Species-specific stoichiometric effects of leaf litter on algal growth,
production, and cell quotas
Abstract
Dissolved organic matter and nutrients released from forest leaf litter
are important cross-ecosystem resources that support freshwater
ecosystems. Dissolved organic matter released from leaf litter is one of
the allochthonous sources for heterotrophic organisms in freshwater
communities. However, the role of macro- and micronutrients released
from leaf litter in producing autochthonous organic matter in aquatic
ecosystems is not necessarily well understood. In this study, therefore,
we investigated how dissolved nutrients released from leaf litter affect
the algal growth, biomass production, and cell elemental quotas.
Specifically, we focused on the responses of the green algae to TDN,
TDP, and micronutrients released from the leaf litter of 11 temperate
tree species. We found that the algal growth rate increased with TDP
when micronutrients were amended. In contrast, the algal biomass
production increased with TDN, regardless of micronutrient amendment.
Micronutrient limitation of algal growth rate was found in the leaf
litter leachates from oak, Japanese elm, and Japanese hemlock. However,
algal biomass production was limited by micronutrients only in the leaf
litter leachate from Japanese hemlock. More importantly, leaf litter
leachates from different tree species altered algal cell quotas and
C:N:P ratios, which would affect secondary production. These results
suggest that forest vegetation change or succession affect the quantity
and quality of autochthonous organic matter and thus the mass transfer
efficiency in the aquatic community by changing the stoichiometry of
nutrient input from the leaf litter.