New Nitrate theory
- Thread starter Paul B
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Joe Pusdesris
New member
I do not know much about biology but some googling shows that Azotobacter is a bacteria that lives in aerobic conditions and can fix nitrogen in soil. I do not know if this bacteria can survive in marine conditions or if it is the same bacteria genus as is what was discussed in this thread. But it is a non-cyano example nonetheless.
Aquarist007
New member
I thought that oxygen, nitrogen and carbon dioxide gases, being lighter then seawater would rise to the surface and bubble off---not be a contributing factor on the surface of the dsb and definetly not a factor in the deep zones which support anoxic bacteria.?
jenglish
Marquis de Carabas
I can see this being theoretically a net gain in nitrogen, but in practical terms I don't see this happening short of having pure nitrogen gas above your aquarium. In a practical example you would have to have sufficient nitrogen fixing bacteria in the substrate to process nitrogen into ammonium. To get a net addition of nitrogen to the tank you would need these in sufficient quantitiy to process all the nitrogen put into the tank plus more dissolving. This seems unlikely to me. I can't rule this out but it seems doubtful. This would be a testable hypothesis though if someone had a established DSB and removed all critters and quit feeding it. If the nitrate levels kept rising, then this could be confirmed no?
Joe Pusdesris
New member
Oops, my mistake. Sorry everyone, the Azotobacter I found earlier lives in aerobic conditions, but there is a whole list of other bacteria that live in anaerobic conditions below, it would seem they are more productive as well.
http://en.wikipedia.org/wiki/Diazotroph
jenglish, the gas above your tank is N2. Well, mostly. Air is almost 80% nitrogen. Fun fact, that nasty CO2 in our houses that effects ph so much is only about .04% of air.
Also, those that doubt air dissolves in water, either do some reading or shake a bottle of pop, whatever you prefer.
http://en.wikipedia.org/wiki/Diazotroph
jenglish, the gas above your tank is N2. Well, mostly. Air is almost 80% nitrogen. Fun fact, that nasty CO2 in our houses that effects ph so much is only about .04% of air.
Also, those that doubt air dissolves in water, either do some reading or shake a bottle of pop, whatever you prefer.
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Thanks for the reply. Yes a non cyano example; so are chloroplasts , but azobacter sounds a lot like cyano and may have evovled from it in that it too forms anoxic cysts where athmospheric oxygen is fixed but the actual azobacter organism is aerobic so it's existence in the soil doesn't support the notion that bacteria which thrive in anoxic zones would be able to fix nitrogen.
jenglish
Marquis de Carabas
<a href=showthread.php?s=&postid=14618771#post14618771 target=_blank>Originally posted</a> by Joe Pusdesris
Oops, my mistake. Sorry everyone, the Azotobacter I found earlier lives in aerobic conditions, but there is a whole list of other bacteria that live in anaerobic conditions below, it would seem they are more productive as well.
http://en.wikipedia.org/wiki/Diazotroph
jenglish, the gas above your tank is N2. Well, mostly. Air is almost 80% nitrogen. Fun fact, that nasty CO2 in our houses that effects ph so much is only about .04% of air.
Also, those that doubt air dissolves in water, either do some reading or shake a bottle of pop, whatever you prefer.
Yes, air is at nearly 80% nitrogen but it has been shown that low oxygen bacteria can turn NO3 to nitrogen gas and gas it off into this 80%. This is how coil denitrators, DSB and large LR all work So for this absorbtion of additional nitrogen gas would to me be unlikely under normal enviromental conditions.
Shaking a pop would be more of an example of off gassing than natural absorbtion of atmospheric gasses.
Sorry , I missed your follow up post.
Thanks for the link on diazotrophs and the knowlegeable discussion.
I noted that the diazotrophs are primarily involved in symbiotic realtionships with root structures or intenstines etc.Couldn't find any listed that weren't.
Nonetheless, I guess it's possible to specualte that some non symbiotic form of nitrogen fixing anerobe(probably evolved from cyanobacteria lol) could exist in a deep substrate but none have been so identified to my knowledge. Maybe a biologist or two could chime in.
Even if non symbiotic diazotrophs did exist deep in the sand bed ,fixing athmospheric nitrogen would it seems be a challenge for them in terms of energy as you noted earlier. It also seems the alack of a carbon source would make this less likely. If decaying matter found it's way down there as the carbon source, I think it is likely that the nitrate and some oxygen might as well making it very unlikely that a net gain in organicaly bound nitrogen would result.
