Relationships between pigment ratios and growth irradiance in 11 marine phytoplankton species

Abstract

Light-dependent variation in pigment content was examined in 11 marine phytoplankton species representing 8 algal classes. Batch cultures of each species were acclimated to 7 irradiances between 10 and 700 µmol photons m -2 s -1. High-performance liquid chromatography analysis on exponentially growing cultures revealed that pigment ratios normalised to chlorophyll a (chl a) generally fell within the ranges previously reported for species of the same taxa. Unambiguous lightharvesting pigments (e.g. chlorophylls, fucoxanthin) showed limited amplitude of variation between low and high light conditions, while those involved in photoprotection (e.g. zeaxanthin, lutein, alloxanthin, diatoxanthin) dramatically increased under high light. Most of the relationships between pigment:chl a ratios and growth irradiance were quite well described using simple linear models. Among pigments shared by several species, chl b and c 3 , fucoxanthin, zeaxanthin, lutein, diadinoxanthin and diatoxanthin exhibited similar trends regardless of the species studied, allowing general equations to be determined for each of these pigments. Determination of light:pigment relationships is a prerequisite for the development of more advanced modeling techniques such as artificial neural networks in chemotaxonomic studies. KEY WORDS: Phytoplankton · Cultures · Pigment ratios · Irradiance · Regression analysis · HPLC Resale or republication not permitted without written consent of the publisherMar Ecol Prog Ser 425: [63][64][65][66][67][68][69][70][71][72][73][74][75][76][77] 2011 phytoplankton ecology at various temporal and spatial scales (Simon et al. 2009). An unsuspected diversity has been revealed, in particular in the picoplanktonic size fraction, even sometimes at the intraspecific level (e.g. Rodriguez et al. 2005, Liu et al. 2009).The chemotaxonomic approach relies on the quantitative measurement of total chlorophyll a (Tchl a) as a proxy of phytoplankton biomass and of accessory pigments (other chlorophylls, carotenoids) as more or less specific chemotaxonomic markers. The contributions of distinct groups of microalgae to Tchl a can then be inferred from accessory pigment to Tchl a ratios (Jeffrey et al. 1999). A limited number of pigments can be assigned unambiguously to an algal class (e.g. alloxanthin for Cryptophyceae, but see Lewin et al. 2000) or exceptionally to a genus (i.e. divinyl-chl a for Procholorococcus, which in field studies is also included in Tchl a estimates). On the other hand, some pigments are distributed across several classes (e.g. fucoxanthin in Bacillariophyceae, Chrysophyceae, Dinophyceae and Prymnesiophyceae) or shared by groups of species without correspondence with conventional taxa (e.g. 19'hexanoylfucoxanthin in some Haptophyceae and Dinophyceae) (Jeffrey & Vesk 1997). Along with this qualitative variability, it is well documented that pigment concentrations can also change with the physiological state of the cells, thereby explaining quantitative intraclass differences between species as well...

HPLC pigment profiles of 31 harmful algal bloom species isolated from the coastal sea areas of China

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Strategy of photo-protection in phytoplankton assemblages in the Kongsfjorden, Svalbard, Arctic

“…Xanthophyll pigments, such as DD and DT, are present in Prymnesiophyceae, Dinophyceae and Bacillariophyceae (Silva et al, 2007;Laviale and Neveux, 2011), and are thought to infl uence the spatial distribution of these organisms, as does the WSC in the inner bay. The Cryptophyte Rhodomonas baltica does not produce DT or DD but is known to utilize alloxanthin as a xanthophyll pigment (Laviale and Neveux, 2011).…”

Hyperspectral optical discrimination of phytoplankton community structure in Funka Bay and its implications for ocean color remote sensing of diatoms

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