lake

Underwater Photosynthetically Active Radiation (PAR) from in-situ Lake Primary Production Experiments in the McMurdo Dry Valleys of Antarctica (1995-2023, ongoing)

Abstract: 

As part of the Long Term Ecological Research (LTER) project in the McMurdo Dry Valleys of Antarctica, PAR is measured at one depth during primary production experiments in Dry Valley Lakes. This data set quantifies instantaneous underwater PAR at 10-meter depths in Lakes Bonney and Hoare, and at 7-meter depth in Lake Fryxell (depths vary after 2008, check data file for actual depth). Ambient PAR was also measured at the air-ice interface from each of these lakes.

Dataset ID: 

3001

Associated Personnel: 

1196
802
698
699

Short name: 

PAR_INSTANT

Locations: 

East Lake Bonney
Lake Fryxell
Lake Hoare
Lake Miers
West Lake Bonney

Data sources: 

PAR_INSTANT

Methods: 

A Licor LI-193SA spherical quantum sensor and a LI-190SA flat sensor are attached to a Licor LI-1000 data logger to record underwater PAR and ambient PAR. Underwater PAR data are recorded in the sampling hole covered by the Weatherport, whereas ambient PAR is measured approximately 10 m away from the Weatherport.

The Licor LI-1000 queries ambient and underwater PAR at 5 second intervals an records mean PAR data (micromol photons m-2 s-1) every 10 minutes.

We began using a LI-1400 at the start of the 1213 season. The Licor LI-1400 queries ambient and underwater PAR at 5 second intervals and records mean PAR data (micromol photons m-2 s-1) every 5 minutes.

Starting in the 23/24 season, the LI-1400 datalogger was replaced with a LI-1500 datalogger. Due to increased memory in the new datalogger, we now average both parameters every 60 seconds and log every 60 seconds. Previously, the LI-1400 used a sampling period of 5 seconds and a logging period of 5 minutes.

Additional notes:

  • EB0304L1: McKenna: no data available. LICOR was turned off by accident
  • FRX0405L2: No logged PAR data for FRX L2. FRX L2: 1 Dec 04 (0744): PPR incubation put in water; 2 Dec 04 (0815): PPR incubation taken out of water.
  • HOR2223L2: no HOR L2 measurements (no PPR incubation)

Maintenance: 

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 two different approaches were taken in collecting this data (instantaneous PAR and integrated PAR), resulting in measurements that differed in scale (micromol 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 two 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. 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. In 2006, Chris Gardner and Inigo San Gil converted all metadata to EML to comply with interoperability mandates at LTER. In 2014, Inigo San Gil introduced metadata enhancements (publication Date, methods, markup, language, entity level, etc) and placed the metadata into the Drupal Ecological Information Management System.

Additional information: 

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