Modern microbial landscape: Aerial mapping of microbially induced sedimentary structures forming in a coastal sabkha

ABSTRACT Microbially induced sedimentary structures (MISS) are considered important for understanding primitive life on Earth and for guiding the search for life on other planets. These structures are regarded as macroscopic fossils of early communities of unicellular organisms that did not produce skeletons or shells. In this study, field observations and aerial imagery were combined to investigate MISS in the Dohat Faishakh sabkha in Qatar, a modern evaporitic environment whose intertidal zone is extensively colonised by microbial mats known to generate MISS through interactions with sedimentary processes. Unmanned aerial vehicle (UAV) imagery was used to produce an orthomosaic covering an area of 240 × 180 meters, capturing a continuous microbial landscape. With few exceptions, a clear correspondence was observed between the MISS identified in the field and those detectable from an aerial perspective. Based on the UAV orthomosaic, a map was generated showing the distribution of different MISS within the intertidal zone: (1) polygonal mats with rounded or angular corners, formed through shrinkage cracking and subsequent biomass regrowth; (2) reticulate surface mats, whose origin appears to be controlled primarily by biological processes; (3) erosional patches in the microbial mat, resulting from hydrodynamic disruption; and (4) circular patches associated with gas domes in the microbial mats. The size of these MISS was measured in representative portions of the mapped area, and their spatial distribution was analysed to identify diagnostic features for distinguishing them from conventional desiccation cracks and other structures produced by purely physico‐chemical processes. The dataset acquired may serve as a reference for recognising similar MISS in ancient outcrops, on Earth and potentially on Mars. It is demonstrated that several MISS types previously described in the literature can be identified from aerial imagery alone and that not only their individual morphologies but also their spatial arrangements can assist in recognising these morphological biosignatures.