1. Snow algae and their relevance to astrobiology
Jana Kvíderová
Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic
&
Institute of Botany, Academy of Sciences of the Czech Republic, Třeboň, Czech Republic

2. Snow algae Algae growing in melting snow
„Watermelon snow“ = dense communities of snow algae
Alpine and polar regions
Temporary and perrenial snowfields
Red (left) and green (right) snow. Krkonoše Mts. Czech Republic.

3. Snow algae glaciers and snowfields
Dust- and soil-covered snowfields in Svalbard

4. Snow algae Unicellular or filamentous microorganisms
Chlamydomonas sp.
Chloromonas sp.
Raphidonema nivale…
Complex life cycles
Motile (flagellates) and non-motile (cysts) stages
Chlamydomonas sp. and Chloromonas sp. B C E D
Examples of snow algae species and genera:
A - Chlamynomonas nivalis
B - Chloromonas nivalis
C - Chloromonas brevispina
D - Chloromonas rosae
E - Cryocystis sp.

5. Life cycles
Modified from Hoham et Duval (2001) in Snow ecology

6. Svalbard snow algae
The species and genera of snow algae found in Petuniabukta samples (Kvíderová (2012) Czech Polar Reports). The number indicates the size of the scale in µm
A-F – zygospores of Chlamydomonas cf. nivalis,
G – newly formed zygospore of cf. Chloromonas nivalis,
H-I – cf. Cryodactylon glaciale (? Chlamydomonas brevispina),
J-K – zygospores of Chlamydomonas sp.,
L – cf. Chlainomonas sp.

7. Environment of snow algae I.
Low stable temperature
Freeze-thaw cycles
High and variable radiation (VIS and UV)
Variability of environmental conditions in snow (Kvíderová (2010) Arct Antarct Alp Res)
Abbreviations: PAR - photosynthetically active radiation; Tair - air temperature; Tsnow - snow temperature; UVR - UV radiation

8. Environment of snow algae II.
Variable nutrient availability
Short vegetation period
Snow nutrient concentrations and their relations to occurence of snow algae (Kvíderová et Kociánová (2011) Opera Corcontica)
Abbreviations: Alk - alkalinity; Alt - altitude; Cond - conductivity; DRP - dissolved reactive phosphorus; NH4-N - ammonium nitrogen; NO3-N - nitrate nitrogen; N:Pin - inorganic N:P molar ratio; N:Ptot - total N:P molar ratio; Ntotal - total nitrogen; pH - snow pH; Ptotal - total phosphorus. CbreC - cysts of Chlr. brevispina; CnivC - cysts of Chlr. nivalis; CnivZ - zoospores of Chlr. nivalis; CrosC - cysts of Chlr. rosae.

9. Ecophysiological requirements I.
Temperature and irradiance growth requirements of Chlamydomonas sp. strain Ľadové originating from the High Tatra Mts., Slovakia

10. Ecophysiological requirements II.
Growth of Chlamydomonas sp. strain Ľadové in gradient of temperature (left) and irradiance (right)
Psychrophilic and psychrotolerant species
Tolerance of broad irradiance range