Dynamics of rare earth elements and associated major and trace elements during Douglas-fir (<i>Pseudotsuga menziesii</i>) and European beech (<i>Fagus sylvatica</i> L.) litter degradation

Abstract. Given the diverse physico-chemical properties of elements, we hypothesize that their incoherent distribution across leaf tissues, combined with distinct resistance to degradation each tissue exhibits, leads different turnover rates among elements. Moreover, litter layers varying ages produce chemical signatures in solution during wet degradation. To verify our hypothesis, Na, K, Mg, Mn, Ca, Pb, Al and Fe were analysed together rare earth elements (REE) solid fractions respective leachates fresh leaves two forested soils developed under Pseudotsuga menziesii Fagus sylvatica L. trees. The results from leaching experiment also compared situ REE composition soil solutions clarify impact processes may have on composition. Both tree species showed similar biogeochemical dominating element dynamics REE, Al, Pb preferentially retained material, comparison other cations, concentrations increased over time Accordingly, produced yields patterns leachates, indicating age play a role release In particular, evolution patterns, relative layers, allowed us deliver new findings fractionation mobilization decay. Specifically, was characterized by decrease Y/Ho ratio an increase LaN/YbN ratio. relationship between these ratios provided information species-specific degradation, Douglas-fir material showing lower resistance. During species, main differences highlighted help REE: (i) behaviour Eu appeared be linked Ca senescence (ii) organic acids more pronounced middle (MREE) enrichment leachates. Finally, primary control effect white fungi Ce solutions, which appears associated dissolution and/or direct transport Ce-enriched MnO2 accumulated surface old due metabolic functioning microorganisms. Similar MREE heavy (HREE) enrichments found probably higher affinity for acids, represent products matter