This dataset is a subset of "WFD Classification Status Cycle 2" and contains classification data for Dissolved Oxygen (DO) in transitional and coastal water bodies. Physico-chemistry, in this case Dissolved Oxygen, is a supporting element that underpins the ecological status of a transitional or coastal water body. Data consisting of DO and salinity records are run through the Dissolved Oxygen Water Framework Directive (WFD) classification tool. The actual (observed) 5%ile values of DO are compared with a predicted 5%ile value at average salinity in transitional waters, or with fixed values in coastal waters, that reflect pristine conditions. The comparison between the observed and expected 5%ile values of DO are used to produce a DO classification (High, Good or Moderate only) of a transitional or coastal water body for WFD purposes. Attribution statement: © Environment Agency copyright and/or database right 2015. All rights reserved.