Ecophysiology of Chloromonas hindakii sp. nov. (Chlorophyceae), Causing Orange Snow Blooms at Different Light Conditions

Abstract

Slowly melting snowfields in mountain and polar regions are habitats of snow algae. Orange blooms were sampled in three European mountain ranges. The cysts within the blooms morphologically resembled those of Chloromonas nivalis (Chlorophyceae). Molecular and morphological traits of field and cultured material showed that they represent a new species, Chloromonas hindakii sp. nov. The performance of photosystem II was evaluated by fluorometry. For the first time for a snow alga, cyst stages collected in a wide altitudinal gradient and the laboratory strain were compared. The results showed that cysts were well adapted to medium and high irradiance. Cysts from high light conditions became photoinhibited at three times higher irradiances (600 µmol photons m−2 s−1) than those from low light conditions, or likewise compared to cultured flagellates. Therefore, the physiologic light preferences reflected the conditions in the original habitat. A high content of polyunsaturated fatty acids (about 60% of total lipids) and the accumulation of the carotenoid astaxanthin was observed. They are regarded as adaptations to cope with extreme environmental conditions of snow that include low temperatures, freeze-thaw cycles, and variable light intensity. The intraspecific ability of adaptation of the photosynthetic apparatus to different irradiance regimes seems to be advantageous for thriving in different snow habitats.

Snow and Glacial Algae: A Review1

“…The snow alga, Chloromonas hindakii , was found in orange snow in three European mountains ranges, Krkonoše and Jesenίky (Czech Republic) and High Tatras (Poland and Slovakia; Procházková et al. 2019b). Using 18S rDNA, rbc L, and ITS2 rDNA phylogenetic analyses and morphological traits from field and cultured material, Cr.…”

“…Cysts of the snow alga, Chloromonas hindakii , from mountain ranges in the Czech Republic, Poland, and Slovakia showed high levels of PUFAs (65.8% and 58.1% of total lipids), whereas the content of saturated acids did not exceed 23% (mainly palmitic acid, 16:0; Procházková et al. 2019b). This combination was regarded as an adaptation to cold temperatures.…”

“…hindakii , harvested from high light conditions were photoinhibited at levels above 600 μmol PAR · m −2 · s −1 (Procházková et al. 2019b). This was three times higher than those from low light conditions, indicating photophysiological adaptation mechanisms.…”

Ecophysiological and ultrastructural characterisation of the circumpolar orange snow alga Sanguina aurantia compared to the cosmopolitan red snow alga Sanguina nivaloides (Chlorophyta)

“…To understand the ecophysiological adaptation of these extremophiles to their harsh environment, characteristics such as life cycles, pigment composition, ice-binding proteins, photosynthetic light preferences and fatty acid profiles have been studied (Leya 2013 ). The focus of such studies has been on red snow forming species in high alpine (Remias et al 2005 ) or polar sites (Soto et al 2020 ), or on taxa causing orange snow in mid-latitude mountainous regions (Procházková et al 2019b ). In contrast, data on S. aurantia , which causes orange blooms at (Sub-)Arctic climate, are scarce.…”

Enigmatic Microalgae from Aeroterrestrial and Extreme Habitats in Cosmetics: The Potential of the Untapped Natural Sources

“…and Trentepohlia spp. [53][54][55][56][57][58][59][60][61][62]. In contrast, other typical green snow algae of the genus Raphidonema (Trebouxiophyceae, Chlorophyta) are unable to develop such orange-or red-colored cell types [50,53].…”