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环境类assignment代写-Why are ocean resources so important for hum--英国论文代写范文精选

2015-11-17 | 来源:51Due教员组 | 类别:更多范文

环境类assignment代写1.Why are ocean resources so important for humans?
According to the attached information:
a. The ocean is one of Earth’s most valuable natural resources. It provides food, as about 200 billion pounds of fish and shellfish are caught each year.It is hard to image that our world without fish and shellfish,especially for the countries nearby sea which regard fish as their main food.
b. Seawater is used as transportation for both travel and shipping. Maritime transport ion is still the main transportation around the world.Because of the physical properties of water conferring buoyancy and limited friction, maritime transportation is the most effective mode to move large quantities of cargo over long distances[1].
c. Additionally, it provides a source of recreation for humans, as well as mined for minerals, including salt, sand, gravel, manganese, copper, nickel, and iron, and drilled for crude oil. Minerals are absolutely essential to life on this planet, and the importance of minerals and trace elements in the functions of living organisms is without question.
d. The ocean is also an increasingly important source of biomedical organisms with enormous potential for fighting disease.
e. Besides these resources provided to humans, the ocean plays a critical role in keeping Earth’s biosphere in balance. It removes carbon dioxide from the atmosphere and provides oxygen through the primary productivity of phytoplankton.
f. Moreover, its ability to store heat allows it to regulate Earth’s climate.

With these few examples, there is no doubt that the ocean plays an important role in Earth’s systems and humans daily life.

环境类assignment代写2.Explain the consequences of over-exploitation of our ocean resources.
Over-exploitation of ocean resources includes overfishing, over using of minerals,excessive mining the oil under the sea.In my opinion,the main aspect of over-exploitation is overfishing.
Overfishing is the removal of marine living resources to levels that can not sustain viable populations. Ultimately overfishing can lead to resource depletion in cases of subsidized fishing, low biological growth rates and critical low biomass levels (e.g. by critical depensation growth properties). For example, overfishing of sharks has led to the upset of entire marine ecosystems[2] .
The exponential growth of human population in last decades has lead to an overexploitation of marine living resources to meet growing demand for food. So traditional fishing methods were not meet the demand of fish resources. The use of modern techniques to facilitate harvesting, transport and storage has accelerated this trend. According to the United Nations Food and Agriculture Organization (FAO) over 25% of all the world's fish stocks are either overexploited or depleted and 52% are fully exploited [3]. Thus almost 80% of the world's fisheries have be overexploited. Although, these estimates are considered rather conservative. Recently, a study showed that 29% of fish and seafood species are becoming extinct (i.e their catch has declined by 90%) and are projected to die out within by 2048, unless immediate action is taken [4]. (51Due责任编辑:BUG)


Overexploitation do not only affect open ocean or pelagic ecosystems, but also coastal and intertidal areas [5]. For example, intertidal limpets in Hawaii , the Azores, Madeira and Canaries have all shown declines, and in the case of the Azores, dramatic population crashes owing to food gathering [6]


3.There are two main questions facing fisheries management in the world:
(a) What is the carrying capacity of the ocean?
(b) How should fisheries resources be divided among people?

Can we solve these questions? Justify your answer.


4.Suggest means for the sustainable use of our ocean resources. Evaluate the merits and limitations of your proposals


Reference

[1] Transportation Modes: An Overview.Authors: Dr. Brian Slack, Dr. Jean-Paul Rodrigue and Dr. Claude Comtois.
[2] Shark Declines Threaten Shellfish Stocks, Study Says", National Geographic News. 29 March 2007.
[3] The State of World Fisheries and Aquaculture (SOFIA) www.fao.org/sof/sofia/index_en.htm
[4] Worm, B. et al. Impacts of biodiversity loss on ocean ecosystem services. Science 314, 787-790
[5] Thompson, R.C., Crowe, T.P, Hawkins, S.J. (2002) Rocky intertidal communities: past environmental changes, present status and predictions for the next 25 years. Environmental Conservation 29(2): 168-191
[6] Hawkins, S.J., Corte-Real, H.B.S.M., Pannacciulli, F.G., Weber, L.C. & Bishop, J.D.D. (2000) Thoughts on the ecology and evolution of the intertidal biota of the Azores and other Atlantic Islands. Hydrobiologia 440: 3-17

 

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