Research Details and Recent Findings
by Penny Boston, Associate Professor of Cave and Karst Science

Major questions that my work addresses:

• How much impact do subsurface microorganisms have on the Earth’s lithosphere on short timescales, and over geological time?

• How dependent are subsurface microbe/mineral communities on surface inputs of nutrients, weathering effects, and hydrology?

• How independent are subsurface microbial communities from surface microorganisms and how does this vary between separate subsurface systems?

• What are the original sources of cave microflora: Organisms in groundwater? Air transport of surface organisms? Indigenous aquifer inhabitants? Or cells entombed in the parent rock during the original deposition of sediments?

1. discovery of unique Mn minerals in secondary cave deposits and laboratory demonstration of microbial precipitation of these minerals
2. microbial involvement in concentration of Mn above background by 4 orders of magnitude & concentration of Fe above background by 3 orders of magnitude in secondary mineral deposits
3. demonstration of high bacterial metabolic activity levels (55-80%) in parent rock, leached corroded punk rock, and detrital deposits
4. distinctive d 34 S signatures produced by microbial mats living deep within the rock piping of hydrogen sulfide emitting springs in a volcano-influenced tropical cave
5. in situ bacterial precipitation of gypsum and sulfur within unique exopolysaccharide/bacterial strings in a hydrogen sulfide cave
6. development of new non-consumptive exoenzyme assays for microorganism detection on rocks, buildings/monuments, unconsolidated materials, and waters.