Dissolved C, N, and P release efficiency from temperate tree leaf litter

Dissolved organic matter and inorganic nutrients released from forest leaf
litter through leaching are important energy and nutrient sources that
support the production of aquatic food webs. Leaf litter-derived dissolved
organic carbon (DOC) is a critical energy source for aquatic heterotrophic
microbes, and inorganic nitrogen and phosphorus can enhance primary
production. In this study, we experimentally measured the release
efficiencies and amounts of DOC, total dissolved nitrogen (TDN) and total
dissolved phosphorus (TDP) of the leaf litter from 11 temperate tree
species by soaking the leaf litter in water for 28 days. We found that the
maximal release efficiency (% of element released per estimated mass of
the element) was the highest for P and lowest for N. These efficiencies
were species-specific. Additionally, the DOC:TDP, DOC:TDN, and TDN:TDP
ratios varied among the leachate of different leaf litter species. DOC:TDP
increased with the C:P ratio in leaf litter biomass but is considerably
lower; TDN:TDP was lower than the N:P ratio in leaf litter biomass as
well; DOC:TDN ratio was higher than the C:N ratio in leaf litter biomass.
These results suggest that the ratios of DOC to dissolved N and P
nutrients released into water are related to, but not the same as, the
stoichiometry of leaf litter biomass. Based on these findings, we
concluded that changes in the vegetation with different leaf litter
stoichiometry can alter the relative importance of detrital and grazing
food chains in aquatic ecosystems.