My teacher was talking about how if we added nitrogen and phosphorus fertilizers in the ocean, we would help reduce carbon dioxide. I don't understand. How does that work?

Answer 1

Here are some articles which discuss that.

http://scholar.google.com/scholar?q=the+effect+of+nitrogen+and+phosphorus+fertilizers+on+the+ocean&hl=en&um=1&ie=UTF-8&oi=scholart

Answer 2

nitrogen and phosphrous are fertilizers, and that promotes growth of sea plant life (algae), which uses carbon dioxide to manufacture more plant tissue.

However, you teacher is probably wrong in the longer run. The algae will eventually die, and the carbon in it has to go somewhere. It is not clear what the long term consequences are.
There is a better way of getting algae to grow, that is seeding with iron, as that is the limiting factor in algae growth in the ocean. Several experiments have been done, but the long term consequences are still out.
http://hubpages.com/hub/What-is-the-role-of-accumulating-ocean-algae-in-global-warming_1

Answer 3

Thanks alot everyone! That really helped.