LSBs do tend to be very rich in atomic hydrogen - account for a significant amount of the galaxy's mass fraction (1-10%).
- Massive LSBs should be detectable through HI surveys.
- However, blind surveys in HI have proven very futile, with no massive LSB detection in the local universe (z < 0.025) .
e.g. Kilborn et al. (2002), Rosenberg & Schneider (2000), Kraan-Krteweg et al.(1999), Knezek (1999), Zwaan et al (1997)