PHOTOSYNTHESIS IN THE SNOW: THE ALGACHLAMYDOMONAS NIVALIS(CHLOROPHYCEAE)¹

Abstract

Red blooms of snow algae consisting almost exclusively of large spherical red cells of Chlamydomonas nivalis (Bauer) Wille are widespread during the summer in the Beartooth Mountains in Montana and Wyoming. Field studies designed to examine the effects of temperature, light, and water potential on algal activity were performed with natural populations using photosynthetic 14C‐HCO3‐ or 14CO2 incorporation as a measure of activity. The algae photo‐synthesized optimally at 5.4 × 104 lx, but were not inhibited by increased light intensity up to 8.6 × 104 lx, the maximum observed in the field. Photosynthesis was sensitive to a reduction in water potential, and since low water potentials develop in snow at temperatures below 0 C, it is unlikely that significant algal activity occurs at the sub‐0 temperatures which occur throughout winter. Photosynthesis was much lower following melting of the snow, but this was probably due to decreased diffusion of CO2. The optimal temperatures varied considerably among the different algal populations. Most samples photo‐synthesized optimally at 10 or 20 C but retained substantial activity at temperatures as low as 0 or ‐3 C. Exceptional samples photosynthesized optimally at 0 or ‐3 C. It is proposed that the varied temperature responses reflect the presence of different temperature strains. Taken together, the data suggest that development of the snow algae can occur only during the summer months.

Surface gas-exchange processes of snow algae

“…C. nivalis is apparently global, as it has been reported from New Zealand (1), Australia (2), and Europe (3)(4)(5)(6). In North America, it occurs in Alaska (5), the Cascade Mountains of the Pacific Northwest (7,8), the Sierra Nevada of California (7,9), and the Rocky Mountains of the western United States and Canada (7,10,11).…”

“…Thomas also reported that subsurface samples, which received less light, photosynthesized more than samples from the surface, suggesting that photoinhibition might have occurred in the surface layers. Mosser et al (10), however, reported no photoinhibition up to 8.5 ϫ 10 4 lux (Ϸ1,600 mol⅐m Ϫ2 ⅐s Ϫ1 ). Mosser et al (10) also studied the effects of temperature on 14 CO 2 uptake, finding that most populations had temperature optima between 10°C and 20°C.…”

Photosynthesis, pigments and ultrastructure of the alpine snow algaChlamydomonas nivalis

“…Earlier studies used different methods ( 14 C incubation or CO 2 gas exchange) and, with one exception (a study of a few green snow species in the former Czechoslovakia, Koma´rek et al, 1973), were carried out on algae from other continents, such as North America (Thomas, 1972;Mosser et al, 1977;Thomas & Duval, 1995;Williams et al, 2003).…”

Clay Aerosols and Arctic Ice Algae

“…Red snow algae have been described from both Antarctica and the arctic (Newton, 1982;Nicholas et al, 1990), North Finland Eurola, 1973, 1974), east Greenland (Fjerdingstad et at., 1974;Koshima, 1991), the Alaskan arctic (Kobayashi, 1967), and Japan (Fukushima, 1963;Kobayashi and Fukushima, 1952). Most of the red snow algae species collected from various regions have been classified and determined as Chlamydomonas nivalis (chlorophyceae; chlorophyta volvocales) (Mosser et al, 1977;Newton, 1982;Fjerdingstad et al, 1974;Kobayashi, 1967). Red blooms of snow algae consisting almost exclusively of large spherical red cells of Chlamydomonas nivalis are widespread only during the summer months.…”