HPLC pigment database from the Blanes Bay Microbial Observatory (BBMO), NW Mediterranean (2000–2014)

Sampling was conducted over a period of 14 yr (2000 to 2014) at the Blanes Bay Microbial Observatory (BBMO) station, located in the Bay of Blanes, in the Northwestern Mediterranean Coast (Fig. 1), approximately 60 km north of Barcelona. The BBMO station is a shallow site (~20 m depth) approximately 800 m offshore from the town of Blanes (41° 40' N, 2° 48' E). A total of 162 surface water samples were considered for analysis. The first one was taken in September 2000; from 2001 to 2014, samples were in general collected monthly, with some exceptions. A volume of water varying from 0.7 l to 1 l (depending on the sampling season) was filtered onto Whatman GF/F (nominal pore size 0.7 μm; 25 mm diameter) glass fiber filters with low vacuum (0.4 bars) to prevent cells from breaking. Subsequently, the filters were folded, dried, wrapped in aluminum foil and stored frozen at −80°C until analysis. For pigment extraction, the filters were placed in tubes with 2.5 ml of 90% acetone submerged in ice, and the pigments were extracted by sonication for 30 s. Subsequently, the filters were stored at −20°C. After 24 h, the samples were vortexed and filtered through Whatman GF/F glass fiber filters. Prior to 2008, the samples were analyzed at the Institut de Ciències del Mar (CSIC) in Barcelona according to the method of Zapata et al. (2000), using a ThermoQuest chromatograph (hereafter System 1), which included a P2000 solvent module, an A/S 3000 autosampler, a UV-3000 absorbance detector (440 nm), a FL2000 fluorescence detector (excitation = 430 nm, emission = 662 nm), and an SN 4000 controller. After 2008, analyses were carried out at the Centro Oceanográfico de Gijón/Xixón (IEO-CSIC) following the procedure (hereafter System 2) of Latasa (2014), which increased the sensitivity and lowered the detection limit, using an Agilent series 1200 chromatographic system consisting of a G1311A quaternary pump, a G1367C autosampler with a 100 μl capillary loop, a G1316B column thermostat, and a G1315C diode array detector. A significant change added to the System 2 analyses was the use of trans-β-apo-8'-carotenal, as an internal standard, dissolved in the acetone used for sample extraction. In total, 28 pigments were detected at 440 and 665 nm (System 1) or 474 and 664 nm (System 2) and identified by retention time and online diode array detector.