  We have investigated the effect of tensor correlations on the depletion of
nuclear Fermi sea in symmetric nuclear matter within the framework of the
extended Brueckner-Hartree-Fock approach by adopting the AV18 two-body
interaction and a microscopic three-body force. The contributions from various
partial wave channels including the isospin-singlet T=0 channel, the
isospin-triplet T=1 channel and the T=0 tensor 3SD1 channel have been
calculated. The T=0 neutron-proton correlations play a dominated role in
causing the depletion of nuclear Fermi sea. The T=0 correlation-induced
depletion turns out to stem almost completely from the $^3SD_1$ tensor channel.
The isospin-singlet T=0 3SD1 tensor correlations is shown to response for most
of the depletion, which amounts to more than 70 percent out of the total
depletion in the density region considered. The TBF turns out to leads to an
enhancement of the depletion at high densities well above the empirical
saturation density and its effect increases as a function of density.
