We report here production rates of isoprene and monoterpene compounds (α-pinene, β-pinene, camphene and d-limonene) from six phytoplankton monocultures as a function of irradiance and temperature. Irradiance experiments were carried out for diatom strains (<i>Thalassiosira weissflogii</i> and <i>Thalassiosira pseudonana</i>), prymnesiophyte strains (<i>Pleurochrysis carterae</i>), dinoflagellate strains (<i>Karenia brevis</i> and <i>Prorocentrum minimum</i>), and cryptophyte strains (<i>Rhodomonas salina</i>), while temperature experiments were carried out for diatom strains (<i>Thalassiosira weissflogii</i> and <i>Thalassiosira pseudonana</i>). Phytoplankton species, incubated in a climate-controlled room, were subject to variable light (90 to 900 μmol m<sup>−2</sup> s<sup>−1</sup>) and temperature (18 to 30 °C) regimes. Compared to isoprene, monoterpene emissions were an order of magnitude lower at all light and temperature levels. Emission rates are normalized by cell count and Chlorophyll <i>a</i> (Chl <i>a</i>) content. Diatom strains were the largest emitters, with ~ 2 × 10<sup>−17</sup> g(cell)<sup>−1</sup>h<sup>−1</sup> (~ 35 μg (g Chl <i>a</i>)<sup>−1</sup> h<sup>−1</sup>) for isoprene and ~ 5 × 10<sup>−19</sup> g (cell)<sup>−1</sup> h<sup>−1</sup> (~ 1 μg (g Chl <i>a</i>)<sup>−1</sup>) h<sup>−1</sup>) for α-pinene. The contribution to the total monoterpene production was ~ 70% from α-pinene, ~ 20% for d-limonene, and < 10% for camphene and β-pinene. Phytoplankton species showed a rapid increase in production rates at low irradiance (< 150 μmol m<sup>−2</sup> s<sup>−1</sup>) and a gradual increase at high (> 250 μmol m<sup>−2</sup> s<sup>−1</sup>) irradiance. Measurements revealed different patterns for time-averaged emissions rates over two successive days. On the first day, most of the species showed a distinct increase in production rates within the first 4 h while, on the second day, the emission rates were overall higher, but less variable. The data suggest that enhanced amounts of isoprene and monoterpenes are emitted from phytoplankton as a result of perturbations in environmental conditions that cause imbalance in chloroplasts and force primary producers to acclimate physiologically. This relationship could be a valuable tool for development of dynamic ecosystem modeling approaches for global marine isoprene and monoterpene emissions based on phytoplankton physiological responses to a changing environment.