HLY-02-03 Primary Production (Excel) [Hill, V.]

Primary productivity was measured by 14C (carbon) uptake fixation with simulated in situ (SIS) incubations. Isotope stocks were prepared according to the recommendations of Fitzwater et al., 1982. Our SIS incubator had neutral density and/or blue plastic filters to simulate in situ irradiance spectra at depths consistent with sample collection. Temperature was regulated with flowing surface seawater. Samples were placed in 280ml polycarbonate bottles and inoculated with 370 kBq 14C-NaHCO3 and incubated for short period (S) 6-8 hours and long period (L) ~24 hours. Total activity added and particulate adsorption was measured at time zero in parallel samples. Particulate material was harvested on 25mm Whatman GF/F filters and rinsed with 5-10ml of 0.01 N HCL in filtered seawater to remove inorganic carbon. Radioactivity was assayed by liquid scintillation counting and corrected for particulate adsorption at time zero, background and counting efficiency. Dataset includes hourly (mg C m-3 h-1) and daily rates (mg C m-2 d-1) of 14C uptake measured with both short and long incubation periods with matching chlorophyll (mg m- 3) measuring using the fluorometric method of Holm-Hansen (1965) by Dean Stockwell of the University of Alaska, Fairbanks. An ASCII version of this dataset is available as a companion dataset. These Excel data were collected aboard the U.S. Coast Guard Cutter (USCGC) Healy cruise HLY-02-03.