The role of a cascade of reservoirs and seasonal variation in the phytoplankton structure in a tropical river

Moura, Ariadne do Nascimento; Severiano, Juliana Santos; Tavares, N K A; Dantas, Ênio Wocyli

doi:10.1590/s1519-69842013000200009

Cited by 22 publications

(13 citation statements)

References 25 publications

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“…Acta Limnologica Brasiliensia, 2017, vol. 29, e17 concentration, due to nutrient enrichment and abundant water flow (Moura et al, 2013). A similar relation to the increase in cell density associated with the retention time occurred in the Ernestina reservoir, when the highest densities near the spillway coincide with the longer water retention times in 436 days, from March to June, while the general average found was 198 days.…”

Section: Discussionmentioning

confidence: 52%

Climate factors and limnological conditions shaping phytoplankton community in two subtropical cascading reservoirs

et al. 2017

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Cite as: Cassol, A.P.V. et al. Climate factors and limnological conditions shaping phytoplankton community in two subtropical cascading reservoirs. Acta Limnologica Brasiliensia, 2017, vol. 29, e17. Abstract: Aim: A series of dams along the course of a river forms a complex cascading reservoir system. The interconnectivity of the dams is perceived with the reduction of turbidity and phosphorus and the increase of specific richness throughout the system. Designing a management system that promotes the integration of biotic and abiotic data is essential to these resources of recognized importance for the population, the country's power generation and watersheds management. The Jacuí River is an important water resource in the state of Rio Grande do Sul, along its upper course, five water reservoirs comprise a cascade system tapped for energy generation and agriculture, but the effects on the phytoplankton community of cascading dams are still unknown. Thus, the present study aimed to investigate spatial and temporal patterns of phytoplankton associated with climatological and limnological characteristics of the Ernestina and Itaúba water reservoirs, located in the upper Jacuí River, RS, Brazil. Methods: Sampling campaigns were carried out seasonally from January 2012 to February 2013, with four sampling stations within each dam and at three different depths. The sampling units were determined according to the three zones of the reservoir: river areas, transition and lake. Results: A total of 91 phytoplankton species were identified in Ernestina and 130 in Itaúba. There was no significant difference between vertical and horizontal patterns, since the community responded to seasonal changes and the specific characteristics of each dam. Conclusions: The specific richness and water transparency increased downstream of the system and changes in water retention time were important for cell density and composition.Keywords: Plankton; seasonality; ecological dynamics; retention time.Resumo: Objetivo: Uma série de represas ao longo do curso de um rio formam o complexo sistema em cascata de reservatórios. A interconectividade dessas represas são percebidas com a redução da turbidez e fósforo e aumento da riqueza de espécie ao longo do sistema. Além disso, cada reservatório possui suas características, bióticas e abióticas, que devem ser avaliadas e utilizadas como instrumento na elaboração de propostas de manejo contínuo das bacias hidrográficas. O rio Jacuí, com cinco represas inseridas ao longo do seu curso superior, é um importante recurso hídrico do estado do RS, explorado para geração de energia e agricultura, no entanto seus efeitos na comunidade fitoplanctônica das represas construídas em cascata ainda é desconhecido. Dessa forma o presente estudo teve como objetivo investigar padrões espaciais e temporais do fitoplâncton associadas às características climatológicas e 2 Cassol, A.P.V. et al.

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Section: Discussionmentioning

confidence: 52%

Climate factors and limnological conditions shaping phytoplankton community in two subtropical cascading reservoirs

et al. 2017

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“…In SN reservoir, Planktothrix agardhii was dominant during most of the sampling period but had very small representation in AM reservoir. Moura et al (2013) also found that Planktothrix agardhii was dominant in Funil reservoir during the rainy season, overwhelming the concentration of Cylindrospermopsis raciborskii. This may have serious implications for drinking water reservoirs.…”

Section: Discussionmentioning

confidence: 90%

Impact of filamentous cyanobacteria on the water quality of two tropical reservoirs

