
Christof SagerMuseum für Naturkunde - Leibniz Institute for Research on Evolution and Biodiversity | MFN · Research
Christof Sager
Doctor of Philosophy
About
17
Publications
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Introduction
For my research in the Atacama Desert (Chile) we combine sedimentological and geochemical soil analysis with photogrammteric reconstruction of polygonal soils - in order to gain insights on their fundamental characteristics, origin and evolution.
Additional affiliations
Education
October 2014 - December 2017
October 2011 - September 2015
Publications
Publications (17)
Life in hyperarid regions has adapted to extreme water scarcity through mechanisms like salt deliquescence. While halite (NaCl) crusts have been intensively studied and identified as one of the last habitats under hyperarid conditions, other less common hygroscopic salt crusts remain unexplored. Here, we investigated newly discovered deliquescent s...
The hyperarid Atacama Desert is one of the driest and oldest deserts on Earth, rendering it a valuable climate archive. However, unraveling its past climate is particularly challenging and the few studied paleoclimate records of the region reveal strong temporal and spatial variabilities. To enhance our understanding of these dynamics we investigat...
Life in hyperarid regions has adapted to extreme water scarcity by using salt deliquescence. Here, we investigated newly discovered deliquescent soil surfaces in the Atacama Desert, containing substantial amounts of nitrates, to evaluate their habitability for microorganisms. We characterized the environment regarding water availability and biogeoc...
The origin of micrometeorites (MMs) from asteroids and comets is well-established, but the relative contribution from these two classes remains poorly resolved. Likewise, determining the precise origin of individual MMs is an open challenge. Here, cosmic-ray exposure ages are used to resolve the spatial origins of 12 MMs collected from urban areas...
In the hyper‐arid Atacama Desert, microbial life thrives near its “dry limit” in scarcely distributed habitats. Fracture networks of salt‐poor sand wedges outlining salt‐cemented polygons on alluvial surfaces in the Yungay region (Chile) represent potential microbial habitats. The degree of soil habitability at the surface (0–5 cm depth) and subsur...
Introduction
The Atacama Desert in northern Chile is one of the driest places on Earth. The hyper-arid conditions are caused by the double rain shadow of the coastal Cordillera in the west and the Andean mountains in the east as well as the cold Humboldt Current along the western coast chilling onshore winds and reducing the uptake of moisture from...
Polygonal networks occur on various terrestrial and extraterrestrial surfaces holding valuable information on the pedological and climatological conditions under which they develop. However, unlike periglacial polygons that are commonly used as an environmental proxy, the information that polygons in the hyper‑arid Atacama Desert can provide is lit...
Background
The hyperarid core of the Atacama Desert is an extremely harsh environment thought to be colonized by only a few heterotrophic bacterial species. Current concepts for understanding this extreme ecosystem are mainly based on the diversity of these few species, yet a substantial area of the Atacama Desert hyperarid topsoil is covered by ex...
The Atacama Desert is the oldest and driest non-polar desert on Earth. Millions of years of hyperaridity enabled salt accumulations through atmospheric deposition. These salts can serve as proxies to decipher the interaction between water and soil as well as to understand the habitability with changing environmental settings. Therefore, we investig...
Polygonal grounds are landscape features commonly associated with periglacial environments originating from freeze-thawing cycles or frost-related processes. However, such a genesis is unlikely for polygonal grounds on alluvial surfaces in the warm and hyper-arid Atacama Desert due to the lack of enduring sub-zero temperatures and limited water ava...
The accumulation of thousands of boulder-sized clasts into boulder fields in the Atacama Desert has been linked to seismic-driven downslope transport, a rare sedimentary process corroborated by this study. We surveyed boulder arrangements occurring in the Atacama Desert and identified three accumulation types for further investigation: a small circ...
The next two rover missions to Mars, ESA/Roscosmos’s ExoMars2020 and NASA’s Mars2020, will carry for the first time Raman spectrometers potentially able to dectect traces of past or present life. To support and interpret future spectroscopic data correctly a better understanding of potential habitable environments and putative biosignatures, using...
The hyperarid core of the Atacama Desert is one of the driest places on Earth and has been for more than 10 million years, rendering the soils a suitable analog environment for Mars, where today´s life detection methods come to their limit of sensitivity. However, a recent study has shown that after rare rainfall events these Mars-like soils can te...
Patterned grounds represent widespread and yet puzzling landscape features on Mars and periglacial regions on Earth and are believed to form through the repetitive deformation of the ground. A better knowledge of their distribution, morphological variability, and processes of formation can give clues about past and recent climatic conditions, the c...
Even in one of the driest places on Earth, the Atacama Desert, life has found adaptive strategies to decreasing amounts of water: from refuges inside or below rocks as endoliths or hypoliths to inside salts in hygroscopic niches (Davila & Schulze-Makuch, 2016). In the hyperarid core though, one of the last refuges for life are inside salt crusts us...