Bloodfalls Geomicrobiology Summary: Samples were collected from subglacial outflow waters associated with Blood Falls discharge during austral summers from 1999-2003. Samples near the outlet of Blood Falls were collected for enumeration and bacterial activity in December of 2000 and 2001. A transect of samples (TransX) was collected in December (see Figure 1), 2002 to capture a profile of releases from Blood Falls into Lake Bonney, starting at the source of the outflow (Trans1) and out onto the moat ice surrounding the lake with increasing distance from the source (Trans2-5). Trans2 was collected from basal ice below the source, Trans3 was collected from waters at the shoreline where Blood Falls meets the moat ice, Trans4 was collected 5 m from the shoreline just below moat ice that melted and refroze daily, and Trans5 was collected under 0.4 m of moat ice approximately 70 m from the shoreline before the moat ice meets the permanent ice cover of Lake Bonney.