TY - JOUR A1 - Kaczorek, Danuta A1 - Puppe, Daniel A1 - Busse, Jacqueline A1 - Sommer, Michael T1 - Effects of phytolith distribution and characteristics on extractable silicon fractions in soils under different vegetation - An exploratory study on loess JF - Geoderma : an international journal of soil science N2 - The significance of phytoliths for the control of silicon (Si) fluxes from terrestrial to aquatic ecosystems has been recognized as a key factor. Humankind actively influences Si fluxes by intensified land use, i.e., agriculture and forestry, on a global scale. We hypothesized phytolith distribution and assemblages in soils of agricultural and forestry sites to be controlled by vegetation (which is directed by land use) with direct effects on extractable Si fractions driven mainly by phytolith characteristics, i.e., dissolution status (dissolution signs) and morphology (morphotype proportions). To test our hypothesis we combined different chemical extraction methods (calcium chloride, ammonium oxalate, Tiron) for the quantification of different Si fractions (plant available Si, Si adsorbed to/occluded in pedogenic oxides/hydroxides, amorphous Si) and microscopic techniques (light microscopy, confocal laser scanning microscopy, scanning electron microscopy) for detailed analyses of phytoliths extracted using gravimetric separation (physical extraction) from exemplary loess soils of agricultural (arable land and grassland/meadow) and forestry (beech and pine) sites in Poland. We found differences in dissolution signs, morphotype proportions, and vertical distribution of phytoliths in soil horizons per site. In general, dominant morphotypes of assignable phytoliths in the studied soil profiles were elongate phytoliths and short cells, both of which are typical for grass-dominated vegetation. However, the organic layers of forest soils were dominated by globular phytoliths, which are typical indicators for mosses. As expected soil horizons under different vegetation generally were characterized by differences in extractable Si fractions, especially in the upper soil horizons. However, phytogenic Si pools counter-intuitively showed no correlations with chemically extracted Si fractions and soil pH at all. Our findings indicate that it is necessary to combine microscopic analyses and Si extraction techniques for examinations of Si cycling in biogeosystems, because extractions of Si fractions alone do not allow drawing any conclusions about phytolith characteristics or interactions between phytolith pools and chemically extractable Si fractions and do not necessarily reflect phytogenic Si pool quantities in soils and vice versa. KW - Phytolith dissolution KW - Phytolith morphotypes KW - Si extraction KW - Surface roughness parameters KW - Si cycling Y1 - 2019 U6 - https://doi.org/10.1016/j.geoderma.2019.113917 SN - 0016-7061 SN - 1872-6259 VL - 356 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Sommer, Michael A1 - Kaczorek, Danuta A1 - Kuzyakov, Yakov A1 - Breuer, Jörn T1 - Silicon pools and fluxes in soils and landscapes : a review N2 - Silicon (Si) is the second-most abundant element in the earth's crust. In the pedosphere, however, huge spans of Si contents occur mainly caused by Si redistribution in soil profiles and landscapes. Here, we summarize the current knowledge on the different pools and fluxes of Si in soils and terrestrial biogeosystems. Weathering and subsequent release of soluble Si may lead to (1) secondarily bound Si in newly formed Al silicates, (2) amorphous silica precipitation on surfaces of other minerals, (3) plant uptake, formation of phytogenic Si, and subsequent retranslocation to soils, (4) translocation within soil profiles and formation of new horizons, or (5) translocation out of soils (desilication). The research carried out hitherto focused on the participation of Si in weathering processes, especially in clay neoformation, buffering mechanisms for acids in soils or chemical denudation of landscapes. There are, however, only few investigations on the characteristics and controls of the low-crystalline, almost pure silica compounds formed during pedogenesis. Further, there is strong demand to improve the knowledge of (micro)biological and rhizosphere processes contributing to Si mobilization, plant uptake, and formation of phytogenic Si in plants, and release due to microbial decomposition. The contribution of the biogenic Si sources to Si redistribution within soil profiles and desilication remains unknown concerning the pools, rates, processes, and driving forces. Comprehensive studies considering soil hydrological, chemical, and biological processes as well as their interactions at the scale of pedons and landscapes are necessary to make up and model the Si balance and to couple terrestrial processes with Si cycle of limnic, fluvial, or marine biogeosystems