Geoecology Sample Biomes

karaokeman

Could someone let me know what extra points I could add to these essays for full marks. I need to get my head around them for friday and remember what i'll need for 80 marks.

Qn.16 With reference to one soil type you have studied, examine how parent material, climate and organic matter influence the soil

The soil I have studied is oxisol. Oxisol is a tropical red soil (TRS), which is found in the biome I studied. The biome I am studying is the tropical rainforest (TRF). This type of forest is common in the Amazon River Basin of Brazil in South America. The factors that influence the soil are climate, parent material, organic matter and living matter. These soils are mainly red due to the presence of iron oxide (IO). Many of these soils are over 100 million years old.

The climate of the TRF's often causes problems for oxisol. In many parts of Brazil the border between the TRF's and non-forest areas reaches precipitation of about 1500mm. In addition to this rainfall often reaches an average of 50-260 inches a year. With heavy amounts of rainfall comes leaching. The rainwater washes away many of the nutrients that are contained in oxisol. Such nutrients may include minerals such as phosphorus, calcium and potassium. It is now accepted that oxisol and other TRS's are not very good soils. They are devoid of nutrients needed for plant growth and cannot provide a suitable ground for many types of vegetation. Various types of trees within the TRF's have root systems grown slightly above the soil. This is mainly due to the lack of nutrients in the soil and the fact that many of these trees will recieve better growth conditions from precipitation and tempearture levels than they will from the minerals within the soil. TRF's are generally very hot with temperatures reaching highs of 94 degrees farenheit and dropping as low as 68 degrees farenheit. This however does not help the soils in many ways because their nutrition relies on nutrients, which they don't have due to leaching. More weathering occurs in TRF's than most other parts of the world. It is a major cause of soil thickness, which is common to much of the oxisol found in TRF's. Heavy rainfall may often occur when deforestation takes place and the soil surfaces are exposed. This creates a run-off effect and is one of the major causes of soil erosion in TRF's. Additionally average precipitation is expected to be between 77 and 88%.

Similarly the parent material conveys evidence that oxisol is a poor soil. Many types of plants contain the soil that would be needed by oxisol. However these plants, which are grown mainly on surface level absorb the nutrients and keep them. The plants cannot return any nutrients to the soils, which are heavily leached and devoid of their own nutrients. The plants mainly recieve their nutrients from decomposing organisms that are living beneath the soil. Decomposing organisms like bacteria, fungi and termites break down the nutrients needed by oxisol. These nutrients are absorbed by the decomposing organisms and used as waste material when the decomposing organisms die. These waste materials are then used to benefit the plants. Plant growth is heavily supported by nutrients recieved by decomposing organisms. A hardpan forms when oxisol becomes waterlogged. The only nutrient that is not leached from oxisol is iron. As the iron is exposed to oxygen in the air, oxidation occurs. The accumulation of humus sometimes helps plants that cannot take in any nutrients from the soil.

Despite the infertility of oxisols within the TRF biomes, there are some more rare fertile soils in South America. The more fertile soils however are the ones with younger substrates and come from volcanic origin. Oxisol is infertile due to the lack of new minerals in the soil.
The top section of the oxisol soil is a layer known as topsol. This however is very shallow due to vast amounts of rainfall and the process of leaching, which is heavy in oxisol. Topsol is about one-two inches (2.5-5cm) deep.

Laterization is another common process that occurs within oxisol. This involves a layer of iron, which builds up as a result of leaching and rapid weathering. The formation is development of latosols and red soils. The areas where this is most common are areas of high rainfall and high temperatures. Bauxite may also be produced by the process of laterization. This is the accumulation of vast mineral deposits that remain on the layer of soil.

Due to living matter within the TRF's it is commonly agreed that the TRF is a completely different ecosystem to many other parts of the world. Though scientists once believed oxisol was fertile soil, they now know it is not. And unlike many soils in the northern hemisphere the high amount of vegetation absorbs nutrients essential for the oxisol. Such examples as carbon and other nutrients would be needed for plant growth through the soils. These materials however are absorbed by the vegetation within the TRF's. In addition to this carbon is also absorbed by dead wood and decaying leaves.
　
Qn.17 Discuss how human activities can accelerate soil erosion

There are many ways in which human activities have accelerated soil erosions. Three aspects of soil erosion I will discuss are deforestation, felling and agricultural practices. The biome I have studied is the tropical rainforest (TRF) in Brazil and the TRF I studied is the Amazon River Basin (ARB). I have also studied aspects of the Sahel region in the areas of farming activities. Temperatures in the ARB range from 68 degrees farenheit to 94 degrees farenheit. Annual precipitation levels also go from 1250mm-6600mm a year. Heavy rainfall after deforestation leads to exposed soils, which are then prone to erosion. Average rainfall is expected to be between 77 and 88%. The soils in TRF's are usually tropical red soils (TRS). These soils are red due to the presence of iron oxide (IO).

