How Reefs Form:
• Form in shallow waters
• Tropical waters
• Along islands and continents
• Corals, made of Calcium Carbonate die and bodies stay
• Corals living
Importance of Coral Reefs:
• Biodiversity
• Home for vertebrates, invertebrates, and plants
• Productivity
• Recycling of resources
• “Tropical Rainforests of Oceans”
Background to Life:
• Calcium Carbonate skeleton
• Covered in Zooxanthellae which give it color
• Cnidaria
• Capture planktonic organisms with nematocyst
Degradation:
• Overexploitation
• Overfishing
• Sedimentation
• Nutrient overloading
Bleaching:
• Stress response
• Densities of Zooxanthellae on coral declines
• Concentration of Photosynthetic pigments falls
• Clear color from calcium carbonate skeleton
• No pigments on top if photosynthetic gone
• Causes death of coral
Causes:
• Temperature
• Solar irradiance
• Sub aerial exposure
• Sedimentation
• Fresh Water Dilution
• Inorganic Nutrients
• Xenobiotics
• Epizootics
Thursday, March 15, 2012
Friday, March 9, 2012
AV: Desertification
Desertification is an environmental issue regarding the destruction of once useable land, where fertile ecosystems become arid and desert-like. This issue has lead to both drought and famine, taking a toll on many underdeveloped countries around the world.
The cause of desertification is the result of several discrepancies to the very fragile ecosystem at hand. The susceptibility of land to desertification is based on the current climate, relief, and the state of the soil and natural vegetation. From there, the occurrence of natural processes such as soil erosion and other processes affect the land. However, the addition of destructive human activity is the main cause of desertification. According to the Food and Agriculture Organization of the United Nations, the process can be held accountable by one or multiple of the following human activities:
♢ cultivation of soils that are fragile, or exposed to erosion by wind or water;
♢ reduction in the fallow period of soils, and lack of organic or mineral fertilizers;
♢ overgrazing - often selectively - of shrubs, herbs and grasses;
♢ over exploitation of woody resources, in particular for fuelwood;
♢ uncontrolled use of fire for regenerating pasture, for hunting, for agricultural clearing, or for settling certain social conflicts;
♢ agricultural practices that destroy the soil structure, especially the use of unsuitable agricultural machinery;
♢ agricultural practices that result in the net export of soil nutrients, leading to loss of the soil fertility, such as cash-cropping;
♢ diversion of rivers to create irrigation schemes; or
♢ irrigation of soils prone to salinization, alkalization or even water logging.
The depletion of soil fertility can also be traced to the interference by nomadic peoples, increase in population and livestock, factors affecting erosion rate (rainfall, wind, solar radiation), reductions in percolation of soil due to livestock hooves, and to a lesser extent, droughts.
A well known example of desertification is the Dust Bowl that swept the Great Plains and most of America in the 1930s. Improper farming practices that were harmful to the soil affected the natural balance of the land. In 1932, a cycle of drought in the Plains began was noticed. The combination of drought and poor soil status lead to the creation of the Dust Bowl, forcing millions of people to leave their homes and livestock for healthier living conditions.
The same effect the Dust Bowl had on the people of the 1930s can be seen happening around the globe today. Unlike developed countries, developing countries do not have the capability to plant trees at nearly the same rate they are being torn down. The lack of steady tree regeneration leads to heavy desertification, especially in areas undergoing constant erosion.
Raising awareness of desertification and its devastating effects is one of the main solutions to the problem. Because the issue is heavily attributed to human practices and interactions, and the solution clearly lies in the hands of the cause, educating people can stop desertification from occurring. In addition to the spoken solution, action can be immediately taken. Planting strips of trees to trap soil and prevent heavy erosion around the fertile environments bordering deserts will save them from becoming unusable. A wall of trees being planted called the "Green Wall" in northeastern China will eventually stretch farther than the famous Great Wall of China, to protect still active areas bordering desert lands that have already suffered from desertification.
Food and Agriculture Organization of the United Nations (1993). Sustainable development of drylands and combating desertification. Retrieved from http://www.fao.org/docrep/v0265e/v0265e00.htm
United States Geological Survey (1997). Desertification. Retrieved from http://pubs.usgs.gov/gip/deserts/desertification/
The cause of desertification is the result of several discrepancies to the very fragile ecosystem at hand. The susceptibility of land to desertification is based on the current climate, relief, and the state of the soil and natural vegetation. From there, the occurrence of natural processes such as soil erosion and other processes affect the land. However, the addition of destructive human activity is the main cause of desertification. According to the Food and Agriculture Organization of the United Nations, the process can be held accountable by one or multiple of the following human activities:
♢ cultivation of soils that are fragile, or exposed to erosion by wind or water;
♢ reduction in the fallow period of soils, and lack of organic or mineral fertilizers;
♢ overgrazing - often selectively - of shrubs, herbs and grasses;
♢ over exploitation of woody resources, in particular for fuelwood;
♢ uncontrolled use of fire for regenerating pasture, for hunting, for agricultural clearing, or for settling certain social conflicts;
♢ agricultural practices that destroy the soil structure, especially the use of unsuitable agricultural machinery;
♢ agricultural practices that result in the net export of soil nutrients, leading to loss of the soil fertility, such as cash-cropping;
♢ diversion of rivers to create irrigation schemes; or
♢ irrigation of soils prone to salinization, alkalization or even water logging.
The depletion of soil fertility can also be traced to the interference by nomadic peoples, increase in population and livestock, factors affecting erosion rate (rainfall, wind, solar radiation), reductions in percolation of soil due to livestock hooves, and to a lesser extent, droughts.
A well known example of desertification is the Dust Bowl that swept the Great Plains and most of America in the 1930s. Improper farming practices that were harmful to the soil affected the natural balance of the land. In 1932, a cycle of drought in the Plains began was noticed. The combination of drought and poor soil status lead to the creation of the Dust Bowl, forcing millions of people to leave their homes and livestock for healthier living conditions.
The same effect the Dust Bowl had on the people of the 1930s can be seen happening around the globe today. Unlike developed countries, developing countries do not have the capability to plant trees at nearly the same rate they are being torn down. The lack of steady tree regeneration leads to heavy desertification, especially in areas undergoing constant erosion.
Raising awareness of desertification and its devastating effects is one of the main solutions to the problem. Because the issue is heavily attributed to human practices and interactions, and the solution clearly lies in the hands of the cause, educating people can stop desertification from occurring. In addition to the spoken solution, action can be immediately taken. Planting strips of trees to trap soil and prevent heavy erosion around the fertile environments bordering deserts will save them from becoming unusable. A wall of trees being planted called the "Green Wall" in northeastern China will eventually stretch farther than the famous Great Wall of China, to protect still active areas bordering desert lands that have already suffered from desertification.
Food and Agriculture Organization of the United Nations (1993). Sustainable development of drylands and combating desertification. Retrieved from http://www.fao.org/docrep/v0265e/v0265e00.htm
United States Geological Survey (1997). Desertification. Retrieved from http://pubs.usgs.gov/gip/deserts/desertification/
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