“…Although nutrient level and physicochemical measurements (low COD, constant high oxygen saturation) confirmed Krčić as a pristine ecosystem, with year-long oligotrophic nutrient status, at the same time, this river showed intense seasonal fluctuations in its water regime. Longterm hydrological measurements on several gauging stations already affirmed the cyclic periodicity of the Krčić river brought on by summer droughts (Bonacci et al, 2006) and erratic but substantial rainfall periods (850-1750 mm along Krka River; Penzar & Penzar, 1990;Perica et al, 2005 previously reported in different environments, but with clear preference for carbonate-rich waters and unpolluted freshwater environments (Komárek, 1992;Margheri, Piccardi, Ventura, Viti & Giovannetti, 2003;Tavera, Novelo, & Lopez, 2013;Brinkmann et al, 2015). The dominance of cyanobacteria in this karst ecosystem concurred with similar research conducted on German karsts (Arp et al, 2010;Schneider et al, 2015).…”