US JGOFS Antarctic Environments Southern Ocean Process Study (AESOPS) Revelle Leg KIWI07, APFZ Process I, December 1997 - January 1998 Documentation for: THE TRACE METAL ROSETTE BOTTLE DATA L.A. Codispoti (lou@ccpo.odu.edu) Old Dominion University, November, 1998 General Comments: This "readme" file pertains to the salinity, and nutrient data taken from 30 liter Go-Flo sampling bottles on the trace metal rosette employed during the AESOPS Process I leg on board the R/V Roger Revelle (RR07). Dr. Richard T. Barber of the Duke University Marine Lab (rbarber@duke.edu) was the chief scientist during this leg. This cruise was the first process study leg on the R/V Roger Revelle during the U.S. JGOFS program in the Southern Ocean (AESOPS). The Revelle legs focused on the Polar Front region and complemented several AESOPS cruises on board the R/V Nathaniel Palmer which focused on the Ross Sea. THE TRACE METAL CLEAN ROSETTE ON THIS LEG WAS EQUIPPED WITH 6, 30-L GO-FLO BOTTLES AND DID NOT INCLUDE A CTD. IT WAS A TEMPERARY REPLACEMENT FOR THE 8-BOTTLE, CTD EQUIPPED SYSTEM THAT WAS LOST ON 13 NOVEMBER, 1997. Bottle data taken throughout the cruise with the hydrographic rosette equipped with 24, 10 liter Bullister bottles have been submitted to the U.S. JGOFS data base in a separate file. The trace metal and hydrographic rosette data are in different files because of the absence of a CTD on the trace metal rosette and because Go-Flo bottles while superior for obtaining "trace metal clean" samples are not as likely to produce as high quality hydrographic data as the Bullister bottles. Some questionable data are not included in this report. These data are available upon request. No units are given for salinity in this report because the most recent definitions of salinity define it as a dimensionless number. To accommodate every preference, Winkler oxygen values are reported in ml/l, micromolar and micromoles per kg. The latter values can only be calculated with a knowledge of the oxygen sample temperatures when the samples were drawn. These "draw temperatures" are not reported here, but can be obtained by contacting lou@ccpo.odu.edu. Nutrient values are reported in micromolar. They can be converted to micromoles per kg, by combining a temperature of 23 deg. C and the salinity of the sample to compute density and then dividing the value in micromolar by this number. The recommended temperature takes into account conditions on this cruise vis a vis laboratory temperature, standard preparation, and sample temperatures. Methods: In general, the methods employed for the bottle salinity, and nutrient analyses did not differ significantly from those described in the JGOFS protocols that were distributed in 1994 (UNESCO, IOC Manual and Guide #29). Minor differences included the following: 1) The protocols give one a choice of adjusting nutrient methods so that calibration curves are strictly linear, or opting for more response and taking into account non-linearities. We choose the latter method. 2) No corrections were made for "carryover" between nutrient samples run on the Technicon Autoanalyzer. Carryover effects in our nutrient analyses are generally less than ~2% of the concentration difference between adjacent samples, and were minimized by arranging samples in depth order, etc. 3) Calibration and re-calibration of volumetric ware were not exactly as described in the JGOFS protocols, but all volumetric flasks, maxipettors, and dosimats were calibrated. 4)Duplicate oxygen samples were not routinely drawn. 5) The JGOFS protocols do not describe an automated technique for the analysis of ammonium concentrations. We employed the Berthelot reaction using a method somewhat similar to the method described by Whitledge et al. (1981, Whitledge, T.E., Malloy, S.C., Patton, C.J. and Wirick, C.D. Automated Nutrient Analyses in Seawater. Brookhaven National Laboratory Rept. BNL 51398, 216pp.). Depth/Pressure Due to the absence of a CTD system on this rosette, depths are based on meter wheel readings. Temperature: Due to the absence of a CTD system on this rosette, no temperature data are available, but consulting the companion data collected with the hydrographic rosette should give the user a reasonable idea of the in situ temperatures associated with each sample. Sampling: The samples in this report were taken from ~30 liter Go-Flo bottles. Because there is little or no lag time between triggering a bottle and bottle closure, our sampling protocols request that bottles be held at the sampling depth for at least 30 seconds before tripping. Salinity: Bottle salinities were determined with Guildline Autosal salinometers. New vials of standard sea-water were used to standardize before and at the end of every run. Dissolved oxygen: The Winkler dissolved oxygen apparatus was built and supplied by the Scripps Institution of Oceanography (SIO)'s Ocean Data Facility (ODF) group. This system is computer controlled and detects the end-point photometrically. Temperatures of the thiosulfate and standard solutions are automatically monitored by this system. Nutrients: Note that the terminology used to describe nutrients has become somewhat loose over the years and that silicate = silicic acid, dissolved silicon or reactive silicate, and phosphate = reactive phosphorus. Nutrient analyses were performed on a 5-channel Technicon II AA system that was modified and provided by Doug Masten (doug@odf.ucsd.edu) of the ODF group at the Scripps Institution of Oceanography. Queries: Questions about these data may be addressed to: Dr. L. A. Codispoti CCPO Old Dominion University Norfolk, VA 23529 lou@ccpo.odu.edu