© OpenStreetMap contributors
Holden's Reef is a small (approximately 40 m diameter), roughly circular reef situated in the northern sector of Cardigan Bay. It is unusual in being formed as a result of a chemical reaction between seawater and the escape of natural gas from the seabed, a phenomenon generally found in much deeper waters. Holden's Reef is one of an assemblage of methanogen-precipitated calcium carbonate reefs and was the first of the group to be discovered. This dataset contains the results of a programme of monitoring established to study fish populations and reef extent. It also includes data from an in-house survey carried out at Holden's Reef in 2003, initiated following the reef's discovery, and Marine Nature Conservation Review (MNCR) phase 2 surveys carried out in 2005 of "Little" and "Big" Reef. Holden's Reef is monitored for fish abundance and diversity extent and rugosity (the link between rugosity and fish abundance has been seen in several studies). This will contribute to condition assessment of the reef feature in the Pen Llyn a'r Sarnau Special Area of Conservation (SAC). Holden's Reef is situated more than 10 km off shore north west of Barmouth and is approximately 40 m in diameter.
Natural Resources Wales (NRW)
There are no access restrictions to this data. NRW may release, publish or disseminate it freely.
Other details | ||
Internal code | Internally assigned metadata identifier | 1897 |
Title | The title is used to provide a brief and precise description of the dataset such as 'Date', 'Originating organisation/programme', 'Location' and 'Type of survey'. All acronyms and abbreviations should be reproduced in full. | Monitoring of Carbonate Reef Extent and Fish Population at Holden's Reef (2003 - 2010) |
Alternative title | The purpose of alternative title is to record any additional names by which the dataset may be known. | Fish abundance and diversity at Holden's Reef, Carbonate reef extent and rugosity, Holden's Reef, Monitro poblogaeth y pysgod a maint y riff carbonad yn Riff Holden, 2005 CCW/Pelagial/Sea-Scope Holden's Reef, Pen Llyn a'r Sarnau sublittoral survey MRCCW3010000000D, 2003 CCW Holden's Reef initial survey MRCCW30000000030 |
File Identifier | The File Identifier is a code, preferably a GUID, that is globally unique and remains with the same metadata record even if the record is edited or transferred between portals or tools. | 4f4c4942-4343-5764-6473-313130393236 |
Resource Identifier | This is the code assigned by the data owner. | 110926 |
Resource type | The resource type will likely be a dataset but could also be a series (collection of datasets with a common specification) or a service. | dataset |
Start date | This describes the date the resource starts. This may only be the year if month and day are not known | 2004-05-18 |
End date | This describes the date the resource ends. This may only be the year if month and day are not known | 2010-12-31 |
Vertical extent (min) | A positive or negative decimal number, for example, the shallowest depth recorded if subtidal, or, if intertidal, the lowest point recorded. | -6.2 |
Vertical extent (max) | A positive or negative decimal number, for example, the deepest depth recorded if subtidal, or, if intertidal, the highest point recorded. | -9.5 |
Vertical extent reference | This descibes the vertical coordinate reference system as referred to in the EPSG register of geodetic parameters. (epsg-registry.org) | urn:ogc:def:crs:EPSG:: |
Spatial resolution | This describes the spatial resolution of the dataset or the spatial limitations of the service. | inapplicable |
Frequency of updates | This describes the frequency with which the resource is modified or updated i.e. a monitoring programme that samples once per year has a frequency that is described as 'annually'. | annually |
Abstract | The abstract provides a clear and brief statement of the content of the resource. | Holden's Reef is a small (approximately 40 m diameter), roughly circular reef situated in the northern sector of Cardigan Bay. It is unusual in being formed as a result of a chemical reaction between seawater and the escape of natural gas from the seabed, a phenomenon generally found in much deeper waters. Holden's Reef is one of an assemblage of methanogen-precipitated calcium carbonate reefs and was the first of the group to be discovered. This dataset contains the results of a programme of monitoring established to study fish populations and reef extent. It also includes data from an in-house survey carried out at Holden's Reef in 2003, initiated following the reef's discovery, and Marine Nature Conservation Review (MNCR) phase 2 surveys carried out in 2005 of "Little" and "Big" Reef. Holden's Reef is monitored for fish abundance and diversity extent and rugosity (the link between rugosity and fish abundance has been seen in several studies). This will contribute to condition assessment of the reef feature in the Pen Llyn a'r Sarnau Special Area of Conservation (SAC). Holden's Reef is situated more than 10 km off shore north west of Barmouth and is approximately 40 m in diameter. |
