Deep Water Probe for In-Situ Measurement of pH in Sediments
A special probe was recently designed and constructed by Idronaut Srl. of Milan, to take pH measurements of the interstitial waters in sea bed sediments at the bottom of the Black Sea.
The probe, which had to operate at a depth of 2500m, was fitted with a 40cm long titanium spigot set into the end of the main instrument housing.
Two pH electrodes, together with a reference cell were interfaced into the system. The primary pH electrode was installed at the end of the spigot, with the second electrode and reference cell being fitted into the lower main probe bulkhead. This second pH electrode, was intended to simultaneously measure the pH of the free flowing sea water.
The probe was mounted onto the sampling block of a multi-cored sampling device. This acted as a seabed lander and was lowered to the seabed before being triggered. Once on the seabed, the coring device was triggered, driving the spigot and pH electrode into the seabed sediments.
pH data were successfully measured and internally stored throughout the whole operation and then downloaded on retrieval at the surface.
The probe can also be operated on-line if required, data being hard-wire transmitted distances of up to 10km using one of Idronaut's data telemetry formats.
Idronaut has also developed a 20 micro-electrode Redox profiler for similar applications. Please ask for separate brochure