Effects of nitrogen enrichment on zooplankton biomass and N:P recycling ratios across a DOC gradient in northern-latitude lakes

Abstract We used data from whole-lake studies to assess how changes in food quantity (phytoplankton biomass) and quality community composition, seston C:P N:P) with N fertilization affect zooplankton biomass, composition C:N:P stoichiometry, their N:P recycling ratio along a gradient lake DOC concentrations. found that despite major differences phytoplankton biomass (unimodal distributions, especially fertilization), no were detectable. Instead, ratios high, at intermediate after fertilization, implying low trophic transfer efficiencies. An explanation for the observed resource use, responses zooplankton, was dominance of colony forming chlorophytes reduced edibility DOC, combined mineral (enhanced fertilization. however, increased ratios, largest impact where benefitted light sufficiently cause enhanced N:P. Our results suggest although enrichment do not necessarily increase bottom-up effects may still through promotion species altered quality.