PRINCIPAL 



INVESTIGATOR(S) Michael D. DeGrandpre and Frederick L. Sayles 



Both at: Department of Marine Chemistry and Geochemistry 



Woods Hole Oceanographic Institution 

 Woods Hole, MA 02543 



PROJECT TITLE DEVELOPMENT OF AN AUTONOMOUS C0 2 SENSOR FOR 



MOORING-BASED TIME-SERIES MEASUREMENTS OF 

 SEAWATER pC0 2 



AMOUNT OF FUNDING FY 1994: $86 K 



SUMMARY OF GOALS 



The primary goal of our DOE-OMP research has been to develop a fiber optic sensor for 

 mooring-based measurements of seawater pC0 2 . Specific goals during the initial 2 year funding 

 period were the following : fully evaluate the sensor response characteristics using a wide range 

 of operating conditions (temperature, reagents, flow rates, etc.), develop reliable and reproducible 

 sensor fabrication techniques, design a sensor instrument based on the preliminary studies which 

 minimizes size, complexity and power, test the long-term stability of the sensor both in the 

 laboratory and in the field, and determine the sensor susceptibility to fouling and corrosion. 



Our ultimate objective is to use the sensors to record C0 2 mixed-layer dynamics with high 

 temporal and spatial resolution. This information will quantify the magnitudes of biological and 

 physical forcings on sea surface C0 2 which will lead to a better understanding of the controls on 

 C0 2 fluxes between the air and sea. 



SPATIAL AND TEMPORAL SAMPLING SCALES 



The sensor instrument has been designed to operate on a mooring for up to 3 months at 

 two measurements per hour. We tentatively plan to deploy 2-3 instruments on the heavily 

 instrumented biogeochemical mooring off Cape Hatteras. More instruments may be deployed 

 along the cross-shelf transects depending upon funding and time. The half-hour sampling 

 frequency will enable us to capture short term episodic events over the 3 month deployment. 



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