Metadata Report for BODC Series Reference Number 2150712

• Metadata Summary

• Problem Reports

• Data Access Policy

• Narrative Documents

• Project Information

• Data Activity or Cruise Information

• Fixed Station Information

• BODC Quality Flags

• SeaDataNet Quality Flags

Metadata Summary

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

Seapoint Chlorophyll Fluorometer

The Seapoint Chlorophyll Fluorometer (SCF) is a low power instrument for in situ measurements of chlorophyll a. The SCF uses modulated blue LED lamps and a blue excitation filter to excite chlorophyll a. The fluorescent light emitted by the chlorophyll a passes through a red emission filter and is detected by a silicon photodiode. The low level signal is then processed using synchronous demodulation circuitry which generates an output voltage proportional to chlorophyll a concentration. The SCF may be operated with or without a pump.

Sensor specifications, current at August 2006, are given in the table below. More information can be found at the manufacturer's web site.

Sensor Specifications

Turner Designs Trilogy Fluorometer

The Trilogy Laboratory Fluorometer is a compact laboratory instrument for making fluorescence, absorbance and turbidity measurements using the appropriate snap-in Application Module.

The following snap-in application modules are available:

For extracted chlorophyll measurements using EPA 445, Trilogy automatically calculates the concentration using the filtered and solvent volumes. The turbidity modules use an IRLED with a wavelength of 860nm to meet ISO 7027 standards for turbidity water quality measurements.

Specifications

Further details can be found in the manufacturer's specification sheet.

Non-toxic (underway) sea water supply

A source of uncontaminated near-surface (commonly 3 to 7 m) seawater pumped continuously to shipboard laboratories on research vessels. There is typically a temperature sensor near the intake (known as the hull temperature) to provide measurements that are as close as possible to the ambient water temperature. The flow from the supply is typically directed through continuously logged sensors such as a thermosalinograph and a fluorometer. Water samples are often collected from the non-toxic supply. The system is also referred to as the underway supply.

LOCATE Cruise CEnd 18/16 Underway Discrete Samples

Originator's Protocol for Data Acquisition and Analysis

A total of 148 water samples were taken during the LOCATE cruise CEnd 18/16 from the ship's non-toxic supply roughly every two-three hours. The samples were passed through the ship's Ferrybox system, which took measurements of temperature, chlorophyll a, salinity, and photosynthetically available radiation. Samples were measured by the Centre for Environment Fishers and Aquaculture Science (CEFAS), National Oceanography Centre (NOC), Plymouth Marine Laboratory (PML), Centre for Ecology and Hydrography (CEH), and Thermodynamic Equation of Seawater - 2010 (TEOS-10), although the TEOS-10 data was not processed. There was an issue with the navigation channel of the Ferrybox, therefore the location of these data are approximate positions calculated by the data originator.

Chlorophyll-a

Chlorophyll-a concentrations were determined fluorometrically from 250ml water samples. The water samples were then filtered through 25mm Whatman GF/F filters with a nominal pore size ~0.7mm and the pigments were then extracted in 6ml of 90% acetone at 4°C over an 18-20 hour period. Pigment extracts were measured using a Turner Designs Trilogy fluorometer following Welschmeyer (1994) and calibrated against a pure chlorophyll-a standard. The CEFAS Ferrybox chlorophyll was calibrated against the NOC chlorophyll using the equation: y=4.8106x-0.083.

Inorganic Nutrients - National Oceanography Centre

Water samples were collected, filtered through 0.2µm filters and frozen in 15 ml Falcon tubes for later analysis. Samples were analysed using a Seal Quaatro autoanalyser.

Inorganic Nutrients - Plymouth Marine Laboratory

Water samples were collected, filtered through 0.2µm filters, and frozen in 60 ml HDPE Nalgene bottles for later analysis at PML using standard procedures on a Technicon segmented flow colorimetric autoanalyser following standard procedures (e.g. Woodward and Rees (2001)).

Dissolved Organic Nitrogen and Dissolved Organic Phosphorous

Water samples were collected, filtered through 0.2µm filters for samples 1-21 and frozen in 125 ml HDPE bottles for later analysis. The inline filtration system did not work properly, and the filter frequently leaked, so there is low confidence in the filtering and the water samples were not filtered from sample 22 onward. During analysis, samples were warmed to room temperature, defrosted, and throughly mixed. Concentrations of dissolved organic nitrogen (DON) and dissolved organic phosphorous (DOP) were obtained by UV-oxidation of duplicate 10 ml aliquots using Methrohm 205 UV digestors. Samples were irradiated for 2 hours before analysis for total inorganic nitrate and phosphorous concentrations using a Seal Quaatro autoanalyser and nutrient certified reference matereials (CRM's) (from Kanso, Japan) for reference and correction following GO-SHIP recommended protocols. Concentrations of DON and DOP were obtained by difference (i.e. DON = TDN - NO3+NO2; DOP = TDP - PO4).

