UNIT TEN : BIOTA AND THEIR ENVIRONMENT
ECOLOGICAL IMBALANCES
CLASS : 11
ECOLOGICAL IMBALANCES
CLASS : 11
Depletion of Ozone Layer
The ozone is a gas (O3) occurs naturally in earths atmosphere between 10-50 Km. the ozone is considered as both destroyer as well as protector for us.
The ozone as a destroyer
High concentration of ozone reduces crop yield, damage leaves reduces quality of crops. 0.3-ppm ozone causes throat, nose irritation, 1.3 ppm causes fatigue, and 9 ppm causes several pulmonary diseases.
Ozone as protector
The ozone layer prevents UV rays coming from sun to the earth. 10% reduction of O3 increases UV radiation on the earth by 2%. It causes skin cancers. 10% reduction of ozone leads 20-30 % increase skin cancer. Only in America 6000 people per year die by skin cancer
What is Ozone?
The accumulation of oxygen in the atmosphere due to photosynthesis by green plants resulted in the formation of an ozone layer high in the earth atmosphere. The ozone layer forms a very protective covering around the earth's atmosphere. It prevents the UV rays present in the solar radiations from reaching our atmosphere, thus saving us from the extremely damaging effect of UV rays. The Ozone layer depletion is the process of destruction or using up of ozone in the stratosphere by different pollutants making the ozone layer thinner. when ozone is depleted there would be certain zones or holes without ozone through which UV radiation enter the earth causing various problems such zone or hole called ozone hole.
Cause of Ozone depletion
Chlorofluorocarbon (CFC) and nitrogen oxides produced by the air craft, satellites, industries, and fertilizers release in atmosphere and specially CFCs stays for five to six years in the atmosphere. During this period, it gradually releases chlorine, which reacts with ozone and causes damage to it.
CFCs…………………..Cl + C-compounds O3 + Cl………………...ClO + O2
ClO + O………………Cl + O2
Effect of ozone layer depletion
Change of environment, due to more UV radiations entering in the earth rises to a certain degree, which can lead to the failure of rainfall. When the ozone layer is depleted, harmful UV radiations may cause skin cancers. A higher UV radiation reduces the photosynthesis, causes necrosis, leaf drop, the growth is altered, the chlorophyll content wills decrease, harmful mutation of plants, and animals, reduce the productivity of the crops, decrease in the number of phytoplankton and zooplankton, and harms fishes and other aquatic life.
Tags:
Biology