Long-term stoichiometry and fates highlight animal egestion as nutrient repackaging, not recycling, in aquatic ecosystems

1. Animal defecation, or egestion, is a pronounced transformation of organic matter in many ecosystems. However, because egesta have been presumed recalcitrant and low-nutrient, their significance and variability as an animal nutrient flux in aquatic settings - especially relative to mineralization via excretion - are poorly known. 2. We compared carbon (C), nitrogen (N), and phosphorus (P) dynamics over short- to long-term (up to 107 days) microbial decomposition of egesta from the aquatic shredders Allocapnia spp., Lirceus spp., and Tipula spp. fed low- or high-P content Platanus occidentalis litter to investigate roles of egesta in aquatic nutrient dynamics. 3. Tipula produced N- and P-deplete egesta of higher N:P compared to Lirceus and Allocapnia, and high-P diets increased egesta P content compared to low-P diets. Despite measurable C losses to decomposition, these differences in nutrient content persisted through decomposition, showing diet and species control both immediate and ...