Factors influencing lake recovery from eutrophication — the case of Basin 1 of Lake Balaton

• Published in: Water research (Oxford) 2001-03, Vol.35 (3), p.729-735
• Main Authors: ISTVANOVICS, Vera, SOMLYODY, Laszlo
• Format: Article
• Language: English
• Subjects: Animal, plant and microbial ecology; Applied ecology; Applied sciences; Biological and medical sciences; Biomass; Calcium - analysis; Continental surface waters; Cyanobacteria - growth & development; Cylindrospermopsis raciborskii; Earth sciences; Earth, ocean, space; Ecotoxicology, biological effects of pollution; Engineering and environment geology. Geothermics; Eukaryota; Eutrophication; Exact sciences and technology; Fresh Water; Fresh water environment; Freshwater; Fundamental and applied biological sciences. Psychology; Geologic Sediments; Hungary; internal load; Models, Biological; Natural water pollution; OECD model; Phosphorus - analysis; Phytoplankton - isolation & purification; Pollution; Pollution, environment geology; pre-reservoir; sediment mass balance; Water Microbiology; Water Purification - methods; Water treatment and pollution
• ISSN: 0043-1354; 1879-2448
• DOI: 10.1016/S0043-1354(00)00316-X

Lake Balaton is a large, shallow, and calcareous lake that was subject to a rapid eutrophication during the 1970s. Management measures taken from the mid-1980s decreased the phosphorus load to the lake from 0.5 to 0.3 g P m −2 yr −1. Using long-term load and water quality data, we analyse the response of the formerly hypertrophic Basin 1 of the lake by the means of simple empirical models. Several factors that are commonly neglected during studies of lake recovery modified the apparent settling velocity of total P and consequently, the biomass of the phytoplankton. These factors included the loads of calcium and suspended solids, the loading ratio of the dissolved to particulate phosphorus, and blooming of the dominant cyanobacterium, Cylindrospermopsis raciborskii. Due to the rapid immobilisation of the mobile phosphorus in the surface sediments, moderate reduction (45–50%) in the external load resulted in a surprisingly fast and significant improvement of the water quality in the hypertrophic southwestern basins of the lake.