BTW do you happen to know if nitrogen is more or less likely to diffuse into a deep bed than oxygen or nitrate ? I don't know that but would like to..
While this speculation is very interesting I don't think it's a "new nitrate theory" and isn't a reason to ban deep sand beds as a vialbe option for denitrification in favor of plenum designs or other approaches. I still think hyrdrogen sulfide formation particulary with carbon dosing is a potential threat to the aquarium with a deep sand bed, however.
Thanks for the link on diazotrophs and the knowlegeable discussion.
I noted that the diazotrophs are primarily involved in symbiotic realtionships with root structures or intenstines etc.Couldn't find any listed that weren't.
Nonetheless, I guess it's possible to specualte that some non symbiotic form of nitrogen fixing anerobe(probably evolved from cyanobacteria lol) could exist in a deep substrate but none have been so identified to my knowledge. Maybe a biologist or two could chime in.
Even if non symbiotic diazotrophs did exist deep in the sand bed ,fixing athmospheric nitrogen would it seems be a challenge for them in terms of energy as you noted earlier. It also seems the alack of a carbon source would make this less likely. If decaying matter found it's way down there as the carbon source, I think it is likely that the nitrate and some oxygen might as well making it very unlikely that a net gain in organicaly bound nitrogen would result.
BTW do you happen to know if nitrogen is more or less likely to diffuse into a deep bed than oxygen or nitrate ? I don't know that but would like to..
While this speculation is very interesting I don't think it's a "new nitrate theory" and isn't a reason to ban deep sand beds as a vialbe option for denitrification in favor of plenum designs or other approaches. I still think hyrdrogen sulfide formation particulary with carbon dosing is a potential threat to the aquarium with a deep sand bed, however.
Joe Pusdesris
New member
N2 dissolves in seawater to a level around 20 mg/L. Quite high indeed. And with a protein skimmer or good gas exchange, I would imagine any nitrogen lost is replaced quite quickly.
Source: http://www.lenntech.com/elements-and-water/nitrogen-and-water.htm
Indeed. I have just seen far too many miserable looking tanks with shallow sand, and I haven't seen too many deep sand bed tanks that look terrible. Maybe it is because people new to the hobby tend to go with shallow sandbed, I don't know. I hope people do not start posting how their shallow sand bed looks 'fantastic.' I am judging by the % of failure, not isolated successes.
The only true problem I find with sandbeds is that they blow around. Corals do not like being covered in sand, and I like to have a lot of flow. Tanks with barebottom displays and deep sand bed refugiums seem to have the best of both worlds to me. I am not going to dig out my sandbeds any time soon.
Source: http://www.lenntech.com/elements-and-water/nitrogen-and-water.htm
Indeed. I have just seen far too many miserable looking tanks with shallow sand, and I haven't seen too many deep sand bed tanks that look terrible. Maybe it is because people new to the hobby tend to go with shallow sandbed, I don't know. I hope people do not start posting how their shallow sand bed looks 'fantastic.' I am judging by the % of failure, not isolated successes.
The only true problem I find with sandbeds is that they blow around. Corals do not like being covered in sand, and I like to have a lot of flow. Tanks with barebottom displays and deep sand bed refugiums seem to have the best of both worlds to me. I am not going to dig out my sandbeds any time soon.
Aquarist007
New member
Thank you for validating that----remote dsb's as in a refugium are the way to go. Most of my experience has been gained through participation on this site and I have found that reefers who are much more experinced in reef keeping then me seem to be opting for that setup.
IMO its easy to question the functionality of deep sand beds in our tanks when one can easily load up the biomass in their tanks, over feed that biomass and not supply enough quality live rock and macroalgae---all variables that even the best of deep sand bed setups could not reduce the amount of nitrates significantly.
Guys , I got to admit Iam somewhat confused here. I read a study that suggests a little over an inch of substrate is where nitrification and denitrification is most likely occuring.If memory serves me right most was occuring in the first couple of milimeters.(70%) the remainder 30% was found within a centimeter.
I guess I dont see the point otherwise unless someone has actual evidence that a dsb in a remote bucket,fuge or intank has more benefits that Iam unaware of ,please enlighten me.
-Graves
I guess I dont see the point otherwise unless someone has actual evidence that a dsb in a remote bucket,fuge or intank has more benefits that Iam unaware of ,please enlighten me.
-Graves
jenglish
Marquis de Carabas
I think the problem with "proving" is we would need to isolate a single independant variable, sand depth, with sufficient N for statistical significance and run multiple tanks long term. So lets wait until muy fiancee becomes my ex wife and then maybe I can do a project like that :lol:
Paul B
Premium Member
Onetrickpony, thank you for posting those sites.
