Article

Origins of life and evolution of the biosphere

, Volume 33, Issue 4, pp 515-557

Dark Dune Spots: Possible Biomarkers on Mars?

  • Tibor GántiAffiliated withCollegium Budapest (Institute for Advanced Study)
  • , András HorváthAffiliated withBudapest Planetarium of Society for Dissemination of Scientific KnowledgeKonkoly Observatory
  • , Szaniszló BércziAffiliated withEötvös University
  • , Albert GesztesiAffiliated withBudapest Planetarium of Society for Dissemination of Scientific Knowledge
  • , Eörs SzathmáryAffiliated withCollegium Budapest (Institute for Advanced Study)Eötvös University Email author 

Rent the article at a discount

Rent now

* Final gross prices may vary according to local VAT.

Get Access

Abstract

Dark Dune Spots (DDSs) are transitional geomorphologic formations in the frost-covered polar regions of Mars. Our analysis of the transformations and arrangements of subsequent stages of DDSs into time sequence revealed their: (i) hole-like characteristics,(ii) development and formation from the bottom of the frosted layer till the disapperance of the latter, (iii) repeated (seasonal and annual) appearance in a pattern of multiple DDSs on the surface, and (iv) probable origin. We focused our studies on a model in which DDSs were interpreted as objects triggered by biological activity involvedin the frosting and melting processes. We discuss two competing interpretations of DDSs: development by defrosting alone, and by defrosting and melting enhanced by the activity of Martian Surface Organisms (MSOs). MSOs are hypothetical Martian photosynthetic surface organisms thought to absorb sunlight. As a result they warm up by late winter and melt the ice around them, whereby their growth and reproduction become possible. The ice cover above the liquid water lens harbouring the MSOs provides excellent heat and UV insulation, preventsfast evaporation, and sustains basic living conditions until the ice cover exists. When the frost cover disappears MSOs go to a dormant, desiccated state. We propose further studies to be carried out by orbiters and landers travelling to Mars and by analysis of partial analogues on earth.

astrobiology Dark Dune Spots (DDSs) frosting-defrosting geomorphologic analysis of DDSs life on Mars Mars Global Surveyor Mars Odyssey Martian Surface Organisms (MSOs) Southern Polar Region of Mars water ice and liquid water on Mars