# PEAT LAYER IN SUBSTRATE



## faizal (11 Jun 2011)

It's often advised to include a light dusting of peat as the bottom most layer of a substrate in a non co2 set up so that there's some carbon source for the plants but we have also been equally advised not to go overboard with the peat layering as it can easily bring about other issues.

Could someone be kind enough to explain to me :

1. What these issues are.
2. What would be an acceptable range for the peat layer's thickness? 1.5- 2cm?? 

Faizal


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## ceg4048 (11 Jun 2011)

Hi Faizal,
              The issues are as follows. The addition of peat has to do with providing a carbohydrate source for the bacteria at tank startup. It has nothing to do with a carbon source for plants, which can only use carbon in the form of CO2. Later on, as the peat decays there is some release of CO2 through bacteriological breakdown, this will happen anyway from the organic waste that accumulates and which settles into the sediment from above. Too much peat or organic matter causes an excess of organic waste accumulation causing a drop in oxygen content in the sediment as the bacteria try to breakdown the waste. This can therefore have the opposite effect of causing anoxic conditions in the sediment.

The plants will adapt to the low CO2 content of the water column as long as the lighting is not excessive. CO2 from bacteriological action will occur soon enough. Since the peat addition is only there to help the bacteria in the beginning, you do not need to go over the top. Just a light sprinkling will do.

Cheers,


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## faizal (12 Jun 2011)

Thank you Clive   

I always wanted to know if the peat addition was mandatory in a non co2 set up.

My 17 Us gallon tank is still running in non co2 mode. Its currently into Day 33,...I think. The plants are settling in nicely. They look healthy,...no algae other than the occasional brown diatoms (very little amount though) on 2 occasions which went away after lightly rubbing the front glass.

It certainly isn't an aquascapers delight   ,.... but I am enjoying it nevertheless.  

 What really suprises me still is that they need so very lighting intensity to do well,....increase the lighting level a little and you start seeing some hair algae sticking out from the concerned plant and accompanied by stem melt in a few days especially with the stems ( Cabomba, Limnophila sessiliflora, Bacopa caroliniana). I was initially planning on starting co2 injection but now I am having a change of heart with this tank.

In the past,...(during my many previous short & failed attempts),...I had people telling me that the melt was due to too less lighting intensity,..one guy (an ADA local agent here) told me that the melt was due to fungal attacks,....no one had a proper scientific & acceptable explanation.

On other occasions there seemed to be voids in their explanation of things  ,...it had always been that way for me,....until I visited UKAPS.


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## ceg4048 (13 Jun 2011)

Hi mate,
             The power inherent in The Matrix is that which is our own complicity. This complicity allows the system to hide the truth from us. The bonds of our servitude are forged within our minds. I can only guess that somewhere deep in our psyche we fear the dark, so we can never voluntarily blame the light for any problem.  The wild goose chases (fungal attack??) always somehow seem more palatable than the reality.

The mechanism of CO2 failure has to do with the interactions of light, CO2 and the all important enzyme called RuBisCO.

RuBisCO is the agent that captures and transport CO2 to react with certain enzymes which strips the Carbon and combines it with Phosphate to produce a type of sugar called G3P (Glyceraldehyde Triose Phosphate). This is later converted to glucose to feed the plant cells or turned to starch for long term storage.
Now, in the image below, forget about most of the other annotations for a second. Can you see that CO2 has to diffuse through the light green Outer Membrane, through the dark green Intermembrane Space, and finally into the brown Stroma? That's a lot of work for CO2 to penetrate - and remember, that's after it has found it's way through the outer leaf surface and then through the epidermal cells. Terrestrial plants have dedicated air channels that direct the CO2 to the Chloroplast cells. Underwater, only osmotic pressure of the dissolved CO2 gets it to this location. On the other hand, can you see how easy it is for the light to get through? Billions of photons come streaming through what amounts to a thin curtain.

RuBisCO attracts and holds the CO2 (along with RuBP) and transports the pair to a location in the cell where The Calvin Cycle takes place.










Here we zoom into the Cycle. Again, a very complicated system. Just ignore everything else and check the bottom (6 O'Clock position). The produce of the Calvin Cycle is the sugar G3P. See the wheel shape? More light spins that wheel faster, meaning RuBisCO has to gather and transport more CO2 faster. Do you see the numbers preceding the various chemicals. It's a very precise cake being baked: 6 CO2 + 6 H20 and so forth. What happens if you can't produce the right number of CO2? That wheel spins right off the cart and the plant winds up in a ditch pretty quickly. More light generates faster growth so the plant has to commandeer that starch that is stored away in order to keep pace with growth. When that runs out the plant starts to cannibalize itself to find enough carbon to fuel the growth. A lot of those intermediate products we glossed over actually become toxic and do damage internally. That's another reason we see holes, deformation, discolouration, disintegration and translucency. Algae sense this immediately and attack. One way in which the plant can adapt is to produce more RuBisCO, so that it can transport more CO2 at the faster rate. But this may take a week or two. So when you hear people say "Well I turned up the light in my tank and it was OK" that's because their particular plants had stored up enough carbohydrate and nutrients to weather the transition until more RubisCo could be produced and deployed. The plant can also reduce the number or density of pigments to lower the efficiency and to protect itself from overdrive.






 

Cheers,


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## faizal (13 Jun 2011)

You are THE Morpheus indeed!!! 

Clive,...you rock dude!!!


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## CeeJay (13 Jun 2011)

Hi all

It's moments like this that remind me why I come here so often  
How can one man get so much plant information in his head? 
Great explanation, as always


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