Embracing the few. And the influential.

Okay, the title of this piece sounds like a political treatise, right?

Nah, it's all about my approach botanical-style aquariums. 

There is something I’ve come to embrace since I’ve been playing with botanical-style aquariums:

I like to limit elements.

Huh? 

Yeah, despite having access to an incredible array of botanicals, I have found over the years that it’s more appealing to my personal taste to utilize a less diverse selection of materials in a given aquarium. And it’s not just the aesthetic thing that motivates me to do this- it’s based upon some of the environments I’ve studied.

In many of the habitats we’ve studied, you will find multiple botanical elements, like leaves, seed pods, and twigs. However, the density and combination is profoundly influenced by a number of things.

1. The terrestrial environment surrounding the aquatic habitat. In a dense jungle or rain forest, you’re likely to see a significant diversity of materials. In a flooded savannah or vernal pool, you might see less materials overall, as the density of materials is influenced primarily by what’s “on the ground” already when the water returns.

2. The season. During certain times of the year in many locales, there is a greater density of materials falling into the water, because various trees are shedding leaves and seed pods. Or, you’ll see more botanicals in a given body of water because the water level is lower, and these materials are concentrated.

There’s like a whole area of science devoted to this study of underwater “topography.”

To show you just how geeked-out I am about this stuff, I have literally spent hours pouring over pics and video screen shots of some of these igapo habitats over the years, and literally counted the number of leaves versus other botanical items in the shots, to get a sort of  leaf to botanical "ratio" that is common in these systems.

Geeked out.

Although different areas would obviously vary, based on the pics I've "analyzed" visually, it works out to about 70% leaves to 30% "other botanical items." 

The trees-or more specifically, their parts- literally bring new life to the waters. Some are present when the waters begin rising. Others continue to arrive after the area is flooded, falling off of forests trees or tumbling down from the "banks" of the stream by wind or rain.

Terrestrial trees also play a role in removing, utilizing, and returning nutrients to the aquatic habitat. They remove some nutrient from the submerged soils, and return some in the form of leaf drop. 

Interestingly, studies show that about 70% of the leaf drop from the surrounding trees in the igapo habitats occurs when the area is submerged, but the bulk of that is shedded at the end of the inundation period. 

The falling leaves gradually decompose and become part of the detritus in the food web, which is essential for many species of fishes. This "late-inundation leaf drop" also sets things up for the "next round" - providing a "starter" set of nutrients, doesn't it?

The materials that comprise the tree are known in ecology as "allochthonous material"-  something imported into an ecosystem from outside of it.  (extra points if you can pronounce the word on the first try...) And of course, in the case of trees, this also includes includes leaves, fruits and seed pods that fall or are washed into the water along with the branches and trunks that topple into the stream.  

You know, the stuff we obsess over around here! In fact, everything that we add to our aquariums is, in essence, allochthonous material.

These allochthonous materials support a diverse food chain that's almost entirely based on our old friend, detritus!

Yes, detritus. Sworn enemy of the traditional aquarium hobby...misunderstood bearer of life to the aquatic habitat.

Yeah, the detritus forms not only a part of the food chain in these systems- a very important part in the diet of many of our beloved fishes...it's a literal physical structure that provides an area for fishes to forage, hide, and in some instances, spawn among.

A combination of elements- terrestrial and aquatic. All working together. 

Many other fishes which reside in these flooded forest areas feed mainly on insects; specifically, small ones, such as beetles, spiders, and ants from the forest canopy. These insects are likely dislodged from the overhanging trees by wind and rain, and the opportunistic fishes are always ready for a quick meal!

Interestingly, it's been postulated that the reason the Amazon has so many small fishes is that they evolved as a response to the opportunities to feed on insects served up by the flooded forests in which they reside! The little guys do a better job at eating small insects which fall into the water than the larger, clumsier guys who are more adapted to snapping up nuts and fruits with their big, gnarly mouths! 

And yes, some species of fishes specialize in detritus.

Yeah, detritus again. If we as aquarium hobbyists study the natural habitats of our fishes as diligently as some do the results of last year’s aquascaping contest, it’s easy see that not only is the word “natural” as we use it in the aquarium world really a perversion of the term, you’ll realize that natural aquatic habitats rarely look like what we think they do- and often rely on functions, processes, and materials which we tend to the nk of more as a nuisance than anything else.

Like detritus. And sediments. 

We need to get over our hobby-acculturated fear of these things. In well-managed, well-thought-out aquariums, these elements are as important and functional as they are in the natural habitats we model them after. They power an entire community of organisms which influence the stability, formation, and health of fish communities.

The seasonal shift from terrestrial to aquatic is a remarkable dynamic, with amazing processes that are well worth studying- and replicating- in our aquariums!

As we have discussed more times than you likely care to remember, decomposing leaves are the basis of the food chain, and the they produce forms an extremely important part of the food chain for many, many species of fishes. Some have even adapted morphologically to feed on detritus produced in these habitats, by developing bristle-like teeth to remove it from branches, tree trunks, plant stems, and leaf litter beds. 

Of course, it's not just the fishes which derive benefits from the terrestrial materials which find their way into the water. Bacteria, fungi, and algae also act upon the nutrients released into the water by the decomposing organic material from these plants. 

Plants (known collectively to science as macrophytes) grow in or near water and are either emergent, submerged, or floating, and play a role in "filtering" these flooded habitats in Nature. 

Many are simply terrestrial grasses which have adapted to survival under water for extended periods of time. This adds to the diversity of materials- both living and dead- in these compelling habitats.

A most interesting combination of elements, indeed.

A most compelling model.

A most fascinating example of a "functionally aesthetic" environment that you can duplicate in your home aquarium. Think about the environment, its external influences, the conditions, and the life forms that make use of it the next time you're conjuring up ideas for a new tank...It just might help you create one of the most amazing aquariums you've ever built!

In my experience, this utilization of a few elements, allowed to accumulate, decompose, and function as they do in Nature, do incredible things. For example, my several experiments with botanical-style, "self-feeding" aquariums.

Just a few botanical elements, slowly decomposing and recruiting fungal growths, biofilms, and detritus, have helped me create some very different-looking, yet smooth-functioning closed aquatic ecosystems.

Leave a comment