AHABS... Issue Four

Stomatella varia , the Best Grazing Snail


Ronald L. Shimek, Ph. D.

Ecosystems And Why They Should Matter To Aquarists

A well-constructed and maintained coral reef aquarium is an excellent analogue of an ecosystem. This is true even though, in many ways, it really isn't much like a true coral reef: it is both far too simplified and way too small to be a real reef; however, those considerations don't matter when it comes to ecosystems. I think every aquarist worth her or his salt (water) realizes how limited their little boxes of water, rocks, and animals are. This realization is probably the root cause of the tendency for an aquarist's successive reef aquaria to get bigger and bigger. Nevertheless, even in the small simplified forms that we maintain, our little captive bits of oceanic substance are true ecosystems. As with all ecosystems they are not closed units, both energy and matter pass through them; with the movement of energy providing the motivational force for the movement of matter.

In most natural ecosystems, the energy driving the system is electromagnetic energy received from the sun in the form of light. A few types of deep sea, and possibly some subterranean, ecosystems are powered by energy derived by the chemical breakdown of minerals, but these ecosystems, while very interesting and full of wonderfully bizarre organisms, are not generally found in reef areas and will not be discussed further. In effect, all of the energy that is used in a coral reef comes from the sun.

The Problem Is… Ignorance

Most reef aquarists have a really hard time considering their glass boxes and the organisms therein as “ecosystems.” I think this is primarily due to the fact that few hobbyists have any really good fundamental working understanding of what physically constitutes an ecosystem or how the parts fit together to make it function. Indeed, in general, aquarists show an appalling, and fundamental, misunderstanding of virtually every aspect of the functionality of the biosphere. The failure of basic biological knowledge to thrive in the warm dark and fuzzy recesses of aquarist minds is the root of many hobbyist problems and it is why many of the charlatans who dominate the commercial side of the hobby can have such a hold over people. Simply presented ideas, even if they are demonstrably wrong, often can supersede reality if people are not aware of their fallacies...

An Introduction To Reef Aquaria As Artificial Ecosystems.


Ronald L. Shimek, Ph. D.

A Beginning

This article is meant as the introduction to a series of articles exploring in some detail the concept of treating our reef aquaria as ecosystems and using this concept to develop a viable and usable management scheme for those systems. Of necessity, not all articles in the series will be equally detailed. Some of them, such as this one, will introduce the concepts. Subsequent articles will examine those concepts in more detail, and with specific examples.

I think the best way to manage and maintain a coral reef or marine aquarium of any sort is to consider that it is a “ microcosm ,” or a miniature version of the real world. The term “microcosm” literally means “miniature universe,” and that is truly what such aquaria are. They are miniature, self-contained worlds and in every way that matters, such aquaria are true small ecosystems. They are not natural ecosystems, to be sure, but they are close analogues of them. By treating aquaria as ecosystems, and by managing them as such, aquarists can use the immense body of knowledge about marine ecosystems to their advantage and learn to control those systems in an easily accomplished proactive rather than a reactive manner. In doing so, we manage the systems to avoid disasters rather than continually responding to problems. However, to do this properly those aquarists have to have some understanding of what an ecosystem is, and how it functions. None of this information is particularly difficult to understand or relate to, but the information and concepts involved are not things that most people tend to read about and remember.

Ecosystems ?

So, what is an ecosystem? Simply put, a natural ecosystem is an assemblage of organisms together with their normal environment. But, it is really far more than that, it is an assemblage that is stable over reasonably long periods of time and if it changes, it changes in a predictable manner. Once we know enough about the system, we may be able to predict how the organisms will interact and how the system will operate. In effect, if we know enough about an ecosystem, we may choose to manage that ecosystem in a conscientious and reasonable manner. This is the rationale behind the management scheme for large land-based ecosystem-sized parks such as Yellowstone National Park...

Feeding The Reef Aquarium, A New And Necessary Paradigm


Ronald L. Shimek

paradigms (PAR- b -dimes):

1) ideas or conceptions serving as an example or model of how things should be done; plural.

2) Two small thin U. S. coins worth an aggregate of $ 0.20…


Foods For Reef Animals

It has been known for some time that corals and other coral reef animals must feed. Nonetheless, it is hard to get a good handle on the feeding dynamics of many reef animals. Although coral reefs look really nice in pictures, they are really too difficult to do much work in. We all have seen beautiful pictures of coral reefs; and almost all of those pictures have one thing in common. They are taken at low current velocities or slack water, not during the 20 or more hours a day when the currents are actually roaring across a reef. I can speak from personal experience. Due to a dive master error, a group of divers that I was with were dropped into what was to be a slack water dive at a common dive site in Palau in 1991. In fact, when we entered the water, it turned out to be at the beginning of a strong ebb tide. It was a “interesting” experience to see 1.3 m (4 ft) diameter pieces of tabulate Acropora being “blown” past, rolling along as if they were tumbleweeds, and then sailing off the edge of the reef wall like frisbees from hell, while we tried to shelter by hanging on for dear life in the lee of coral heads. Fortunately we all escaped with our lives, but we were all battered about a lot, and I, for one, can still show you some of the scars. Diving on a reef to take pictures or to do research during maximum current flow is not foolhardy; it is deadly stupid. Consequently, what we know of the diets of most coral reef animals has to be from measurements that are indirectly taken by remote gear, set down on the reef and recovered at some later date, or by methods that equally as remote to the actual feeding events.

Interestingly enough, however, even given what we do know about feeding on a reef as a whole, indicates that aquarists, generally, go about feeding their animals in the wrong way and with the wrong foods. In the words of my sainted grandmother, “Just plain bass- ackwards in all regards.” By examining the types of available food, and the processes of feeding on a reef, I think it will become apparent that many of the problems we have with reef aquaria, such as excess nutrients, excessive growth of undesirable algae, and the inability to keep some animals alive and healthy is simply due to the feeding of inappropriate foods, compounded by feeding in the wrong manner...

Ron Shimek