Name_______________________________ Class_____________________ Date
Profile
of a Tropical Ocean
Tropical ocean waters have certain physical characteristics,
which include temperature and salinity. These two characteristics are
influenced by variables that act on the ocean waters. The variables include
amount of sunlight received, proximity to the equator, and seasonal effects
associated with precipitation and with the discharge of major river systems
thousands of kilometers upstream. In addition, temperature and salinity depend
on whether the waters are on or below the ocean surface.
Ocean water is 96.5 percent pure water and 3.5 percent
dissolved solids, such as salt, and dissolved gases, such as oxygen. The
amounts of these dissolved substances remain relatively constant. The salinity
of ocean water is measured in terms of parts (solid material) per thousand of
ocean water.
Water is considered the
universal solvent. It can dissolve most substances, if only in very small
amounts. Because some substances are very soluble in water, their concentration
in the oceans of the earth is quite high. Approximately 95 percent of the
dissolved solids in ocean water are six elements: chlorine, sodium, magnesium,
sulfur, calcium, and potassium. The salts in ocean water come from the land
and, to a lesser extent, from the evaporation of the ocean water.
Table 1
Salinity in the Warm Tropical Waters Off
the Coast of Florida
|
Depth (meters) |
Parts
per Thousand |
|
|
Minimum |
Maximum |
|
|
0 |
34.40 |
35.98 |
|
50 |
34.77 |
36.20 |
|
100 |
36.20 |
37.00 |
|
150 |
36.52 |
37.20 |
|
200 |
36.50 |
37.10 |
|
250 |
36.40 |
36.97 |
|
300 |
36.20 |
36.80 |
|
350 |
35.93 |
36.60 |
|
400 |
35.67 |
36.35 |
|
450 |
35.43 |
36.09 |
|
500 |
35.23 |
35.78 |
|
550 |
35.07 |
35.53 |
|
600 |
34.92 |
35.33 |
|
650 |
34.88 |
35.22 |
|
700 |
34.83 |
35.10 |
|
750 |
34.80 |
35.03 |
|
800 |
34.80 |
34.97 |
|
850 |
34.83 |
34.93 |
|
900 |
34.87 |
34.93 |
|
950 |
34.90 |
34.97 |
|
1000 |
34.97 |
35.00 |
1.
What is the minimum salinity level at the ocean surface?___________________________________________
What is the maximum salinity level at the ocean surface?__________________________________________
2. What is the
difference in salinity between the minimum and maximum levels at sea level?
3.
What is the minimum salinity at a depth of 1000 meters?
How does it differ from the maximum salinity at the same
depth?
4.
How does the minimum salinity level vary between sea level and a depth of 1000
meters?
What
might account for this difference?______________________________________________________
The dissolved gases that warm ocean waters contain are mostly
oxygen, carbon dioxide, and nitrogen. The concentration of these gases depends
on their concentration in the atmosphere, their solubility, and the temperature
and salinity of the ocean water. Table 2 Dissolved Oxygen in the
Warm Tropical Waters Off the Coast of Florida
|
Depth (meters) |
Milliliters
per Liter |
|
|
Minimum |
Maximum |
|
|
0 |
4.32 |
5.41 |
|
50 |
4.31 |
5.25 |
|
100 |
4.18 |
5.26 |
|
150 |
3.96 |
4.91 |
|
200 |
3.88 |
4.71 |
|
250 |
3.90 |
4.42 |
|
300 |
3.92 |
4.29 |
|
350 |
3.79 |
4.25 |
|
400 |
3.50 |
4.13 |
|
450 |
3.17 |
3.95 |
|
500 |
3.02 |
3.71 |
|
550 |
2.92 |
3.58 |
|
600 |
2.90 |
3.46 |
|
650 |
2.92 |
3.24 |
|
700 |
2.92 |
3.33 |
|
750 |
3.00 |
3.37 |
|
800 |
3.08 |
3.50 |
|
850 |
3.25 |
3.63 |
|
900 |
3.37 |
3.83 |
|
950 |
3.58 |
4.28 |
|
1000 |
3.78 |
4.30 |
The most abundant gas dissolved in ocean water is nitrogen. It
is of little importance to the plant and animal life in the earth's oceans,
however. Oxygen enters ocean water through the process of photosynthesis, which
is carried out by green plants in the ocean. Oxygen also enters the water from
the atmosphere and from the rivers emptying into the ocean.
