nitrogen limitation?

[fullmonti]

Would like to hear some about this as it relates to coral heath & cyano growth. I heard a little about it & googled it but looked like a bunch of biologist round table discussions, so if you could like you are talking to a art type not biologist please.

[dan223]

Originally Posted by fullmonti

Would like to hear some about this as it relates to coral heath & cyano growth. I heard a little about it & googled it but looked like a bunch of biologist round table discussions, so if you could like you are talking to a art type not biologist please.

Simply put nitrogen is needed for plants and photosynthetic corals as these corals also utilize plants. If nitrate is too limited they starve, cyano seems to be able to handle levels lower thatn some plants like and at that point can over take them in the competition for other nutrients as they are not weakend by the lack of nitrate as much as the others. In fresh water planted tanks I have used nitrate dosing to rid cyano many times, 1 time in a reef tank also, the key is if you can read any nitrate on a test kit you are not limited IMO. It seems theres alot more to cyano and not just 1 thing that triggers it as people have it occur in tanks with higher levels of nitrate also.

[fullmonti]

OK thank you that was well put.

I retested my water just now still reads zero on my kit. I am going to take some water over to a friends house tomorrow & check it with his kit to be sure.

[HighlandReefer]

Nitrogen Control in Cyanobacteria
http://jb.asm.org/cgi/content/full/183/2/411

From this article:

"Cyanobacteria assimilate ammonium in preference to other nitrogen sources, like nitrate or N2, and utilize combined nitrogen in preference to N2. Some strains that can assimilate urea also seem to use this simple organic compound as a preferred nitrogen source."

In other words, cyanobacteria prefer to get their nitrogen source directly from fish excrement.

[fullmonti]

Thanks Cliff

What does that mean in terms of how to control cyano, can't really keep fish from poopin. I have been following your & others advice about keeping every thing clean & manual removal also got about 120 astrea snails, they seem to be doing much better than the other types that i have tried in the past.

[tmz]

Nitrogen limitation is not much of a worry in reef tanks. Levels on natural reefs are very low,less than .1ppm. In a confined aquarium achieving near or at 0 is unusual at best. There are just too many sources( food , animal waste etc.) for it.

Living things take up carbon,nitrogen and phosphorous to form living tissue. They expel excess via respiration and excretion and ultimately return them all via decay when they die.These elements are used in varying proportions by various organisms ,somewhere in the neighborhood of 116 parts carbon to 16 parts nitrogen to 1 part phosphorous. Since all 3 are used , the absence of any one of these can limit growth.


Plenty of nitrogen exist throughout the universe as nitrogen gas but most organisms can not use it until it is fixed to other atoms as they do with ammonia/ammonium(NH3/4) where it is bound to hydrogen and with nitrate(NO3) and nitrite(NO2) where the nitrogen is bound to oxygen.
Cyanobacteria and their cousins( several othe diazotrophic bacteria) have a unique ability to fix free nitrogen gas inside special anoxic(oxygen free) sacs in their structures called heterocysts. They use an enzyme which they uniquely posses called nitrogenease to do so by breaking the bond between the two nitrogen atoms in N(nitrogen gas). So while cyanobacteria thrive on available fixed nitrogen ( as well a phosphorous and carbon). They can survive without it and actually produce it.

[HighlandReefer]

Limiting nitrogen in a reef aquarium is virtually impossible. Nitrate limitation is the best way to control cyano. The only thing you can do is limit the nitrogen as best as possible (skimming, GAC, water changes, filter bags, cleaning, did I say cleaning twice). Cyano can switch from one nitrogen source to another.

This leaves working on the other factors that can help reduce cyano growth but will not eliminate them completely. These secondary factors are day-length, type of light wave frequency. Since cyano prefer their nitrogen source from fish excrement, one can limit the number of fish in their system. Also one can try things like maintaining enough nitrate to stimulate bacteria to grow better & perhaps cause the bacteria to become the dominate source for reducing the nutrients in your system. Using different carbon dosing sources may help to promote more bacterial growth also. All these secondary control methods you try have other effects on the organisms in your tank and in some cases promote more algae growth, so there is a fine line in keeping an unnatural reef system in a box.

FWIW in natural reefs algae, cyano, diatoms and other assorted organisms are present to some degree. Natural reefs don't look like the "Tank of the Month".

[Mike O'Brien]

Some strains that can assimilate urea also seem to use this simple organic compound as a preferred nitrogen source."

In other words, cyanobacteria prefer to get their nitrogen source directly from fish excrement.

Well then it's a good thing that fish don't excrete much urea. They don't work like we do. The use their gills to remove Nitrogen, mainly as Ammonia and Ammonium. They live in water, so there is never a shortage of it. Terrestrial animals produce urea or uric acid because it's less toxic to them and they need to store it in their bodies. In salt water, due to the difference of salt in the fish compared to the water, the fish needs to drink constantly, but pee very little. Again, the salt is excreted through the gills.

