Geosmin and 2-Methylisoborneol Production by Cyanobacteria in Fish Ponds in the Southeastern United States

Abstract

Levels of geosmin and 2-methylisoborneol and composition of phytoplankton communities were determined for water samples collected from 35 fish ponds at Auburn, Alabama, and 34 ponds in west-central Mississippi. In Auburn ponds, geosmin levels ranged from 0.05 to 8.9 µg/l but 2-methylisoborneol was never detected. Highest geosmin concentrations were measured in ponds with plankton blooms dominated by Anabaena species with straight trichomes. In Mississippi ponds, 2-methylisoborneol levels ranged from 0.05 to 76 µg/l. Highest 2-methylisoborneol concentrations were associated with blooms of Oscillatoria cf. chalybea, a cyanobacterium that produces 2-methylisoborneol in unialgal culture. Geosmin was found infrequently in Mississippi pond waters; geosmin levels ranging from 0.05 to 6.25 µg/l could be associated with blooms of Anabaena spiroides, and always concurred with 2-methylisoborneol concentrations ranging from 0.45 to 3.25 µg/l. Neither geosmin nor 2-methylisoborneol at either location could be associated with phytoplankton blooms of Aphanizomenon flos-aquae, Oscillatoria agardhii, Raphidiopsis brookii, or Microcystis aeruginosa.