@phdthesis{Wen2020,
  author    = {Wen, Xi},
  title     = {Distribution patterns and environmental drivers of methane-cycling microorganisms in natural environments and restored wetlands},
  doi       = {10.25932/publishup-47177},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-471770},
  school      = {Universit{\"a}t Potsdam},
  pages     = {VIII, iii, 152},
  year      = {2020},
  abstract  = {Methane is an important greenhouse gas contributing to global climate change. Natural environments and restored wetlands contribute a large proportion to the global methane budget. Methanogenic archaea (methanogens) and methane oxidizing bacteria (methanotrophs), the biogenic producers and consumers of methane, play key roles in the methane cycle in those environments. A large number of studies revealed the distribution, diversity and composition of these microorganisms in individual habitats. However, uncertainties exist in predicting the response and feedback of methane-cycling microorganisms to future climate changes and related environmental changes due to the limited spatial scales considered so far, and due to a poor recognition of the biogeography of these important microorganisms combining global and local scales. With the aim of improving our understanding about whether and how methane-cycling microbial communities will be affected by a series of dynamic environmental factors in response to climate change, this PhD thesis investigates the biogeographic patterns of methane-cycling communities, and the driving factors which define these patterns at different spatial scales. At the global scale, a meta-analysis was performed by implementing 94 globally distributed public datasets together with environmental data from various natural environments including soils, lake sediments, estuaries, marine sediments, hydrothermal sediments and mud volcanos. In combination with a global biogeographic map of methanogenic archaea from multiple natural environments, this thesis revealed that biogeographic patterns of methanogens exist. The terrestrial habitats showed higher alpha diversities than marine environments. Methanoculleus and Methanosaeta (Methanothrix) are the most frequently detected taxa in marine habitats, while Methanoregula prevails in terrestrial habitats. Estuary ecosystems, the transition zones between marine and terrestrial/limnic ecosystems, have the highest methanogenic richness but comparably low methane emission rates. At the local scale, this study compared two rewetted fens with known high methane emissions in northeastern Germany, a coastal brackish fen (H{\"u}telmoor) and a freshwater riparian fen (Polder Zarnekow). Consistent with different geochemical conditions and land-use history, the two rewetted fens exhibit dissimilar methanogenic and, especially, methanotrophic community compositions. The methanotrophic community was generally under-represented among the prokaryotic communities and both fens show similarly low ratios of methanotrophic to methanogenic abundances. Since few studies have characterized methane-cycling microorganisms in rewetted fens, this study provides first evidence that the rapid and well re-established methanogenic community in combination with the low and incomplete re-establishment of the methanotrophic community after rewetting contributes to elevated sustained methane fluxes following rewetting. Finally, this thesis demonstrates that dispersal limitation only slightly regulates the biogeographic distribution patterns of methanogenic microorganisms in natural environments and restored wetlands. Instead, their existence, adaption and establishment are more associated with the selective pressures under different environmental conditions. Salinity, pH and temperature are identified as the most important factors in shaping microbial community structure at different spatial scales (global versus terrestrial environments). Predicted changes in climate, such as increasing temperature, changes in precipitation patterns and increasing frequency of flooding events, are likely to induce a series of environmental alterations, which will either directly or indirectly affect the driving environmental forces of methanogenic communities, leading to changes in their community composition and thus potentially also in methane emission patterns in the future.},
  language  = {en}
}
@article{Paessler2021,
  author    = {P{\"a}ßler, Ulrich},
  title     = {Christian Gottfried Ehrenberg und die Biogeographie: Die russisch-sibirische Reise mit Alexander von Humboldt (1829)},
  series = {HiN : Alexander von Humboldt im Netz = Christian Gottfried Ehrenberg},
  volume    = {XXII},
  journal   = {HiN : Alexander von Humboldt im Netz = Christian Gottfried Ehrenberg},
  number    = {42},
  publisher = {Universit{\"a}tsverlag Potsdam},
  address   = {Potsdam},
  issn      = {1617-5239},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-515034},
  pages     = {75 -- 87},
  year      = {2021},
  abstract  = {The Russian-Siberian journey, carried out with Alexander von Humboldt and Gustav Rose in 1829 coincided with a decisive phase in Christian Gottfried Ehrenberg's scientific career. His field diary and the drawings he made on the trip document his intensified focus on the study of microorganisms. The numerous observations on plant and animal geography show how Ehrenberg tested a combination of micro- and macro-perspectives that would shape his research on infusoria in the following decades: In addition to the task of classification at the microscope, Ehrenberg carried out worldwide comparative research on the distribution of microorganisms.},
  language  = {de}
}
@misc{MarkschiesPaesslerGroteetal.2021,
  author    = {Markschies, Christoph and P{\"a}ßler, Ulrich and Grote, Mathias and Greenwood MacKinney, Anne and Kusber, Wolf-Henning and Jahn, Regine and Damaschun, Ferdinand and B{\"o}hme, Katrin},
  title     = {HiN : Alexander von Humboldt im Netz = Christian Gottfried Ehrenberg},
  volume    = {XXII},
  number    = {42},
  editor    = {Ette, Ottmar and Knobloch, Eberhard and P{\"a}ßler, Ulrich},
  publisher = {Universit{\"a}tsverlag Potsdam},
  address   = {Potsdam},
  issn      = {2568-3543},
  doi       = {10.25932/publishup-50141},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-501413},
  pages     = {169},
  year      = {2021},
  abstract  = {-Christoph Markschies: Geleitwort -Ulrich P{\"a}ßler: Christian Gottfried Ehrenberg: Lebensbilder eines Naturforschers -Mathias Grote: „Aus dem Kleinen bauen sich die Welten" - Christian Gottfried Ehrenbergs {\"o}kologische Mikrobiologie avant la lettre -Anne Greenwood MacKinney: Die Inszenierung naturforschender Gelehrsamkeit beim Sammeln: Christian Gottfried Ehrenbergs und Wilhelm Hemprichs nordafrikanische Forschungsreise (1820 - 1825) -Ulrich P{\"a}ßler: Reisen im Nahen Osten. Zeichnungen -Ulrich P{\"a}ßler: Christian Gottfried Ehrenberg und die Biogeographie: Die russisch-sibirische Reise mit Alexander von Humboldt (1829) -Ulrich P{\"a}ßler: Russisch-Sibirische Reise. Zeichnungen -Wolf-Henning Kusber, Regine Jahn: Christian Gottfried Ehrenbergs Zeichnungen: Eine fr{\"u}he wissenschaftliche Dokumentation mikroskopischer Organismen -Ferdinand Damaschun: Christian Gottfried Ehrenberg und die Entwicklung der Mikroskop-Technik im 19. Jahrhundert -Ulrich P{\"a}ßler: Die Reise ins Kleinste der Natur. Zeichnungen -Katrin B{\"o}hme: Das große Ganze: Christian Gottfried Ehrenberg und die Gesellschaft Naturforschender Freunde zu Berlin},
  language  = {de}
}