Nutrients are central to the function and growth of organisms. In an ecosystem decomposer organisms are essential in breaking down biomass matter and cycling nutrients. Animal waste and dead organic matter are broken down by bacteria and fungi into their constituent elements. Some nutrients are released into the soil and become available for uptake by the roots of the plants for production of new plant matter. Elements such as oxygen, hydrogen and carbon are transmitted by air and water to the living components of ecosystems. Decomposition of dead and waste organic material returns hydrogen and carbon to the atmosphere. Carbon is released as carbon dioxide from the decay of carbohydrates. Hydrogen and nitrogen are released from the decaying protein as ammonia.
Weathering also assists in releasing nutrients into the soil. However nutrients are also lost in the soil. litter stays in an ecosystem through run-off. Acid rain is an example of nutrient pollution in ecosystems.
We will now observe a particular ecosystem to further illustrate the importance of nutrient cycling in ecosystems. In the Amazon basin nutrient inputs occur through precipitation, wind borne dust, ash, through nitrogen fixation by organisms, weathering of sediments and aerosols.
Essentially producer organisms are responsible for the intake of mineral nutrients into the ecosystem. Thus they construct the very substance of life. Consumer organisms break down organic tissue and return the material in an form to be used again by plants.
Geographers have recorded the flows of nutrients from place to place and reached the conclusion that nitrogen fixation is of the utmost importance. Plants gain their nitrogen as nitrates. Bacteria produce nitrates from soil, air and ammonia, a product of the decay of proteins in dead tissue and waste.
As per information above, the success of ecosystems depends on how well they can produce, use and primarily recycle nutrients. Without nitrogen cycling organisms will not grow, therefore they would lose the ability to function and their roles would not be carried out resulting in the collapse of whole ecosystems.
Since the nineteenth century, humanity has become a global force altering more than half of the surface of the planet through urban-industrial growth, farming and forestry. The composition of the atmosphere has been altered, waterways enriched with nutrients. This choked the rivers with pollution. As well, soils have been degraded and eroded, and natural ecosystems broken up and their biodiversity diminished.
Human actions have impacted nutrient cycle in numerous ways. Fertilizers, pesticides and other agricultural chemicals are washed into the rivers and oceans. It is augmented by increased run off resulting in a loss of nutrients from the soil and litter level of ecosystems. In turn, this removes nutrients plants and animal's need to consume for food and to aid their growth.
In addition, sewage and effluents from aquaculture enterprises and other human developments introduce excess materials and nutrients into the marine environment, creating instability and stressing out specific components of an ecosystem. Combined further with problems of over-fishing, and other disturbances, the changes humans are bringing to the nutrient cycle in eco-sytem can be extensive
Energy flows in ecosystems are also cause for concern due to increased human impacts. Energy flow can be described as energy being used up by the organism (to move its muscles, digest food, excrete wastes, think, etc.) and/or lost as heat as it moves through ecosystems, and new energy is continually added to the earth in the form of solar radiation. An important fact is that energy does not recycle.
Human impacts on energy flows in various ecosystems are caused by land use, water and electricity/appliance household use, combustion of fossil fuels and nutrient flows. The HANPP Approach found that humans already appropriate one-quarter of global terrestrial NPP(net primary production), thus reshaping most of the earth's land - with potentially dramatic effects on biodiversity energy flows and the stability and resilience of ecosystems.
With so many ways in which humans can impact the energy flow and nutrient cycle of ecosystems, we must combat our disastrous effects by beginning to undo the damage we have caused. Starting with using less energy, preserving our natural resources (water) and using/taking only what we need, not what is luxurious and comfortable. If we pull together, educating each other on environmentally friendly habits then I believe we can reduce our footprint on ecosystems and admire there beauty once again.
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