ReadMe file: 
SBI: HLY-02-01 and HLY-02-03 data from Dr. Glenn Cota and Dr. Victoria Hill

TITLE: 	Primary Productivity data

AUTHORS:

Dr Glenn F. Cota
Center for Coastal Physical Oceanography
Old Dominion University
Norfolk VA 23529

Dr. Victoria J. Hill
Department of Ocean Earth and Atmospheric Science, ODU
4600 Elkhorn Ave
Norfolk VA 23529
757.683.4911 (tel)
757.683.5303 (fax)
email vhill@odu.edu


Data questions contact:  Dr V. J. Hill

 
FUNDING SOURCE AND GRANT NUMBER:  NSF – OPP – 0125049


DATA SET OVERVIEW: 

14C Primary Productivity data.

Data is from two cruises in the Chukchi and Beaufort Seas onboard the USCGC Healy 
WAGB-20 during the spring (HLY-02-01) and summer (HLY-02-03) of 2002 as part of 
the SBI phase II project.  A summary list of Bio-Optical stations and locations from the 
two cruises are given in file Stn_List_Arc2002.txt.  Detailed station information can be 
found in the individual station sheets.   Station sheets and photos are listed by year, 
month, day, and order for that day.

Time period covered by the data:
	Spring cruise (HLY-02-01) 		  8 May 2002 to 13 June 2002.
	Summer cruise (HLY-02-03) 	18 July 2002 to 21 August 2002. 

Physical location of the measurement 
See Stn_List_Arc2002.txt for summary list of station locations. 
Spring cruise (HLY-02-01) Arc2002-1
	Min Lat:  65deg 01.380min; Max Lat: 73deg 47.040min (North)
	Min Lon: -169deg 03.105min; Max Lon: -154deg 13.081min (West)
Summer cruise (HLY-02-03) Arc2002-2
	Min Lat:  67deg 30.262min; Max Lat: 73deg 40.439min (North)
	Min Lon: -168deg 54.675min; Max Lon: -151deg 46.506min (West)


INSTRUMENT DESCRIPTION:

Packard TRI-CARB 2300TR Liquid Scintillation Analyzer
      

DATA COLLECTION and PROCESSING: 
Carbon fixation was measured in surface waters (<90m) at selected stations between 7-
9am (local time), with additional chlorophyll taken in parallel. Discrete samples were 
collected in 30L Niskin bottles for chlorophyll and productivity measurements. Optical 
depths for productivity were estimated with the Secchi disk using Holmes (1970) and 
corresponded to 80-100, 50, 30, 15, 5 and 1% of surface irradiance. These depths are 
consistent with in situ irradiance measurements taken after the productivity cast using a 
Satlantic free-falling profiling 13 channel radiometer.

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.

Technical difficulties with the ship board seawater flow through system necessitated the 
use of a refrigerated van system to cool water and the forward ballast tanks to store 
water. These activities were outlined in the appendix to the cruise report which is 
available at www.joss.ucar.edu/sbi/. 


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.




DATA FORMAT:
Data is in SeaBASS format (ASCII) tab delimited with a SeaBASS header.  The headers 
include parameters, units, time, location, and other Meta data.

 
DATA REMARKS: 
Missing or questionable data was not included in the submitted data set or is noted in 
the header information of the file. Negative productivity rates occur when production is 
to low to be measured. The label -999 signifies missing data.


 
REFERENCES:

Fitzwater, S. E., Knauer, G. A.,Martin, J. H., 1982. Metal contamination and its effect on 
primary production measurements. Limnology and Oceanography. 27 (3), 544-551.
Holmes, R. W., 1970. The sechi disk in turbid coastal waters. Liminology and 
Oceanography. 15 (5), 688-694. 
Holm-Hansen, O., Lorenzen, C. J., Holmes, R. W., and Strickland, J. D. H. (1965), 
Fluorometric determination of chlorophyll, J.Cons.perm.int.Explor.Mer., 30 (1), 3-15.