The Baltic Nest system contains several models when put together give a good idea about how different decisions affect eutrophication in the Baltic Sea.

The Nest system was developed in the eight year (1999-2006) program MARE (Marine Research on Eutrophication - a scientific base for cost-effective measures for the Baltic Sea). Sinced the MARE-project ended the Nest system has been maintained and developed by the Baltic Nest Institute.

The system consists of several models, for example BALTSEM and SANBALTS, the large Baltic Environmental Database (BED) and the Data Assimilation System (DAS). Together they generate support for decision-making, and have been valuable in international negotiations between the Baltic countries, as well as used in many research projects. The system is constantly developing.

HELCOM Baltic Sea Action Plan

Nest has played an instrumental role in identifying the nutrient reductions (Maximum allowable nutrient input) necessary to achieve "Good environmental status” in the Baltic Sea as defined by international decision makers in HELCOM. The reduction scheme was adopted in the rescue plan for the Baltic Sea, Baltic Sea Action Plan, by HELCOM in November 2007. 

During 2013, the Baltic Sea Action Plan was was renegotiated within HELCOM and the Baltic Sea countries. Decisions included reductions in the supply levels of nitrogen and phosphorus, overall for the Baltic Sea as well as from every country (Country-Allocated Reduction Targets, CART). In this work, the Baltic Nest Institute and the Nest model also played a key role.


The Nest system is freely available online and can be used in an expert mode and a management mode. 

More information about the Nest system and the different versions is found here. Information on the technical specifications and how to download the tool click here.

The manual for the system can be read here.