Volunteer Diver Seagrass Zostera marina Surveys Porth Dinllaen (2009)

Seagrass is the only marine flowering plant found subtidally in the UK and seagrass beds are considered of National importance. In 2009 Zostera marina was the focus of former Countryside Council for Wales (CCW), now part of Natural Resources Wales (NRW), volunteer dive surveys at Porth Dinllaen in Pen Llyn a'r Sarnau Special Area of Conservation (SAC) to estimate the extent of the bed. The survey is a continuation of a 2008 pilot, and is due to be re-surveyed before 2012 to start to build up a picture of variation in the extent of the seagrass bed at the site. The main objectives of this project were to: 1. Test methods to measure extent of large seagrass beds using volunteers 2. Estimate density and measure depth of live seagrass in different parts of the bed 3. Make note of any unusual features of the seagrass bed 4. Compare with results and success of 2008 surveys.

Identification

Identifier
NRW_DS111487
Alternative Title
  • 2009 CCW Porth Dinllaen Seagrass Survey MRMES00200000011
  • Seagrass surveys in Porth Dinllaen
Metadata Language
English
Lineage

Data is captured by using volunteer divers who are CMAS 2 star qualified or equivalent with a minimum of 60 dives each. Volunteers estimated the extent of large seagrass beds using rapid unmarked transects analysis, using a GPS surface tracking buoy, noting the time and depth of features of the seagrass bed (eg: where the bed starts or stops, or the position of 'mooring scars'). This method was compared with the success when some divers swam towards a fixed underwater acoustic marker (transponder) with a homing device, noting the distance and bearing to the transponder to note the key features. Wherever possible, quadrats were taken at stations along transects and the presence of flowering, seeding and wasting were noted, together with any associated, potentially threatening or BAP species. Survey methods and success were compared to the 2008 survey methods and results, and the technique's feasibility for future volunteer surveys discussed.
Dataset Reference Date (Publication)
2009-12-31
Owner
  Natural Resources Wales (NRW) -
Maes-y-Ffynnon, Penrhosgarnedd, Bangor, Gwynedd, LL57 2DW, Wales
http://naturalresources.wales/?lang=en
Originator
  Various including volunteer recorders -
c/o Natural Resources Wales, Maes y Ffynnon, Penrhosgarnedd, Bangor, Gwynedd, LL57 2DW, Wales
http://naturalresourceswales.gov.uk/splash?orig=/
 

Extent

Extent

Geographic Extent
GWYNEDD - GWYNEDD
N
W
E
S
Map representing the geographic extent of the dataset


 

Vertical Extent

Medin Extent Keyword
benthic boundary layer

Vertical Extent

Minimum value (metres)
0
Maximum value (metres)
-6.5
Vertical CRS
 
 

Distribution

Distribution

Format Type and Description
  • Database ( )

    Specification

    Seasearch data held in Marine Recorder.

  • Geographic Information System ( )

    Specification

    Transects and density data are MapInfo TAB files.

  • Documents ( )

    Specification

    Summary report as word file.

  • Delimited ( )

    Specification

    Species data held in excel spreadsheets.

  • Image ( )

    Specification

    Images as JPGs

 

Quality

Data quality

Quality Scope
Dataset
Conformity
Commission Regulation (EU) No 1089/2010 of 23 November 2010 implementing Directive 2007/2/EC of the European Parliament and of the Council as regards interoperability of spatial data sets and services
Explanation

This dataset has not been assessed for conformance to the referenced INSPIRE regulation.
Degree
false
Lineage

Data is captured by using volunteer divers who are CMAS 2 star qualified or equivalent with a minimum of 60 dives each. Volunteers estimated the extent of large seagrass beds using rapid unmarked transects analysis, using a GPS surface tracking buoy, noting the time and depth of features of the seagrass bed (eg: where the bed starts or stops, or the position of 'mooring scars'). This method was compared with the success when some divers swam towards a fixed underwater acoustic marker (transponder) with a homing device, noting the distance and bearing to the transponder to note the key features. Wherever possible, quadrats were taken at stations along transects and the presence of flowering, seeding and wasting were noted, together with any associated, potentially threatening or BAP species. Survey methods and success were compared to the 2008 survey methods and results, and the technique's feasibility for future volunteer surveys discussed.
 

Keywords

Keywords

GEMET - INSPIRE themes, version 1.0
Type
Theme

Citation

Date (Publication)
2008-06-01
Code
geonetwork.thesaurus.external.theme.httpinspireeceuropaeutheme-theme

Keywords

NRW Thesaurus
  • eelgrass
  • posidoniaceae
  • zostera marina
  • zostera
  • Pen Llyn a'r Sarnau cSAC
  • seagrasses (see also potamogetonaceae and hydrocharitaceae)
  • Porth Dinllaen
Type
Theme

Citation

Date (Publication)
2026-03-04
Code
geonetwork.thesaurus.local.theme.converted_nrw-keywords

Keywords

SeaDataNet Parameter Discovery Vocabulary
Type
Theme

Citation

Date (Publication)
2024-06-19
Code
geonetwork.thesaurus.external.theme.rdf+xml

Keywords

IPSV Subjects List
  • Volunteers
Type
Theme

Citation

Date (Publication)
2020-11-18
Code
geonetwork.thesaurus.external.theme.subjects
 

Spatial Reference System

Code
Latitude and Longitude (EPSG::4326)
 

Content

Content Information

NRW Profile

Custom Elements

 

Constraints

Constraints

Limitations on Public Access and Use

Restriction type
Other restrictions
 

Access Constraints Directive

Limitations
no limitations
 

Access Constraints Text

Other constraints

The following data is considered OS derived data and is therefore jointly owned by NRW and the Ordnance Survey. NRW may release, publish or disseminate this data freely; providing recipients are made aware of use restrictions (See general use restrictions).
 

Use Constraints

Use constraints type
Other restrictions
Other constraints

© CNC/NRW and © Crown copyright 2009. All rights reserved. Natural Resources Wales, AC0000849444 Third parties seeking to re-use this data require a Licence issued by NRW. It allows re-use, reproduction and dissemination in any format or medium but only for non-commercial purposes, according to the terms and conditions of the Licence. Those seeking commercial re-use require a commercial licence available from the OS.
 

Attribution Statement

Other constraints

Contains Natural Resources Wales information © Natural Resources Wales and Database Right. All rights Reserved. Contains Ordnance Survey Data. Ordnance Survey Licence number AC0000849444. Crown Copyright and Database Right.
 
 
 

Metadata

Metadata

File Identifier
4f4c4942-4343-5764-6473-313131343837 XML
Metadata Language
English
Parent Identifier
Across Wales Diving Monitoring Project (2004)

NRW_DS109743
Resource type
Dataset
Metadata Date
2026-03-05T10:27:31.568Z
Metadata Standard Name
NRW
Metadata Standard Version

1.0

pointOfContact
  Natural Resources Wales (NRW) -
Maes-y-Ffynnon, Penrhosgarnedd, Bangor, Gwynedd, LL57 2DW, Wales
http://naturalresources.wales/?lang=en
 
 

Publishing Body

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