Bat urea-derived minerals in arid environment. First identification of allantoin, C4H6N4O3, in Kahf Kharrat Najem Cave, United Arab Emirates

Audra, Philippe; Bosák, Pavel; Gázquez, Fernando; Cailhol, Didier; Skála, Roman; Lisá, Lenka; Jonášová, Šárka; Frumkin, Amos; Knez, Martin; Slabe, Tadej; Hajna, Nadja Zupan; Al-Farraj, Asma

doi:10.5038/1827-806x.46.1.2001

Cited by 13 publications

(4 citation statements)

References 18 publications

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“…Urea on the surface of the speleothems probably originated from bat guano and urine, which also contributes to the organic matter and nutrient enrichment in the caves (e.g. McFarlane et al ., 1995; Audra et al ., 2017). Our survey of an undeveloped neighbouring cave, for example, was impeded ca 20 m from the entrance due to numerous bats and a thick layer of bat guano on the ground.…”

Section: Discussionmentioning

confidence: 99%

Carbonate microbialites and chemotrophic microbes: Insights from caves from south‐east China

Ren,

Jones,

Nie

et al. 2024

Sedimentology

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Chemosynthetic microorganisms facilitate microbialite development in many caves throughout the world. In Youqin Cave and Tian'e Cave, located in the Carboniferous–Triassic carbonates on the South China Block, five Quaternary speleothems (stalagmite, stalactite and cave pearl) that are 2.3 to 11.0 cm long were examined for their petrographic, geochemical and microbiological features to reveal how chemotrophs contribute to microbialite growth. In the speleothems, millimetre‐sized stromatolites, thrombolites and calcified microbial mats are characterized by alternating light, calcitic microlaminae and dark, clay and organic‐rich calcite microlaminae. Filamentous (reticulate, smooth, nodular and helical), coccoid and bacilliform microbes, originally carried into the caves from surface soils, are more common in the dark microlaminae/clots than in the light microlaminae. 16S rRNA gene sequencing shows that the biotas in the microbialites are dominated by chemoorganotrophic heterotrophic bacteria, including primarily Sphingomonas, Crossiella and Acinetobacter, and rare Archaea. Diverse metabolic pathways of these prokaryotes, including ureolysis, denitrification and nitrite ammonification, contributed to increases in localized pH and/or dissolved inorganic carbon in these microenvironments, prompting carbonate precipitation. Development of the cave microbialites was probably controlled by the evolution of the cave microbial community as environmental conditions changed. Microbialite growth was probably mediated by the microorganisms that flourished on the speleothem surfaces during periods of low drip water rates and slow calcite precipitation. The change from microstromatolites to microthrombolites was probably linked to a decrease in cell populations in the microbial communities. These cave microbialites provide clear insights regarding the biogenicity and growth mechanisms of chemosynthetic microbialites. Given their association with chemolithotrophic activities that can date back to the Meso‐Archean, cave microbialites provide insights into the biogenicity and growth mechanisms of chemosynthesis‐based microbialites throughout geological history.

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Section: Discussionmentioning

confidence: 99%

Carbonate microbialites and chemotrophic microbes: Insights from caves from south‐east China

Ren,

Jones,

Nie

et al. 2024

Sedimentology

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“…However, this subject has received more attention recently due to a better understanding of the chemical processes involved, the mineralogical evolution of guano, and the role played by bats and their guano on post-speleogenetic cave modification due to condensation-corrosion processes [e.g. 54, 55, 56, 57, 58]. Bats and their guano may influence cave development processes in different ways (Fig.…”

Section: Discussionmentioning

confidence: 99%

Bats as ecosystem engineers in iron ore caves in the Carajás National Forest, Brazilian Amazonia

