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PRINCIPAL INVESTIGATOR: OTHERS: KEYWORDS: lake, limnology, solute concentrations, inorganic, anions, cations, chemistry
ABSTRACT: 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, iron, chlorine,
bromine, silicon, fluorine, SO4, and dissolved inorganic carbon found in various depths of Taylor Valley
lakes.
VARIABLES: limno run, location name, location code, date, depth (m), Li (mg/L), Li
(mM), Li comments, Na (mg/L), Na (mM), Na comments, K (mg/L), K (mM), K comments, Mg (mg/L), Mg (mM), Mg
comments, Ca (mg/L), Ca (mM), Ca comments, F (mg/L), F (mM), F comments, Cl (mg/L), Cl (mM), Cl comments, Br
(mg/L), Br (mM), Br comments, Si (mg/L), Si (mM), Si comments, SO4 (mg/L), SO4 (mM), SO4 comments, Fe (mg/L),
Fe comments, DIC (mg C/L), DIC (mM C/L), DIC comments, file name
RESEARCH LOCATION: Study areas were located in the McMurdo Dry Valley of southern Victoria Land,
Antarctica (in the western coast of the Ross Sea at 77°S). Specific sites include the eastern portion of Lake
Bonney, the western portion of Lake Bonney, Lake Fryxell, Lake Hoare, Lake Joyce, Lake Miers, Lake Garwood,
and Lake Vanda. Samples and original data are stored in the Department of Geology, University of Alabama,
Tuscaloosa, AL, Bevill Building, Room 213.
METHODS: 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-µm 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 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-µm 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.
For the anions, a Dionex Ionpac AS4A-SC analytical column (250x4mm I.D.) and AG4A-SC guard column (50x4mm
I.D.) were used along with an Anion Self-Regenerating Suppressor-1. The eluent was 1.8 mM Na2CO3-1.7 mM
NaHCO3. The gradient pump flow-rate was 2 ml/min and the background conductivity was ca. 16 µS.
For the cations, the Dionex Ionpac CS12 analytical column (250x4mm I.D.) and CG12 guard column (50x4mm I.D)
were used with a Cation Self-Regenerating Suppressor-1. The eluent was 0.020 M methanesulfonic acid. The
eluent flow-rate was 1.0 ml/min and the background conductivity was ca. 200-250 nS.
The stock standard solutions used for a typical batch of samples from the lakes are specified below:
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.
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
quality. Results of the ionic balance calcultaions are summarized below:
TIMING: Samples were collected from the following sites and dates: CITATIONS: Welch, K.A., Lyons, W.B, Graham, E., Neumann, K., Thomas, J.M., and D. Mikesell.
1996. Determination of major element chemistry in terrestrial waters from Antarctica by ion chromatography.
Journal of Chromatography A 739, 257-263.
COMMENTS:
STATUS: Public Access (Type 1).
VARIABLE DESCRIPTION: LOG: 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. These files are currently located in the /data1/data/lakes/lakechem directory
and contain the following names:
NOTE: Data contained in these files has been subjected to quality
control standards imposed by the investigator. The user of this data
should be aware that, while efforts have been taken to ensure that these
data are of the highest quality, there is no guarantee of perfection
for the data contained herein and the possibility of errors exists. If
you encounter questionable data, please contact the MCM LTER data manager
(; (303)492-4639) so that the data can be
corrected or qualified. Thus, these data may be modified and future
data will be appended.
CATION CONCENTRATION (mg/L) ANION CONCENTRATION (mg/L)
Na+ 100 Cl- 100
K+ 20 SO4(2-) 100
Mg(2+) 50 F- 10
Ca(2+) 50 Br- 2
Li+ 1
DIFFERENCES BETWEEN TOTAL ANIONS AND TOTAL CATIONS (%), WITH STANDARD DEVIATIONS IN PARENTHESES:
Lake Hoare 2.1 (2.1)
Lake Fryxell 3.0 (2.0)
East Lake Bonney 1.8 (1.4)
West Lake Bonney 1.4 (1.0)
Season East Bonney West Bonney Hoare Fryxell
91-92 21-Nov-91
25-Dec-91
22-Jan-92
93-94 27-Oct-93 29-Oct-93 5-Nov-93 16-Nov-93
24-Nov-93 26-Nov-93 1-Dec-93 7-Dec-93
21-Dec-93 23-Dec-93 30-Dec-93 7-Jan-94
19-Jan-94 18-Jan-94
94-95 2-Nov-94 5-Nov-94 10-Nov-94 14-Nov-94
23-Nov-94 25-Nov-94 30-Nov-94 4-Dec-94
17-Dec-94 19-Dec-94 24-Dec-94 30-Dec-94
10-Jan-95 12-Jan-95 20-Jan-95 17-Jan-95
