Fig. 3.

(A–D and F–I) Depth-integrated balance of autotrophic and heterotrophic acquisition of C, N, P, and Fe by nanoplankton in the two-guild (A–D) and mixotrophy (F–I) models. Black dots in G–I indicate sites where in situ nutrient addition experiments have identified (at least occasional) limitation by that nutrient element (30). (E) Global balance of depth-integrated nanophytoplankton and nanozooplankton C biomass in the two-guild model. (J) Relative change between the two models in the molar ratio of photosynthetic C acquisition to the uptake of the most-limiting nutrient (N, P, or Fe; Supporting Information).