Heterotrophic and autotrophic particle (cell) abundance in water column. Heterotrophic and autotrophic particle (cell) abundance in water column. Small (0.2- to 1.999-μm equivalent spherical diameter [ESD]) (A) and large (2- to 60-μm ESD) (C) particle size distribution in high (solid lines)- and low (dashed lines)-organic-nutrient-enriched mesocosms, and mean ± SE total particle abundance (n = 3) of small (B) and large (D) particle sizes in water of low- and high-nutrient treatments on day 0. Dagne Duguma et al. mSphere 2017; doi:10.1128/mSphere.00387-16