Y1 - 2006 ER - TY - JOUR A1 - Kaczorek, Danuta A1 - Bruemmer, Gerhard W. A1 - Sommer, Michael T1 - Content and binding forms of heavy metals, aluminium and phosphorus in bog iron ores from Poland N2 - Bog iron ores are widespread in Polish wetland soils used as meadows or pastures. They are suspected to contain high concentrations of heavy metals, which are precipitated together with Fe along a redox gradient. Therefore, soils with bog iron ore might be important sources for a heavy metal transfer from meadow plants into the food chain. However, this transfer depends on the different binding forms of heavy metals. The binding forms were quantified by sequential extraction analysis of heavy metals (Fe, Mn, Cr, Co, Ni, Cd, Pb) as well as Al and P on 13 representative samples of bog iron ores from central and southwestern Poland. Our results showed total contents of Cr, Co, Ni, Zn, Cd, and Pb not to exceed the natural values for sandy soils from Poland. Only the total Mn was slightly higher. The highest contents of all heavy metals have,been obtained in iron oxide fractions V (occluded in noncrystalline and poorly crystalline Fe oxides) and VI (occluded in crystalline Fe oxides). The results show a distinct relationship between the content of Fe and the quantity of Zn and Pb as well R Water soluble as well as plant available fractions were below the detection limit in most cases. From this we concluded bog iron ores not to be an actual, important source of heavy metals in the food chain. However, a remobilization of heavy metals might occur due to any reduction of iron oxides in bog iron ores, for example, by rising groundwater levels. Y1 - 2009 UR - https://www.soils.org/publications/jeq U6 - https://doi.org/10.2134/Jeq2008.0125 SN - 0047-2425 ER - TY - JOUR A1 - Steinhoefel, Grit A1 - Breuer, Jörn A1 - von Blanckenburg, Friedhelm A1 - Horn, Ingo A1 - Kaczorek, Danuta A1 - Sommer, Michael T1 - Micrometer silicon isotope diagnostics of soils by UV femtosecond laser ablation JF - Chemical geology : official journal of the European Association for Geochemistry N2 - This study presents the first Si isotope data of the principle Si pools in soils determined by a UV femtosecond laser ablation system coupled to a multicollector inductively coupled plasma mass spectrometer (MC-ICP-MS). This method reveals accurate and precise Si isotope data on bulk materials, and at high spatial resolution, on the mineral scale. The following Si pools have been investigated: a) the Si source to soils on all major silicate minerals on thin sections from bedrock fragments in the soil profiles; b) bulk soils (particle size <2 mm) after fusion to glass beads with an iridium-strip heater or pressed into powder pellets: c) separated clay fractions as pressed powder pellets and e) separated phytoliths as pressed powder pellets. Multiple analyses of three rock standards, BHVO-2, AGV-1 and RGM-1 as fused glass beads and as pressed powder pellets, reveal delta(30)Si values within the expected range of igneous rocks. The MPI-DING reference glass KL2-G exhibits the same Si isotope composition after remelting by an iridium-strip heater showing that this technique does not alter the isotope composition of the glass. We used this approach to investigated two immature Cambisols developed on sandstone and paragneiss in the Black Forest (Germany), respectively. Bulk soils show a largely uniform Si isotope signature for different horizons and locations, which is close to those of primary quartz and feldspar with delta(30)Si values around -0.4 parts per thousand. Soil clay formation is associated with limited Si mobility, which preserves initial Si isotope signatures of parental minerals. An exception is the organic horizon of the paragneiss catchment where intense weathering leads to a high mobility of Si and significant negative isotope signatures as low as to -1.00 parts per thousand in bulk soils. Biogenic opal in the form of phytoliths, exhibits negative Si isotope signatures of about -0.4 parts per thousand. These results demonstrate that UV femtosecond laser ablation MC-ICP-MS provides a tool to characterize the Si isotope signature of the principle Si pools left behind after weathering and Si transport have altered soils. These results can now serve as a fingerprint of the residual solids that can be used to explain the isotope composition of dissolved Si in soil solutions and river water, which is mostly enriched in the heavy isotopes. KW - Silicon isotopes KW - Soils KW - UV femtosecond laser ablation KW - MC-ICP-MS Y1 - 2011 U6 - https://doi.org/10.1016/j.chemgeo.2011.05.013 SN - 0009-2541 VL - 286 IS - 3-4 SP - 280 EP - 289 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Ehrmann, Otto A1 - Puppe, Daniel A1 - Wanner, Manfred A1 - Kaczorek, Danuta A1 - Sommer, Michael T1 - Testate amoebae in 31 mature forest ecosystems - Densities and micro-distribution in soils JF - European journal of protistology N2 - We studied testate amoebae and possible correlated abiotic factors in soils of 31 mature forest ecosystems using an easily applicable and spatially explicit method. Simple counting on soil thin-sections with a light microscope resulted in amoeba densities comparable to previously reported values, i.e. 0.1 x 10(8) to 11.5 x 10(8) individuals m(-2) (upper 3 cm of soil). Soil moisture and soil acidity seem to be correlated with amoeba densities. At sites of moderate soil moisture regimes (SMR 2-7) we found higher densities of testate amoebae at pH < 4.5. At wetter sites (SMR >= 8) higher individual densities were recorded also at less acidic sites. The in situ description of amoebae, based on the analysis of a complete soil thin-section, showed a relatively uniform spatial micro-distribution throughout the organic and mineral soil horizons (no testate amoeba clusters). We discuss the pros and cons of the soil thin-section method and suggest it as an additional tool to improve knowledge of the spatial micro-distribution of testate amoebae. KW - Microhabitats KW - Soil thin-section KW - Soil moisture regimes KW - Soil reaction Y1 - 2012 U6 - https://doi.org/10.1016/j.ejop.2012.01.003 SN - 0932-4739 VL - 48 IS - 3 SP - 161 EP - 168 PB - Elsevier CY - Jena ER - TY - JOUR A1 - Puppe, Daniel A1 - Kaczorek, Danuta A1 - Wanner, Manfred A1 - Sommer, Michael T1 - Dynamics and drivers of the protozoic Si pool along a 10-year chronosequence of initial ecosystem states JF - Ecological engineering : the journal of ecotechnology N2 - The size and dynamics of biogenic silicon (BSi) pools influence silicon (Si) fluxes from terrestrial to aquatic ecosystems. The research focus up to now was on the role of plants in Si cycling. In recent studies on old forests annual biosilicification rates of idiosomic testate amoebae (i.e. TA producing self-secreted silica shells) were shown to be of the order of Si uptake by trees. However, no comparable data exist for initial ecosystems. We analyzed the protozoic BSi pool (idiosomic TA), corresponding annual biosilicification rates and readily available and amorphous Si fractions along a 10-year chronosequence in a post-mining landscape in Brandenburg, Germany. Idiosomic Si pools ranged from 3 to 680 g Si ha(-1) and were about 3-4 times higher at vegetated compared to uncovered spots. They increased significantly with age and were related to temporal development of soil chemical properties. The calculation of annual biosilicification resulted in maxima between 2 and 16 kg Si ha(-1) with rates always higher at vegetated spots. Our results showed that the BSi pool of idiosomic TA is built up rapidly during the initial phases of ecosystem development and is strongly linked to plant growth. Furthermore, our findings highlight the importance of TA for Si cycling in young artificial ecosystems. (C) 2014 Elsevier B.V. All rights reserved. KW - Idiosomic Si pool KW - Amorphous silica KW - Terrestrial ecosystem development KW - Artificial catchment KW - Si fractions KW - Biosilicification Y1 - 2014 U6 - https://doi.org/10.1016/j.ecoleng.2014.06.011 SN - 0925-8574 SN - 1872-6992 VL - 70 SP - 477 EP - 482 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Puppe, Daniel A1 - Höhn, Axel A1 - Kaczorek, Danuta A1 - Wanner, Manfred A1 - Sommer, Michael T1 - As time goes by-Spatiotemporal changes of biogenic Si pools in initial soils of an artificial catchment in NE Germany JF - Applied soil ecology : a section of agriculture, ecosystems & environment KW - Biogenic silica KW - Diatom frustule KW - Testate amoeba shell KW - Sponge spicule KW - Initial ecosystem Y1 - 2016 U6 - https://doi.org/10.1016/j.apsoil.2016.01.020 SN - 0929-1393 SN - 1873-0272 VL - 105 SP - 9 EP - 16 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Puppe, Daniel A1 - Ehrmann, Otto A1 - Kaczorek, Danuta A1 - Wanner, Manfred A1 - Sommer, Michael T1 - The protozoic Si pool in temperate forest ecosystems - Quantification, abiotic controls and interactions with earthworms JF - Geoderma : an international journal of soil science N2 - 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. KW - Biogenic silica KW - Testate amoebae KW - Biosilicification KW - Terrestrial Si cycle KW - Si fractions KW - Humus forms Y1 - 2015 U6 - https://doi.org/10.1016/j.geoderma.2014.12.018 SN - 0016-7061 SN - 1872-6259 VL - 243 SP - 196 EP - 204 PB - Elsevier CY - Amsterdam ER - TY - GEN A1 - Puppe, Daniel A1 - Höhn, Axel A1 - Kaczorek, Danuta A1 - Wanner, Manfred A1 - Wehrhan, Marc A1 - Sommer, Michael T1 - How big is the influence of biogenic silicon pools on short-term changes in water-soluble silicon in soils? BT - Implications from a study of a 10-year-old soil–plant system T2 - Postprints der Universität Potsdam : Mathematisch Naturwissenschaftliche Reihe N2 - The significance of biogenic silicon (BSi) pools as a key factor for the control of Si fluxes from terrestrial to aquatic ecosystems has been recognized for decades. However, while most research has been focused on phytogenic Si pools, knowledge of other BSi pools is still limited. We hypothesized that different BSi pools influence short-term changes in the water-soluble Si fraction in soils to different extents. To test our hypothesis we took plant (Calamagrostis epigejos, Phragmites australis) and soil samples in an artificial catchment in a post-mining landscape in the state of Brandenburg, Germany. We quantified phytogenic (phytoliths), protistic (diatom frustules and testate amoeba shells) and zoogenic (sponge spicules) Si pools as well as Tironextractable and water-soluble Si fractions in soils at the beginning (t(0)) and after 10 years (t(10)) of ecosystem development. As expected the results of Tiron extraction showed that there are no consistent changes in the amorphous Si pool at Chicken Creek (Huhnerwasser) as early as after 10 years. In contrast to t(0) we found increased water-soluble Si and BSi pools at t(10); thus we concluded that BSi pools are the main driver of short-term changes in water-soluble Si. However, because total BSi represents only small proportions of water-soluble Si at t(0) (< 2 %) and t(10) (2.8-4.3 %) we further concluded that smaller (< 5 mu m) and/or fragile phytogenic Si structures have the biggest impact on short-term changes in water-soluble Si. In this context, extracted phytoliths (> 5 mu m) only amounted to about 16% of total Si con-tents of plant materials of C. epigejos and P. australis at t(10); thus about 84% of small-scale and/or fragile phytogenic Si is not quantified by the used phytolith extraction method. Analyses of small-scale and fragile phytogenic Si structures are urgently needed in future work as they seem to represent the biggest and most reactive Si pool in soils. Thus they are the most important drivers of Si cycling in terrestrial biogeosystems. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 633 KW - brook experimental forest KW - protozoic Si pool KW - testate amebas KW - biochemical cycle KW - temperate forest KW - amorphous silica KW - dissolution KW - carbon KW - phytoliths KW - surface Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-417141 IS - 633 SP - 5239 EP - 5252 ER - TY - JOUR A1 - Puppe, Daniel A1 - Höhn, Axel A1 - Kaczorek, Danuta A1 - Wanner, Manfred A1 - Wehrhan, Marc A1 - Sommer, Michael T1 - How big is the influence of biogenic silicon pools on short-term changes in water-soluble silicon in soils? Implications from a study of a 10-year-old soil-plant system JF - Biogeosciences N2 - The significance of biogenic silicon (BSi) pools as a key factor for the control of Si fluxes from terrestrial to aquatic ecosystems has been recognized for decades. However, while most research has been focused on phytogenic Si pools, knowledge of other BSi pools is still limited. We hypothesized that different BSi pools influence short-term changes in the water-soluble Si fraction in soils to different extents. To test our hypothesis we took plant (Calamagrostis epigejos, Phragmites australis) and soil samples in an artificial catchment in a post-mining landscape in the state of Brandenburg, Germany. We quantified phytogenic (phytoliths), protistic (diatom frustules and testate amoeba shells) and zoogenic (sponge spicules) Si pools as well as Tironextractable and water-soluble Si fractions in soils at the beginning (t(0)) and after 10 years (t(10)) of ecosystem development. As expected the results of Tiron extraction showed that there are no consistent changes in the amorphous Si pool at Chicken Creek (Huhnerwasser) as early as after 10 years. In contrast to t(0) we found increased water-soluble Si and BSi pools at t(10); thus we concluded that BSi pools are the main driver of short-term changes in water-soluble Si. However, because total BSi represents only small proportions of water-soluble Si at t(0) (< 2 %) and t(10) (2.8-4.3 %) we further concluded that smaller (< 5 mu m) and/or fragile phytogenic Si structures have the biggest impact on short-term changes in water-soluble Si. In this context, extracted phytoliths (> 5 mu m) only amounted to about 16% of total Si con-tents of plant materials of C. epigejos and P. australis at t(10); thus about 84% of small-scale and/or fragile phytogenic Si is not quantified by the used phytolith extraction method. Analyses of small-scale and fragile phytogenic Si structures are urgently needed in future work as they seem to represent the biggest and most reactive Si pool in soils. Thus they are the most important drivers of Si cycling in terrestrial biogeosystems. Y1 - 2017 U6 - https://doi.org/10.5194/bg-14-5239-2017 SN - 1726-4170 SN - 1726-4189 VL - 14 PB - Copernicus CY - Göttingen ER -