ammonia in river

1. The ammonium ion concentration increases because the pigs' urine is seeping into the ground water and eventually into the river.

The ammonium in urine is used primary to excrete the excess acid in the body.

2. Fungi and algae can have a symbiotic relationship and form Lichen. Fungi can absorb minerals from rock and nitrogen from the air and also attach themselves firmly to rocks. Algae can then anchor themselves to the fungi and take in the minerals from the fungi. In return, the fungi can benefit from the photosynthesis ability of the algae.

3. Urine has uric acid, ammonium, urea, water
Feces is semisolid, with a mucus coating. Its brown coloration comes from a combination of bile and bilirubin, which comes from dead red blood cells. Main components are digested waste.
Dead Bodies has lots of bacteria and lavae that serve the decay them.

第一題 jklo君答得不錯啦.
第二題唔似講緊 lichen. 係唔係仲講緊河水呀? 河水中既algae唔不以直接使用ammonia, 要由fungi將ammonia 分解成 mineral, algae 先用得到. 而 anchorage 亦係. algae 本身冇根, 而fungi可以hold 住河床既石頭, 亦可以為algae作為 anchor.
第三題係咪想講, 佢地都有氮 =nitrogen? 氮係植物最需要既mineral, 因為製造蛋白質係需要大量既氮. 而urine,faeces和dead bodies 都有大量既氮既成份. 氮存在既形式可以係尿素urea, 可以係氮化物nitrate/nitrite, 亦可以係氨ammonia.