Freezing tolerance and photosynthetic performance of polar seaweeds at low temperatures

• Published in: botm
• Main Authors: Becker, Susanne, Walter, Bettina, Bischof, Kai
• Format: Article in Journal/Newspaper
• Language: English
• Published: Walter de Gruyter GmbH 2009
• Subjects: Plant Science; Aquatic Science; Ecology, Evolution, Behavior and Systematics; Arctic; Antarctic; Antarc*
• Online Access: http://dx.doi.org/10.1515/bot.2009.079; https://www.degruyter.com/document/doi/10.1515/BOT.2009.079/xml; https://www.degruyter.com/document/doi/10.1515/BOT.2009.079/pdf

Abstract Organisms populating benthic shallow water systems of both polar regions are adapted to a particularly harsh environment. We studied effects of freezing and the combination of high light intensities and low water temperatures on photosynthesis of key macroalgal species from the Arctic intertidal ( Fucus distichus ) and Antarctic subtidal ( Palmaria decipiens ). Photosynthetic activity of F. distichus specimens was monitored during the freezing process; there was a marked decrease in quantum yield with decreasing temperatures, and a rapid recovery as soon as temperatures increased again. Thus, under the experimental conditions tested, no indication of photodamage was found. Specimens of Palmaria were exposed to a combination of high light intensities and low water temperatures. A persistent impairment of photosynthetic activity occurred at 0°C at light intensities of 400 μmol photons m -2 s -1 . In all treatments, there was a decreasing ratio of phycobiliproteins to chlorophyll a . Overall, the two studies provide baseline data for interpreting physiological responses of two important macroalgal species in an extreme environment, the polar coastal ecosystem.