Metadata Report for BODC Series Reference Number 1971856

• 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

RRS Discovery cruise DY034 navigation quality control report

Bathymetry

Swath bathymetry detected depths by up to approx. 600 m greater than GEBCO at the shelf-edge. The ship was situated close to shelf-edge canyons at the time, which were likely detected by the direct measuring swath, whereas the GEBCO dataset contained only interpolated data in this area. (BODC assessment)

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

Kongsberg EM122 12kHz Multibeam Echosounder

The EM122 is designed to perform seabed mapping to full ocean depth with a high resolution, coverage and accuracy. Beam focusing is applied both during reception and transmission. The system has up to 288 beams/432 soundings per swath with pointing angles, which are automatically adjusted according to achievable coverage or operator defined limits.

This model uses both Continuous Wave and Frequency Modulated sweep pulses with pulse compression on reception, in order to increase the maximum useful swath width. The transmit fan is split in several individual sectors, with independent active steering, in order to compensate for the vessel movements.

In multiplying mode, two swaths per ping cycle are generated, with up to 864 soundings. The beam spacing is equidistant or equiangular and the transmit fan is duplicated and transmitted with a small difference in along track tilt, which takes into account depth coverage and vessel speed, to give a constant sounding separation along track. In high density mode, more than one sounding per beam can be produced, such that horizontal resolution is increased and is almost constant over the whole swath.

The EM122 transducers are modular linear arrays in a Mills cross configuration with separate units for transmit and receive. If used to deliver sub-bottom profiling capabilities with a very narrow beamwidth, this system is known as SBP120 Sub-Bottom Profiler.

The specification sheet can be accessed here Kongsberg EM122.

Specifications

EM122 versions

RRS Discovery cruise DY034 navigation instrumentation

Instrumentation

The following scientific navigational and bathymetry systems were fitted.

Trimble Applanix Position and Orientation Systems for Marine Vessels (POSMV)

The Position and Orientation Systems for Marine Vessels (POSMV) is a real time kinematic (RTK) and differential global positioning system (DGPS) receiver for marine navigation. It includes an inertial system that provides platform attitude information. The instrument provides accurate location, heading, velocity, attitude, heave, acceleration and angular rate measurements.

There are three models of Applanix POSMV, the POS MV 320, POS MV Elite and the POS MV WaveMaster. POS MV 320 and POS MV WaveMaster are designed for use with multibeam sonar systems, enabling adherence to IHO (International Hydrographic Survey) standards on sonar swath widths of greater than ± 75 degrees under all dynamic conditions. The POS MV Elite offers true heading accuracy without the need for dual GPS installation and has the highest degree of accuracy in motion measurement for marine applications.

Specifications

POS MV 320

POS MV WaveMaster

POS MV Elite

¹ One Sigma, depending on quality of differential corrections
² Whichever is greater, for periods of 20 seconds or less

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

RRS Discovery cruise DY034 navigation data processing procedures

Originator's Data Processing

Output from the surfmet sensors were initially logged by a designated PC. Some of the sensor's firmware, connection modules and PC software manipulated the output. All the sensors used (including the surfmet sensors) were then registered by the TECHSAS logging system and broadcast to NetCDF, pseudo-TECHSAS ascii and UKORS format in the raw_data area of the level-C logging system. Data used here was extracted from the daily TECHSAS ascii files.

Daily pseudo-TECHSAS ascii files were copied to the local PC where they were reformatted and appended using the following matlab scripts:

• uw_nav - reformatted daily 1 Hz POS MV positional files (#Applanix_GPS_DY1.aplnx) to ascii (DY034_NAV_#_raw.txt).
• uw_swath - reformatted daily 1 Hz swath files (#EM120_DY1.EM1_1) to ascii (DY034_SWATH_#_raw.txt).
• uw_gyro - reformatted daily 1 Hz POS MV gyro files (#-GYRO1_DY1.GYRO1) to ascii (DY034_GYRO1_#_raw.txt).

• uw_appen - appended daily 1 Hz ascii files to master ascii files (DY033_NAV_master_raw.txt, DY033_SWATH_master_raw.txt and DY033_GYRO1_master_raw.txt)

The swath bathymetry was filtered of noise and averaged as follows:

• uw_swclean - filtered the swath bathymetry (DY034_SWATH_master_raw.txt). Output: DY034_SWATH_master_filt.txt.
• uw_swavg - averaged the filtered 1 Hz data (DY034_SWATH_master_filt.txt) over 30 second (DY034_SWATH_master_30secav.txt) and 150 second (DY034_SWATH_master_150secav.txt) intervals.

The swath bathymetry was filtered of noise twice by applying a moving average window of 60 seconds and removing all data outside 2 standard deviations of that average.

Files delivered to BODC

No other source of bathymetry information was sent by the originator.

BODC Data Processing

Data were banked at BODC following standard data banking procedures. The originator's variables were mapped to appropriate BODC parameter codes as follows:

DY034_NAV_master_raw_V2.txt

DY034_GYRO_master_raw.txt

DY034_SWATH_master_30secav.txt

All the reformatted data were visualised using the in-house EDSERPLO software. Suspect data were marked by adding an appropriate quality control flag, missing data by both setting the data to an appropriate value and setting the quality control flag.

Position

A check was run on the position data to identify gaps and improbable values (through the calculation of speed). Four gaps were identified. As the gaps were quite small (less than two minutes) interpolation was carried out following standard procedures. A improbable speed was also identified and after visual inspection, the suspect data point was removed and interpolation was applied. No further gaps or speed fails were identified.

