Status: Special Area of Conservation (SAC)
The Braemar pockmarks are a series of crater-like depressions situated in the seabed in the northern North Sea, approximately 240 km east of the Orkney Islands.
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Site
Located approximately 240 km east of the Orkney Islands, the Braemar pockmarks are a series of crater-like depressions in the seabed in the northern North Sea.
The pockmarks within the site are shallow, ovoid, seabed depressions, several metres across, which were created by the expulsion of fluids into the water column. Forty-eight pockmarks have been identified within the Braemar Pockmarks SAC boundary; all of which are greater than 20 m in diameter, the largest being 200 m in diameter. Six of the pockmarks have verified examples of the Annex I habitat Submarine structures made by leaking gases – a listed habitat under Annex I of the EC Habitats Directive. These carbonate blocks, pavements slabs and smaller fragments of methane-derived authigenic carbonate (MDAC) have been deposited at the base of the pockmarks through a process of precipitation during the anaerobic oxidation of methane (AOM) by a unique community of microbial organisms. The habitat may host specialist organisms, for example those with chemosynthetic symbionts, whilst the carbonate structures provide a habitat for marine fauna usually associated with rocky reef. Larger blocks of carbonate can also provide shelter for fish species such as wolf-fish.
More detailed site information can be found in the Summary section below.
Map displaying the Braemar Pockmarks MPA boundary and associated protected feature data. Visit JNCC's MPA Mapper to further view and explore data for this MPA.
Legislation
Legislation behind the designation: EU Habitats Directive 1992, transposed into UK law by the The Conservation of Offshore Marine Habitats and Species Regulations 2017 (as amended).
Protected Features
| Feature | Feature Type |
| 1180 Submarine structures made by leaking gases | Annex I Habitat |
Specific information on the conservation objectives relating to this site is provided in the Conservation Advice section.
The acquisition of new data may result in updates to our knowledge on feature presence and extent within this site. The most up-to-date information is reflected on the map on this page and in JNCC’s MPA Mapper, and the evidence underpinning this can be viewed in the Monitoring and Evidence section.
Site Timeline
The diagram below is a summary of the key milestones involved in the selection and designation of Braemar Pockmarks SAC. More detail can be found in the Relevant Documentation section.
Relevant Documentation
The documents referred to below and any other historical documents relating to Braemar Pockmarks SAC were produced during the selection and designation process and therefore may be out of date. This Site Information Centre is the most up-to-date source of information for this MPA, and will reflect any additional information gathered since these documents were produced. Information about the SAC site selection process is available on JNCC's SAC webpages.
Amended boundary 2017:
- Standard Data Form – Provides details about the SAC/SCI and the designated features.
- SAC Selection Assessment Document – Overview of the SAC/SCI, designated features and rationale for site selection.
- Boundary Amendment Document – Information about the boundary amendment
- Post-consultation Report & Impact Assessment – Overview of the consultation outcomes, and an assessment of the environmental, social and economic costs and benefits of the designation.
- Management Options Paper – Considers the management options for achieving the conservation objective for the protected feature in the MPA.
- JNCC's formal conservation advice for this site is available in the Conservation Advice section below.
Original boundary: An amendment to the site boundary for Braemar Pockmarks was consulted on in 2017 and approved and submitted to the European Commission in September 2018. More information, and the original documents for the site, can be found in the consultation archive (available on The National Archives website).
These resources are available on JNCC's Resource Hub.
Summary
Last updated: October 2018
Information for this site summary was adapted from the SAC Selection Assessment Document and incorporates any further information gathered since this document was produced.
Site overview
The Braemar pockmarks are a series of crater-like depressions on the sea floor, six of which contain verified records of the Annex I habitat Submarine structures made by leaking gases. In this location, large blocks, pavements slabs and smaller fragments of methane-derived authigenic carbonate (MDAC) have been deposited through a process of precipitation during the anaerobic oxidation of methane (AOM) by a unique community of microbial organisms. This AOM activity at the sulphate-methane interface (SMI) beneath the seabed results in the presence of hydrogen sulphide in the sediments. The sulphide-rich sediments may host specialist organisms, for example those with chemosynthetic symbionts, whilst the carbonate structures provide a habitat for marine fauna usually associated with rocky reef. Larger blocks of carbonate can also provide shelter for fish species such as wolf-fish.
