LIMNO_CHEMISTRY English utf8 dataset McMurdo Dry Valleys LTER Information Manager im@mcmlter.org pointOfContact 2014-11-04 ISO 19115-2 Geographic Information - North American Profile Metadata - Data with Biological Extensions ISO 19115-2:2009(E) Ion concentrations in discrete water column samples collected from lakes in the McMurdo Dry Valleys, Antarctica (1991-2019, ongoing) 2014-11-04 publication John Priscu Montana State University http://www.montana.edu/ jpriscu@montana.edu pointOfContact Kathleen Welch University of Colorado Boulder http://www.colorado.edu/ kathleen.welch@colorado.edu pointOfContact W. Berry Lyons The Ohio State University https://www.osu.edu/ (614) 688-3241 275 Mendenhall Lab Columbus OH 43210 US lyons.142@osu.edu http://research.bpcrc.osu.edu/EnvironmentalGeochemistry/ pointOfContact documentDigital As part of the Long Term Ecological Research (LTER) project in the McMurdo Dry Valleys of Antarctica, a systematic aqueous geochemical sampling program has been undertaken. A series of terrestrial water samples have been collected and analyzed for major ion chemistry by ion chromatography. The concentrations of ions cover a wide range of total dissolved solids from fresh to hypersaline lake waters. This dataset shows concentrations of lithium, sodium, potassium, magnesium, calcium, chloride, bromide, silicon, fluoride, SO4, found in various depths of Taylor Valley lakes. Name: Renée F. Brown Role: data manager Name: Amy Chiuchiolo Role: former field crew Name: Inigo San Gil Role: former data manager completed McMurdo Dry Valleys LTER Information Manager im@mcmlter.org pointOfContact unknown Recent Changes On 2014, Inigo San Gil migrated the metadata into the Drupal Ecological Information System to modernize and improve the McMurdo Dry Valleys LTER services. Older Changes As part of a major database clean-up effort, Kathy Welch and Chris Gardner (database manager) decided to remake this entire table in July of 2007. It was found that there were numerous errors in the old table, including numbers in the wrong columns and errors with Si data. Kathy went through the data year-by-year and verified values against her original Excel files. The database table was remade with only mass values (mg/L) for each ion. The database then calculates molar values dynamically when the table is accessed. This table is now accurate a represents the most updated chemistry record for the dry valley lakes. The original iterations of the 'limnchem' file (limnological chemistry data) were created by Kathy Welch, and submitted to the Institute of Arctic and Alpine Research (INSTAAR) in a July 10, 1997 email message. Following discussions between Kathy Welch (who submitted data) and Denise Steigerwald (data manager), it was decided to remove some fields (eg., dilution factor, sample name), and add others (eg. collection site, collection date, comments for each type of measurement) to these files in order to make them more consistent and relational for future references. The resulting files contain the same name, but have 'xls' extensions. (They were altered using Microsoft Excel). Following these revisions, they were imported into Microsoft Access and saved in a table named "Limnological Chemistry 1991-95 (Welch / Lyons)" Because location name, collection date, and depth are all variables for this table, it was possible to combine each of these files in one table. This table was exported as an ascii, text, comma delimited file named "limnchem.dat" and saved in the appropriate directory to make it accessible on the web page. Data for 1998-2000 was submitted to the Data Manager (Kevin Wheeler) as files Limno_IC_9899.xls and Limno_IC_9900.xls. inorganic nutrients theme LTER Core Areas English ground condition 1991-11-21 2019-12-17 https://mcm.lternet.edu/sites/default/files/data/mcmlter-lake-chemistry-20220207.csv LIMNO_CHEMISTRY eng; US McMurdo Dry Valleys LTER LIMNO_CHEMISTRY Data Source Definition : Limno chemistry Record Delimiter : \n Number of Header Lines : 1 Number of Footer Lines : 1 Orientation : Column Quote Character : "Field Delimiter : , false DATASET_CODE Code to designate the table name LIMNO_RUN Code for lake's sampling location and date LOCATION NAME Name of lake where measurement was made LOCATION CODE Code for site where measurement was made DATE_TIME Date sample was collected Date Time Format: mm/dd/yyyy Depth (m) Distance below the piezometric water level from which sample was drawn Sample Comments General comments about the sample Li (mg/L) mass concentrations Li (mM) millimolar concentration Li COMMENTS Comments Na (mg/L) mass concentrations Na (mM) millimolar concentration Na COMMENTS Comments on the Sodium concentration measurement K (mg/L) mass concentrations K (mM) millimolar concentration K COMMENTS Comments on the potassium concentration measurement Mg (mg/L) mass concentrations Mg (mM) millimolar concentration Mg COMMENTS Comments on the Magnessium concentration measurement