Metadata Report for BODC Series Reference Number 1353646


Metadata Summary

Data Description

Data Category Water sample data
Instrument Type
NameCategories
Niskin bottle  discrete water samplers
Instrument Mounting lowered unmanned submersible
Originating Country United States
Originator Dr Claire Mahaffey
Originating Organization University of Southern California, USA
Processing Status banked
Project(s) Atlantic Meridional Transect (AMT)
 

Data Identifiers

Originator's Identifier AMT10_CTD_NUTS_252:AMT10-25
BODC Series Reference 1353646
 

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm) 2000-04-26 01:06
End Time (yyyy-mm-dd hh:mm) -
Nominal Cycle Interval -
 

Spatial Co-ordinates

Latitude 12.46872 N ( 12° 28.1' N )
Longitude 20.65577 W ( 20° 39.3' W )
Positional Uncertainty Unspecified
Minimum Sensor Depth 10.3 m
Maximum Sensor Depth 199.9 m
Minimum Sensor Height -
Maximum Sensor Height -
Sea Floor Depth -
Sensor Distribution Unspecified -
Sensor Depth Datum Unspecified -
Sea Floor Depth Datum Unspecified -
 

Parameters

BODC CODE Rank Units Short Title Title
ADEPZZ01 1 Metres DepBelowSurf Depth below surface of the water body
BOTTFLAG 1 Dimensionless C22_flag Sampling process quality flag (BODC C22)
NTRZAAD1 1 Micromoles per litre NO3+NO2_GF/FFilt_ColAA Concentration of nitrate+nitrite {NO3+NO2} per unit volume of the water body [dissolved plus reactive particulate
PHOSAAD1 1 Micromoles per litre PO4_GF/FFilt_ColAA Concentration of phosphate {PO43- CAS 14265-44-2} per unit volume of the water body [dissolved plus reactive particulate
SAMPRFNM 1 Dimensionless SampRef Sample reference number
SDNZAAD1 1 Micromoles per litre NO3+NO2SD Concentration standard deviation of nitrate+nitrite {NO3+NO2} per unit volume of the water body [dissolved plus reactive particulate
SDPHAAD1 1 Micromoles per litre SDPO4 Concentration standard deviation of phosphate {PO43- CAS 14265-44-2} per unit volume of the water body [dissolved plus reactive particulate
 

Definition of Rank

  • Rank 1 is a one-dimensional parameter
  • Rank 2 is a two-dimensional parameter
  • Rank 0 is a one-dimensional parameter describing the second dimension of a two-dimensional parameter (e.g. bin depths for moored ADCP data)

Problem Reports

No Problem Report Found in the Database


Data Access Policy

Open Data supplied by Natural Environment Research Council (NERC)

You must always use the following attribution statement to acknowledge the source of the information: "Contains data supplied by Natural Environment Research Council."


Narrative Documents

Niskin Bottle

The Niskin bottle is a device used by oceanographers to collect subsurface seawater samples. It is a plastic bottle with caps and rubber seals at each end and is deployed with the caps held open, allowing free-flushing of the bottle as it moves through the water column.

Standard Niskin

The standard version of the bottle includes a plastic-coated metal spring or elastic cord running through the interior of the bottle that joins the two caps, and the caps are held open against the spring by plastic lanyards. When the bottle reaches the desired depth the lanyards are released by a pressure-actuated switch, command signal or messenger weight and the caps are forced shut and sealed, trapping the seawater sample.

Lever Action Niskin

The Lever Action Niskin Bottle differs from the standard version, in that the caps are held open during deployment by externally mounted stainless steel springs rather than an internal spring or cord. Lever Action Niskins are recommended for applications where a completely clear sample chamber is critical or for use in deep cold water.

Clean Sampling

A modified version of the standard Niskin bottle has been developed for clean sampling. This is teflon-coated and uses a latex cord to close the caps rather than a metal spring. The clean version of the Levered Action Niskin bottle is also teflon-coated and uses epoxy covered springs in place of the stainless steel springs. These bottles are specifically designed to minimise metal contamination when sampling trace metals.

