Nitrite a problem? Maybe not!

[JohnO]

Here's something to chew over :-) It was a reply to a question about the Nitrogen cycle.

Note the reference to Nitrite and its effect on marine fish as against freshwater fish.


" The nitrogen cycle is essentially the same in freshwater and marine situations and I have described it here: The Nitrogen Cycle. About the only thing that varies in the cycle is the genera and species of bacteria that perform the mineralisation, nitrification and denitrification. In both freshwater and marine conditions, nitrite is produced and oxidised as part of the cycle.

The main difference between freshwater and marine conditions is the toxicity of the nitrite. Many fish in freshwater cannot tolerate even small concentrations of nitrite. The recommended level for salmonids is less 1.6 mg/L of nitrite. Other fish have a lower tolerance and some freshwater fish can tolerate over 100 mg/L of nitrite. This all changes in saltwater due to the high concentration of chloride which inhibits the uptake of nitrite across the gills. In fact, the recommended treatment for high nitrite in freshwater aquaria and aquaculture ponds is the addition of salt, which adds chloride.

The 24 hour LC50 for spotted sea trout in water with a salinity of 14 ppt is over 3,000 mg/L of nitrite. (LC50 refers to the lethal concentration which would result in the death of 50% of the individuals exposed to that concentration, so 24 hour LC50 means that if the fish were exposed to 3,000 mg/L of nitrite for 24 hours, 50% would die.) The "safe level" of nitrite is less than the 24 hour LC50, but even if 1% is assumed, the safe level would be around 30 mg/L.

The more commonly used indicator is the 96 hour LC50 which is generally around 10 times the safe level. The 96 hour LC50 for European sea bass is around 300 mg/L, so a safe level of 30 mg/L could be assumed. In other studies, fish have shown no acute toxicity to nitrite at as high as 5,000 mg/L. "

[Craig Manoukian]

My chemist friend eweldon explained to me that inverts are much more sensitive to nitrites than fish.

Very interesting stuff, who is the author?

[reiple]

good info. the salt on fw tanks were highly recommended for the health of coldwater fish like goldfish. helpful!

[JohnO]

My apologies, the quote was a paraphrase from:

Fish Disease: Diagnosis and Treatment by Edward J Noga


I think it is quite interesting. Do a quick search on the Nitrogen cycle on the Internet and I am sure you will find lots of information stating that even the smallest traces of Nitrite is extremely toxic to SW fish. :-)

I guess it just proves that you shouldn't always believe in entirety what you read. :-)

John

[rayjay]

I don't think I'll test the theory.
I DO know however, that high nitrites tend to kill of my brine shrimp that I raise.

[MacnReef]

High nitrites have more of an effect on inverts than it does fish but this is also determined by the pH. In freshwater a higher ammonia or nitrite with a pH of 7 is less toxic than a pH below 7.

But another problem that is failed to be pointed out. Nitrobacter is the bacteria that converts nitrites to nitrates and they do this very efficiently. So if you have high nitrites, guess whats going to happen when those get converted???? High nitrates are major problems in reef aquariums because of all of the light. This is a good way to have bad algae blooms.

Mike

[JohnO]

Mike,

Thanks :-) The post was about misconceptions and borrowing knowledge from one environment and applying it to another because they are thought to be similar ( eg freshwater to saltwater ).

Thanks anyway, as what you wrote is important but not quite what the topic was intended to be about.

It seems that you have some freshwater knowledge, can you think of other technologies, concepts etc that have been applied to saltwater incorrectly. Anyone else too for that matter :-)

JOhn

[MacnReef]

Yeah...we are getting along! [smiley=2thumbsup.gif] lol

Sorry I got a little off topic... [smiley=anxious.gif]

Yeah, saying that the foam on a beach from tides is basically a protein skimmer in action in the ocean...thats always been funny. If that were the case, considering the oceans mass, a staggering 141 billion billion metric tons. The skimming taking effect is very minimal, wouldnt you think...

Mike

[Birdlady]

It's not that the foam is what 'cleans' the ocean, it is just the same physical reactions...foam fractionation or protein particles adhering to tiny bubbles. That is why there is scummy foam. That is just how I understand it and how I started to understand the concept of skimming when I first started in the hobby. Laymen's terms, so to speak.

I think the ocean has enough LR and LS to filter itself pretty well LOL!

[Birdlady]

Plus, the 'skimming' action takes place only at the shorelines, not over the entire ocean so that is alot less area, yes?