Dataset: Cell abundance, forward scatter, chlorophyll, growth rate, and FvFm.0 measurements from reciprocal transplant assays

Six lineages of each of two strains of the genus Ochromonas (CCMP1393, and CCMP2951) have been evolving at three temperatures, the ancestral temperature of 24C, and cooler and warmer temperatures of 18C and 30C. A third strain, CCMP 1391 does not survive at 30C and is only evolving at 18C and 24C. The experiment is run at two light levels, 100uE and 50uE. Cultures are maintained in batch culture in K medium made by adding pre‐mixed nutrients (ordered from the NCMA) to 0.2 μm filtered Santa Barbara coastal seawater in three light- and temperature-controlled incubators.

Evolving lineages are 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 are conducted every three months. This involved placing subsamples of each evolving lineage into all three temperatures, and comparing their performance in characteristic tests (growth rate, photosynthetic efficiency etc.).

Sampling and analytical procedures:

Guava count:
Cell density and relative size are measured every day for a 4-day growth period using a Guava easyCyte Flow Cytometer (Luminex Corporation, Austin, TX).

Chlorophyll Extractions:
Cellular chlorophyll-a (chl-a) content is measured by filtering cells onto a 25mm-diameter GF/F filter (Whatman) and extracting for 24 hours in a 90% acetone solution. Chl-a concentration in the acetone solution is read using a Trilogy fluorometer (Turner Designs, San Jose, CA).

FIRe Dark-acclimated Fv/Fm measurement:
Photosynthetic efficiency is measured using a mini Fluorescence Induction and Relaxation (FIRe) system (custom built by M. Gorbunov, Rutgers University).

Known Issues/Problems:
There was no chlorophyll collected during the first three backtransfers. Some FvFm data is missing because the FIRe was unable to process the data.