need help on HW about Reefs

here's one of the questions i have to put on my power point presintion

explain how coral reefs can produce high levels of biological material when the waters surrounding these reefs contain relatively small amountsof nutrients normally needed to support biological production

i cant find the answer anywhere so can some one help me out it's due tommorow this it the 14th question of 16 this has been my favorite project so far in this class

 

Well, i would have to consider the photosynthetic aspect of corals. Many corals are very dependent on photosynthesis, much like plants. Photosynthesis produces sugars, which are used as food for the coral. Once these sugars are consumed they produce biological waste. The use of sunlight as a source of nutrition could help explain how they receive nutrients and produce waste without having to extract as much from the surrounding waters.

 

In the same manner that Tropical Rainforests remain the most productive environments on Earth in spite of tremendously poor soil--coral photosynthesizes. Or more accurately, the cnidarian (the anemone part) obtains most of its nutrition from the zooxanthelle and other alga that inhabit its cells. Sunlight is very energetic, especially in the tropics where it has been filtered by less atmosphere and clearer water. So coral and alga work together to collect the micronutrients (calcium, magnesium, iodine, etc...) and the sunlight. The end product is oxygen, heat, and sugars, with sugar being the main food source for the polyp itself. It is a truly efficient method of extracting energy from the environment. Similar to us, corals often do consume food particles as the float pass in the water column. But unlike us, most of it does not need much or any of this supplementary food source.

 

The key is that photosynthesis is considered primary production and thus 10x more energy is available at the level than the next trophic level--primary consumption. Every subsequent trophic level has 10% of the available energy as the last.

Damsels_R_Cool, go to the library and check out Biology, 5th ed by campbell or Marine Biology, 5th ed by Castro and Huber. These are both standard college level biology texts and will explain these processes in more detail than you will ever want to know.

Hope that helps. Good luck on the PP.