| Data Tables, Images, and Other Entities: |
| Data Table: | Limno_Chemistry_Units
View Table Metadata |
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Short Name: | limnochem |
| Online Distribution Info: |
| Download File: |
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| Data Set Owner(s): |
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Individual: | W. Berry Lyons |
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Address: |
| Byrd Polar Research Center, |
| Ohio State University, |
| 108 Scott Hall, |
| 1090 Carmack Rd, |
| Columbus, OH 43210-1002 USA |
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Individual: | Kathleen Welch |
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Address: |
| Byrd Polar Research Center, |
| Ohio State University, |
| 108 Scott Hall, |
| 1090 Carmack Rd, |
| Columbus, OH 43210-1002 USA |
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| Metadata Provider(s): |
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Organization: | McMurdo Dry Valleys LTER |
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Address: |
| Byrd Polar Research Center , |
| 108 Scott Hall, |
| 1090 Carmack Rd, |
| Columbus, OH 43210-1002 USA |
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| Abstract: |
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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.
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| Keywords: |
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- lake
(theme)
- limnology
(theme)
- solute concentrations
(theme)
- inorganic
(theme)
- anions
(theme)
- cations
(theme)
- chemistry
(theme)
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| Additional Information: |
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| 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.
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| Notes |
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
corrected or qualified. Thus, these data may be modified and future data will be
appended.
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| License and Usage Rights: |
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| MCM LTER data may be used freely with the following restrictions: |
The Principal Investigator be sent a notice stating reasons for
acquiring any data and a description of the publication intentions.
The Principal Investigator of the data set be sent a copy of the
report or manuscript prior to submission and be adequately cited in any resultant
publications.
A copy of any resultant publications should be sent to the McMurdo
data manager and principal investigator.
The end-user follow the guidelines set forth in the LTER Network Data
Access Policy, Data Access Requirements, and General Data Use Agreement found at
http://www.mcmlter.org/data_guidelines.htm
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| Geographic Coverage: |
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Geographic Description: | Study areas were located in the McMurdo Dry Valley of southern
Victoria Land, Antarctica (in the western coast of the Ross Sea at 77 degrees 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.
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Bounding Coordinates:
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| West: | 162 degrees
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| East: | 163.6 degrees
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| North: | -77.2 degrees
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| South: | -77.8 degrees
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Mimimum Altitude: | 0 meter |
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Maximum Altitude: | 1000 meter |
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| Temporal Coverage: |
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Begin:
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End:
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| Maintenance: |
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Description:
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| Old changes to database |
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. All original
files are archived in /data1/data/lakes/lakechem directory.
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| Recent changes to database |
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
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Frequency:
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| Contact: |
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Organization: | McMurdo Dry Valleys LTER |
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Position: | Data Manager |
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Address: |
| Byrd Polar Research Center , |
| 108 Scott Hall, |
| 1090 Carmack Rd, |
| Columbus, OH 43210-1002 USA |
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Phone:
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Email Address:
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| Publisher: |
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Organization: | McMurdo Dry Valleys LTER |
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Address: |
| Byrd Polar Research Center , |
| 108 Scott Hall, |
| 1090 Carmack Rd, |
| Columbus, |
| Columbus, OH 43210-1002 USA |
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Phone:
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| Methods Info: |
| Step 1: |
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Description:
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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
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