Metadata Report for BODC Series Reference Number 1655564

• 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

Public domain data

These data have no specific confidentiality restrictions for users. However, users must acknowledge data sources as it is not ethical to publish data without proper attribution. Any publication or other output resulting from usage of the data should include an acknowledgment.

The recommended acknowledgment is

"This study uses data from the data source/organisation/programme, provided by the British Oceanographic Data Centre and funded by the funding body."

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 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.

RV Prince Madog cruise PD21_11 chlorophyll and phaeopigment series measured by Cefas

Originator's data processing

Samples for chlorophyll and phaeopigments were collected by the Centre for Environment, Fisheries and Aquaculture Science (Cefas) on a Proudman Oceanographic Laboratory (POL) Oceans 2025 SO11 cruise (number 78) in Liverpool Bay. The cruise ran from 25 to 28 July 2011 on the RV Prince Madog. A total of 42 near-surface samples of chlorophyll and phaeopigments were taken from 38 of the 94 CTD casts performed on this cruise. Triplicate chlorophyll and phaeopigment samples were taken during cast001 and cast002.

A volume of 250 ml is passed through a Whatman GF/F filter under low vacuum for each sample collected. The filter paper is then folded in half, loosely wrapped in aluminium foil and placed in a plastic bag. Samples are stored in this way in a box containing desiccant at -18 °C until analysis. Filters are extracted using 8 ml 90% acetone and measured fluorometrically according to Tett (1987) for chlorophyll-a and phaeopigments. Cefas use a Turner 10 AU field fluorometer, which has been calibrated using a pure solution of chlorophyll-a.

Processing undertaken by BODC

The data were supplied to BODC as an Excel spreadsheet. This was converted to an ASCII format file for loading into the BODC archive. The variables supplied by the Data Originator were mapped to BODC parameter vocabularies as follows:

The data and metadata fields were checked and then loaded into the database under the Oracle Relational Database Management System by matching the sample's date, time and depth with the information already held in the database for this cruise. The cruise report indicates that near-surface Cefas samples were collected using the water bottles located at rosette positions 11 and 12. The CTD log sheets for this cruise indicate that rosette position 11 was used exclusively in every cast except cast001 and cast002. For these casts, bottles were fired at both rosette positions.

There is no information which links the chlorophyll and phaeopigment samples collected during cast001 and cast002 to a specific rosette position. Therefore, BODC have arbitrarily assigned the pigment samples which were collected during these casts a rosette position of 11. Triplicate samples were taken by CEFAS during cast001 and cast002. The mean and standard deviation of these samples were calculated by BODC and stored in the database. The individual sample values from these casts have been archived and are available on request. For single samples, the data were loaded without further modification.

References

Tett , P. 1987. Plankton. In: J.M. Baker, J.W. Wolff, eds., Biological surveys of estuaries and coasts. Cambridge University Press, Cambridge, pp 280-341.

Project Information

Oceans 2025 Theme 10, Sustained Observation Activity 11: Liverpool Bay and Irish Sea Coastal Observatory

Sustained, systematic observations of the ocean and continental shelf seas at appropriate time and space scales allied to numerical models are key to understanding and prediction. In shelf seas these observations address issues as fundamental as 'what is the capacity of shelf seas to absorb change?' encompassing the impacts of climate change, biological productivity and diversity, sustainable management, pollution and public health, safety at sea and extreme events. Advancing understanding of coastal processes to use and manage these resources better is challenging; important controlling processes occur over a broad range of spatial and temporal scales which cannot be simultaneously studied solely with satellite or ship-based platforms.

Considerable effort has been spent by the Proudman Oceangraphic Laboratory (POL) in the years 2001 - 2006 in setting up an integrated observational and now-cast modelling system in Liverpool Bay (see Figure), with the recent POL review stating the observatory was seen as a leader in its field and a unique 'selling' point of the laboratory. Cost benefit analysis (IACMST, 2004) shows that benefits really start to accrue after 10 years. In 2007 - 2012 exploitation of (i) the time series being acquired, (ii) the model-data synthesis and (iii) the increasingly available quantities of real-time data (e.g. river flows) can be carried out through Sustained Observation Activity (SO) 11, to provide an integrated assessment and short term forecasts of the coastal ocean state.

