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AMT12 extracted chlorophyll-a measured fluormetrically from CTD bottle samples

Data Acquisition and Analysis

This data originates from analyses on samples collected from CTD rosette bottles for 56 CTD casts.

Water samples from the 5-6 main light depths were collected from CTD bottles and were filtered on 25 mm GFF filters. Filters were extracted in 90% acetone for 24 hrs and total chlorophyll-a measured with a TD-700 Turner Designs fluorometer following the procedure of Welschmeyer (1994) which minimises interference by chlorophyll-b. The fluorometer was calibrated with dilutions of a solution of pure chlorophyll-a (Sigma, UK) in 90% acetone, the concentration of which was determined spectrophotometrically after the cruise.

References Cited

Welschmeyer N.A., 1994. Fluorometric analysis of chlorophyll-a in the presence of chlorophyll-b and phaeopigments. Limnology and Oceanography, 39, 1985-1992.

Instrumentation Description

Not relevant to this dataset.

BODC Data Processing Procedures

Data were submitted to BODC in an Excel spreadsheet and were accessioned under BODC archive SOC040010. Sample metadata provided (CTD cast, date, time, lat/lon and depth) were checked against information held in the database. There were no discrepancies noted.

Parameter codes defined in BODC parameter dictionary were assigned to the variable. The units supplied in the spreadsheet were mg m ^-3 , which match the Parameter Dictionary units so no unit conversions were necessary.

Data loaded into BODC's database without any changes applied.

A parameter mapping table is provided below;

Data Quality Report

There was no indication that the dataset had been checked by the data origniator prior to submission to BODC.

Problem Report

Not relevant to this dataset.