PHYTOPLANKTON PRIMARY PRODUCTION IN MCMURDO DRY VALLEY LAKES

Acceptance and utilization of LTER data requires that:

• 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 at:
  as well as the Principal Investigator. For a list of MCM LTER Principal Investigators.

PRINCIPAL INVESTIGATOR: John Priscu
Address:Department of Biology, Montana State University, Bozeman MT, 59717
Phone:(406)994-3250
E-Mail:ubijp@gemini.oscs.montana.edu or JPriscu@LTERnet.edu

KEYWORDS: lake, limnology, primary production, carbon, chlorophyll, phytoplankton, Antarctica

ABSTRACT: An important part of the McMurdo Long Term Ecological Research (LTER) is monitoring of spatial and temporal patterns, and processes that control phytoplankton production in perennial ice-covered lakes. This data set addresses this core area of research and quantifies carbon production at specific depths in McMurdo Dry Valley lakes.

VARIABLES: limno run, location name, location code, date, depth (m), PPR (µg C L^-1 d^-1), PPR 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: Lake water samples were collected at specific depths with a five-liter Niskin bottle during normal LTER limnological sampling. In a darkened environment, water was decanted directly from the Niskin bottle into three-150 mL borosilicate glass bottles with Teflon screw cap liners (2-light, 1-dark). Each sample was inoculated with an appropriate volume of ¹⁴C bicarbonate (activity of working solution should be between 100-121 µCi mL^-1):

Sample bottles were attached to a depth-calibrated cable and incubated in situ for 24 hours. At the end of the incubation period, the bottles were removed from the lake and placed in a darkened box for transport to the field lab. Each sample bottle was filtered through a 25 mm Whatman GF/F filter, and placed at the bottom of a 20 mL scintillation vial (organic matter up). 0.5 mL of 3 N HCl was pipetted into each vial and dry filtered slowly on a heating block (50°C) in a fume hood. Once the filters were dry, the scintillation vials were recapped and stored until scintillation counting.

10 mL of Cytoscint cocktail was added to each vial and counted on a calibrated ¹⁴C liquid scintillation counter. Primary production (µg C L^-1 d^-1) was calculated using the following equation:

PPR = (DPM_L - DPM_D) a * b
alpha * t

where DPM_L is the average dpm of the light bottles, DPM_D is the dpm of the dark bottle, a is the concentration of dissolved inorganic carbon at the respective depth, b is a constant (1.06) to adjust for isotopic discrimination of ¹⁴C radiolabeled carbon, alpha is the total dpm of ¹⁴C added to the sample, and t is the incubation period.

TIMING: Samples were collected from the following sites and dates:

 
Season		East Bonney	West Bonney	Hoare		Fryxell
1993-1994	27-Oct-1993	29-Oct-1993			16-Nov-1993
 		10-Nov-1993	12-Nov-1993
 		24-Nov-1993	26-Nov-1993	 1-Dec-1993	 7-Dec-1993
 		 7-Dec-1993	 9-Dec-1993
 		21-Dec-1993	23-Dec-1993	30-Dec-1993	 7-Jan-1994
 													
1994-1995	 2-Nov-1994	 5-Nov-1994	10-Nov-1994	14-Nov-1994
 		23-Nov-1994	25-Nov-1994	30-Nov-1994	 4-Dec-1994
 		17-Dec-1994	19-Dec-1994	24-Dec-1994	30-Dec-1994
 		10-Jan-1995	12-Jan-1995	20-Jan-1995	17-Jan-1995
 		
1995-1996	19-Sep-1995	21-Sep-1995	 7-Sep-1995	14-Sep-1995
 						14-Sep-1995
 		 6-Oct-1995	 4-Oct-1995	25-Sep-1995	28-Sep-1995
 		17-Oct-1995	19-Oct-1995	10-Oct-1995	14-Oct-1995
 		 2-Dec-1995	 5-Dec-1995	21-Nov-1995	26-Nov-1995
 		 1-Jan-1996	 4-Jan-1996	23-Dec-1995	27-Dec-1995
 		
1996-1997	 3-Nov-1996	 1-Nov-1996	 8-Nov-1996	26-Oct-1996
 		24-Nov-1996	26-Nov-1996	 2-Dec-1996	19-Nov-1996
 		15-Jan-1997	17-Jan-1997	12-Jan-1997	 9-Jan-1997
 		
1997-1998	 8-Nov-1997	11-Nov-1997	15-Nov-1997	18-Nov-1997
		20-Dec-1997	22-Dec-1997	26-Dec-1997	29-Dec-1997

1998-1999	 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

1999-2000	 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

CITATIONS:

COMMENTS: If the dpm for the dark bottle was higher than the average dpm of the light bottles then primary production was reported as zero. Incubation times are usually 0700 hours local time to 0700 hours the following day.

STATUS: Public Access (Type 1).

VARIABLE DESCRIPTION:

VARIABLE	TYPE	DESCRIPTION	UNITS	MISSING VALUE INDICATOR	MINIMUM	MAXIMUM	PRECISION
Limno Run	Text	Code for lake's sampling location and date	none	Required entry	n/a	n/a	n/a
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
Date	Date	Date on which sample was gathered	mm/dd/yy	Required entry	01/01/93	12/31/99	dd
Depth (m)	Number	Distance below ice from which sample was drawn	meters	Required entry	1	25	1
PPR (µg C/l*d)	Number	Primary productivity, measured as inorganic carbon uptake using 14C-bicarbonate	µg Carbon/liter*day	Null	0	100	0.001
PPR Comments	Text	Helpful hints about the sample	none	Null	n/a	n/a	n/a
File Name	Text	Name of file in which data was submitted	none	Null	n/a	n/a	n/a

LOG: 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 Metappr9697.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.

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.