MBARI chemical sensor program
Lead Scientist/Project Manager: Ken Johnson

We will continue to develop a suite of chemical sensors for dissolved constituents in seawater. The sensors will be used in a variety of oceanographic studies to demonstrate their utility. Our primary focus in 2000 will be on the continued development of in situ, ultraviolet spectrophotometric (ISUS) sensors. In addition, we will continue the development of solenoid-pumped, submersible chemical analyzers for in situ trace element measurements and for phosphate and silicate analyses.

We believe that the simplicity of direct chemical sensing with ISUS sensors will make this approach the method of choice for measurements of chemicals that absorb light in the UV region (NO3-, NO2-, HS-, DOC). As soon as prototype instruments are available for in situ operation, we intend to begin testing them in collaboration with existing MBARI science projects. For example, we will configure an ISUS system for HS- measurements on either of the ROVs. We have a particular interest in deploying that system for hydrothermal vent and cold seep system research. Initial deployments will be oriented towards exploratory science before we consider long-term deployments.

The system should also be particularly well suited for nitrate measurements during long-term deployments on oceanographic moorings for MOOS. Adaptation of a system for mooring deployments will begin with tests in Monterey Harbor at the MBNMS dock and then on the M1 mooring. We believe the system can be rapidly transitioned to deployments in the equatorial Pacific. The high nitrate concentrations in the equatorial waters make this region particularly well suited for early deployments.

Development of iron, phosphate and silicate sensors using our solenoid pump based system will also be continued. An initial goal will be to place an iron monitoring system on the M1 mooring.

This work is also supported by funding from the National Science Foundation.