Silicon controls microbial decay and nutrient release of grass litter during aquatic decomposition
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The decomposition rate of plant litter is important for the carbon cycle. Element stoichiometry and hardly degradable carbon compounds are main factors controlling the decomposition rate of plant litter. Recent research has linked these factors to silicon availability during plant growth, but no research focused on the effect of silicon on litter decomposition. We therefore conducted a batch experiment to assess the effect of silicon availability to plants on litter degradation, nutrient release and multi elemental stoichiometry. Experiments were conducted in the presence or absence of invertebrate shredders (Gammarus pulex). We show that nutrient content (affected by silicon availability during plant growth) has a strong impact on nutrient turnover, while DOC, N, and Mn were mainly controlled by invertebrate feeding. The carbon turnover during microbial litter decay was strongly influenced by the silicon availability during plant growth, with quicker potential C turnover of litter with higher silicon content. In both Si-rich and Si-poor litter, feeding by invertebrate shredders positively impacted turnover rates, but effects were less pronounced in Si-rich litter. It can be concluded that silicon availability in wetlands dominated by reed plays an important role in carbon sequestration, nutrient cycling, and remobilization during aquatic litter decay.
KeywordsCarbon cycle Nutrient remobilization Silica Stoichiometry Wetland
The authors are grateful to Mr. T. Pust for laboratory and field assistance, Mrs. R. Schulze at the Institute of Bioanalytical Chemistry, Dresden University of Technology, for ICP-OES measurements and Mr. A. Weiske for all other measurements. Eric Struyf would like to thank FWO (Research Foundation Flanders) for personal post-doc funding. Furthermore, Eric Struyf acknowledges BELSPO for funding IAP project SOGLO.
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