Originally Posted by
IbanEz
http:///forum/post/3240002
I recall from my time in planted freshwater tanks, that they do use ammonia before it is converted in addition to nitrate for growth. Here are two quick results for my search, I will search more further when I have the time.
Nitrogen is an element needed by all living plants and animals to build protein. In aquatic ecosystems, nitrogen is present in many forms.
Nitrogen is a much more abundant nutrient than phosphorus in nature. It is most commonly found in its molecular form (N2), which makes up 79 percent of the air we breathe. This form, however is useless for most aquatic plant growth.
Blue-green algae, the primary algae of algal blooms, are able to use N2 and convert it into forms of nitrogen that plants can take up through their roots and use for growth:
ammonia (NH3) and nitrate (NO-3).
As aquatic plants and animals die, bacteria break down large protein molecules into ammonia. Ammonia is then oxidized (combined with oxygen) by specialized bacteria to form nitrites (NO-2) and nitrates (NO-3). These bacteria get energy for metabolism from oxidation.
Excretions of aquatic organisms are very rich in ammonia, although the amount of nitrogen they add to waters is usually small.
There even exist bacteria that can transform nitrates (NO-3) into free molecular nitrogen (N2). The nitrogen cycle begins again if this molecular nitrogen is converted by blue-green algae into ammonia and nitrates.
Because nitrogen, in the form of ammonia and nitrates, acts as a plan nutrient, it also causes eutrophication. Eutrophication promotes more plant growth and decay, which in turn increases biochemical oxygen demand. However, unlike phosphorus, nitrogen rarely limits plant growth, so plants are not as sensitive to increases in ammonia and nitrate levels.
Also...
Plants prefer low levels of NH4 and they all definitely use NH4.
While high levels of NH4 can burn and harm plants, such levels are never reached in our tanks, our fish would die long before that.
NO3 is "preferred" in the ranges that are common in our aquariums.
At about 0.5 ppm NH4 or higher to about 2-4 ppm NH4, plants will take up more NH4 than NH3 for a given rate, at about 1ppm of NH4.
But our tanks typically have less than 0.1ppm of NH4 and plants take this up directly or the bacteria get it in fish only tanks, and a little bit in planted tanks. At this ppm range, the rate of uptake for NH4 is very slow, but very high for NO3 when the NO3 is 10ppm etc.
Plants will take up a much larger fraction of their N from NO3 and folks dose this in KNO3 form typically for plants if the NO3's run low.
So plants use both forms of N: NH4 and N03.
Although they are referring to fresh water plants, I am sure the same should apply for salt water plants.
The only vegetation I know of in the marine environment that MAY assimilate ammonium nitrogen is nitzschia closterium which is a phytoplankton. in any event why would the hobbyist want to remove the ammonia before they has a good colonization of bio filtration established
