@article{SchallerPuppeKaczoreketal.2021,
  author    = {Schaller, J{\"o}rg and Puppe, Daniel and Kaczorek, Danuta and Ellerbrock, Ruth and Sommer, Michael},
  title     = {Silicon cycling in soils revisited},
  series = {Plants : open access journal},
  volume    = {10},
  journal   = {Plants : open access journal},
  number    = {2},
  publisher = {MDPI},
  address   = {Basel},
  issn      = {2223-7747},
  doi       = {10.3390/plants10020295},
  pages     = {33},
  year      = {2021},
  abstract  = {Silicon (Si) speciation and availability in soils is highly important for ecosystem functioning, because Si is a beneficial element for plant growth. Si chemistry is highly complex compared to other elements in soils, because Si reaction rates are relatively slow and dependent on Si species. Consequently, we review the occurrence of different Si species in soil solution and their changes by polymerization, depolymerization, and condensation in relation to important soil processes. We show that an argumentation based on thermodynamic endmembers of Si dependent processes, as currently done, is often difficult, because some reactions such as mineral crystallization require months to years (sometimes even centuries or millennia). Furthermore, we give an overview of Si reactions in soil solution and the predominance of certain solid compounds, which is a neglected but important parameter controlling the availability, reactivity, and function of Si in soils. We further discuss the drivers of soil Si cycling and how humans interfere with these processes. The soil Si cycle is of major importance for ecosystem functioning; therefore, a deeper understanding of drivers of Si cycling (e.g., predominant speciation), human disturbances and the implication for important soil properties (water storage, nutrient availability, and micro aggregate stability) is of fundamental relevance.},
  language  = {en}
}
@article{AttermeyerPremkeHornicketal.2013,
  author    = {Attermeyer, Katrin and Premke, Katrin and Hornick, Thomas and Hilt, Sabine and Grossart, Hans-Peter},
  title     = {Ecosystem-level studies of terrestrial carbon reveal contrasting bacterial metabolism in different aquatic habitats},
  series = {Ecology : a publication of the Ecological Society of America},
  volume    = {94},
  journal   = {Ecology : a publication of the Ecological Society of America},
  number    = {12},
  publisher = {Wiley},
  address   = {Washington},
  issn      = {0012-9658},
  doi       = {10.1890/13-0420.1},
  pages     = {2754 -- 2766},
  year      = {2013},
  abstract  = {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.},
  language  = {en}
}