  Quantum Gaussian channels play a key role in quantum information theory. In
particular, the attenuation and amplification channels are useful to describe
noise and decoherence effects on continuous variables systems. They are
directly associated to the beam splitter and two-mode squeezing operations,
which have operational relevance in quantum protocols with bosonic models. An
important property of these channels is that they are Gaussian completely
positive maps and the action on a general input state depends on the parameters
characterizing the channels. In this work, we study the coherence dynamics
introduced by these channels on input Gaussian states. We derive explicit
expressions for the coherence depending on the parameters describing the
channels. By assuming a displaced thermal state with initial coherence as input
state, for the attenuation case it is observed a revival of the coherence as a
function of the transmissivity coefficient, whereas for the amplification
channel the coherence reaches asymptotic values depending on the gain
coefficient. Further, we obtain the entropy production for these class of
operations, showing that it can be reduced by controlling the parameters
involved. We write a simple expression for computing the entropy production due
to the coherence for both channels. This can be useful to simulate many
processes in quantum thermodynamics, as finite-time driving on bosonic modes.
