Natural Sources of CO2 -- ?

[dapellegrini]

I was just reflecting on natural aquascapes and realized that I have no idea how plants in a natural environment find their CO2... What produces CO2 in a lake/river?

 

[Robert H]

Plants grow above water and take it from the atmosphere. Truly submersed plants evolve to survive under very low levels of C02 derived from decaying organic matter and bacteria in the water and substrate.

 

[dapellegrini]

Really? So then would it follow that most of what we grow and cultivate in the FW planted scene will not be found in nature, the way we grow it in our CO2 injected tanks?

 

[Purrbox]

While the plants we grow are often found in nature, you aren't going to find them growing nearly as fast nor as algae free as we strive for in our tanks. We are trying to provide ideal growing conditions for plants that rarely, if ever, occur in nature.

 

[fish_4_all]

Everything that breaths gives off CO2. Fires produce it, decaying matter, car exhaust has a lot, lots of sources for it naturally. And as far as lakes and such, the simple mass of surface area allows for massive exchange amounts of CO2 into the water although the levels are about 3ppm normally. This allows the plants to use a lot more than our little tanks can provide and that is why have to inject CO2 in order to give them fastest growth. Somoene told me that so don't ask where I found it.

 

[dapellegrini]

lol...

So even if I had a good map, a snorkel and some good goggles, I wouldn't be able to find aquarium grade R. wallichii in the East Asia wild growing like I see it in photos online?

Perhaps a bad example, but I guess what I am trying to confirm is that the majority of the plants growing in my tank, specifically those that like high CO2, do not exist fully submerged in the same state in nature... Are the vast majority of the plants that we grow submerged really emersed-loving plants that we are able to adapt to full aquatic conditions with high-light and CO2 injection?

 

[rkilling1]

oh man, that's another, stay up all night on the computer, kinda night for the answer kinda question.

fish_4_all kinda answer it, at a normal rate, the plants due fine with the CO2 level found naturally in water. they have adaped to the 3PPM level by changing many things within the structure of their leaves to be able to accomplice this. (thinner membrains for better CO2 absorption, uptake nutrients from thier leaves, ect..)

that doesn't anwser your orginal question, but it should help answer why aquatic plants survive, somewhat.

we can go deeper if you would like?

HTH.

 

[dapellegrini]

LOL... you are right rkilling, this is a "stay up all night on the computer" kind of question.

My orginal question was "where does the CO2 come from..." then on realization that the CO2 simply doesn't exist in the same proportions in the natural world, the follow-up is "well is there anything natural about my aquarium?"... Thus the bit about East Asia with a snorkel... Could one truly find any of this crazy pink, red and orange flora as I am growing it, in a natural state similar to my tank? ...

I think the answer to that is coming is a NO... We make the plants much prettier by providing more of what they wish they had (or we wish they had) out in the wild.

(obivously) I am still on the lower part of the learning curve with all of this...

 

[fish_4_all]

I have seen some of our plants in pictures in nature that have the same nice colors we like to see in them. Bogs are a prime example of natural aquatic environment that can potentially have very high concentrations of CO2 in the water. Massive amounts of decaying matter that release CO2 and because of high levels of Carbonate the CO2 levels can be very high, high enough to be dangerous in the right circumstances. Ceder bogs around here in times of low rain can be fatal to most aquatic life. I have also seen the standard weed we call anacharis growing in my local lake actually become red when it got really close to the surface in low water.

The real point is your chances of walking out and seeing an aquatic plant with the same vibrant colors as we can produce in our tanks is rare and is really something you have to search out to see.

 

[Plantbrain]

There are many places nature CO2 rich water eminates from, they are called springs

Pierre water etc?

I'm sure many are familiar with soda water?

Such rivers exists in Florida, many! Same with sections of the Mato Grosso, packed with fish, turtles etc.

Shallow lakes have no issues remaining clear and algae free for the most part, the water is gin clear as long as they have about 30-50% coverage by the plants.

This is common knowledge to Limnologist that work on tropical and subtropical lakes, cough cough cough!

But old dated reference Limnology from the 1970's that was very boased towards northern lakes, of which few folks keep biotypes of, cough cough cough!

Let's bring you folks up to date by about 30 years:

Read this guy, he's been around and was at the lab I worked at for the MS:

http://fishweb.ifas.ufl.edu/Bachmann/Bachmann.htm

http://fishweb.ifas.ufl.edu/Canfield/Canfield.htm

http://fishweb.ifas.ufl.edu/Havens/Havens.htm

http://fishweb.ifas.ufl.edu/Faculty.htm

Now that group of folks and the funding for aquatic sciences and the amount of folks specifically targeting aquatic plants we actually keep and grow is enormous, far more than all the references ever supported by any aquatic plant book ever written to date.

The area of research is also specific. It examplifies the best natural conditions that one might find an aquarium tropical plant and applied research.

A lake in Demark or Minnesota that freezes every year, is very deep, has only cold water species, large turn over events 2x a year is hardly applicable to a shallow tropical planted tank don't you think?
Plants grow much faster and cycle faster at warm temps, and grow very slow at cold temps.

http://www.floridasprings.org/exploration/featured/wakulla/

There are about 90+ to chose from BTW:
http://www.floridasprings.net/

The Mato Grosso and Tx springs also host enormous amounts of optically clear waters full of plants without algae, the visibilty in the Rainbow river exceeds 200ft.