Ship's velocities

Ship's eastward and northward velocities were calculated from the main latitude and longitude channels following standard procedures. Suspect flags were automatically applied to all instances where interpolated positions were used.

Distance Run

Distance run was calculated from the main latitude and longitude channels, starting from the beginning of the file.

Project Information

Shelf Sea Biogeochemistry (SSB) Programme

Shelf Sea Biogeochemistry (SSB) is a £10.5 million, six-year (2011-2017) research programme, jointly funded by the Natural Environment Research Council (NERC) and the Department for Environment, Food and Rural Affairs (DEFRA). The aim of the research is to reduce the uncertainty in our understanding of nutrient and carbon cycling within the shelf seas, and of their role in global biogeochemical cycles. SSB will also provide effective policy advice and make a significant contribution to the Living with Environmental Change programme.

Background

The Shelf Sea Biogeochemistry research programme directly relates to the delivery of the NERC Earth system science theme and aims to provide evidence that supports a number of marine policy areas and statutory requirements, such as the Marine Strategy Framework Directive and Marine and Climate Acts.

The shelf seas are highly productive compared to the open ocean, a productivity that underpins more than 90 per cent of global fisheries. Their importance to society extends beyond food production to include issues of biodiversity, carbon cycling and storage, waste disposal, nutrient cycling, recreation and renewable energy resources.

The shelf seas have been estimated to be the most valuable biome on Earth, but they are under considerable stress, as a result of anthropogenic nutrient loading, overfishing, habitat disturbance, climate change and other impacts.

However, even within the relatively well-studied European shelf seas, fundamental biogeochemical processes are poorly understood. For example: the role of shelf seas in carbon storage; in the global cycles of key nutrients (nitrogen, phosphorus, silicon and iron); and in determining primary and secondary production, and thereby underpinning the future delivery of many other ecosystem services.

Improved knowledge of such factors is not only required by marine policymakers; it also has the potential to increase the quality and cost-effectiveness of management decisions at the local, national and international levels under conditions of climate change.

The Shelf Sea Biogeochemistry research programme will take a holistic approach to the cycling of nutrients and carbon and the controls on primary and secondary production in UK and European shelf seas, to increase understanding of these processes and their role in wider biogeochemical cycles. It will thereby significantly improve predictive marine biogeochemical and ecosystem models over a range of scales.

The scope of the programme includes exchanges with the open ocean (transport on and off the shelf to a depth of around 500m), together with cycling, storage and release processes on the shelf slope, and air-sea exchange of greenhouse gases (carbon dioxide and nitrous oxide).

Further details are available on the SSB website.

Participants

15 different organisations are directly involved in research for SSB. These institutions are

• Centre for Environment, Fisheries and Aquaculture Science (Cefas)
• Meteorological Office
• 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 Edinburgh
• University of Essex
• University of Liverpool
• University of Oxford
• Plymouth University
• University of Portsmouth
• University of Southampton

In addition, there are third party institutions carrying out sampling work for SSB, 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)

Research details

Overall, five Work Packages have been funded by the SSB programme. These are described in brief below:

• Work Package 1: Carbon and Nutrient Dynamics and Fluxes over Shelf Systems (CaNDyFloSS).
  This work package aims 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.

• Work Package 2: Biogeochemistry, macronutrient and carbon cycling in the benthic layer.
  This work package aims are to map the sensitivity and status of seabed habitats, based on physical conditions, ecological community structure and the size and dynamics of the nitrogen and carbon pools found there. This information will be used, in conjunction with some laboratory-based work, to generate an understanding of the potential impacts on the benthic community as a result of changing environmental conditions, such as rising CO₂ levels.

• Work Package 3: The supply of iron from shelf sediments to the ocean.
  The research for this work package addresses the question of how currents, tides, weather and marine chemistry allow new iron to be transported away from the shallow shelf waters around the United Kingdom (UK), to the nearby open ocean. This will ultimately allow an improved understanding of how the transport of iron in shelf waters and shelf sediments influences phytoplankton growth in open oceans. This in turn improves the understanding of carbon dioxide uptake by phytoplankton.

• Work Package 4: Integrative modelling for Shelf Seas Biogeochemistry.
  The aim of this work package is the development of a new shelf seas biogeochemical model system, coupled to a state of the art physical model, that is capable of predicting regional impacts of environmental change of timescales from days to decades. It is envisaged that the combination of predictive tools and new knowledge developed in this work package will underpin development and implementation of marine policy and marine forecasting systems.

• Work Package 5: Data synthesis and management of marine and coastal carbon (DSMMAC).
  This work package is funded by Defra and is also known by the name 'Blue Carbon'. The aim is to provide a process-based, quantitative assessment of the role of UK coastal waters and shelf seas in carbon storage and release, using existing data and understanding, and also emerging results from SSB fieldwork, experiments and modelling. Particular emphasis will be given to processes that may be influenced by human activities, and hence the opportunity for management interventions to enhance carbon sequestration.

Fieldwork and data collection

The campaign consists of the core cruises in the table below, to the marine shelf (and shelf-edge) of the Celtic Sea 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.

Core cruises will be supplemented by partner cruises led by Cefas, MI, MSS, Bangor University and AFBI, spanning the shelf seas and shelf-edges around United Kingdom and Republic of Ireland.

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

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

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: