@article{FrindteAllgaierGrossartetal.2015,
  author    = {Frindte, Katharina and Allgaier, Martin and Grossart, Hans-Peter and Eckert, Werner},
  title     = {Microbial response to experimentally controlled redox transitions at the sediment water interface},
  series = {PLoS one},
  volume    = {10},
  journal   = {PLoS one},
  number    = {11},
  publisher = {PLoS},
  address   = {San Fransisco},
  issn      = {1932-6203},
  doi       = {10.1371/journal.pone.0143428},
  pages     = {17},
  year      = {2015},
  abstract  = {The sediment-water interface of freshwater lakes is characterized by sharp chemical gradients, shaped by the interplay between physical, chemical and microbial processes. As dissolved oxygen is depleted in the uppermost sediment, the availability of alternative electron acceptors, e.g. nitrate and sulfate, becomes the limiting factor. We performed a time series experiment in a mesocosm to simulate the transition from aerobic to anaerobic conditions at the sediment-water interface. Our goal was to identify changes in the microbial activity due to redox transitions induced by successive depletion of available electron acceptors. Monitoring critical hydrochemical parameters in the overlying water in conjunction with a new sampling strategy for sediment bacteria enabled us to correlate redox changes in the water to shifts in the active microbial community and the expression of functional genes representing specific redox-dependent microbial processes. Our results show that during several transitions from oxic-heterotrophic condition to sulfate-reducing condition, nitrate-availability and the on-set of sulfate reduction strongly affected the corresponding functional gene expression. There was evidence of anaerobic methane oxidation with NOx. DGGE analysis revealed redox-related changes in microbial activity and expression of functional genes involved in sulfate and nitrite reduction, whereas methanogenesis and methanotrophy showed only minor changes during redox transitions. The combination of high-frequency chemical measurements and molecular methods provide new insights into the temporal dynamics of the interplay between microbial activity and specific redox transitions at the sediment-water interface.},
  language  = {en}
}
@article{WurzbacherWarthmannBourneetal.2016,
  author    = {Wurzbacher, Christian and Warthmann, Norman and Bourne, Elizabeth Charlotte and Attermeyer, Katrin and Allgaier, Martin and Powell, Jeff R. and Detering, Harald and Mbedi, Susan and Großart, Hans-Peter and Monaghan, Michael T.},
  title     = {High habitat-specificity in fungal communities in oligo-mesotrophic, temperate Lake Stechlin (North-East Germany)},
  series = {MycoKeys},
  volume    = {41},
  journal   = {MycoKeys},
  publisher = {Pensoft Publ.},
  address   = {Sofia},
  issn      = {1314-4057},
  doi       = {10.3897/mycokeys.16.9646},
  pages     = {17 -- 44},
  year      = {2016},
  abstract  = {Freshwater fungi are a poorly studied ecological group that includes a high taxonomic diversity. Most studies on aquatic fungal diversity have focused on single habitats, thus the linkage between habitat heterogeneity and fungal diversity remains largely unexplored. We took 216 samples from 54 locations representing eight different habitats in the meso-oligotrophic, temperate Lake Stechlin in North-East Germany. These included the pelagic and littoral water column, sediments, and biotic substrates. We performed high throughput sequencing using the Roche 454 platform, employing a universal eukaryotic marker region within the large ribosomal subunit (LSU) to compare fungal diversity, community structure, and species turnover among habitats. Our analysis recovered 1027 fungal OTUs (97\% sequence similarity). Richness estimates were highest in the sediment, biofilms, and benthic samples (189-231 OTUs), intermediate in water samples (42-85 OTUs), and lowest in plankton samples (8 OTUs). NMDS grouped the eight studied habitats into six clusters, indicating that community composition was strongly influenced by turnover among habitats. Fungal communities exhibited changes at the phylum and order levels along three different substrate categories from littoral to pelagic habitats. The large majority of OTUs (> 75\%) could not be classified below the order level due to the lack of aquatic fungal entries in public sequence databases. Our study provides a first estimate of lake-wide fungal diversity and highlights the important contribution of habitat heterogeneity to overall diversity and community composition. Habitat diversity should be considered in any sampling strategy aiming to assess the fungal diversity of a water body.},
  language  = {en}
}
@misc{FrindteAllgaierGrossartetal.2015,
  author    = {Frindte, Katharina and Allgaier, Martin and Grossart, Hans-Peter and Eckert, Werner},
  title     = {Microbial response to experimentally controlled redox transitions at the sediment water interface},
  series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
  journal   = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
  number    = {509},
  issn      = {1866-8372},
  doi       = {10.25932/publishup-40846},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-408464},
  pages     = {17},
  year      = {2015},
