Lichens Bite the Dust : A Bioweathering Scenario in the Atacama Desert

Bioweathering mediated by microorganisms plays a significant role in biogeochemical cycles on global scales over geological timescales. Single processes induced by specific taxa have been described but could rarely be demonstrated for complex communities that dominate whole landscapes. The recently discovered grit crust of the coastal Atacama Desert, which is a transitional community between a cryptogamic ground cover and a rock-bound lithic assemblage, offers the unique chance to elucidate various bioweathering processes that occur simultaneously. Here, we present a bioweathering scenario of this biocenosis including processes such as penetration of the lithomatrix, microbial responses to wet-dry cycles, alkalinolysis, enzyme activity, and mineral re-localization. Frequently occurring fog, for example, led to a volume increase of microorganisms and the lithomatrix. This, together with pH shifts and dust accumulation, consequently results in biophysical breakdown and the formation of a terrestrial protopedon, an initial stage of pedogenesis fueled by the grit crust. © 2020 The Author(s

Ecophysiology and phylogeny of new terricolous and epiphytic chlorolichens in a fog oasis of the Atacama Desert

The Atacama Desert is one of the driest and probably oldest deserts on Earth where only a few extremophile organisms are able to survive. This study investigated two terricolous and two epiphytic lichens from the fog oasis “Las Lomitas” within the National Park Pan de Azúcar which represents a refugium for a few vascular desert plants and many lichens that can thrive on fog and dew alone. Ecophysiological measurements and climate records were combined with molecular data of the mycobiont, their green algal photobionts and lichenicolous fungi to gain information about the ecology of lichens within the fog oasis. Phylogenetic and morphological investigations led to the identification and description of the two new lichen species Ramalina reichenbergeri and Acarospora conafii as well as the lichenicolous fungi that accompanied them and revealed the trebouxioid character of all lichen photobionts. Their photosynthetic response during natural scenarios such as reactivation by high air humidity and in situ fog events were compared to elucidate the activation strategies of this lichen community. Epiphytic lichens showed photosynthetic activity that was rapidly induced by fog and additionally during high air humidity whereas terricolous lichens were only activated by fog

Roccellinastrum, Cenozosia and Heterodermia: Ecology and phylogeny of fog lichens and their photobionts from the coastal Atacama Desert

Some deserts on Earth such as the Namib or the Atacama are influenced by fog which can lead to the formation of local fog oases - unique environments hosting a great diversity of specialized plants and lichens. Lichens of the genera Ramalina, Niebla or Heterodermia have taxonomically been investigated from fog oases around the globe but not from the Atacama Desert, one of the oldest and driest deserts. Conditioned by its topography and the presence of orographic fog, the National Park Pan de Azúcar in the Atacama Desert is considered to be such a lichen hotspot. Applying multi-gen loci involving phylogenetic analyses combined with intense morphological and chemical characterization, we determined the taxonomic position of five of the most abundant epiphytic lichens of this area. We evaluated Roccellinastrum spongoideum and Heterodermia follmannii which were both described from the area but also finally showed that the genus Cenozosia is the endemic sister genus to Ramalina, Vermilacinia, Namibialina and Niebla. As a result, we have described the species Heterodermia adunca, C. cava and C. excorticata as new lichen species. This work provides a comprehensive dataset for common fog lichen genera of the Coastal Range of the Atacama Desert that can be used as a baseline for monitoring programs and environmental health assessments

concatenated_mycobiont_ITS_RPB1

Data contain the alignment of four lichen mycobiont species (Acarospora conafii sp. nov., Placidium sp., Everniopsis trulla, Ramalina reichenbergeri sp. nov.). Data are fasta file that can be opened with the software Mega or Mega X. ITS bp position 1-959; RBP1 bp position 960-1538

concatenated_photobiont_LR3-rbcL-Al1500af

This data file is a fasta format that can be opened with the software Mega or Mega X. It contains a concatenated alignment of lichen photobiont (trebouxioid) sequences of the LR3, rbcl and Al1500af regions. LR3 bp position 1-688; rbcL bp position 689-1619 ; 18S bp position 1620-2327

Ecophysiology and phylogeny of new terricolous and epiphytic chlorolichens in a fog oasis of the Atacama Desert

The Atacama Desert is one of the driest and probably oldest deserts on Earth where only a few extremophile organisms are able to survive. This study investigated two terricolous and two epiphytic lichens from the fog oasis “Las Lomitas” within the National Park Pan de Azúcar which represents a refugium for a few vascular desert plants and many lichens that can thrive on fog and dew alone. Ecophysiological measurements and climate records were combined with molecular data of the mycobiont, their green algal photobionts and lichenicolous fungi to gain information about the ecology of lichens within the fog oasis. Phylogenetic and morphological investigations led to the identification and description of the new lichen species Acarospora conafii sp. nov. as well as the lichenicolous fungi that accompanied them and revealed the trebouxioid character of all lichen photobionts. Their photosynthetic responses were compared during natural scenarios such as reactivation by high air humidity and in situ fog events to elucidate the activation strategies of this lichen community. Epiphytic lichens showed photosynthetic activity that was rapidly induced by fog and high relative air humidity whereas terricolous lichens were only activated by fog