TbyZ
Well-Known Member
I have noticed quite a few threads here concerning people having trouble with algae of various types growing in displays.
Thinking about carbon dosing & deep sand beds, nitrification & denitfification, live rock & porous imitation rock, I hope the following may help some hobbists having algae issues.
The following extract is from an article by Bob Goemans. It specifically concerns deep sand beds, thus nitrification & de-nitrification, & of course carbon dosing is all about turbocharging this bacterial process.
Quote - “The resulting nitrate is then acted upon in a lower area of the substrate (sand or rock) that contains little or no oxygen, generally referred to as the anaerobic area. And it is there we found two different classes of bacteria going two different paths; one reducing nitrate to only that of ammonium (the primary alga nutrient), and the other reducing it to nitrogen gas. This caused us to question the long standing aquarist understanding of the denitrification process, as I and many other aquarists always thought that with nitrate being an alga encouraging nutrient and/or water quality issue, its reduction in ‘so-called’ anaerobic areas would ‘always’ result in it being reduced to nitrogen gas and harmlessly dissipating upwards through the substrate and water column.
But what we found was that a far more important nutrient to algae than nitrate, i.e., ammonium, was being produced in this ‘anaerobic’ area. And this ammonium could diffuse upward in the substrate/sediment and enter the bulk water or again simply be oxidized back into nitrite/nitrate, which may also diffuse upward into the bulk water! Therefore, it became necessary to look more closely at what was called the ‘anaerobic’ area and define the logistics associated with its bacterium.
Further research showed that facultative anaerobic heterotrophs live in an area that contain a small amount of oxygen, i.e., approximately 0.5 - 2.0 mg/l (per Sam Gamble and defined in our previous writings as the ‘anoxic’ area). They generate dissimilatory denitrification where nitrate is reduced to its basic elemental form — nitrogen gas. In an area of less oxygen content, more precisely called the anaerobic area, obligate anaerobic heterotrophs existed and the ‘end result’ of their process, technically called assimilatory denitrification, is ammonium. This is generally referred to as the ammonification process. And a continuing reprocessing of this ammonium in the lower ‘anaerobic’ level of the substrate back into nitrite/nitrate in the upper reaches of the substrate is quite feasible, with any of them, i.e., ammonium, nitrite, nitrate, possibly leaching back into the bulk water!”
http://www.saltcorner.com/Articles/Showarticle.php?articleID=117
========================================================
Further;
Nitrate and Phosphate Reduction via Carbon Dosing
Published: 27.09.2013
it is important to be aware that the dissimilation processes in the marine environment involves very complicated ecological interactions between several groups of bacteria. These groups include 2 groups of dissimilatory nitrate reducers
the first group is the DNRA bacteria that reduces nitrate to either nitrite or ammonia, and the other group of heterotrophic denitrifiers that reduces nitrate via nitrite to gaseous nitrogen. Elemental nitrogen is the end product of this process, but intermediate accumulation of nitrite, nitric oxide and nitrous oxide may take place under certain conditions
Environmental factors, in particular the availability and type of organic carbon compounds, the C/N ratio, the availability of specific co-factors and the oxidation/reduction state of the aquatic environment, dictate to a large extent the occurrence of each dissimilatory group and the primary reduction pathway.
For example; an unbalanced C/N ratio will prevent full denitrification and will increase DNRA activity which leads to the accumulation of ammonia and nitrite. After the initial maturation cycle most hobbyist do not test for NH4+ and NO2– and therefore while dosing carbon sources they may observe a reduction in NO3– but will not notice any accumulation of ammonia or nitrite. Even when the C/N ratio is optimal for denitrification there are other obligatory factors that regulate the full denitrification of nitrate to free nitrogen.
These factors include specific chemical elements that act as co-factors in each stage of the denitrification process. The absence or unbalanced levels of these elements may end the denitrification process in any of the early stages and will lead to the accumulation of toxic N2O and NO.
http://www.redseafish.com/blog/nitrate-phosphate-reduction-via-carbon-dosing/
Thinking about carbon dosing & deep sand beds, nitrification & denitfification, live rock & porous imitation rock, I hope the following may help some hobbists having algae issues.
