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 - 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 - 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 - 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 - 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 - TY - JOUR A1 - Puppe, Daniel A1 - Kaczorek, Danuta A1 - Schaller, Jörg A1 - Barkusky, Dietmar A1 - Sommer, Michael T1 - Crop straw recycling prevents anthropogenic desilication of agricultural soil-plant systems in the temperate zone BT - results from a long-term field experiment in NE Germany JF - Geoderma : an international journal of soil science N2 - Due to the fact that silicon (Si) increases the resistance of plants against diverse abiotic and biotic stresses, Si nowadays is categorized as beneficial substance for plants. However, humans directly influence Si cycling on a global scale. Intensified agriculture and corresponding harvest-related Si exports lead to Si losses in agricultural soils. This anthropogenic desilication might be a big challenge for modern agriculture. However, there is still only little knowledge about Si cycling in agricultural systems of the temperate zone, because most studies focus on rice and sugarcane production in (sub)tropical areas. Furthermore, many studies are performed for a short term only, and thus do not provide the opportunity to analyze slow changes in soil-plant systems (e.g., desilication) over long periods. We analyzed soil and plant samples from an ongoing long-term field experiment (established 1963) in the temperate zone (NE Germany) to evaluate the effects of different nitrogen-phosphoruspotassium (NPK) fertilization rates and crop straw recycling (i.e., straw incorporation) on anthropogenic desilication in the long term. Our results clearly show that crop straw recycling not only prevents anthropogenic desilication (about 43-60% of Si exports can be saved by crop straw recycling in the long term), but also replenishes plant available Si stocks of agricultural soil-plant systems. Furthermore, we found that a reduction of N fertilization rates of about 69% is possible without considerable biomass losses. This economy of the need for N fertilizers potentially can be combined with the benefits of crop straw recycling, i.e., enhancement of carbon sequestration via straw inputs and prevention of anthropogenic desilication of agricultural soil-plant systems. Thus crop straw recycling might have the potential to act as key management practice in sustainable, low fertilization agriculture in the temperate zone in the future. KW - Sustainable crop production KW - Straw incorporation KW - Phytoliths KW - Silicon exports KW - Plant available Si Y1 - 2021 U6 - https://doi.org/10.1016/j.geoderma.2021.115187 SN - 0016-7061 SN - 1872-6259 VL - 403 PB - Elsevier CY - Amsterdam 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 - Leue, Martin A1 - Sommer, Michael A1 - Schaller, Jörg A1 - Kaczorek, Danuta T1 - Auto-fluorescence in phytoliths BT - a mechanistic understanding derived from microscopic and spectroscopic analyses JF - Frontiers in Environmental Science N2 - The detection of auto-fluorescence in phytogenic, hydrated amorphous silica depositions (phytoliths) has been found to be a promising approach to verify if phytoliths were burnt or not, especially in archaeological contexts. However, it is unknown so far at what temperature and how auto-fluorescence is induced in phytoliths. We used fluorescence microscopy, scanning electron microscope-energy dispersive X-ray spectroscopy (SEM-EDX), and Fourier transform infrared spectroscopy to analyze auto-fluorescence in modern phytoliths extracted from plant samples or in intact leaves of winter wheat. Leaves and extracted phytoliths were heated at different temperatures up to 600 degrees C. The aims of our experiments were i) to find out what temperature is needed to induce auto-fluorescence in phytoliths, ii) to detect temperature-dependent changes in the molecular structure of phytoliths related to auto-fluorescence, and iii) to derive a mechanistic understanding of auto-fluorescence in phytoliths. We found organic compounds associated with phytoliths to cause auto-fluorescence in phytoliths treated at temperatures below approx. 400 degrees C. In phytoliths treated at higher temperatures, i.e., 450 and 600 degrees C, phytolith auto-fluorescence was mainly caused by molecular changes of phytolith silica. Based on our results we propose that auto-fluorescence in phytoliths is caused by clusterization-triggered emissions, which are caused by overlapping electron clouds forming non-conventional chromophores. In phytoliths heated at temperatures above about 400 degrees C dihydroxylation and the formation of siloxanes result in oxygen clusters that serve as non-conventional chromophores in fluorescence events. Furthermore, SEM-EDX analyses revealed that extractable phytoliths were dominated by lumen phytoliths (62%) compared to cell wall phytoliths (38%). Our findings might be not only relevant in archaeological phytolith-based examinations, but also for studies on the temperature-dependent release of silicon from phytoliths and the potential of long-term carbon sequestration in phytoliths. KW - fluorescence microscopy KW - FTIR spectroscopy KW - SEM-EDX KW - burnt phytoliths; KW - carbon sequestration Y1 - 2022 U6 - https://doi.org/10.3389/fenvs.2022.915947 SN - 2296-665X VL - 10 PB - Frontiers Media CY - Lausanne ER - TY - JOUR A1 - Puppe, Daniel A1 - Sommer, Michael T1 - Experiments, uptake mechanisms, and functioning of silicon foliar fertilization BT - a review focusing on Maize, Rice, and Wheat JF - Advances in Agronomy ; 152 N2 - Silicon (Si) is considered as a quasiessential element for higher plants as its uptake increases plant growth and resistance against abiotic as well as biotic stresses. Foliar application of fertilizers generally is assumed to be a comparably environment-friendly form of fertilization because only small quantities are needed. The interest in foliar fertilization and the use of Si as a fertilizer in general increased significantly within the last decades, but there are only few publications dealing with the foliar application of Si at all. In the present review, the effects of Si foliar fertilization, including nano-Si fertilizers, on the three most important crops on a global scale, that is, maize, rice, and wheat, are summarized. Additionally, different pathways (i.e., cuticular pathways, stomata, and trichomes) of foliar uptake and functioning of Si foliar fertilizers against biotic (i.e., fungal diseases and harmful insects), as well as abiotic (i.e., water stress, macronutrient imbalance, and heavy metal toxicity) stressors are discussed. Future research should especially focus on (1) the gathering of empirical data from field and greenhouse experiments, (2) the intensification of co-operations between practitioners and scientists, (3) interdisciplinary research, and (4) the analysis of results from multiple studies (meta-analysis, big data) to fully understand effects, uptake, and functioning of Si foliar fertilizers and to evaluate their potential in modern sustainable agriculture concepts. Y1 - 2018 SN - 978-0-12-815171-6 U6 - https://doi.org/10.1016/bs.agron.2018.07.003 SN - 0065-2113 VL - 152 SP - 1 EP - 49 PB - Elsevier CY - San Diego ER -