159-2 Microbe-mineral interactions in hypogene caves

Session: Hypogene Speleogenesis: An Overview of Research in Memory of Dr. Alexander Klimchouk

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Over the last three decades, researchers have recognized the importance of microorganisms for the development of hypogene caves. Hypogene caves—caves that form from rising, deep-seated groundwaters—provide compelling natural laboratories for geomicrobiology research because they often host isolated microbial communities that rely on in situ chemical energy sources, catalyze carbonate dissolution and secondary mineral precipitation, and sometimes support entire isolated ecosystems. Sulfuric acid caves are a subset of hypogene caves that form from the oxidation of hydrogen sulfide in rising anoxic groundwaters. When they are actively forming, they contain robust communities of extremophilic microorganisms that thrive on the chemical energy from sulfide oxidation and act as biological catalysts for sulfuric acid production, limestone dissolution, and the formation of gypsum, elemental sulfur, and other secondary minerals. However, sulfuric acid caves have a long lifetime, and continue to support slower growing microbial communities for millions of years after the sulfidic waters have receded. These relict caves typically have much less chemical energy input, so chemolithotrophic microorganisms often rely on scarce mineral or trace gases resources. We will describe research on microbe-mineral interactions and extremophilic microorganisms above the water table in active sulfuric acid caves, as well as new research on microbial communities in ancient sulfuric acid caves as well as other hypogene caves that may not have had sulfuric acid influence. 

Geological Society of America Abstracts with Program. Vol. 57, No. 6, 2025

doi: 10.1130/abs/2025AM-10020

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