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J Jl the molecular oxygen produced is not so problematic. When the anemone is illuminated by high intensity light, the energetic UV wavelengths in the presence of photosensitizing agents such as chlorophyll and flavins act synergistically to produce singlet oxygen and the superoxide radical (0?"), which is very reactive and readily forms hydrogen peroxide H7O2 (Shick, 1991). If you've ever poured hydrogen peroxide on a cut or put it in your hair you know it is also very reactive, and not something you want accumulating in your tissues! Dykens and Shick (1982) describe the enzymatic defenses utilized to counter the effects of the superoxide. In one strategy the enzyme superoxide dismutase keeps cellular levels of superoxide low while other enzymes, catalase and peroxidase, convert the hydrogen peroxide produced into water and oxygen. Other biochemical antioxidants may also be used instead of enzymes (Tapley, Shick and Smith, 1988). Dykens (1984) showed that zooxanthellae have high levels of superoxide dismutase activity, and the enzyme used is a form with copper and zinc ions, a form not known from other unicellular eukaryotic algae.

What is mysterious is the effect of trace elements on this condition. Iodine (as potassium iodide) seems to help prevent this problem, and it is possible that other trace elements help also. Perhaps the trace quantities of copper and zinc from added weekly supplements assist in the formation of the zooxanthellae's special enzymes. Perhaps there is an antioxidant effect achieved by the iodide being converted to iodate, as suggested by Budde-meier in Delbeek and Sprung (1994). With all the talk about antioxidants and health lately, it's no wonder this has application to the subject of reef corals, anemones, etc.

Insufficient light is also a problem, however, corallimorphs will readily indicate this. When light levels are too low, corallimorphs take on a typical trumpet-like shape, stretching upwards to capture the light (see Delbeek and Sprung, 1994).

The COMPLETE guide to Aquariums

The COMPLETE guide to Aquariums

The word aquarium originates from the ancient Latin language, aqua meaning water and the suffix rium meaning place or building. Aquariums are beautiful and look good anywhere! Home aquariums are becoming more and more popular, it is a hobby that many people are flocking too and fish shops are on the rise. Fish are generally easy to keep although do they need quite a bit of attention. Puppies and kittens were the typical pet but now fish are becoming more and more frequent in house holds. In recent years fish shops have noticed a great increase in the rise of people wanting to purchase aquariums and fish, the boom has been great for local shops as the fish industry hasnt been such a great industry before now.

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