Details

Autor(en) / Beteiligte

• Maemets, Helle
• Laugaste, Reet
• Palmik, Kadi
• Haldna, Marina

Titel

Response of primary producers to water level fluctuations of Lake Peipsi

Ist Teil von

• Proceedings of the Estonian Academy of Sciences, 2018-09, Vol.67 (3), p.231-245

Ort / Verlag

Tallinn: Estonian Academy Publishers

Erscheinungsjahr

2018

Quelle

EZB Electronic Journals Library

Beschreibungen/Notizen

• The amplitude of natural fluctuation between annual averages of the water level (WL) of Lake Peipsi (3555 [km.sup.2]) is 1.5 m. A study aimed to examine the impact of WL fluctuations on phytoplankton, macrophytes, and their epiphyton was performed annually at littoral stations during 2005-2015. Also the characteristics of pelagic water were collated with the WL. Changes in littoral and pelagial phytoplankton were similar, with the exclusion of massive wind-caused accumulations of cyanobacteria in the littoral. At the lowest WL a significant increase occurred in (a) the biomass of phytoplankton and the share of phytoplankton-derived organic carbon in water and (b) the species richness and biomass of macrophytes, including submerged plants and macroalgae. The abundance of epiphytes did not reveal a clear relation with the WL. The ratios of biomasses in the years with the lowest and the highest average WL were 2.2 for Potamogeton spp. and 2.6 for phytoplankton. The assessment of ecological status at the minimum and the maximum WL differs at least by one quality class. Decisions about ecological status based on phytoplankton and large filamentous green algae at low water may be contrary to decisions based on macrophytes: high biomasses of phytoplankton and macroalgae indicate hypertrophic status, but species-rich macrovegetation and high biomasses of charophytes and elodeids are considered to be characteristic of meso- to eutrophic water bodies. Key words: limnology, water level, phytoplankton, macrophytes, epiphytes, biomass, ecological assessment.