I read them and also remember when those tests were performed.
I have been around to see the beginning of Berlin systems and jaubert systems.
The article you posted was interesting but was more a comparism of plenum and no plenum systems. They said there was no significant difference and I think the same thing.
Unfortunately where it comes to these laboratory tests, they were performed for (I think) 114 days which is a very new system and doesen't mean much in a tank where we want stability for years not days.
All systems will change over time. The substrates used in the tests were taken from Hawaiian waters which would differ significantly from a hobbiests tank who most likely uses ASW and does not add bacteria or nutrients from the sea. (besides me)
Also the bacterial diversity in an aquarium is severly limited compared to fresh sand from the sea.
I would like to see a test over a couple of years with ASW.
as was said in the article
Quote,
"there is far too much variability (Fig. 2) to draw any conclusions based on a single tank. We reiterate the point made by many authors before us: we need experimental rather than anecdotal evidence to draw any conclusions about the relative advantages of any particular aquarium design or additive."
This is true but it is also true that a couple of months does not prove much.
"
I read them and also remember when those tests were performed.
I have been around to see the beginning of Berlin systems and jaubert systems.
The article you posted was interesting but was more a comparism of plenum and no plenum systems. They said there was no significant difference and I think the same thing.
Unfortunately where it comes to these laboratory tests, they were performed for (I think) 114 days which is a very new system and doesen't mean much in a tank where we want stability for years not days.
All systems will change over time. The substrates used in the tests were taken from Hawaiian waters which would differ significantly from a hobbiests tank who most likely uses ASW and does not add bacteria or nutrients from the sea. (besides me)
Also the bacterial diversity in an aquarium is severly limited compared to fresh sand from the sea.
I would like to see a test over a couple of years with ASW.
as was said in the article
Quote,
"there is far too much variability (Fig. 2) to draw any conclusions based on a single tank. We reiterate the point made by many authors before us: we need experimental rather than anecdotal evidence to draw any conclusions about the relative advantages of any particular aquarium design or additive."
This is true but it is also true that a couple of months does not prove much.
"
-Paul ,I agree on the comparisons
Her is a comparison for someone with an ongoing algae out break that appaers to have the Goemans symptoms.
The usual poster will run through the testing parameters to find they all check out fine but cant explain the ongoing algae problem.
Stir up some of your substrate and test imediately afterwards for PO4 and NO3.
-Graves
Her is a comparison for someone with an ongoing algae out break that appaers to have the Goemans symptoms.
The usual poster will run through the testing parameters to find they all check out fine but cant explain the ongoing algae problem.
Stir up some of your substrate and test imediately afterwards for PO4 and NO3.
-Graves
onetrickpony
Premium Member
Paul
I would have to agree with you about time and different methods, those like you who have stayed with the hobby for many years, who have seen ideas, methods, equipment all change and stay the same. What was the new hot trend in reef keeping a couple of years ago, 5 years ago, and what will it are a few years from now. I will bet it will come down to marketing.
With everything in this hobby finding what works and what does not work will depend on who you ask. Look at the gap in knowledge between LFS and information on RC
The great thing about Reef Central and other web boards all over WWW is that there is spontaneous gathering of know age, disagreement, and questions always being asked by someone, which leads to other questions, agreements and disagreements.
The flip side to the 2 year thing is this, how many people start and leave the hobby in a 24 month period, 50% ââ"šÂ¬Ã¢â‚¬Å“ 80%
I would have to agree with you about time and different methods, those like you who have stayed with the hobby for many years, who have seen ideas, methods, equipment all change and stay the same. What was the new hot trend in reef keeping a couple of years ago, 5 years ago, and what will it are a few years from now. I will bet it will come down to marketing.
With everything in this hobby finding what works and what does not work will depend on who you ask. Look at the gap in knowledge between LFS and information on RC
The great thing about Reef Central and other web boards all over WWW is that there is spontaneous gathering of know age, disagreement, and questions always being asked by someone, which leads to other questions, agreements and disagreements.
The flip side to the 2 year thing is this, how many people start and leave the hobby in a 24 month period, 50% ââ"šÂ¬Ã¢â‚¬Å“ 80%
Aquarist007
New member
I'm amazed at the number of new members we get each day. As we know this hobby is expensive and in this economy it makes one wonder where all the money is coming from.
Maybe its the guys that got the bonus checks from AIB
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