Metadata Report for BODC Series Reference Number 2117512

• 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

Apollo Sci Tech AS-ALK2 Total Alkalinity titrator

An automated acid-base titrator for use in aquatic carbon dioxide parameter analysis. The titrator provides standardisation and sample analysis, using the Gran titration procedure for alkalinity determination of seawater and brackish waters. It is designed for both shipboard and land based laboratory use. The precision of the instrument is 0.1% or higher, and sample volumes may range from 10-25 ml. Titraton takes approximately 8 minutes per sample, and the repeatability is within plus or minus 1-2 micromoles per kg.

Specifications

Apollo Sci Tech AS-C3 Dissolved Inorganic Carbon (DIC)

A Dissolved Inorganic Carbon (DIC) analyser, for use in aquatic carbon dioxide parameter analysis of coastal waters, sediment pore-waters, and time-series incubation samples. The analyser consists of a solid state infrared CO2 detector, a mass-flow controller, and a digital pump for transferring accurate amounts of reagent and sample. The analyser uses an electronic cooling system to keep the reactor temperature below 3°C, and a Nagion dry tube to reduce the water vapour and keep the analyser drift-free and maintenance-free for longer. It is designed for both land based and shipboard laboratory use.

Specifications

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 and Lever Action bottles have a capacity between 1.7 and 30 L. Reversing thermometers may be attached to a spring-loaded disk that rotates through 180° on bottle closure.

Shelf Sea Biogeochemistry (SSB) dissolved inorganic carbon and total alkalinity from CTD bottles and underway non-toxic seawater supply collected during RRS Discovery cruise DY008

Originator's Protocol for Data Acquisition and Analysis

This dataset contains 118 individual measurements (81 from CTD rosette, 28 from underway) of seawater dissolved inorganic carbon (DIC) and total alkalinity (TA) from the Celtic Sea (50 °N 8 °W). The samples were collected during RRS Discovery cruise DY008 in March-April 2014, as part of the UK Shelf Sea Biogeochemistry research programme.

Samples for dissolved inorganic carbon (DIC) and total alkalinity (TA) were collected from the water samplers via silicone tubing, following established best-practice protocols (Dickson et al., 2007). The sample bottles (250 ml borosilicate glass bottles with ground glass stoppers) were thoroughly rinsed with excess sample directly before filling until overflowing with seawater, taking care not to generate or trap any air bubbles. A 2.5 mL air headspace and 50 µl of saturated mercuric chloride solution were introduced to each bottle before sealing shut with Apiezon L grease and tape. The samples were stored in the dark until analysis.

All measurements of both DIC and TA were calibrated using batches 128, 135 and 138 certified reference material (CRM) obtained from A.G. Dickson (Scripps Institution of Oceanography, USA) (Dickson et al., 2003). DIC was analysed using a DIC Analyzer AS-C3 (Apollo SciTech, USA. The analyser drew a 0.75 or 1 ml subsample from DIC/TA sample bottle for DIC analysis. Subsample was mixed with excess 10% phosphoric acid to convert all bicarbonate and carbonate ions to CO₂. Nitrogen carrier gas was passed through the subsample to carry all CO₂ into LI-COR LI-7000 CO₂/H₂O Analyzer, which measured total CO₂ by infra-red absorption. The process was repeated 5-7 times per sample and the mean result reported. The precision for DIC analysis was 3.2 µmol/kg-seawater. TA was analysed using a Total Alkalinity Titrator AS-ALK2 (Apollo SciTech, USA). The titrator drew a subsample from the DIC/TA sample bottle for TA analysis after the DIC analysis was complete. The subsample was transferred to glass beaker immersed in a water bath at 25 °C with magnetic stirring. Then 0.1M HCl was titrated into subsample until an endpoint pH was reached. pH was monitored by glass electrode, which was regularly calibrated using buffer solutions. The precision of the TA analysis was 2.1 µmol/kg-seawater.

References Cited

Dickson, A.G., Afghan, J.D. and Anderson, G.C., 2003. Reference materials for oceanic CO₂ analysis: a method for the certification of total alkalinity. Mar Chem (80): Issues 2-3, pp 185?197, doi:10.1016/S0304-4203(02)00133-0.

Dickson, A.G., Sabine, C.L. and Christian, J.R., 2007. Guide to best practices for ocean CO₂ measurements. PICES Special Publication 3. pp 191.

BODC Data Processing Procedures

Data were provided in an Excel spreadsheet and archived at BODC. The file contained the water sample data from CTD bottles and the underway non-toxic flow through. Data received were loaded into the BODC database using established BODC data banking procedures. The data were loaded into BODC's database without any changes.

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

Data Quality Report

Bad results resulting from technical issues during analysis have been removed from these results, so there are no recognised issues. These data will undergo a further QC step once all SSB measurements have been completed, so although these results are unlikely to change significantly, they are not necessarily final. (Originator's assessment).

Problem Report

None. (BODC assessment).

Project Information

Shelf Sea Biogeochemistry (SSB) Programme Work Package 1: CaNDyFloSS

Carbon and Nutrient Dynamics and Fluxes over Shelf Systems (CaNDyFloSS) is a £2.76 million component of the Natural Environment Research Council (NERC) Shelf Sea Biogeochemistry (SSB) research programme, running from 2013 to 2017. It is jointly funded by NERC and the Department for Environment, Food and Rural Affairs (DEFRA). The aim of the research is to perform a comprehensive study of the cycling of nutrients and carbon throughout the water column over the whole north-west European shelf. This will allow the fluxes of nutrients and carbon between the shelf and the deep ocean and atmosphere to be quantified, establishing the role of the north-west European continental shelf in the global carbon cycle.

