4f4c4942-4343-5764-6473-313235373432 English Natural Resources Wales (NRW) Maes-y-Ffynnon, Penrhosgarnedd, Bangor, Gwynedd, LL57 2DW, Wales enquiries@naturalresourceswales.gov.uk http://naturalresources.wales/?lang=en 2026-03-26T09:38:18.396Z NRW 1.0 wel British National Grid (EPSG:27700) KiEco Freshwater Ecology: Diatoms - Geospatial KiEco Freshwater Ecology: Diatoms - Geospatial KiECO Ecoleg Dŵr Croyw Diatomau KiEco Freshwater Diatom Taxa.lyr KiEco Freshwater Diatom Site Details.lyr KiEco Freshwater Diatom Sample Metrics.lyr NRW Freshwater Phytobenthos - Diatoms 2026-03-25 NRW_DS125742 Freshwater diatoms (phytobenthos) are free-living microscopic plants that form a biofilm on submerged substrates such as rock/stone or large plants. They are used as an indicator of water quality because their silica shells are easy to identify under the microscope. This dataset is made up of the relative abundance of different species within the sample from freshwater diatom surveys conducted across Wales by Natural Resources Wales and former Environment Agency Wales. These surveys are conducted as part of on-going monitoring of river water quality for legislative requirements and to meet business drivers. A version of this data is available in the Darwin Core format as a CSV - Please see metadata here - NRW_DS123303 Freshwater diatoms (phytobenthos) are free-living microscopic plants that form a biofilm on submerged substrates such as rock/stone or large plants. They are used as an indicator of water quality because their silica shells are easy to identify under the microscope. This dataset is made up of the relative abundance of different species within the sample from freshwater diatom surveys conducted across Wales by Natural Resources Wales and former Environment Agency Wales. These surveys are conducted as part of on-going monitoring of river water quality for legislative requirements and to meet business drivers. A version of this data is available in the Darwin Core format as a CSV - Please see metadata here - NRW_DS123303 Planhigion microsgopig sy’n byw’n rhydd yw diatomau dŵr croyw (ffytobenthos) sy’n ffurfio bioffilm ar swbstradau tanddwr fel creigiau/cerrig neu blanhigion mawr. Fe’u defnyddir fel dangosyddion ansawdd dŵr oherwydd bod eu cregyn silica yn hawdd eu hadnabod o dan ficrosgop. Mae’r set ddata hon yn cynnwys digonedd cymharol y gwahanol rywogaethau o fewn y sampl o arolygon diatomau dŵr croyw a gynhaliwyd ledled Cymru gan Cyfoeth Naturiol Cymru a chan Asiantaeth yr Amgylchedd Cymru cyn hynny. Cynhelir yr arolygon hyn fel rhan o waith monitro parhaus ansawdd dŵr afonydd ar gyfer gofynion deddfwriaethol ac i fodloni gyrwyr busnes. Natural Resources Wales (NRW) Maes-y-Ffynnon, Penrhosgarnedd, Bangor, Gwynedd, LL57 2DW, Wales enquiries@naturalresourceswales.gov.uk http://naturalresources.wales/?lang=en Natural Resources Wales (NRW) Maes-y-Ffynnon, Penrhosgarnedd, Bangor, Gwynedd, LL57 2DW, Wales enquiries@naturalresourceswales.gov.uk http://naturalresources.wales/?lang=en Natural Resources Wales (NRW) Maes-y-Ffynnon, Penrhosgarnedd, Bangor, Gwynedd, LL57 2DW, Wales enquiries@naturalresourceswales.gov.uk http://naturalresources.wales/?lang=en Natural Resources Wales (NRW) Maes-y-Ffynnon, Penrhosgarnedd, Bangor, Gwynedd, LL57 2DW, Wales enquiries@naturalresourceswales.gov.uk http://naturalresources.wales/?lang=en Species distribution GEMET - INSPIRE themes, version 1.0 2008-06-01 geonetwork.thesaurus.external.theme.httpinspireeceuropaeutheme-theme NBN Atlas diatoms freshwater (fresh water, open water) (see also freshwater ecology) (see also inland waters,rivers,lakes) chrysophycota freshwater ecology freshwater biology NRW Thesaurus 2026-03-04 geonetwork.thesaurus.local.theme.converted_nrw-keywords There are no access restrictions on this data. NRW may release, publish or disseminate it freely. no limitations test © CNC/NRW Data may be re-used under the terms of the Open Government Licence providing it is done so, acknowledging both the source and NRW's copyright. It is the recipient's responsibility to ensure the data is fit for the intended purpose. Contains Natural Resources Wales information © Natural Resources Wales and Database Right. All rights Reserved. Open Government Licence English biota SeaVoX Vertical Co-ordinate Coverages 2021-01-06 Wales (WLS) -5.777741 -2.608865 51.240829 53.512067 1997-01-01 Geographic Information System 1 ESRI Feature Class Database Original Data held in WISKI Database https://datamap.gov.wales/capabilities/layergroup/6009/?ows_service=wms OGC:WMS WMS https://datamap.gov.wales/layergroups/geonode:nrw_freshwater_diatom_survey WWW:LINK-1.0-http--link View and Download Service 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 2010-12-08 This dataset has not been assessed for conformance to the referenced INSPIRE regulation. false Strict methodology is applied when sampling for freshwater diatoms. Diatom sampling is carried out as part of the routine freshwater ecology programme for a number of different reasons (WFD, Water Resources, ECN etc). These sites may be added to for investigative work, or on an ad hoc basis. Sampling areas are located with a larger survey area and must be representative of the overall survey area. A stone scrape method is the most commonly used method for sampling freshwater diatoms. However, where necessary alternative methods are used, for example in areas with no suitable substrate. Natural Resources Wales collect and analyse in excess of 350 diatom samples from rivers and lakes every year. Once samples are collected they analysed by NRW freshwater ecologists. Redactions Some information has be redacted to make the data openly