95-96 19-Sep-95 21-Sep-95 7-Sep-95 14-Sep-95
6-Oct-95 4-Oct-95 25-Sep-95 28-Sep-95
17-Oct-95 19-Oct-95 10-Oct-95 14-Oct-95
2-Dec-95 5-Dec-95 21-Nov-95 26-Nov-95
1-Jan-96 4-Jan-96 23-Dec-95 27-Dec-95
96-97 3-Nov-96 1-Nov-96 8-Nov-96 26-Oct-96
24-Nov-96 27-Nov-96 2-Dec-96 19-Nov-96
15-Jan-97 17-Jan-97 12-Jan-97 9-Jan-97
97-98 8-Nov-97 11-Nov-97 15-Nov-97 18-Nov-97
20-Dec-97 22-Dec-97 26-Dec-97 29-Dec-97
98-99 9-Nov-1998 11-Nov-1998 3-Nov-1998 28-Oct-1998
6-Dec-1998 9-Dec-1998 1-Dec-1998 23-Nov-1998
30-Dec-1998 1-Jan-1999 26-Dec-1998 20-Dec-1998
99-00 6-Nov-1999 11-Nov-1999 17-Nov-1999 30-Oct-1999
3-Dec-1999 5-Dec-1999 12-Dec-1999 27-Nov-1999
28-Dec-1999 30-Dec-1999 4-Jan-2000 23-Dec-1999
Season Joyce Miers Garwood Vanda Vida Chad Chad at Narrows
91-92
92-93 22-Jan-94 3-Jan-94
93-94 17-Jan-94 17-Jan-94
94-95 30-Nov-94 25-Jan-95 24-Jan-95 1-Dec-94
96-97 5-Dec-96 10-Dec-96
97-98 9-Dec-97 5-Dec-97
Season Don Juan Pond Dirty Little Pony Lake on Skua Pond on Trough
Hoare Pond Ross Island Ross Island
93-94 1-Jan-94 27-Jan-94 27-Jan-94
95-96 8-Jan-96
96-97 22-Jan-97
98-99 23-Dec-98
VARIABLE TYPE DESCRIPTION UNITS MISSING VALUE INDICATOR MINIMUM MAXIMUM PRECISION
Limno run Text ID# associated with location, None Required entry n/a n/a n/a
collection date
Location name Text Lake where data was gathered None Required entry n/a n/a n/a
Location code Text Abbreviation used for that None Required entry n/a n/a n/a
location
Date Date Date sample was collected mm/dd/yy Required entry n/a n/a n/a
Li (mg/L) Number Lithium concentration milligrams/liter Null 0 50 0.0001
Li (mM) Number Lithium concentration millimoles/liter Null 0 5 0.0001
Li comments Text Comments pertaining to None Null n/a n/a n/a
lithium measurement
Na (mg/L) Number Sodium concentration milligrams/liter Null 0 100,000 1
Na (mM) Number Sodium concentration millimoles/liter Null 0 5,000 0.01
Na comments Text Comments pertaining to None Null n/a n/a n/a
sodium measurement
K (mg/L) Number Potassium concentration milligrams/liter Null
K (mM) Number Potassium concentration millimoles/liter Null
K comments Text Comments pertaining to None Null n/a n/a n/a
potassium measurement
Mg (mg/L) Number Magnesium concentration milligrams/liter Null
Mg (mM) Number Magnesium concentration millimoles/liter Null
Mg comments Text Comments pertaining to None Null n/a n/a n/a
magnesium measurement
Ca (mg/L) Number Calcium concentration milligrams/liter Null
Ca (mM) Number Calcium concentration millimoles/liter Null
Ca comments Text Comments pertaining to None Null n/a n/a n/a
calcium measurement
F (mg/L) Number Fluorine concentration milligrams/liter Null
F (mM) Number Fluorine concentration millimoles/liter Null
F comments Text Comments pertaining to None Null n/a n/a n/a
fluorine measurement
Cl (mg/L) Number Chlorine concentration milligrams/liter Null
Cl (mM) Number Chlorine concentration millimoles/liter Null
Cl comments Text Comments pertaining to None Null n/a n/a n/a
chlorine measurement
Br (mg/L) Number Bromine concentration milligrams/liter Null
Br (mM) Number Bromine concentration millimoles/liter Null
Br comments Text Comments pertaining to None Null n/a n/a n/a
bromine measurement
Si (mg/L) Number Silicon concentration milligrams/liter Null
Si (mM) Number Silicon concentration millimoles/liter Null
Si comments Text Comments pertaining to None Null n/a n/a n/a
silicon measurement
SO4 (mg/L) Number SO4 concentration milligrams/liter Null
SO4 (mM) Number SO4 concentration millimoles/liter Null
SO4 comments Text Comments pertaining to None Null n/a n/a n/a
SO4 measurement
Fe (mg/L) Number Iron concentration milligrams/liter Null
Fe comments Text Comments pertaining to None Null n/a n/a n/a
iron measurement
DIC (mg C/L) Number Dissolved inorganic milligrams of carbon Null
carbon concentration per liter
DIC (mM C/L) Number Dissolved inorganic millimoles of carbon Null
carbon concentration per liter
DIC comments Text Comments pertaining to None Null n/a n/a n/a
dissolved inorganic
carbon measurement
File name Text Raw data file containing None Null n/a n/a n/a
information
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. All original files are archived in /data1/data/lakes/lakechem directory.