Human activities in and near historic Ft. Jefferson may
explain some of the contamination seen at Bird Key and
White Shoal, which are close to these areas; however, there
is no apparent local contamination source to explain the
persistent occurrence of viruses at Black Coral Rock. We
speculate that the sources may be remote, including the
plume from the Mississippi River as it is seasonally
entrained in the Loop Current (Morey et al., 2003). Addi-