“…Yet, as has been noted by others and further discussed below, the unique geographical and biogeochemical features of the Baltic Sea make its ecosystem particularly vulnerable to external nutrient inputs and subject to eutrophication (e.g., Jansson, 1980;Voipio, 1981;Elmgren, 1989Elmgren, , 2001Jansson and Dahlberg, 1999). The symptoms and consequences of eutrophication at different scales and within different domains have been described and analyzed in hundreds of publications (e.g., Larsson et al, 1985;Davidan and Savchuk, 1989;Wulff et al, 2001b;Feistel et al, 2008;Cloern et al, 2016;Kuosa et al, 2017;Snoeijs-Leijonmalm et al, 2017b). From a mechanistic, explanatory point of view the eutrophication has also implicitly (Sjöberg et al, 1972;Stigebrandt and Wulff, 1987;Wulff and Stigebrandt, 1989) or explicitly (Savchuk, 1986(Savchuk, , 2002Savchuk and Wulff, 2009) been considered as an imbalance in biogeochemical cycles, resulting in nutrient accumulation when external inputs exceed permanent removals.…”