  The subsurface ocean of Europa is a high priority target in the search for
extraterrestrial life, but direct investigations are hindered by the presence
of a thick, exterior ice shell. Here we present spectral line and continuum
maps of Europa obtained over four epochs in May-June 2021 using the Atacama
Large Millimeter/submillimeter Array (ALMA), to search for molecular emission
from atmospheric plumes, with the aim of investigating subsurface processes.
Using a 3D physical model, we obtained upper limits for the plume abundances of
HCN, H$_2$CO, SO$_2$ and CH$_3$OH. If active plume(s) were present, they
contained very low abundances of these molecules. Assuming a total gas
production rate of $10^{29}$ s$^{-1}$, our H$_2$CO abundance upper limit of
$<0.016$\% is more than an order of magnitude less than measured in the
Enceladus plume by the Cassini spacecraft, implying a possible chemical
difference between the plume source materials for these two icy moons.
