Biogeochemistry ; forest; Dissolved organic matter; Nutrient cycle; Enzyme; Phosphorus; soil
Brödlin Dominik, Kaiser Klaus, Hagedorn Frank (2019), Divergent Patterns of Carbon, Nitrogen, and Phosphorus Mobilization in Forest Soils, in Frontiers in Forests and Global Change
, 2, 1-16.
Brödlin Dominik, Kaiser Klaus, Kessler Arnim, Hagedorn Frank (2019), Drying and rewetting foster phosphorus depletion of forest soils, in Soil Biology and Biochemistry
, 128, 22-34.
Bol Roland, Julich Dorit, Brödlin Dominik, Siemens Jan, Kaiser Klaus, Dippold Michaela Anna, Spielvogel Sandra, Zilla Thomas, Mewes Daniela, von Blanckenburg Friedhelm, Puhlmann Heike, Holzmann Stefan, Weiler Markus, Amelung Wulf, Lang Friederike, Kuzyakov Yakov, Feger Karl-Heinz, Gottselig Nina, Klumpp Erwin, Missong Anna, Winkelmann Carola, Uhlig David, Sohrt Jakob, von Wilpert Klaus, Bei Wu, HagedornFrank (2016), Dissolved and colloidal phosphorus fluxes in forest ecosystems-an almost blind spot in ecosystem research, in Journal of Plant Nutrition and Soil Science
, 179(4), 425-438.
As mineral sources of phosphorus are becoming increasingly scarce with progressing ecosystem development, forests start to recycle organic phosphorus. Inorganic phosphorus forms tend to be bound strongly to secondary minerals, thus, they are hardly available to plants and are not leached from soil. Instead, phosphorus leaching losses tend to be governed by mobile organic forms, in whatever state the ecosystem is. However, very little is known on the composition, mobility, and bioavailbaility of dissolved organic phosphorus (DOP). Microbial compounds such as nucleotides and nucleic acids are probably the most mobile fraction of DOP in soils, while plant-derived compounds, such as phytate, are less prone to leaching. However, these potentially mobile microbial compounds are enzymatically hydrolysable, and thus, they may be taken up by plants, which reduces DOP leaching losses from recycling ecosystems.Our proposed project aims at identifying the chemical characteristics of DOP compounds controlling their mobility, the environmental controls on DOP composition, and if DOP compounds are plant available. We will collect forest floor seepage water and solutions from mineral soils along the SPP1685-gradient of phosphorus availability. These solutions will be analyzed for chemical organic phosphorus species, using spectroscopic methods (basically NMR, complemented by XPS and XANES analyses on selected samples), and for enzymatic release of the phosphorus contained (in combination with spectroscopic methods). This approach will inform on mobile and labile dissolved organic phosphorus compounds. Similar analyses will be carried out on solutions deriving from other proposed SPP-experiments on potential controls (drought, pH) on dissolved phosphorus release. Laboratory assays will be conducted to estimate the potential mobility of organic phosphorus species (sorption experiments, in combination with spectroscopic methods) as well as experiments with 13C, 14C and 33P labeled compounds. The latter will address the potential plant uptake of DOP, either after enzymatic hydrolysis or by direct uptake of small molecules.