Baltic ALgae COmmunity AnalySIs System is a classification system for macrophytes (defined as macroalgae and angiosperms).
Its concept has been developed by University Rostock, working group Aquatic Ecology between 2004–2006 and has been revised, supplemented and finalized regarding structure, classification matrix and monitoring by MariLim GmbH between 2006–2008. An evaluation of the assessment system with the data sets collected so far has been made in 2013 resulting in specific improvements of the assessment. In the years 2016 and 2017 the monitoring already was performed according to the improved methods.
The classification scheme is valid for open coastal waters (national water type B3) and combines the evaluation of soft and hard bottom vegetation. BALCOSIS covers all representative perennial vegetation components of the German Baltic open coastal waters (eelgrass beds, Fucus and red algae phytal). A set of in total seven parameters (= metrics) has been compiled for each of those habitats and for each metric a 5-step classification system has been developed. This allows evaluating, if certain vegetation elements or metrics may react different towards anthropogenic stressors.
How the assessment system BALCOSIS is to be used is described on the website surface waters assessment.