Barros

Lopes

Carvalho³

et al. 2017

RBRH

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Artificial lakes play an important role in water availability in tropical semi-arid Northeastern Brazil. However, in addition to the negative effects that dams have on the water quality of rivers, other practices such as discharge of untreated wastewater, intensive crop fertilization and fish farming have been contributing to water quality deterioration. Climate change may be another driver of water quality decrease. Increases in precipitation and drought intensities as well as temperature increase may redefine the dynamics of planktonic communities and favour species more adapted to the new environment. Water samples were collected in two reservoirs selected based on the recurrence of positive results for saxitoxins, Acarape do Meio (AM) and Sitios Novos (SN). In general, diversity in SN (1.08) was higher than in the AM (0.60). Phytoplankton dynamics in these reservoirs differ from other reservoirs in the same region of Brazil, in the sense that filamentous cyanobacteria are dominant. Furthermore, lower diversity, concentration and richness of chlorophyceae and bacillariophyceae were found in both reservoirs. Increase in diversity was observed during the intense rainy season of 2011, suggesting a slight improvement of water quality. A close inverse correlation between Cylindrospermopsis sp and other cyanobacteria was found in SN (R 2 = -0.862) and in AM (R 2 = -0.997) and the data collected demonstrates that a season with intensive rainfall may lead to lower cyanobacteria concentrations probably due to water dilution and higher flushing rates.Keywords: Artificial reservoirs; Freshwater cyanobacteria; Semi-arid regions; Temporal phytoplankton dynamics; Eutrophication. RESUMOOs lagos artificiais tem um papel primordial na disponibilidade hídrica no semi-árido Brasileiro. Entretanto, além dos efeitos negativos que os barramentos dos rios causam sobre a qualidade da água, a descarga de esgotos, a irrigação e a piscicultura intensivas vêm acentuando a deterioração da qualidade da água em um ritmo sem precedentes nesta região. A mudança climática é outro fator de impacto negativo na qualidade da água. O aumento da intensidade das precipitações pode redefinir a dinâmica das comunidades de plâncton e espécies mais adaptadas a ambientes extremamente variáveis. Os reservatórios estudados, Acarape do Meio (AM) e Sítios Novos (SN), foram selecionados com base na recorrência de resultados positivos para saxitoxinas. A dinâmicas do fitoplâncton encontrada, difere de outras áreas da mesma região, no sentido em que as cianobactérias filamentosas são dominantes. Baixas diversidade, concentração média e riqueza de Chlorophyceae e Bacillariophyceae foram encontrados em ambos os reservatórios, embora tenha sido observado um aumento durante o intenso período chuvoso de 2011, sugerindo uma ligeira melhoria da qualidade da água. Em geral, a diversidade no reservatório SN (1,08) foi maior que no AM (0,60). Uma correlação inversa entre a concentração de Cylindrospermopsis sp e outras cianobactérias foi encontrada nos reservatór...

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“…The effects of this daily fluctuation on river-reservoir systems are reported by Naliato et al (2009). The high current speed downstream from Itaipu Reservoir caused an intensive dilution of the potamoplankton which developed in lentic sites inside the reservoir, but an increase in richness and abundance can occur in relatively small rivers and downstream from reservoirs with very high water retention times (Moura et al 2013). Lentic stations in reservoirs with long water retention times are generally favorable for phytoplankton blooms composed of r-strategists (Silva et al 2005).…”

Section: Discussionmentioning

confidence: 99%

Changes in the phytoplankton structure downstream a large reservoir: effects of tributaries on the assemblages attributes

et al. 2015

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Changes in richness, diversity, evenness and abundance of phytoplankton in relation to environmental variables and tributary entrances were studied along 30 km of the Paraná River downstream Itaipu Reservoir. A high number of taxa was found, 315. The Paraná River differed from the tributaries Iguaçu River and Monday River. The phytoplankton and limnological characteristics of the Paraná River changed after the entrance of these tributaries. Higher values of richness and alpha diversity of phytoplankton were found in the two tributary rivers, which also produced an increase in the corresponding mean values in the Paraná River. Higher values of total abundance and lower values of evenness were found at the dam site with typical lentic conditions. The assemblages of the two tributary rivers were homogeneous. Bellow dam the phytoplankton exhibited a decrease in abundance and an increase in evenness. Water transparency, water flow, nutrients and turbidity were the main indicators of the system spatial heterogeneity. Several species were correlated with silicate, redox potential and/or water temperature. Reservoir conditions promote conspicuous differences in the phytoplankton of the Paraná River. The downstream reorganization of the community, with a sharp decrease in abundance, is positively influenced by tributary rivers in terms of richness and diversity.

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The role of a cascade of reservoirs and seasonal variation in the phytoplankton structure in a tropical river

Cited by 22 publications

References 25 publications

Climate factors and limnological conditions shaping phytoplankton community in two subtropical cascading reservoirs

Climate factors and limnological conditions shaping phytoplankton community in two subtropical cascading reservoirs

Impact of filamentous cyanobacteria on the water quality of two tropical reservoirs

Changes in the phytoplankton structure downstream a large reservoir: effects of tributaries on the assemblages attributes

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