question

[Bill Nye Guy]

I was just woundering what is the effects of nitrogen and phosphorous fertilizers running into a body of water, I heard it negatively effects life.

 

Could someone explain why to me. I read a topic about this but was not explained the reasons why. thanks alot everyone.

[ecoli]

NItrogen and phosphorus are necesary part of algae and photoplankton growth. Nitrogen-limited off-shore regions and Phospohrus-limited lakes depend upon the availability of these nutrients.

 

However, if you get to much of these nutrients, from runoff of fertilizers and feces from farms, you get blooms of algae and plankton that literally take over the water. You get so much growth that the water eutrophicates.

 

What happens, is the oxygen cannot transfer into the water as well, because of the excess growth, and organisms die. Detritovores use oxygen to break down the organic matter. Water becomes hypoxic and looses a lot of dissolved oxygen. However, organisms need the oxygen to breathe, and will also die... it's a vicious cycle.

 

Also, dense mats of alge at the top will block sunlight from all but the top layer of the lake, so you get large amounts of growth in the top, but virtually none anywhere else.

 

Eutrophication is a very serious problem, and can be solved by smart fertilizer use and educating farmers about the harm they can do, just by where they put their manure piles.