An evaluation of the application of CHEMTAX to Antarctic coastal pigment data

Presented is an evaluation of the application of CHEMTAX (CHEMical TAXonomy) to Antarctic coastal pigments collected along the western Antarctic Peninsula (wAP). Overall analytical error is <20% for all pigments involved in the analysis. CHEMTAX was stable within a range of input pigment ratios; data were analyzed in three bins based on light depths, with each year's data run independently. Results were validated by comparison to those from CHEMTAX methods that included randomized error, feedback loops and additional diagnostic pigments. Blooms during mid-summer (chlorophyll a concentrations >5 μg L−1) were dominated primarily by either diatoms or cryptomonads. Mixed flagellates can also be abundant and Pheaocystis spp. and prasinophytes are frequently present in low concentrations. Comparison with microscopy shows CHEMTAX to give superior results in identifying Pheaocystis spp. with favorable results for other groups. This analysis shows CHEMTAX to be a reliable and stable tool for providing estimations of the main phytoplankton taxa in wAP waters based on long-term data collected during a 12-year time series.

Research highlights
► Study was an evaluation of application of CHEMTAX to Antarctic coastal pigments.
► CHEMTAX found to be a reliable and stable tool for estimating phytoplankton taxa.
► Results were validated by comparison to those from various other CHEMTAX methods.
► We demonstrate that CHEMTAX was stable within a range of input pigment ratios.
► Data were analyzed in 3 light depth bins with each year's data run independently.