Photoprotective responses of three intertidal Antarctic macroalgae to short-term temperature stress

• Published in: Frontiers in Marine Science
• Main Authors: Claudio A. Sáez, Macarena Troncoso, Camilo Navarrete, Fernanda Rodríguez-Rojas, Nelso Navarro, Andrés Trabal, Céline Lavergne, Diego Pardo, Murray T. Brown, Iván Gómez, Félix L. Figueroa, Paula S. M. Celis-Plá
• Format: Article in Journal/Newspaper
• Language: English
• Published: Frontiers Media S.A. 2023
• Subjects: Antarctic seaweeds; photoprotective responses; carotenoids; phenolic compounds; mycosporine-like amino acids; Science; Q; General. Including nature conservation; geographical distribution; QH1-199.5; Antarc*; Antarctic; Antarctic Peninsula; Antarctica; King George Island
• Online Access: https://doi.org/10.3389/fmars.2023.1223853; https://doaj.org/article/e3d85976b37d4c86b662dc1c78ad405e

The Antarctic Peninsula is experiencing one of the highest warming rates globally. In polar regions, macroalgae thrive under extreme environmental conditions, which could worsen because of future climate change scenarios, including increased ultraviolet exposure, extremely low light availability, and fluctuating temperatures, particularly in the intertidal zones. To investigate the potential role of photoprotective and antioxidant mechanisms in response to future increases in sea surface temperatures caused by climate change, we conducted laboratory experiments using three intertidal macroalgae model species: Adenocystis utricularis (Ochrophyta, Phaeophyceae), Pyropia endiviifolia (Rhodophyta, Bangiophyceae), and Monostroma hariotii (Chlorophyta, Ulvophyceae). These algae were collected in Punta Artigas (King George Island, Antarctica) and acclimated at 2°C for 48 h. They were then assessed in laboratory experiments for up to 5 days under two treatments: (1) control conditions at 2°C and (2) elevated tem.perature conditions at 8°C, representing the most negative increment in SSTs estimated by the end of the 21st century. Carbon, nitrogen, pigments (chlorophylls and carotenoids), mycosporine-like amino acids (MAAs), and phenolic compounds were quantified after 3 and 5 days of exposure. For M. hariotii, elevated temperatures led to an increase in the C/N ratio, total antioxidant capacity, and levels of nitrogen, total carotenoids, chlorophyll-a, pigments (chlorophyll-b and violaxanthin), and phenolic compounds. For A. utricularis, elevated temperatures led to elevated C/N ratio and levels of chlorophyll-a and carotenoids (fucoxanthin and β-carotene). For P. endiviifolia, elevated temperatures resulted in elevated levels of carotenoids (lutein and β-carotene), phenolic compounds, and MAAs (porphyra-334, shinorine, and palythine). Thus, our study suggests that increasing water temperatures due to global warming can enhance the photoprotective abilities of three Antarctic intertidal macroalgae (M. hariotii, A. ...