How often do you think about the substrate in your aquariums?
I mean, if you're into a planted aquarium, you probably give it a lot more thought and consideration than say, a typical hobbyist. The rest of us tend to not give the substrate much thought after we select the material we're going use...sort of "set it and forget it." However, with the resurgence of interest in biotope aquariums, we see more and more interest in substrate materials to represent the materials found in natural environments.
If you've perused our site, you've no doubt noticed that we offer a variety of botanical materials and packages to help simulate the natural materials that accumulate at the bottoms of rivers, streams, lakes, and other water courses.
These materials are a very dynamic part of the environment, shifting, accumulating, decomposing, and enriching their surroundings in a most natural way- including helping to foster the "blackwater" that we love so much around here!
However, what about what's underneath? Yeah, the actual BOTTOM of these aquatic environments? While not as variable or ever-changing as the botanical stuff, the sands, gravels, pebbles, and other materials that comprise the "hard bottom" of these environments are interesting, surprisingly dynamic, and can foster an aesthetic that can really make your aquarium come alive!
First off, consider natural waters and the impact of the substrate. In rivers, such as the Amazon, Rio Xingu, or Orinoco, you'll find materials that originate in the mountains and highlands, and gradually work their way downstream, influencing the aquatic environment chemically, physically, and geographically.
The materials are influenced by the currents and water movement, tend to "sort themselves out", and re-organize over time. To simulate this dynamic, it pays to do a little research on the specific environment that you're looking to replicate. Some parts of the Amazon, for example, are replete with larger particles of material, wit ha covering of fine sand.
Studies have shown that particle sizes tend to decrease the further downstream from the source they are found. Large rivers, such as the Amazon, have beds of shifting sands, slowly transported with the currents. Typically, the larger the item (pebble, rock, or boulder, the longer it tends to stay in one place. So, in a more powerful flow, you're more likely to find larger-sized materials.
The first recorded observations of bed material of the Amazon River were made in 1843 by Lt William Lewis Herndon of the US Navy, when he travelled the river from its headwaters to its mouth, sounding its depths, and noting the nature of particles caught in a heavy grease smeared to the bottom of his sounding weight. He reported the bed material of the river to be mostly sand and fine gravel. Oltman and Ames took samples at a few locations in 1963 and 1964, and reported the bed material at Óbidos, Brazil, to be fine sands, with median diameters ranging from 0.15 to 0.25 mm.
There is a LOT to the science of naturally "graded" materials, and you'll have to do some research on the subject. In the end, science can tell you a lot; however, creativity and your aesthetic taste are typically the "guidelines" that you'll embrace to assemble your "slice of the bottom."
With an abundance of commercially-available substrate materials on the market, it's easier than ever to replicate cool little segments of the environment. Take a sort of 'holistic" approach to constructing the substrate in your aquarium. Look into the practical and aesthetic aspects of your materials, and how you'd combine the permanent materials (gravels, sands, pebbles, etc.) with the more "transient" materials (i.e.; botanicals and leaves). It's a lot of fun, very engaging, and can almost create a "hobby within a hobby!"
So, we've barely scratched the surface of the very bottom...However, I hope that I've helped click on the lightbulb in your head to consider that what goes on "down there" is every bit as important as any other part of the aquarium! There is plenty of scholarly research out there to draw on for inspiration and information to help you divide a plan.
Get to it!
Stay excited. Share what you've learned.
And stay wet.