Study online to Learn about the Environment and how humans influence it.
On a global scale we have what is known as the ecosphere, or biosphere. This consists of three main components: the atmosphere (air), the hydrosphere (water) and the lithosphere (rocks and soil).
The ecosphere is a thin spherical shell (or outer layer) around the earth that consists of:
- a layer of useable atmosphere about 12km thick;
- water found in oceans, glaciers, rivers, ice sheets, streams, aquifers, and as groundwater;
- a thin crust of soil and rocks extending to a few 1000 metres into the earth's interior. In some cases the soil may be only a few centimeters deep.
The ecosphere contains all of the water, gases, and minerals necessary for life on this planet. All of the components of the ecosphere are inter-connected and interdependent. Within the ecosphere all smaller ecosystems are connected with one another by:
- water movement;
- air movement e.g. winds;
- movement of organisms (migrations).
Along with animals and plants, we all live in these ecosystems; and our wellbeing is dependant upon the health of these ecosystems
ACS student comment: "[The course was a valuable learning experience] because it made me aware of environmental information I didn't know, I didn't study for a career improvement, but to learn and implement the information on a daily basis". C. Cadena - Environmental Studies course.
- Describe the binomial system of classifying living things
- Use of keys to identify living things
- Discuss the basics of ecology (the relationships between living organisms and their environment)
- To have a basic grounding in Earth Science and an understanding of global environmental systems
- Understand the Earth’s major environmental problems and how they have come about
- Explain conservation and its importance to individuals and the world
- Identify a range of ways to reduce the environmental impact of ones’ actions at home and globally
There are 6 lessons in this course:
- Living Things
- Classification of plants and animals
- identifying living organisms
- using identification keys
- Basic Ecology
- constituents of ecosystem
- the ecosphere
- the web of life
- habitats and niches
- humans in the environment.
- Global Environmental Systems
- The Earth’s structure
- the atmosphere
- climatic systems
- Gaia theory
- the carbon dioxide cycle
- El Nino.
- Environmental Problems
- loss of agricultural land
- loss of biological diversity
- loss of water
- loss of non renewable resources
- environmental weeds
- the Greenhouse Effect
- Ozone depletion
- ozone as a Greenhouse gas
- The definition and goals of conservation
- the history of conservation
- natural resources (renewable and non renewable).
- Acting Locally: Thinking Globally
- Humans and water
- how to minimize water usage
- energy use in the home
- reducing household waste
- domestic transport and its affect on pollution
- building materials and their environmental impact.
Duration: 100 hours
The Need to Understand and Conserve our Environment
While humans have incredible creative abilities, unfortunately they also have incredible destructive abilities, with many humans thinking that the resources of the planet are there to be plundered for their own good. Conservation is not only concerned with the basic support of human life, but also with the quality of life. Human activities can profoundly change the face of our planet, and can irreparably damage or destroy natural resources upon which human well-being and survival depend.
There are many conservationists, however, who see this idea of conservation as being extremely self-centred, that in fact humans are only just one species on this planet, and that the resources of the planet are not the 'property' of humans, but to all organisms on this planet. Any management and use of the natural resources of the planet must therefore take into consideration the needs (i.e. food, water, shelter, etc.) of not just humans, but other organisms as well. This idea can be carried further, in that many conservationists see that such regard for the needs of other organisms is not only desirable from a moral point of view, but beneficial, even necessary in the long term for human survival on this planet.
With proper management, these resources regenerate and even increase in value and quantity. However, when misused they can be depleted or entirely lost. Renewable resources include plants, animals, soil, water, sunlight and wind.
These are resources such as minerals, fossil and nuclear fuels. These resources are present in fixed amounts, and once they have been used, they do not regenerate. Natural resources are not limited to the land, they include other elements of the environment, such as oceans, tidal lands, and even the air and the atmosphere.
Resources and their use are very intimately interrelated. For example, a forest contains timber, a valuable economic commodity. However, in its natural state, a forest can:
serve as a watershed;
stop or reduce the erosion of soil
provide a habitat for wildlife
provide a recreational area
help lower regional water tables (which can help reduce the likelihood of salinity problems occurring);
affect the local climate (e.g. some tall trees literally have their heads in the clouds – moisture condenses onto their foliage dripping to the ground, thereby increasing the amount of moisture reaching the ground).
The ovious effect of cutting a forest is to destroy the forest, but there are other, often more serious effects that can follow on from that forest destruction (e.g. loss of habitat for wildlife, erosion, etc.). A paramount principle of conservation is that the use of any resource requires consideration of what the impact will be on other resources and the entire environment.
