality (nonleached and leached) under controlled laboratory conditions. Additionally, to quantify the incorporated leaf carbon into microbial biomass, we determined carbon isotopic ratios of fatty acids from sediment and leaf-associated microbes from a laboratory experiment using C-13-enriched beech leaves. The concentrations of dissolved organic carbon (DOC) increased significantly in the lake after the addition of maize leaves, accompanied by a significant increase in water BP. In contrast, sediment BP declined after an initial peak, showing no positive response to t-POM addition. Sediment BP and CR were also not stimulated by t-POM in the laboratory experiment, either in short-term or in long-term incubations, except for a short increase in CR after 18 hours. However, this increase might have reflected the metabolism of leaf-associated microorganisms. We conclude that the leached t-DOM is actively incorporated into microbial biomass in the water column but that the settling leached t-POM (t-POML) does not enter the food web via sediment bacteria. Consequently, t-POML is either buried in the sediment or introduced into the aquatic food web via microorganisms (bacteria and fungi) directly associated with t-POML and via benthic macroinvertebrates by shredding of t-POML. The latter pathway represents a benthic shortcut which efficiently transfers t-POML to higher trophic levels. KW - bacterial production KW - carbon turnover KW - community respiration KW - leaf litter KW - phospholipid-derived fatty acid KW - PLFA KW - Schulzensee KW - Germany KW - sediments KW - shallow lakes KW - stable isotopes KW - terrestrial subsidies Y1 - 2013 U6 - https://doi.org/10.1890/13-0420.1 SN - 0012-9658 SN - 1939-9170 VL - 94 IS - 12 SP - 2754 EP - 2766 PB - Wiley CY - Washington ER - TY - JOUR A1 - Fabian, Jenny A1 - Zlatanovic, Sanja A1 - Mutz, Michael A1 - Grossart, Hans-Peter A1 - van Geldern, Robert A1 - Ulrich, Andreas A1 - Gleixner, Gerd A1 - Premke, Katrin T1 - Environmental control on microbial turnover of leaf carbon in streams BT - Ecological function of phototrophic-heterotrophic interactions JF - Frontiers in microbiology N2 - In aquatic ecosystems, light availability can significantly influence microbial turnover of terrestrial organic matter through associated metabolic interactions between phototrophic and heterotrophic communities. However, particularly in streams, microbial functions vary significantly with the structure of the streambed, that is the distribution and spatial arrangement of sediment grains in the streambed. It is therefore essential to elucidate how environmental factors synergistically define the microbial turnover of terrestrial organic matter in order to better understand the ecological role of photoheterotrophic interactions in stream ecosystem processes. In outdoor experimental streams, we examined how the structure of streambeds modifies the influence of light availability on microbial turnover of leaf carbon (C). Furthermore, we investigated whether the studied relationships of microbial leaf C turnover to environmental conditions are affected by flow intermittency commonly occurring in streams. We applied leaves enriched with a C-13-stable isotope tracer and combined quantitative and isotope analyses. We thereby elucidated whether treatment induced changes in C turnover were associated with altered use of leaf C within the microbial food web. Moreover, isotope analyses were combined with measurements of microbial community composition to determine whether changes in community function were associated with a change in community composition. In this study, we present evidence, that environmental factors interactively determine how phototrophs and heterotrophs contribute to leaf C turnover. Light availability promoted the utilization of leaf C within the microbial food web, which was likely associated with a promoted availability of highly bioavailable metabolites of phototrophic origin. However, our results additionally confirm that the structure of the streambed modifies light-related changes in microbial C turnover. From our observations, we conclude that the streambed structure influences the strength of photo-heterotrophic interactions by defining the spatial availability of algal metabolites in the streambed and the composition of microbial communities. Collectively, our multifactorial approach provides valuable insights into environmental controls on the functioning of stream ecosystems. KW - algae KW - bacteria KW - microbial interactions KW - C-13 stable isotopes KW - PLFA KW - terrestrial carbon KW - streambed structure KW - light Y1 - 2018 U6 - https://doi.org/10.3389/fmicb.2018.01044 SN - 1664-302X VL - 9 PB - Frontiers Research Foundation CY - Lausanne ER - TY - GEN A1 - Fabian, Jenny A1 - Zlatanović, Sanja A1 - Mutz, Michael A1 - Grossart, Hans-Peter A1 - Geldern, Robert van A1 - Ulrich, Andreas A1 - Gleixner, Gerd A1 - Premke, Katrin T1 - Environmental control on microbial turnover of leaf carbon in streams BT - ecological function of phototrophic-heterotrophic interactions T2 - Postprints der Universität Potsdam Mathematisch-Naturwissenschaftliche Reihe N2 - In aquatic ecosystems, light availability can significantly influence microbial turnover of terrestrial organic matter through associated metabolic interactions between phototrophic and heterotrophic communities. However, particularly in streams, microbial functions vary significantly with the structure of the streambed, that is the distribution and spatial arrangement of sediment grains in the streambed. It is therefore essential to elucidate how environmental factors synergistically define the microbial turnover of terrestrial organic matter in order to better understand the ecological role of photo-heterotrophic interactions in stream ecosystem processes. In outdoor experimental streams, we examined how the structure of streambeds modifies the influence of light availability on microbial turnover of leaf carbon (C). Furthermore, we investigated whether the studied relationships of microbial leaf C turnover to environmental conditions are affected by flow intermittency commonly occurring in streams. We applied leaves enriched with a 13C-stable isotope tracer and combined quantitative and isotope analyses. We thereby elucidated whether treatment induced changes in C turnover were associated with altered use of leaf C within the microbial food web. Moreover, isotope analyses were combined with measurements of microbial community composition to determine whether changes in community function were associated with a change in community composition. In this study, we present evidence, that environmental factors interactively determine how phototrophs and heterotrophs contribute to leaf C turnover. Light availability promoted the utilization of leaf C within the microbial food web, which was likely associated with a promoted availability of highly bioavailable metabolites of phototrophic origin. However, our results additionally confirm that the structure of the streambed modifies light-related changes in microbial C turnover. From our observations, we conclude that the streambed structure influences the strength of photo-heterotrophic interactions by defining the spatial availability of algal metabolites in the streambed and the composition of microbial communities. Collectively, our multifactorial approach provides valuable insights into environmental controls on the functioning of stream ecosystems. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 693 KW - algae KW - bacteria KW - microbial interactions KW - 13C stable isotopes KW - PLFA KW - terrestrial carbon KW - streambed structure KW - light Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-426336 SN - 1866-8372 IS - 693 ER - TY - JOUR A1 - Taube, Robert A1 - Ganzert, Lars A1 - Grossart, Hans-Peter A1 - Gleixner, Gerd A1 - Premke, Katrin T1 - Organic matter quality structures benthic fatty acid patterns and the abundance of fungi and bacteria in temperate lakes JF - The science of the total environment : an international journal for scientific research into the environment and its relationship with man N2 - Benthic microbial communities (BMCs) play important roles in the carbon cycle of lakes, and benthic littoral zones in particular have been previously highlighted as biogeochemical hotspots. Dissolved organic matter (DOM) presents the major carbon pool in lakes, and although the effect of DOM composition on the pelagic microbial community composition is widely accepted, little is known about its effect on BMCs, particularly aquatic fungi. Therefore, we investigated the composition of benthic littoral microbial communities in twenty highly diverse lakes in northeast Germany. DOM quality was analyzed via size exclusion chromatography (SEC), fluorescence parallel factor analyses (PRAFACs) and UV-Vis spectroscopy. We determined the BMC composition and biomass using phospholipid-derived fatty acids (PLFA) and extended the interpretation to the analysis of fungi by applying a Bayesian mixed model. We present evidence that the quality of DOM structures the BMCs, which are dominated by heterotrophic bacteria and show low fungal biomass. The fungal biomass increases when the DOM pool is processed by microorganisms of allochthonous origin, whereas the opposite is true for bacteria. KW - PLFA KW - PARAFAC KW - Size exclusion chromatography (SEC) KW - Aquatic fungi KW - Stable isotopes KW - FASTAR Y1 - 2017 U6 - https://doi.org/10.1016/j.scitotenv.2017.07.256 SN - 0048-9697 SN - 1879-1026 VL - 610 SP - 469 EP - 481 PB - Elsevier CY - Amsterdam ER -