Dataset: Retinoid data from Niskin bottle samples from B/O Sarmiento de Gamboa cruise Hotmix2014 in the Mediterranean in 2014 (Marine Retinoids project)

Size Fractionation of retinal, bacteriochlorophyll and chlorophyll:
Samples for quantification of light harvesting pigments in eukaryotes and prokaryotes were collected at a number of depths within the euphotic zone (see field study sites). Seawater were collected from each CTD depth using Niskin bottles and immediately filtered. Size fractionated samples were collected using a series of in-line filters using a peristaltic pump (flow rate < 50 ml per minute). Filters of different pore-size (0.2 um for picoplankton, and 3.0 um for nanoplankton) were used for the fractionation. Particulate samples were immediately stored at -80 degrees C until analysis. For analysis, samples were extracted with methanol (retinal, chla, and Bchl) and with hydroxylamine (oxime) and analyzed by liquid chromatography/tandem mass spectrometry (LC/MS/MS). The LCMS system consists of a ThermoTSQ Quantum Access electro-spray ionization triple quadrupole mass spectrometer, coupled to a Thermo Accela High Speed Liquid Chromatography system (Seegers et al., in preparation). The mobile phase conditions for the LCMS method for chlorophyll and bacteriochlorophyll analyses were adapted from Goericke (2002). All retinoid samples were analyzed in triplicate using an external calibration curve, though not presented, precision was typically in the 5-15% range.