NOVA

Mountain of Ice

Student Handout

Ice Core Data

Chemicals in the Ice
Sulfate (SO42-)

The sulfate ion has several sources in this Antarctic ice core. The most important of these are marine biological processes and volcanic activity.

  • The sulfate ion produced by marine phytoplankton peaks in the spring. After the dark winter, the hours of daylight lengthen and the sea ice begins to melt and break up. This open ocean environment is ideal for marine phytoplankton growth. As the phytoplankton grow, they release sulfate-rich chemicals into the atmosphere, which in turn get transported by winds over the ice sheet.

  • Another source of sulfate is volcanic eruptions. Volcanoes can spew millions of tons of sulfate into the atmosphere and concentrations can remain high for several years following a large volcanic eruption.

  • The Tambora volcano in Sumbawa, Indonesia, erupted in 1815; acid from that event is believed to have settled in Antarctic ice about 1816-1817. Another unknown volcano erupted in late 1808 or early 1809.


Sodium (Na+) and Chloride (Cl-)
In this Antarctic ice core:

  • Most of the sodium and chloride ion concentrations come from the ocean in the form of sea salt (NaCl).

  • Sodium also has a terrestrial dust source but this only contributes a minute percentage in this core.

  • Chlorine can be given off by volcanic eruptions in the form of hydrochloric acid (HCl).

  • Sodium and chloride ion concentrations usually peak in the winter-spring season; during the winter-spring months the Antarctic wind strength increases and whips the ocean into foam and transports more sea salt ions inland. If many storms occur during a single season there can be several peaks superimposed upon one another.


Ice Core Data
U.S. ITASE-99-1
Latitude: 80.62 S Longitude: 122.63 W

Depth
from top,
in meters

Sodium
(Na+),
in ppb*

Chloride
(Cl+),
in ppb

Sulfate
(SO42-)
in ppb

37.270

16.40

42.63

91.48

37.297

53.14

99.46

96.71

37.324

81.74

140.71

107.92

37.351

50.10

93.78

129.02

37.378

27.99

46.85

203.13

37.405

43.38

69.35

225.60

37.432

82.17

109.37

266.19

37.459

43.40

83.46

264.96

37.486

71.32

115.21

554.33

37.513

54.79

180.34

479.90

37.540

209.26

294.90

768.02

37.567

241.75

328.83

679.31

37.594

68.56

160.46

243.69

37.621

53.20

98.16

280.67

37.648

51.00

93.63

308.64

37.675

37.96

60.38

314.44

37.702

32.42

46.35

295.36

37.729

10.64

20.25

219.09

37.756

16.08

34.28

164.09

37.783

57.75

85.50

162.82

37.810

52.45

85.74

79.41

37.837

30.88

51.17

68.91

37.864

32.45

53.67

61.68

37.891

12.64

32.39

57.15

37.918

44.91

82.84

67.82

37.945

97.03

152.79

87.95

37.972

83.86

136.20

34.01

38.000

22.83

37.84

97.92

38.027

22.96

36.86

95.10

38.054

43.24

63.62

51.29

38.081

54.78

83.29

38.04

38.108

44.26

75.44

31.44

38.135

5.55

13.52

17.32

38.162

5.06

12.37

24.90

38.189

14.81

26.11

41.81

38.216

42.10

64.93

46.09

38.243

40.71

66.41

36.44

38.270

53.17

90.35

59.36

38.297

16.64

46.90

62.55

38.324

39.48

72.02

82.38

38.351

48.87

93.15

69.49

38.378

45.34

82.35

62.39

38.405

122.19

173.73

101.22

38.432

52.43

90.37

74.20

38.459

44.61

69.06

101.28

38.486

54.40

84.59

205.43

38.513

69.42

114.81

273.03

38.540

98.30

142.69

296.44

38.567

98.73

159.80

218.24

38.594

283.47

439.44

225.51

38.621

83.32

166.07

90.38

38.648

33.31

72.26

101.46

* parts per billion (micrograms per liter)



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