Nutrient deposition and ecosystem function over spatial gradients

Brazil picHuman activities have increased the atmospheric deposition of nitrogen (N) and phosphorus (P) into the biosphere 1- to 4-fold over ambient levels. Future inputs are forecast to increase and will probably shift primary producers from N-limitation to P-limitation, particularly in aquatic ecosystems. Tank-bromeliads and pitcher plants are model systems for studying the impacts of nutrient deposition on an entire ecosystem, because we can easily manipulate nutrient inputs in realistic field experiments, and measure nutrient pools and fluxes on time scales of days, weeks and months. We will systematically combine large-scale survey data with field manipulations to determine the consequences of increased N and P deposition into whole ecosystems.