HPLC_HPL

Dataset description

High Performance Liquid Chromatography (HPLC) pigment data from the CARIACO time series stations and analyzed at Horn Point Laboratory (HPL)

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 Horn Point Laboratory (HPL) for analysis. Filters are frozen in liquid nitrogen for their shipment to HPL.

Analysis at HPL is carried out according to the method described in Hooker et al. (2005), Chapter 5.

Reference:

Hooker, S.; L. Van Heukelem; C. S. Thomas; H. Claustre, J. Ras; R. Barlow; H. Sessions; L. Schlüter; J. Perl and C. Trees; V. Stuart; E. Head; L. Clementso; J. Fishwick; C. Llewellyn and J. Aiken. 2005. The Second SeaWiFS HPLC Analysis Round-Robin Experiment (SeaHARRE-2). NASA Technical Memorandum NASA/TM-2005-212785. (PDF file)

Processing description

Once HPL provides the datasheets to the CARIACO office, HPLC Total Chlorophyll a (TChla) is compared with chla measured fluorometrically at the Time-Series shore station in Margarita Island, Venezuela. The measurements should be relatively close (R2 > 0.9). Measurement analytical precision is also looked at and noted if it is significantly different from what HPL reports for their variables. If there are any significant issues with shipping/filter quality that affect the data, these are also noted.

The HPLC parameter names as reported in this dataset correspond to the pigment names as defined in the NASA SeaWiFS Bio-optical Archive and Storage System (SeaBASS) (http://seabass.gsfc.nasa.gov/).

BCO-DMO processing notes

Pigment data taken during CARIACO cruises 124 through 157 were submitted to BCO-DMO as ascii text files. No files were submitted for cruises 139 or 154. Analysis for this series of cruises was performed at Horn Point Laboratory (HPL) in Chesapeake, MD. These data cover the period from July 2006 through May 2009.

Pigment measurements included total chlorophyll-a, total chlorophyll-b, total chlorophyll-c, total alpha plus beta carotenoids, 19'-Butanoyloxyfucoxanthin, 19'-Hexanoyloxyfucoxanthin, Alloxanthin, Diadinoxanthin, Diatoxanthin, Fucoxanthin, Peridinin, Zeaxanthin, chlorophyll-a, Divinyl Chorophyll-a, Monovinyl Chorophyll-a, chlorophyllide a, chlorophyll-b, Divinyl Chorophyll-b, Monovinyl Chorophyll-b, chlorophyll-c1, chlorophyll-c2, chlorophyll-c1 plus -c2, chlorophyll-c3, Lutein, Neoxanthin, Violaxanthin, Pheophytin-a, Pheophorbide-a, Prasinoxanthin, Gyroxanthin-Diester, total chlorophyll, Photoprotective carotenoids, Photosynthetic carotenoids, Photosynthetic pigments, total photoprotective carotenoids plus photosynthetic carotenoids, total accessory pigments, total pigment concentration, total diagnostic pigments, ratio of total accessory pigments to total chlorophyll a, ratio of photosynthetic carotenoids to total carotenoids, ratio of photoprotective carotenoids to total carotenoids, ratio of total chlorophyll (a plus b plus c) to total carotenoids, ratio of photoprotective carotenoids to total pigments, ratio of photosynthetic pigments to total pigments, ratio of total chlorophyll a to total pigment, Microplankton proportion factor, Nanoplankton proportion factor, Picoplankton proportion factor.

In the submitted data, standard SeaBass field names were used to identify the parameters. These were translated to the corresponding BCO-DMO parameter names. Details of this translation can be found in HPL Parameter Conversion Table. Values reported as -9999.99 in the original text files are reported here as nd (no data). Except for ratios, measurements are reported in milligrams per cubic meter. While the cruise numbers match cruise numbers for other CARIACO time-series data, the dates are not identical.

Conversion of the text files to a format compatible with the BCO-DMO database was performed using unix shell scripts and PERL scripts.

1. High Performance Liquid Chromatography:

2. Niskin Bottle :

This document is created from the content of the BCO-DMO metadata database.    2010-03-18  08:28:25