The name of the site originates from its proximity to the Braemar oil field in the northern North Sea, approximately 240 km east of the Orkney Islands. The site is situated to the north of the Witch Ground Basin at a water depth of approximately 120 m. The pockmarks within the site are shallow, ovoid, seabed depressions, several metres across, which were created by the expulsion of fluids into the water column. It is in the base of these pockmarks where MDAC is formed beneath the seabed. Most of the pockmarks in the Witch Ground Basin occur in very soft muds, however the pockmarks in Braemar Pockmarks SAC occur in firmer, slightly coarser sediments.
Forty-eight pockmarks have been identified within the Braemar Pockmarks SAC boundary; all of which are greater than 20 m in diameter, the largest being 200 m in diameter. Six of the pockmarks have verified examples of the Annex I habitat Submarine structures made by leaking gases, with a further 14 showing strong acoustic reflectance. The high backscatter may be indicative of hard carbonate structures so are considered as potential feature records associated with pockmarks. Both verified and potential occurrences of the habitat are considered to represent the known extent of the feature within the site.
Braemar Pockmarks SAC is one of three sites identified for protection of Annex I Submarine structures made by leaking gases in the UK. There is one other SAC in the Northern North Sea with Submarine structures made by leaking gases as a qualifying interest feature of the site. Scanner Pockmark SAC is situated to the south-west of Braemar Pockmarks. There is also a site in the Irish Sea – Croker Carbonate Slabs SAC.
Further detail on the evidence for this SAC can be found in the Monitoring and Evidence section.
Site location: Co-ordinates for this SAC can be found in the Standard Data Form listed in the Relevant Documentation section.
Site area: 11.43 km2
Site depth range: Depth at the site is relatively even and ranges from 120 m to 124 m below sea-level.
Charting Progress 2 Biogeographic Region: Northern North Sea.
Site Boundary Description: The boundary for the Braemar Pockmarks is a simple polygon enclosing the minimum area necessary to ensure protection of the Annex I habitat. Co-ordinate points have been positioned as close to the edge of the interest feature as possible, rather than being located at the nearest whole degree or minute point. As bottom trawling is a significant threat to the interest feature, the proposed boundary includes a margin to ensure its protection.
Monitoring and Evidence
Last updated: November 2023
There are a range of data to underpin this SAC. The full overview of the data used to support site identification, along with information on confidence in feature presence and extent, is available in the Braemar Pockmarks MPA SAC Selection Assessment Document. All data that can be made publicly available are displayed on JNCC's MPA Mapper.
Some of the data for this SAC have been collected through JNCC-funded or collaborative surveys and some through other means. Data from these surveys provide direct evidence confirming the presence of the protected features within the site.
Survey and data gathering
- Cruise report for the offshore seabed survey of Braemar Pockmarks SAC and Scanner Pockmark SAC (2017) – This cruise report summarises operations and initial observations made onboard the RV Cefas Endeavour during the cruise CEND19x/12 on behalf of JNCC. The survey took place between 17 November and 1 December 2012. The aim was to gather additional evidence to support the development of fisheries management measures and develop a baseline for future site monitoring.
Data analysis reports
Analyses of data gathered as part of the survey listed above, as well as other relevant data analysis products, are available via the following reports:
- Offshore seabed survey of Braemar Pockmarks and Scanner Pockmark (2017) – Presents results from the analyses of the data gathered during the seabed survey of the Braemar Pockmarks and Scanner Pockmark in 2012 (cruise CEND19x/12). The report describes the presence, location and extent of the pockmarks, along with detail relating to the presence and location of any associated Methane Derived Authigenic Carbonate (MDAC) structures where they were observed to occur based on video, stills and laboratory sample analysis.
