Dataset: Fluorometer data (volts) from CTD casts from NOAA Ship R/V Nancy Foster cruises NF1704 and NF1802 in the Gulf of Mexico, May 2017 and 2018

Samples for HPLC chlorophyll were collected pre-dawn from Niskin bottles mounted on a 24-place rosette system equipped with a Seabird SBE911 CTD and a Seapoint fluorometer.  Seapoint fluorometer data (volts) for chlorophyll a is compared with discrete HPLC bottle data.

HPLC samples (2.2-L) were collected for pigment analyses by high-pressure liquid chromatography (HPLC) at the Horn Point Analytical Services Laboratory (University of Maryland Center for Environmental Science).  Pigment samples (2.2-L) were filtered onto GF/F filters, frozen in LN2 and stored at -85°C until extracted, and analyzed using an automated 1100 HPLC system with Agilent temperature-controlled autosampler, Peltier temperature-controlled column oven compartment, PDA detector and ChemStation software.  The HPLC method uses a C8 column and a reversed phase, methanol-based solvent system (Van Heukelem and Thomas, 2001; Hooker et al., 2012).  MVCHLa and DVCHLa are detected at 665 nm.  Carotenoid and xanthophyll accessory pigments are detected at 450 nm.