Deployment

Bottles may be deployed singly clamped to a wire or in groups of up to 48 on a rosette. Standard bottles have a capacity between 1.7 and 30 L, while Lever Action bottles have a capacity between 1.7 and 12 L. Reversing thermometers may be attached to a spring-loaded disk that rotates through 180° on bottle closure.

AMT10 TDN, TDP, Dissolved Inorganic Nitrogen, Soluble Reactive Phosphate, Particulate 15N isotopic composition, chlorophyll a, POC and PON

Originator's Protocol for Data Acquisition and Analysis

These data originate from analysis of seawater samples collected from both CTD bottle samples and CTD samples between 12 April and 08 May 2000. TDN, DIN (Nitrate+Nitrite (NO 3 +NO 2 )), TDP and SRP (PO 4 ) originate from analyses of samples from CTD bottles. Particulate chlorophyll-a, POC, PON and isotopic N composition samples originate from both discrete underway samples and CTD bottle samples.

For the analysis of dissolved matter, seawater samples were obtained from each depth of the 18 CTD casts deployed during AMT10. Samples were collected in 250 mL glass flasks with glass stoppers which were rinsed 3 times with sample seawater prior to sample collection. Samples were filtered through pre-combusted (450°C for 12 hours) GF/F filters. After discarding the first ~100 mL, a sample of ~100 mL seawater was collected in 150 mL flat amber medicine bottles with PTFE lined polycarbonate caps and stored at -80°C. Concentrations of nitrate and phosphate were determined using a Skalar San plus segmented flow nutrient autoanalyzer and standard colorimetric techniques. TDN and TDP concentrations were determined from analysis of NO 3 and PO 4 after ultraviolet oxidation for 2 hours using a Metrohm 705 UV digestion system. The samples were irradiated in 10 mL quartz glass tubes with graphite stoppers at a temperature of 85.C. The UV photooxidised samples were then processed through a continuous flow autoanalyser and standard colorimetric technique applied (Mahaffey et al., 2004).

Chlorophyll-a concentrations from the non-toxic seawater supply were determined by filtration of seawater (2.1 to 4.2 L) followed by onboard fluorometric analysis. POC and PON concentrations were determined using a Carlo Erba (NC 2500) elemental analyzer.

Analysis of stable nitrogen isotopic content was performed using standard elemental analyzer isotope ratio mass spectrometer (EA-IRMS) techniques. Sub-samples of freeze dried, 150 mm, glass fiber filters were randomly selected and homogenized using a pestle and mortar. The d15N PON was determined using an online system consisting of a Carlo Erba EA coupled to a Finnigan Delta CIRMS.

References Cited

Mahaffey C., Williams R.G., Wolff G.A. and Anderson W.T., 2004. Physical supply of nitrogen to phytoplankton in the Atlantic Ocean. Global biogeochemical Cycles, 18, GB1034, doi:10.1029/2003GB002129.

Instrumentation Description

Skalar Sanplus segmented flow nutrient autoanalyzer, Carlo Erba (NC 2500) elemental analyzer, Finnigan Delta CIRMS and a Metrohm 705 UV digestion system.

BODC Data Processing Procedures

Data were submitted to BODC in Microsoft Excel spreadsheet format. Sample metadata were checked against information held in the database - there was one discrepancy. For AMT10-24, the depths provided were 125 m and 150 m. As no bottle was fired at 125 m and other data files contain 150 m and 200 m entries only, the data were loaded with depths 150 m and 200 m respectively.

For 5 particulate samples, multiple depths (for example 7 + 25 m) were provided alongside one set of data. In these instances water samples from seperate depths were pooled for analyses and provided one value for the POC/N and chl-a parameters. The same data values for each parameter have been loaded for each of the sample depths that were pooled. These values have been flagged to draw attention to the data. There is one repeat sample for the particulate CTD data, the average and standard deviation have been loaded to the database. The DON and DOP data provided were not loaded to the database as they were derived from the measured variables and nutrient data.

