  We study the transition from laminar to chaotic behavior in deterministic
chaotic coupled map lattices and in an extension of the stochastic
Domany--Kinzel cellular automaton [DK]. For the deterministic coupled map
lattices we find evidence that ``solitons'' can change the {\em nature} of the
transition: for short soliton lifetimes it is of second order, while for longer
but {\em finite} lifetimes, it is more reminiscent of a first order transition.
In the second order regime the deterministic model behaves like Directed
Percolation with infinitely many absorbing states; we present evidence obtained
from the study of bulk properties and the spreading of chaotic seeds in a
laminar background. To study the influence of the solitons more specifically,
we introduce a soliton including variant of the stochastic Domany--Kinzel
cellular automaton. Similar to the deterministic model, we find a transition
from second to first order behavior due to the solitons, both in a mean field
analysis and in a numerical study of the statistical properties of this
stochastic model. Our study illustrates that under the appropriate mapping some
deterministic chaotic systems behave like stochastic models; but it is hard to
know precisely which degrees of freedom need to be included in such
description.
