Monitoring and assessment

Data on the status of the German marine areas in the North Sea and Baltic Sea are regularly collected as part of the Federal and State Monitoring Programme (BLMP). These areas include estuaries, transitional waters and coastal and marine waters in the exclusive economic zone. This monitoring is based on national, (sub-)regional and European legal requirements, including the regional marine conventions OSPAR and HELCOM, the Trilateral Wadden Sea Cooperation and relevant EU directives such as the Nitrates Directive, the Flora-Fauna-Habitat Directive (FFH Directive), the Water Framework Directive (WFD) and the Marine Strategy Framework Directive (MSFD). With the help of long-term and routine data collection, the state of the marine environment can be comprehensively documented in order to counteract negative developments.

Ships are used to collect biological, physico-chemical and hydrographic data. Fixed buoys measure hydrographic and physico-chemical values in continuous operation. The large-scale distribution of macroalgae, seagrass beds or marine mammals, for example, is observed from aeroplanes. The BLMP monitoring manual contains detailed information on measuring stations, parameters and methods, among other things. Continuous data collection can be supplemented by specific surveys and research activities as required. This traditional sampling is increasingly being supplemented by innovative methods. Satellites monitor the concentrations of chlorophyll and algal blooms, measuring devices on buoys or ferries take measurements autonomously. The screening of water, sediment and organism samples for the multitude of possible contaminants supplements the usual monitoring analysis of such samples for known indicator contaminants. The sampling of free plankton DNA in the sea (eDNA) serves as a supplementary analysis of marine biodiversity. AI-based methods are increasingly making it possible to automatically recognise and classify plankton species in underwater images.

Marine ecosystem models are often used for marine scientific questions. These models make it possible to determine reference states by reconstructing historical, unpolluted states of marine waters. In doing so, they can look much further back into the past than would be possible with the available measurement data. For the North Sea and Baltic Sea, ecosystem models are also used to determine necessary nutrient input reductions. In addition to marine models, modelling the situation in river catchments also plays a major role in marine protection. Such catchment area models can, for example, provide information on the sources of nutrient and contaminant inputs. The German Environment Agency is constantly developing its modelling capacities as part of research projects and uses model results to answer questions relating to marine science.

In order to recognise and counteract negative changes in the marine environment, a detailed inventory is first required. While in the past this was usually limited to localised interventions such as the dumping of sewage sludge, dredged material or drilling spoil from oil platforms, increasingly complex assessment procedures have been developed against the backdrop of new legal requirements. Individual indicators are initially assessed and then combined into an overall assessment using specific assessment rules. A fundamental distinction is made between the assessment of pressures (e.g. eutrophication, marine litter) and the assessment of the status of biological components (species, species groups or habitats).  For example, mature assessment procedures already exist for marine mammals, eutrophication and contaminants, while indicators and assessment procedures are currently being developed for other pressures such as noise pollution or the input of waste and other biological components such as food webs and pelagic habitats as part of research projects by the German Environment Agency, among others.

The WFD is implemented in Germany by the Surface Waters Ordinance (OGewV) and provides for an assessment of the chemical status and ecological potential of transitional and coastal waters every six years on the basis of threshold values and limit values defined in the OGewV. No transitional waters are defined in the Baltic Sea in Germany. In the North Sea, a distinction is made between transitional and coastal waters in accordance with the WFD. The chemical status is determined up to the 12 nautical mile zone. Priority and priority hazardous substances are monitored and assessed on the basis of environmental quality standards (EQS). The assessment of compliance with the EQS for the river basin-specific pollutants (PCBs, organotin compounds, various metals) is included in the assessment of the ecological status.  The ecological potential is determined in the transitional and coastal waters up to the 1 nautical mile zone and includes the assessment of the three biological quality elements phytoplankton, macrophytes and macrozoobenthos. A number of physico-chemical parameters (nutrients, oxygen, depth of visibility) are used to support the assessment.

Unlike the WFD, the MSFD does not make a strict distinction between the biological and chemical status in the assessment. However, three so-called ‘status descriptors’ (descriptor 1 ‘marine biodiversity’, descriptor 4 ‘food webs’ and descriptor 6 ‘seabed integrity’) describe the biological status of marine waters in the broadest sense. In addition, biotope types and biological features must be assessed in accordance with Annex III of the MSFD. In coastal waters, the WFD considers the three biological quality elements phytoplankton, macrophytes and macrozoobenthos. Under the MSFD, zooplankton, fish, seabirds and marine mammals are added. With the exception of microorganisms, all marine organism groups are thus covered by an EU directive for the first time. The MSFD also includes eight so-called ‘pressure descriptors’ - D2 Non-indigenous species, D3 commercial fish & shellfish, D5 Eutrophication, D7 Hydrographical conditions, D8 Contaminants, D9 Contaminants in seafood, D10 Marine litter and D11 Energy including underwater noise. Specific criteria and methodological standards for describing good environmental status were also defined for the descriptors in a supplementary decision by the EU Commission. A particular challenge in implementing the MSFD is the need to consider cumulative impacts. In addition, an economic and social analysis of the utilisation of the waters concerned and the costs of deterioration of the marine environment is required.

The Nitrates Directive provides for an assessment of nitrate concentrations in groundwater and surface waters, including coastal and marine waters, every four years. Long-term trends in nitrate concentrations at agreed monitoring sites are categorised into concentration classes with the aim of documenting the success of measures to reduce nitrate inputs into water bodies through decreasing trends. The resulting eutrophication assessment is based on the WFD and MSFD assessments.

As part of the regional marine conventions OSPAR and HELCOM, the status of the North-East Atlantic, including the North Sea and the Baltic Sea, is regularly assessed and published in the form of holistic status reports.  The HELCOM ‘State of the Baltic Sea Report’ and the OSPAR ‘Quality Status Report’ contain a large number of thematic status reports (e.g. on eutrophication, pelagic habitats, contaminants, food webs, marine litter, etc.) as well as a series of indicator assessments, pilot assessments and other assessments. These regional assessments are used by the North-East Atlantic and Baltic Sea countries to assess status under the MSFD. The assessment procedures used by OSPAR and HELCOM are therefore largely based on the requirements of the MSFD.

Through this co-operation between the three countries Germany, Denmark and the Netherlands, species, habitats and communities, human activities, selected pressures and the climate and geomorphology are described in regular quality status reports. The OSPAR and WFD procedures are primarily used for the assessment.

Under Article 11 of the Habitats Directive, the EU Member States monitor the conservation status of habitat types (Annex I) and species (Annexes II, IV and V) of European interest. The results of this monitoring form an important basis for the national report to be drawn up every 6 years in accordance with the Habitats Directive.