449
Processes in the Oceans
linear correlation with SiO 2 and reached levels as high as 100 μM in seawater when the
area was clear- cut of the tube worms and other organisms.
The scanner system developed by Johnson, Beehler, and Sakamoto- Arnold (1986) has
been used to measure the properties of the plumes coming from the vent systems. Their
results for temperature, light attenuation, iron, and manganese are shown in Figure 10.39.
They have used the measurements of Fe(II) and Mn(II) in the waters as a way of dating the
plume. The Fe was rapidly removed from the system because of oxidation with oxygen,
while the Mn(II) was stable in its reduced form. From the known rates of oxidation of Fe(II)
Mg (mmol kg
–1 )
0
10
20
30
40
50
60
K (mmol kg
–1
)
10
15
20
25
Figure 10.26
Potassium concentration as a function of magnesium in vent waters.
Mg (mmol kg
–1 )
0
10
20
30
40
50
60
Rb (µM)
0
5
10
15
20
25
Figure 10.27
Rubidium concentration as a function of magnesium in vent waters.