Acta Limnologica Brasiliensia
https://app.periodikos.com.br/journal/alb/article/doi/10.1590/S2179-975X11820
Acta Limnologica Brasiliensia
Original Article

Trophic assessment of four tropical reservoirs using phytoplankton genera

Avaliação trófica de quatro reservatórios tropicais usando gêneros fitoplanctônicos

Carlos A. Rivera; Angela Zapata; William Villamil; Nubia León-López

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Abstract

Abstract:: Aim: Monitoring the trophic state of reservoirs requires indices that provide a quick report of the ecosystem to decision makers. This study aimed to develop a system of trophic status indicators for tropical mountain reservoirs using phytoplankton genera.

Methods: Between 2004 and 2010, four reservoirs for water supply in Bogotá (Colombia), which have different trophic statuses and hydraulic management, were monitored. Samples were collected for the analysis of physical and chemical variables and phytoplankton community. Through multivariate analysis, the significance of the relationships between environmental variables and phytoplankton species and genera was established. Subsequently, trophic indices were proposed as relevant variables. The global trophic index was calculated as the sum of the partial indices.

Results: Analysis of the main components showed that reservoirs varied chemically depending on trophic status. Phytoplankton were composed of 63 genera, 59% of which were present in the four reservoirs. Although the physical characteristics of water, such as temperature and total solids content, explained a large part of the variation in the genera, a significant relationship between the genera and variables related to trophic state was observed in each reservoir. The multivariate analyses grouping the data by genera showed a behavior similar to the analysis using information at the species level. Plankton indices of trophic state were developed for phosphorus (TP), total Kjeldahl nitrogen (TKN), total organic carbon (TOC), and Secchi disk (SD) using data grouped by genera. The indices were significantly correlated with the values of each variable in each reservoir. Linear regression models showed a significant prediction of chlorophyll-a using TP, TKN, and SD indices in the three reservoirs with the highest trophic level. In addition, the global index showed a significant relationship with variables related to the trophic state.

Conclusions: Phytoplankton data at the genus level can be used to assess trophic status. The models for SD, TP, and TKN could be used as indicators of the trophic status of the studied reservoirs.

Keywords

trophic index, ecological optimum, ecological indicator, phytoplankton, eutrophication

Resumo

Resumo: : Objetivo: O monitoramento do estado trófico de reservatórios requer índices que forneçam um relatório rápido do ecossistema aos tomadores de decisão. Este estudo teve como objetivo desenvolver um sistema de indicadores de estado trófico para reservatórios de montanha tropical usando gêneros de fitoplâncton.

Métodos: Entre 2004 e 2010, foram monitorados quatro reservatórios para abastecimento de água em Bogotá (Colômbia), que apresentam diferentes estados tróficos e gestão hidráulica. Amostras foram coletadas para análise de variáveis ​​físicas e químicas e comunidade fitoplanctônica. Por meio de análise multivariada, estabeleceu-se a significância das relações entre variáveis ​​ambientais e espécies e gêneros fitoplanctônicos. Posteriormente, os índices tróficos foram propostos como variáveis ​​relevantes. O índice trófico global foi calculado como a soma dos índices parciais.

Resultados: A análise dos principais componentes mostrou que os reservatórios variam quimicamente dependendo do estado trófico. O fitoplâncton foi composto por 63 gêneros, 59% dos quais estavam presentes nos quatro reservatórios. Embora as características físicas da água, como temperatura e teor de sólidos totais, explicassem grande parte da variação dos gêneros, observou-se em cada reservatório uma relação significativa entre os gêneros e as variáveis ​​relacionadas ao estado trófico. As análises multivariadas agrupando os dados por gênero mostraram um comportamento semelhante à análise utilizando informações em nível de espécie. Os índices de estado trófico do plâncton foram desenvolvidos para fósforo (TP), nitrogênio Kjeldahl total (TKN), carbono orgânico total (TOC) e disco de Secchi (SD) usando dados agrupados por gêneros. Os índices foram significativamente correlacionados com os valores de cada variável em cada reservatório. Modelos de regressão linear mostraram um poder preditivo significativa de clorofila-a usando os índices TP, TKN e SD nos três reservatórios com maior nível trófico. Além disso, o índice global apresentou relação significativa com variáveis ​​relacionadas ao estado trófico.

Conclusões: Os dados do fitoplâncton em nível de gênero podem ser usados ​​para avaliar o estado trófico. Os modelos para SD, TP e TKN podem ser utilizados como indicadores do estado trófico dos reservatórios estudados.
 

Palavras-chave

índice trófico, ótimo ecológico, indicador ecológico, fitoplâncton, eutrofização

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Submitted date:
12/20/2020

Accepted date:
10/17/2022

Publication date:
11/03/2022

63640b7aa953954e30749203 alb Articles
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