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, and dissolved inorganic carbon found in various depths of Taylor Valley lakes.
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.
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