2. Soils
2.1. The role of soil in the ecosystem
1) Food and other biomass production.
2) Environmental interaction such as storage, filtering, and transformation i.e. wetlands.
3) Biological habitat for soil organisms.
4) Source of raw materials.
5) Platforms for man-made structures such as buildings, highways, etc.
6) Recycling system for nutrients and organic wastes i.e. decomposition.
7) Nitrogen fixation which is the process of which atmospheric nitrogen is absorbed into organic compounds by microorganisms in the soil.
8) Medium for plant growth by supplying nutrients to plants.
Definitions
Soil erosion: Is the wearing away of topsoil- the nutrient-rich top layer of soil, by the natural physical forces of water and wind or through forces associated with farming activities. Soil erosion reduces cropland productivity and contributes to the pollution of nearby watercourses, wetlands and lakes.
Soil is a non-renewable resource.
Desertification: Without soil and plants the land becomes desert-like and unable to support life.
Runoff: Something that drains or flows off from the land in streams.
The loss of protective vegetation through deforestation, overgrazing, ploughing, and fire makes soil vulnerable to being swept away by wind and water.
The amount of soil the wind and water can carry away is influenced by two factors:
o Speed- The faster the wind or water moves, the more soil it can erode. o Plant cover- Plants that protect the soil and in their absence wind and water can do much more damage.
2.2. Causes of soil erosion
1) Overstocking i.e. the excessive amount of cattle and overgrazing i.e. when cattle’s eat the grass to root level. Therefore a lesser chance of it growing back.
2) Inappropriate farming techniques...
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... larger animals which are then consumed by animals at the top of the food chain.
The impact of climate change on a particular species can rise through a food web and affect a wide range of other organisms.
o Initiation Effects:
Coral bleaching: When coral reefs become stressed, they expel microorganisms that live within their tissues and are essential to their health.
As ocean temperatures warm and the acidity of the ocean increases, bleaching and coral die-offs become frequent and are unable to recover.
o Pathogens, Parasites, and Disease:
Climate change and shifts in ecological conditions could support the spread of pathogens, parasites, and diseases, with potentially serious effects on human health, agriculture, and fisheries.
o Extinction Risks:
Climate change, along with habitat destruction and pollution can contribute to species extinction.
It is an unquestioned fact that the climate is changing. There is abundant evidence that the world is becoming warmer and warmer. The temperature of the global land average temperature has increased by about 8.5 degrees centigrade from 1880 to 2012 (Karr, et al 406). The one or two degrees increase in temperature can cause dramatic and serious consequences to the earth as well as humans. More extreme weather occurs, such as heat waves and droughts. The Arctic Region is especially sensitive to global climate change. According to the data in recent decades, the temperature in the Arctic has increased by more than 2 degrees centigrade in the recent half century (Przybylak 316). Climate change has led to a series of environmental and ecological negative
affects the ecosystem. The land's incline prevents some areas to receive and maintain a water
Coral bleaching happens when there is a decrease of zooxanthellae involved in the symbiotic relationship with their coral host. This also causes a loss of the coral's beautiful colors that sometimes can be seen to human eye. Bleaching leads to death of coral over time. Some causes of bleaching have been tied to salinity of the ocean and sedimentation. The main reasons known to cause severe coral bleaching are climate change and radiation. These two elements are extremely harmful to coral especially when they’re working together at the same time (Fitt et al. 2001).
All over the world coral reefs play an important part in our environment. Not only are the reefs colorful and beautiful to look at but the coral reefs house several different types of fish and other sea creatures. Coral reefs have started to decline over the years due to “climate change, El Nino events, overfishing, pollution and other pressures” (Newnham 1). A healthy coral reef can also collapse due to a natural disaster (Newnham 2). There can be several different reasons why a coral reef has started to decline or has been destroyed.
Coral bleaching is when the tiny algae that lives in the coral which causes it to be bright and colourful, gets so stressed out when the water temperature exceeds the limit that it can handle, which then makes the algae
Coral reefs around the world are in danger. One of the causes is global warming, which has been increasing the temperature of the ocean water resulting in coral bleaching. This essay will focus on damage occurring to the Great Barrier Reef.