Parameter codes defined in the BODC parameter dictionary were assigned to each variable. The data were provided in units which were consistent with those used for the relevant parameters in the BODC database. Data were loaded into BODC's database using established BODC data banking procedures.

A parameter mapping table is provided below;

Originator's Parameter Units Description BODC Parameter Code Units Comments
mean TDN µmol l -1 Concentration of nitrogen (total) per unit volume of the water body [dissolved plus reactive particulate <GF/F phase] by filtration, oxidation and colorimetric autoanalysis NTOTWCD1 µmol l -1 -
stdev TDN µmol l -1 Concentration standard deviation of nitrogen (total) per unit volume of the water body [dissolved plus reactive particulate <GF/F phase] by filtration, oxidation and colorimetric autoanalysis SDNTWCD1 µmol l -1 -
mean TDP µmol l -1 Concentration of phosphorus (total) per unit volume of the water body [dissolved plus reactive particulate <GF/F phase] by filtration, oxidation and colorimetric autoanalysis TPHSWCD1 µmol l -1 -
stdev TDP µmol l -1 Concentration standard deviation of phosphorus (total) per unit volume of the water body [dissolved plus reactive particulate <GF/F phase] by filtration, oxidation and colorimetric autoanalysis SDTPWCD1 µmol l -1 -
mean DIN µmol l -1 Concentration of nitrate+nitrite {NO 3 +NO 2 } per unit volume of the water body [dissolved plus reactive particulate <GF/F phase] by filtration and colorimetric autoanalysis NTRZAAD1 µmol l -1 -
stdev DIN µmol l -1 Concentration standard deviation of nitrate+nitrite {NO 3 +NO 2 } per unit volume of the water body [dissolved plus reactive particulate <GF/F phase] by filtration and colorimetric autoanalysis SDNZAAD1 µmol l -1 -
mean SRP µmol l -1 Concentration of phosphate {PO 4 } per unit volume of the water body [dissolved plus reactive particulate <GF/F phase] by filtration and colorimetric autoanalysis PHOSAAD1 µmol l -1 -
stdev SRP µmol l -1 Concentration standard deviation of phosphate {PO 4 } per unit volume of the water body [dissolved plus reactive particulate <GF/F phase] by filtration and colorimetric autoanalysis SDPHAAD1 µmol l -1 -
Chlorophyll-a µg L -1 Concentration of chlorophyll-a {chl-a} per unit volume of the water body [particulate >GF/F phase] by filtration, acetone extraction and fluorometry CPHLFLP1 mg m -3 -
Chlorophyll-a std dev µg L -1 Concentration standard deviation of chlorophyll-a {chl-a} per unit volume of the water body [particulate >GF/F phase] by filtration, acetone extraction and fluorometry CLSDFLP1 mg m -3 -
POC µmol l -1 Concentration of carbon (organic) {POC} per unit volume of the water body [particulate >GF/F phase] by filtration, acidification and elemental analysis CORGCAP1 µmol l -1 -
POC std dev µmol l -1 Concentration standard deviation of carbon (organic) {POC} per unit volume of the water body [particulate >GF/F phase] by filtration, acidification and elemental analysis SDCORGP1 µmol l -1 -
PON µmol l -1 Concentration of nitrogen (total) {'PON'} per unit volume of the water body [particulate >GF/F phase] by filtration and elemental analysis NTOTCNP1 µmol l -1 -
PON std dev µmol l -1 Concentration standard deviation of nitrogen (total) {'PON'} per unit volume of the water body [particulate >GF/F phase] by filtration and elemental analysis SDNTOTP1 µmol l -1 -
D15N PON Parts per thousand Enrichment of 15N in total nitrogen in the water body [particulate >GF/F phase] by filtration, combustion and mass spectrometry D15NMTP1 Parts per thousand -
D15N PON std dev Parts per thousand Enrichment standard deviation of 15N in total nitrogen in the water body [particulate >GF/F phase] by filtration, combustion and mass spectrometry SD15MTP1 Parts per thousand -

Data Quality Report

BODC has not been advised of any QC checks performed by the data originator before submission to BODC.

