| Data Tables, Images, and Other Entities: |
| Data Table: | Units_And_Column_Descriptions
View Table Metadata |
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Short Name: | limnchla |
| Online Distribution Info: |
| Download File: |
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| Data Set Owner(s): |
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Individual: | John Priscu |
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Address: |
| Department of Biology, |
| 309 Lewis Hall, |
| Montana State University , |
| Bozeman, MT 59717 USA |
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Phone:
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Email Address:
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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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Phone:
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Phone:
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Email Address:
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| Abstract: |
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An important part of the McMurdo Long Term Ecological Research (LTER) project
is monitoring of spatial and temporal patterns, and processes that control primary production
in perennial ice-covered lakes. This data set addresses this core area of research and
quantifies chlorophyll-a concentrations at specific depths in McMurdo Dry Valley
lakes.
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| Keywords: |
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- lake
(theme)
- limnology
(theme)
- primary production
(theme)
- chlorophyll-a
(theme)
- Antarctica
(theme)
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| Additional Information: |
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| Citations |
Holm-Hansen, O., C. J. Lorenzen, R. W. Holmes, and J. D. H. Strickland. 1965. Fluorometric determination of chlorophyll. J. Cons. Int. Explor. Mer. 30: 3-15.
Strickland, J.D.H. and Parsons. 1977. A practical handbook of seawater analysis. pg. 194.
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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: | Samples were collected from the East Lake Bonney, West Lake Bonney, Lake
Hoare, Lake Fryxell, Lake Joyce, and Lake Miers limnological sampling stations, located in the
McMurdo Dry Valleys of Antarctica. |
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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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Data from this table was submitted to INSTAAR by John Priscu's team at Montana
State University. The raw data files listed under 'file name' are the names of the original
files submitted. The 1993/94 and 1994/95 datasets are Microsoft Excel version 6.0 files, and
the 1995/96, 1996/97 and 1997/98 datasets are ascii text files. Upon arrival at INSTAAR, the
data manager fine-tuned the location codes and limno runs to match those provided in the
"locations, dates, codes for lake chemistry, biology samples" file. The file was imported
into Microsoft Access on INSTAAR's Unix system, and can currently be found there. The file
was then exported in ascii, comma delimited text and MS-DOS text (table layout) on the MCM
LTER web site. Both of these files are linked to this web page above. Information for the
metadata was obtained from the Metachl9697.rtf file. The file was called up using Microsoft
Word version 6.0. Text from this file was used to create this page in html
format.
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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 water samples were collected at specific depths with a five-liter Niskin bottle during normal
LTER limnological sampling. Sub-samples were decanted into three-1 L Nalgene bottles (2-light and 1-amber),
two-500 mL amber Nalgene bottles, three-150 mL borosilicate glass bottles, two-20 mL scintillation vials, and one-30
mL serum vial. Two-100 mL sub-samples were taken from the one-liter amber Nalgene bottle. In a darkened
environment, each sample was filtered through a combusted (475C for 4 hours) Whatman 25 mm GF/F using a
bell jar apparatus. The filter was folded in half (organic material inside), placed in a glassine envelope, covered
with aluminum foil, and frozen immediately for later analysis in McMurdo. The filtrate was collected for nutrient
and dissolved organic carbon analyses.
In McMurdo, chlorophyll-a standards were prepared by dissolving 1 mg of chlorophyll-a in a 100 ml volumetric
flask and diluting it to mark with a 1:1 solution of 90% acetone and DMSO. A Beckman DU-640 UV/vis spectrophotometer
was used to determine the actual stock concentration. The absorbance of the stock solution was determined at l=665 nm
and l=750 nm; The corrected initial absorbance was calculated (665o = Abs.665 - Abs.750). The stock solution was acidified
in the cuvette using 4 drops of 3 N HCl and analyzed again. The absorbance after acidification was used at l=665 nm and
l=750 nm to determine 665a (665a = Abs.665 - Abs.750). Chlorophyll-a content was determined by the following equation:
Chl-a = 26.7 x (665o - 665a) x v
V * L
where v = extract volume, V = volume of water filtered, and L is the pathlength of the cuvette. The stock solution was used to
prepare six standard solutions of chlorophyll-a ranging from ~ 0.0015 ug ml-1 to 0.150 ug ml-1. Fo and Fa were obtained for
each standard by collecting initial fluorescence data, and then acidifying the standard in the cuvette with 4 drops of 3 N HCl.
The cuvette was briefly vortexed before determining Fa.
Each filter was placed into a 20 ml scintillation vial and extracted with 10 ml of 1:1 solution of 90% acetone and DMSO. The extract
was incubated for ~12 hours under cold (<0C), dark conditions. After incubation, 4 ml of extract was briefly vortexed &
dispensed into the cuvette; the cuvette was inserted into the Turner 10-AU fluorometer. After Fo was determined, the sample was
acidified with 4 drops of 3 N HCl, vortexed, and Fa was determined. The cuvette was rinsed three times with DI water and three
times with 90% acetone to ensure there was no cross contamination between samples. The cuvette exterior was wiped with
Kimwipes. The Fo-Fa was determined for each sample and chlorophyll-a concentration was calculated using the standard curve.
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