Acceptance and utilization of LTER data requires that:
FILE NAME:
PRINCIPAL INVESTIGATOR: OTHERS: KEYWORDS: photosynthetic active radiation, light, extinction coefficient, lake, limnology, Antarctica
ABSTRACT: As part of the Long Term Ecological Research (LTER) project in the McMurdo Dry Valleys of
Antarctica, lakes were monitored for photosynthetic active radiation (PAR) levels. This data set quantifies
instantaneous underwater PAR at 10-meter depths in Lakes Bonney and Hoare, and a 7-meter depth in Lake Fryxell.
Ambient PAR was also measured at the air-ice interface from each of these lakes.
VARIABLES: location name, location code, limno run, date/time, depth (m),
UwPAR (µmol photons m-2 s-1), ambient PAR (µmol photons m-2 s-1),
UwPAR (mol photons m2 hr-1), comments, file name
RESEARCH LOCATION: Samples were collected from the East Lake Bonney, West Lake Bonney, Lake Hoare, and Lake
Fryxell limnological sampling stations, located in the McMurdo Dry Valleys of Antarctica. Descriptions of these lakes
can be found in the McMurdo Dry Valley Lake
Descriptions file.
METHODS: A Licor LI-193SA spherical quantum sensor and a LI-190SA flat sensor
were attached to a Licor LI-1000 data logger to record underwater PAR and ambient PAR.
Underwater PAR data was recorded in a sampling hole covered by a Weatherport, whereas
ambient PAR was measured approximately 3 m away from the Weatherport. Logged PAR data
was recorded either as instantaneous PAR (µmol photons m-2 s-1) on a
10 minute interval, or integrated PAR (mol photons m-2 hr-1) on a 10
minute interval.
TIMING: Instantaneous data was collected at 10-minute intervals during the following periods: CITATIONS:
COMMENTS:
STATUS: Public Access (Type 1).
VARIABLE DESCRIPTION:
VARIABLE TYPE DESCRIPTION UNITS MISSING VALUE INDICATOR MINIMUM MAXIMUM PRECISION Location Name Text Name of lake where measurement was made none Required entry n/a n/a n/a Location Code Text Code for site where measurement was made none Required entry n/a n/a n/a Limno Run Text Code for lake's sampling location and date none Required entry n/a n/a n/a Collection Date/Time Date Date and time at which sample was gathered mm/dd/yy hh:mm:ss Required entry 01/01/93 00:00:00 AM 12/31/99 12:59:59 PM mm Depth (m) Number Distance below ice from which sample was drawn meters Required entry 1 60 1 uwPAR (µmol photons/m2/s) Number Underwater photosynthetically active radiation µmol photons/m2/second Null 0 100 0.001 Ambient PAR (µmol photons/m2/s) Number Ambient photosynthetically active radiation µmol photons/m2/second Null 0 2000 0.01 Comments Text Helpful hints about the sample Null n/a n/a n/a File Name Text Name of file in which data was submitted Null n/a n/a n/a LOG: Data from these tables 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 ascii text files submitted.
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. Because 2 different approaches were taken in collecting this data (instantaneous PAR
& integrated PAR), resulting in measurements that differed in scale (µmol photons/m2/second
vs. mol photons m-2 hr-1) and dates (limno run 2 vs limno run 1 of season), the data
was separated into 2 files: instantaneous measurements and integrated measurements.
These files were imported into Microsoft Access on INSTAAR's Unix system,
and can currently be found there. The files were then exported in ascii, comma delimited
text and MS-DOS text (table layout) on the MCM LTER web site. Each of these files are
linked to this web page above.
Information for the metadata was obtained from the Metaparlogged9697.rtf and
Metaparlogged9798.rtf files. The files were called up using Microsoft Word version 6.0.
Text from these files was used to create this page in html format.
