title: Contrasting effects of rising CO2 on primary production and ecological stoichiometry at different nutrient levels.
abstract: Although rising CO2 concentrations are thought to promote the growth and alter the carbon : nutrient stoichiometry of primary producers, several studies have reported conflicting results. To reconcile these contrasting results, we tested the following hypotheses: rising CO2 levels (1) will increase phytoplankton biomass more at high nutrient loads than at low nutrient loads, but (2) will increase their carbon : nutrient stoichiometry more at low than at high nutrient loads. We formulated a mathematical model to predict dynamic changes in phytoplankton population density, elemental stoichiometry and inorganic carbon chemistry in response to rising CO2 . The model was tested in chemostat experiments with the freshwater cyanobacterium Microcystis aeruginosa. The model predictions and experimental results confirmed the hypotheses. Our findings provide a novel theoretical framework to understand and predict effects of rising CO2 concentrations on primary producers and their nutritional quality as food for herbivores under different nutrient conditions.
authors.affiliation: Department of Aquatic Microbiology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, P.O. Box 94248, 1090 GE, Amsterdam, The Netherlands.
authors.forename: Jolanda M H
authors.initials: JM
authors.lastname: Verspagen
authors.forename: Dedmer B
authors.initials: DB
authors.lastname: Van de Waal
authors.forename: Jan F
authors.initials: JF
authors.lastname: Finke
authors.forename: Petra M
authors.initials: PM
authors.lastname: Visser
authors.forename: Jef
authors.initials: J
authors.lastname: Huisman
mesh_terms: D002245:Carbon Dioxide / Q000378:metabolism*; D017753:Ecosystem; D046931:Microcystis / Q000502:physiology*; D008954:Models, Biological; D009747:Nutritional Physiological Phenomena; D011156:Population Density; D011157:Population Dynamics
chemical_list: D002245:Carbon Dioxide
keywords: Carbon dioxide; Microcystis aeruginosa; elemental stoichiometry; eutrophication; global change; harmful algal blooms; lakes; nutrient limitation; ocean acidification