Dataset: NAB08 C-14 PP

CTD data are reported as cast number and not as station number.

CTD Rosette system profiled at 0.5 m s-1 between the surface and 200 m, and at 1 m s-1 below 200 m.

Bottles were fired on the upcasts, 60 s after the CTD stopped. Sensor data are averages of a 30-s stationary period immediately before the bottle was fired.

Data Processing:

Fluorometric chlorophyll a (chl_a_fluor):
Water samples for fluorometric analysis of chlorophyll and pheopigments were filtered through Whatman GF/F filters. Triplicate water samples were collected at 10 m. Filters were extracted in 5 ml of 90% acetone at -20 C for 24 h and read on a Turner Designs Model 10-AU Digital fluorometer. The fluorometer was calibrated before and after the field program with Turner Designs chlorophyll standards. Chlorophyll was determined following JGOFS protocol procedures (Knap et al., 1996). For additional details on laboratory analysis of discrete water samples see Supplimental Document: Laboratory_analysis_report-NAB08.pdf.

C-14 primary productivity incubations (PP_C14 vs. PAR experiments):
Samples were collected a depth near to the Chl a maximum, as determined by in situ fluorometery. Each sample was subdivided into 14 50 ml transparent glass bottles and inoculated with known activity of H14CO3- ( i.e. ~ 2 µ Ci pr. bottle ). Subsamples were incubated in duplicate at 7 different PAR levels between 0-400 µmol m-2 s-1 in a temperature regulated incubator. Light was provided using a daylight simulating fluorescent tube panel and its intensity was adjusted using neutral, perforated metal screens. After 2 hours of incubation the content of each sub sample was filtered on Whatman GF/F glass fibre filter and the filter dried for storage until counting of the C-14 activity in a scintillation counter after finishing the series of cruises. Prior to counting of the activity, the filters were fumed in concentrated HCl in a desiccator for 5 minutes, and the scintillation readings were finally adjusted according to an established quenching correction curve for the sample treatment and instrument.