Patterns of CO2 concentration and inorganic carbon limitation of phytoplankton biomass in agriculturally eutrophic lakes

• CO 2 undersaturation in eutrophic lakes is more common than previously thought. concentration affected by lake depth, solar irradiance and chlorophyll. A set of criteria for distinguishing carbon- from light-limitation presented. Whole-lake examples carbon-limitation around the world are offered. Lake eutrophication a pervasive problem globally, particularly serious agricultural densely populated areas. Whenever nutrients nitrogen phosphorus do not limit phytoplankton growth directly, high rates will rapidly lead to biomass increases causing self-shading light-limitation, eventually depletion. The paradigm limitation light so pervasively established, that lack nutrient ordinarily interpreted as sufficient evidence condition limitation, without considering possibility inorganic carbon. Here, we firstly evaluated how frequently occurs Pampa plains. Our results confirm conditions develop much (yearly 34%, summer 44%) these agriculturally impacted deep, temperate forested watersheds. Secondly, used Generalized Additive Models fit trends three drivers: total incident irradiance, chlorophyll concentration, depth; eight multi-year datasets Europe, North South America, Asia New Zealand. depletion was often observed at levels, shallow water. also occurred concentration. Finally, identified occurrences light- whole-lake scale. different responses allowed us detecting limitation. For first time, provided carbon biomass. represent two major converging environmental problems have additive contrasting effects, promoting phytoplankton, leading Their interactions deserve further exploration imaginative approaches deal with their effects.