A small shipboard effort will be required to conduct process studies within the moored 

 array. The shipboard spatial sampling scales will be 1 km in the horizontal and 1 m in the 

 vertical. 



METHODS AND PLATFORMS 



Platforms: Moorings are the primary platform required by this project. A total of 16 moorings 

 are proposed. Several moorings will be enhanced with ancillary sensors to study photosynthesis, 

 biophysical interactions, and air-sea exchange of gases. Mooring cruises will be required to 

 deploy and recover instrumentation. 



Methods: Dissolved oxygen measurements can be used to study the carbon cycle because many 

 of the biogeochemical processes that alter dissolved carbon dioxide stoichiometrically alter 

 dissolved oxygen. The stoichiometry of photosynthetic carbon fixation is rigid: one mole of 2 

 is produced for each mole of C0 2 reduced. Similarly, the biological oxidation of organic carbon, 

 (CH 2 0) n + 2 = C0 2 + H 2 0, consumes dissolved 2 and produces dissolved C0 2 . The OMP 

 must rely on moored measurements of dissolved oxygen to describe the in situ oxidation and 

 reduction of carbon in the water column because there are no sensors capable of making moored 

 measurements of dissolved C0 2 . 



An oxygen array will be designed to measure community metabolism. Current 

 measurements and measurements of horizontal gradients across the array will be used to partition 

 the local 2 changes into biological and physical components. The biological change at night 

 will be defined as community respiration and biological change during the day will be defined 

 as community production-community respiration. This simple approach will occasionally fail 

 near the surface unless the array is instrumented to provide good estimates of the air-sea 

 exchange of gases. 



Models of the Liss-Merlivat genre will be applied to estimate the air-sea gas transfer rate 

 as a function of wind speed and sea state. More process-oriented models will be used if the array 

 is instrumented to measure physical processes in the marine boundary layer. The local air-sea 

 gas exchange will be estimated using the measured concentrations of gas across the interface and 

 the estimated transfer rates. 



Photosynthesis will be studied as a process. FPvR fluorometers will be deployed on 

 several moorings to independently estimate photosynthesis from stimulated fluorescence. Others 

 projects will use shipboard FRR fluorometers to study the control of photosynthesis and 

 contribute to the analysis of the moored FPvR fluorometer data. 



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