North Temperate Lakes LTER: Color - Trout Lake Area 1989 - current
Abstract
Color is measured four times per year in the seven northern study lakes (Allequash, Big Muskellunge, Crystal, Sparkling, and Trout lakes, unnamed lakes 27-02 [Crystal Bog] and 12-15 [Trout Bog]) on water samples that are filtered in the field through 0.45 micron capsule filters (0.45 um nuclepore membrane filters before 2015). A spectrophotometer is used to quantify color in the lab as absorbance units, at 1nm intervals between the wavelengths of 200 and 800 nm. All values are given as measurements at the path length of the employed cuvette and should be divided by the cuvette length for a comparable value at a pathlength of 1 cm. Sampling Frequency: 4 times annually. Number of sites: 7.
Contact
Dataset ID
87
Data Sources
Date Range
-
Maintenance
ongoing
Metadata Provider
Methods
Water samples for color are collected at the deepest part of the lake four times per year: February under ice, spring mixis, August stratification, and fall mixis. The samples are surface water collected with a peristaltic pump and tubing, filtered in the field through 0.45 micron capsule filters ( 0.45u polycarbonate membrane filters before 2015). A wavelength scan from 800 to 200nm is run, using a 5cm rectangular quartz cell in a Beckman Coulter Model DU800 single beam spectrophotometer. Any samples that display absorbance values above 2AU are run again from 400 to 200nm using a 1cm quartz cuvette, as values above 2AU are not considered valid. Blank values in the dataset are from a deionized water scan run as a first sample after instrument blanking, and are reported alongside the scans but are not subtracted from the scan values.
Protocol Log: 1990 -- Scans run using a 10cm cylindrical cell on a Kontron spectrophotometer. 2001 -- we added scans in a 1cm cell for samples with absorbance greater than 2AU. July 2008 -- changed to Beckman Coulter DU800 spectrophotometer, and changed from 10cm to 5cm cell.
Protocol Log: 1990 -- Scans run using a 10cm cylindrical cell on a Kontron spectrophotometer. 2001 -- we added scans in a 1cm cell for samples with absorbance greater than 2AU. July 2008 -- changed to Beckman Coulter DU800 spectrophotometer, and changed from 10cm to 5cm cell.
NTL Themes
Project
Short Name
NTLPH07
Version Number
32