Field evidence of the influence of aquatic macrophytes on water quality in a shallow eutrophic lake over a 13-year period

• Autor(a) principal: Albertoni,Edélti Faria
• Data de Publicação: 2014
• Outros Autores: Palma-Silva,Cleber, Trindade,Claudio Rossano Trindade, Furlanetto,Leonardo Marques
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Acta Limnologica Brasiliensia (Online)
• Texto Completo: http://old.scielo.br/scielo.php?script=sci_arttext&pid=S2179-975X2014000200008
• topic: floating macrophytes; submerged macrophytes; shallow subtropical lakes; clear and turbid waters; southern Brazil

AIM: The main objective of this work is to describe the changes in water characteristics of a shallow subtropical lake, in periods with and without growing of macrophytes, related to periods of clear-macrophyte dominance and turbid-phytoplankton dominance states. METHODS: The study was conducted in Biguás Lake, in the south coastal plain of Brazil (32° 04&#x27 43" S and 52° 10&#x27 03" W). Samplings were carried out monthly between October 2000 and November 2013. The limnological variables measured in the water column were dissolved oxygen (DO), water temperature, pH, electrical conductivity (EC), chlorophyll-a, total nitrogen (TN), total phosphorous (TP) and suspended material (SM). Data were grouped according to periods with macrophyte growth dominance (MD) and without macrophytes, with phytoplankton dominance (PD), and applied t- tests among TP, TN, Chlorophyll-a and SM. During macrophyte growth we estimated the coverage (%) and biomass variation of plants. RESULTS: Over the 13 years, the lake was well oxygenated, alkaline, and with a temperature variation according to subtropical seasonality. The lower values of all of the limnological variables were verified during periods of macrophyte growth, characterizing periods of clear and turbid waters. CONCLUSIONS: The influence of aquatic macrophytes in improving water quality in this shallow lake during the studied period, reducing nutrient concentrations, chlorophyll-a and suspended material in water, favoring the maintenance of a clear water state, was verified.