5. In what
units is the amount of oxygen in ocean water measured?
6. At which
level in the ocean is the amount of dissolved oxygen the greatest?
7.
Scan the columns that show the amount of dissolved oxygen in ocean water. What
happens to the amount of dissolved oxygen between sea level and a depth of 1000
meters?
8.
What might account for this variation in the amount of dissolved oxygen in
ocean water?
Solar energy and the properties of water itself determine the
temperature of ocean water. Some scientists estimate that absorption of light
energy accounts for more than 99 percent of the heat entering the sea. Only a
small amount of the heat in the sea comes from the heat in the earth's
interior. The amount of heat entering the sea is frequently equal to the amount
of heat leaving the sea through the process of evaporation. Winds blowing over
the ocean waters also cause the waters to cool off and evaporate. The range of temperatures in the ocean is one
of the factors that causes ocean currents and influences the location of marine
organisms. The temperature of ocean water, like the salinity, remains fairly
constant. This consistency in temperature maintains a balance in marine life
and exerts a steady influence along the shoreline of neighboring land areas.
9. What factors influence the temperature of ocean water?
10. How does the
temperature of the tropical ocean water influence people living in Florida?____________________
Table
3 Temperature in the Warm Tropical Waters Off the Coast of Florida
|
|
Temperature
(°C) |
|||||||||||
|
Depth (meters) |
Jan |
Feb |
Mar |
Apr |
May |
Jun |
Jul |
Aug |
Sep |
Oct |
Nov |
Dec |
|
0 |
26.5 |
26.2 |
26.2 |
26.5 |
27.5 |
27.9 |
28.2 |
28.4 |
28.8 |
29.2 |
28.6 |
27.6 |
|
10 |
26.5 |
26.2 |
26.2 |
26.5 |
27.5 |
27.9 |
28.2 |
28.3 |
28.8 |
29.0 |
28.6 |
27.5 |
|
20 |
26.5 |
26.2 |
26.2 |
26.3 |
27.5 |
27.9 |
28.1 |
28.3 |
28.6 |
29.0 |
28.6 |
27.5 |
|
30 |
26.4 |
26.2 |
26.1 |
26.3 |
27.3 |
27.8 |
28.1 |
28.2 |
28.6 |
28.8 |
28.7 |
27.7 |
|
40 |
26.3 |
26.2 |
25.9 |
26.5 |
27.3 |
27.8 |
28.1 |
28.0 |
28.4 |
28.8 |
28.8 |
27.9 |
|
50 |
26.2 |
26.2 |
25.8 |
26.5 |
26.7 |
27.5 |
27.9 |
27.9 |
27.5 |
28.7 |
28.4 |
27.6 |
|
60 |
26.0 |
26.2 |
25.7 |
26.4 |
26.3 |
27.2 |
27.4 |
27.6 |
27.0 |
27.9 |
27.6 |
27.4 |
|
70 |
26.1 |
26.2 |
25.7 |
25.8 |
25.8 |
26.6 |
26.9 |
26.8 |
26.6 |
27.0 |
26.9 |
27.0 |
|
80 |
25.9 |
26.0 |
