why do swamps and bogs have low nitrogen levelS?

Question

GENERAL GR 10 QUES

Answer 1

It's due to the nitrification / de-nitrification cycle.

Nitrogenous material (including ammonia but also 'organo' nitrogen) is converted by aerobes: bugs that use oxygen for respiration. The N and O get together and make NO2 (or NO3?), but still in complexes with the solution (meaning it does not go into the gas phase). This is the nitrification step.
The next step (de-nit) is the conversion of the nitrates (now I'm thinking it is NO3, but this would work for NO2 as well). Anoxic bugs (very different from the aerobes above) use the nitrogen oxides as their oxygen source. Note that these are NOT anaerobes. These last do not want any form of O2.
The result of the de-nit step is gaseous N2. It does not like to stay desolved and simply de-gasses (goes into the air).
There are also some bugs that go both ways (facultative), but that's beyond your question.

Swamps and bogs have been around for quite some time. All of their nitrogen has been converted and simply gone into the atmosphere.

A side note: the reason de-nit step happens so prevelently in swamps/bogs is that very little oxygen is dissolved into the soup (water?). There is no agitation of these systems to get oxygen dissolution into the swamps. The very little that does get dissolved at the surface is quickly consumed. Therefore, the anoxic bugs grow freely and chew up all the nitrogen oxides making N2 gas. When the nitrogen is gone, anaerobes take over. They are the ones who like to produce lovely (malodorous) compounds like H2S and mercaptans to name a few. That's why these places have their smell (rotten eggs).

Answer 2

I'm not sure about swamps, but in bogs there is very little decomposition occuring because of low acidity. The low acidity is caused by sphagnum moss that is common in bogs. They produce the acid. If things don't rot, the nutrients do not get recycled. Bacteria will use up all the available nutrients and there will be little left. -- interesting note-- you find lots of carnivorous plants in bogs because these plants are able to get nitrogen from digesting insects! They are adapted to low nitrogen conditions.

I guess swamps will have low decomposition rate, but this will be due to anoxic conditions (low oxygen). When ever you have standing water, you get low oxygen conditions.

Denitrifying bacteria, the bacteria that converts nitrates into nitrogen gas are anaerobes, so it would also make sense that in an anaerobic conditions, you will have a lot of denitrification going on removing nitrogen from the soil.

Answer 3

Swamps And Bogs

Answer 4

The reason swamps and bogs have low nitrogen levels is that they have much vegetation such as trees, shrubs and all sorts of other plants. Plants use carbon and give off oxygen so if you have a lot of plants your going to have to have lots of carbon and there is going to be a lot of oxygen.