Overall Aims and Purpose of SO 11

• To continue and enlarge the scope of the existing coastal observatory in Liverpool Bay to routinely monitor the northern Irish Sea
• To develop the synthesis of measurements and models in the coastal ocean to optimize measurement arrays and forecast products. Driving forward shelf seas' operational oceanography with the direct objective of improving the national forecasting capability, expressed through links to the National Centre for Ocean Forecasting (NCOF)
• To exploit the long time-series of observations and model outputs to: a) identify the roles of climate and anthropogenic inputs on the coastal ocean's physical and biological functioning (including impacts of nutrient discharges, offshore renewable energy installations and fishing activity) taking into consideration the importance of events versus mean storms / waves, river discharge / variable salinity stratification / horizontal gradients; b) predict the impacts of climate change scenarios; and c) provide new insights to Irish Sea dynamics for variables either with seasonal cycles and interannual variability, or which show weak or no seasonal cycles
• To provide and maintain a 'laboratory' within which a variety of observational and model experiments can be undertaken (Oceans 2025 Themes 3, 6, 8, 9), including capture of extreme events
• Demonstrate the value of an integrated approach in assessment and forecasting
• Demonstrate the coastal observatory as a tool for marine management strategies through collaboration with the Environment Agency (EA), Department for Environment, Food and Rural Affairs (DEFRA), Joint Nature Conservation Commmittee (JNCC), English Nature (EN), Department of Agriculture and Rural Development (DARD), and Local Authorities, providing management information pertinent to policy (e.g. Water Framework Directive)

Measurement and Modelling Activities

• East Mooring Site: Bottom frame with full suite of physical measurements (high frequency Acoustic Doppler Current Profiler (ADCP), conductivity, temperature, turbidity and fluorescence), a Centre for Environment, Fisheries and Aquaculture Science (CEFAS) directional wavebuoy, and a CEFAS Smartbuoy collecting surface properties including salinity, temperature, turbidity, nutrients, irradiance and chlorophyll. All transmit data in real-time via Orbcomm. The Smartbuoy also collects daily water samples.
• West Mooring Site: Bottom frame with full suite of physical measurements (high frequency ADCP, conductivity, temperature, turbidity and fluorescence), CEFAS Smartbuoy.
• Spatial Survey: Four - six week intervals (determined by biofouling of optical sensors). Spatial surveys comprise of vertical profiles of CTD, suspended particulate material (SPM), some bed sediment sampling and surface and bed nutrients, phytoplankton, zooplankton.
• Ferry: The Birkenhead - Belfast ferry samples near surface (5 m depth) temperature, salinity, turbidity, chlorophyll, with data transmitted by Orbcomm. The route is scientifically varied passing through six completely different hydrodynamic regions, which significantly impact on their ecological function.
• Tide gauges: Real-time data are obtained from tide gauges operated by Mersey Docks and Harbour Company (MDHC) and the UK tide gauge network.
• Satellite imagery: Weekly composite satellite data, Advanced Very High Resolution Radiometer (AVHRR) sea surface temperature (SST) and ocean colour (chlorophyll and suspended sediment), are provided by the Remote Sensing Data Analysis Service (RSDAS) based at Plymouth Marine Laboratory (PML).
• HF radar: A phased array HF radar system (a 12-16MHz WERA HF radar) measuring surface currents and waves with maximum range 75km at a resolution of 4km for sea surface currents and for 2-D wave spectra.
• Meteorology station: With web camera, located on Hilbre Island at the mouth of the Dee Estuary
• Operational models: The Coastal Observatory uses Proudman Oceanographic Laboratory Coastal Ocean Modelling System (POLCOMS), which is part of Oceans 2025 Theme 9.

More detailed information on this Work Package is available at pages 32 - 35 of the official Oceans 2025 Theme 10 document: Oceans 2025 Theme 10

Weblink: http://www.oceans2025.org/

References:

IACMST., 2004. The Economics of Sustained Marine Measurements. IACMST Information Document, N0.11, Southampton: IACMST, 96 pp

Data Activity or Cruise Information

Data Activity

BODC Sample Metadata Report for PD21_11_CTD_cast030

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: PD21_11_CTD_cast030

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