Stoichiometry of carbon, nitrogen, and phosphorus released from the leaf
litter of various temperate tree species
Abstract
Dissolved organic matter and inorganic nutrients released from forest
leaf litter through leaching are the important energy and nutrient
sources that support the production of aquatic food webs. Litter
leachate-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
dissolved organic 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 and
TDN:TDP ratios varied among the leachates of different leaf litter
species and were considerably lower than the C:P and N:P ratios in leaf
litter biomass; the DOC:TDN ratio was higher than the C:N ratio in leaf
litter biomass. These results suggested that the ratios of organic
carbon to nutrients dissolved into water cannot be fully elucidated
using the elemental ratios of leaf litter mass. Based on these findings,
we concluded that changes in the vegetations with different leaf litter
stoichiometry can alter the relative importance of detrital and grazing
food chains in aquatic ecosystems.