Deforestation is the first major process involved with soil acceleration. Many humans cut down trees to make products and for making paper. However these trees also hold the soil together. Without the trees the TRF's would lack much of the vegetation they still have. As the number of TRF's has declined from 2.6 billion hectares in 1800 to 1.5 billion hectares today, this results in a slower rate for plant growth. The eroded soils once deforestation occurs are vulnerable to heavy equatorial conditions just north of Brazil. It is also in these areas of close proximity to the equator (about 10 degrees both north and south) that heavy precipitation occurs. With high rainfall levels comes a higher rate of soil erosion and flash flooding. The nutrients from the soil are leached away by heavy amounts of rainpour. Nutrients such as potassium, phosphorus and magnesium are washed away.

The high levels of deforestation also result in the topsol of many of these soils being eroded. The topsol is the top section of the soil containing the most humus. The lack of humus from dead plant and animal matter causes huge problems for plant and animal growth. This layer of topsol is only 1-2 inches deep (2.5-5cm), which is not enough as deciduous trees are more reliant on deep soils to experience proper growth.
Felling is another process whereby humans interfere with soil erosion. Humans may use saws to cut down tall trees. Felling has the same result as deforestation. It leaves the soils without any cover and exposes them to weathering and erosion. This in turn results in soil erosion and soil exhaustion when the soils are overworked or overgrazed.

Farming activities greatly affect soils in both the Sahael region and the ARB. Overgrazing may occur in the Sahael region when too many animals are grazed on any one piece of farmland. The high population densities in regions like this mean there will be more farmers and greater numbers of cattle and goat. Their hooves compact the soil, leading to destruction of the soil structure. For this reason the soil may be more easily blown away. Such processes can result in desertification. Overcropping also occurs when the land is overused for tiliage. This is the case in the Sahel region where there is an increased demand for food and the land cannot be left without any crops. The soil, which is overworked and becomes deplete of its nutrients becomes dry and dusty. It is easily eroded and very infertile.

Farmers are an important source of human interference towards soil erosion. Many farmers use chemicals such as fertilisers and pesticides. These chemicals cause run-off as does proceeding levels of rainfall. Once these nutrients are washed away and seep into lakes and rivers there is no way they can return to the soil. Many of these farmers overgraze the soils. The farmers who graze the soils wish to provide a guaranteed supply of food to meet the needs of a world population. To do so many of the rainforest areas are cleared and the farmers intend to replace them with farmland. Heavy machinery is used to graze these soils, but the farmers fail to realise that these soils are infertile, which is only a recently accepted belief. Much of the farmland replacing TRF's is proposed by multinational companies (MNC). These MNC's then face conflict with the Brazillian government who are aware of the infertility of soils.

Qn.18 Asess how biomes have been altered by human activity

There are many ways biomes have been altered by human activity. The main processes are felling, deforestation, agricultural practices and industrial impacts. The biomes I have studied are the Irish forest and the Tropical Rainforest (TRF) in the Amazon Riber Basin of South America.

Irish biomes have mainly been impacted by the arrival of Neolithic settlers. Over 10,000 years ago Ireland's forests were affected by the domestification of animals. The settlers spread and started the process of deforestation where they cut down Irish trees. Many of the trees and vast areas of woodland within pre-Christian Ireland were replaced and used for farmland and housing instead. However many crops failed to strive as the processes of deforestation and felling also led to soil erosion. Without the trees there was very little to support the soils, which became infertile as a result. The soils without these trees were exposed to weathering and erosion. Vast amounts of rainfall heavily affected the soils. The soils became deplete of large amounts of humus. The shallow soils failed to support the vast range of Ireland's plants and animals. The infertility of the soils meant that no crops could be grown as a result and the farmers had to use fertilisers to artificially support the soils.
In 1922 it was predicted that about 1% of land in Ireland was covered by forests. Many of the forests were confined to massive housing estates. This is due to the vast deforestation that occured through the arrival of settlers. In addition to loss of woodlands, high amounts of Irish elk and native red Deer were lost. The most significant effect of deforestation on Ireland was the loss of deciduous trees. Deciduous trees take 80 years to grow so this was an irreplacable loss. Many plants and animals who lived in the Irish forests were also affected by deforestation as their natural habitat was destroyed.