The following extract is from an article by Bob Goemans. It specifically concerns deep sand beds, thus nitrification & de-nitrification, & of course carbon dosing is all about turbocharging this bacterial process.
Quote - “The resulting nitrate is then acted upon in a lower area of the substrate (sand or rock) that contains little or no oxygen, generally referred to as the anaerobic area. And it is there we found two different classes of bacteria going two different paths; one reducing nitrate to only that of ammonium (the primary alga nutrient), and the other reducing it to nitrogen gas. This caused us to question the long standing aquarist understanding of the denitrification process, as I and many other aquarists always thought that with nitrate being an alga encouraging nutrient and/or water quality issue, its reduction in ‘so-called’ anaerobic areas would ‘always’ result in it being reduced to nitrogen gas and harmlessly dissipating upwards through the substrate and water column.
But what we found was that a far more important nutrient to algae than nitrate, i.e., ammonium, was being produced in this ‘anaerobic’ area. And this ammonium could diffuse upward in the substrate/sediment and enter the bulk water or again simply be oxidized back into nitrite/nitrate, which may also diffuse upward into the bulk water! Therefore, it became necessary to look more closely at what was called the ‘anaerobic’ area and define the logistics associated with its bacterium.
Further research showed that facultative anaerobic heterotrophs live in an area that contain a small amount of oxygen, i.e., approximately 0.5 - 2.0 mg/l (per Sam Gamble and defined in our previous writings as the ‘anoxic’ area). They generate dissimilatory denitrification where nitrate is reduced to its basic elemental form — nitrogen gas. In an area of less oxygen content, more precisely called the anaerobic area, obligate anaerobic heterotrophs existed and the ‘end result’ of their process, technically called assimilatory denitrification, is ammonium. This is generally referred to as the ammonification process. And a continuing reprocessing of this ammonium in the lower ‘anaerobic’ level of the substrate back into nitrite/nitrate in the upper reaches of the substrate is quite feasible, with any of them, i.e., ammonium, nitrite, nitrate, possibly leaching back into the bulk water!”
http://www.saltcorner.com/Articles/Showarticle.php?articleID=117
========================================================
Further;
Nitrate and Phosphate Reduction via Carbon Dosing
Published: 27.09.2013
it is important to be aware that the dissimilation processes in the marine environment involves very complicated ecological interactions between several groups of bacteria. These groups include 2 groups of dissimilatory nitrate reducers
the first group is the DNRA bacteria that reduces nitrate to either nitrite or ammonia, and the other group of heterotrophic denitrifiers that reduces nitrate via nitrite to gaseous nitrogen. Elemental nitrogen is the end product of this process, but intermediate accumulation of nitrite, nitric oxide and nitrous oxide may take place under certain conditions
Environmental factors, in particular the availability and type of organic carbon compounds, the C/N ratio, the availability of specific co-factors and the oxidation/reduction state of the aquatic environment, dictate to a large extent the occurrence of each dissimilatory group and the primary reduction pathway.
For example; an unbalanced C/N ratio will prevent full denitrification and will increase DNRA activity which leads to the accumulation of ammonia and nitrite. After the initial maturation cycle most hobbyist do not test for NH4+ and NO2– and therefore while dosing carbon sources they may observe a reduction in NO3– but will not notice any accumulation of ammonia or nitrite. Even when the C/N ratio is optimal for denitrification there are other obligatory factors that regulate the full denitrification of nitrate to free nitrogen.
These factors include specific chemical elements that act as co-factors in each stage of the denitrification process. The absence or unbalanced levels of these elements may end the denitrification process in any of the early stages and will lead to the accumulation of toxic N2O and NO.
http://www.redseafish.com/blog/nitrate-phosphate-reduction-via-carbon-dosing/
