The snow alga Chloromonas kaweckae sp. nov. (Volvocales, Chlorophyta) causes green surface blooms in the high tatras (Slovakia) and tolerates high irradiance

Abstract

Seasonally slowly melting mountain snowfields are populated by extremophilic microalgae. In alpine habitats, high‐light sensitive, green phytoflagellates are usually observed in subsurface layers deeper in the snowpack under dim conditions, while robust orange to reddish cyst stages can be seen exposed on the surface. In this study, uncommon surface green snow was investigated in the High Tatra Mountains (Slovakia). The monospecific community found in the green surface bloom consisted of vegetative Chloromonas cells (Volvocales, Chlorophyta). Molecular data demonstrated that the field sample and the strain isolated and established from the bloom were conspecific, and they represent a new species, Chloromonas kaweckae sp. nov., which is described based on the morphology of the vegetative cells and asexual reproduction and on molecular analyses of the strain. Cells of C. kaweckae accumulated approximately 50% polyunsaturated fatty acids, which is advantageous at low temperatures. In addition, this new species performed active photosynthesis at temperatures close to the freezing point showed a light compensation point of 126 ± 22 μmol photons · m−2 · s−1 and some signs of photoinhibition at irradiances greater than 600 μmol photons · m−2 · s−1. These data indicate that the photosynthetic apparatus of C. kaweckae could be regarded as adapted to relatively high light intensities, otherwise unusual for most flagellate stages of snow algae.

Adaptation versus plastic responses to temperature, light, and nitrate availability in cultured snow algal strains

“…preferentially grew under higher light, which was not apparent for either Microglena sp.. NPQ did not vary between light treatments for Antarctic Chloromonas sp., but was ∼600% ± 200% higher overall as compared to the other three strains (Fig 4E ), suggesting a greater dependence on NPQ processes in this strain. The capacity of another closely related snow alga, Chloromonas kaweckae , to cope with higher light conditions has also been noted in situ , where it has been found in the upper 3 cm of the snowpack (Procházková et al 2023 ).…”

“…As the quantity and quality of PAR available to snow algae is dynamic in both the short and long term, photosystems need to be flexible to utilize light efficiently, alongside preventing excess light from causing cellular damage (Remias et al 2005 , Procházková et al 2023 ). When exposed to a continuous high light, chlorophytes have been shown to downsize the size of their antenna complex after several hours, such that cells still absorb adequate light while protecting PSII from photodamage, with the reverse true for long-term, low light acclimation (Melis 1991 ).…”

Phylogeny and lipid profiles of snow-algae isolated from Norwegian red-snow microbiomes

“…C18:1n-9 has been reported as a dominant fatty acid in many isolated snow algae strains in N-deprived or stationary phase conditions, including Raphidonema and Chloromonas (Spijkerman et al 2012 , Hulatt et al 2017 , Suzuki et al 2019 ), as well as in field samples of red snow composed of Sanguina nivaloides (Procházková et al 2019a ) and other red, orange, or green snow (Bidigare et al 1993 , Spijkerman et al 2012 , Davey et al 2019 ). On the other hand, monospecific snow algae blooms caused by C. kaweckae (green, Procházková et al 2022 ), C. nivalis subsp.tatrae, subsp. (brownish-red, Procházková et al 2018a ), Chloromonas krienitzii (orange, Procházková et al 2020 ), C. hindakii (orange, Procházková et al 2019b ), Chlainomonas sp.…”

Diversity and Distribution of Carotenogenic Algae in Europe: A Review

“…Chloromonas krienitzii was sampled from the snow in the Sarntal Alps, South Tyrol (Italy), High Tatra Mountains (Slovakia, Poland) and from North Pindus (Greece) [ 145 ] ( Table 2 ). Procházková et al [ 160 ] described Chloromonas kaweckae Procházková, Matsuzaki, Řezanka, Nedbalová and Remias in the High Tatras (Slovakia) tolerant to high light intensities. Diversity of Chloromonas was also studied in the Svalbard Archipelago (Norway) [ 73 ] ( Table 2 ).…”

“…Indeed, mountain ranges, such as Alps in Italy and Austria, Sierra Nevada in Spain, High Tatra in Slovakia and Poland, and Giant Mountains in Czechia, Vitosha, Central Balkan Mountains, and Pirin Mountains in Bulgaria. High diversity of snow alpine microalga was recorded there [ 51 , 73 , 86 , 107 , 143 , 144 , 145 , 146 , 147 , 148 , 149 , 151 , 152 , 153 , 154 , 155 , 156 , 157 , 158 , 159 , 160 ]. The same is true for polar snow valleys and mountains of Norway, especially on the Svalbard Archipelago [ 73 , 86 , 120 , 145 , 150 , 161 ].…”