(1) FILE NAME:  97MMDOCL.ALa
     DATA FILE NAME:  97MMDOCL.ALb

 (2) YEAR:  1997

 (3) PI:  Mary Ann Moran

 (4) OTHERS:  Wade Sheldon, Joe Covert

 (5) DESCRIPTION OF DATA FILE:  Dissolved organic carbon concentrations 
     at various locations in the Altamaha during LMER 5 low tide surveys.

 (6) KEYWORDS:  Altamaha, dissolved organic carbon, humic acid fraction, 
     non-humic acid fraction, doc, absorbance, absorption coefficient

 (7) RESEARCH LOCATION:  Various locations in the south and north channels
     of the Altamaha River and adjacent portions of the Intracoastal Waterway.

 (8) EXPERIMENTAL DESIGN AND METHODS:  River water was collected in 2L
     HCl-washed polyethylene bottles from a depth of 0.5-1m after rinsing
     3 times with sample water.  Salinity and temperature were measured 
     using an Orion 140 Conductivity/Salinity meter with solid-state probe;
     the Orion meter was cross-calibrated with the Bluefin's SBE-21 CT using
     a wide range of salinity samples. Duplicate 20ml subsamples were filtered 
     through ashed Whatman GF/F filters in ashed glass filtration units and
     stored at 4 degrees C until processing.  Immediately before analysis,
     samples were acidified to pH 3 with 10% phosphoric acid and bubbled with
     CO2-free air for 15 minutes.  Samples were then injected into a Shimadzu
     TOC 5000 carbon analyzer standardized with potassium biphthalate.  The
     absorbance of each sample at 350nm wavelength was also measured with a
     Beckman DU-640 spectrophotometer using a 5cm quartz cell and deuterium
     UV lamp.

 (9) NOTES AND COMMENTS:  Missing values are replaced with NaN.

(10) DESCRIPTION OF VARIABLES:

     Variable       Variable Description                      Precision/Units    Coded
     --------       --------------------                      ---------------    -----
     DATE           date                                      mm-dd-yyyy         N
     TIME           24 hr GMT                                 hh:mm:ss           N
     LAT_DEG        latitude degrees                          deg N              N
     LAT_MIN        latitude minutes                          min N              N
     LONG_DEG       longitude degrees                         deg W              N
     LONG_MIN       longitude minutes                         min W              N
     RIVER          river/waterway name                       2 chars            N
     STATION        distance upriver                          0.001 km           N
     SALINITY       salinity                                  0.001 PSU          N
     DOC            DOC concentration (mean)                  0.01 mg/L          N
     DOC_SD         standard deviation of DOC measurement     0.001 mg/L         N
     DOC_LCL        95% lower confidence limit of DOC         0.01 mg/L          N
     DOC_UCL        95% upper confidence limit of DOC         0.01 mg/L          N
     ABS_COEFF      absorption coefficient (350nm)            0.01 1/m           N
     S_ABS_COEFF    specific absorption coefficient (350nm)   0.01 mg/L/m        N


(11) CALCULATIONS:

     RIVER and STATION are output parameters from LMERmap, the GARLMER Project
        mapping and river distance calculation program for Matlab.

        Note:  Station distances are calculated relative to the line of
        demarcation, and are synchronized to nominal 2km CTD station positions.
        Distance values designated NaN (not a number) indicate locations greater
        than 3km from the main channel of any GARLMER study river (i.e. defined
        as outside the confines of the river)

     DOC and DOC_SD were computed for 5 injections per sample by the Shimadzu
        TOC-5000 control and analysis software.

     DOC_LCL and DOC_UCL were calculated as:

        DOC_LCL = DOC - T(alpha/2,df=N-1) * DOC_SD/(N^0.5)

        DOC_UCL = DOC + T(alpha/2,df=N-1) * DOC_SD/(N^0.5)

        where:  N = number of injections, alpha = .05

     ABS_COEFF = 2.303 * Absorbance(350nm) / pathlength(m)

     S_ABS_COEFF = ABS_COEFF / DOC

(12) FOR MORE INFORMATION, CONTACT:  

     Wade Sheldon
     Dept. of Marine Sciences
     University of Georgia
     Athens, GA 30602-3636
     wade@wiegert.marsci.uga.edu

(13) OTHER DATA FILES TO REFERENCE:

     97MMODS?.ALb
     97MMDOCL.SLb

(14) REFERENCE CITATIONS:  None

(15) FORMAT OF VARIABLES:
     
     FILE NAME:  97MMDOCL.ALb

     Column #   Variable          Type       Width   Digits
     --------   ------------      -------    -----   ------
     1          DATE              date       10
     2          TIME              time       8
     3          LAT_DEG           numeric    2       0
     4          LAT_MIN           numeric    5       2
     5          LONG_DEG          numeric    2       0
     6          LONG_MIN          numeric    5       2
     7          RIVER             text       2
     8          STATION           numeric    7       3
     9          SALINITY          numeric    6       3
     10         DOC               numeric    5       2
     11         DOC_SD            numeric    4       2
     12         DOC_LCL           numeric    5       2
     13         DOC_UCL           numeric    5       2
     14         ABS_COEFF         numeric    5       2
     15         S_ABS_COEFF       numeric    4       2

(16) NUMBER OF RECORDS:  56

(17) STATUS: 3

(18) FOR ARCHIVAL USE
     Data File Validated By:  Wade Sheldon
     Date:  June 1998
     Date Received By Data Management:  23 June 1998
     Date Entered To Database:  5 August 1998
     Log Of Changes And Comments:
        1. August 1998 - minor editorial changes - tdb