@article{PuppeEhrmannKaczoreketal.2015,
  author    = {Puppe, Daniel and Ehrmann, Otto and Kaczorek, Danuta and Wanner, Manfred and Sommer, Michael},
  title     = {The protozoic Si pool in temperate forest ecosystems - Quantification, abiotic controls and interactions with earthworms},
  series = {Geoderma : an international journal of soil science},
  volume    = {243},
  journal   = {Geoderma : an international journal of soil science},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0016-7061},
  doi       = {10.1016/j.geoderma.2014.12.018},
  pages     = {196 -- 204},
  year      = {2015},
  abstract  = {Biogenic silicon (BSI) pools influence Si cycling in terrestrial ecosystems. As research has been focused mainly on phytogenic BSi pools until now, there is only little information available on quantities of other BSi pools. There are no systematic studies on protozoic Si pools - here represented by idiosomic testate amoebae (TA) - and abiotic and biotic influences in temperate forest ecosystems. We selected ten old forests along a strong gradient in soil forming factors (especially parent material and climate), soil properties and humus forms. We quantified idiosomic Si pools, corresponding annual biosilicification, plant-available and amorphous Si fractions of topsoil horizons. Furthermore, we analyzed the potential influences of abiotic factors (e.g. soil pH) and earthworms on idiosomic Si pools. While idiosomic Si pools were relatively small (up to 5 kg Si ha(-1)), annual biosilicification rates of living TA (17-80 kg Si ha(-1)) were comparable to or even exceeded reported data of annual Si uptake by trees. Soil pH exerted a strong, non-linear control on plant-available Si. Surprisingly, no relationship between Si supply and idiosomic Si pools could be found (no Si limitation). Instead, idiosomic Si pools showed a strong, negative relationship to earthworm biomasses, which corresponded to humus forms. We concluded that earthworms control idiosomic Si pools in forest soils by direct (feeding, competition) and/or indirect mechanisms (e.g. change of habitat structure). Earthworms themselves were strongly influenced by soil pH: Below a threshold of pH 3.8 no endogeic or anecic earthworms existed. As soil pH is a result of weathering and acidification idiosomic Si pools are indirectly, but ultimately controlled by soil forming factors, mainly parent material and climate. (C) 2014 Elsevier B.V. All rights reserved.},
  language  = {en}
}
@article{PuppeWannerSommer2018,
  author    = {Puppe, Daniel and Wanner, Manfred and Sommer, Michael},
  title     = {Data on euglyphid testate amoeba densities, corresponding protozoic silicon pools, and selected soil parameters of initial and forested biogeosystems},
  series = {Data in brief},
  volume    = {21},
  journal   = {Data in brief},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {2352-3409},
  doi       = {10.1016/j.dib.2018.10.164},
  pages     = {1697 -- 1703},
  year      = {2018},
  abstract  = {The dataset in the present article provides information on protozoic silicon (Si) pools represented by euglyphid testate amoebae (TA) in soils of initial and forested biogeosystems. Protozoic Si pools were calculated from densities of euglyphid TA shells and corresponding Si contents. The article also includes data on potential annual biosilicification rates of euglyphid TA at the examined sites. Furthermore, data on selected soil parameters (e.g., readily-available Si, soil pH) and site characteristics (e.g., soil groups, climate data) can be found. The data might be interesting for researchers focusing on biological processes in Si cycling in general and euglyphid TA and corresponding protozoic Si pools in particular.},
  language  = {en}
}
@article{PuppeHoehnKaczoreketal.2016,
  author    = {Puppe, Daniel and H{\"o}hn, Axel and Kaczorek, Danuta and Wanner, Manfred and Sommer, Michael},
  title     = {As time goes by-Spatiotemporal changes of biogenic Si pools in initial soils of an artificial catchment in NE Germany},
  series = {Applied soil ecology : a section of agriculture, ecosystems \& environment},
  volume    = {105},
  journal   = {Applied soil ecology : a section of agriculture, ecosystems \& environment},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0929-1393},
  doi       = {10.1016/j.apsoil.2016.01.020},
  pages     = {9 -- 16},
  year      = {2016},
  language  = {en}
}