1 50 Information Storage and Neural Control 



For energy flux determinations, paired dark and liglit bottles 

 containing water samples from two, six and ten feet were sus- 

 pended at various depths in the water column for twenty-four 

 hours (beginning 0730 EST), and then fixed for Winkler titration. 

 The suspension depths included all combinations of the collection 

 depths: (2,2), (2,6), (2,10); (6,2), (6,6), (6,10); (l0,2), (l0,6), 

 (10,10), where the left member of each pair designates collection 

 depth and the right member suspension depth. Additional dark 

 bottles for (l4,14) and (l8,18) were also included. Production 

 variables were detei mined from the initial and final dissolved 

 oxygen concentrations in the bottles: 



TT = I — d (photosynthesis) 



[23] p = i — d (respiration) 



IT — ,0 = I — i (net production) 



where /, d and / are, respectively, light bottle, dark bottle, and 

 initial oxygen concentrations. The differential oxygen concen- 

 trations were converted to gram calories (gcal) using suitable 

 conversion factors derived from the stoichiometry of the photo- 

 synthesis and respiration reactions. 



Incident solar radiation at the water surface was measured in 

 gcal cm~" by an Eppley 10-junction pyrheliometer installed a few 

 hundred yards from the station, the output of the thermopile 

 being electronically integrated and automatically printed-out 

 every thirty minutes. Extinction coefficients for "white" light 

 were detei mined on samples obtained from the various depths 

 at the beginning and end of each experiment. The optical densities 

 were measured with a Klett-Summerson colorimeter, using a 

 neutral filter. From these values a mean was obtained for the 

 upper ten feet and was employed to estimate the light intensity 

 at any depth. 



Total chlorophyll was assayed by Millipore-filtering samples 

 from different depths, grinding filters and residues with sand and 

 extracting the pigment in 90 per cent acetone (A/^COs-saturated), 

 then Seitz-filtering to remove sand and undissolved millipore frag- 

 ments. Absorbancies were determined with a red filter, and were 

 converted to chlorophyll concentrations by comparison with a 

 standard curve prepared from chlorophyll a. 