- Geological investigation of pockmarks in the Braemar Pockmarks SCI and surrounding area (2015) – Describes the findings of a desk study carried out by British Geological Survey (BGS) for JNCC covering the Braemar Pockmarks area. The main dataset for this study in the JNCC research cruise at the end of 2012 (cruise CEND19x/12). The report confirmed there is strong evidence of active gas seepage within Braemar SAC, including the presence of methane derived authigenic carbonate (MDAC), as well as gas bubbles in the water column. MDAC was recorded 11 times within six different pockmarks, (five within the site boundary, the other just 500 m outside) during the 2012 survey. Some pockmarks show change in their morphology reflecting slope failure, supporting the interpretation that these pockmarks are sites of active processes. Strong acoustic reflections shown in multibeam backscatter data suggest that harder substrate may be present in other areas of the site too. These require further investigation (such as through visual observation or seabed sampling) to determine whether they are examples of carbonate blocks, shell fragments or a change in sediment particle size.
- Petrography and stableisotope study of methane – derived authigenic carbonate (MDAC) from the Braemar Pockmark Area, North Sea (2013) – The British Geological Survey was commissioned by CEFAS to undertake petrographic and stable isotope investigation of samples of carbonate-cemented sediment recovered from the JNCC/CEFAS 2012 survey. Reporting is underway and will be made available in due course.
Additional relevant literature
References for further supporting scientific literature consulted during the identification of this site can be found in the Selection Assessment Document. Please be aware that although these sources contain information in relation to this MPA, they do not necessarily represent the views of JNCC.
- Judd, A.G. and Hovland, M. (2007). Seabed fluid flow: the impact on geology, biology and the marine environment. Cambridge: Cambridge University Press. – Describes seabed fluid flow features and processes, and demonstrates their importance to human activities and natural environments.
- Biddick, K., Spink, J. and Nichols, P. (2006). Harding Area Gas Project. Seabed Habitat Assessment Survey, Environmental Habitat Assessment Report, Volume 3. Report for BP Exploration Operating Company Ltd by Gardline Environmental Ltd – Details a habitat assessment survey conducted by Gardline Environmental on behalf of BP, for two proposed new pipeline routes within the vicinity of Braemar oil field.
- Hartley, J.P. (2005), Seabed investigation of Pockmark Features in UKCS Block 16/3, Report to JNCC – Details several pockmarks containing carbonate cemented rocks and chemosynthetic biota discovered in the central North Sea in the vicinity of the Braemar field (UKCS Block 16/3). The pockmarks are of note as they occur outside areas previously recognised as containing pockmarks.
- Berry, T. and Stewart, E. (2002). Braemar Pipeline Route Surveys. Report for Marathon Oil U.K Ltd. – A geophysical and geotechnical sampling, and an environmental baseline survey along three proposed pipeline routes in UKCS block 16/3, 16/7 and 16/8, carried out by Fugro survey limited on the instructions of Marathon Oil U.K. Ltd.
- Marathon Oil UK Ltd (2002). Braemar Field Development Environmental Statement. – This Environmental Statement presents the findings of the Environmental Assessment conducted by Marathon for the proposed Braemar field development.
- Dando, P.R. (2001) A review of pockmarks in the UK part of the North Sea, with particular respect to their biology. Technical report produced for Strategic Environmental Assessment, SEA2. Department of Trade and Industry Technical Report No. TR_001. – The report describes pockmarks in the UK North Sea, and their biology. Although this paper doesn’t refer to Braemar Pockmarks specifically there is good detail on species found within Pockmark habitats.
- Judd, A.G. (2001). Pockmarks in the UK Sector of the North Sea. Technical report produced for Strategic Environmental Assessment, SEA2. Department of Trade and Industry Report No. TR_002. – The report describes pockmarks, their formation and character, and their occurrence in the North Sea (with specific reference to the SEA2 areas). The report reviewed current understanding of pockmarks in the UK North Sea, with specific reference to the methane-derived authigenic carbonate (MDAC).
- Dando, P.R., Austen, M.C., Burke, R.J., Kendall, M.A., Kennicutt, M.C., Judd, A.G., Moore, D.C., O'Hara, S.C.M., Schmaljohann, R. and Southward, A.J. (1991) Ecology of a North Sea Pockmark with an active methane seep. Marine Ecology Progress Series, 70: 49–63. – Survey of a large pockmark in the Fladen ground area of the North Sea. Data from echo-sounders and sediment grabs reveals more about the ecology within the pockmark.