Piló

Calux²,

Scherer³

et al. 2022

Preprint

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Ecosystem engineers are organisms able to modify their environment by changing the distribution of materials and energy, with effects on biotic and abiotic ecosystem components. Several ecosystem engineers are known, but for most of them the mechanisms behind their influence are poorly known. We detail the role of bats as ecosystem engineers in iron ore caves in the Carajás National Forest, Brazilian Amazonia, an area with > 1,500 caves, some holding ∼150,000 bats. We analyzed the chemical composition of guano deposits in bat caves, radiocarbon-dated those deposits, and elucidated the chemical mechanisms involved and the role the bat guano has on structuring those caves. The insect-composed guano was rich in organic matter, with high concentrations of carbon, nitrogen, phosphorus pentoxide and ferric oxide, plus potassium oxide, calcium and sulfur trioxide. Radiocarbon dating indicated guano deposits between 22,000 and 1,800 years old. The guano pH was mainly acid (from 2.1 to 5.6). Percolating waters in those bat caves were also acid (pH reaching 1.5), with the presence of phosphate, iron, calcium, nitrate and sulfate. Acid solutions due to guano decomposition and possible microbial activity produced various forms of corrosion on the caveś floor and walls, resulting in their enlargement. Caves with active or inactive bat colonies had, on average, horizontal projections 4.5 times larger, areas 4.4 times larger, and volumes 5.0 times bigger than the reginal average, plus more abundant, diversified and bigger speleothems. In an example of bioengineering, the long-term presence of bats (> 22,000 years) and the guano deposits they produce, mediated by biological and chemical interactions along millennia, resulted in very unique ecological, evolutionary and geomorphological processes, whose working are just beginning to be better understood by science. However, the current expansion of mineral activities coupled with the loosening of licensing and cave protection rules is a real conservation threat to the bat caves in Carajás. The destruction of those caves would represent and unacceptable loss of both speleological and biological heritage and we urge that, whenever they occur, bat caves and their colonies must be fully protected and left off-limits of mineral extraction.

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“…11A-C). These minerals are highly soluble and precipitate only under warm and dry conditions or during guano combustion due to an exothermic reaction of guano decay (Onac and Forti, 2011;Audra et al, 2017;Audra et al, 2021).…”

Section: Secondary Mineralsmentioning

confidence: 99%

Geochemistry and 14C dating of guano deposits in the Karaftu Cave, Kurdistan, Iran: implication for paleoenvironment

Amin-Rasouli,

Minami,

Armstrong-Altrin

et al. 2023

Environ Monit Assess

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Karaftu Cave in the northwest of Divandareh includes four oors plus an underground area. The bat hall and its underground area are covered with guano deposits. 14 C dating indicates the onset of guano deposition is about 14260±50 BP years, and its average accumulation rate is about 4.1 mm/yr for depths of 360 to 205 cm. Bacterial and fungal metabolisms decay guano, release acids, and disperse large amounts of microorganisms inside the cave. Interactions between acids and guano caused leaching, dissolution, change in the distribution, and abundance of elements, which leads to the formation of secondary minerals in guano. These variations in minerals and elements also depend on the local climatic conditions. Distribution of elements in the Ce/Ce* verse Pr/Pr* diagram and the correlation coe cient between Ce and Mn display three different paleoclimate conditions (dry, wet, and dry) during the accumulation of the guano. Also, dolomite, phosphate, and iron oxide minerals have been formed during the passage of water through bedrock beneath the guano. This water is unsuitable for drinking and harmful to the organisms in the region. Effect of these acids on the substrate also leads to the collapse of the cave oor, generation of a new underground, fall in the groundwater level, change in the groundwater drainage system, drying of springs around the cave, loss of green cover, and a negative impact on the ecosystem in the region. To keep the cave environment clean and remove these problems, it is better to harvest guano and use it as fertilizer.

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Bat urea-derived minerals in arid environment. First identification of allantoin, C4H6N4O3, in Kahf Kharrat Najem Cave, United Arab Emirates

Cited by 13 publications

References 18 publications

Carbonate microbialites and chemotrophic microbes: Insights from caves from south‐east China

Carbonate microbialites and chemotrophic microbes: Insights from caves from south‐east China

Bats as ecosystem engineers in iron ore caves in the Carajás National Forest, Brazilian Amazonia

Geochemistry and 14C dating of guano deposits in the Karaftu Cave, Kurdistan, Iran: implication for paleoenvironment

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