The pigment composition of Phaeocystis antarctica ( Haptophyceae) under various conditions of light, temperature, salinity, and iron

• Published in: Journal of Phycology
• Main Authors: van Leeuwe, Maria A., Visser, Ronald J.W., Stefels, Jacqueline
• Other Authors: Raven, J., Netherlands Organisation for Scientific Research (NWO)
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2014
• Subjects: Antarc*; Antarctica
• Online Access: http://dx.doi.org/10.1111/jpy.12238; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fjpy.12238; https://onlinelibrary.wiley.com/doi/pdf/10.1111/jpy.12238

The pigment composition of P haeocystis antarctica was monitored under various conditions of light, temperature, salinity, and iron. 19′‐ H exanoyloxyfucoxanthin ( H ex‐fuco) always constituted the major light‐harvesting pigment, with remarkably stable ratios of H ex‐fuco‐to‐chl a under the various environmental conditions. Increased pigment‐to‐chl a ratios at low irradiance confirmed the light‐harvesting function of F ucoxanthin ( F uco), 19′‐ H exanoyloxy‐4‐ketofucoxanthin ( H ex‐kfuco), 19′‐butanoyloxyfucoxanthin ( B ut‐fuco), and chl c2 and c3 . Increased pigment‐to‐chl a ratios at high irradiance, low iron concentrations, and to a lesser extent at high salinity confirmed the photoprotective function of diadinoxanthin, diatoxanthin, and ß,ß‐carotene. Pigment ratios were not always according to expectations. The consistent increase in But‐fuco/chl at high temperature, high salinity, and low iron suggests a role in photoprotection rather than in light harvesting. Low H ex‐kfuco/chl ratios at high salinity were consistent with a role as light harvester, but the high ratios at high temperature were not, leaving the function of H ex‐kfuco enigmatic. Dedicated experiments were performed to test whether or not the light‐harvesting pigment F uco could be converted into its structural relative H ex‐fuco, and vice versa, in response to exposure to light shifts. Rapid conversions could not be confirmed, but long‐term conversions cannot be excluded. New pigment ratios are proposed for chemotaxonomic applications. The ratios will improve pigment‐based diagnosis of algal species in waters dominated by P . antarctica .