Water quality changes in floodplain lakes due to the Amazon River flood pulse: Lago Grande de Curuaí (Pará)

Abstract

Assurance of water quality for human consumption is essential for public health policies. In the Amazon floodplain, the seasonal water level variation causes periodic flooding of marginal areas that are usually used for settlements, agriculture and livestock. Therefore, the exchange of materials between the terrestrial and aquatic ecosystem affects the proportion of suspended and dissolved components in water and its physical-chemical characteristics, and consequently the quality of the water used by local people. Following this approach, the aim of this study is to evaluate changes in water quality in Lago Grande de Curuaí floodplain, Óbidos, Pará in response to the flood pulse, during one hydrological year from 2003 to 2004, based on water use classes (according to National Water Agency 357/2005 resolution) using chlorophyll-a and dissolved oxygen concentration as parameters and the eutrophication index. Ordinary kriging was applied to interpolate chlorophyll-a and dissolved oxygen and to predict values at non sampled locations. Each location was then classified according to water use acceptable parameters and to Carlson Trophic State Index modified by Toledo to map lake water classes and trophic status. The result showed that Lago Grande de Curuaí floodplain is a supereutrophic system, with levels of dissolved oxygen and chlorophyll-a not suitable for human supply during the receding water phase. These areas are located near the riverine communities, which can cause health problems due to the presence of potentially toxic algae. Therefore, monitoring water quality in Amazon lakes is essential to ensure the availability has appropriate quality for human and animal supplies.Keywords: Amazon várzea, chlorophyll-a, dissolved oxygen, eutrophication index, seasonality.Mudanças na qualidade da água nos lagos de planície de inundação em função do pulso de inundação do rio Amazonas: lago Grande de Curuaí, Pará ResumoA garantia da qualidade da água para consumo humano é essencial para as políticas de saúde pública. Na planície Amazônica a variação sazonal do nível de água provoca inundações periódicas das áreas marginais que são normalmente utilizadas para os assentamentos humanos, a agricultura e a pecuária. Portanto, a troca de materiais entre os ecossistemas terrestres e aquáticos afeta a proporção de componentes em suspensão e dissolvidos na água e suas características físico-químicas, o que, consequentemente, afeta a qualidade da água utilizada pela população local. Seguindo essa abordagem, o objetivo deste trabalho é avaliar as mudanças na qualidade da água na planície de inundação do lago Grande de Curuaí, Óbidos, Pará, em função do pulso de inundação, durante um ano hidrológico de 2003 a 2004, tendo por base tanto as classes de uso da água (de acordo com a Resolução nº 357/2005 da Agência Nacional de Água), usando como parâmetros tanto a concentração de clorofila-a e o oxigênio dissolvido, quanto o índice de eutrofização. Utilizou-se o método de krigagem para interpolar os dados de clorofila-a e de oxig...

Influence of seasonal variation on the hydro-biogeochemical characteristics of two upland lakes in the Southeastern Amazon, Brazil

“…In the latter, the continuous input of organic matter may increase the probability of anoxia in hypolimnion. Considering the higher TSI for Violão Lake, it is speculated that after a period of several years this lake may host significant quantities of phytoplankton, including algal bloom, under natural eutrophication conditions, as has been observed in other Amazon lakes (Affonso et al 2011, Alves et al 2012. Besides nutrients, water pH is significantly different between lakes (Figure 4), which can be linked with phytoplankton growth (Hansen 2002, Wang et al 2011).…”

“…However, assessing phytoplankton growth is not as straightforward as it may occur as a result of the complex interplay between nutrient availability, light conditions, temperature, water residence time and flow conditions (Jeppesen et al 2005). Moreover, increasing phytoplankton growth can lead to serious ecological problems, such as eutrophication, and can also be a potential source of contamination of lake water because of the toxins produced by cyanobacteria which impair the ability to maintain aquatic life (Affonso et al 2011). Therefore, understanding the factors involved in water quality monitoring is vital to managing water resources.…”

“…In Brazil, the water quality information for many hydrographical basins is still limited or in some cases does not exist (ANA 2005). Furthermore, most investigations were undertaken on floodplain lakes and reservoirs (Molisani et al 2010, Affonso et al 2011, while studies on tropical upland lakes are scanty. This is particularly true for the closed-basin lake systems of the Amazonia region where knowledge of biota and driving forces acting on them is limited (Lopes et al 2011).…”

Ecology and seasonal variation of parasites in wild Aequidens tetramerus, a Cichlidae from the Amazon

“…In the Amazon, seasonal variation in water level is influenced mainly by seasonal rains in the Andinean region, cause of periodic flooding of marginal areas. The exchange of materials between terrestrial and aquatic ecosystems affects the proportion of suspended and dissolved material and the physical-chemical characteristics of the water bodies (Affonso et al 2011). Therefore, it is important to determine the roles of different parasite species within a community, if their infection levels are constant and if environmental variations caused by the seasonal dry/rainy cycle influences the availability of intermediate host and can lead to consequent alterations in the recruitment processes of parasites species.…”

Biological and Physico-Chemical Evaluation of the Eutrophication Potential of a Highly Rated Temperate Water Body in South – Eastern Romania

“…The assurance of water quality for human consumption is essential for public health policies. The exchange of materials between the terrestrial and hydro-system affects the proportion of suspended and dissolved components in water and its physical-chemical characteristics and consequently the quality of the water used by local people (Affonso et al 2011). Figure 16.…”