The samples were collected using a CTD rosette and an appropriate volume of water was filtered through a 25mm GF/F filter soon after collection. The filters were then stored in liquid nitrogen until analyzed. The analysis and duplicate filter precision details as well as calibration details are provided in may18atl_HPLC_readme.pdf. The samples were run at NASA GSFC by Crystal Thomas.
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The diagnostic pigments were measured using High-performance liquid chromatography as detailed in Van Heukelem and Thomas (2001) and Hooker et al (2005).
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The HPLC used for pigment analysis is an Agilent RR1200 with a programmable autoinjector (900 ul syringe head), refrigerated autosampler, degasser, and photo-diode array detector with deuterium and tungsten lamps. The HPLC is controlled by Agilent Chemstation software. The 4.6 x 150 mm HPLC Eclipse XDB column (Agilent Technologies, Palo Alto, CA) is filled with a C8 stationary phase (3.5 um stationary phase); the mobile phase consists of a linear gradient from 5-95% solvent B over the 27 minutes, for which solvent A is 70 parts methanol, 30 parts 28 mM tetrabutylammononium acetate (pH 6.5) and solvent B is methanol. The column temperature is 60 C and the photo diode array detector is set to plot chromatograms at 450, 665, and 222 nm to acquire visible absorbance spectra between 350 and 750 nm.
Data notes:\u00a0
\nmissing = -9999
\nbelow detection limit = -8888
\nabove detection limit = -7777
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BCO-DMO Processing:
\n- replaced hyphens with underscores in parameter names;
\n- lat and lon labels were backwards in original file; switched them around (determined by looking at boudning box of EN614 cruise)
\n- created ISO_DateTime_UTC field from original date/time columns