Fatty acid profiles by biovolume of replicate populations of Thalassiosira pseudonana, selected at 16 and 31C for ~500 generations and assayed at 4 temperatures from 2017-12-09 to 2018-01-05 (NCEI Accession 0291927)

Acquisition Description:
Details of the long-term selection experiment can be found in another dataset associated with this project, entitled “Temperature-growth rate curves for Thalassiosira pseudonana ”, and in O’Donnell et al. (2018), Global Change Biology. After ~500 generations of experimental selection (5 replicate populations at 16°C and 5 at 31°C), we acclimated each replicate population for 10 generations at 20°C, then acclimated each at 10, 16, 26 and 31°C for an additional 10 generations. We then sub-cultured each acclimated population into triplicate batch cultures, starting with 100,000 cells in 40 ml of L1 marine culture medium in a 50 ml tissue culture flask. We grew all experimental cultures (2 selection temperatures x 5 replicate populations x 4 assay temperatures x 3 assay replicates = 120 total experimental units) to late log phase, estimating per-capita growth rates by placing each tissue culture flask in a spectrophotometer daily and measuring absorbance at 436 nm. We harvested 15 ml of culture for fatty acid analysis, retaining ~25 µl for enumeration on a CASY particle counter. The remaining volume was used for analyses not addressed here.

Cells were harvested by filtration through a 25mm Whatman GF/B filter. We extracted fatty acids from T. pseudonana cells using a solution of chloroform, methanol, and formic acid (10:20:1). We analyzed fatty acid profiles by performing fatty acid methyl ester (FAME) reactions on each GF/B filter sample (Wang and Benning 2011; adapted for algae by Boyle et al. 2012) and quantifying fatty acids using gas chromatography.