CO2 Global Map

Influenced by several news lately about the atmospheric carbon, I am writing a post about the CO₂ global map. NASA have given into publicity a video which illustrates the global carbon dioxide concentration. 

 NASA- A Year in the Life of Earth's CO2

The model simulation gives the daily carbon concentration of the year 2006. These data are very useful for the scientific community, giving an illustration of the human impact on global scale. In combination with the 2^nd post (Human influence in the Atmosphere!) , we can observe the high concentration of carbon dioxide across the north hemisphere, due to carbon emissions from North America, Europe and Asia. 

As the speaker describes, during the spring and summer in the north hemisphere, the photosynthesis influences positively the carbon sequestration in the soil (5^th post Carbon travel, destination: Soil), thus the carbon concentration in the air has lower levels comparing to winter concentration.

In addition, the speaker points out that the carbon dioxide travels around the globe, been affected by the weather, giving to the problem global dimensions. On the other hand, a dangerous gas for the environment and the human, the carbon monoxide is emitted in the south hemisphere.

This kind of modelling will help to understand how carbon emissions affect the environment.   The rise of this element in the atmosphere will cause problems to the humanity in the near future.

Soil organic matter – decomposition rates

In previous posts we discussed how the organic carbon is transferred to the ground and what exactly happens in the organic matter during the decomposition procedure.

 But how fast is it decomposed?

 Carbon Flow in Terrestrial Reservoirs (Credit: David Bice)

The organic matter influences the microbial activity in the soil, acting as a carbon source for the microbes (Agren and Bosatta, 1996).As the organic matter is transferred from the plants to the soil, the different substances are decomposed with different speed depending on their structures (Stockmann et al., 2011). For example, leafs are decomposed faster than the wood.

Biogeochemical cycles (2014 UCAR)

Many studies (Meentemeyer, 1978; Parton et al., 2007; Melillo et al., 1982) have concluded that the main factors contribute in the decomposition rate, are:

1. Climate
2.  Humidity
3. Microbiology of the soil 
4. Quality of the organic matter

The climate and the humidity of the soil affect the microorganisms, thus the decomposition of the organic matter. In general, the quality of the organic matter can be characterized by the C/N (Carbon/Nitrogen) ratio. To be more specific, the higher the C/N ratio, the lower the decomposition rate of the organic matter (Melillo et al., 1982; Gupta and Germida, 1988). That shows the importance of the relation between the nitrogen and the carbon cycle, giving the ‘title’ of the limiting factor for the microbial activity.

 Carbon and Nitrogen cycles (2014 UCAR)

 

The increase of the CO₂ emissions helps the greenhouse effect rising the global temperature (see 3^rd post-Human influence in the Atmosphere!). The decomposition of the soil carbon is affected by the temperature because there is a positive feedback to the microbial activity due to temperature increase. This means that the terrestrial carbon is released back to the atmosphere (Stockmann et al., 2011).

A general view of the carbon movements in the terrestrial ecosystem is illustrated below:

 Terrestrial Sequestration Diagram. (Source: EPA)

See you very soon!