  We show that the efficient excitation energy transfer in the
Fenna-Matthews-Olson molecular aggregate under realistic physiological
conditions is fueled by underdamped vibrations of the embedding proteins. For
this, we present numerically exact results for the quantum dynamics of the
excitons in the presence of nonadiabatic vibrational states in the
Fenna-Matthews-Olson aggregate employing a environmental fluctuation spectral
function derived from experiments. Assuming the prominent 180 cm$^{-1}$
vibrational mode to be underdamped, we observe, on the one hand, besides
vibrational coherent oscillations between different excitation levels of the
vibration also prolonged electronic coherent oscillations between the initially
excited site and its neighbours. On the other hand, however, the underdamped
vibrations provide additional channels for the excitation energy transfer and
by this increase the transfer speed by up to $30\%$ .
