II think we can't talk too much about how the physical structures of aquatic habitats influence well- EVERYTHING! I mean, water flows through all sorts of submerged physical structures, ranging from tree trunks to leaf litter assemblages- and that has a huge physiological-chemical influence on the habitat overall as well.
It's very easy to overlook this simple fact in our quest to create cool-looking tanks!
You could take your aquarium design vis-a-vis hardscape further and manipulate water flow patterns and such to allow botanical materials to accumulate in certain areas, or allow stands of certain types of plants to grow in specific locations within the aquarium. Understanding (or at least, observing) how physical barriers, like wood and rocks are oriented by water currents, local geology, and even weather, and also impact the movement of water in a given area, could help you create some interesting scapes.
Lately, it's been all the rage among competitive 'scapers to "break the waterline" with wood. And it's cool. I like it. It has a neat look. Yet, I have to admit, albeit a bit sheepishly- that after seeing several hundred pics of tanks with driftwood heading out of the water (and having done some myself), I can't help but think it's become too much of a "formula": "Assemble group of rare aquascaping rocks, insert manzanita branches in vertical orientation with respect to 'Golden Ratio' and break water line. Done."
Or I Might even say, "vomit"...'cause you know I won't hold back on how I feel about this stuff. How can we save this from becoming another "Scott-hates-the-'social-media- aquascaping-world'-and-sounds-like -an-asshole" rant?
What about approaching this from the standpoint of how and why this would happen in Nature?
I mean, ask yourself under what circumstances would a piece of wood break the waterline? If you study streams and other bodies of water, the reasons are relatively few, but fairly apparent. Likely, one of a few scenarios: 1) A big branch falls into shallow water, with part of it sticking up out of the water. 2) A fallen branch, limb, trunk, or entire tree is covered by water when seasonal inundation submerges the forest floor 3) A tree or shrub growing along an actively-flowing river or stream becomes partially submerged by a large seasonal influx of rain or tidal increase.
It's the same for rocks, and the distribution of substrate materials, botanicals, and leaves. If we ask ourselves how and why these materials accumulate the way they do in nature, the answers create many interesting and inspiring situations for aquascaping. Making the study of natural structures in aquatic habitats part of our inspiration "lookbook" and incorporating them into our "tradecraft" has, IMHO, always yielded more interesting, long term functional aquariums.
In addition to these purely artistic interpretations, (which are beautiful for the most part-I'll give you that) even more amazing, more functionally aesthetic and realistic aquariums can be created by simply looking at what caused these habitats to form in nature, and assembling and placing the components you're using based upon that.
The idea of simulating fallen tree trunks and logs and branches in aquariums is as old as the art of aquarium keeping itself. However, I think the approach of looking at them not just as "set pieces"- but as the foundational cornerstone of a biological and physical habitat gives new context to the practice. Rather than just, "Woah, that peice of wood is a great place for my cichlids to hide!", perhaps we could think about how the wood provides foraging or a corralling feature for leaf litter, soil, etc.
Everything from driftwood to twigs to roots has an important place in simulating the function and look fo the aquatic habitats we love so much. Simply looking at this stuff from a purely aesthetic standpoint sell it short, IMHO.
Combinations of these materials (contained in various ways) could create an interesting functional AND aesthetic terrestrial component that could influence the water chemistry and ecological diversity of our systems.
Asalways, the big opportunity here is not only to create a realistic, compelling display- it's to further unlock some of the secrets of nature and study the interactions between land and water. It's about incorporating function into our displays, and appreciating the aesthetics which accompany it!
Stay inspired. Stay creative. Stay observant. Stay diligent. Stay open-minded...
And Stay Wet.