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15. THE ALGAE:
15.1 INTRODUCTION:
Algae is such an all encompassing word, that it means different things to different people, especially to hobbyists. As a general rule hobbyists classify all algae they do not like in the micro-algae category, all other green algae in the macro-algae category, and then have separate classifications for red, and slimy red, and so on. Frequently not very conducive to clearly understanding which type of algae, in fact, the hobbyist is talking about. Some even pronounce the name with a hard g (as in good), and some with a soft g (as in George).
Algae share a lot in common with plants, but they are unique, and often difficult to classify, even when a microscope is used. Some algae are, in fact, very close to bacteria (Cyanobacteria or blue-green algae). Literally thousands upon thousands of species and varieties exist, making it very hard for anyone to identify them easily, except for a few dozen macro-algae types that are commonly kept in aquariums.
Algae can be aquatic or terrestrial. They can exist in fresh and saltwater, even in environments with salinities as high as three times what our aquariums are kept at. The diversity of their habitats is just phenomenal, and such is not an exaggeration either. They adapt quickly to a different milieu and can go in a dormant state, only to reappear when conditions are right again. They are extremely resilient, flexible in their requirements and can be very hard to remove from the aquarium if types that you do not want happen to grow there and do well.
Surprisingly though, the varieties that hobbyists do not care for are, more often than not, associated with lesser water quality conditions.
Such should be an indication that improving the water quality by equipping your tank with an efficient water management system, will in most cases rid the tank of the undesirable varieties.
Algae can be suspended (planktonic), attached (benthic), live on the surface of the water (neustonic), attached to other algae (ephiphitic) and many other in between. They grow particularly well attached to rocks and glass (or acrylic) as just about every hobbyist has found out.
Epilitic algae live on stones, Epipelic on mud and in sand, Epiphytic on plants and other algae, and Episoic algae are attached to to other animals. Yes even that. It should be obvious that algae can grow just about anywhere, and that when conditions are propitious they will do so, often to the dismay of the hobbyist. As should be clear by now, algae are extremely opportunistic.
Algae have been around for billions of years, and range from the infinitesimally small to the very large 180 foot tall Kelp varieties. Some algae grow extremely slowly, while others grow so fast that one gets the impression that you can watch them grow (for example the red slime algae that infest many tanks, are cyanobacteria, and hard to eradicate). Some algae require great amounts of light, while others do much better in low or medium light conditions.
As you may have surmised, because of the infinite number of auspicious conditions, you will have many types of algae in your tank whether you like it or not. The key then will be to maintain the water quality in such a manner that only minimal amounts of undesirable algae are present, and that the ones you want to grow, do so, perhaps even profusely, because of their beneficial qualities. Indeed macro-algae not only clean up the water by removing many toxins, compounds that are harmful in larger quantities, but they also strongly oxygenate the water.
To try and shed some light on the various names you will encounter when reading about algae, a listing is offered for those interested. It is not complete, and it is only one of several classifications that are still used:
Cyanophyta Blue-green Algae Prochlorophyta Blue-green Algae Chlorophyta Green Algae Charophyta Stoneworts Euglenophyta Euglenoids Phaephyta Brown Algae Chrysophyta Golden Yellow-green algae Pyrrhophyta Dinoflagellates Cryptophyta Cryptonomads Rhodophyta Red Algae
Representatives of all can appear in reef aquariums, especially aquariums stocked with many types of so-called live rock from different areas of the world. Frequently though, the ones that are more common are the green, the blue-green (unfortunately) and the red. Some brown algae varieties appear as well in tanks with low levels of lighting. Macro-algae (by the hobbyist's definition) are part of the Chrlorophyta group, a name derived from the fact that they all contain chlorophyll, the very important component necessary for photosynthesis.
The study of algae is called Phycology, and treatises have been written about their ecology, biology, and any other scientific approach than can be taken, unless you are a true algaephile, they are all very dry and no fun to read. Some works however stand out by having brought algae closer to the lay observer.
If you have a more definite interest in algae, you may wish to refer to the following books for more details and information that you can use in your tank's management:
William R. Taylor, The University of Michigan Press, Second Printing of the Second Edition, 1962.
To contact Albert J. Thiel About Albert J. Thiel
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