25.4 |
25.8 |
25.3 |
25.9 |
26.2 |
26.0 |
26.2 |
26.3 |
26.3 |
26.0 |
|
90 |
25.6 |
25.6 |
25.5 |
25.3 |
25.0 |
25.4 |
25.8 |
25.6 |
25.5 |
25.5 |
25.6 |
25.5 |
|
100 |
25.3 |
25.5 |
25.1 |
25.0 |
24.6 |
25.0 |
25.2 |
25.0 |
25.1 |
25.5 |
24.7 |
24.9 |
|
150 |
22.3 |
22.9 |
22.8 |
22.8 |
22.0 |
22.0 |
22.6 |
22.0 |
22.8 |
22.9 |
22.5 |
22.0 |
|
200 |
19.9 |
20.0 |
20.1 |
19.8 |
19.5 |
19.7 |
20.2 |
20.1 |
20.0 |
20.3 |
19.7 |
19.5 |
|
250 |
18.0 |
18.1 |
18.3 |
17.9 |
18.2 |
17.9 |
18.1 |
18.0 |
18.2 |
18.4 |
17.8 |
17.5 |
|
300 |
16.9 |
17.0 |
16.9 |
16.6 |
16.5 |
16.8 |
16.8 |
16.9 |
17.0 |
17.0 |
16.9 |
16.4 |
|
350 |
16.0 |
15.7 |
15.6 |
15.6 |
14.9 |
15.5 |
15.5 |
15.5 |
15.8 |
15.8 |
15.4 |
15.1 |
|
400 |
14.3 |
14.1 |
14.2 |
14.4 |
13.7 |
14.1 |
14.2 |
14.2 |
14.3 |
14.1 |
14.0 |
14.1 |
|
450 |
13.5 |
12.9 |
12.9 |
13.2 |
12.3 |
12.6 |
13.0 |
12.9 |
13.0 |
13.1 |
13.0 |
12.8 |
|
500 |
12.6 |
11.6 |
11.8 |
11.2 |
11.5 |
10.8 |
11.8 |
11.9 |
12.0 |
12.3 |
11.2 |
11.8 |
|
600 |
10.0 |
10.0 |
9.5 |
9.4 |
9.5 |
9.5 |
9.5 |
9.6 |
9.8 |
9.8 |
9.5 |
10.0 |
|
700 |
7.9 |
8.0 |
7.7 |
7.7 |
7.7 |
8.0 |
7.9 |
8.0 |
8.0 |
8.2 |
7.9 |
8.2 |
|
800 |
6.5 |
6.5 |
6.6 |
6.6 |
6.4 |
6.6 |
6.4 |
6.6 |
6.7 |
6.6 |
7.0 |
6.9 |
|
900 |
5.8 |
6.1 |
5.9 |
5.9 |
5.8 |
5.8 |
5.9 |
5.9 |
5.9 |
6.0 |
6.1 |
6.0 |
|
1000 |
5.2 |
5.3 |
5.3 |
5.3 |
5.3 |
5.3 |
5.2 |
5.4 |
5.2 |
5.3 |
5.3 |
5.3 |
|
11
00 |
4.8 |
4.9 |
4.9 |
4.9 |
4.9 |
4.8 |
4.9 |
4.9 |
4.9 |
4.8 |
4.8 |
4.8 |
|
1200 |
4.6 |
4.6 |
4.7 |
4.6 |
4.6 |
4.5 |
4.5 |
4.6 |
4.5 |
4.7 |
4.6 |
4.5 |
|
1
300 |
4.4 |
4.4 |
4.4 |
4.4 |
4.4 |
4.4 |
4.4 |
4.4 |
4.4 |
4.5 |
4.5 |
4.4 |
|
1
400 |
4.3 |
4.3 |
4.3 |
4.3 |
4.3 |
4.3 |
4.3 |
4.3 |
4.3 |
4.4 |
4.3 |
4.3 |
|
1 500 |
4.2 |
4.2 |
4.2 |
4.2 |
4.2 |
4.2 |
4.2 |
4.2 |
4.2 |
4.3 |
4.2 |
4.2 |
11.
What is the warmest water temperature at sea level?____________________________________________
12. During which
month is the surface water of the ocean the warmest?__________________________________
13. What is the greatest range in ocean temperature from the
surface to a depth of 1500 meters?
14. During which
month(s) is the ocean temperature the coolest?
What would account for these temperatures?
15. What is the
average temperature of ocean water at sea level for the year?
16.
What factors might account for the fact that ocean temperature
does not vary at a depth of 1500 meters?