CYCLES OF NATURE

Ecosystems, like other systems, follow the physical principles of conservation of matter and energy. Materials move among, through and between living things and the physical environment, often being transformed in the process. IMAGINE being given the job of doing BOOK KEEPING on the flow of each atom, ion, and molecule as they move between the living and nonliving things in an ecosystem. There are three major types of nutrient cycles:

1) hydrologic--water cycle; ice, liquid water, water vapor; the availability of water is the biggest factor in determining what kinds of organisms can live in a given location
2) atmospheric--gases in the atmosphere; nitrogen gas, carbon dioxide gas
3) sedimentary--earth's crust is the main storehouse; most elements move from land to sediments to seaand then back to the land; phosphorus

Example of Water Cycle:
Water cycle is powered by energy from the sun and by gravity. Incoming solar energy evaporates water from oceans, lakes, streams. Winds and air masses move water vapor over parts of the earth's surface. Falling temperatures cause the water to condense into tiny droplets that form clouds or fog. Water vapor collects on air particles and condenses at the dew point. Precipitations falls back into the oceans, lakes etc and the rest over land. The precipitation replenishes the oceans and lakes, BUT surface water may cause soil erosion. Soil erosion moves soil and rock fragments from one place to another. Some of the surface water moves through the soil dissolving minerals from rocks. Some of this water is stored as groundwater. Evaporation and precipitation are processes that purify water by removing the impurities dissolved in water. In this way, the water cycle can be seen as a natural renewing agent of water quailty.

Example of Carbon Cycle:
Carbon is essential for life! You can find it in all organic molecules--fats, carbohydrates, proteins, nucleic acids (DNA). The carbon cycle is based on carbon dioxide gas. Producers remove carbon dioxide gas from the air and or water. They use this as the framework for building complex organic molecules in a process called photosynthesis. Producers and Consumers and Decomposers breakdown these organic molecules for energy and in the process release carbon dioxide. This process is called cellular respiration. The producers, consumers, and decomposers release this carbon dioxide back into the atmosphere or water for reuse by producers.

Example of Phosphorus Cycle:
Phosphorus is an essential nutrient for all living things. It is a major part of the DNA. Phosphorus cycles through water, the earth's crust, and living organisms. Phosphorus moves from phosphate deposits on land and shallow ocean sediments to lving organisms, and then back to the land and ocean.