- Hovland, M. and Judd, A.G. (1988). Seabed Pockmarks and Seepages: Impact on geology, biology and the marine environment. London: Graham and Trotman. – This report describes the ecology of seabed pockmarks and seepages and the implications and consequences of these features. Two chapters focus on examples in the North Sea, but other examples from around the world are also described. Features associated with submarine seepages and mineral precipitation is also explored in the report.
Knowledge gaps
As part of the UK Marine Monitoring and Assessment Strategy (UKMMAS), JNCC led the development of a UK Marine Biodiversity Monitoring Strategy, working with partners across the UK monitoring community. The Strategy spans UK territorial and offshore waters, focusing on biodiversity in the wider environment and within Marine Protected Areas. Its aim is to implement efficient, integrated monitoring of marine biodiversity to provide the evidence needed for all the UK's policy drivers.
The Marine Directorate of Scottish Government, in partnership with JNCC and NatureScot, developed a Scottish Marine Protected Area (MPA) monitoring strategy. The Strategy spans Scottish territorial and offshore waters, focusing on biodiversity within Marine Protected Areas. The Strategy is supported by a series of annexes which provide more detail on monitoring methods, collaborative working, current monitoring and a two year forward look for MPA monitoring in Scottish waters.
The evidence collected during MPA monitoring surveys is used in combination with other available evidence to:
- Enable assessment of condition of the features within sites;
- Contribute to the assessment of the degree to which management measures are effective in achieving the conservation objectives for the protected features;
- Support the identification of priorities for future protection and/or management; and,
- Enable Government to fulfil its national and international assessment and reporting commitments in relation to MPAs and help identify where further action may be required.
More detail on offshore MPA monitoring can be found on the Offshore MPA monitoring webpage. A list of monitoring surveys and relevant reports can be found on the MPA monitoring survey reports webpage.
If you are aware of any additional information not referred to in the Relevant Documentation section or listed above, please contact us.
Conservation Advice
Last updated: February 2018
Updated formal conservation advice is now available for this MPA. Further information on the approach used to develop this advice is available on our Conservation Advice webpages along with a Glossary of Terms used in JNCC's conservation advice and a short video explaining how to use the conservation advice packages.
You must refer to this advice if you:
- undertake a Habitats Regulation Assessment (HRA) for a plan or project that could impact the site;
- provide information for a HRA;
- respond to specific measures to support delivery of the conservation objectives for the site; and
- consider the need to put new or additional management measures in place.
You may also find it useful to refer to this advice if you:
- Carry out any other activity that could impact the site.
We will engage with stakeholders to identify any lessons which JNCC can learn from customers who have used the advice, with a view to continuing to ensure it is fit-for-purpose.
The following table provides an overview of the components of the conservation advice, and provides hyperlinks to each of the products for this MPA. These elements together form JNCC’s formal conservation advice for this site and should be read in conjunction with each other. This updated advice replaces the previous Regulation 18 package for the site. This advice reflects the most up-to-date evidence held by JNCC (correct as of February 2018).
| Document | Overview |
|---|---|
| Background Information | Explains the purpose of the advice and when it must be referred to. |
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The conservation objectives set out the broad ecological aims for the site. JNCC provides supplementary advice in the SACO which is essential reading to support interpretation of these conservation objectives. It provides further detail and site-specific information for each feature within the site including which of the attributes need to be conserved and which ones recovered. You can use these documents to assess the impacts of your planned activity on the important attributes of the site. Please note our current understanding of whether the available evidence indicates that each attribute needs to be recovered or maintained is not provided here. However, links to available evidence for the site are provided and should you require further site-specific information for the site, please contact us. |
| Conservation Advice Statements |
These statements provide a summary of the Supplementary Advice on the Conservation Objectives (SACO).
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| Advice on Operations |
Provides information on the activities capable of affecting site integrity and therefore achievement of the site’s conservation objectives. This is a starting point for determining potential management requirements. It does not take into account the intensity, frequency or cumulative impacts from activities taking place. It is simply to advise you of the possible adverse impacts that your activity can have on a MPA’s features. Use the advice on operations to determine those pressures your activity causes that could harm the habitat and/or species features of the site. |
These resources are available on JNCC's Resource Hub.
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