- ensure your skills are up to date, by pursuing further studies or attending professional development activities.
- Keep up to date with what's happening in the field of Environmental Studies. What are the most pressing issues and where is there likely to be more work?
- Join a networking group to meet people who are working in this field..
- Get some experience. Whether paid or unpaid, experience will always make your CV look more impressive and give you some practical knowledge to apply in your interview.
How Much Do You Understand about Rivers and Water Environmemts?
The following is an article by our academic staff.
The Formation of Rivers
The course of a river is the line followed by the river from its source to its outlet. The connected streams that unite into one river form a river system. The line that bounds the drainage area is called the water divide or the watershed.
River systems are not fixed, but are steadily changing and developing. Rivers that follow the natural slope of the land are termed "consequent rivers. Their tributaries that quickly cut valleys along soft strata are termed "subsequent rivers".
Rivers that flowed across a country before mountains were elevated, and where downward erosion has kept pace with elevation, flow in gorges, through mountain ranges. These are termed "antecedent rivers".
The amount of inclination or drop in a river bed determines the rate of flow of the river. The drop is often greatest near the source of the river, normally in mountainous terrain. In the middle part of its course, a river usually flows along the floor of a comparatively flat valley. Approaching its mouth, the river may pass through a broad flood plain that consists of sedimentary material that the river has deposited.
A river is continually lengthening its course by eating backwards with its source streams. In this manner, one rover may tap another, and by capturing its waters become rejuvenated. As mentioned above, a typical river has three characteristic portions:
The Torrential Course
These rivers usually start in mountainous region. In this portion, the river flows down the hillside in a narrow ravine as a mountain torrent, much interrupted by falls. This zone can leave behind large erosion channels through rock.
The Valley Course
In this portion the gradient is gentler and the velocity of flow is less. The river is easily deflected from its course by obstructions and it begins to wind and meander.
The Plain Course
In this portion the river has eroded downwards, almost to sea level, and so it has a gentle gradient and a low velocity of flow. It meanders widely, but its work is mainly constructive in the formation of shoals, flood plains and deltas.
Many rivers have only a torrential course, and in others the plain course has been drowned beneath the sea by depression of the land. In such a case an estuary is formed. In all of its stages, a river carries out transport work, but the amount of material that can be carried in suspension or rolled along the bed depends upon the velocity of flow. A great deal of matter is also carried in solution.
Rivers are among the chief agents that cause the gradual erosion of mountains and other land masses. Rivers are also of great economic importance to the areas through which they form - they serve as sources of water for the irrigation of crops, as arteries of commerce, and as sources of power.
Some rivers, especially those that flow through rainless areas or receive their water only from rains near to their sources, are intermittent and by excessive evaporation, may cease to flow in their lower reaches.
Most rivers have seasonal periods of floods, due either to heavy rainfall or to the melting of snow near to their sources. Rivers in the high latitudes freeze in winter, but the undercurrent generally remains in motion. When the ice on such rivers breaks up in the spring, there are usually heavy floods. In some regions of the earth composed of soluble rock, rivers frequently flow underground.
Water is not lost like soil. The earth will always have the same amount of rain, while soil can be lost forever into the dams and the sea. However, although water cannot be lost, it can be rendered unusable. The collection of silt reduces the capacity to store water and it can increase the evaporation effect. When a dam becomes shallower because of silting, the water depth decreases and it becomes more prone to evaporation.
Evaporation can also cause lack of rain. High heat areas can see rain evaporating before it reaches the ground. A remedy is to provide good ground cover. This reduces the rising heat and the evaporation, allowing rain to reach the ground.
Dams have both positive and negative ecological effects. The positive effects are:
• The flow of the river is regulated, reducing flood damage.
• The flow can be regulated so that it is perennial as opposed to seasonal
• Sediment is deposited in the dam that helps the growth of aquatic plants that remove excess nutrients form the water. The water leaving the dam is thus much cleaner that the water entering.
• The negative effects are:
• The ecological impacts reduce the strong water flow that lessens the river's scouring capacity that in turn can lead to silting of the estuaries.
• When a dam is being created, humans and animals have to be moved.
• The creation of a dam causes the loss of valuable land that could be used for other purposes.
• The creation of large water surfaces can affect the weather of the area and even adjacent areas.
