The pressure layer represents biological pressure caused by introduction of non-indigenous species. The data is obtained from core indicator Trend in the arrival of new non-indigenous species (BSEP 129b: http://www.helcom.fi/Lists/Publications/BSEP129B.pdf). For the Baltic Sea Impact Index, the layer was normalized.

Input of impulsive anthropogenic sound includes impulsive events from 2011-2016 • Seismic surveys (HELCOM-OSPAR Registry; national data call submissions as lines in the folder of data) • Explosions (HELCOM-OSPAR Registry) • Pile driving (HELCOM-OSPAR Registry) • Airguns (HELCOM-OSPAR Registry) For the different event types, numeric intensity value was used to represent the pressure as categorized in HELCOM-OSPAR Impulsive noise registry. All nationally reported seismic surveys were given intensity values “Very low” (0.25) - Very low (0.25) - Low (0.5) - Medium (0.75) - High (1) The impact distance has not been taken into account due to the different nature of separate datasets used for the pressure layer. We acknowledge that e.g. pile driving and airguns may impact up to 20 km from the source event. The spread of the sound wave depends on the sound frequency, water salinity, temperature and density.

The dataset contains data on bridges and other constructions. The dataset is constructed from Open Street Map “roads” shapefiles downloaded through Geofabrik by extracting all features where attribute bridges=1. It should be noted that the dataset contains major bridges and all other smaller constructions that have been classified as bridges in Open Street Map. The coverage for the dataset is whole Baltic.

The dataset was created in order to update the information regarding underwater pipelines in the Baltic Sea Region for the HELCOM Assessments. Data was collected by the HELCOM Secretariat during 2015. The data was made available by HELCOM Contracting Parties in response to data request. The data was received from Denmark, Germany, Finland and Poland. The report data represents constructions on respective territorial waters, authorized facilities and activities from 2015. The activity was declared as not relevant in Lithuanian area. From Estonia, Latvia, Lithuania, Russia and Sweden no data was reported. Attribute specification and units: NAME COUNTRY CAPACITY (MW) STATUS (Operational, Under Construction, Application Submitted, Planned, Unknown) SOURCE

Potential cumulative impacts on benthic habitats is based on the same method than http://metadata.helcom.fi/geonetwork/srv/eng/catalog.search#/metadata/9477be37-94a9-4201-824a-f079bc27d097, but is focused on physical pressures and benthic habitats. The dataset was created based on separate analysis for potential cumulative impacts on only the benthic habitats, as these are particularly affected by physical pressures. In this case the evaluation was based on pressure layers representing http://metadata.helcom.fi/geonetwork/srv/eng/catalog.search#/metadata/ea0ef0fa-0517-40a9-866a-ce22b8948c88 and http://metadata.helcom.fi/geonetwork/srv/eng/catalog.search#/metadata/05e325f3-bc30-44a0-8f0b-995464011c82, combined with information on the distribution of eight broad benthic habitat types and five habitat-forming species (http://metadata.helcom.fi/geonetwork/srv/eng/catalog.search#/metadata/363cb353-46da-43f4-9906-7324738fe2c3, http://metadata.helcom.fi/geonetwork/srv/eng/catalog.search#/metadata/f9cc7b2c-4080-4b19-8c38-cac87955cb91, http://metadata.helcom.fi/geonetwork/srv/eng/catalog.search#/metadata/264ed572-403c-43bd-9707-345de8b9503c, http://metadata.helcom.fi/geonetwork/srv/eng/catalog.search#/metadata/822ddece-d96a-4036-9ad8-c4b599776eca and http://metadata.helcom.fi/geonetwork/srv/eng/catalog.search#/metadata/ca327bb1-d3cb-46c2-8316-f5f62f889090). The potential cumulative impacts has been estimated based on currently best available data, but spatial and temporal gaps may occur in underlying datasets. Please scroll down to "Lineage" and visit http://stateofthebalticsea.helcom.fi/cumulative-impacts/ for more info.

Data of fish farming facilities along the Baltic coast. Annual and average finfish production and nutrient load (total phosphorus and total nitrogen) is given, if known. The data was made available by HELCOM Contracting Parties in response to data request. The data was received from Denmark, Finland, Germany and Sweden. The activity was declared as not relevant for Estonia, Latvia, Lithuania and Poland, thus there is no activity within those Contracting Parties. No data received from Russia. Nutrient inputs from fish farms in Denmark are calculated on the basis of production data. From Germany only the locations for the fish farming facilities are given. Information on the annual production and nutrient loads are confidential for reasons of competition and not accessible. Some numbers that were missing on nutrient input in Sweden have been calculated by SCB, Statistics Sweden (red numbers) based on average input/ amount produced fish. No exact area (km2) of the finfish mariculture was available, hence an estimate is given if been possible to calculate. Attribute specification and units: X_ETRS89: X coordinate point Y_ETRS89: Y coordinate point Subbasin: Baltic Sea sub basin Country: Country id (DK = Denmark, FI = Finland, SE = Sweden) County: County Name: Name of the fish farming company Comments: Notes regarding the data Area: Estimated area (km2) of finfish mariculture (value is given, if information was available) Pr_Sum_ton: Total (Sum) production in tonnes Pr_Av_ton: Average production (tonnes)/year P_Sum_ton: Total phosphorus load in tonnes P_Av_ton: Average phosphorus load (tonnes)/year N_Sum_ton: Total nitrogen load in tonnes N_Av_ton: Average nitrogen load (tonnes)/year Pr2011_ton – Pr2015_ton: Annual production (tonnes/year) P_2011_kg – P_2015_Kg: Annual phosphorus loading in kilograms (Kg P / year) N_2011_kg – N_2015_Kg: Annual nitrogen loading in kilograms (Kg N / year)

Data set represents dredging activities around the Baltic Sea. The dataset contains information about the dredging activity and for some the type (capital, maintenance) and the year of activity as reported by HELCOM Contracting Parties in response to data request. The dredging data is missing from Denmark.

Pressure layer combines all human activities that cause changes to hydrological conditions. The human activities were presented as point data which were given spatial extents (given below). The pressure value was given as the proportion of the grid cell under the pressure. The following human activities were combined into the changes to hydrological conditions layer; - Hydropower dams (a 1km2 grid cell in the river estuary was selected) - Water course modification (1 km) - Wind turbines (operational, 0.3 km, linear decline) - Oil platforms (0.5 km, linear decline) The human activity datasets were first processed separately covering the whole Baltic Sea and then summed together and overlapping areas were dissolved to remove double counting. Attenuation gradients are assigned to each layer as described above. Area effected decreases when distance from avtivity increases. Layer was normalized.

This dataset contains point data describing the location of oil platforms in the Baltic Sea. The dataset is complete in Baltic sea coverage as it contains two known oil platforms.

Locations of the coastal protection structures. The dataset contains information about the coastal defence structure type and for some the structure length (m) and the year of construction. The data was made available by HELCOM Contracting Parties in response to data request. The data was received from Denmark, Estonia, Germany, Finland, Poland and Sweden. The activity was declared as not relevant in Lithuanian area. From Latvia and Russia no data was reported. Attribute specification and units Country: Country Type: Modification structure type Const_year: Year of construction Estimated: Estimated date of completion if under construction (Estonia) or the year of environmental permit if year of construction is lacking (Finland) Out_of_use: Year when costal defence structure has been taken out of use Measure: Additional information about the modification structure Length: Length of the modified coastline (m) width: Width of the modification structure (m) Area: Area of the modification structure (km2) X_Lon: Original X (Longitude) coordinate point (Finland)