DOME (Marine Environment) is a data portal used by OSPAR, HELCOM, AMAP and Expert Groups in the management of chemical and biological data for regional marine assessments. A large portion of the data held are monitoring data submitted for the OSPAR CEMP and HELCOM COMBINE monitoring programmes and therefore follow specific monitoring programme guidelines. While these programmes have key components which are monitored yearly at defined stations, components which are under development are also included. The result is a broad spectrum of chemical parameters from metals, PAHs, brominated flame retardants, TBT and TBT effects in sediment and biota, to histopathology, ocean acidification and benthos and plankton data. DOME also includes methods and quality assurance data such as the reporting of uncertainty on a single component basis to help in assessing comparable data. Data are reported according to the Environmental Reporting Format version 3.2 in order to be quality controlled and entered into the database. Submissions of data may be made at any time.