Few years ago I had a great pleasure of discussion with Sidinei Thomaz about rivers and ecology in Brasil, he admitted that lots of measures he and his team had taken years ago were completely f..ed up and they should do many things differently - most common problems were taking measure of specific parameters only one or two times per year, other ones were taking specific samples only in one place instead of may places (for the same river/ basin). All because of the low budget, lack of time etc. So we should bear in mind that lots of numbers we read may be quite skewed or at least averaged, completely changing the whole picture.
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Long term effects of co2 exposure
- Thread starter Soilwork
- Start date
There are these threads as well
Are co2 enriched tanks really fair on the critters?
Although the title may sound like I am trying to make a point. This really is intended as a question. Are users aware of a studies, articles or even experiences that shed light on potencial long term affects on fauna of living in co2 enriched enviroments. I ask because hearing of fish struggling...
www.ukaps.org
Does CO2 injection cause disease? Thoughts?
Hi All, Just read a blog from Nathan Hill. What are your thoughts / take on this? http://www.practicalfishkeeping.co.uk/content.php?sid=6769
www.ukaps.org
Wookii
Member
Does it say how the CO2 is calculated? Surely they haven't just used the measured KH and pH and then used the tables to determine the CO2 level - as scientists they'd surely know to look at the pH difference from a degassed sample as we do in a tank for pH profiling?
There is no mention on how it's calculated. I will tag @Christel although she hasn't been active in the forum for close to a year.
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Hi all,
You would need to use a specialist dissolved CO2 meter and probe for direct measurement in the field and <"they aren't cheap">. I've never actually seen one, although I know they exist. The Oxyguard one linked is ~$4000.
This is the reason they aren't cheap and people use pH drop, or a drop checker, to estimate CO2 value.
cheers Darrel
I'd guess they probably did, because it says "CO2 calculated." and some of those are pretty unlikely values. It might have been by titration, but you would still have to assume all the the acidity was from dissolved CO2.
You would need to use a specialist dissolved CO2 meter and probe for direct measurement in the field and <"they aren't cheap">. I've never actually seen one, although I know they exist. The Oxyguard one linked is ~$4000.
This is the reason they aren't cheap and people use pH drop, or a drop checker, to estimate CO2 value.
You can see that the principle is actually similar to the drop checker in that only CO2 diffuses through the silicone membrane (and across the drop checkers air gap).
cheers Darrel
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Some values are just insanely high. 109 ppm in a habitat in Sarawak Borneo.
Hi all,
If you look at the Rio Roseira, the conductivity was 16 microS, alkalinity 0.4 dKH and pH 5.6. So we are in a, pretty much, pure water situation with very few ions of any description.
At atmospheric CO2 levels the pH of pure H2O <"should be about pH 5.6"> (due to the small proportion of dissolved atmospheric CO2 that becomes H2CO3 and then disassociates into a proton H+ and HCO3- ions and acids are <"proton donors">) and there would have been ~400 ppm atmospheric CO2.
We don't have many ions of any description, even if they are all HCO3- ions, but the quoted CO2 level is 49.5 ppm. At that point the pH should have been about pH2, because pH is a ratio and we don't have (m)any bases "proton acceptors" to balance the added protons and <"stop the pH plummeting">.
cheers Darrel
Something is definitely wrong there. I've never seen a <"theoretical dKH ~ CO2 ~ pH chart"> that goes below pH6, but I can't see the chart will work at below the level of dKH that would raise the <"pH to the equilibrium value">.
If you look at the Rio Roseira, the conductivity was 16 microS, alkalinity 0.4 dKH and pH 5.6. So we are in a, pretty much, pure water situation with very few ions of any description.
At atmospheric CO2 levels the pH of pure H2O <"should be about pH 5.6"> (due to the small proportion of dissolved atmospheric CO2 that becomes H2CO3 and then disassociates into a proton H+ and HCO3- ions and acids are <"proton donors">) and there would have been ~400 ppm atmospheric CO2.
We don't have many ions of any description, even if they are all HCO3- ions, but the quoted CO2 level is 49.5 ppm. At that point the pH should have been about pH2, because pH is a ratio and we don't have (m)any bases "proton acceptors" to balance the added protons and <"stop the pH plummeting">.
cheers Darrel
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Im glad Hanuman brought it up, because this is exactly the issue with the "natural CO2 measurements" we are trying to base our practices on. If this method is not acceptable for calculating CO2 in our tanks, why would we accept this way of calculating CO2 in the field.
We would all like to know what the fish are actually used to, but im not convinced that those numbers are "it".
We would all like to know what the fish are actually used to, but im not convinced that those numbers are "it".
_Maq_
Member
I think these numbers don't fit together. If there were "nothing" in the water but bicarbonates, it'd return 8.7 mg/l TDS ... and only 16 µS/cm EC???? To me it seems highly unlikely.
hypnogogia
Member
No, i don’t think she has as I checked some of the CO2 levels on her tables against ph/kh tables and the CO2 values differ.
Soilwork
Member
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I was under the impression we got the 30ppm co2 from EI? What was T.Barrs reasoning for the 30ppm co2?
I doubt it though. What I think is that most of these figures where taken by different people at different times under different conditions. Co2 is said to be calculated but even the dKH/PH chart doesn't seem to match these values so I have no clue how the people came up with these figures, but they seem off by a large degree. It would be good if Christel could comment since it's her book but I guess most of the figures were compiled by multiple scientists, not her alone. I'll send her an email see if she can chime in.
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Andy Pierce
Member
I thought 30ppm was empirically determined: as high as you can go with no signs of stress in the livestock. I think you can actually push the CO2 to 45ppm or higher without obvious acute distress, but 30ppm gives plants a big enough boost such that going to higher CO2 doesn't give enough gain to the plants to offset the increased risk to livestock.
Hi all,
cheers Darrel
I'm busy today, but when I've got time I'll see what I can find in the scientific literature. I think it is just a slightly different chart to the one @_Maq_ posted.
cheers Darrel
Soilwork
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Yes, I thought that thats how it was determined. Under whatever crazy high light was used for EI. The plants used the figures of nutrients we typically quote for EI and the optimum level of co2 for both plant gains and fish health was set at 30ppm.
_Maq_
Member
I think you expend too much attention and effort to those incomplete data. Par example, 49.5 mg/l CO2 is quite possible if there's an underground source of water nearby. Do we know whether this is the case? Do we know the level of organic pollution of that locality? Do we know that any fish or plants were able to live at that particular locality?
Soilwork
Member
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Well we know that most aquarium species can live at 30ppm or slightly higher or we would have had user reports of such deaths. It’s going to be an unknown I guess. How long is the average high tech tank kept running in order to evaluate?
We also know that many people breathe an air like this (think of it as of additional amount of CO2 injected into balanced water environment):
while others breathe an air like this (think of it as a water with naturally balanced amount of CO2) :
Do people living in conditions like on the 1st image die immediately? Certainly not.
Are they more healthy than people living in the conditions like on the 2nd image? Well... some may argue that there's no difference. It's mostly those who are causing dirty air or scientists paid by them to prove that everything is ok.
And yes, water constantly saturated with 30ppm of CO2 is way above average, let's round average to 10ppm so we have 200% more.
