Light and dissolved phosphorus interactively affect microbial metabolism, stoichiometry and decomposition of leaf litter

摘要: Summary In aquatic settings, light can stimulate algal growth to affect microbial transformation of organic substrates. These effects may depend on dissolved nutrients that differentially constrain autotrophy and heterotrophy drive contrasting carbon (C) phosphorus (P) dynamics during decomposition. We incubated sugar maple (Acer saccharum) litter under three P amendments (0, 50 or 500 μg L−1 P) two levels (14 475 μmol photons m−2 s−1) in laboratory microcosms. We measured chlorophyll a, respiration net metabolism, carbon:nitrogen (C:N) C:P content, uptake release decomposition over 134 days. Elevated increased biomass the high-light treatment magnified low- treatments, respectively. Litter C:N declined as increased, was further reduced by high only highest treatment. Microbial fluxes peaked moderate light, whereas were consistently low throughout experiment. The percent released significantly higher light. High stimulated but slowed P, suggesting weakened priming decomposition. Our study suggests factors controlling degree versus matter, such nutrient availability, interactively shift C decomposition.