the color tells how much salt there is left in the water. green colors come from special algae. these algae are there in low to mid salinity ponds (ponds with little salt in the water). in middle to high salinity ponds, an alga called dunaliella salina shifts the color to red. millions of tiny brine shrimp create an orange cast in mid-salinity ponds. other bacteria such as stichococcus also contribute tints. these colors are especially interesting to airplane passengers or astronauts passing above due to their somewhat artistic formations of shape and color.