Cyanobacteria in salt flat footprint in Death Valley (hardcore astrobiology explanation)
Death Valley is chock full of life, if you know where to look for it. Beneath the white salt layer is a verdant carpet of cyanobacteria. The image shows a closeup of a footprint in a white salt pan in Death Valley near Cottonball Basin. A few of the chunks and broken bits of salt show the layered structure of the salt pan. On the top is a thin bright white crystallized salt layer - most likely a mixture of gypsum (CaSO4 * 2H2O), thenardite (Na2SO4), and some mixed carbonates (Douglas and Yang, 2002). Just below that is a layer brownish-orange layer of cyanobacteria, and below that is a thicker layer of dark green cyanobacteria. Below that is a layer of lighter-colored material likely containing purple anoxygenic phototrophic bacteria (Douglas, 2004).
The boundary between the dark green cyanobacteria and the lower purple bacteria layer is the boundary where oxygenaed (aerobic) and non-oxygenated (anaerobic) environments meet. Previous studies have shown that the cyanobacteria are taking gypsum and converting it into elemental sulfur (rosickyite, a less-stable crystal form of elemental sulfur) (Douglas and Yang, 2002).
If it wasn't for the salt-layer and the orange cyanobacteria layer, we would see a deep green layer of life across the salt plain of Death Valley.
By studying extreme environments and their chemical signatures such as these, we can begin to understand where and how to look for life on other planets.
References:
Douglas, S., 2004. Microbial signatures in evaporite deposits: Evidence from Death Valley, CA. Planetary and Space Science 52, 223-227. doi: 10.1016/j.psss.2003.08.005.
Douglas, S., Yang, H., 2002. Mineral biosignatures in evaporites: Presence of rosickyite in an endoevaporitic microbial community from Death Valley, CA. Geology 30, 1075-1078. doi: 10.1130/0091-7613(2002)0302.0.CO;2.
Cyanobacteria in salt flat footprint in Death Valley (hardcore astrobiology explanation)
Death Valley is chock full of life, if you know where to look for it. Beneath the white salt layer is a verdant carpet of cyanobacteria. The image shows a closeup of a footprint in a white salt pan in Death Valley near Cottonball Basin. A few of the chunks and broken bits of salt show the layered structure of the salt pan. On the top is a thin bright white crystallized salt layer - most likely a mixture of gypsum (CaSO4 * 2H2O), thenardite (Na2SO4), and some mixed carbonates (Douglas and Yang, 2002). Just below that is a layer brownish-orange layer of cyanobacteria, and below that is a thicker layer of dark green cyanobacteria. Below that is a layer of lighter-colored material likely containing purple anoxygenic phototrophic bacteria (Douglas, 2004).
The boundary between the dark green cyanobacteria and the lower purple bacteria layer is the boundary where oxygenaed (aerobic) and non-oxygenated (anaerobic) environments meet. Previous studies have shown that the cyanobacteria are taking gypsum and converting it into elemental sulfur (rosickyite, a less-stable crystal form of elemental sulfur) (Douglas and Yang, 2002).
If it wasn't for the salt-layer and the orange cyanobacteria layer, we would see a deep green layer of life across the salt plain of Death Valley.
By studying extreme environments and their chemical signatures such as these, we can begin to understand where and how to look for life on other planets.
References:
Douglas, S., 2004. Microbial signatures in evaporite deposits: Evidence from Death Valley, CA. Planetary and Space Science 52, 223-227. doi: 10.1016/j.psss.2003.08.005.
Douglas, S., Yang, H., 2002. Mineral biosignatures in evaporites: Presence of rosickyite in an endoevaporitic microbial community from Death Valley, CA. Geology 30, 1075-1078. doi: 10.1130/0091-7613(2002)0302.0.CO;2.