Effect of vertical mixing on short-term mycosporine-like amino acid synthesis in the Antarctic diatom, Thalasiossira sp.

Scientia Marina

Marcelo Pablo Hernando¹  Gustavo Adolfo Ferreyra²  Jose Ignacio Carreto³  Mario Carignan³ 

[1] Facultad de Medicina, Universidad de Morón;Institut de Sciences de la Mer de Rimouski;Instituto Nacional de Investigación y Desarrollo Pesquero;

关键词: mycosporine-like amino acids;    vertical mixing;    antarctic diatom;    photoadaptive response;    uv;   

DOI  :  10.3989/scimar.03203.16D

来源: DOAJ

【 摘 要 】

One of the adaptations whereby phytoplankton can alleviate damage induced by ultraviolet radiation (280-400nm) is the synthesis of mycosporine-like amino acids (MAAs). The synthesis of MAAs was studied after exposure of the Antarctic diatom Thalassiosira sp. isolated from Potter Cove (South Shetland Is., Antarctica) to 2 treatments with a solarsimulator: surface (Sfix) and vertical mixing (Mix) irradiance conditions. Light exposure was simulated in daily cycleswith maximum irradiance at noon. Only 2 MAAs, Porphyra-334 (82-85%) and Shinorine (15-18%), were identified. Theconcentration of the two compounds increased during experimental light exposure (50-55%) and declined in the dark (10-15%). During the light period the synthesis rate of MAAs per unit of chlorophyll a was higher in the Sfix treatment (µ=0.17h-1) than in the Mix treatment (µ=0.05 h-1). In spite of the higher MAA levels, low cell numbers were observed in the Sfix treatment, suggesting that the algae synthesized photoprotective compounds at the expense of growth. Our results documentoverlapping effects of both daily light cycles and vertical mixing affecting the synthesis of MAAs. This, and the high thermaldissipation of the ultraviolet B radiation energy (280-320 nm) absorbed by these substances, suggest a rapid photoadaptive response of Thalasiossira sp. upon exposure to elevated irradiance in a stratified water column, as well as the complementary role of vertical mixing in photo-protection.

【 授权许可】

Unknown