Hardly algae ridden...............

Regards,
Tom Barr

 

[Plantbrain]

Here's some examples from natural systems with clear water, I do not collect underwater that's not clear, gators eat you otherwise.

This is Ghori from the plant fest from 2004 collecting in about 15 feet deep of water and you want to see what he pulled out?

 

[rkilling1]

WOW, thanks Tom. BTW, can't wait to start reading my new subscription to the Barr report. (that's gonna take some time)

 

[Plantbrain]

I think most of the CO2 comes from ground water seepage and from the equilibration with the air above, bacteria and decomposition really produces a small amount in healthy faster growing systems, but not all.
Flowing waters have very little contribution from this source for example.
Also, wind driven lake turnover accounts for the lion's share in shallow vegetated lakes in Florida, there are perhaps dozens are well documented research articles on this subject.

Thus the air equilibrates the CO2, albeit slower than the plnts remove it during the day, the water is CO2 rich before the sun comes back up again, this the plants have access to CO2 for the first part of the monring, then about 2-4 hours in, there's none there, this is bad for the algae as well, they prefer CO2 also.

So some plants and most all algae go after the KH, the bicarbonate at this point, thus softening the water.

As the buffer is removed, the pH changes diurnally become much larger. A hardwater system is actually more productive in terms of plant growth due to the fact there is another carbon source besides CO2 available for plants and growth studies have clearly shown this effect on several plants.

 

[dapellegrini]

Thanks for the long reply Tom. I browsed through the links that you sent, though I have not had time to give them a detailed study yet.

If I am understanding correctly, you are saying that there are in fact many natural environments that are CO2 rich (i.e. natural springs), warm and chalk-full of minerals, thus perfect suited for beautiful FW plants. This answered my second question (do/can these plants in my tank exist like this in the natural world). Fish_4_all also hit this with the comment on bogs in WA.

To the initial question of "where does it come from", this is what I am understanding...

As Robert H and Fish_4_all mentioned, the most obvious source of CO2 is from organic decomposition, where your standard level is probably somewhere around 3ppm in a typical lake or river. In special eco-systems, bogs, springs, etc, the CO2 can reach much higher levels (how high???), based on a few additional factors. First is simply more organic decomposition, next would be seepage from some other ground-source (???), then wind/air exchange... Do I have it right?

So, if I did take my trusty map out into the East Asian wild, I would in fact have a chance at finding R. Wallichii growing much like the photos I see on the internet from the FW hobby... But I would need to be looking in more specialized, slow-water environments, where there is a better chance of higher CO2/KH...

I am not a Limnologist by any stretch (didn’t even know what Limnology was until today), nor do I aspire to be one, but I sure am glad there are some among us.


As an aside: that picture with the red canoe is gorgeous.

 

[fish_4_all]

Well I can't say for Florida or warm water areas but even here in the cold and right now soaked NW, there is very little algea in the water and many bodies are very clean and clear of algae all together. Every year there is an algae bloom on some lakes but that is from the turnover that brings massive amounts of nutrients up to the surface from decomposition and collecting during the winter. Once the nutrients are gone the lake goes back to clean and clear.

I didn't even think about the hot springs but when you see the springs even in Montana there is very little if any algae in them at all. Some are loaded with diatoms from the nutrient rich water from deep boiling water on lava aquafiers but no algae.

 

[Plantbrain]

D-

The springs are very stable, they have been clear and full of plants recorded back in the 1500's by Ponce De Leon's monk that came along and wrote accounts of various Florida springs. They are still full of plants 500 years later!!!!!!

So these are highly stable systems, not abberations.

So where does the original source of cO2 come from?
Ask yourself this: how are caves formed?
CO2 + water eating into limestone.

So where does the CO2 come from in spring water?

Think about rain and the soil. What happens when rain travels deep through soil?
There's aerobic bacteria in the soil(soil in terrestrial systems is full of plenty of O2, unlike flooded soils like our tank's!!!) they respire CO2 but since it's in the soil, the CO2 does not off gas to ther air above, it percolates down to the ground water rich with CO2 and becomes concentrated.

This is a different process than organic decomposition in a wetland.
It starts within a terrestrial system rich in O2, wetland soils are very very low in O2, therefore the ground water coming out of the caves is rich in CO2 and O2.
Wetland soils that are loaded with nutrients and have lots of decmopsition, by default they will have very low O2 levels. Hard for fish and many plants etc to live in anaerobic highly reducing water columns.

Some is okay, but A LOT is very bad, it depletes all the O2 in the water column.


This is why organic terrestrial soils above karst systems like Mammoth Cave have such large cave systems, the rich CO2 build up in the ground water produces this acid rich water which dissolves the limestone forming caves.

Florida is full of caves, most are underwater and are springs, many in the KY, TN, NC, VA, GA, AL, OH,IN etc all tend to be streams/dry etc or only periodically flooded. Cave diving is popular in Florida.

Regards,
Tom Barr