AMT13 Heterotrophic nanoflagellates sampled by CTD bottle
Originator's Protocol for Data Acquisition and Analysis
Water samples were collected from the six main light depths during the pre-dawn CTD cast using the Sea-Bird CTD rosette system. Between 100 and 200 ml of water was collected directly from the Niskin bottle and fixed with 0.3% final concentration of glutaraldehyde. Cells were stained with DAPI for 5 min, counterstained with proflavin and concentrated on 0.8 µm black carbonate filter, using a backing filter to enhance even distribution of cells. Filters were mounted on a glass slide with a small drop of immersion oil between the filter and the coverslip. Slides were frozen for analysis at PML after the cruise.
Samples were analysed by inverted epifluorescence microscopy, sized and counted using Image Pro V 5.0. This analysis provides abundance and biomass data for cells in the size range 2-20 µm. Heterotrophic forms were distinguished from autotrophic forms by the absence of chlorophyll. Chlorophyll shows up with a red fluorescence with this technique. The analysis also includes heterotrophic dinoflagellates <20 µm. The volume of the cells was converted to biomass using 200 fg C µm -3 as the carbon conversion factor.
References Cited
Instrumentation Description
Not applicable for this data set.
BODC Data Processing Procedures
Data were submitted via email in an Excel spreadsheet containing the data from AMT13 and AMT16 that was archived under BODC's accession number PML070056. Sample metadata were checked against information held in the database and the cruise report - there were no discrepancies.
Parameter codes defined in BODC parameter dictionary were assigned to the variables. The abundance data were provided as cells per millilitre and the biomass data were provided as micrograms per litre, which were consistent with the units for the relevant parameters in the BODC database.
The data were reformatted and loaded in BODC's samples database under Oracle Relational Database Management System. Data were marked up with BODC parameter codes and loaded into the database. Individual samples were matched by cast and depth.
A parameter mapping table is provided below;
| Originator's Parameter | Units | Description | BODC Parameter Code | Units | Comments |
|---|---|---|---|---|---|
| Abundance | cells ml -1 | Abundance of flagellate [Size: 2-20µm Subgroup: heterotrophic] per unit volume of the water body by DAPI/proflavine staining and epifluorescence microscopy | P400E00B | cells ml -1 | n/a |
| Biomass | µg C l -1 | Carbon biomass of flagellate [Size: 2-20µm Subgroup: heterotrophic] per unit volume of the water body by DAPI/proflavine staining and epifluorescence microscopy and abundance to carbon conversion by unspecified algorithm | C400E00B | mg C m -3 | No unit conversion necessary as units are equivalent |
Data Quality Report
BODC were not advised of specific quality checks carried out by the data originator.
Problem Report
Not relevant to this data set.
