(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 the air. This is because nitrogen itself is unreactive, and cannot be used by green plants to make protein. Nitrogen gas therefore needs to be […]
(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 that their crucial function as “carbon sinks” is now severely threatened. The jump in atmospheric CO2 is partly the result of rising carbon emissions as […]
(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 coal worldwide, as shown here in Jharkhand, India, contributes to the amount of greenhouse gases in the atmosphere. Photograph by Robb Kendrick, National Geopgraphic Creative […]