2.3 Biogeochemical Cycles of the Green World (Planet Earth)
41
What is the role of the primary producer in a carbon cycle? Does the carbon
cycle begin with photosynthesis in plants? Briefly explain your answer.
Are plants the primary consumers of carbon dioxide? Explain. Does carbon
dioxide dissolve readily in water? Is all the carbon available always recycles
within the carbon cycle? In what way does carbon get into the soil?
2.3.2.1 Concepts of the Carbon Cycle
1. Carbon presence ascertains whether something is organic or inorganic.
2. Carbon moves through the ecosystem in various ways, including respiration,
photosynthesis, weathering, and geological processes.
3. Numerous factors, including anthropogenic activities and seasons, affect carbon
concentration in the atmosphere.
2.3.3 Nitrogen Cycle
The nitrogen cycle has three major steps: nitrogen fixation, nitrification, and
denitrification. It is defined as a biogeochemical cycle through which nitrogen is
converted into multiple chemical forms as it circulates via terrestrial, marine, and
atmospheric ecosystems (see Fig. 2.7). Nitrogen conversion can take place through
physical and biological processes. Some of the significant nitrogen cycle processes
are fixation, nitrification, denitrification, and ammonification (Gruber and Galloway
2008). A large proportion (78%) of the Earth’s atmosphere is made up of nitrogen.
Despite this, there is little atmospheric nitrogen available for biological use, thus
resulting in a scarcity of usable nitrogen. The nitrogen cycle is crucial to ecologists
since nitrogen availability can influence ecosystem processes such as decomposition
and primary production. Nitrogen exists in the environment in various chemical
forms, including ammonium nitrate, organic nitrogen, nitrous oxide, and nitric oxide
(Gruber and Galloway 2008). Many of the processes within the nitrogen cycle are
carried out by microbes.
Conceptually, nitrogen fixation refers to the conversion of nitrogen gas into
nitrites and nitrates through biological, industrial, or atmospheric processes. Nitrogen assimilation refers to the absorption of ammonium or nitrate from the soil
through plant roots. On the other hand, ammonification is beneficial for providing
living organisms with nitrogen (Gruber and Galloway 2008). Ammonification
occurs because of decomposers that convert plant and animal cells into simpler components, hence availing nutrients within the ecosystem. Nitrification is defined as the
conversion of ammonium nitrate by nitrifying bacteria. Furthermore, denitrification
refers to the conversion of nitrates into nitrogen gas. The process is facilitated by
41
What is the role of the primary producer in a carbon cycle? Does the carbon
cycle begin with photosynthesis in plants? Briefly explain your answer.
Are plants the primary consumers of carbon dioxide? Explain. Does carbon
dioxide dissolve readily in water? Is all the carbon available always recycles
within the carbon cycle? In what way does carbon get into the soil?
2.3.2.1 Concepts of the Carbon Cycle
1. Carbon presence ascertains whether something is organic or inorganic.
2. Carbon moves through the ecosystem in various ways, including respiration,
photosynthesis, weathering, and geological processes.
3. Numerous factors, including anthropogenic activities and seasons, affect carbon
concentration in the atmosphere.
2.3.3 Nitrogen Cycle
The nitrogen cycle has three major steps: nitrogen fixation, nitrification, and
denitrification. It is defined as a biogeochemical cycle through which nitrogen is
converted into multiple chemical forms as it circulates via terrestrial, marine, and
atmospheric ecosystems (see Fig. 2.7). Nitrogen conversion can take place through
physical and biological processes. Some of the significant nitrogen cycle processes
are fixation, nitrification, denitrification, and ammonification (Gruber and Galloway
2008). A large proportion (78%) of the Earth’s atmosphere is made up of nitrogen.
Despite this, there is little atmospheric nitrogen available for biological use, thus
resulting in a scarcity of usable nitrogen. The nitrogen cycle is crucial to ecologists
since nitrogen availability can influence ecosystem processes such as decomposition
and primary production. Nitrogen exists in the environment in various chemical
forms, including ammonium nitrate, organic nitrogen, nitrous oxide, and nitric oxide
(Gruber and Galloway 2008). Many of the processes within the nitrogen cycle are
carried out by microbes.
Conceptually, nitrogen fixation refers to the conversion of nitrogen gas into
nitrites and nitrates through biological, industrial, or atmospheric processes. Nitrogen assimilation refers to the absorption of ammonium or nitrate from the soil
through plant roots. On the other hand, ammonification is beneficial for providing
living organisms with nitrogen (Gruber and Galloway 2008). Ammonification
occurs because of decomposers that convert plant and animal cells into simpler components, hence availing nutrients within the ecosystem. Nitrification is defined as the
conversion of ammonium nitrate by nitrifying bacteria. Furthermore, denitrification
refers to the conversion of nitrates into nitrogen gas. The process is facilitated by