The data set includes the water flow and the actual, non-normalized, nutrient inputs (total nitrogen and phosphorous) of monitored river catchments and unmonitored areas as well as the nutrient inputs from point sources (municipal, industrial and aquaculture) that are directly discharging into the sea. The data covers the whole Baltic Sea drainage area and the years 1995-2021. Together the riverine and point source inputs provide the total land-based load of nutrients into the Baltic Sea. The data consists of several excel spreadsheets providing background info and actual load values. The spatial delineation of these catchments can be accessed through the metadata record for PLC Assessment data river catchments (https://metadata.helcom.fi/geonetwork/srv/eng/catalog.search#/metadata/d7b5404a-b3e1-4fe6-be35-a12055736783). The tabular and the spatial data includes the catchments that have a full time series of data for 1995-2021, and the nutrient load of rivers with incomplete time series are added to the adjacent unmonitored areas. The data is used in the HELCOM Baltic Sea Environmental Fact Sheet (BSEFS) on Waterborne nitrogen and phosphorus inputs and water flow to the Baltic Sea 1995-2021 that is published annually (https://helcom.fi/baltic-sea-trends/environment-fact-sheets/eutrophication/). The assessment data set is based on the reporting by HELCOM Contracting Parties within the Pollution Load Compilation framework (PLC). The assessment dataset is produced by the Baltic Nest Institute (BNI), Stockholm University together with the Danish Centre for Environment and Energy (DCE), Aarhus University from the original reported data. For a more detailed description of the spreadsheets and included data, please scroll down to lineage.

This dataset contains actual (non-normalized) riverine flow as well as actual atmospheric and waterborne inputs of nitrogen and phosphorus. In addition the dataset includes the normalized total nutrient inputs (atmospheric + waterborne) of nitrogen and phosphorus into the Baltic Sea. The data are used in the HELCOM core indicator on Inputs of nutrients (nitrogen and phosphorus) to the sub-basins 1995-2020 (https://indicators.helcom.fi/indicator/inputs-of-nutrients/). The river input data is based on reported riverine monitoring data as reported in HELCOM PLC data collection. Data on waterborne inputs, water flow and retention are reported by Contracting Parties to the PLC-Water database. The data are verified and quality assured using the PLC water database (https://nest.su.se/helcom_plc/) verification tools and national expert quality assurance. Atmospheric input data for all Baltic Sea sub-basins are available for the period 1990-2020. Atmospheric transport and deposition of nitrogen compounds are used for modelling atmospheric deposition to the Baltic Sea based on official emission data reported by EMEP Contracting Parties and expert estimates. Atmospheric input and source allocation budgets of nitrogen (oxidized, reduced and total) to the Baltic Sea basins and catchments were computed using the latest version of EMEP MSC-W model. Input of nutrients (N=Nitrogen, P=Phospohus) units are tonnes per year per HELCOM PLC Subbasin. Area delineation of HELCOM PLC subbasins can be accessed from https://maps.helcom.fi/website/mapservice/?datasetID=1456f8a5-72a2-4327-8894-31287086ebb5 Subbasin acronyms stand for: BOB: Bothnian Bay BOS: Bothnian Sea (including ARC = Archipelago Sea) BAP: Baltic Proper GUF: Gulf of Finalnd GUR: Gulf og Riga DS: Danish Straits (= WEB + SOU) (= Western Baltic + Sound) KAT: Kattegat BAS: The Baltic Sea

This online application serves as a joint regional tool to identify low risk routes for IMO Ballast Water Convention exemptions (A-4) for HELCOM and OSPAR marine areas. Data are provided following the port survey protocol described in the HELCOM/OSPAR Joint Harmonised Procedure. https://helcom.fi/wp-content/uploads/2021/01/HELCOM-OSPAR-Joint-Harmonized-Procedure-for-BWMC-A-4-exemptions_2020.pdf The database contains environmental data recorded from OSPAR and HELCOM ports as well as species observations and applies World Register of Marine Species (WoRMS) taxonomy. The data model used is based on Darwin Core format, with required extensions added. The database can be searched, viewed and downloaded using a specific web application. The whole database can be downloaded as a zipped ESRI File geodatabase. The HELCOM/OSPAR Ballast Water Exemptions Decision Support Tool was further developed in the EU INTERREG Baltic Sea Region project COMPLETE, following work developed with funding through the HELCOM ALIENS 2 and 3 and BALSAM projects by the HELCOM Secretariat and Germany (BSH/Brockmann consult). The data contained in the database are resulting from various sources and contains also historical legacy data from old projects. Main sources are listed below: - HELCOM and OSPAR countries national projects - HELCOM ALIENS 2 - HELCOM ALIENS 3 - HELCOM BALSAM

The aim of HELCOM Biodiversity database is to collate all available species observation data made available by HELCOM Contracting Parties from a single entry point. The database contains +1M species observations and applies World Register of Marine Species (WoRMS) taxonomy. The data model used is based on Darwin Core format, with required extensions added. Species observations are mostly pointwise observations, but also gridded observations are included for some species. The database can be searched, viewed and downloaded using a specific web application. The whole database can be downloaded as a zipped ESRI File geodatabase. Disclaimer: Data in the database is stemming from various sources. While there has been considerable quality assurance efforts, the accuracy of data can not be quaranteed.