Brookes, J.Ganf, G.Oliver, R.2006-07-192006-07-192000Journal of Plankton Research, 2000; 22(8):1579-15890142-78731464-3774http://hdl.handle.net/2440/12218© Oxford University Press 2000The literature suggests that relative gas-vesicle volume and metabolic activity differ between individuals within natural populations of cyanobacteria. We demonstrate, using flow cytometry and fluorescein diacetate (FDA) conversion rates, that individual relative gas-vesicle volumes differed by 6.7- and 4.6-fold, and individual cell photosynthetic rates ranged from 0.026 to 0.127 and from 0.075 to 2.415 fmol O2 cell–1 min–1 within phosphorus-starved and phosphorus-replete Microcystis aeruginosa populations, respectively. The observation that there is considerable heterogeneity in gas-vesicle volume and cell metabolic activity in cultured populations suggests that this could also contribute to heterogeneity in buoyancy of field populations.enJournal article000100000610.1093/plankt/22.8.15790000887005000102-s2.0-003385278764005Brookes, J. [0000-0001-8408-9142]Oliver, R. [0000-0003-2238-1740]