Biomass growth terrestrial

The most widespread and practical process for capture of this energy as organic fuels is the growth of virgin biomass. As already discussed, extremely large quantities of carbon are fixed each year in the form of terrestrial and... 

The average net annual productivities of dry organic matter on good growth sites for terrestrial and aquatic biomass are shown in Table 4.12. With the exception of phytoplankton, which generally has lower net productivities. 

Responses of terrestrial ecosystems to increased atmospheric carbon dioxide concentration are of great current interest. Part of this debate relates to the role of limitation by various nutrients, like nitrogen, phosphorus and other vital nutrients on growth and biomass accumulation in terrestrial vegetation. Because vegetation must maintain a nutritional balance, it is expected that nutrient limitation will constrain responses to increased CO2 level. 

On a global basis, macroscopic, multicellular algae (seaweeds) make only a minor contribution to marine primary production 95% is accounted for by the phytoplankton. Phytoplankton are short-lived compared with terrestrial plants, especially trees, and do not need to produce supportive structural tissue, which is mostly photosynthetically inactive.Virtually the whole of the net primary production of phytoplankton is directed towards reproduction and growth, but much of this is grazed by herbivorous zooplankton. As a consequence of this efficient grazing, phytoplanktonic biomass is low and the ratio of animal to plant biomass in the oceans is greater than on land. 

Carbon is stored in terrestrial ecosystems in two main forms carbon in biomass ( ), principally as wood in forests and carbon in soil H). The lifetime of carbon in these reservoirs can be quite different. If elevated C02 leads to increased growth of a tree, this results in a C02 sink. The tree might typically live for a century before it dies and decomposes, releasing C02 back into the atmosphere via heterotrophic respiration. Large terrestrial carbon reservoirs in the form of trees or forest floor litter are susceptible to rapid return to the atmosphere through fire. 

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