available. This includes Third party data Data collected for ongoing investigations Cancelled or incomplete surveys Update Frequency This data is continually updated with the most surveys undertaken in the spring and autumn. Data from survey seasons is often not enter at the time of capture and can be several months before its is entered into the system. The external dataset is updated monthly to include new data, and may also contain corrections to previously published data due to quality assurance work. Information Warnings We do our best to avoid data quality problems, but as these datasets reflect the data we hold, they may contain errors. There is currently an error within system which means some TDI values are calculated incorrectly and give negative values. This issue has been identified by our developers and will be corrected in the next system update. The data is provided as a set of related data tables due to the quantity and structure of the data. A basic understanding of ecology and relational data is assumed. Data related to pollution incident investigations or protected species information is not released as locational information of these sites may be detrimental to ongoing investigations or species protection. Strict methodology is applied when sampling for freshwater diatoms. Diatom sampling is carried out as part of the routine freshwater ecology programme for a number of different reasons (WFD, Water Resources, ECN etc). These sites may be added to for investigative work, or on an ad hoc basis. Sampling areas are located with a larger survey area and must be representative of the overall survey area. A stone scrape method is the most commonly used method for sampling freshwater diatoms. However, where necessary alternative methods are used, for example in areas with no suitable substrate. Natural Resources Wales collect and analyse in excess of 350 diatom samples from rivers and lakes every year. Once samples are collected they analysed by NRW freshwater ecologists. Redactions Some information has be redacted to make the data openly available. This includes Third party data Data collected for ongoing investigations Cancelled or incomplete surveys Update Frequency This data is continually updated with the most surveys undertaken in the spring and autumn. Data from survey seasons is often not enter at the time of capture and can be several months before its is entered into the system. The external dataset is updated monthly to include new data, and may also contain corrections to previously published data due to quality assurance work. Information Warnings We do our best to avoid data quality problems, but as these datasets reflect the data we hold, they may contain errors. There is currently an error within system which means some TDI values are calculated incorrectly and give negative values. This issue has been identified by our developers and will be corrected in the next system update. The data is provided as a set of related data tables due to the quantity and structure of the data. A basic understanding of ecology and relational data is assumed. Data related to pollution incident investigations or protected species information is not released as locational information of these sites may be detrimental to ongoing investigations or species protection. Defnyddir methodoleg gaeth wrth samplu diatomau dŵr croyw. Mae’r gwaith samplu diatomau yn cael ei wneud fel rhan o’r rhaglen ecoleg dŵr croyw arferol am nifer o wahanol resymau (y Gyfarwyddeb Fframwaith Dŵr, adnoddau dŵr, y Rhwydwaith Newid Amgylcheddol ac ati). Gellir ychwanegu at y safleoedd hyn ar gyfer gwaith ymchwiliol, neu ar sail ad hoc. Mae ardaloedd samplu wedi’u lleoli gydag ardal arolwg fwy ac mae’n rhaid iddynt fod yn gynrychioliadol o’r ardal gyffredinol lle cynhelir yr arolwg. Dull crafu carreg yw’r dull a ddefnyddir amlaf ar gyfer samplu diatomau dŵr croyw. Fodd bynnag, lle bo angen, defnyddir dulliau amgen, er enghraifft mewn ardaloedd heb unrhyw swbstrad addas. Mae Cyfoeth Naturiol Cymru yn casglu ac yn dadansoddi dros 350 o samplau diatomau o afonydd a llynnoedd bob blwyddyn. Unwaith y bydd samplau wedi’u casglu, maent yn cael eu dadansoddi gan ecolegwyr dŵr croyw CNC. Golygiadau Mae rhywfaint o wybodaeth wedi’i olygu i sicrhau bod y data ar gael yn agored. Mae hyn yn cynnwys: • Data trydydd parti • Data a gasglwyd ar gyfer ymchwiliadau parhaus • Arolygon wedi’u canslo neu heb eu cwblhau Amlder Diweddaru Mae’r data hyn yn cael eu diweddaru’n barhaus, gyda mwyafrif yr arolygon yn cael eu cynnal yn y gwanwyn a’r hydref. Yn aml, nid yw data o dymhorau arolygon yn cael eu mewnbynnu ar adeg eu cipio a gall fod sawl mis cyn iddynt gael eu rhoi yn y system. Mae’r set ddata allanol yn cael ei diweddaru yn fisol i gynnwys data newydd, a gall hefyd gynnwys cywiriadau i ddata a gyhoeddwyd yn flaenorol oherwydd gwaith sicrhau ansawdd. Rhybuddion Gwybodaeth Gwnawn ein gorau i osgoi problemau ansawdd data, ond gan fod y setiau data hyn yn adlewyrchu’r data sydd gennym, gallant gynnwys gwallau. Ar hyn o bryd, mae gwall o fewn y system sy’n golygu bod rhai gwerthoedd y Mynegai Diatom Troffig (TDI) yn cael eu cyfrifo’n anghywir ac yn rhoi gwerthoedd negyddol. Mae’r mater hwn wedi’i nodi gan ein datblygwyr a bydd yn cael ei gywiro yn niweddariad nesaf y system. Darperir y data fel set o dablau data cysylltiedig oherwydd maint a strwythur y data. Tybir dealltwriaeth sylfaenol o ecoleg a data perthynol. Ni ryddheir data sy’n ymwneud ag ymchwiliadau i achosion o lygredd neu wybodaeth am rywogaethau a warchodir gan y gallai gwybodaeth am leoliad y safleoedd hyn fod yn niweidiol i ymchwiliadau parhaus neu waith gwarchod rhywogaethau.