As Irish forests were affected heavily by human activity so were the TRF biomes. The TRF is the world's largest biome. It contains over 15 million species of plants and animals. TRF's however have been altered by human usage. In 1800 there was an estimated 2.9 hectares of TRF's worldwide. However this number has declined to 1.5 billion in the present time. Asia has also lost a third of its TRF cover between the years 1960-1980. This has mainly been caused by felling, which occurs because of human activity. Felling has reduced the number of trees in TRF's. The cutting down of trees has led the soils more vulnerable to sil erosion. The soils of the TRF, which are mainly tropical red soils become devoid of their nutrients. These soils have their red colour due to the presence of iron oxide (IO). Felling has led to plant and animal extinction in the TRF's. These animals develop special adaptations to the biome and its destruction is like the destruction of their natural habitat. Felling has impacted on bio diversity. Bio diversity refers to whether or not there is enough pollinators to ensure survival of each species of plant and animal. The animals of TRF's mainly depend on staggered blooming/fruiting of rainforest plants, which provide them with a year-long supply of food.

Felling has also affected the vast range of trees, which occur in TRF's. Examples of such include mahogany, tweek, sandalwood and rosewood. Many of these trees take 60 years to grow enough for timber usage. This has been a major effect of felling. The sustainability of TRF's has also been affected by felling on a large scale. Much of the land area used by TRF's is replaced by farmland. The farmers recieve greater profit from the land that was used for farming purposes. It has been reported that 2000 trees are cut down every minute in the world's rainforests. Many of these trees once cut down lead their soils vulnerable to soil erosion. Soil erosion is heavily accelerated by weathering and erosion and the vast amounts that occur 10 degrees north and south of the equator where Brazil's TRF's are mainly located. The deep soils become shallow and the already-shallow soils disappear leading to a desert-like biome. Many of the soils are worked by multinational companies (MNC's). These soils become depleted of their nutrients by large scale felling and extensive use of farmland machinery.

It is expected by 2050 that due to heavy acricultural practices, Brazil will lose 40% of its current forest cover. This is due to heavy workloads undertaken by farmers where the TRF's were originally located. These lands cleared of their forest area are used by farmers as they hope to provide a guaranteed supply of food to meet the needs of a world population. The overuse of chemicals like pesticides and fertilisers on these farmlands leads to soil exhaustion. The soils fail to supply the farmer's crops with the nutrients needed to fill such ambitions. The soils are constantly overworked. Another problem with heavy chemical use is the run-off effects. Many of these chemicals seep into the soil and lead to leaching, which when the chemicals reach hardpan affects the fertility of these soils. The chemicals also run off into the lakes, rivers and coastlines. This increases acidity levels and it affects many of the species of fish and other water-based organisms living within the biome. Extinction of species becomes a massive problem as many of these organisms die as a result. Much of the farmland is also extended and replaced by roads. This heavily affects the area of Brazil covered by TRF's. The biomes are affected as they become smaller and smaller. Habitats for many animals and plants are destroyed and soils are left vulnerable to weathering and erosion. The corncake in Ireland has almost disappeared due to heavy agricultural usage.

Industrial development is another heavy impact made by humans on biomes. Many developing industries require high levels of charcoal. Charcoal is wood, which is burnt slowly and it is attained by constant industrial manufacture of forest materials cut down by humans. The use of chemicals on the land occupied by TRF's has also led to higher acidity levels. Acid rain occurs due to the increase in greenhouse emissions. Acid rain weakens much of the world's forest cover. In Sweden acid rain is a massive problem and many of its ecosystems have been destroyed as a result. Biomes have also been affected by global warming. Most biomes in western Europe have been destroyed and an expected rise of 8 degrees celcius in Spain will cause much of its natural vegetation to disappear. Many of Spain's coniferous forest biomes have been damaged by acid rain. The river ecosystems have been damaged by water pollution and this has caused many species to disappear. Large-scale loss of low-lying land such as Bangladesh is also expected with the current rise in sea levels.

Thanks:D

biggaman

wish I could give you a hand man but they look pretty good to me.. just bumping it up so it doesn't get lost, might have more of a chance of getting a bit of valuable input!

karaokeman

I think I got 62 marks for the first essay, 56 for the second and 66 for the third.
So as far as I remember all 3 are B standards but I would love to bring them up to an A because I know I'm bound to forget some of this in the exam.