G-money said:
It's a general statement. No data was presented on the gut contents of this or any other Acropora FWIW. "Feeding and nutrient absorbtion" could mean DOs, bacteria, mucus, pods, squid, et al....Not to mention there is no evidence presented on how he knows this "fact" about their energy budgets. I need more than his "word", since my experience (and others) shows little need to directly feed them.
Borneman DOES present PLENTY of data in his book and his articles. I only chose not to include them for the sake of brevity. I specifically stated "Without going too crazy with quotes...". Guess I'll include more quotations here.
You see how much tissue covers a typical "SPS" skeleton. Am I to believe they need copious amounts of food to sustain this?
Yes! From Baensch's Marine Atlas Vol. 2 (1997) on page 336 Order Scleractinia: Anatomy;
All polyps of the colony are covered by a thin tissue layer and interconnected by a richly branched vascular system. Hence the nutrients captured by one polyp are food for the entire colony. One or several rows of tentacles are arranged along the circumference of the circular oral disc. Occurring in multiples of 6, the tentacles are armed with batteries of nematocysts. Nematocysts...are predation and defense organelles....Upon tactile stimulation, nematocysts discharge explosively from their capsule, stunning and capturing small planktonic organisms with adhesive threads.
They are opportunistic at best.
I disagree whole heartedly. As noted here and above, they are predatory. From The Modern Coral Reef Aquarium Vol. 1 (Fosså and Nilsen 1996),
Among the consuming organisms on a coral reef the corals themselves are most prominent. In addition to the nutrients they obtain from the products of the photosynthesis of their zooxanthellae, most of them ingest planktonic food.
Perhaps the polyp functions as more than just a mouth.
Agreed. Read on...
Mr. Borneman doesn't address this. None of the hobby authors address this. The polyp is the main site of respiration in the coral.
Again disagree, disagree, and agree.
Borneman (as well as many other authors) address this time and time again. An example, from The Modern Coral Reef Aquarium Vol. 2 (Fosså and Nilsen 1998),
Cnidarians have no specialised organs for the exchange of gases. They obtain their oxygen and emit their carbon dioxide by diffusion through the cell membrane. Thus the animals are dependent on water currents that flow around them and into the individual polyps and out again. Also mentioned,
Cnidarians are in principle animals that depend on planktonic food that is carried to them by the water currents.
It's worth it to look outside the hobby literature for information as well...
Absolutely. In fact hobby authors happily provide outside hobby sources as references mentioned in each of their books/articles. They do the ground work, hopefully sparking an interest with their writings, then point you in the right direction for the material from which they've obtained their information and drawn conclusions.
Coral utilize many different sources for nutrition including (but not limited to) DO, photosynthesis, bacteria, and prey capture. Should you feed your coral? YES! What should you feed them? As seen in this thread, a variety of food works.
