also conduct sunrise to sunrise, 24 hour incubations conducted in 1 or 4 L polycarbonate bottles 

 using a light quantity, light quality and temperature controlled on-deck incubator system. These 

 simulated in situ incubations will be conducted on the same day as the P-I studies so that the 

 production measurements will be comparable. The P-I and 24 hour incubation studies will be 

 conducted at discrete stations in coordination with other OMP projects. We will determine 

 euphotic zone integrated primary production values (i.e. mg C m" 2 d' 1 ) with each technique. In 

 conjunction with the incubations we will measure surface distributions and vertical profiles of 

 chlorophyll a and take vertical profiles of photosynthetically available radiation (PAR) and 

 measure daily incident PAR. Another routine measurement we plan to make at each production 

 station and during surface water surveys will be spectral absorption and scattering of light, with 

 special reference to those wavelength bands to be utilized by SeaWiFS. When the SeaStar 

 satellite, which will carry SeaWiFS, is eventually launched, we will be in a position to use our 

 understanding of the spatial variability in spectral attenuation and absorption to provide 

 production estimates at both the 1 and 4 km resolution scales of SeaWiFS images. 



METHODS AND PLATFORMS 



We plan to utilize both simulated in situ 14 C incubation and 'Photosynthetron'- style 

 photosynthesis-irradiance methods in order to measure primary productions. We will then 

 employ various modeling techniques, based on distributions of chlorophyll a and incident 

 irradiance fields, in order to extend our production estimates to larger spatial scales. Our 

 bio-optical studies will be based upon use of various light measurement instruments (e.g. 

 Biospherical Instruments PNF-300 and LiCor irradiance data loggers) and the Wet Labs AC-9 

 absorption and attenuation meter in order to examine those factors which impact the irradiance 

 field in coastal water columns. Each of these approaches requires shipboard studies and 

 deployments. Vessels with suitable deck space for setting up our incubation system (about 5' 

 x 10') and for placement of a radioactive materials laboratory van would be required for us to 

 complete our research objectives. 



STRENGTHS AND LIMITATIONS OF PROPOSED RESEARCH 



One of the strengths of our approach to making primary production measurements is that 

 we would be able to provide independent determinations of C fluxes through the phytoplankton 

 on time scales which are comparable to FRR based estimates as well as on daily scales. In 

 addition we will be able to provide production estimates based on larger remote sensing spatial 

 scales (e.g. at both the 1 and 4 km resolution scales). The accuracy of our production 

 measurements will be dependent on a number of factors. The simulated in situ incubations will 

 be subject to volume and containment considerations and the P-I related measurements will be 

 only as robust as the models upon which they are based. Our studies to date have given us every 

 indication that these two types of incubation techniques provide highly consistent and quite 

 reasonable values of production. One question which has yet to be solved is whether or not the 

 Wet Labs AC-9 can reasonably distinguish between the various seawater components which 



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