When oxygen levels in water get low... When algae takes over a lake. The oxygen levels will get low.
water!!!!
Change the water. This usually happens if the water is low in oxygen levels. There are other problems that may result in this as well.
it rises
It becomes into humus
Problems With Electrolyte Balance (causes and symptoms of low levels): http://www.merck.com/pubs/mmanual_ha/sec3/ch18/ch18d.html
In the ocean on top of the water or in low depth levels.
They affect the river by changing the temperature of the water, if the pH levels are high then the water is warmer and if the pH levels are low then the water is cold.
Your mum has sex with me.
eutrophication
Amphetamine has a very low solubility in water.
water, i would guess.