TY - JOUR A1 - Wurzbacher, Christian A1 - Fuchs, Andrea A1 - Attermeyer, Katrin A1 - Frindte, Katharina A1 - Grossart, Hans-Peter A1 - Hupfer, Michael A1 - Casper, Peter A1 - Monaghan, Michael T. T1 - Shifts among Eukaryota, Bacteria, and Archaea define the vertical organization of a lake sediment JF - Microbiome N2 - Background: Lake sediments harbor diverse microbial communities that cycle carbon and nutrients while being constantly colonized and potentially buried by organic matter sinking from the water column. The interaction of activity and burial remained largely unexplored in aquatic sediments. We aimed to relate taxonomic composition to sediment biogeochemical parameters, test whether community turnover with depth resulted from taxonomic replacement or from richness effects, and to provide a basic model for the vertical community structure in sediments. Methods: We analyzed four replicate sediment cores taken from 30-m depth in oligo-mesotrophic Lake Stechlin in northern Germany. Each 30-cm core spanned ca. 170 years of sediment accumulation according to Cs-137 dating and was sectioned into layers 1-4 cm thick. We examined a full suite of biogeochemical parameters and used DNA metabarcoding to examine community composition of microbial Archaea, Bacteria, and Eukaryota. Results: Community beta-diversity indicated nearly complete turnover within the uppermost 30 cm. We observed a pronounced shift from Eukaryota- and Bacteria-dominated upper layers (<5 cm) to Bacteria-dominated intermediate layers (5-14 cm) and to deep layers (>14 cm) dominated by enigmatic Archaea that typically occur in deep-sea sediments. Taxonomic replacement was the prevalent mechanism in structuring the community composition and was linked to parameters indicative of microbial activity (e.g., CO2 and CH4 concentration, bacterial protein production). Richness loss played a lesser role but was linked to conservative parameters (e.g., C, N, P) indicative of past conditions. Conclusions: By including all three domains, we were able to directly link the exponential decay of eukaryotes with the active sediment microbial community. The dominance of Archaea in deeper layers confirms earlier findings from marine systems and establishes freshwater sediments as a potential low-energy environment, similar to deep sea sediments. We propose a general model of sediment structure and function based on microbial characteristics and burial processes. An upper "replacement horizon" is dominated by rapid taxonomic turnover with depth, high microbial activity, and biotic interactions. A lower "depauperate horizon" is characterized by low taxonomic richness, more stable "low-energy" conditions, and a dominance of enigmatic Archaea. KW - Archaea KW - Eukaryota KW - Bacteria KW - Community KW - Freshwater KW - Lake KW - DNA metabarcoding KW - Beta-diversity KW - Sediment KW - Turnover Y1 - 2017 U6 - https://doi.org/10.1186/s40168-017-0255-9 SN - 2049-2618 VL - 5 PB - BioMed Central CY - London ER - TY - JOUR A1 - Teckentrup, Lisa A1 - Kramer-Schadt, Stephanie A1 - Jeltsch, Florian T1 - The risk of ignoring fear: underestimating the effects of habitat loss and fragmentation on biodiversity JF - Landscape ecology KW - Predator-prey interactions KW - Fragmentation KW - Habitat loss KW - Landscape of fear KW - Biodiversity KW - Community Y1 - 2019 U6 - https://doi.org/10.1007/s10980-019-00922-8 SN - 0921-2973 SN - 1572-9761 VL - 34 IS - 12 SP - 2851 EP - 2868 PB - Springer CY - Dordrecht ER - TY - GEN A1 - Gronau, Norbert T1 - Marktüberblick T1 - Applications and systems for knowledge management BT - Anwendungen und Systeme für das Wissensmanagement BT - a market survey N2 - Diese Marktstudie vermittelt einen Überblick über Software, die zur Unterstützung von Wissensmanagement eingesetzt werden kann und berücksichtigt dabei die Spannweite von spezialisierten Suchmaschinen bis zu umfassenden integrierten Wissensmanagementsystemen. Die untersuchte Software bietet sowohl Unterstützung bei Community-orientierten Wissensmanagementansätzen als auch bei Information Retrieval. Die Einsatzmöglichkeiten sind genauso unterschiedlich wie die heterogenen Anforderungen von Unternehmen und Organisationen, die diese an Wissensmanagement stellen. Eine direkte Vergleichbarkeit aller untersuchten Softwareprodukte ist daher nicht sinnvoll. N2 - Applications and systems for knowledge management : a market survey: This market survey gives an overview on software for the support of knowledge management. The survey overlooks the span from specialized search engines to integrated knowledge management systems with a broad range of functions. The investigated software supports community-oriented approaches as well as information retrieval. Usage possibilities are as different as the heterogenous requirements of enterprises and organizations for knowledge management. Therefore a direct comparison between the investigated tools is not useful. ----- © GITO mbH Berlin KW - Wissensmanagement KW - Portal KW - Suchmaschine KW - Diskussion KW - Marktübersicht KW - Community KW - knowledge management KW - community KW - portal KW - search engine KW - discussion KW - market survey Y1 - 2005 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-6814 ER -