PRIMARY PRODUCTIVITY (field work)

Using 500 ml sterile, acid washed polycarbonate flasks, add 325 ml to a light flask and 325 ml to a dark flask

Using 14C Hamilton Syringe, add 81 ul 14C (0.5 uCi/ml) to the light flask and start a watch. Immediately withdraw 1x 100 ml sample and filter onto Millipore GS filters. Rinse filter with some 0.2 um filtered seawater

Place filters in scint vials and add 0.5 ml 0.5 N HCl to terminate reaction.

Incubate the light bottle and the dark bottle in a water filled dispail with ambient light under two layers of neutral density screening with a flowing seawater pump.

Incubate the bottles for three hours and then sample 2 x 100 ml for dark and light bottles, as described for the T=0 samples.

Dissolve filters with 1 ml of ethyl acetate.

Add 10 ml of Ecoscint A and count.

Sample 2 x 100 ml of seawater into a light and a dark bottle.

Add 25 μl (50 μCi) of 14C using a Hamilton syringe to both.

Close lid and shake up well.

Immediately sample 25 ml from each bottle by filtering onto Millipore GS filters on the radio-dedicated polycarbonate 14C filtration manifold.

Rinse with 5 ml of 0.2 μm filtered SW using a wash bottle.

Incubate the bottles for two hours and then sample 2 x 25 ml for dark and light bottles. As described for the T=0 samples.

Filter and count filters as above

Dilute 14C by adding 10 μl (20 μCi) to 10 ml TE pH 8.0 and vortex.

Place a milipore GS filter in the bottom of three scint vials.

Add 1 ml of ethyl acetate to each and dissolve the filters.

Add 10 ml of Ecoscint A and 1 ml of 0.01 N NaOH to each and mix.

Add 5 μl diluted 14C (=22,200 DPM) to two vials. The third is the blank.

Count all three (efficiency = (CPMsample –CPMblank) / 22,200).