Abstract
Background: The degradation of the water quality of the Baltic Sea is an ongoing problem, despite investments in measures to reduce external inputs of pollutants and nutrients from both diffuse and point sources. Excessive inputs of nutrients coming from the surrounding land are among the primary causes of the Baltic Sea eutrophication. Diffuse sources, of which most originate from agricultural activities, are two dominant riverine pollution pathways for both nitrogen and phosphorus. Recently, there is growing attention on the reuse of carbon, nitrogen and phosphorus from agricultural waste streams. However, to our knowledge, no comprehensive and systematic assessment of ecotechnologies focusing on recovery or reuse of these substances in the agricultural sector is available. Methods: This map will examine what evidence exists relating to effectiveness of ecotechnologies (here defined as ‘human interventions in social-ecological systems in the form of practices and/or biological, physical, and chemical processes designed to minimise harm to the environment and provide services of value to society’) in agriculture for the reuse of carbon and/or nutrients (nitrogen and phosphorus) in the Baltic Sea region and boreo-temperate systems. We will search for both academic and grey literature: English language searches will be performed in 4 bibliographic databases and search platforms, and Google Scholar, while searches in 38 specialist websites will be performed in English, Finnish, Polish and Swedish. The searches will be restricted to the period 2013 to 2017. Eligibility screening will be conducted at two levels: title and abstract (screened concurrently for efficiency) and full text. Meta-data will be extracted from eligible studies including bibliographic details, study location, ecotechnology name and description, type of outcome (i.e. recovered or reused carbon and/or nutrients), type of ecotechnology in terms of recovery source, and type of reuse (in terms of the end-product). Findings will be presented narratively and in a searchable geographically explicit database, visualised in an evidence atlas (an interactive geographical information system). Knowledge gaps and knowledge clusters in the evidence base will be identified and described.