Pulse, Shunt and Storage: Hydrological Contraction Shapes Processing and Export of Particulate Organic Matter in River Networks

Abstract Streams and rivers act as landscape-scale bioreactors processing large quantities of terrestrial particulate organic matter (POM). This function is linked to their flow regime, which governs residence times, shapes reactivity controls the amount carbon (C) exported atmosphere coastal oceans. Climate change impacts regimes by increasing both flash floods droughts. Here, we used a modelling approach explore consequences lateral hydrological contraction, that is, reduction wet portion streambed, for POM decomposition transport at river network scale. Our model integrates seasonal leaf litter input generator POM, transient storage on dry streambed portions with associated ensuing changes in reactivity, dynamics through dendritic network. Simulations showed from its average increased due combination (1) low while stored streambeds, (2) shunting during flashy events. The sensitivity analysis further supported high contraction leads higher export regardless coefficient values, fresh differences between under conditions. study incorporates areas into pulse-shunt concept (Raymond others Ecology 97(1):5–16, 2016. https://doi.org/10.1890/14-1684.1 ), providing mechanistic framework testable predictions about storage, fluvial networks.