For 5 particulate samples, multiple depths (for example 7 + 25 m) were provided alongside one set of data. In these instances water samples from seperate depths were pooled for analyses and provided one value for the POC/N and chl-a parameters. The same data values for each parameter have been loaded for each of the sample depths that were pooled. These values have been flagged to draw attention to the data.

Problem Report

Not relevant to this data set.


Project Information

The Atlantic Meridional Transect (AMT) - Phase 1 (1995-2000)

Who was involved in the project?

The Atlantic Meridional Transect (AMT) programme was designed by and implemented as a collaboration between Plymouth Marine Laboratory (PML) and Southampton Oceanography Centre (SOC). The programme was hosted by Plymouth Marine Laboratory and involved additional researchers from UK and international universities throughout its duration.

What was the project about?

When AMT began in 1995 the programme provided a platform for international scientific collaboration, including the calibration and validation of SeaWiFs measurements and products. The programme provided an exceptional opportunity for nationally and internationally driven collaborative research and provided a platform for excellent multi-disciplinary oceanographic research. As an in situ observation system, the data collected by the AMT consortium informed on changes in biodiversity and function of the Atlantic ecosystem during this period of rapid change to our climate and biosphere.

The scientific aims were to assess:

When was the project active?

The first phase of the AMT programme ran from 1995 to 2000 and consisted of a total of 12 cruises. A second phase of funding allowed the project to continue for the period 2002 to 2006 with a further 6 cruises.

Brief summary of the project fieldwork/data

The AMT programme undertook biological, chemical and physical oceanographic research during the annual return passage of the RRS James Clark Ross between the UK and the Falkland Islands or the RRS Discovery between the UK and Cape Town, a distance of up to 13,500 km. This transect crossed a range of ecosystems from sub-polar to tropical and from euphotic shelf seas and upwelling systems to oligotrophic mid-ocean gyres. The transect route was covered north-south in September/October and south-north in April/May of each year.

The measurements of hydrographic and bio-optical properties, plankton community structure and primary production completed on the first 12 transects (1995-2000) represent the most coherent set of repeated biogeochemical observations over ocean basin scales. This unique dataset has led to several important discoveries concerning the identification of oceanic provinces, validation of ocean colour algorithms, distributions of picoplankton, identifying new regional sinks of pCO2 and variability in rates of primary production and respiration.

Who funded the project?

The programme was funded by the Natural Environment Research Council (NERC) and further support was received from the National Aeronautics and Space Administration (NASA) with equipment and funding from the Sea-viewing Wild Field-of-view Sensor (SeaWiFS) project.


Data Activity or Cruise Information

Cruise

Cruise Name JR20000412 (AMT10, JR49)
Departure Date 2000-04-12
Arrival Date 2000-05-08
Principal Scientist(s)Chris Gallienne (Plymouth Marine Laboratory)
Ship RRS James Clark Ross

Complete Cruise Metadata Report is available here


Fixed Station Information


No Fixed Station Information held for the Series


BODC Quality Control Flags

The following single character qualifying flags may be associated with one or more individual parameters with a data cycle:

Flag Description
Blank Unqualified
< Below detection limit
> In excess of quoted value
A Taxonomic flag for affinis (aff.)
B Beginning of CTD Down/Up Cast
C Taxonomic flag for confer (cf.)
D Thermometric depth
E End of CTD Down/Up Cast
G Non-taxonomic biological characteristic uncertainty
H Extrapolated value
I Taxonomic flag for single species (sp.)
K Improbable value - unknown quality control source
L Improbable value - originator's quality control
M Improbable value - BODC quality control
N Null value
O Improbable value - user quality control
P Trace/calm
Q Indeterminate
R Replacement value
S Estimated value
T Interpolated value
U Uncalibrated
W Control value
X Excessive difference

SeaDataNet Quality Control Flags

The following single character qualifying flags may be associated with one or more individual parameters with a data cycle:

Flag Description
0 no quality control
1 good value
2 probably good value
3 probably bad value
4 bad value
5 changed value
6 value below detection
7 value in excess
8 interpolated value
9 missing value
A value phenomenon uncertain