I have two questions actually, one concerning Oxygen levels in the atmosphere while the other one concerning Carbon Dioxide levels.

 

a) How does burning of rainforests, or burning in general, affect oxygen levels in the atmosphere?

 

b) How would the addition of phosphorous and nitrogen fertilizer to the ocean help reduce its carbon dioxide levels? And what problems would adding the fertilizer cause?

1) Plants are the main producers of Oxygen as a byproduct through photosynthesis, rainforests have lots of plants, thus less rainforest = less oxygen

 

2) no clue, I've heard though that lots of carcinogens are from fertilizers

Hi. My sister did this in her science class, and I remember I helped with the asignment, but I can't remember much right now. I'll tell you this though. Phosphorus and fertelizers multiply Planktons, which in turn multiply fishes as secondary consumers. Planktons use up CO2 during photosynthesis. CO2 is usually added to lower Ph of water, as too much CO2 is detrimental to fishes. About the problems, I can only guess that high levels of the fertilizers will result in oxides, leaving the water stale and lacking oxygen.