The opposite of evaporation is precipitation, such as rain, by which water is added to the ocean. Here the ocean is being diluted so that the salinity is decreased. This may occur in areas of high rainfall or in coastal regions where rivers flow into the ocean. Thus salinity may be increased by the subtraction of water by evaporation, or decreased by the addition of fresh water by precipitation.
Normally, in hot regions where the sun is very strong, the ocean salinity is somewhat higher than it is in other parts of the world where there is not as much evaporation. Similarly, in coastal regions where rivers dilute the sea, salinity is somewhat lower than in other oceanic areas.
A third process by which salinity may be altered is associated with the formation and melting of sea ice. When seawater is frozen, the dissolved materials are left behind.. In this manner, seawater directly beneath freshly formed sea ice has a higher salinity than it did before the ice appeared. Of course, when this ice melts, it will tend to decrease the salinity of the surrounding water.
In the Weddell Sea, the densest water in the ocean is formed as a result of this freezing process, which increases the salinity of cold water. This heavy water sinks and is found in the deeper portion of the oceans of the world.
26. This passage mainly tells us about_______.
A. the analysis of the salinity of ocean waters
B. the causes of the variation in oceanic salinity
C. the importance of the changes in oceanic salinity
D. the different forms of salts in ocean waters
27.It can be known from the passage that increase in the salinity of ocean water is caused
by______.
A. melting of sea ice B. precipitation
C. evaporation D. supplement of salt
28.Which of the following is not the cause of the decrease in the oceanic salinity?
A. Precipitation. B. Rain and snow.
C. Formation of ice. D. Addition of water by rivers.
29.Which of the following statements is TRUE according to the passage?
A. Oceanic salinity has great effect on sea life.
B. Many factors combine to cause changes in oceanic salinity.
C. The movement of the water is related to the amount of salt.
D. The temperature of the water has much to do with the oceanic salinity.
30.The purpose of mentioning the Weddell Sea is_______.
A. to give an example of cold-water salinity
B. to point out the location of deep waters
C. to make a comparison between hot-water salinity and cold-water salinity
D. to show that the water in the Weddell Sea varies in salinity from place to place
26. B 27. C 28. C 29. D 30. A
GRE词汇:考试词汇出现频率统计表31
GRE词汇:考试词汇出现频率统计表35
新g词汇:implacable考法及近、反义词解析
新gre考试机考填空词汇10
新gre考试新增词汇4
新gre考试机考填空词汇20
新gre考试词汇:形近意近词归纳法
新gre考试机考填空词汇15
GRE词汇:考试词汇出现频率统计表26
GRE词汇:考试词汇出现频率统计表37
gre词汇备考:常见词根词缀整理3
新gre考试机考填空词汇6
GRE词汇:考试词汇出现频率统计表30
GRE词汇:考试词汇出现频率统计表36
新gre考试机考填空词汇1
新gre考试机考填空词汇7
新增gre考试词汇3
新gre考试机考填空词汇17
gre词汇备考:常见词根词缀整理1
新g词汇:tenuous考法及近、反义词解析
新gre考试机考填空词汇16
gre词汇备考:常见词根词缀整理4
gre词汇备考:常见词根词缀整理12
新gre考试机考填空词汇19
新g词汇:perfidy考法及近反义词解析
新gre考试机考填空词汇5
GRE词汇:考试词汇出现频率统计表21
新g词汇:impetuous考法及近、反义词解析
新gre考试:新增词汇3
新gre考试机考填空词汇12
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