Salt ponds in San Francisco, CA. The palette of colors that makes the salt ponds so beautiful is created by a complex ecosystem. The colors range from pale green through deep coral pink to bright red. The color indicates the salinity of the ponds. Micro-organisms change their hues as the salinity of the pond increases. In low to mid-salinity ponds, green algae is predominant, giving the water a deep greenish cast. In middle to high salinity ponds, the Dunaliella produces a red pigment.