HPLC_BBSR

Dataset description

High Performance Liquid Chromatography (HPLC) pigment data from the CARIACO time series stations and analyzed at Mote Marine Laboratory

Acquisition description

Water for the HPLC filters is collected from the first cast done during the CARIACO core cruises (CXXX_1_4), carried out around 5 am local time. During periods of low primary production, 2000 ml. of water are vacuum filtered through a 47mm GF/F filter pad. During periods of high primary production, water is filtered until the filter is clogged. The volume of water filtered is annotated. Eight depths are sampled: 1, 7, 15, 25, 35, 55, 75 and 100m. If a deep chlorophyll maximum is found at a different depth, this depth is also sampled. A duplicate is taken at one of these depths (usually at 1m), for QA/QC assessment. Filters are carefully folded in half, stored in aluminum foil and refrigerated until reaching shore. Once back on shore, they are stored frozen at -40°C. Filters are transported from Margarita Island to USF and stored frozen (at -40°C) until they are shipped to Bermuda Biological Research Station for analysis. Filters are frozen in liquid nitrogen for shipment.

Processing description

BCO-DMO processing notes

Pigment data taken during CARIACO cruises 2 through 30 were submitted to BCO-DMO as Microsoft Excel™ spreadsheets. Analysis for this series of cruises was performed at Bermuda Biological Station for Research (BBSR.)

These data cover the period between December 1995 and April 1998. For cruises 16 and 21, an additional cruise took place 8 days later, bringing the number of spreadsheets submitted to thirty one. Pigment measurements included chlorophyll-a, chlorophyll-b, total chlorophyll-c1 and -c2, chlorophyll-c3 , Chlorophyllide-a, alpha Carotene, beta Carotene, 19' - Butanoyloxyfucoxanthin, 19' - Hexanoyloxyfucoxanthin, Fucoxanthin, Diadinoxanthin, Alloxanthin, Diatoxanthin, Lutein, Peridinin, Prasinoxanthin, Zeaxanthin, Turner fluorometer-measured chlorophyll-a, and Turner fluorometer-measured Pheopigments. All HPLC measurements were provided in nanograms per liter.

Field names used in the original spreadsheets were translated to BCO-DMO parameter names. See BBSR Parameter Conversion Table for details. Values reported as ND (not detected) in the spreadsheets are reported here as 0. Values reported as NM (not measured) in the original spreadsheets are reported here as nd (no data). Data not included in the spreadsheets (leg, cast, and cast time) were provided in a separate file (cast details) by Laura Laurenzoni, CARIACO Data Manager (IMaRS, USF.) While the cruise numbers match cruise numbers for other CARIACO time-series data, the dates are not identical.

Conversion of the spreadsheets to a format compatible with the BCO-DMO database was performed using unix shell scripts and PERL scripts. Original files were manually edited as necessary to provide the computer programs with consistent input. This editing was relatively minor, involving filling in empty cells, eliminating troublesome punctuation, and standardizing inconsistent input. These edits were critical to processing the spreadsheets as a unit. In a very few cases, it was necessary to add information. See BCO-DMO_modifications_to_BBSR.pdf for details.

It is recommended that caution be exercised when using pigment data from the three Cariaco HPLC datasets since definitions have changed over the years since the data collection and analysis began. Every effort was made by this office to properly label data fields, however, if questions on data content arise, original spreadsheet data should be consulted.

Since the units used for reporting the data changed after this set was analyzed (at cruise 39) and, it was felt that the data would be easier to use with consistent units, it was decided that they should be made uniform. Therefore, CARIACO Data Manager Laura Lorenzoni standardized volume of water filtered to milliliters and all HPLC values to micrograms per liter, using the BCO-DMO-formatted files as input.

This document is created from the content of the BCO-DMO metadata database.    2010-03-19  07:31:21