Great article by a well respected chemist. Good find!
It is also a good thing to not that symbiotic corals take up phosphates and ammonia from the surrounding seawater by day and release them at night.
http://www.globalcoral.org/corals_and_coral_reefs.htm
"Zooxanthellae provide a coral with all the sugars it can use; much of it is almost immediately excreted from the coral as mucus. Sugars are used for energy; consequently, zooxanthellae provide fuel, which the coral uses to feed on other things. What zooxanthellae cannot provide are the important nutrients such as proteins, phosphates, minerals, and a host of other materials. They do provide the energy to build and utilize the coral’s own plankton-sampling machinery: the tentacles, the nematocysts, the mouth, and the digestive tissues.
One of the famous questions in biology is: “What is life?” It is amazingly difficult to define all life inclusively. The major property of life, however—its main defining characteristic—is that it evolves. And one of the major characteristics of natural selection is that it removes anything that is costly or unnecessary. All organisms are on a budget, and any organism that spends energy producing unnecessary body parts eventually loses the race to another organism that has eliminated superfluous items. British zoologist Sir Charles Maurice Yonge once famously noted that of all predators, corals devoted the largest proportion of their bodies to food capture and consumption. This property alone tells researchers, and should tell aquarists, that corals need to eat to obtain proteins for new tissue, phosphates for nucleic acids, and many other substances."
http://www.coralmagazine-us.com/content/what-corals-eat