Coral bleaching acquired its name from the white color the corals turn after the zooxanthellae leave its host. Zooxanthellae play a vital role for corals by supplying them with photosynthetic products, which are important to their survival and it also gives the coral its color. Over the past several decades the temperature of Hawaiian waters have increased and caused several bleaching events throughout the islands. Aside from temperature changes, bleaching events can be cause by random changes in the environment, which include but are not limited to, an increase or decrease of irradiance, altered quality in the visible range, altered spectral quality in the ultraviolet radiation range, low salinity, sedimentation, infectious diseases, oil contamination, and exposure to toxic materials (Jokiel and Brown 2004). In the case of oxybenzone, corals are most likely being affected by the exposure of toxic materials and, because oxybenzone normally accumulates in the surface of the water, UV radiation range and irradiance decrease. The accumulation of the chemical in the surface can create a barrier that blocks some of the UV light from getting to the corals, which then decreases irradiance and radiation
Imagine a lush underwater place. Beautiful structures colorful animals and places that would never have been thought of before. In reality that's not what it really looks like, really the ocean is a desolate place that is barren like a desert. Many marine species have been lost by as much as 49%.(seeker) A big part of that reason is because of coral bleaching which causes as stated above a decline in species that depend on the coral as there home. Coral bleaching is a serious problem that could cause problems for everyone if we don’t fix it.
Rates of coral calcification on the Great Barrier Reef and many other reef systems around the world have declined by 15-20% since 1990 due to increasing thermal stress (De’ath 2012). It has already been mentioned that the oceans absorb almost all of the excess heat from climate change. This affects coral reef systems in what is known as coral bleaching. The term bleaching refers to the loss of corals’ colors. A coral’s color is the result of the zooxanthellae present.
This website gives a large historical overlook and possible conclusion to the issue of coral reef bleaching. Since the 1980’s episodes of coral reef bleaching and death have occurred almost every year in one or more of the world's tropical or subtropical seas. Bleaching happens in episodes, with the most severe typically accompanying coupled ocean–atmosphere phenomena. Bleaching episodes have resulted in loss of coral
Corals bleach when stresses, including high temperatures, stimulate the coral animal to expel its intra-cellular single-celled plant symbionts, which are characteristic of all reef-building corals and critical to coral health. As the color of corals is determined in large part by the plant cells, the corals appear to bleach.
Climate change is one of the major issues surfacing on Earth over the past century. The earth’s temperature has increased over the years, leading to detrimental effects on the economic and life sources of people, especially that of agricultural production and livestock. The Merriam-Webster online dictionary (2014), defined climate change as a change in global climate patterns apparent from the mid late 20th century. The Intergovernmental Panel on Climate Change, IPCC, (2007) predicts that by 2100 the increase in global average surface temperature may be between 1.8° C and 4.0° C. With increases of 1.5° C to 2.5° C, approximately 20 to 30 percent of plant and animal species are expected to be at risk of extinction. Moreover, the IPCC (2007) purported that climate change has severe consequences for food security in developing countries.
In many parts of the world, ecosystems’ temperatures begin to rise and fall to extreme levels making it very difficult for animals and plants to adapt in time to survive. Climate has never been stable here on Earth. Climate is an important environmental influence on ecosystems. Climate changes the impacts of climate change, and affects ecosystems in a variety of ways. For instance, warming could force species to migrate to higher latitudes or higher elevations where temperatures are more conducive to their survival. Similarly, as sea level rises, saltwater intrusion into a freshwater sys...
Agriculture also leads to soil erosion, both through rainfall and wind. This soil can damage the aquatic ecosystems it ends up in, an...
Can different types of plants prevent soil erosion? Erosion is the wearing away of land by wind and water. It can be caused by frequent and intense rain, high river levels, strong storms and fast moving streams. Erosion can also lead to a variety of environmental issues. Plants are a natural way to help prevent erosion and other environmental issues caused by erosion.