philosophic question about different substrates...

[Carlos Arouche]

I know that each kind of substrate (granularity, deep etc...) support different kind of lives....
So in my oppinion, to have the most diverse substrat possible, will benefit the system because of biodiversity it generates.

But yesterday a good friend (and very clever) asked me why do I believe that biodiversity is good for the reef system.

So, I ask support in two points here...

1- What is your oppinion regarding to this subject ?
2- is there any literature or something i could read to learn ?

Best regards.

[lordofthereef]

I think we try to add as much biodiveristy as we can because that is how things balance themselves out in nature. Admittedly, it is incredibly difficult (if not impossible) to totally copy what nature has done, but we tend to try to get as close as we feasibly can. The less biodiverse a system is, the more work we must do to take care of the needs, be that our own manual labor or possibly mechanical work. A fine example with a sand bed is that adding some sand sifting critters to take care of your sand bed will, generally speaking, keep it cleaner and lessen the amount of work YOU must do to maintain it.

[noahm]

This is one of the main reasons LR is used instead of bioballs. The tendency to grow a monoculture population of bacteria is eliminated due to the various microhabitats within/on the rock. The more complete and diverse bacterial populations can take part in all the necessary parts of the waste cycle.

That being said, substrate in an aquarium has some other issues involved. Mainly, it doesn't get thoroughly swirled and shifted by wave action, so it can settle. The different aggregates will act differently in the aquarium as far as the kind of life it will support, plus the way the sand bed is maintained will also affect what lives in it. In general, though, I am almost always a fan of more diversity. It helps prevent overpopulation of some things.

[Dadekster]

I think it is good to have in a closed system as well. In nature bio diversity is good in that it can help in responding to shifting changes in the environment. Most things are tailored to do well in certain areas of a reef, but when things change you have other things that can move in and set up. In a closed system I believe the same principle applies, just on a much smaller scale. Just moving a single rock in your tank can cause profound changes imo. You may have changed the flow of current and the sediment underneath has shifted into new spots for example. It's almost like a mini forest fire. Having a good bio diversity means that there will be animals to fill the new spots.

[KafudaFish]

Biodiversity is usually an indicator of the health of a system whether it is in our tanks or in nature. A diverse system is usually associated with a more stable environment with fewer stressors affecting it. If a stressor impacts the system (chemical, physical or biological) the system has a greater chance of recovery and the time of recovery is decreased. Large bank account vs. small bank account vs. no account but using a credit card payments. All three will cover the cost of an item but #2 is harder than #1 and #3 is the hardest because you have to wait to pay things off.
Impacts are not always negative however because that is how systems undergo succession over time. A good example of that would be forest fires or hurricanes. Some species will not be present until that disturbance and others will not appear until after the first ones have shown up too. Systems that are being impacted demonstrate lower diversity (fewer species) and densities are lower. The composition of the community has shifted toward only those species that are tolerant of the conditions as well. Usually the health, growth rates and reproductive capabilities is lower and the rates of disease are higher. Think about a SPS tank that is high in nitrates and phosphates vs. one that has low levels. What does it look like and how well do the corals grow?
We as reef hobbyists cheer for biodiversity yet we spend much time and effort in removing it from our systems. Bubble algae, hair algae, flatworms, mantis shrimp etc. are all considered pests and anyone reading this probably cringed just a little at the thought that those are in their system.
As far as a mix most will agree that a mix of sizes is good because the animals will colonize based upon the physical environment. Here it would be the interstitial spaces between sand grains. Though over time the sand will settle out and you can get patches of one group in this section of your tank and get another group in another. They will also be found at different sand depths as well.

[Amphiprionocellaris]

Originally Posted by KafudaFish

We as reef hobbyists cheer for biodiversity yet we spend much time and effort in removing it from our systems. Bubble algae, hair algae, flatworms, mantis shrimp etc. are all considered pests and anyone reading this probably cringed just a little at the thought that those are in their system.

I think you raise an interesting point there, and one that I have harped on many times to customers at my old fish store. Algae especially are vilified as pests, when in reality their growth is a sign of a healthy ecosystem. If you look at the reef environment, algae grow very quickly, but they are also grazed very heavily. Of course, in the small space, it can be difficult to maintain the same sort of diversity without harmful interactions, but I would agree 100% that we should try to replicate as much as possible high-diversity environments. Granted, you get into some arguments that go back to the basic approach to reef-keeping employed by an aquarist, but in the end, more diversity almost always leads to a healthier and more natural environment.

As far as the basic question that started this thread, it depends on what level of diversity you're talking about. At the bacterial scale, there may not be much difference between the environments afforded by different particle sizes; they're all huge to a bacterial cell! (for them, grain size effects come into play with things like diffusion and nutrient transport) However, larger-scale life certainly has a preference, so a mix will benefit them. And if you have enough of the larger life (all lumped together into a group known as bio-turbators), they keep the sand bed mixed enough to support themselves. Nifty, huh?

[MyReef 2b Great]

I think because while we know the main things about caring for our aquariums, we could read all day and not know everything. So we want biodiversity do try and have everything possible that might help.

[Carlos Arouche]

I like the responses... but unfortunatelly there is no scientific or pratical analysis on that... It´s just conjectural and logical toughts...

Agree with me ?