Dependence of Nebular Heavy-Element Abundance on H I Content for Spiral
  Galaxies
  We analyze the galactic H I content and nebular log(O/H) for 60 spiral
galaxies in the Moustakas et al. (2006) spectral catalog. After correcting for
the mass-metallicity relationship, we show that the spirals in cluster
environments show a positive correlation for log(O/H) on DEF, the galactic H I
deficiency parameter, extending the results of previous analyses of the Virgo
and Pegasus I clusters. Additionally, we show for the first time that galaxies
in the field obey a similar dependence. The observed relationship between H I
deficiency and galactic metallicity resembles similar trends shown by
cosmological simulations of galaxy formation including inflows and outflows.
These results indicate the previously observed metallicity-DEF correlation has
a more universal interpretation than simply a cluster's effects on its member
galaxies. Rather, we observe in all environments the stochastic effects of
metal-poor infall as minor mergers and accretion help to build giant spirals.