Lineage | Lineage includes the background information, history of the sources of data, data quality statements and methods. | A site marker (a single road pin) has been established at the centre of the reef in its shallowest part. An additional marker is located due north from the centre at the edge of the reef. The extent of the reef is measured by divers who swim along a bearing from the central marker to the edge of the reef and the distance recorded. The distance from the centre to the edge of the reef is measured at 12 bearings 30 degrees apart. The rugosity of the reef is measured by splitting the reef into an inner and outer zone radiating from the central marker. The distance between the centre and zone boundary is measured using a taut tape measure. This distance is then repeated allowing the tape measure to rest along the contours if the reef. The rugosity is determine d to be the ratio between the two measurements. Fish abundance and diversity is measured by a pair of divers undertaking 3 consecutive timed counts of 5 minute duration. These counts take place in up to 4 zones that represent different topography and depths on the reef. To aid recording slates are pre-marked with species likely to be observed. |
Additional information | This describes relevant references to the data e.g. reports, articles, websites plus other useful information not captured elsewhere. | Detailed methodologies in use at Holden's Reef can be found in Marine Monitoring Report 25b (standard operating procedures 11 12 and 13) |
Related keywords | ||
Keyword | General subject area(s) associated with the resource, uses multiple controlled vocabularies | Habitats and biotopes |
General subject area(s) associated with the resource, uses multiple controlled vocabularies | Species distribution | |
General subject area(s) associated with the resource, uses multiple controlled vocabularies | Fish abundance in water bodies | |
General subject area(s) associated with the resource, uses multiple controlled vocabularies | Fish taxonomy-related counts | |
General subject area(s) associated with the resource, uses multiple controlled vocabularies | Habitat characterisation | |
General subject area(s) associated with the resource, uses multiple controlled vocabularies | Habitat extent | |
General subject area(s) associated with the resource, uses multiple controlled vocabularies | Marine Environmental Data and Information Network | |
Geographical coverage | ||
North | The northern-most limit of the data resource in decimal degrees | 52.741304 |
East | The eastern-most limit of the data resource in decimal degrees | -4.129506 |
South | The southern-most limit of the data resource in decimal degrees | 52.735966 |
West | The western-most limit of the data resource in decimal degrees | -4.140899 |
Responsible organisations | ||
Role | The point of contact is person or organisation with responsibility for the creation and maintenance of the metadata for the resource. | pointOfContact |
Organisation name | Natural Resources Wales (NRW) | |
Phone | 0300 065 3000 | |
Delivery point | Maes-y-Ffynnon | |
Postal code | LL57 2DW | |
Role | The distributor is the person or organisation that distributes the resource. | distributor |
Organisation name | Natural Resources Wales (NRW) | |
Phone | 0300 065 3000 | |
Delivery point | Maes-y-Ffynnon | |
Postal code | LL57 2DW | |
Role | The custodian is the person or organisation that accepts responsibility for the resource and ensures appropriate care and maintenance. If a dataset has been lodged with a Data Archive Centre for maintenance then this organisation is be entered here. | custodian |
Organisation name | Natural Resources Wales (NRW) | |
Phone | 0300 065 3000 | |
Delivery point | Maes-y-Ffynnon | |
Postal code | LL57 2DW | |
Role | The originator is the person or organisation who created, collected or produced the resource. | originator |
Organisation name | Various contractors | |
Phone | 01248 385500 | |
Delivery point | See Natural Resources Wales, Maes y Ffynnon | |
Postal code | LL57 2DW | |
Role | The originator is the person or organisation who created, collected or produced the resource. | originator |
Organisation name | CCW Marine Monitoring Team | |
Phone | 01248 385500 | |
Delivery point | Countryside Council for Wales, Maes y Ffynnon | |
Postal code | LL57 2DW | |
Dataset constraints | ||
20 Limitations on Public Access - Access constraints | ISO restriction code chosen from ISO 19115-1 Codelist | otherRestrictions |
20 Limitations on Public Access – Other constraints | Any restriction on the use of the resource such as the need to agree to certain licence conditions. | There are no access restrictions to this data. NRW may release, publish or disseminate it freely. |
21 Conditions for Access and Use - Use limitation | Any restrictions imposed on accessing the resource such as the need to agree to certain licence conditions. | © CNC/NRW 2010. There are no use restrictions on this data. Recipients may re-use, reproduce, disseminate this data free of charge in any format or medium, provided they do so accurately, acknowledging both the source and NRW's copyright, and do not use it in a misleading context. It is the recipient's responsibility to ensure the data is fit for the intended purpose, that dissemination or publishing does not result in duplication, and that it is fairly interpreted. Advice on interpretation should be sought where required. To avoid re-using old data, users should periodically obtain the latest version from the original source. |
Available data formats | ||
Data format | Format in which digital data can be provided for transfer | Database |
Version info | ||
Date of publication | The publication date of the resource or if previously unpublished the date that the resource was made publicly available via the MEDIN network. | 2010-12-31 |
Date of last revision | The most recent date that the resource was revised. | 2010-12-31 |
Metadata date | The date when the content of this metadata record was last updated. | 2018-07-05 |
Metadata standard name | The name of the metadata standard used to create this metadata | MEDIN Discovery Metadata Standard |
Metadata standard version | The version of the MEDIN Discovery Metadata Standard used to create the metadata record | Version 2.3.8 |
© OpenStreetMap contributors