Dataset: Grazing experiment 2 and 3: CN data
Deployment: Lab_Olson_B

The phytoplankton Emiliania huxleyi CCMP 2668 was grown semi-continuously in atmosphere controlled chambers at three different CO2 treatment concentrations; Ambient (400ppmv), Moderate (750ppmv), and High (1000ppmv).  Cultures were diluted daily starting day 4 with pre-equilibrated media containing f/50 nutrients. 

Expt. 2: On day 8, after ~ 16 generations, 200 mls of E. huxleyi cells from each of the treatment replicates was divided in to two 100 ml samples which were each filtered onto 20mm muffled glass fiber filters (GFF).

Expt. 3: On day 10, after ~ 20 generations, 200 mls of E. huxleyi cells from each of the treatment replicates was divided in to two 100 ml samples which were each filtered onto 20mm muffled glass fiber filters (GFF).

During this sampling, 5 mls of each treatment was fixed in alkaline Lugol’s for counting cells.  One filter was used for TPC (total particulate carbon) and placed in a tin capsule the other was used for TOC and placed in a silver capsule.  All samples were dried for 24 hours at 60°C.  The tin capsules and filters were then folded and held in a desiccator until analysis.  The silver capsules and filters were fumed in a closed container with concentrated sulfuric acid for 24 hours to remove the PIC contained in E. huxleyi’s coccoliths.  The silver capsules and filters were then dried again at 60°C for 24 hrs, folded, and put in a tin capsule which was folded, then they were held in a desiccator until analysis.  For analysis, folded capsules were combusted in a CE Elantech Flash EA 1112 elemental analyzer.  Standard curves were made using known weights of Acetanilide wrapped in tin capsules. Media blanks, filter blanks and capsule blanks were included as controls for background signals.  Cells were counted with a Hemocytometer or gridded Sedgewick Rafter Chamber, depending on cell density.