Substrate in Nature

[Streetwise]

I have been thinking a lot about how substrate exists in nature, especially with gravel vs sand. My hobby context is with organic soil underneath, where I prefer gravel as a cap, but I don’t want to be too specific.

I grew up on Lake Champlain, which has some of the oldest former reefs in the world, from when it was the Champlain Sea. However, there are very few sandy beaches on the lake. The two big ones are Sandbar State Park on the Vermont side, fed by the Lamoille River, and Ausable Point on the New York side, both cases where the rivers have been depositing sand for millennia.

In the marine environment, we expect tons of flow, grinding down rocks and coral. Freshwater seems to have more conditions.

[Guppysnail]

I do not do sand in tanks but what I have observed where sand is there is little plant life. It almost seems like it would choke the plants maybe? Silt and mud is where I find plants flourish. There are usually rocks mixed in to give weight to it for plants to anchor.  When we are out at lakes rivers streams etc. I find the best harvest of plants in the muddiest medium/ smallish size rock areas. 

[Streetwise]

@Guppysnail, I agree that sand can choke substrate and roots because of its density. It needs flow or turnover. I collected the largest Bacopa I have seen from a local rocky environment.

[GardenStateGoldfish]

On 8/18/2021 at 5:59 PM, Guppysnail said:

I do not do sand in tanks but what I have observed where sand is there is little plant life. It almost seems like it would choke the plants maybe?

This may depend on the type of sand or the water quality? I have natural beach sand in all of my tanks but one (which the other has store purchased sand) and plants do excellent in it. I have no experienced any plants choking out and have to frequent cut plants back, I can show you the photos when I get home from work if you want to see it for yourself. 

All of my tanks are heavily planted, but I do keep Malaysian trumpet snails, well tons of types of snails, in every tank. So maybe that is why my experience with sand is what it is because they churn it, I also have all the tanks but one as goldfish tanks, so they also churn the sand so maybe that is the key difference.  

[Daniel]

I have collected maybe a dozen species of aquarium plant in the wild, and except for the floating ones like hornwort, all were rooted in 'muck'. I prefer sand for its aesthetic qualities, but at the least in wild most plants seems prefer gooey, slimy, greasy muck.

[Streetwise]

@Daniel, I also love the muck, mulm, and mess of local slow water. What is the typical geology of the waterways in your region? I know it is part of the the same Appalachian range we have in Vermont, but so many factors have shaped the ecology and geography.

[Patrick_G]

Chris Lukhaup’s video in the Rio Brava. One of the few ecosystems that looks like an aquascaped tank with “clean” substrate. Absolutely Amazing! 

 

[GardenStateGoldfish]

On 8/18/2021 at 8:13 PM, Streetwise said:

I also love the muck, mulm, and mess of local slow water.

I read a study when I was supposed to be school work in the schools database (oops) on water flow and plant and fish growth, they found the slower the water the quicker the growth, it was pretty interesting, I found the link to the article but it is behind a paywall. 

[Guppysnail]

@GardenStateGoldfish very curious did the article say why? Maybe caloric expenditure to fight current for fish or erosion for plants or something of that nature?

[Streetwise]

@GardenStateGoldfish, and @Guppysnail, I would guess that slower flow collects more soil, and makes life easier for plants.

In contrast, the big Bacopa that I collected was probably fed by wind flow oscillations, water treatment output, and the Laplatte river supplying the bay. It only had rocks as substrate, but it had the largest root system that I have seen in aquatic plants besides mangroves. I haven't really seen a hobby tank like it, but I could describe it if someone with a 120+ would like to try. There was no dirt, sand, or gravel.

I did not keep anything long-term, for fear of Zebra mussels.

[Water Box Dreams]

I have seen flowing natural rivers in the wild that look just like popular aquarium aquascapes, river pebbles of various grades from large rocks to medium size pebbles to a fine grade of gravel (2mm) not sand, all mixed together, but not an underwater plant to be seen except algae clinging to rocks. The Hunter River, West of Newcastle NSW comes to mind. No plants but it is very beautiful.

Edited August 19, 2021 by Water Box Dreams

[Patrick_G]

The mountain rivers of the western US are the same way. Beautiful crystal clear water, but the only true aquatic plants are in the slow side channels and back eddies. 

[Gator]

@StreetwiseHere in WV, we have several rivers similar to the western rivers; fast flowing, lots of rocks, waterfalls, class 4, 5, and 6 rapids, though I think a class 6 rapid actually is a waterfall, but what do I know?

In the Spring when we have rain and snowmelt, the rivers are muddy, visibility about 1/4 inch, if that much. That mud collects along the banks of these rivers to form sandbars, mud flats, and islands. In these places where the water flow is slower, an invasive species of aquarium plant grows called Hydrilla, but it doesn't grow out in the main channel..

I go down to the New River from time to time to pick up rocks that I think may look good in one of my tanks. It was on one of these forays that I picked up a piece of Quartz that has a gold vein in it, pretty cool.

There is a lake near here that is a great place (for WV) to fish with some large Bass, Bluegill, and Crappie in it because of all of the aquatic vegetation in it. Thankfully there is no Hydrilla in it, but there is Eurasian Milfoil, Hornwort, and Dollar Lilies.

It is said that the New River that runs through here is the oldest river in the US, but ironically, the New River changes names 3 times to the Kanawha, the Ohio, and the Mississippi before it reaches the Gulf of Mexico. Go figure, right? 

[Jungle Fan]

With too much flow, you get less accumulation of debris, the less debris, the less decomposition the less decomposition, the less nutrients for new growth. When I used to go snorkeling different rivers and creeks in the Southeast, and South, the most amazing plants were generally located in slower moving waters, and yes there was the muck, and slime. The one exception was Florida where there were some creeks and rivers that looked like aquascapes but did not have as much muck on the bottom but even there the closer you got to the edge of the water the mulm/muck was  present, and that's generally where the majority of plants were. By the way it is always a good idea to have others with you going snorkeling in that region because of alligators, and snakes.

[Patrick_G]

@Jungle Fan, I’ve experienced some clear water planted areas too. The most memorable are the Cenotes in the Yucatán and a beautiful surprise of a spring feed lake in southern Oregon. Both have a rich looking substrate.