Dissolved oxygen, temperature and salinity measurements in coastal and estuarine waters in the UK from 1990 to 2018

notPlanned

Sampling was carried out during fieldwork by the Environment Agency (EA), Natural Resources Wales (NRW), the Scottish Environmental Protection Agency (SEPA) and the Department of Agriculture, Environment and Rural Affairs (DAERA) in Northern Ireland. Data were collected and quality assured following agreed protocols in the UK’s Coordinated Environmental Monitoring Programme (CEMP). All fieldwork was conducted using boat- or shore- based sampling. Sampling and analytical methods followed standard procedures and guidelines, as described in reports and scientific publications (e.g. Best et al 2007, Greenwood et al 2010, Queste et al 2013). All methods were based on SCA (1979) protocols, with traceable quality assurance (QA) and external QA, e.g. through QUASIMEME (Quality Assurance of Information on Marine Environmental Monitoring in Europe), although methods have changed since the 1990's. For the EA, for example, physical samples were originally collected, preserved with a mercury solution and analysed later in the lab using Winkler titrations. Spot or semi continuous data were obtained for development and calibration of probes. The National Laboratory Service (NLS) then moved to sensor-based monitoring. Data were collected from survey vessel/s using an Idronaught instrument with a dissolved oxygen (DO) probe (diffusion initially, then optical), typically as spot samples from about 1-2m (lowered or from a pump supply). DO was measured as percentage saturation and concentration (mg/l) using daily in air calibration and 6 monthly laboratory zeroing if necessary. Close to shore, data were collected with a YSI instrument with a DO probe. Waterbodies are defined by the European Union’s Water Framework Directive, of which there are 743 around Scotland, Wales and England, ranging in size from 0.02km2 to 183,331.20 km2. Waterbodies are grouped into 29 regions. Water samples were available from 208 of the waterbodies and 25 regions References: Best M, Wither AW, Coates S (2007) Dissolved oxygen as a physico-chemical supporting element in the Water Framework Directive. Mar Pollut Bull 55:53–64. doi: 10.1016/j.marpolbul.2006.08.037 Foden J, Devlin MJ, Mills DK, Malcolm SJ (2011) Searching for undesirable disturbance: an application of the OSPAR eutrophication assessment method to marine waters of England and Wales. Biogeochemistry 106:157–175. doi: 10.1007/s10533-010-9475-9 Greenwood N, Parker ER, Fernand L, et al (2010) Detection of low bottom water oxygen concentrations in the North Sea; implications for monitoring and assessment of ecosystem health. Biogeosciences. pp 1357–1373 Queste BY, Fernand L, Jickells TD, Heywood KJ (2013) Spatial extent and historical context of North Sea oxygen depletion in August 2010. Biogeochemistry 113:53–68. doi: 10.1007/s10533-012-9729-9 SCA (1979). Standing Committee of Analysts. Dissolved oxygen in natural and waste waters: methods for the examination of waters and associated materials. Her Majesty's Stationery Office, London. ISBN 0 11 751442 X Smith AF, Fryer RJ, Webster L, et al (2014) Setting background nutrient levels for coastal waters with oceanic influences. Estuar Coast Shelf Sci 145:69–79. doi: 10.1016/j.ecss.2014.04.006