A push towards the Pantanal...

Every once in a while, I find myself researching some exotic habitat to replicate in my aquarium, and I'll inevitably mumble to myself something like, "Oh, that's cool! I'm gonna get back to that..."

And of course, I usually do...at some point.

Of course, I tend to be obsessed about a very narrow range of habitats, as is evidenced by my ramblings here and elsewhere, right?

I mean, I admit that you don't have to search very deep into our blog to find at least 100 posts referencing flooded forest floors, particularly in South America; specifically in Brazil.

They've been a focus, an educational vehicle, and an inspiration for all of us in the blackwater/botanical-style aquarium game. Now of course, the flooded igapo forests are but one of hundreds of possible habitats the botanical-style aquarium geek can choose to replicate, or be inspired from.

One look at this habitat and you can't blame me, right?

However, there are some other, very compelling habitats to explore out there!

Today, let's take the most cursory look at a different habitat-The Pantanal- an inspiring place that we've never really touched on much- one which can inspire some amazing aquariums!

One which...isn't "tinted!" Well, not like those igapo, anyways! 

This is a perfect tie-in to a discussion I'm going to have later today with my "Pal in the Pantanal"- Tai Strietman, who's doing his post-grad work in this incredible habitat, and who's amazing pics from this area have graced these pages and our social media feeds for some time now!

THE PANTANAL...

The Pantanal (derived from the Portuguese word "pantano"- meaning "swamp", "wetland", or "marsh") is the largest wetlands region Earth. Full stop. Primarily located within the Brazilian state of Mato Grosso do Sul, it also extends into the state of Mato Grosso, and the nations of Paraguay and Boliva as well! We're talking about region estimated to be as large as 75,00 square miles/195,000 square kilometers!  

It's freakin' huge! 

Essentially a large depression in the earth's crust, the Pantanal constitutes a huge river delta, into which a number of rivers converge, depositing sediments and other biological materials. Now of course, with a habitat this large, there are multiple ecosystems contained in it- as many as 12 have been defined by scientists! 

(Image by Alicia Yo- used under CC BY-SA 3.0)

Now, our main focus is, of course, fishes- and the Pantanal offers plenty of places for fishes to reside in! The cool thing about the Pantanal is that as much as 80% of it is floodplains submerged during the rainy seasons (in which up to 59inches/1,500mm of rainfall have been recorded! That corresponds to water depths which can fluctuate up to 15'/5 meters in some areas!), and is home to an astonishing diversity of fishes and aquatic plants! With it's enormous expanse of shallow, slowly-flowing water (velocities of no more than 4"/10cm per second are typical), dense vegetation tends to be the norm here. 

The water itself tends to be turbid, and perhaps even a bit anoxic at times. And, interestingly, the highest levels of pH and dissolved oxygen in these habitats tend to occur when the water decreases and plant growth is stimulated. Curiously, however, scientists are not 100% certain if this is because of the plants going crazy with photosynthesis, or mixing of the water column due to influx of water. 

(Image by Filipefrazae- Used under CC BY-SA 3.0)

Over 400 fish species call this region home. Interestingly, the "keystone species" of The Pantanal is a snail- the Apple Snail (Ampullaridae), which is a real survivor, as it has both gills and lungs, which makes survival possible during the early part of the flood season when huge amounts of terrestrial plants decay and use up the available oxygen, resulting in suffocation to all of the larger decomposers in the ecosystem.

This remarkable- and fortunate- adaptation enables the humble snail to consume the majority of the dead plant matter and turn it into "fertilizer" for the aquatic plants...And, in a sort of insult, really- the snails become feed for other animals. A rather undignified end for such important creatures, wouldn't you say? 

(The "keystone species"- image by Stijn Ghesquiere, used under CC BY-SA 3.0)

Many of the fishes which are found in The Pantanal are migratory, moving seasonally between the river channels and the flood plain regions. As you might imagine, the bulk of them are detritovorous, feeding on the fine particles from the accumulated sediments and macrophytes (remember them?) within the ecosystem.

Macrophytes supply shelter, food resources and cover for the resident fishes. Still other fishes consume the aquatic insects and microorganisms/biofilms that are recruited in this habitat. Most are well-adapted to the relatively oxygen-poor waters of this vast flood plain.

Characins are represented big-time in this habitat, with species of Moenkhausia, Hyphessobrycon, Pyrhulina, Aphyocharax, and Characidium all present. Oh, and Apisto lovers will be pleased to know that there are some cool ones found there- Apistogramma borellii, A. trifasciata, A. commbrae, and some others. Even species as wide-ranging and diverse as Corydoras, Crenicichla, Otocinculus, Abramites, and Leporinus are found in this ecosystem.

