Cultures of\u00a0\u00a0Emiliania\u00a0huxleyi\u00a0were obtained from the National Center for Marine Algae and Microbiota at Bigelow Laboratories (all CCMP strains), or from Dr. D. Iglesias-Rodriguez at UC Santa Barbara (strain NEZH) and maintained in the Strom laboratory at Shannon Point Marine Center.
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Batch cultures were grown in 50-100 ml volumes of seawater (salinity = 30) amended with f/50 nutrients, at a temperature of 15 deg C and an irradiance of 140-300 umol photons m-2\u00a0s-1\u00a0on a 12L:12D light cycle. Replicate cultures (n=3) were subsampled for chemical measurements at cell densities of 1.4 to 2.7 x 10^5\u00a0cells ml-1\u00a0(DMSP) and 3.6 to 12.8 x 10^5\u00a0cells ml-1\u00a0(H2O2). Different chemical and size measurements reported for a given strain were made over the course of several separate experiments.
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Dimethylsulfoniopropionate (DMSP) contained within\u00a0E.\u00a0huxleyi\u00a0cells was measured using a Shimadzu GC-14A gas chromatograph and flame photometric detection, following the methods of Wolfe et al. (2002 J.\u00a0Phycol.\u00a038:\u00a0948-960).\u00a0 Cells were captured on 25 mm glass fiber filters (effective pore size 0.7 um) and placed into 3 ml 5N NaOH for hydrolysis.\u00a0Method\u00a0was standardized using ultrapure DMSP-Cl (standard range 0.625 to 50 nM; r2\u00a0\u22650.998).
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Hydrogen peroxide (H2O2) released into the dissolved phase by\u00a0E.\u00a0huxleyi\u00a0was measured using the Amplex Red \u2013 horseradish peroxidase method, using a kit from Molecular Probes (now part of Thermo Fisher Scientific) according to kit directions and to Suggett et al. (2008 J\u00a0Phycol\u00a044:\u00a0948-956).\u00a0Fluorescent\u00a0reaction product was quantified in a BioTek Synergy M plate reader (565 nm excitation, 585 nm emission). True reagent blanks were obtained by catalase treatment of\u00a0E.\u00a0huxleyi\u00a0culture filtrate (50 U ml-1, 45 min, room temperature) following Shaked et al. (2010 Environ Sci Technol\u00a044:\u00a03238-3244). Method was standardized using ultrapure H2O2\u00a0(standard range 0.025 to 0.5 uM; r2\u00a0= 0.98)
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E.\u00a0huxleyi\u00a0cell size was obtained by imaging live cells (n = 23-29) at 1000x magnification on a Leica DM5500 B microscope, and sizing them with associated image analysis software. Calcification (i.e. whether a strain harbored coccoliths) was also confirmed\u00a0during\u00a0microscopy. Note that the sample of strain CCMP3266 used for size measurement comprised a mixture of calcifying and non-calcifying cells.
Cell size and chemical characteristics (H2O2 production, DMSP content) of five strains of coccolithophore Emiliania huxleyi, grown in laboratory culture
BCO-DMO Data Processing Notes:
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-Data compiled into one table from multiple spreadsheets
\n-Replaced all blank cells with \"nd\"