Ecological status assessment of Skalenski Lakes (Bulgaria)

Abstract

Over the past decade new ecological indices based on phytoplankton and macrophytes were developed as part of the tools for assessment of the ecological status of water bodies. This study demonstrates the applicability of two of them (Assemblage index /Q/ and Algae Group Index /AGI/) for evaluation of water bodies from a lake type L4 as well as their comparability. Assessment of the ecological status of two lake ecosystems was performed in order to ensure successful protection, enhancement and management of lowland and semi-mountain lakes in Bulgaria. Data on the aquatic flora from Golyamo Skalensko Lake and Malko Skalensko Lake over a period of two years were used to assess their ecological status. In addition, the toxic potential of the established dominant cyanoprokaryotic species was also evaluated. Phytoplankton- and macrophyte-based metrics resulted in complementary evaluation of temporary and long-term environmental conditions. Despite the hydraulic connection and proximity between the two lakes, Golyamo Skalensko Lake and Malko Skalensko Lake appear as completely different ecosystems, according to the phytoplankton structure (species composition, number of species, abundance, seasonal succession), macrophytes and ecological status.

Assessment of cyanoprokaryote blooms and of cyanotoxins in Bulgaria in a 15-years period (2000-2015)

“…Negative results for cyanotoxins have been published by Pavlova (2007), Pavlova et al (2007Pavlova et al ( , 2013aPavlova et al ( , 2014Pavlova et al ( , 2015, Teneva et al (2014) and Georgieva et al (2015) for 13 WBs and for some samples from 11 WBs with previously detected toxins (Tab. 3).…”

“…Teneva et al 2009Teneva et al , 2010aTeneva et al . 2011Teneva et al . 2014Stoyanov et al 2012 Aphanizomenon fos-aquae Ralfs ex Born.…”

“…In the same reservoir HPLC peaks showed the presence of nodularins, but their amounts were given only as a total of microcystins/nodularins (MC/NOD) detected by ELISA (Teneva et al, 2011). In the same way, MC/NOD totals were provided for the reservoirs Borovitsa, Enitsa, Kayabash 2, Krushovitsa, Studen kladenets and Trakiets (Teneva et al, 2009(Teneva et al, , 2010a(Teneva et al, , 2011(Teneva et al, , 2014Stoyanov et al, 2012). The types of microcystins were indicated in the publications for 10 WBs but only for 9 of them the values have been provided (Tab.…”

“…This study compiles and evaluates the currently available data on phytoplankton and relevant environmental data on Bulgarian WBs (mainly reservoirs and lakes) gathered during the period 2000-2015 (Stoyneva, 2003(Stoyneva, , 2010(Stoyneva, , 2014(Stoyneva, , 2015Beshkova and Botev, 2004;Kalchev et al, 2004;Traykov, 2005;Pavlova et al, 2006Pavlova et al, , 2013aPavlova et al, , 2014Pavlova et al, , 2015Beshkova et al, 2008aBeshkova et al, , 2008bBeshkova et al, , 2012Pavlova, 2007;Tsanev and Belkinova, 2008;Teneva et al, 2009Teneva et al, , 2010aTeneva et al, , 2010bTeneva et al, , 2011Teneva et al, , 2014Cheshmedjiev et al, 2010aCheshmedjiev et al, , 2013Stoyanov et al, 2012Stoyanov et al, , 2013Stoyanov et al, , 2016Stoyanov, 2014Stoyneva et al, 2013Belkinova et al, 2014;Dimitrova et al, 2014aDimitrova et al, , 2014bDochin andStoyneva, 2014, 2015;Dochin, 2015;Georgieva et al, 2015).…”

“…The assessment of cyanotoxins registered in the country in relation to their potential producers is based on the works of Pavlova (2007), Pavlova et al (2006Pavlova et al ( , 2007Pavlova et al ( , 2013aPavlova et al ( , 2014Pavlova et al ( , 2015, Teneva et al (2009Teneva et al ( , 2010aTeneva et al ( , 2010bTeneva et al ( , 2011Teneva et al ( , 2014, Stoyanov et al (2012) and Georgieva et al (2015) -Tabs. 2 and 3.…”