Eutrophication is another problem with dams. The process is triggered of by too many nutrients entering a body of water. The nutrients from sewerage works, industrial effluent and fertiliser impregnated runoff from farm use ‘blooms’ in dams and lakes. These blooms are sudden flushes of algae growth. For example, from time to time the water in the Hartebeespoort Dam turns pea green as the quantity of gelatinous algae build-up. Cattle have died after drinking from the dam poised by blue green algae. Paradoxically, the more life there is in the dam, the more death there is. The dead algae and water weeds sink to the bottom of the dam and begin to decay. In this process they take up oxygen that can result in suffocation of the fish. The result of eutrophication is that the water dies and becomes a swamp, giving off methane gas.
This is not an easy problem to solve. The phosphates and the nitrates come from the outflow of sewerage works. These chemicals are potent fertilisers. The principle of sewerage treatment is to turn the harmful organic wastes into inorganic wastes. Unfortunately the nitrates and phosphates, both inorganic, emerge as by-products. They eventually end downstream and cause a boost in plant life. Eliminating these two chemicals is difficult.
The river catchment or drainage basin is the land from the top of the mountains to the sea shore drained by a single river or its tributaries. This is the catchment area of a particular river.
Catchment areas vary in size. A large river may have a catchment area of several thousand square kilometres, while a small stream's catchment area may be only a few hectares in size. The catchments are separated from each other by watersheds (e.g. the ridge line of hills and mountains).
The biological, physical or chemical characteristics of any river area are determined by the nature of the catchment area and its activities. These activities may be natural or man induced.
Maintaining good ground cover is very important for catchment areas. In those catchment areas that have not been developed by humans, the ground cover, or "vegetation" is still in place. In developed areas this cover may have been removed, and replacing it when possible is essential. Ground cover is important for the following reasons:
• Plants slow down the water as it soaks over the land. This lets the water soak into the ground and replenish the supplies of groundwater. Water seeps from these supplies into rivers, allowing them to flow throughout the year, which is very important for many types of plants and animals.
• Plants significantly reduce soil erosion, because their roots hold the soil in position. This stops it from being washed away. The presence of plants also breaks up the impact of raindrops before they hit the soil. This reduces the erosive potential of heavy rain. The rivers flowing through an undisturbed catchment area are clean and erosion is slow, and generally limited to periods of heavy rainfall.
• Vegetation in wetlands and on banks of rivers is very important. The roots of the reeds, sedges, trees and grasses growing in the wetland and alongside rivers bind the soil of the riverbank, reducing erosion. They also regulate the flow of water, and act as a cleaning/filtering agent.
• In disturbed catchments, where the plant cover has been disturbed by farming, industry and settlements, soil erosion increases. Without the plants the runoff also increases, and the supply of water to the underground sources is diminished because less water soaks into the ground. This is why rivers do not have a continuous supply from the underground sources and flow only in rainy seasons. Much of the deposition of silt in river estuaries is caused by riverbank erosion. When the vegetation on riverbanks is removed, the banks are exposed to the scouring effects of flood waters. These forces scour away the riverbank, allowing the adjacent slopes to collapse.
Urban areas can be defined as “those areas where the ecosystem is significantly modified by dense human settlement and associated activities”. The urban catchment is the surrounding creek or river system into which water drains from urban areas.
Over 50% of the world’s population live in urban areas, thus the effects of urban runoff is a global issue.
• In undisturbed forest about 2% of rainfall runs off the surface into creeks and streams. It may have a bit of debris in it (e.g. twigs or leaves), but is otherwise cool and clear.
• In areas where land is cleared for farming or agriculture, about 14% of water runs off. Clearing land leaves soil exposed, so it is easily eroded. Increased volumes of surface runoff erode river beds and banks, releasing even more soil into waterways.
• In urban regions there are large areas of impermeable surfaces (e.g. paving, roadways, and buildings). Around 85% of surface water runs off from these areas.
o Dirt, litter, oil, garden chemicals & animal wastes are carried with the runoff water into drains and eventually streams, and then estuaries and bays.
o For example in Melbourne, Australia there are an estimated 200,000 side entry drain pits in roadside kerbing, where litter and other debris (e.g. soil, plant matter) can enter the storm-water system.
o With much higher runoff, and large areas of impermeable surfaces there may be less water entering groundwater systems in lower catchment areas, although this may be offset by increases to groundwater as a result of cleared vegetation in upper and middle catchment areas.
Many major cities have two separate water removal systems:
1. Sewerage (this will be directed through treatment systems/plants of some sort).
2. Storm water (rarely passing through any sort of treatment system).
3. The storm water system is designed to move large volumes of water quickly to prevent flooding, but as a result it also collects and transports huge amounts of contaminants. Illegal connections of storm water pipes to sewage pipes can cause overflowing of sewerage through overflow pipes out into the environment (e.g. creeks) which can cause major pollution.
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