Fig. 2.

Heat production compared to surface area of eight protist species measured by microcalorimetry. Heat production measured by microcalorimetry, normalized to cell number, and plotted against surface area (μm²), for the marine phototrophic protists (from left to right) Micromonas pusilla (chlorophyte) (n = 2), Thalassiosira pseudonana (diatom) (n = 1), Geminigera cryophila (cryptomonad) (n = 2), Myrionecta rubra (ciliate) (n = 3), Coscinodiscus sp. (diatom) (n = 2), Akashiwo sanguinea (dinoflagellate) (n = 2), Coscinodiscus wailesii (diatom) (n = 2), and Pyrocystis noctiluca (dinoflagellate) (n = 2). A linear regression was performed, yielding a slope of 1.057 (r² 0.9594).