Fluctuations and scaling in aggregation phenomena

We introduce a method which enables us to isolate different sources of fluc tuations during a typical aggregation process. As an example, we focus on t he evolution of islands during irreversible submonolayer epitaxy. We show t hat only spatial fluctuations in island nucleation are required to produce the scaling of their size distribution as determined by Monte Carlo simulat ions. In particular, once the islands are seeded, their growth can be descr ibed in a purely deterministic manner.