AMT6 Chlorophyll-a concentrations collected in connection with 14C Primary Production incubations
Originator's Protocol for Data Acquisition and Analysis
This data originates from analyses on CTD rosette bottles from 24 casts.
Samples were collected between 8:00 and 9:00 GMT each day. The downwelling CTD cast was used to determine irradiance and chlorophyll fluorescence through the water column using the Seabird 911 plus. Between five and eight depths were selected, for a detailed analysis of the water column based on percentage irradiance levels and fluorescence levels. Fractionated chlorophyll- a (chl- a ) was determined at 24 stations along AMT-6 in connection with the PP incubation samples. Between 200 and 300 ml of sea water sample from each depth in the water column were sequentially filtered through 0.2 µm, 2 µm and 20 µm polycarbonate filters. Chl- a was extracted from the filters in 90% acetone at -20 o C for 12 to 24 hours. The samples were measured on a Turner 10-AU fluorometer calibrated with pure chl- a .
References Cited
Instrumentation Description
Turner 10-AU fluorometer
BODC Data Processing Procedures
Data were submitted in an Excel spreadsheet with the AMT6 Primary Production measurements and the equivalent Primary Production and chlorophyll-a datasets from AMT1-5 and 11. The file was saved in the BODC archive with reference UVI020056. The data were supplied with the following metadata; Cruise, Latitude and Depth. The metadata were compared to the database - there were no discrepancies.
Parameter codes defined in BODC parameter dictionary were assigned to the variables. No unit conversion was necessary as the units supplied in the spreadsheet (milligrams per cubic metre) matched the units for the parameter codes in the BODC Parameter Dictionary.
The data were loaded to the database under BODC data processing procedures.
A parameter mapping table is provided below;
| Originator's Parameter | Units | Description | BODC Parameter Code | Units | Comments |
|---|---|---|---|---|---|
| CHL 0.2 µ | mg m -3 | Concentration of chlorophyll-a {chl-a} per unit volume of the water body [particulate 0.2-2um phase] by filtration, acetone extraction and fluorometry | SCHLFLPF | mg m -3 | - |
| CHL 2 µ | mg m -3 | Concentration of chlorophyll-a {chl-a} per unit volume of the water body [particulate 2-20um phase] by filtration, acetone extraction and fluorometry | SCHLFLPG | mg m -3 | - |
| CHL 20 µ | mg m -3 | Concentration of chlorophyll-a {chl-a} per unit volume of the water body [particulate >20um phase] by filtration, acetone extraction and fluorometry | SCHLFLPQ | mg m -3 | - |
| CHL TOT µ | mg m -3 | Concentration of chlorophyll-a {chl-a} per unit volume of the water body [particulate >0.2um phase] by filtration, acetone extraction and fluorometry and summation of size-fractionated values | CPHLFLP4 | mg m -3 | - |
Data Quality Report
BODC were not advised of specific quality checks carried out by the data originators. There were no standout values in the sample data provided to BODC.
Problem Report
Not relevant to this data set.
