the upper 100m, with decreased density at greater depths. Sampling should extend as far as the 

 oxygen minimum, which lies at ~200m over the slope. 



Mooring Study/Support: At least three transects within the OMP study area will be occupied 

 regularly with measurements of oxygen, dissolved inorganic carbon and nutrients. Currently there 

 are 'standard transects' in the Cape Hatteras area at 36.5 °N, 36 °N and 35.5 °N. Station spacing 

 is ~5km, with vertical sampling density of order 5m over the shelf, and slightly less in deeper 

 water. 



METHODS AND PLATFORMS 



Platforms: Research vessels will be the primary platform given the space, power and personnel 

 requirements of the analytical instrumentation required for high-accuracy measurements. 



Methods: At least two of the inorganic carbon system parameters (CT, Titration Alkalinity, pC0 2 , 

 pH) will be measured on discrete water samples in order to characterize the inorganic carbon 

 speciation and allow separation of the effects of metal carbonate vs. organic carbon changes on 

 the total dissolved inorganic carbon concentration. We are developing a high accuracy, dye- 

 based pH measurement for incorporation into BNL's automated SOMMA systems. This may be 

 the most cost-effective and space- and labor-saving approach to the C0 2 system for the OMP 

 program, as it requires only one sample and one analytical instrument. The BNL SOMMAs are 

 also configured to measure salinity to an accuracy of -0.01, which may be adequate for OMP 

 purposes. In the interim, we will make potentiometric measurements of total alkalinity and/or 

 discrete measurements of pC0 2 (GC/FID), in addition to the SOMMA's CT analysis. 



Oxygen will be measured to WOCE accuracy guidelines by Winkler titration. Nutrients 

 (nitrate, phosphate, silicate, nitrite, ammonium) will be measured at sea whenever possible using 

 a Technicon Autoanalyzer system and standard methods. BNL has a long history of making 

 nutrient measurements in the Mid-Atlantic Bight, and overall accuracy is close to WOCE 

 guidelines. 



Note we are not planning to make underway measurements of pC0 2 . We would like to 

 continue collaboration with Drs. Chipman and Takahashi (LDEO), who have extensive experience 

 of underway measurement systems and who have already deployed such systems on several OMP 

 cruises. We have found that collaboration and cooperation between the LDEO 'underway' and 

 BNL 'discrete' programs have been effective to date. 



STRENGTHS AND LIMITATIONS OF PROPOSED RESEARCH 



The scientific goals outlined above are readily achievable assuming suitable resources (e.g. 

 ship-time, personnel), and effective coordination of sampling opportunities within the OMP. BNL 



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