Gas Tension Device
Gas Tension Device (GTD) instruments measure total dissolved gas pressure. The total dissolved gas pressure in seawater is the sum of the partial pressures of all dissolved gases. The GTD works by equilibrating a small volume of air trapped behind a semi-permeable membrane that is resistant to seawater. When the air sample is isolated from hydrostatic pressure, the measured pressure is solely from the gases in the seawater. This internal pressure is measured using a very stable pressure sensor.
Using the total pressure of all gases, the partial pressure of nitrogen is estimated by subtracting the partial pressure of oxygen (and by making some assumptions for other gases such as CO2).
Individual instruments of the above category, which are (or have been) connected to our observatories. Click an instrument for detailed information.
|Pro-Oceanus GTD 24-36-07||Marine Technology Centre|
|Pro-Oceanus GTD Pro 24-036-08||Marine Technology Centre|
|Pro-Oceanus GTD Pro 36-326-06||Saanich Inlet Central Node|
|Pro-Oceanus GTD Pro 38-502-15||Marine Technology Centre|
|Pro-Oceanus Hurricane GTD 2807742||Expedition - Field Maintenance|
Click the instrument categories below for descriptions and lists of instruments belonging to that category.