[Mike O'Brien]

Limiting nitrogen in a reef aquarium is virtually impossible. Nitrate limitation is the best way to control cyano. The only thing you can do is limit the nitrogen as best as possible (skimming, GAC, water changes, filter bags, cleaning, did I say cleaning twice). Cyano can switch from one nitrogen source to another.

This sounds very confusing. If cyano can utilize atmospheric Nitrogen, how can we limit it, and how can it be the best way to control cyano ?

[fullmonti]

Cliff

I think we are getting very close to the source of my confusion on that fine line of balance. I have been using zeo carbon source & zeolite reactor to cultivate bacteria & control nutrients. If I understand correctly it is very possible to cultivate too much bacteria & strip too much out of the water to the point of starving your corals, or to have too much carbon which I have learned will encourage slimes. So if this is true, what would help me immensely is to know how to recognize & Know what to do if that balance point is off. I know I've done the wrong thing at times trying to achieve that balance, but I have learned some along the way.

Mike & tmz

I have to admit much of the chemistry & interactions between all these elements does leaves me scratching my head.

[Mike O'Brien]

Would like to hear some about this as it relates to coral heath & cyano growth.

The way I think of it is simple. Different types of algae prefer different nutrient ratios. Since cyano doesn't need Nitrogen from the water, it can thrive in low N scenarios. Where there is plenty of N and also P. green algae can thrive and will often limit cyano because it's using up the nutrients first.

That said every time I had cyano it was either on an area of rock that had a lot of detritus build up on it, or on sand that had a lot of detritus built up in it. Personally I don't use sand and have a lot of water movement so detritus doesn't stick on my rock. For me that means never having to deal with cyano.

[HighlandReefer]

Mike,

There have been a lot of studies done on N limitation and its effects on cyanobacteria. Limiting the N (and not including the nitrate) does show less growth for cyano. Limiting N has a greater effect than limiting P.

This is a Google search that shows many of them:

http://scholar.google.com/scholar?q=...001&as_sdtp=on

The cyanobacteria that utilize N2 through nitrogen fixation are normally anaerobic. Certainly some cyano within bacterial masses can be anaerobic in nature. IMHO most of the cyano that we are having problems with are most likely aerobic in nature and N2 may not be as much a concern. Some cyano can change from using ammonium to N2 if the conditions are changed. The growth is much slower though. So depending on the species of cyano this will have a big impact on what is used for a N source.

I believe that most of the cyano we have problems with grow the fastest with higher ammonium levels. The research indicates that limiting ammonium may be the best way to control these species of cyano. If nothing else it will greatly slow the growth of cyano and force them to utilize the other forms of N.

Bacteria utilize ammonium too. If you remove the cyano and allow the bacteria to grow in numbers, perhaps they can take over. Hence the importance of reducing the number of fish in your system. Before I removed several larger fish from my system, I had a cyano problem. After removing some larger fish, my cyano problem petty much disappeared. Perhaps a coincidence, but the scientific facts led me to this decision.

[fullmonti]

Mike

I never had cyano at all till I killed hair algae with algaefix. It started growing on the remains I couldn't get to with tooth brush. since it started it just about took over my frag tank, but astrea snails have just about taken frag tank back.

[Mike O'Brien]

Again :

If cyano can utilize atmospheric Nitrogen, how can we limit it, and how can it be the best way to control cyano ?

And I'd say most of us are more interested in real world reef tank scenarios where most of the people with problems have already run the gamut and still have cyano present.

[Mike O'Brien]

Originally Posted by fullmonti

Mike

I never had cyano at all till I killed hair algae with algaefix. It started growing on the remains I couldn't get to with tooth brush. since it started it just about took over my frag tank, but astrea snails have just about taken frag tank back.

I think you will be fine once all that dying material is used up. I'd just keep syphoning it out as export.

[fullmonti]

I know this is little off nitrogen limitation subject, but. If your dosing carbon (only 4 drops a day in 200-250gal system) & running a zeo reactor & your tests for PO4 & NO3 both zero is that really too low? I have about 20 corals in STN I'm guessing from me doing to many things to fast. So I wonder if zero is to low & if I should feed them more, but then that also feeds algae & cyano, this is one of those times where I don't know what the right thing to do is.

If I can ever really get a grip on all this I'm sure my tank will be beautiful because I am extremely consistent & dedicated.

[Mike O'Brien]

IMO sometimes the look of the tank is more important than test kit readings. If there is algae in the tank, then there is nutrients in the water. Also algae and sps together in the same tank is a bad mix. My first step in trying to stop stn would be to get rid of the algae first.

