The data set comprises temperature and salinity measurements, and nutrient concentrations from strategic locations in the offshore and oceanic waters around Scotland. Additional parameters, including concentrations of dissolved oxygen, suspended particulate material, and chlorophyll pigments, are available for many sites. The measurements are from research cruises taking place typically three times each year, and dating back to 1989. The data set now forms one of the longest hydrographic time series in the world. Marine Scotland scientists use the research vessels FRV Scotia and FRV Alba na Mara to deploy Conductivity, Temperature and Depth (CTD) probes from the sea surface to the seabed at a number of fixed stations and other sites of interest. The CTD rigs include ancillary sensors and water sampling devices, which are used to collect water samples for calibration of the in situ sensor data. In 2001, short and long term moorings were also added to Marine Scotland’s data collection activities with current meters, temperature recorders and water level recorders being deployed on moorings in waters around Scotland. Similar to the CTD casts, the research vessels FRV Scotia and FRV Alba na Mara are used to deploy and recover the moorings. Marine Scotland undertakes research and monitoring in both the freshwater and marine environments to provide scientific and technical advice on a wide range of marine and fisheries issues. This is with an aim to examine how the environmental status of Scotland’s seas and oceans varies in response to many pressures, including wide scale natural variability. This will help secure the Scottish Governments’ vision of clean, healthy, safe, productive and biologically diverse marine and coastal environments, managed to meet the long term needs of nature and people. Marine Scotland is part of, and funded by the Scottish Government. Marine Scotland makes annual submissions of CTD and mooring data to BODC.