Water Quality Profiling

MHL has two Sea-Bird Sealogger CTD Water Quality Profilers which are used for a wide variety of field studies to determine spatial variations in water quality parameters in offshore, estuarine and riverine environments. The two instruments are used to measure the following parameters:

SBE 19-03SBE 25-03
ConductivityConductivity
TemperatureTemperature
PressurePressure
Dissolved OxygenDissolved Oxygen
pHpH
Back-scatteranceBack-scatterance
Chlorophyll
PAR

The nature and purpose of each data collection exercise determines which of these two instruments is deployed. Both instruments can be deployed from the survey vessel by profiling at specific locations or by being towed at a fixed depth along a particular transect.

Instrument Calibration

The conductivity, temperature and pressure sensors are tested at MHL immediately before field deployment by comparing the two Sea-Birds. The dissolved oxygen, pH and backscatterance sensors are calibrated in standard solutions at MHL immediately before field deployment. Chlorophyll readings are calibrated with water samples collected in the field.

Field Data Presentation

The data collected in the field can be presented as plots of individual profiles or as long channel contour plots for each parameter.