A Challenging Question on Bacteria . . .

[aqua_chem]

Not necessarily. I really would like to see a comprehensive list of aquatic plants which are capable of absorbing and using ammonia ~ such a list might go a long ways toward answering some of these questions.

Most plants actually preferentially uptake reduced nitrogen (ammonia/ammonium) rather than nitrite or nitrate, and nitrite before nitrate. The theory behind this is that plants can more easily incorporate reduced ammonia into proteins, where with nitrite and moreson nitrate, the nitrogen must first be oxidized, representing another energy investment.

I actually just found an article in Aquatic Botany (a peer reviewed journal) that found that duckweed would absorb 100% ammonia when both ammonia and nitrate were present. I would think that this would translate to other plants as well.

 

[Wy Renegade]

Most plants actually preferentially uptake reduced nitrogen (ammonia/ammonium) rather than nitrite or nitrate, and nitrite before nitrate. The theory behind this is that plants can more easily incorporate reduced ammonia into proteins, where with nitrite and moreson nitrate, the nitrogen must first be oxidized, representing another energy investment.

I actually just found an article in Aquatic Botany (a peer reviewed journal) that found that duckweed would absorb 100% ammonia when both ammonia and nitrate were present. I would think that this would translate to other plants as well.

Yet doesn't this fly in the face of conventional wisdom? With the exception of Legumes, every nitrogen cycle diagram out there shows assimilation of nitrogen by plants only in the form of nitrate after it has been converted into from ammonia into nitrite and then finally in nitrates.

 

[OasisKeeper]

Yet doesn't this fly in the face of conventional wisdom? With the exception of Legumes, every nitrogen cycle diagram out there shows assimilation of nitrogen by plants only in the form of nitrate after it has been converted into from ammonia into nitrite and then finally in nitrates.

Now you've done it. You've made me pull out Walstad.

The short answer is, I believe, aquatic plants are efficient in consuming ammonia directly. I'll see if I can find a citation if you need it.

So, anybody got a decent table with comparative areas of differing filter media?

 

[aqua_chem]

Yet doesn't this fly in the face of conventional wisdom? With the exception of Legumes, every nitrogen cycle diagram out there shows assimilation of nitrogen by plants only in the form of nitrate after it has been converted into from ammonia into nitrite and then finally in nitrates.

Terrestrial plants work on a different premise than aquatic plants. For one, the medium, soil or dirt or whatnot, is different than in aquatic plants. Many aquatic plants do not absorb nutrients through their roots as much as terrestrial ones do. Why does this matter? Soil is absolutely teeming with well established microbial life, including nitrifying bacteria. Any ammonium will be quickly converted to nitrate, limiting its availability all together.

This effect will be especially noticeable with stem-type plants, like the wisteria that was present in the tank in questions. Stems bypass substrate entirely, absorbing nutrients through their stems and leaves. Ammonia/ium and be efficiently delivered directly, bypassing the microbial gauntlet.

 

[mfdrookie516]

I guess I should note in response to what was said about my tank, that my plants are looking fantastically crappy. There is very little growth. I do weekly-ish 50-60% PWC's, and even in my non planted tanks, my nitrate was always that low. I guess i should have given some more info, though I was kind of in a hurry.

I don't attribute the plants to much help at all really. I've stopped dosing ferts and injecting co2 because I really just don't have the time or patience to mess with them any longer. They are what they are. If they die, oh well. I won't subject the fish to the same treatment though. I make sure they've got what they need. Part of the reasoning behind my 'experiment' was to try and 'force' the bacteria to establish itself anywhere except the filter. This is an effort to both attempt more self sustaining aquarium, and to rid any chance of a filter change causing a mini cycle. The logic is there in my head if it didn't make sense in print.

 

[auxillaryspade]

If that is true (which honestly I have my concerns with), it should be indisputable evidence that there are significant differences between FW and SW nitrifying bacteria...or at the very least their behavior in home aquaria compared to other environments. Obviously in FW, filling a tank with water from an established tank and stocking it is a recipe for disaster. Now there are situations where taking a piece of filter media and squeezing it out into water to donate into a new tank can help introduce beneficial bacteria into a tank, however it is in no way an "insta-cycle" as people refer to certain ways to transplant bacteria.

I've used this following example several times before on the site...but it is true based on my experience, both first hand as well as all the members I communicate with daily on the site-

Substrate, decorations, filter squeezings, etc...are a true way to "seed" a tank. It introduces some degree of beneficial bacteria into a tank and lets it begin colonizing...basically planting a seed in order for it to grow.

Now, donating filter media is like planting a fully grown tree instead of it's seedlings. It instantly brings over a significant amount of beneficial bacteria which should immediately be capable of handling a larger amount of toxins compared to any other type of item. Again, this is not speculation, this is experience.

As previously stated, a tank being considered "cycled" simply refers to the proportion of beneficial bacteria : toxins produced in a tank. I really do believe that simple experience trumps the need to study at length (although I've probably read every article on Google about nitrifying bacteria) in terms of the amount of beneficial bacteria found in filter media vs substrate or other items.

When I was going to school for marine biology my roomate decided he was going to get a 150 gallon tank( he knew nothing about fish) and decided he wasw going to do this by himself. he then proceeded to scoop gravel out of the backyard in Iowa put it in the bottom of his tank. he then installed two of the cheapest aquarium heaters I have ever seen( I think he bought them from a garage sale from the 80s. he then went to Walmart and bought a 10 dollar aerator that came with air stones. he then took water out of the tap (well water) filled his aquarium and bought 9 red bellied piranhas. this tank has had nothing added to it besides the occasional water that evaporates for over 6 years. all of his fish are healthy and after my protesting for about a month he finally let me test his water. he maintains a perfectly healthy tank. the whole set up well under 100 dollars( including the fish). I don't know if he still does but he used to feed his fish left overs... so saying that there is a significant difference between salt water and freshwater here is an example worth looking at.

 

[auxillaryspade]

I quoted the wrong reply.