According to most of the studies I read on this ecosystem, the contributing factors to the fish population include stuff like the clarity of the water, the abundance of the food sources (ie, those macrophytes again!), and the connections between lakes and rivers. And, as the water recedes, the available macrophytes tend to settle on the margins of the habitat in the form of...wait for it...our old friend, detritus! 

And during the low-water seasons, the resident fishes tend to occupy the areas where autochthonous resources- materials which formed in the areas where they are found, not from outside of the habitat a la our old friends, the allochthonous resources.  (Damn, we talk about some obscure shit in this blog, huh? You guys are smart!). 

Of course, the seasonal flooding of the marginal lowlands increases the quantity and availability of allochthonous feeding resources for the floodplains and the fishes which reside there. An interesting example of the tight relationship between various habitats in the region, wouldn't you say?

When the water levels rise, the marginal vegetation in the habitats dies off and contributes to the levels of organic matter found in the water. This results in a decrease in dissolved oxygen, pH, and transparency of the water column. This of you who are geeky hardcore biotope hobbyists, who obsess over stuff like creating a tank to represent a habitat in a specific time of year should take note, huh?

Biologists tend to think that the small guys- the characins, specifically, benefit from fast growth, high fecundity (ie; they're prolific!), and rapid colonization capabilities- and that these characteristics tend to determine success in The Pantanal environment. And one more example of this is the "role" of fishes in the Pantanal which consume fruits (which come from the trees adjacent to the wetlands).  Around 150 species of fruit-eating fishes inhabit this system.

When the fishes eat the fruits, they pass the seeds through, well- pooping. Amazingly, it's thought  that they are responsible for the dispersal of as much as 95% of the trees which comprise tropical forests of the region! That's literally the definition of "doing useful shit", IMHO...

Interestingly, the highest levels of pH and dissolved oxygen in these habitats tend to occur when the water decreases and plant growth is stimulated. Scientists are not 100% certain if this is because of the plants going crazy with photosynthesis, or mixing of the water column due to influx of water. 

Aquatic plants found here include such popular aquarium species as Polygonum, Salviania, Pistia, Ludwigia, and others.

So...all of this cool information to process- and we've just touched on the tiniest amount of the most superficial information that can be of interest to botanical-style aquarium hobbyists!

How could we represent the Pantanal in an aquarium?

Well, for starters, you could take a cue from the hardcore biotope community and "pick a season", and build up your "micro-Pantanal" from there! Of course, botanicals are absolutely appropriate for this niche, right? I am thinking of a group of less "tint-capable" materials, such as Latifolia Pods, Dysosxylum Pods, Mokha Pod sections, Parviflora Pods, Puberula Pods, Nypa Palm Flowers, etc. these would represent the accumulation of fruits and seeds which are part of the allochthonous input in this habitat.

 

Substrates would likely be a mix of finer sands, and you could include some of the more nutritive fertilizer additives and substrates as well. These would both functionally and aesthetically represent the sediments which comprise the substrates in The Pantanal.

With aquatic plants being most common in these habitats, the rich substrates and combination of minimally-tinting botanicals makes for a most interesting planted tank! I could even see working with some marginal aquatic plants/grasses to represent the vegetation which is found in this habitat.

(Not this habitat- but an example of marginal growth...)

Although you might find some branches in this habitat, you'd likely not find big logs and such, so an aquarium attempting to replicate this habitat would likely be more realistic if you utliize twigs and smaller branches for this.

And of course, leaves could work, but I'd tend to use smaller, less "tint-capable" ones like Guava leaves if you're so inclined.

Now, we've hardly even touched on the possibilities here. Just, hopefully, whetted your appetite for this!

In the interest of keeping this blog reasonably short, I had to stay relatively superficial. And to be quite honest, I literally have no examples of an aquarium created to represent this habitat. At least, none that I am aware of, or which have permission to share photos of- so please share some if you have such a tank!  

Or, create one from scratch, and document it for us! 😍

This habitat is just FILLED with possibilities for replication!

This relative absence of representation of this habitat in the natural aquarium hobby tells me that not only is The Pantanal ripe for replication- it's a perfect ground-floor opportunity for studying, discovering, and creating evolutions and breakthroughs in the hobby.

And, with these environments under a variety of external environmental pressures, learning about, and sharing aquariums based on them- is a great way to call to attention to the threats they face. 

Time to do something, right? Let's see what you've got!

Stay inspired. Stay excited. Stay creative. Stay educated. Stay studious...

And Stay Wet.

 

Scott Fellman

Tannin Aquatics 

 

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