The carbon and nitrogen cycles



The world has natural cycles that keep the balance in nature and in the atmosphere. However, human interference has to lead to these cycles changing. This is bad for all life on the planet because it is disrupting sensitive ecosystems and causing widespread climate change. Here are the two main cycles for all life and what they do;


The carbon cycle


Carbon is the key element to life and so, a stable carbon cycle means that all organisms live in harmony. However, this is the one most people know about and worry, rightly, about. Carbon dioxide makes up a very small amount of the atmosphere and it is essential to us because it is the main greenhouse gas that allows some radiation from the sun to stay in the atmosphere heating the world. For the last 100 years, humans and their factories have been pumping tonnes of carbon into the atmosphere which means more heat is being trapped therefore heating the earth and causing the global warming phenomenon.


How the carbon cycle works;


The cycle of carbon consists of carbon dioxide being transferred to organisms that transfer the carbon to the next and so on until it reaches the atmosphere as carbon dioxide again.
Carbon dioxide gets removed from the atmosphere by plants using photosynthesis. The carbon becomes some of the more complex molecules in the plant such as proteins.
Next, when an animal eats a plant the carbon contained in the plant gets transferred into the new organism. Then when the animal excretes waste microorganisms feed on the nutrients in it which contains the carbon.
The carbon in the animals and microorganisms is usually released back into the atmosphere through respiration but it is now also released by fossil fuels which are increasing the amount of carbon in the atmosphere. However, some carbon gets trapped by certain substances such as water and calcium. The ocean contains about 90% of all carbon in the world through algae and other sea species. Shellfish have shells made from a molecule called calcium carbonate, this is one of the main trappers of carbon because it reacts with calcium easily. Also, decomposition or decay in organisms releases carbon back into the atmosphere.


Next is the nitrogen cycle;


Nitrogen compounds are found in the proteins of cells. Nitrogen from the air is converted to nitrates which can be absorbed and passed on from organism to organism. It is returned to the atmosphere in nitrogen form and this completes the cycle of nitrogen. Nitrogen is one of the most need nutrients for plants to grow healthy this is why farmers and gardeners use fertilisers to grow their plants, this is because the fertilisers have nitrogen along with other nutrients in them to make the plants grow. However, this is a really bad thing for humans and the environment. The nitrogen in fertilisers can leak into streams and rivers which cause algae to grow rapidly as a result of the new found food source(nitrogen), this growth in algae means that all the oxygen and light are not reaching the deeper parts of the water. This means that fish suffocate and underwater plants can't photosynthesis, therefore killing off ecosystems. If no algae are present the nitrogen effects us more! This is because the nitrogen reacts with the water and creates a molecule that we call acid rain. This dissolves stone and metal which weakens bridges and buildings which make them more likely to collapse, this would cause a massive problem for humanity if all the bridges collapsed. It also gets worse because burning fossil fuels releases more nitrogen into the atmosphere which reacts with the ozone layer, destroying it and causing harmful UV radiation to hit earth causing cancers and burns.


How the nitrogen cycle works;


About 78% of the air we breath is nitrogen, it is very unreactive in the state and can't be used for much. So it must be converted into nitrates for optimal performance. Nitrogen-fixing bacteria in the roots of plants is able to convert it. Also lightning converts nitrogen into nitrates.
Plants absorb these nitrates to create proteins to grow.
Then animals eat the plants and the nitrogen proteins get passed along to the animal similar to that of the carbon cycle.
Then when the animal excretes waste, similar to the carbon cycle, the decomposer bacteria gain the nitrogen nutrients. Denitrifying bacteria in the soil breaks down nitrates and release them back into the atmosphere.