Ca (mg/L) mass concentrations Ca (mM) millimolar concentration Ca COMMENTS Comments on the Calcium concentration measurements F (mg/L) mass concentrations F (mM) millimolar concentration F COMMENTS Comments on the concentration of Iron measurement Cl (mg/L) mass concentrations Cl (mM) millimolar concentration Cl COMMENTS Comments on the Chlorine concentration measurements Br (mg/L) mass concentrations Br (mM) millimolar concentration Br COMMENTS Comments on the concentration of Bromide measurement SO4 (mg/L) mass concentrations SO4 (mM) millimolar concentration SO4 COMMENTS Comments Si (mg/L) mass concentrations Si (mM) millimolar concentration Si COMMENTS Comments File Name Original file name before entered into database DEPTH MASL Depth referred to the Sea level. Distance below Mean Average Sea water level reference from which sample was drawn DBF https://mcm.lternet.edu/sites/default/files/data/mcmlter-lake-chemistry-20220207.csv dataset Quality Control: About Molar Units The Limnology chemistry table only contains mass units (mg/L) - molar units are calculated on the fly by the Oracle database. Therefore the number of significant figures may not be accurate. Please see the mass units for the appropriate number of significant figures  Lake sampling was carried out by lowering a Niskin bottle through a hole in the ice cover of the lake to specified depths. Samples were then collected in precleaned plastic bottles. Separate aliquots were collected in serum vials for pH and dissolved inorganic carbon (DIC) measurements. Samples were returned to field laboratories for processing and for time-sensitive analyses such as pH.                  Dedicated  sampling equipment for each lake has been important for maintaining the integrity of  the samples. For example, the range of Cl- concentration in the investigated lakes varies by more than three orders of magnitude. This carryover between samples becomes a potential problem. Carryover can also be a potential problem during analysis, and therefore analytical blanks are run to monitor this.                  The initial sample processing was  carried out in field laboratories. A 100-ml sample aliquot was filtered for each anion and cation sample. All samples were filtered through 0.4-microm Nucleopore filters,  usually within 12h of collection. The cation samples were filtered into acid-washed polyethylene bottles which had been rinsed with DI water, while the anion samples were  filtered into DI-washed bottles. The cation samples were acidified by adding 0.5%  (v/v) of concentrated HCl. Quality control was maintained by carefully rinsing all filtration apparatus with DI between samples and by processing filtration blanks which  were later run as samples.                  The majority of water chemistry samples were returned to the Crary Laboratory, McMurdo Station, Antarctica, for analysis. Some of the samples  were returned to the laboratory at the University of Alabama  (pre 2000) or the Ohio State University (post 2000) for analysis owing to  time constraints during the field season.                    DX-300 ion chromatographic system was used for the major ion analyses. The system included a gradient pump module, high-pressure injection valve with a 25-microm sample loop, a Dionex conductivity detector (CDM-3)  advanced computer interface and automated sampler. The timed events and data collection were controlled by the Dionex AI-450 chromatography software for Windows.  The same ion chromatographic system was used but was switched back and forth between anion and cation configurations.                 Appropriate dilutions of the stock standards were used to prepare a range of standards for calibration. Owing to the high salt concentrations in many of the samples, dilutions were made before the samples were run. Dilutions ranged from 1:2 for Lake  Hoare surface water up to 1:6000 for the Lake Bonney deep water. The samples were diluted by serial dilution, using plastic microbeakers and adjustable pipettors.                 Replicate and duplicate samples were run daily. Usually, each sample was injected twice and samples from each batch were run in duplicates to check the precision of the dilutions. In almost every case, the relative standard deviation of the duplicates was less than 1%, even with dilutions of 1:6000. In addition, analytical blanks and filtration blanks were analyzed to check the quality control.                Dissolved Silica analyses were done with the molybdate blue method.  After the 2007-2008 season silica analysis were done on a Skalar nutrient analyzer at the OSU                Lake water samples were analyzed in the field laboratories for DIC with an infrared gas analyzer. The DIC data was used with the other major ion data to calculate ionic balances as a further check on the data  Metadata Access Constraints: none Metadata Use Constraints: none annually McMurdo Dry Valleys LTER http://mcmlter.org/ pointOfContact