Particles provide an important transport mechanism for distributing ch
emically and biologically reactive elements in the ocean. To aid in pr
edicting the fate of colloidal particles, we update an existing model,
developed by Farley and Morel [1986] for predicting particle sediment
ation rates in the presence of aggregation. We add some effects of the
fractal structure of the particles as well as the hydrodynamic intera
ctions between particles. Changes due to the hydrodynamics have a less
er effect than the fractal dimension. Simulated sedimentation rates ca
n vary by as much as 6 orders of magnitude as the fractal dimension is
varied between D = 3 and D = 2. Following Farley and Morel we develop
simple expressions for the sedimentation rate. We make use of special
initial conditions and particle input rates as well as a value of 1 f
or the particle stickiness. Introducing the particle fractal dimension
revealed limitations with this class of models, restricting the range
of D which we could successfully use.