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Arctic LTER Database

Arctic LTER Database

Acceptance and utilization of LTER data requires that:

(1) The Principal Investigator be sent a notice stating reasons for acquiring any data and a description of the publication intentions.
(2) 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.
(3) A copy of any resultant publications should be sent to:

Principal Investigator
Ecosystems Center
Marine Biological Laboratory
7 MBL St.
Woods Hole, MA 02543

Older Metadata: Attribute table not in XML (EML) file

Dataset URLs:METADATA: HTML, Rich Text, XML(EML compliant)
DATA: Comma Delimited, Excel file with Metadata and data
Dataset ID:2004e6chlr
Dataset Title:Corrected Chlorophyll a for Arctic lake E6 during the summer of 2004
Investigator 1: 
First Name:Anne
Last Name:Giblin
Address line 1:
Address line 2:
Address line 3:
Zip Code:
Associate Investigators:Chris Crockett, Lori Winters, Sam Kelsey
Abstract: Corrected Chlorophyll a for lake E6 during the summer of 2004
Contact: Arctic LTER Information Manager
The Ecosystems Center
Marine Biological Lab
7 MBL St
Woods Hole, MA 02543
Phone (508) 289 7496
Online URL:
Data File Name 2004e6chlr
Beginning Date 5/1/2004
End Date 9/1/2004
Number of Data Records
Other Files to Reference
Availability Status
Quality Control Information
Maintenance Description
Log of Changes: Log of changes: 1. A Turner 111 fluorometer was used from 1975-1991. 2. A Turner 450 Fluorometer using a NB 440 filter was used starting in 1992- 1994. 3. A Turner 450 Fluorometer using a NB 430 filter was used starting in 1995 until 1998. 4. Starting in 1998 a Turner Designs 10-Au -005 -CE configured with a chlorophyll optical kit: photomultiplier tube 185 - 870; lamp daylight white, F25T5, 400-600 nm; excitation filter 340-500 nm round bandpass 5-60; emission filter >665 nm round sharpcut 2-64; reference filter 400-700 nm square 1 ND,was used to measure chlorophyll. 5. In 2002 and 2003 comparisons were made using both Whatman GFC filters (1.2um) and GFF filters (0.7um). Additional information about this comparison can be obtained by contacting the Arctic Lakes RA, C. Crockett. 6. In 2003 samples were acidified with 100ul 1N HCL for 90 seconds to determine pheophytin concentration. Data presented represents raw chlorophyll, post acidification values can be obtained by contacting the Arctic Lakes RA, C. Crockett. 7. In 2004 samples were acidified with 300ul of 0.1N HCL for 90 seconds to correct for pheophytin and extracted at 4C. Reported values are in corrected chl a ug/L and pheophytin ug/L. Samples were filtered using Whatman GFF (0.7um) filters, GFC (1.2um) filters have been used in previous years. A detailed protocol can be found at the LTER Arctic Lakes Website. For Archival Use: DATE RECEIVED: September 2004 DATA FILE ENTERED BY: C. Crockett DATA FILE VALIDATION: NAME: 2004e6chlr.txt DATE: October 2004
Geographic Description Toolik Field Station, North Slope, Alaska.
Location Bounding Box
West Bounding Coordinate
East Bounding Coordinate
North Bounding Coordinate
South Bounding Coordinate
OR if single point location
Organisms studied

Water samples are collected at a minimum of the epi, meta, and hypolimnion, samples at other depths are collected as needed dependent on lake and conditions. Lake E1 is routinely sampled at depths 0, 1, meta, and hypolimnion. Samples are collected in 2-L brown Nalgene bottles and returned to the lab within 2 hours. Water is filtered through a 47 mm Whatman GF/F (0.7 um) glass fiber filter. Filters are placed in 10 ml of chilled, buffered (1 mg/l MgCO-3) 90% acetone and extracted in the dark at approximately 4C (iced in cooler) for 18-24 hours. Chlorophyll a was determined using a Turner Designs 10-Au -005 -CE configured with a chlorophyll optical kit (10-037R). This kit is used for the traditional in-vivo measurement of chlorophyll (Lorenzen) and in-vivo/extractive acidification methods, including Strickland and Parsons, and Standard Methods for Water and Waste Water and EPA 445.

Notes: In 2004 several adjustments were made to the protocol from 2003. Extraction took place at approximately 4C using chilled acetone. A multipoint curve was analyzed using a chl a stock std. A Turner Designs solid standard could then be utilized as a check. Additionally, chl a was corrected for pheophytin following EPA 445 and data is reported in corrected chl a. For more information please reference the chlorophyll protocol available on the Arctic LTER website.

Reference Citations: R.G. Wetzel & G.E. Likens. 1979. Limnological Methods. Saunders.

Sampling Description.


Data Table

Variable		Variable descrip.		Precis. / Units	Coded	Missing
(Y/N)	Values
Site		site code					y	n
Lake		Site of measurement				n	n
DEPTH	Depth			meters			n	n
DATE		Date			DD-MMM-YY	n	n
Chlor a	Corrected Chlorophyll a	ug/L			n	n
Pheophytin	Pheophytin 		ug/L			n	n
Notes		Notes			N/A			n	y
Variable					Formula
Chlorophyll a
C E, C  = Chlorophyll a concentration in the extract (usually 10ml)
C E, C = Fs(r/r-1)(Rb-Ra)
C E, C  = corrected chlorophyll a concentration (ug/L) in the extract solution analyzed
Fs = response factor for the sensitivity setting S
r = the before to after acidification ration of a pure chl a solution (Rb/Ra)
Rb = fluorescence of sample extract before acidification
Ra = fluorescence of sample extract after acidification
C S, C = corrected chl a concentration (ug/L) in the whole water sample
C S, C ={(C E, C x extract volume  in L x Dilution Factor)/(sample volume
in L)}
Pheophytin a
PE = pheophytin a concentration (ug/L) in the sample extract
PE = Fs (r/r-1) (rRa - Rb)
PS = pheophytin a concentration (ug/L) in the whole water sample
PS = (PE x extract volume in L x dilution factor)/(sample volume in L)
Note: if no dilution took place, then DF equals 1

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