title: Model Simulation of Diurnal Vertical Migration Patterns of Different-Sized Colonies ofMicrocystisEmploying a Particle Trajectory Approach.
abstract: Microcystis, a genus of potentially harmful cyanobacteria, is known to proliferate in stratified freshwaters due to its capability to change cell density and regulate buoyancy. In this study, a trajectory model was developed to simulate the cell density change and spatial distribution ofMicrocystiscells with nonuniform colony sizes. Simulations showed that larger colonies migrate to the near-surface water layer during the night to effectively capture irradiation and become heavy enough to sink during daytime. Smaller-sized colonies instead took a longer time to get to the surface. Simulation of the diurnally varyingMicrocystispopulation profile matched the observed pattern in the field when the radii of the multisized colonies were in a beta distribution. This modeling approach is able to take into account the history of cells by keeping track of their positions and properties, such as cell density and the sizes of colonies. It also serves as the basis for further developmental modeling of phytoplanktons that are forming colonies and changing buoyancy.
authors: Graduate Institute of Environmental Engineering, National Taiwan University , Taipei, Taiwan, Republic of China .
authors: Yu Ching
authors: YC
authors: Chien
authors: Shian Chee
authors: SC
authors: Wu
authors: Wan Ching
authors: WC
authors: Chen
authors: Chih Chung
authors: CC
authors: Chou
keywords: Microcystis; buoyancy regulation; stratification; trajectory model; vertical migration
references: J Environ Sci (China). 2004;16(2):288-92
references: 15137657
references: Microb Ecol. 2005 Apr;49(3):468-73
references: 16003471
references: Biotechnol Bioeng. 1982 Jan;24(1):143-52
references: 18546106
references: Appl Environ Microbiol. 2003 Feb;69(2):787-95
references: 12570996
references: N Engl J Med. 1998 Mar 26;338(13):873-8
references: 9516222
references: Appl Environ Microbiol. 2001 Jan;67(1):278-83
references: 11133456