Natural processes and the mental shifts we need to make...

We so often discuss natural processes and features in our aquarium work.

There are a lot of interesting pieces of information that we can interpret from Nature when planning, creating, and operating our aquariums. The idea of replicating natural processes and occurrences in the confines of our aquariums, by simply setting up the conditions necessary for them to occur is fundamental to our botanical-oriented approach.

It goes without saying that there are implications for both the biology and chemistry of the aquatic habitats when leaves and other botanical materials enter them. Many of these are things that we as hobbyists observe every day in our aquariums!

Example?

Well, let's talk about our old friend and sometimes nemesis, biofilm.

A lab study I came upon found out that, when leaves are saturated in water, biofilm is at its peak when other nutrients (i.e.; nitrate, phosphate, etc.) tested at their lowest limits. Hmm...This is interesting to me, because it seems that, in our botanical-style aquariums, biofilms tend to occur early on, when one would assume that these compounds are at their highest concentrations, right? And biofilms are essentially the byproduct of bacterial colonization, meaning that there must be a lot of "food" for the bacteria at some point if there is a lot of biofilm, right?

More questions...

Does this imply that the biofilms arrive on the scene and peak out really quickly; an indication that there is actually less nutrient in the water? Is the nutrient bound up in the biofilms? And when our fishes and other animals consume them, does this provide a significant source of sustenance for them? Can you have water with exceedingly low nutrient levels, while still having an abundant growth of biofilms?

Hmm...?

Oh, and here is another interesting observation:

When leaves fall into streams, field studies have shown that their nitrogen content typically will increase. Why is this important? Scientists see this as evidence of microbial colonization, which is correlated by a measured increase in oxygen consumption. This is interesting to me, because the rare "disasters" that we see in our tanks (when we do see them, of course, which fortunately isn't very often at all)- are usually caused by the hobbyist adding a really large quantity of leaves at once, resulting in the fishes gasping at the surface- a sign of...oxygen depletion?

Makes sense, right? 

These are interesting clues about the process of decomposition of leaves when they enter into our aquatic ecosystems. They have implications for our use of botanicals and the way we manage our aquariums. I think that the simple fact that pH and oxygen tend to go down quickly when leaves are initially submerged in pure water during lab tests gives us an idea as to what to expect.

A lot of the initial environmental changes will happen rather rapidly, and then stabilize over time. Which of course, leads me to conclude that the development of sufficient populations of organisms to process the incoming botanical load is a critical part of the establishment of our botanical-style aquariums.

Fungal populations are equally important in the process of breaking down leaves and botanical materials in water as are higher organisms, like insects and crustaceans, which function as "shredders." So the “shredders” – the animals which feed upon the materials that fall into the streams, process this stuff into what scientists call “fine particulate organic matter.”

And that's where fungi and other microorganisms  make use of the leaves and materials, processing them into fine sediments. Allochthonous material can also include dissolved organic matter (DOM) carried into streams and re-distributed by water movement.

And the process happens surprisingly quickly, too.

In experiments carried out in tropical  rainforests in Venezuela, decomposition rates were really fast, with 50% of leaf mass lost in less than 10 days! Interesting, but is it tremendously surprising to us as botanical-style aquarium enthusiasts? I mean, we see leaves begin to soften and break down in a matter of a couple of weeks- with complete breakdown happening typically in a month or so for many leaves. And biofilms, fungi, and algae are still found in our aquariums in significant quantities throughout the process.

So, what's this all mean? What are the implications for aquariums? 

I think it means that we need to continue to foster the biological diversity of animals in our aquariums- embracing life at all levels- from bacteria to fungi to crustaceans to worms, and ultimately, our fishes...All of which form the basis of a closed ecosystem, and perhaps a "food web" of sorts for our little aquatic microcosms.

It's a very interesting  concept- a fascinating field for research for aquarists, and we all have the opportunity to participate in this on a most intimate level by simply observing what's happening in our aquariums every day!

And facilitating this process is remarkably easy:

*Approach building an aquarium as if you are creating a biome.

*Foster the growth and development of a community of organisms at all levels.

*Allow these organisms to grow and multiply.

*Don't "edit" the growth of biofilms, fungal growths, and detritus.

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