  abstract  = {The sediment-water interface of freshwater lakes is characterized by sharp chemical gradients, shaped by the interplay between physical, chemical and microbial processes. As dissolved oxygen is depleted in the uppermost sediment, the availability of alternative electron acceptors, e.g. nitrate and sulfate, becomes the limiting factor. We performed a time series experiment in a mesocosm to simulate the transition from aerobic to anaerobic conditions at the sediment-water interface. Our goal was to identify changes in the microbial activity due to redox transitions induced by successive depletion of available electron acceptors. Monitoring critical hydrochemical parameters in the overlying water in conjunction with a new sampling strategy for sediment bacteria enabled us to correlate redox changes in the water to shifts in the active microbial community and the expression of functional genes representing specific redox-dependent microbial processes. Our results show that during several transitions from oxic-heterotrophic condition to sulfate-reducing condition, nitrate-availability and the on-set of sulfate reduction strongly affected the corresponding functional gene expression. There was evidence of anaerobic methane oxidation with NOx. DGGE analysis revealed redox-related changes in microbial activity and expression of functional genes involved in sulfate and nitrite reduction, whereas methanogenesis and methanotrophy showed only minor changes during redox transitions. The combination of high-frequency chemical measurements and molecular methods provide new insights into the temporal dynamics of the interplay between microbial activity and specific redox transitions at the sediment-water interface.},
  language  = {en}
}
@article{RoeselAllgaierGrossart2012,
  author    = {Roesel, Stefan and Allgaier, Martin and Grossart, Hans-Peter},
  title     = {Long-Term characterization of free-living and particle-associated bacterial communities in lake Tiefwaren reveals distinct seasonal patterns},
  series = {Microbial ecology},
  volume    = {64},
  journal   = {Microbial ecology},
  number    = {3},
  publisher = {Springer},
  address   = {New York},
  issn      = {0095-3628},
  doi       = {10.1007/s00248-012-0049-3},
  pages     = {571 -- 583},
  year      = {2012},
  abstract  = {Seasonal changes in environmental conditions have a strong impact on microbial community structure and dynamics in aquatic habitats. To better elucidate the response of bacterial communities to environmental changes, we have measured a large variety of limnetic variables and investigated bacterial community composition (BCC) and dynamics over seven consecutive years between 2003 and 2009 in mesotrophic Lake Tiefwaren (NE Germany). We separated between free-living (FL, > 0.2, < 5.0 mu m) and particle-associated (PA, > 5.0 mu m) bacteria to account for different bacterial lifestyles and to obtain a higher resolution of the microbial diversity. Changes in BCC were studied by DGGE based on PCR-amplified 16S rRNA gene fragments. Sequencing of DGGE bands revealed that ca. 70 \% of all FL bacteria belonged to the Actinobacteria, whereas PA bacteria were dominated by Cyanobacteria (43 \%). FL communities were generally less diverse and rather stable over time compared to their PA counterpart. Annual changes in reoccurring seasonal patterns of dominant freshwater bacteria were supported by statistical analyses, which revealed several significant correlations between DGGE profiles and various environmental variables, e.g. temperature and nutrients. Overall, FL bacteria were generally less affected by environmental changes than members of the PA fraction. Close association of PA bacteria with phytoplankton and zooplankton suggests a tight coupling of PA bacteria to organisms of higher trophic levels. Our results indicate substantial differences in bacterial lifestyle of pelagic freshwater bacteria, which are reflected by contrasting seasonal dynamics and relationships to a number of environmental variables.},
  language  = {en}
}
@article{AttermeyerTittelAllgaieretal.2015,
  author    = {Attermeyer, Katrin and Tittel, Joerg and Allgaier, Martin and Frindte, Katharina and Wurzbacher, Christian and Hilt, Sabine and Kamjunke, Norbert and Grossart, Hans-Peter},
  title     = {Effects of Light and Autochthonous Carbon Additions on Microbial Turnover of Allochthonous Organic Carbon and Community Composition},
  series = {Microbial ecology},
  volume    = {69},
  journal   = {Microbial ecology},
  number    = {2},
  publisher = {Springer},
  address   = {New York},
  issn      = {0095-3628},
  doi       = {10.1007/s00248-014-0549-4},
  pages     = {361 -- 371},
  year      = {2015},
  abstract  = {The fate of allochthonous dissolved organic carbon (DOC) in aquatic systems is primarily controlled by the turnover of heterotrophic bacteria. However, the roles that abiotic and biotic factors such as light and DOC release by aquatic primary producers play in the microbial decomposition of allochthonous DOC is not well understood. We therefore tested if light and autochthonous DOC additions would increase allochthonous DOC decomposition rates and change bacterial growth efficiencies and community composition (BCC). We established continuous growth cultures with different inocula of natural bacterial communities and alder leaf leachates (DOCleaf) with and without light exposure before amendment. Furthermore, we incubated DOCleaf together with autochthonous DOC from lysed phytoplankton cultures (DOCphyto). Our results revealed that pretreatments of DOCleaf with light resulted in a doubling of bacterial growth efficiency (BGE), whereas additions of DOCphyto or combined additions of DOCphyto and light had no effect on BGE. The change in BGE was not accompanied by shifts in the phylogenetic structure of the BCC, but BCC was influenced by the DOC source. Our results highlight that a doubling of BGE is not necessarily accompanied by a shift in BCC and that BCC is more strongly affected by resource properties.},
  language  = {en}
}