Trophic State Evolution over 15 Years in a Tropical Reservoir with Low Nitrogen Concentrations and Cyanobacteria Predominance

Author(s)

de Souza Beghelli, Frederico Guilherme ^[1] ; Frascareli, Daniele ^[1] ; Martins Pompeo, Marcelo Luiz ^[2] ; Moschini-Carlos, Viviane ^[1]

Affiliation

^[1] Sao Paulo State Univ UNESP, Inst Sci & Technol Sorocaba, Ave Tres Marco 511, BR-18087180 Sorocaba, SP - Brazil

^[2] Sao Paulo Univ USP IB, Inst Biol, Dept Ecol, Travessa 14, 321, BR-05508090 Sao Paulo, SP - Brazil

• Document type: Journal article
• Source: WATER AIR AND SOIL POLLUTION; v. 227, n. 3 MAR 2016.
• Web of Science Citations: 8

Abstract

Anthropic eutrophication is one of the most widespread problems affecting water quality worldwide. This condition is caused by excessive nutrient inputs to aquatic systems, and one of the main consequences is accelerated phytoplankton growth. Eutrophication can lead to damage to human health, the environment, society, and the economy. One of the most serious consequences of eutrophication is the proliferation of cyanobacteria that can release toxins into the water. The aim of this research was to evaluate the trophic condition of a tropical reservoir over the course of time, using a database extending over 15 years to investigate relationships with environmental conditions, considering spatial heterogeneity and seasonality, as well as inter-relations between trophic state indicators. Data for chlorophyll-a, total phosphorus, and total nitrogen were collected from 2000 to 2014, and cyanobacteria abundance was determined from 2004 to 2014. The trophic state index was also calculated. The results demonstrated the existence of two distinct compartments in the reservoir: one lotic and the other lentic. No relationship was observed between chlorophyll-a and phosphorus. The results suggested that phytoplankton growth was mainly controlled by nitrogen concentrations. These conditions favored cyanobacteria predominance, resulting in increasing abundance of these potentially toxic bacteria over time. The model obtained indicated hypereutrophic conditions, with high phytoplankton biomass and cyanobacteria abundance during the next years likely to affect the uses of the water of the reservoir. (AU)

• FAPESP's process: 14/22581-8 - The European Union's Water Framework Directive: applications to Brazilian reservoirs reality
• Grantee: Marcelo Luiz Martins Pompêo
• Support Opportunities: Regular Research Grants
• FAPESP's process: 13/03494-4 - The reservoirs of the Cantareira System (Brazil, São Paulo): the relations between bioindicators benthic organisms and the heavy metals contamination.
• Grantee: Frederico Guilherme de Souza Beghelli
• Support Opportunities: Scholarships in Brazil - Doctorate