Scum-simulation of cyanobacterial underwater movement

Abstract

This paper describes the initial development of a computer simulation model of the vertical and lateral movement of a cyanobacterial bloom. Cyanobacteria actively regulate their position vertically within a water column by changing their buoyancy state in response to changing photosynthetic rates. Additionally the cyanobacteria are liable to lateral movement due to wind-induced currents and turbulence in the surface layers. The model may be applied to a range of water-bodies under different wind environments. Initial results predict that periods of severe lake mixing encourages overbuoyancy in Microcystis, resulting in the rapid formation of surface scums. Oscillatoria respond slower to changes in near-surface mixing and are liable to become entrained quickly within weak and turbulent currents. The model results agree well with published field studies. © 1993 Oxford University Press.