Dataset: Photosynthesis-Irradiance Curves

Six independent lineages of each Ochromonas strain were grown in batch cultures in three light- and temperature-controlled incubators (18°C, 24°C, and 30°C), and regularly tested for several characteristics including growth rate, cell size, chlorophyll content, and photosynthetic efficiency. To show that characteristic changes are indeed from an evolutionary response as opposed to phenotypic plasticity, reciprocal transplant assays were conducted every three months for two years. This involved placing subsamples of each evolving lineage into all three temperatures, and comparing their performance in characteristic tests (growth rate, photosynthetic efficiency etc.). Evolved lineages performing equally at all "acclimation temperatures" is evidence of plasticity, while differences in performance indicates adaptation. Using growth rate and photosynthetic rate to compute the relative contributions of autotrophy versus heterotrophy for each evolved lineage.

Procedures for Photosynthesis-Irradiance curves:
Dark-acclimate cells to be sampled for at least 15 minutes. This operation requires the actinic light source (ALS). In the DOS prompt Type 'fview'. Press enter. The data acquisition program will open. Adjust the number of samples and PAR steps to 20. Adjust the max PAR to 1001. MTF and MTRP stay set to 0. Adjust the acclimation time between each sample to 15 seconds. Homogenize sample before reading. Insert your test tube with dark-acclimated sample. Press 's' (for 'start/stop'). Adjust the 'Gain:' so that the fluorescence trace is as close to, but not greater than, 100%.

Missing Data:
Occasionally, at high light levels and especially high temperatures, the signal to noise ratio of the fluorescence signal is very low. This causes noisy instrument output, which fails at the analysis (fprope.exe) stage. These data are missing from the dataset, and can be identified when a run (unique combination of week, light level, food level, strain, evolutionary temperature, acclimation temperature, and replicate) has fewer than twenty rows of data.