The artist on site. Lago Sarmiento in Southern Chile is one of a handful of sites on Earth where the ancient living-rock thrombolites can be seen.
Today I’ve been “revisiting” a geological wonder I experienced in 2024 on a research trip to the Patagonian region of Chile and Argentina. Thrombolites are globular-looking rock forms made by microbial organisms. The metabolic activity of these organisms, often cyanobacteria, causes calcium carbonate to accumulate into ever-increasing masses of stone. A more famous site to view these unusual creations is in Western Australia at Hamelin Pool, Shark Bay. Here at Lago Sarmiento, there are no signs of people; no boardwalk, buildings, plaques, or vehicles. Just wild, open landscape.
The “bathtub ring” of whitish thrombolites can be seen encircling the lake and indicating past water levels.
Last fall I read a chapter with my book club called (Sym)Poetics of Biomineralisation: Molecular Biology/Literature/Posthuman Poetics by Ruth Alison Clemens and Jennifer Aurelie Crouch. Yes, it’s such a great book club.
The authors summarize the term:
“Biomineralisation names the process by which organisms create organic matter from minerals, usually to give structure, strength, hardness or protection in the organism’s body…organisms produce minerals by absorbing metal ions from their environments and combining them with specialised proteins in the formation of hardened or reinforced mineralised tissues.”
The chapter discusses several examples of biomineralization that bring attention to the creative poetics of non-human life forms. The authors underscore how our attention to these processes “offers an opportunity for nurturing a greater degree of collaboration and communication with these organisms, knowing that as humans we are also biomineral and continuous with non-life.”
Many types of stone are composed of formerly living matter, notably limestone, which is compressed shells and skeletons from an ancient ocean. But thrombolites go a step further in blurring the boundary between organism and rock. They are actively alive, with photosynthesizing microbial mats continuously secreting calcium carbonate, building stone as a byproduct of being alive.
Sage Lewis Surface Study (Lago Sarmiento), unique instant (Kodak Minishot) dye sublimation print, 3 x 3 inches
This return to studying Lago Sarmiento has helped me make a broader connection to the origins of life on Earth, and perhaps, life on other planets. This is because sites such as Sarmiento are crucial for the study of life on Mars. The lake is alkaline and very salty. It is a closed basin, meaning it has no outflow. The pH of the water is equivalent to baking soda. The conditions in which the cyanobacteria thrive here are rare and extreme, inhospitable to most species. In an earlier stage of Earth, the ancestors of these organisms generated the first oxygen that changed the ecology of the entire planet. It seems most likely that if we someday find evidence of life on Mars, it will be ancient and microbial. For that reason, Lago Sarmiento is a fascinating Mars Analog.
Sage Lewis Water Edge (Lago Sarmiento), unique instant (Kodak Minishot) dye sublimation print, 3 x 3 inches
For my own artistic research, I place these images in the context of an ongoing series Above and Below. The series looks at surfaces that divide and obscure worlds of matter based on our human perspective of vision; the Earth’s surface, the water’s surface, the atmospheric layers, and so on. The question of a double-sided surface is an interesting one in the world of thrombolites, as they continually grow outward and create new surfaces, covering the ones beneath. As the surface of the lake recedes, mainly due to evaporation, more thrombolites are exposed.
Alessandro Airo, PhD Thesis Chapter 3, Supplementary Video 6 illustrating photosynthetic growth of thrombolites at Lago Sarmiento. 2010. Stanford University, Department of Geological and Environmental Sciences.
Alessandro Airo, Video Still from supplementary dissertation files illustrating photosynthetic growth of thrombolites at Lago Sarmiento. 2010. Stanford University, Department of Geological and Environmental Sciences.
The growth of microbial mats is sometimes referred to as laminations. While stromatolites, such as those at Shark Bay, grow in thin, linear laminations, the thrombolites form clotted, bulbous laminations. In his dissertation on the subject, Alessandro Airo worked on developing a computer model animation to illustrate this formation of growth as pictured above. I love the articulation of lines expressed in pixels that, together, create a subtle rainbow-interference on the screen.
This year I have been scanning and documenting several series of Kodak Minishot prints, including the ones from Lago Sarmiento. The Minishot is somewhat of a toy instant camera, except that instead of using film like a Polaroid, the Minishot is actually a printer. The cartridge of paper is inserted, and with a point-and-shoot digital capture, the paper slides in and out of the slot as it is coated with color in three passes of dye sublimation: yellow, magenta, and cyan, followed by a clear protective lamination.
The Minishot that I use has no memory, so these are unique prints. After the print is made, the camera is “blank” and there is no record of the image, aside from the print in your hand. As a kind of “poor image” the color, contrast, and tonal range are very limited. I have tested and pushed the camera-printer to perform over the course of geologic investigations in Nova Scotia, Oregon, Chile, and Argentina, noticing how it responds to different lighting and color conditions.
Kodak Minishot “Lamination” print showing tidal river thick with sediment, Mavillette Beach, Nova Scotia.
Working with this pedestrian device echoes some of the challenges of planetary imaging: seeing through the limitations of technology, and finding a new way of seeing within such uncontrollable variables. I have come to appreciate how, in the right circumstances, the construction of the Minishot image can produce an almost painterly layering of color and mark. This happens because of the dye sublimation layering process. I am calling these prints Laminations, because they are essentially thin ink splotches that gently cohere into a picture.
Sage Lewis Water Edge No. 2 (Lago Sarmiento), unique instant (Kodak Minishot) dye sublimation print, 3 x 3 inches
Sage Lewis, Lago Sarmiento, unique instant (Kodak Minishot) dye sublimation print, 3 x 3 inches
There is a lot still to be learned about Cyanobacteria. Many strains and characteristics are still being discovered. Until recently, it was thought that the formation of stone only occurred as an excretion outside of the cell. However, in recent years, scientists have discovered some strains that form calcium carbonate inside the walls of their cellular body. This is leading to research on whether the cells can trap and absorb industrial pollutants from wastewater such as strontium and barium. Additionally, scientists are in the early stages of exploring certain types of cyanobacteria as a mechanism to metabolize microplastic waste. These organisms have been observed colonizing the surfaces of floating plastics and some can produce enzymes that digest and bio-degrade the plastics. More research is needed, but wouldn’t it be a miraculous twist if the same organisms that brought oxygen into the toxic-soup atmosphere of early Earth could help mitigate the plastic sludge that plagues our present-day oceans?
As we think about the search for life on Mars or elsewhere, I hope that it connects us more deeply with the wonders of Earth, which, by extension or by analogy, lead us to a greater understanding of planetary bodies everywhere.
Sources and Further Reading:
Alessandro Airo Dissertation, Stanford, 2010. https://purl.stanford.edu/rw416bs9212 Stanford University, Department of Geological and Environmental Sciences.
Microbial degradation of microplastics: Effectiveness, challenges, and sustainable solutions
Swimming with Stromatolites at Shark Bay
Intracellular Ca-carbonate biomineralization is widespread in cyanobacteria
A living carbonate factory: how do cyanobacteria make rocks? (Calcification in Cyanobacteria)
Fascinating to read this, and hopeful too!
Really fascinating read, Sage! Wouldn’t be amazing if this research could lead to a solution to plastic waste and environmental toxins? Especially as I look out my window now to a red sky from wildfire pollution over our river. 💔