ROCK WEATHERING BY ASPERGILLIUM NIGER: A COMPARISON BETWEEN TWO MAJOR IGNEOUS ROCKS IN THEIR BIOLOGICAL WEATHERING BEHAVIOR

Aspergillium niger seeded samples were grown for periods not exceeding two weeks in length and then tested for pH, iron, and aluminum as part of a study to determine the weathering potential of this fungal strain on rocks. Filtrates were added to pieces of granite and diabase for an 18 hour period after which the filtrates were retested for pH, iron, and aluminum.

Preliminary results indicate that pH and iron concentration increased for all samples tested after rock pieces were added to the filtrates. Higher iron concentrations were found in the filtrates containing diabase pieces versus those filtrates containing granite pieces.

Comparisons with previous studies using Aspergillium niger and other fungal strains to dissolve rocks suggest that the 18 hour immersion time selected maximizes the amount of dissolution for the rocks.