  We study the performance of two measures of non-Markovianity in detecting
memory effects in two-qubit dephasing channels. By combining independent
Markovian and non-Markovian noise on the qubits, our results show that the
trace distance measure is able to detect the memory effects when at least one
of the local channels displays non-Markovianity. A measure based on channel
capacity, in turn, becomes non-zero when the global two-qubit dynamics shows
memory effects. We apply these schemes to a well-known superdense coding
protocol and demonstrate an optimal noise configuration to maximize the
information transmission with independent local noises.
