US JGOFS Antarctic Environments Southern Ocean Process Study (AESOPS) Revelle Leg KIWI08, APFZ Survey 2, 8 Jan. - 8 Feb. 1998 Documentation for: The Trace Metal Rosette Hydrographic bottle data L.A. Codispoti (lou@ccpo.odu.edu) Old Dominion University, December, 1998 General Comments: This "readme" file pertains to the salinity, dissolved oxygen, and nutrient data taken from sampling bottles with the trace metal rosette that was equipped with 8 ~30-liter teflon coated "Go-Flo" bottles made mostly of PVC and equipped with orange silicone o-rings during Revelle leg RR08 (8 January - 8 February 1998). This rosette system was equipped with a Sea-Bird SBE-19 CTD. Dr. Kenneth H. Coale of the MossLanding Marine Laboratories (coale@mlml.calstate.edu) was the chief scientist during this leg. This cruise was the second survey 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 that focused on the Ross Sea. Several casts with a hydrographic rosette equipped with 24, 10-l Bullister bottles and a higher resolution CTD system were also taken during this leg. These hydrographic data are of "WOCE" quality and have been submitted as a separate file because of the different capabilities of the two CTD/rosette systems. Additional hydrographic data were collected by other research teams, and will be submitted to the data base by these groups. These additional observations included observations from towed undulating devices and from trace metal clean bottle casts made by hanging bottles on Kevlar cable. Investigators interested in these data can find out about their status by consulting the chief scientist. The user should also be aware that considerable underway hydrographic data were also collected during this leg and these data are not included in this report. Some questionable data are not included in this report. These data are available upon request. ---------------------------------------------------------------- IN PARTICULAR, PLEASE NOTE THAT PROBLEMS WERE ENCOUNTERED WITH THE AMMONIUM ANALYSIS AT THE BEGINNING OF THIS CRUISE. THUS, AMMONIUM DATA ARE NOT REPORTED UNTIL STATION 4, CAST 2 IN THIS REPORT AND UNTIL STATION 4, CAST 3 IN THE COMPANION HYDROGRAPHIC ROSETTE DATA REPORT THAT HAS BEEN SUBMITTED TO THE JGOFS DATA BASE. ---------------------------------------------------------------- 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. For the laboratory conditions on this leg, the nutrient values in micromolar can be converted to micromoles per kg, by combining a temperature of 21 deg. C and the salinity of the sample to compute density and then dividing the value in micromolar by this number. Methods: In general, the methods employed for the bottle salinity, Winkler dissolved oxygen, 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. in some cases. 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.). Temperature: The temperature data associated with each bottle depth were taken by the CTD system during the bottle tripping process. Consult the companion CTD data report for this cruise to learn more about the CTD system. 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 with the new Sea-Bird rosette systems, our sampling protocols request that bottles be held at the sampling depth for at least 30 seconds before tripping. NOTE THAT THE MID-POINTS OF THE SAMPLING BOTTLES WERE ~ O.5 METER ABOVE THE CTD SENSORS. THE DATA HAVE NOT BEEN CORRECTED FOR THIS OFFSET. Salinity: 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. Agreement between bottle salinities and the recently calibrated sensors on the Sea-Bird SBE-19 CTD was usually better than 0.02 before post-cruise data processing which employs the bottle salinities to correct the CTD salinities. Some larger differences occurred in gradients because of the response time characteristics of the sensors in this system which did not produce high quality data in gradients during the cruise. More information on the quality of thesalinity data are given in the companion CTD report. Dissolved oxygen: The Winkler dissolved oxygen apparatus was built and supplied by the Scripps Institution of Oceanography's (SIO) 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. ALSO READ THE NOTE REGARDING PROBLEMS WITH THE INITIAL AMMONIUM RESULTS IN THE "GENERAL COMMENTS" SECTION ABOVE. Queries: Questions about these data may be addressed to: Dr. L. A. Codispoti CCPO Old Dominion University Norfolk, VA 23529 lou@ccpo.odu.edu