Summary: | Progress Code: onGoing Statement: There are two columns of data for integrated chlorophyll a and they differ. The first integration (column title: Chlorophyll a integrated using 6 sample depths) was based on the 6 depths that were sampled for HPLC pigments. As only 6 points were used for the column-integration the resolution was low. The second integration (column title: Chlorophyll a integrated calibrated fluorometer - high resolution 1 m bins) was based on high resolution fluorescence profiles from the CTD. To calibrate the fluorometer, HPLC chlorophyll a concentrations were compared against fluorescence measurements from the same depths, and a linear regression established (fluorescence = 3.8633 * Chl a – 0.2033, R2 = 0.91). This integration is more accurate given that fluorometer measurements were taken at 1 m intervals throughout the water column, providing high resolution. Purpose This dataset provides the distribution and abundance of phytoplankton taxa throughout the survey region, as determined through analysis of pigment signatures. It also provides integrated chlorophyll a measurements. The aims were to elucidate the drivers that influence phytoplankton populations, and to examine phytoplankton-krill relationships. Pigments samples (1 L) were taken from Niskin bottles, filtered onto 13 mm GF/F filters in a darkened laboratory, then the filters placed in liquid nitrogen for later analysis. Six depths were sampled at each station and always included the near-surface (5-10 m) and the depth of the deep chlorophyll maximum (DCM), as determined using real-time fluorescence data during downward CTD casts. In total 51 stations were sampled. Pigments were later analysed ashore using high performance liquid chromatography (HPLC) according to the method of Wright et al. (2010). Chemotaxonomic analysis was undertaken using the software program CHEMTAX (Mackey et al. 1996; Wright et al. 1996) with 7 phytoplankton taxa chosen for analysis based on previous experience (Wright and van den Enden 2000; Wright et ...
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