Background

Shelf seas are the primary regions of human marine resource exploitation, including both renewable and fossil fuel energy sources, recreation, trade and food production. They provide 90% of global fish catches which form an important source of food to much of the global population. They also play an important role in the ecosystem services provided by the oceans as a whole, in particular in storing carbon away from the atmosphere.

Physical and biochemical processes in shelf seas influence the removal of CO₂ from the atmosphere and the subsequent storage of carbon in the deep ocean. Biological growth draws carbon out of the water, which is then replaced by carbon in CO₂ from the atmosphere. In the shelf seas this growth is supported by terrestrial and open ocean sources of nutrients, implying intimate roles for both the terrestrial biosphere and the open ocean environment in regulating shelf sea climate services. The oceans can also be a major source or sink for other greenhouse gases, including nitrous oxide (N₂O), with the shallow shelf sea thought to play a key role.

The spatial extent of the submerged continental shelves varies greatly. The NW European shelf sea is one of the largest and hence is likely to play a significant role in marine biogeochemical cycling, alongside providing a useful model for other systems. However, even in this relatively well studied region, there is a lack of detailed understanding of the principal controls on the cycling of carbon and the major nutrient elements, nitrogen, phosphorus and silicon. Consequently it is also difficult to predict how the cycling of these elements and hence the carbon removal they support may be altered by ongoing and potential future global change. This work package aims to address these uncertainties through a comprehensive study of the cycling of the major nutrients and carbon throughout the water column over the NW European shelf sea system.

Further details are available on the SSB website.

Participants

9 different organisations are directly involved in research for SSB Work Package 1. These institutions are

• Centre for Environment, Fisheries and Aquaculture Science (Cefas)
• National Oceanography Centre (NOC)
• Plymouth Marine Laboratory (PML)
• Scottish Association for Marine Science (SAMS) / Scottish Marine Institute (SMI)
• University of Aberdeen
• University of Bangor
• University of East Anglia (UEA)
• University of Liverpool
• University of Southampton

In addition, there are third party institutions carrying out sampling work for SSB Work Package 1, but who are not involved in the programme itself. These are:

• The Agri-Food and Biosciences Institute (AFBI)
• Irish Marine Institute (MI)
• Marine Science Scotland (MSS)

Objectives

Two overarching objectives are defined for this Work Package.

• Objective 1: Estimate the size of the continental shelf carbon pump over the whole north-west European shelf.
  This will consist of two principal activities. (1) Over a 12 month period, observations of air-sea CO₂ fluxes will be made to provide a synoptic estimate of the magnitude of carbon update by the whole shelf system. (2) Concentrations of carbon (C), nitrogen (N), phosphate (P) and silicate (Si) will be estimated in water flowing on and off the shelf. These estimates will be coupled to estimates of flow and dispersion along the shelf edge, through collaboration with the NERC Fluxes across Sloping Topography of the North East Atlantic (FASTNEt) programme to allow an observational estimate of the net off-shelf transport of C, N, P and Si.

• Objective 2: Determine the relative importance of external nutrient sources and internal biogeochemical cycling in maintaining the continental shelf pump.
  Estimates of the flux of nutrients and carbon generated in Objective 1 will be used to determine the estimation of any excess of on-shelf nutrient supply, relative to that of carbon. Work Package 1 will then quantify the processes which govern internal biogeochemical cycling by measuring the uptake ratios of N, P, Si and C into phytoplankton and the element and energy balance of organic matter production by autotrophs. Potential modifications to the relative concentrations and uptake of C, N, P and Si in the thermocline and sediment food webs will also be assessed, as will the relative importance of microbial and zooplankton turnover in controlling C, N, P and Si.

Fieldwork and data collection

Data for Objective 1 will be provided using pCO₂ systems aboard third party vessels and ferry boxes, along with measurements made through the FASTNEt programme and through the Work Package 1 process cruises detailed below. The third party cruises will be undertaken by Cefas, MI, MSS, University of Bangor and AFBI, spanning the shelf seas and shelf-edges around the United Kingdom and the Republic of Ireland.

The Work Package 1 process cruises will provide data for Objective 1 and Objective 2 and are listed in the table below. The study area is the marine shelf (and shelf-edge) of the Celtic Sea. Work will be carried out on board the NERC research vessels RRS Discovery and RRS James Cook. These cruises will focus on the physics and biogeochemistry of the benthic and pelagic zones of the water column, primarily around four main sampling sites in this area.

Activities will include Conductivity Temperature and Depth (CTD) deployments, Acoustic Doppler Current Profilers (ADCP) surveys, moorings and wire-walker deployments, autonomous gliders and submersible surveys, Marine Snow Catcher particulate matter analysis, plankton net hauls and laboratory incubations with sea water samples.

Data Activity or Cruise Information

Data Activity

BODC Sample Metadata Report for DY008_UCCTD_054

Please note:the supplied parameters may not have been sampled from all the bottle firings described in the table above. Cross-match the Sample Reference Number above against the SAMPRFNM value in the data file to identify the relevant metadata.

Related Data Activity activities are detailed in Appendix 1

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:

Appendix 1: DY008_UCCTD_054

Related series for this Data Activity are presented in the table below. Further information can be found by following the appropriate links.

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