453
Processes in the Oceans
10.3 Anoxic Waters
Anoxic basins were first described in detail by Richards in 1965. He defined anoxia as a condition in which no dissolved oxygen is available. This condition can arise in natural waters
when the consumption rate of oxygen exceeds the supply. The consumption is linked to
the oxidation of organic matter by bacteria at a greater rate than the oxygen supply from
the atmosphere. The supply of O 2 below the photic zone is dependent on diffusion and
Mg (mmol kg –1 )
0
10
20
30
40
50
60
Zn (µM)
0
50
100
150
Figure 10.34
Zinc concentration as a function of magnesium in vent waters.
Mg (mmol kg –1 )
0
10
20
30
40
50
60
Na (mmol kg
–1
)
440
460
480
500
Figure 10.35
Sodium concentration as a function of magnesium in vent waters.