Caroline S. Rogers 1979 <p>San Cristobal Reef, Puerto Rico, was the site of a community metabolism study based on a new upstream-downstream method with experimental channels 4 m deep. Net productivity rates varied from 0.03 to 1.85 g O₂m^&ndash;2 reef area&middot;h^{&shy;&ndash;1} (<i>x&nbsp;</i>= 0.39; <i>n</i> = 59). Respiration measurements of one reef section from which light was excluded ranged from 0.26 to 0.48 g O₂&middot;m^&ndash;2 reef area&middot;h^&ndash;1. The linear regression equation <i>y</i> = 0.58<i>x</i> &ndash; 0.18, where <i>y</i> = g O₂&middot;m^&ndash;2 reef area&middot;h^{&shy;&ndash;1} and <i>x</i> = mEin&middot;m^&ndash;2&middot;s^&ndash;1, describes the correlation between light and metabolism at this site. Net primary productivity was 2.45 g O₂&middot;m^&ndash;2 reef area and gross primary productivity 5.42. The ratio of gross primary productivity to 24-h respiration was 0.7. Productivity rates of this heterotrophic zone are lower than those reported for shallower reef zones with greater algal cover.</p> application/pdf 10.4319/lo.1979.24.2.0342 en Association for the Sciences of Limnology and Oceanography, Inc. The productivity of San Cristobal Reef, Puerto Rico article