Dissolved Organic Carbon

Dissolved organic carbon (DOC) samples were analysed at CEH in Lancaster. Water samples were collected, filtered through 0.2µm filters for samples 1-21 and frozen in 125 ml HDPE bottles for later analysis. The inline filtration system did not work properly, and the filter frequently leaked, so there is low confidence in the filtering and the water samples were not filtered from sample 22 onward. The samples were acidified with 3M HCl and sparged with oxygen, then analysed on a Skalar Formacs analyser. Inorganic carbon is converted to CO₂ and removed. The remaining non-purgeable organic carbon (NPOC) can be regarded as DOC for waters where there are no volatile organic carbon compounds present.

Particulate Organic Nitrogen and Particulate Organic Carbon

Samples were analysed using the Southampton University EA-IRMS system. Samples were acid fumed prior to analysis to remove particulate inorganic carbon, and underwent elemental analysis before being run through the mass spectrometer. The samples were run on two different machines:

1. Vario PYRO cube elemental analyser coupled with vision isotope ratio mass spectrometer in CNS and CN modes
2. Vario ISOTOPE select elemental analyser coupled with Isoprime 100 Isotope ratio mass spectrometer in CN mode

Particulate Organic Phosphorus

Samples were analysed using the chemical digestion method of Raimbault et al (1999) and run through an autoanalyser.

Salinity

Salinity samples were analysed back at NOC using a Guildline 8410 Portasal salinometer.

References Cited

Painter, S. C. et al. (2018) Terrestrial dissolved organic matter distribution in the North Sea, Science of The Total Environment, 630, 630-647.

Raimbault, P. et al. (1999) Simultaneous determination of particulate organic carbon, nitrogen and phosphorus collected on filters, using a semi-automatic wet-oxidation method. Marine Ecology Progress Series, 180, 289-295.

Welschmeyer, N. A. (1994) Fluorometric analysis of chlorophyll a in the presence of chlorophyll b and pheopigments. Limnology and Oceanography, 39(8), 1985-1992.

Woodward, E. M. S. and Rees, A. P. (2001) Nutrient distributions in an anticyclonic eddy in the northeast Atlantic Ocean, with reference to nanomolar ammonium concentrations. Deep Sea Research Part II, 48, 775-793.

BODC Data Processing Procedures

The data were supplied to BODC in one Excel file. The data from different organisations were processed together by BODC as they originated from the same water samples, but should be considered separate datasets. The data from PML should be considered primary and the NOC data secondary.

The originator variables were mapped to appropriate BODC parameter codes as follows:

Note to User

This dataset is made freely available to allow reuse of the data and in addition to the source publication being recognised we expect and encourage that LOCATE project datasets are acknowledged in all future publications via inclusion of the LOCATE grant code in the acknowledgements. Further analysis of this data can be found in Painter et al (2018).

Data citation

If using this data, please add the following citation. "Data used in this study were supplied by the Land Ocean Carbon Transfer (LOCATE) project, a study supported by Natural Environment Research Council grant NE/N018087/1".

Other data

BODC also holds data for normalised fluorescent intensities (in Raman Units) of the 3 organic matter compounds using PARAFAC modelling analysis. However, these remain in the original format and were not ingested due to missing underlying data to support the results. There are also data derived using TEOS-10, Conservative Temperature and Absolute Salinity, that were not ingested as they are derived parameters and can be calculated from the ingested data. All of these are available upon request.

Project Information

Land Ocean CArbon TransfEr: LOCATE

LOCATE is a collaboration between the National Oceanography Centre (NOC), the Centre for Ecology and Hydrology (CEH), the British Geological Survey (BGS) and the Plymouth Marine Laboratory (PML).

LOCATE integrates knowledge and skills across NERC terrestrial, freshwater and marine research centres to transform the UK?s ability to measure, model and predict land-ocean tOM fluxes in a changing environment. It allows next-generation biogeochemical models to explore how climate change and land management decisions influence the global carbon cycle. The project has three main objectives:

• To quantify the fate of terrigeneous organic matter from soils to the ocean, with particular focus on estuaries and coastal waters.
• To quantify and understand the loss processes in estuarine environments.
• To build a new model of terrigeneous organic matter cycling valid in marine and fresh waters, and use it to predict the future evolution of the land ocean carbon flux.

LOCATE is funded by the Natural Environment Research Council (NERC) from 2016 until 2021.

Data Activity or Cruise Information

Cruise

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:

SeaDataNet Quality Control Flags

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