Figure 20. Diatom abundance (z-axis) and percent T. nitzschioides and freshwater diatoms (x-axis) at Hole 1075A. Abundance index: 5 = abundant, 4 = common, 3 = few, 2 = rare, 1 = trace, 0 = barren. T. nitzschioides is an upwelling indicator in the Congo Fan area.