  We show that the degrees of freedom associated with magnetic monopole- and
vortexlike gluonic configurations make a strong contribution to the anomaly of
the energy-momentum tensor of Yang-Mills theory in the deconfinement phase
immediately above the critical temperature. As is well known in
zero-temperature Yang-Mills theory, the monopoles and vortices are constituents
of a generic gluonic object in which the two neighbor monopoles are connected
together by a segment of vortex string. Our results provide evidence that the
monopole-vortex chains in SU(2) gauge theory and their SU(3) counterparts, the
monopole-vortex nets, are thermodynamically relevant degrees of freedom in the
gluonic plasma.
