Meeting Abstract

P1.154  Friday, Jan. 4  Transcriptomic analysis of the effects of Ocean Acidification and Increased Temperature in the coccolithophore Emiliania huxleyi DORFMAN, R.E.*; LI, D.; BENNER, I.; LEFEBVRE, S.; CARPENTER, E.J.; KOMADA, T.; STILLMAN, J.; San Francisco State University Racheld@mail.sfsu.edu

Calcifying marine phytoplankton (i.e. coccolithophores) play an important role in the global carbon cycle. Global change related shifts in temperature, nutrient composition, and pH via ocean acidification alter the biology of coccolithophores. The world’s most abundant coccolithophore, Emiliania huxleyi, exhibits contrasting physiological responses to increased CO₂, but little is known about the molecular mechanisms involved in the response to increasing CO₂ or temperature. E. huxleyi (Strain CCMP371) was grown in continuous chemostat cultures for over 200 generations at “present” (380 ppm, 20°C) and “future” (800 ppm, 24°C) ocean conditions. Two replicates of each chemostat treatment were run, and n=6 samples were taken from each chemostat (n=24 samples total) after 200 generations. Total RNA was purified from each sample and used for the construction of RNA-seq cDNA libraries, which were sequenced on the Illumina HiSeq2000 platform in order to gain insight into the transcriptome response. For each library we obtained an average of about 50,000,000 sequence reads. When mapped against the E. huxleyi genome and trimmed for quality, these reads corresponded to at least 22,000 genes that were expressed. Over 700 genes were differentially expressed between the two treatments, with the majority of these genes upregulated in present ocean conditions relative to future conditions. Our analysis of the specific cellular pathways that are affected by ocean acidification will provide insight as to how coccolithophores might respond to future environmental change, as well as provide opportunities to target the specific physiological mechanisms involved in the response of these cells to future ocean conditions.