1)FILE NAME: 96MMFLL2.SMa 2)YEAR: 1996 3)PI: Mary Ann Moran 4)OTHERS: Wade Sheldon, Julie Amft 5)BRIEF DESCRIPTION OF DATA FILE: Calibrated DOM fluorescence data and apparent DOM change throughout the St. Mary's River, with salinity and other relevant data. 6)KEYWORDS: fluorescence,dom,cdom,humates,exchange,mixing,St. Mary's 7)RESEARCH LOCATION: Low water survey 2 from -2.02km to 27.27km on the St. Mary's River, performed during the LMER3 cruise aboard the R/V Bluefin (19-Jul-96). 8)EXPERIMENTAL DESIGNS AND METHODS: River water was pumped continuously from a depth of 1.5m, passed through a debubbling chamber, then fed through a series of flow-through instruments on board the R/V Bluefin. Salinity and temperature were measured by a Sea-Bird Electronics CT (SBE-3), turbidity was measured by a Turner Designs nephelometer, and DOM fluorescence measured by a Turner Designs model 10-AU-005 field fluorometer with near-UV bulb, narrow-pass 360nm excitation filter, and >450nm cut-off emission filter. A 50 micrometer cartridge filter was placed inline before the DOM fluorometer, which was the last instrument in the system. The fluorometer was standardized just prior to the survey; readings were zeroed to a solution of 0.1N H2SO4 in deionized water, and standardized with 0.1mg/L quinine bisulfate in 0.1N H2SO4 (set as 100 fluorescence units). Data from the CT, nephelometer, and DOM fluorometer were integrated with date, time, and GPS position data and logged at 15 sec intervals by the Bluefin's ODIS data acquisition system. Immediately following the survey, quantitative fluorescence dilution experiments were performed using water samples from the freshwater end-member of the estuary (collected on the same day). Fluorescence versus dilution curves were generated using both deionized water and aged Georgia continental shelf water as diluents. Data from these experiments were fit to a compound nonlinear model; parameters from this model were then used to calibrate the DOM fluorescence results to correct for errors due to quench and chromophoric DOM-seasalt interactions (Willey, 1984; Willey and Atkinson, 1982). Data were also corrected for time lags between CT and fluorescence measurements by examining time offsets following abrupt discontinuities in the data stream. 9)NOTES AND COMMENTS: Aberrant fluorescence values resulting from interruptions in water flow during filter changes were replaced with the value "ND". Data can be matched with CTD station locations using river distance or GPS coordinates. 10)VARIABLES DESCRIPTION: Variable Variable Description Precision/Units Coded DATE survey date MM-DD-YY n TIME time of measurement 0000 hrs-min n N_LAT North latitude 0.001 degree n W_LONG West longitude 0.001 degree n RIVDIST river distance 0.001 km n RD_FLAG river distance flags 0/1 flag/no flag n SALIN salinity 0.001 ppt n TEMP temperature 0.01 degree C n TURBID turbidity 0.001 nephles n DOMFL_O observed DOM fluorescence 0.001 quinine units n DOMFL_P predicted DOM fluorescence 0.001 quinine units n DOM_CHG cumulative DOM change 0.01 percent n 11)CALCULATIONS: RIVDIST and RD_FLAG are output parameters from LMERDIST, the GARLMER Project river distance calculation program for Matlab. Distances are calculated relative to beach-head, and are synchronized to nominal 2km CTD station positions. Flag values of 1 indicate GPS positions that are >0.5km from the LMERDIST reference transect, rendering distance calculations unreliable. Intermediate variables from fluorescence calibration models: Model 1 (deionized water dilution experiment): FL(di) = (a*DF)/(b+DF) where DF=(vol sample)/(vol sample+vol diH2O) NOTE: in the final model application, DF is calculated from salinity using the mixing equation: DF=(S(sem)-S)/(S(sem)-S(fem)), where S(sem) and S(fem) are salinities of the seawater and freshwater end-members, respectively. Model 2 (seawater dilution experiment): deltaFL(sw) = (FL(sw)-FL(di))/FL(di) = (A-D)/(1+(S/C)^B)+D where S=salinity DOMFL_P = p(FL(di)) * (1 + p(deltaFL(sw))) where 'p' denotes predicted values calculated using calibration model fits and measured salinity DOMFL_O = FL(raw)-(DOMFL_P-(a/b*DF)) where 'a' and 'b' are parameters from model 1 and FL(raw) is the uncorrected fluorescence DOM_CHG = ((DOMFL_0 - DOMFL_P) / DOMFL_P) * 100 12)FOR MORE INFORMATION, CONTACT: Wade Sheldon Dept. of Marine Sciences University of Georgia Athens, GA 30602 wade@wiegert.marsci.uga.edu 13)OTHER DATA FILES TO REFERENCE: 95MMFL??.SMb 96MMFL??.SMb 14)REFERENCE CITATIONS: Willey, J.D. and L.P. Atkinson. 1982. Natural fluorescence as a tracer for distinguishing between Piedmont and coastal plain river water in the nearshore waters of Georgia and North Carolina. Estuarine, Coastal and Shelf Science. 14:49-59. Willey, J.D. 1984. The effect of seawater magnesium on natural fluorescence during estuarine mixing, and implications for tracer applications. Marine Chemistry, 15:19-45. Sheldon, W.M., J.O. Blanton, J.E. Sheldon, R.E. Hodson and M.A. Moran. 1996. Calibration and interpretation of natural fluorescence data for use in DOM flux and estuarine mixing studies. Poster presented at the NSF LMER All-Scientists Meeting, Savannah, Georgia. 15)FORMAT OF VARIABLES: FILE NAME: 96MMFLL2.SMb Column No. Column Name Type Width Decimals 1 DATE DATE 8 2 TIME NUMERIC 4 0 3 N_LAT NUMERIC 7 4 4 W_LONG NUMERIC 7 4 5 RIVDIST NUMERIC 6 3 6 RD_FLAG NUMERIC 1 0 7 SALIN NUMERIC 6 3 8 TEMP NUMERIC 5 2 9 TURBID NUMERIC 5 3 10 DOMFL_O NUMERIC 7 3 11 DOMFL_P NUMERIC 7 3 12 DOM_CHG NUMERIC 5 2 16)NUMBER OF RECORDS: 811 17)STATUS: type 3 18)FOR ARCHIVAL USE: