Ecosystems and How They WorkThe recycling of elements is another vital functional process occurring in all ecosystems. Describe the biogeochemical cycles for carbon, phosphorous, and nitrogen. How have humans impacted these three cycles?
Ecosystems and How They Work
Carole Holmes
March 25, 2006
Unit 1: Individual Project (SCI210)
Laura Step
Ecosystems and How They Work
Revolutionary changes in human culture have greatly changed the relationship between humans and the environment. How have the Neolithic and Industrial Revolution impacted the natural environment, and what is meant by the Environmental Revolution?
The Neolithic Revolution has impacted the natural environment because it allowed a shift from hunting and gathering to agriculture which has lead to more permanent settlements and population increases. This was a major turning point in human history. The expansion of humans and activities into the natural environment increased uniformity in landscapes and greatly reduced the area of each wildlife habitat.
The Industrial Revolution impacted the natural environment because the mass consumption of fossil fuels and natural resources used to push this revolution forward has caused a great deal of environmental damage such as pollution and exploitation. The industries discharged foul, sometimes toxic, solid, liquid, and gaseous wastes as well as loud, repetitive, mechanical noises and vibrations into the surrounding air, water, and land. These emissions blackened the air and water and disturbed ecosystems wherever rivers were dammed for power.
The Environmental Revolution is "a coming change in the adaptation of humans to the rising deterioration of the environment". (Wright, 2005). I believe that this type of revolution would require sacrifices but would lead to enormous gains. It would have to start at grass-root level if we want to preserve the world's limited natural resources, its forests, and wild animals. The steps we take now may be crucial in determining the fate of humanity.
Ecosystems and How They Work
The recycling of elements is another vital functional process occurring in all ecosystems. Describe the biogeochemical cycles for carbon, phosphorous, and nitrogen. How have humans impacted these three cycles?
The biogeochemical cycle of carbon constitutes the basic mechanism for the production of renewable resources such as food, fiber, and fuel and for the removal of organic waste material through mineralization. Organisms use carbon from the ocean and atmosphere to produce organic matter and construct shells of calcium and carbonate.
Carbon dioxide is release from cellular respiration, which is used ...
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Ecosystems and How They Work
The recycling of elements is another vital functional process occurring in all ecosystems. Describe the biogeochemical cycles for carbon, phosphorous, and nitrogen. How have humans impacted these three cycles?
The biogeochemical cycle of carbon constitutes the basic mechanism for the production of renewable resources such as food, fiber, and fuel and for the removal of organic waste material through mineralization. Organisms use carbon from the ocean and atmosphere to produce organic matter and construct shells of calcium and carbonate.
Carbon dioxide is release from cellular respiration, which is used in photosynthesis. Photosynthesis then releases oxygen used in respiration. Animals depend on green organisms for organic food, energy, and oxygen. Organisms exchange carbon dioxide with the atmosphere in the carbon cycle. Carbon dioxide is taken up by plants on land through photosynthesis and is then incorporated into food. Some of this carbon is returned to the atmosphere in the molecules of carbon dioxide when organisms respire.
Phosphorus is an important element in phosphate compounds in plants that have help capture solar energy and convert it to chemical energy in its bonds. This energy is used to make complex carbon compounds. When rocks begin to weather, they make phosphate ions available to plants through uptake from the soil. There is a small amount of phosphorous in mineral apatite which is enough for all living things to utilize. Runoff returns phosphates to aquatic systems and sediment. Phospholipids, ATP, teeth, bones, and shells are places where organisms use phosphate. Because most the Phosphate is currently being used in organisms, it is a limiting nutrient.
When nitrogen is added to organic compounds and nitrogen gas is chemically
reduced. Nitrogen fixation occurs. Atmospheric nitrogen is converted to ammonium by some cyan bacteria in aquatic ecosystems and by nitrogen-fixing bacteria in the nodules on roots of
Ecosystems and How They Work
legume plants in terrestrial ecosystems. Plants take up both NH4+ and nitrate (NO3-) from soil. The nitrate (NO3-) is enzymatically reduced to ammonium (NH4+) and used in the production of both amino acids and nucleic acids. Cosmic radiation, meteor trails, and lightning in the atmosphere converts Nitrogen gas (N2) to nitrate (NO3-).Nitrogen gas (N2) is converted to nitrate (NO3-) by cosmic radiation, meteor trails, and lightning in the atmosphere. We can now manufacture nitrates for use in fertilizers because of human technology. In soil, bacteria convert ammonium (NH4+) to nitrate (NO3-) by a two-step process. Nitrite-producing bacteria convert ammonia to nitrite (NO2-). Next, nitrate-producing bacteria convert nitrite to nitrate.
Humans impact the carbon cycle during the combustion of any type of fossil fuel, which may include oil, coal, or natural gas. During combustion in the presence of air (oxygen), carbon dioxide and water molecules are released into the atmosphere. The question of what happens to this extra carbon dioxide that is released into the atmosphere remains unanswered. One human impact on the nitrogen cycle is nitrate pollution of groundwater, arising from poor animal and human waste management practices. Humans use mined phosphorus in fertilizers, animal feeds, and other products which are transported to agricultural areas all over the world. There they are incorporated into the soil, either directly as fertilizers or indirectly as excess phosphorus in manure resulting from the use of high-phosphate animal feeds. These poor land-use practices increase erosion of this phosphorus-laden soil. Human actions accelerate the natural cycle in the entry of phosphorus into the biosphere from rock and in the movement from soil into aquatic
ecosystems. By moving phosphorus away from certain spots on the Earth's surface and to others we radically alter the distribution of this element on the planet's surface.
Ecosystems and How They Work
The goods and services performed by natural ecosystems are essential to human survival. What is their overall value, and of what significance is it to measure this value?
Natural ecosystems and the plants and animals within them provide humans with services that would be very difficult to duplicate. While it is often impossible to place an accurate monetary amount on ecosystem services, we can calculate some of the financial values. Many of these services are performed seemingly for "free," yet are worth many trillions of dollars, for example: 80% of the world's population relies upon natural medicinal products. Of the top 150 prescription drugs used in the U.S., 118 originate from natural sources: 74% from plants, 18% from fungi, 5% from bacteria, and 3% from one vertebrate (snake species). Nine of the top 10 drugs originate from natural plant products.
The significance of measuring the value of natural ecosystems is that it helps us to realize that the choices we make today in how we use land and water resources will have enormous consequences on the future sustainability of earth's ecosystems and the services they provide.
Ecosystems and How They Work
References:
The biosphere and mass extinctions Retrieved March 24, 2006 from http://www.emc.maricopa.edu/faculty/farabee/BIOBK/BioBookcycles.html
Carbon cycle Retrieved March 23, 2006 from www.elmhurst.edu/~chm/vchembook/306carbon.html
The global phosphorus cycle Retrieved March 23, 2006 from http://civil.colorado.edu/~amadei/CVEN4838/PDF/EP152B.pdf#search='human%20impact %20on%20phosphorus%20cycle'
Human impact on the natural environment Retrieved March 23, 2006 from http://www.hobart.k12.in.us/jkousen/Biology/impact.html
Wright, Richard. (2005). Environmental Science. Ninth Edition. Pearson Education, Inc. Prentice Hall Upper Saddle River, NJ. 07452