Metadata Report for BODC Series Reference Number 2308824

• 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

Data access conditions (generic)

Access to these data is currently restricted and the data may not be released by BODC without obtaining specific permission from the data originator.

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.

Chelsea Technologies Group Aquatracka MKIII fluorometer

The Chelsea Technologies Group Aquatracka MKIII is a logarithmic response fluorometer. Filters are available to enable the instrument to measure chlorophyll, rhodamine, fluorescein and turbidity.

It uses a pulsed (5.5 Hz) xenon light source discharging along two signal paths to eliminate variations in the flashlamp intensity. The reference path measures the intensity of the light source whilst the signal path measures the intensity of the light emitted from the specimen under test. The reference signal and the emitted light signals are then applied to a ratiometric circuit. In this circuit, the ratio of returned signal to reference signal is computed and scaled logarithmically to achieve a wide dynamic range. The logarithmic conversion accuracy is maintained at better than one percent of the reading over the full output range of the instrument.

Two variants of the instrument are available, both manufactured in titanium, capable of operating in depths from shallow water down to 2000 m and 6000 m respectively. The optical characteristics of the instrument in its different detection modes are visible below:

* The wavelengths for the turbidity filters are customer selectable but must be in the range 400 to 700 nm. The same wavelength is used in the excitation path and the emission path.

The instrument measures chlorophyll a, rhodamine and fluorescein with a concentration range of 0.01 µg l^-1 to 100 µg l^-1. The concentration range for turbidity is 0.01 to 100 FTU (other wavelengths are available on request).

The instrument accuracy is ± 0.02 µg l^-1 (or ± 3% of the reading, whichever is greater) for chlorophyll a, rhodamine and fluorescein. The accuracy for turbidity, over a 0 - 10 FTU range, is ± 0.02 FTU (or ± 3% of the reading, whichever is greater).

Further details are available from the Aquatracka MKIII specification sheet.

CTD upcast data at time of bottle firing for JC278

Acquisition description:

Sampling methodology

19 stainless steel CTD (Conductivity, Temperature, Depth) casts were undertaken during the RRS James Cook cruise 278 (JC278), between the 30th of May 2025 to 23rd June 2025, at the Porcupine Abyssal Plain - Sustained Observatory (PAP-SO) site in the North East Atlantic ocean. An NMF (National Marine Facilities) 24-way Stainless Steel CTD frame was used with 20 litre Niskin water samplers. The CTD was deployed on CTD wire storage drum 2, and was operated out of the water bottle annex by the ship’s crew, using the winch belly box. Once over the side, the CTD was lowered to a depth of 10 metres, allowing time for the SBE (Sea-Bird Electronics) 5T pumps to prime. The winch system Active Heave Compensation (ACH) was used throughout JC278 (when below 100 metres) with no issues. The Niskin water samplers were fired to collect samples, and the upcast data was recorded at the time of bottle firing. Dual Sea-Bird SBE 43 dissolved oxygen sensors were used. The primary temperature (Sea-Bird SBE 3plus (SBE 3P)), conductivity (Sea-Bird SBE 4C) and dissolved oxygen (Sea-Bird SBE 43) sensors were fitted to the Sea-Bird SBE 9Plus, with the secondary sensors mounted on the vane. The shallowest cast was CTD001 at 125 metres and the deepest was CTD013 at 4840 metres. Between casts, the whole CTD package was rinsed with fresh water, with particular attention paid to the SBE 32 latch assembly. After each cast, the primary and secondary sensors were flushed three times with Milli-Q. Periodically, the optical sensors were also cleaned with Milli-Q and optic prep wipes.

Analytical methodology

There were no major technical issues with the Stainless Steel CTD suite during JC278. During the first 2 casts, it was noticed the oxygen differences were ranging from 8 – 12 % saturation (Sea-Bird recommends below 4%). Once the oxygen sampling data had been received, the issue was pinpointed to the primary sensor. The sensor was changed and from then onwards saturation was below 1%.

Instrument description

Further information can be found in the JC278 CTD Instrumentation document.

JC278 Cruise report

Further information can be found in the JC278 Cruise report.

BODC Data Processing Procedures

Data received were loaded into the BODC database using established BODC data banking procedures. A parameter mapping table is provided below:

Data Quality Report

28 values of BVSFO650 were below 0 /m/sr and BODC flag 'M' was applied to each occurrence, indicating there may be a problem with the data.

BODC flag 'M' was also applied to data points that were significantly different from the trend of the data, this occurred in parameters DOXYSU01, POPTDR01, BVSFO650 and DOXYSU02.

Project Information

Marine LTSS: AtlantiS (Atlantic Climate and Environment Strategic Science)

Introduction

AtlantiS is a five year (2024 to 2029) programme, funded by the Natural Environment Research Council (NERC).

Scientific Rationale

The global ocean is the largest part of the Earth's climate system and acts as a major buffer to climate changes resulting from human activities. By absorbing 90% of excess heat and nearly a quarter of carbon resulting from anthropogenic greenhouse gas emissions, the ocean has already substantially mitigated climate change in the atmosphere and on land. However, this service has come at a cost to the health and resilience of the ocean and by extension the people who depend on it. Significant damage has been caused to biodiversity and productivity of marine ecosystems, to shelf seas and coastal environments, and to inland areas through extremes of weather. The futures of regional climate and ecological systems depend on the response of the ocean to multiple anthropogenic stressors. Understanding and predicting the response is fundamental for sustainable development and to guide adaptation and mitigation.

The challenge is that the ocean is so large and variable that it cannot be completely and fully observed. Achieving adequate knowledge on all scales requires international coordination of observing and modelling over decades. It requires advancement in technology to expand our ability to observe beyond individual ships. It requires expanding the range of variables measured to include biogeochemistry and ecology. The opportunity now is to lead new capability to combine observations from a widening range of platforms and sensors, next-generation ocean and coupled models, and innovation in digital tools to meet the goal above. A range of national and international reviews have identified priority knowledge gaps related to natural and anthropogenically driven changes in the global ocean and the Atlantic and its shelf seas, and their impacts on marine ecosystems and human society:

• how natural and anthropogenic drivers of basin and decadal changes alter the Atlantic ecosystem, and the consequences for ecosystem functioning and services;
• the importance of ocean-shelf-coast connectivity in shaping ecosystems, biodiversity, natural hazards and impacts on society;
• the implications and feedbacks associated with climate mitigation strategies, and the need for improved assessments and advice to policy makers;
• the sensitivity and timescales of feedbacks that determine the ability of the ocean to continue to mitigate climate change by absorbing excess heat and carbon.

The aim of the AtlantiS programme is to provide evidence, tools and knowledge to support the ambition for healthy, biologically diverse and resilient marine environments, a sustainable blue economy and communities safe from natural hazards. The objectives are to strengthen the capacity of UK marine science to observe, model and predict the ocean through a step change in capability to maximise the value inherent in marine data; to transform the ocean from being data poor to data rich; to provide global syntheses of iconic climate change indicators; to lead an increase in public and government understanding of the role of the ocean in climate; and to communicate actionable knowledge effectively. AtlantiS is the continuation and development of the CLASS programme, enhancing the long-term, large-scale ocean observation systems and the ocean value-chain that contributes to key national and international programmes and priorities.

Data Activity or Cruise Information

Data Activity

BODC Sample Metadata Report for JC278_CTD_JC278_CTD001

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: JC278_CTD_JC278_CTD001

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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