Methodology.

We describe our products as "sedimented substrates", because that's what they are- consisting largely of clays, sand, soil, and other materials (mineral sediments!) which mimic some of the properties of the soils of South America and other locales that we find so compelling.

Now, one of the first questions people ask about our soils is "What makes them different than the other materials on the market?" Well, I could go on and on, but quite simply, the answer is that these substrates were formulated to replicate the terrestrial soils of these habitats, which become inundated during seasonal rains and flooding.

Forest floor soils in tropical areas are known by soil geologists as "oxisols", and have varying amounts of clay, sediments, minerals like quartz and silica, and various types of organic matter. So it makes sense that when flooded, these "ingredients" will have significant impact on the aquatic environment. This "recipe" is not only compositionally different than typical "off-the-shelf" aquarium sands and substrates- it looks and functions differently, too.

They weren't designed from the get go to replicate say, river, stream, or lake substrates writ large.

And, they weren't intended to be a "go-to" substrate to replace the standard commercial aquarium substrates, because: a) they're hand-mixed, and therefore more expensive, b) they're not specifically "aesthetic enhancements", c) they are not formulated to be general aquatic plant substrates d) because of their composition, they'll add some turbidity and tint to the aquarium water, at least initially (not everyone could handle THAT!)

Rather, the intention was that our first releases "Varzea" and "Igapo" were formulated to be "transitional" substrate materials- starting out as terrestrial, able to grow some grasses and plants, and eventually becoming saturated and ultimately, submerged, transitioning to a fully "aquatic" substrate material.

Perfect for use in our "Urban Igapo" simulations, which is exactly what we developed them for...you know, the classic case of "scratching your own itch!"

Of course, this begs the question, "Can't they just be used like 'conventional' aquarium substrates from the start?"

And the answer is, "Yeah, they could. However, what will happen, because of their ingredients, is that they will create cloudy, turbid water in your aquarium for a while." There is a reason why materials like fine clays and mineral sediments haven't been particularly popular ingredients in aquarium substrates before!

Some of the materials will not saturate immediately causing this turbidity for several days or more. Ultimately, however, the materials will settle out and you'd be good to go. If you're okay with this initial turbidity, go for it from day one!

Oh, and you shouldn't rinse this substrate. Use it right out of the bag.

One of the pleasant surprises of the "NatureBase" line has been that they do grow aquatic plants- quite well, actually. Surprising to us, because some of the ingredients that we used in our formulation aren't specifically well-known for growing plants. However, the others are more nutritious, and the "pluses outweigh the minuses", apparently! 

Okay, enough of the "mini infomercial" on sedimented substrates!

And, yes, we add a lot of botanical material to the substrates in our tanks. It's another fundamental aspect of what we do. It's part of the way that botanicals actually "work" in aquatic environments.

The texture and chemical composition of the botanicals' exteriors is really well-suited for the recruitment and growth of biofilms and fungal populations- important for the biological diversity and "operating system" of the aquarium, as we've talked about numerous times here. This is such an easily overlooked benefit of using natural materials in the aquarium.

Damn, this is starting to sounds very familiar, huh?

And of course, as we know, terrestrial botanical materials, when submerged in water for extended periods of time, decompose. If there is one aspect of our botanical-style aquariums which fascinates me above almost anything else, it's the way they facilitate the natural processes of life- specifically, decomposition.

Decomposition is fundamental to the botanical style aquarium.

We use this term a lot around here...What, precisely does it mean?

Utilizing botanical materials and leaves in your tank, and leaving them in until they fully decompose is as much about your aesthetic preferences as it is long-term health of the aquarium.

It's a decision that each of us makes based on our tastes, management "style", and how much of a "mental shift" we've made into accepting the transient nature of materials in a botanical-style aquarium and its function. There really is no "right" or "wrong" answer here. It's all about how much you enjoy what happens in Nature versus what you can control in your tank. Nature will utilize them completely, as she does in the wild.

I tend to favor Nature, of course. But that's just me.

And of course, we can't ever lose sight of the fact that we're creating and adding to a closed aquatic ecosystem, and that our actions in how we manage our tanks must map to our ambitions, tastes, and the "regulations" that Nature imposes upon us.

Yes, anything that you add into your aquarium that begins to break down is bioload.

Everything that imparts proteins, organics, etc. into the water is something that you need to consider. However, it's always been my personal experience and opinion that, in an otherwise well-maintained aquarium, with regular attention to husbandry, stocking, and maintenance, the "burden" of botanicals in your water is surprisingly insignificant.

Even in test systems, where I intentionally "neglected" them by conducting sporadic water exchanges, once I hit my preferred "population" of botanicals (by buying them up gradually), I have never noticed significant phosphate or nitrate increases that could be attributed to their presence.

Understand that the process of decomposition is a fundamental, necessary function that occurs in our aquariums on a constant basis, and that botanicals are the "fuel" which drives this process. Realize that in the botanical-style aquarium, we are, on many levels, attempting to replicate the function of natural habitats- and botanical materials are just part of the equation.

And of course, these botanical materials not only offer unique natural aesthetics- they offer enrichment of the aquatic habitat through their release of tannins, humic acids, vitamins, etc. as they decompose- just as they do in Nature.

Leaves and such are simply not permanent additions to our 'scapes, and if we wish to enjoy them in their more "intact" forms, we will need to replace them as they start to break down. This is not a bad thing. It just requires us to "do some stuff" if we are expecting a specific aesthetic. 

This is very much replicates the process which occur in Nature, doesn't it? Stuff like seed pods and leaves either remains "in situ" as part of the local habitat, or is pushed downstream by wind, current, etc. - and new materials continuously fall into the waters to replace the old ones.

Pretty much everything we do in a botanical-style blackwater aquarium has a "natural analog" to it! 

These materials are typically broken down by fungi and bacteria in aquatic environments. Inputs of terrestrial materials like leaf litter and seed pods into aquatic habitats can leach dissolved organic carbon (DOC), rich in lignin and cellulose. Factors like light intensity, mineral hardness, and the composition of the aforementioned bacterial /fungal community all affect the degree to which this material is broken down into its constituent parts in this environment.

Hmm...something we've kind of known for a while, right?

So, lignin is a major component of the "stuff" that's leached into our aquatic environments, along with that other big "player"- tannin.

Tannins, according to chemists, are a group of "astringent biomolecules" that bind to and precipitate proteins and other organic compounds. They're in almost every plant around, and are thought to play a role in protecting the plants from predation and potentially aid in their growth. As you might imagine, they are super-abundant in...leaves. In fact, it's thought that tannins comprise as much as 50% of the dry weight of leaves!

Whoa!

And of course, tannins in leaves, wood, soils, and plant materials tend to be highly water soluble, creating our beloved blackwater as they decompose. As the tannins leach into the water, they create that transparent, yet darkly-stained water we love so much!  

In simplified terms, blackwater tends to occur when the rate of "carbon fixation" (photosynthesis) and its partial decay to soluble organic acids exceeds its rate of complete decay to carbon dioxide (oxidation).

Chew on that for a bit...Try to really wrap your head around it...

And sometimes, the research you do on these topics can unlock some interesting tangential information which can be applied to our work in aquairums...

Interesting tidbit of information from science: For those of you weirdos who like using botanicals, leaves and such in your aquariums, but hate the brown water (yeah, there are a few of you)- you can add baking soda to the water that you soak your wood and such in to accelerate the leaching process, as more alkaline solutions tend to draw out tannic acid from wood than pH neutral or acidic water does. Or you can simply keep using your 8.4 pH tap water! 

MORE "ARMCHAIR SPECULATION": This might be a good answer to why some people can't get the super dark tint they want for the long term...If you have more alkaline water, those tannins are more quickly pulled out. So you might get an initial burst, but the color won't last all that long...

This is something that we need to do a lot more research on. In the end, I'm still a huge believer in the use of reverse osmosis/deionized (RO/DI) water exclusively for botanical-style aquariums. It gives us the best chance of not only manipulating water chemistry characteristics to those we prefer, it also gives us the ability to reap maximum benefits from natural botanical materials- both aesthetically and functionally.

We're also seeing a growing body of science-backed evidence that humic substances, a key component of "blackwater" have significant health benefits for fishes, and may be among the most important factors which contribute to their health in both the wild and in captivity.

This revelation backs up what many aquarists who dabbled with catappa leaves and bark and other stuff in botanical-influenced aquariums, particularly Betta breeders in Southeast Asia, have asserted for years. In particular, it's thought that these compounds, derived from botanicals, have anti-fungal and anti-parastic properties, and offer protection against oxidative DNA damage and from physiological stressors.

With these health benefits now more clearly understood, there are more reasons than ever to appreciate the role that an environment which accumulates these humic substances can play in overall fish health.

Although the health benefits to fishes are fascinating and actually somewhat of a "game changer", like many hobbyists, my interests lie with the creation of aquarium that present a more natural-looking, functional aesthetic. The physiological benefits are a sort of "collateral bonus!"

And it always seems go back to leaves, doesn't it?

Leaves, the "jumping off point" of our botanical obsession, form a very important part of the aquatic habitats which we obsess over.

It is known by science that the leaf litter and the community of aquatic animals that it hosts is, according to one study, "... of great importance in assimilating energy from forest primary production into the blackwater aquatic system." 

There is something that calls to me- beckons me- to explore, to take note of these habitats and their intricate details- and to replicate some of their features in an aquarium- sometimes literally, or sometimes, simply taking components that I find compelling and utilizing them in my tanks.

Habitats like flooded forests and streams also function as a means to preserve the nutrients that would be lost to the forests which would inevitably occur if all the material which fell into the streams was simply washed downstream. The fishes, crustaceans, and insects that live in the leaf litter and feed on the fungi, detritus, and decomposing leaves themselves are very important to the overall habitat.

In this world of decomposing leaves, submerged logs, twigs, and seed pods, there is a surprising diversity of life forms which call this milieu home. And each one of these organisms has managed to eke out an existence and thrive. 

A lot of hobbyists not familiar with our aesthetic tastes will ask what the fascination is with throwing palm fronds and seed pods into our tanks, and I tell them that it's a direct inspiration from nature! Sure, the look is quite different than what has been proffered as "natural" in recent years- but I'd guarantee that, if you donned a snorkel and waded into one of these habitats, you'd understand exactly what we are trying to represent in our aquariums in seconds!

Learning more about the dynamics of stream habitats and the ecology of the surrounding terrestrial environments is just one fascinating and compelling area of study that we as aquarists can really get into.

Yes, it requires some study. It requires trying some new and seemingly wacky ideas (encouraging the accumulation of detritus, decomposing leaves, and epiphytic biofilm growth, for one thing!), and embracing some different aesthetics in our aquariums.

Let's focus on this "functional" dynamic for a second.

When we look to Nature, it's increasingly obvious that we can replicate much of it in our aquariums.This quote from a paper by Mendonca, et al, tells me us many cool things about the habitats we love to replicate:

"In Central Amazonia, terra firme environments (uplands that are not seasonally flooded) are drained by streams that have acidic waters due to the presence of humic and fulvic acids. The waters are poor in nutrients and the forest canopy impairs light penetration to the stream surface, so aquatic plants are virtually nonexistent (Junk and Furch, 1985; Walker, 1995).

In these oligotrophic environments, food chains are dependent on allochthonous material from the forest, such as pollen, flowers, fruits, leaves, and arthropods (Goulding, 1980; Goulding et al., 1988; Walker, 1991). However, small fishes are frequently abundant, and 20 to 50 species may occur in a single stream (Lowe-McConnell, 1999; Sabino, 1999)."

Studies indicate that an increase in species "richness" is positively related to the habitat complexity and shelter availability as well as current velocity and stream size, and that substrate, depth and current speed are among the most important physical features in many bodies of water, which contribute to the formation of numerous "microhabitats", all with fascinating ecology, environmental parameters, and fish population diversity.

 Stuff we've barely tapped into in the aquarium world yet!

Despite their impermanence, botanical materials function as diverse harbors of life, ranging from fungal and biofilm mats, to algae, to micro crustaceans and even epiphytic plants. Decomposing leaves, seed pods, and tree branches make up the substrate for a complex web of life which helps the fishes that we're so fascinated by flourish.

It's a lot to take in. A lot to consider. Yet, these natural components form the cornerstone of our methodology.

Stay thoughtful. Stay educated. Stay observant. Stay patient...

And Stay Wet.

Scott Fellman

Tannin Aquatics