[HighlandReefer]

Yes trying to limit nitrogen in a reef system is virtually impossible as I stated above.

FWIW, I do not have the answers to controlling cyano and many species of algae in a reef system. I have read many article about it, but these articles do not come up with a good solution that works for every hobbyist. I can only present the facts as I know them. Every little bit helps. I believe that every hobbyist's system is unique in regards to what micro-organisms are present and thus controlling cyano may be different for every tank.

It helps to know that Randy has a cyano problem and is working on using vinegar and vodka to try to control cyano in his system. With his knowledge and experience, it makes us fell better that he too has problems. Misery loves company.

[Mike O'Brien]

LOL. I doubt there is anyone with the answers. Cyano has been around forever for a reason. I think Randy recently stated that his Cyano problem was almost completely gone. And many people find that it disappears for no apparent reason as fast as it came. A very frustrating problem for many.

[fullmonti]

Thanks guys

I have been talking with austin93, he said he has same gray brown matt looking stuff I have. He sent a sample to Cliff & it was a kind of cyano, so I may not have any algae now. I want to save my corals that have the STN if possable, so I think I'll feed them a bit more for now & just live with the cyano, if needed get another 100 snails.

Going to get a different test kit to double check if PO4 & NO3 really are zero. Not sure if I should do any thing different if it is, cross that bridge when I get to it.

[tmz]

A few thoughts.

No. I don't think anyone has a clear one size fits all answer to control cyano. A clean tank with good parameters, light flow and low N. P and organic carbon will probably limit it. It is the true primordial slime and exists anywhere there is light and mositure. It will use PO4 and nitogen and seems to thrive on organic carbon too. As I understand it autotrophic photosynthetic cyano can create anoxic zones for anaerobic activity within it's mass which it can fix notogen when it's in short supply.So while it can create it's own fixed nitrogen it seems to take more energy to do so.

As for fish pee. Marine fish do pass limited amounts of urine but it's concentrated. Fresh water fish do the opposite,drinking little and passing lot's of urine. Wether it's urine or respired water excess nitrogen is still expelled into the water.

Detritus as it breaks down certainly contributes, N. P and C.

Often the dangers or organic carbon buildup are overlooked since most of us can't test for it. Nonetheless, it's there from foods, excrement,algae exudate, coral slime ,etc. and more of it when dosing organic carbon sources such as vodka and vinegar.. I suspect excess organic carbon has a good deal to do with stn, since it effects bacterial growth which may imbalance the coral's symbiont bacteria. So dosing organic carbon is not without risk and attention to exporting it via granulated activated carbon and heavy skimming,etc., are very important in my opinion.

It's also worth noting that PO4 inhibits the precipitation of calcium carbonate.Rapidly reducing PO4 via gfo or organic carbon dosing may enhance coral skeletal growth without enhancing tissue growth leading to burnt tips and triggering stn. For example you may run a tank with high PO4(.2ppm) and high alkalinity(13.5 dkh)and do quite well. Drop the PO4 to .05ppm or so and leave the alkalinty high and you may get burnt tips as was my experience.

I have been dosing vodka and vinegar for about a year in moderate amounts. I was dosing about 95% of the organic carbon from ethanol(vodka) and 5% from vinegar. I had some patchy cyano. After adjusting to 75% vodka and 25 % vinegar for the last couple of weeks, based on Randy's idea ,the cyano is gone. It seems bacteria that prefer the acetic acid(vinegar)compete somewhat better with the cyano in my system at least for now perhaps pending a different cyano strain.

[fullmonti]

Tom thanks for more good info

Been meaning to ask, when dosing vodka & vinegar is it any vodka & vinegar or some particular brand? I have been using zeo carbon (down to just 4 drops a day, more seems to make brown slime) & Cliff once suggested I might try alternating carbon sources. & would you dose the same amount as I have been?

It sounds like I should know, but who is Randy?

[tmz]

I use bottom shelf Barons vodka, no flavoring ,charcol filtered, 89 proof which is 40%ethanol and the rest distilled water. Vinegar used is plain white vinegar from the supermarket.

[tmz]

I don't know how much you are dosing nor what exactly you are dosing, I don't use zeo either so my dosing probably won't translate well to your situation. FWIW,however, I dose 24 ml of vodka and 60ml of vinegar per day for 550gallons.. Vodka contains 8x as much carbon by volume per Randy as vinegar does; so the 60 ml of vinegar is equal to about 8 ml of vodka. I also run gfo, gac, purigen ,two large skimmers, macro algae refugia ,deep sand bed and a small cryptic refugium.

[fullmonti]

OK thanks, I'll have to do some research on the comparison dosing.

If you had a link would love to see pix of your system?