Maq's experiment 23b

[dw1305]

Hi all,

I think we both have the same view about what is really important , and that is maintaining a high <"level of dissolved oxygen">.

This paper has just come my way. It isn't entirely relevant to all of us (but would be to pond keepers). <"Dissolved oxygen concentrations affect the function but not the relative abundance of nitrifying bacterial populations in full-scale municipal wastewater treatment bioreactors during cold weather - PubMed">.

......... The relative abundance of nitrifying bacteria was determined by sequencing of PCR-amplified 16S rRNA gene fragments. In the three bioreactors with low DO concentrations, effluent ammonia concentrations sharply increased with a decline in temperature below approximately 17 °C, while the bioreactors with high DO concentrations showed stable nitrification regardless of temperature. ...........

....... The relative abundance of nitrifying bacteria was determined by sequencing of PCR-amplified 16S rRNA gene fragments.....Even with the decline in nitrification during the winter in the three low DO bioreactors, the relative abundance of ammonia oxidizing bacteria (mostly Nitrosomonas spp.) was curiously maintained. The relative abundance of nitrite oxidizing bacteria was similarly maintained, although there were substantial seasonal fluctuations in the relative abundance values of Nitrospira spp. versus Nitrotoga spp. This research suggests that nitrification activity can be controlled during the winter via DO to produce better effluent quality with high DO concentrations or to reduce aeration costs

I'm going to say that the microbial 16S rRNA assay wouldn't differentiate between nitrifying Bacteria and Archaea because it is a mitochondrial gene <"16S ribosomal RNA - Wikipedia"> and occurs in both domains? Some-one who knows more about microbiology might be able to comment?

cheers Darrel

 

[eminor]

Definitely so, but I'll happily leave this research to others.
I'd rather not discuss my objections to CO2 injection in the public.

Wish i could be able to think like that about co2, I'm a junky now, once you get co2, it's hard to get off

 

[DudeFromPantanal]

I welcome your criticism, it's stimulating.
My assessment that high phosphates hinder iron uptake is not based solely on this experiment. Precipitation of FePO4 is well documented in environmental literature. Also, many hobbyists have observed brownish powder on the bottoms of their canister filters. Reversely, iron oxides are used to remove phosphates from water.
In fact, I'm permanently adjusting my dosing of phosphates and iron to avoid losses and insufficiency of either of them. Most of my tanks are firmly in acidic realm, and yet multiple times I've observed issues with both of them which likely were attributable to their interactions.

@_Maq_ I do agree with you on this. A little sidetrack question for you… have you run low nitrates ow low N planted tanks? and what about low or limiting P in a tank? i have noticed less problems with lower P in a tank and with an extra attention to ratios. But I don’t find out yeat if low P also renders more and better colors in plants (like N limitation)? Also, how low could I go with P without renders it useless by precipitation/combination with other nutrients and if not losing it chemically, going low enough to make stem plants rot in the bottom and detach from substrates, for example?

 

[_Maq_]

But I don’t find out yeat if low P also renders more and better colors in plants (like N limitation)?

I think not. In my experience, lack of P manifests itself in creating smaller leaves and weaker shape in general, followed by dying-off.

Also, how low could I go with P without renders it useless by precipitation/combination with other nutrients and if not losing it chemically, going low enough to make stem plants rot in the bottom and detach from substrates, for example?

If I understand correctly, you want to know what is the minimum level of P in the water column to avoid death. In short, I don't know. I imagine that only part of phosphorus we dose for our plants is actually consumed by them while in the water column. A significant part is consumed by microbes, largely within the substrate. Such a phosphorus then enters re-cycling processes and is taken up by plants' roots. So, in theory (and quite likely in practice) the water column may be completely devoid of any phosphates and plants can still thrive.
Just by chance, right now I've been running an experiment in mature tanks. I've ceased fertilizing completely over two months ago. The plants still grow and display no signs of deficiency. The substrate was just plain silica sand 18 months ago, but since then, remarkable amount of dead and living organic matter has accumulated in it. It seems that it's capable of full nutrition for the plants for quite a long time. (Of course, these are low-tech tanks, as always with me!) The water column conductivity is about 20 to 30 µS/cm.

 

[DudeFromPantanal]

I think not. In my experience, lack of P manifests itself in creating smaller leaves and weaker shape in general, followed by dying-off.

If I understand correctly, you want to know what is the minimum level of P in the water column to avoid death. In short, I don't know. I imagine that only part of phosphorus we dose for our plants is actually consumed by them while in the water column. A significant part is consumed by microbes, largely within the substrate. Such a phosphorus then enters re-cycling processes and it taken up by plants' roots. So, in theory (and quite lilkely in practice) the water column may be completely devoid of any phosphates and plants can still thrive.
Just by chance, right now I've been running an experiment in mature tanks. I've ceased fertilizing completely over two months ago. The plants still grow and display no signs of deficiency. The substrate was just plain silica sand 18 months ago, but since then, remarkable amount of dead and living organic matter has accumulated in it. It seems that it's capable of full nutrition for the plants for quite a long time. (Of course, these are low-tech tanks, as always with me!) The water column conductivity is about 20 to 30 µS/cm.

Interesting. Now I run around 0.5 to 0.9ppm total P per week. At 0.010 - 0.030ppm P the stem plants bush started to detach from the substrate, but I notice this problem on time. Now I wonder if I should go up this level of P even more or just stay around 1ppm per week. Will drop a link to the video I made of the tank a day or two ago (to the youtube):

Btw: my plants are easy plants.

 

[_Maq_]

I like your tank, @DudeFromPantanal . It strikes me as intelligent.

 

[DudeFromPantanal]

I like your tank, @DudeFromPantanal . It strikes me as intelligent.

TEAM SAND HERE! KKK
thanks

 

[Indianjunkie]

The HCo3 levels were kept higher in all the experiments. High KH is known to stunt plant growth. Fluctuating KH values are known to negatively affect stem plants growth as well. It would have been better to see EI level of dosing with low KH in the experimental tanks.

 

[_Maq_]

The HCo3 levels were kept higher in all the experiments.

I deliberately add no bicarbonates.
In general, I agree that bicarbonates may present difficulty. The evidence of their negative effects in aquarium conditions is ambiguous, though. Many hobbyists seem to overcome this issue with CO2 injection.

It would have been better to see EI level of dosing with low KH in the experimental tanks.

I disagree. EI is defined as "providing as much of all nutrients as not one of them ever gets short". If all tanks were oversupplied with nutrients, then I'm in difficulty to tell what I should expect. On the other hand, if some are richly supplied (B and C), while the others feature very modest amount of nutrients, then the conditions are contrasting and we can observe what difference it makes.
Still, if you develop your idea further and bring good arguments, I may change my mind.

 

[PARAGUAY]

As I understand it Tom Barr s approach essential nutrients "luxury uptake" was for CO2 injected aquariums were plants needed nutrients for fastter demand growth. The reason Green Aqua sell EI fertiliser but use ADA lean fertilisers in their showroom is for maintenance reasons, but have rich mainly substrates so uptake and growth is slower but healthy.
In an interview John Whelan APFUK said using EI for low non CO2 would be difficult and not recommended
Think it would cause issues in a test like @_Maq_ is doing

 

[aquanoobie]

Marschner provides an ideal ratio

Hi
What makes his ratio ideal?
Thanks