While processing the 1997-98 data, the data manager noticed that the
integrated PAR data contained a jump in the dates provided for the
Lake Hoare records. Data collected in limno run HOA9798L1 contained
11/15/1997 and 12/16/1997 dates. Since there is not usually a gap like this
for a given limnology run, a correction was necessary. John Priscu and Craig Wolf were
contacted in November 1999 to look into this, but since it was the middle
of the field season, it took some time to resolve it. On 28-Feb-2000, the HOA9798L1 records
showing dates of 12/16/1997 were corrected to 11/16/1997.
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.
LOCATION STARTING / ENDING TIME
____________________________________________________________________________________
Lake Fryxell 26-Oct-1996 11:30 AM thru 27-Oct-1996 11:20 AM
19-Nov-1996 8:10 AM thru 20-Nov-1996 8:00 AM
29-Dec-1997 8:35 AM thru 30-Dec-1997 8:25 AM
28-Oct-1998 8:50 AM thru 29-Oct-1998 8:20 AM
23-Nov-1998 7:50 AM thru 24-Nov-1998 7:40 AM
20-Dec-1998 8:40 AM thru 21-Dec-1998 8:30 AM
30-Oct-1999 8:30 AM thru 31-Oct-1999 8:30 AM
27-Nov-1999 8:25 AM thru 28-Nov-1999 8:25 AM
23-Dec-1999 8:20 AM thru 24-Dec-1999 8:20 AM
West Lake Bonney 1-Nov-1996 10:00 AM thru 2-Nov-1996 9:10 AM
27-Nov-1996 8:10 AM thru 28-Nov-1996 9:00 AM
22-Dec-1997 9:15 AM thru 23-Dec-1997 8:25 AM
11-Nov-1998 9:55 AM thru 12-Nov-1998 9:25 AM
1-Jan-1999 9:40 AM thru 2-Jan-1999 9:30 AM
11-Nov-1999 8:40 AM thru 12-Nov-1999 8:40 AM
5-Dec-1999 9:00 AM thru 6-Dec-1999 9:00 AM
30-Dec-1999 9:00 AM thru 31-Dec-1999 9:00 AM
East Lake Bonney 3-Nov-1996 8:50 AM thru 4-Nov-1996 8:40 AM
24-Nov-1996 8:10 AM thru 25-Nov-1996 8:00 AM
9-Nov-1998 8:50 AM thru 10-Nov-1998 8:40 AM
30-Dec-1998 9:30 AM thru 31-Dec-1998 9:20 AM
6-Nov-1999 8:10 AM thru 7-Nov-1999 8:30 AM
3-Dec-1999 8:10 AM thru 4-Dec-1999 8:20 AM
28-Dec-1999 8:50 AM thru 29-Dec-1999 8:50 AM
Lake Hoare 8-Nov-1996 9:30 AM thru 9-Nov-1996 8:50 AM
2-Dec-1996 8:10 AM thru 3-Dec-1996 9:00 AM
26-Dec-1997 8:40 AM thru 27-Dec-1997 8:30 AM
3-Nov-1998 8:20 AM thru 4-Nov-1998 8:10 AM
1-Dec-1998 8:00 AM thru 2-Dec-1998 7:50 AM
26-Dec-1998 9:20 AM thru 27-Dec-1998 9:10 AM
17-Nov-1999 8:30 AM thru 18-Nov-1999 8:40 AM
12-Dec-1999 8:50 AM thru 13-Dec-1999 9:00 AM
____________________________________________________________________________________
Integrated data was collected at 10-minute intervals during the following periods:
LOCATION STARTING / ENDING TIME
____________________________________________________________________________________
Lake Fryxell 18-Nov-1997 8:25 AM thru 19-Nov-1997 8:15 AM
West Lake Bonney 11-Nov-1997 11:00 AM thru 12-Nov-1997 10:50 AM
East Lake Bonney No Data Available
Lake Hoare 15-Nov-1997 9:25 AM thru 16-Nov-1997 9:15 AM
____________________________________________________________________________________
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