(par 3. 3.2) Nitrogen Cycle
http://eschooltoday.com/ecosystems/the-nitrogen-cycle.html Nitrogen is also key in the existence of ecosystems and food chains. Nitrogen forms about 78% of the air on earth. But plants do not use nitrogen directly from…
(par 3. 3.2) Carbon dioxide accumulates as seas and forests struggle to absorb
http://www.independent.co.uk/environment/carbon-dioxide-accumulates-as-seas-and-forests-struggle-to-absorb-it-9722224.html Carbon dioxide is being accumulated in the atmosphere at the fastest rate since records began, as scientists warn that the oceans and forests may have absorbed so much CO2…
(par 3. 3.2) Greenhouse Gases Hit Record High Amid Fears of CO2 Saturation Point
Greenhouse Gases Hit Record High Amid Fears of CO2 Saturation Point http://news.nationalgeographic.com/news/2014/09/140909-record-greenhouse-gases-carbon-sinks-global-warming-ocean/ Data suggest natural “carbon sinks” may be nearing exhaustion, say some scientists, although others disagree. The burning of…