Geoscience Reference
In-Depth Information
Oxygen microelectrode
Microelectrode tips
Shaft of
sensing cathode
Guard silver
cathode
Epoxy
Silver wire cathode
Ag/AgCI anode
Platinum
Soda-lime glass
Schott 8533
glass
Electrolyte
Schott 8533 glass
Platinum wire
Sensing gold
cathode
Silicone rubber
membrane
1 cm
10 µm
Figure 4.2. Diagram of a microelectrode at different magnifications as developed by niels
Peter revsbech, and as used as a standard tool in microbial ecology. redrawn from
revsbech (1989).
under a given area of the mat), we find that these rates are also high. For
example, the depth-integrated rates of oxygen production for the data
shown in
igure 4.3
amount to about 20 millimoles of oxygen produc-
tion per square meter of mat surface per hour. This value is much higher
than the rates found through most of the global ocean, and it is matched
or exceeded only in the most highly productive coastal areas. And in
these mats, all of this oxygen production occurs over less than 1 mm
depth! This is remarkable. Rates of oxygen production and depths of
