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Bouvy, Marc; Nascimento, Silvia M.; Molica, Renato José Reis; Ferreira, Andrea Cristina da Silva; Huszar, Vera L. M.; Azevedo, Sandra M.F.O.

doi:10.1023/a:1025405817350

Cited by 122 publications

(36 citation statements)

References 35 publications

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“…Climate change to drier conditions alters the hydrological properties of individual lakes and may have consequences on the thermal structure and light regime that directly affect aquatic organisms (Carpenter et al, 1992;Bouvy et al, 2003). However, in this study it was found that an unusual precipitation, becoming a homogeneous dynamics of phytoplankton functional groups L 0 , S 1 and K, which are the most representative in both samplings campaigns.…”

Section: Discussioncontrasting

confidence: 54%

Diel dynamic of phytoplankton functional groups in a tropical water supply, Extremoz Lake, northeastern Brazil

Pinto

Becker

2014

Acta Limnol. Bras.

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Aim: This study analyzed -the diel and vertical dynamics of phytoplankton functional groups in a natural tropical lake (Extremoz Lake, northeast Brazil), to investigate and understand the driver factors of the community during a severe drought period. Methods: Sampling of the abiotic variables and phytoplankton was performed at intervals of 6 hours over 24 hours in vertical profiles, in dry and rainy seasons (according to the historical average). The phytoplankton species were grouped according to the functional groups' approach sensu Reynolds et al. (2002). Results: October/12 was considered as a dry period (18.4 mm), while March/13, due to the historical average, as a rainy season, due to the low rainfall during the study period (15.7 mm), it was called severe drought. The lake showed thermal and chemical destratification in both periods. Phytoplankton biomass was higher in the dry season and their vertical distribution was stratified in both periods. In both samplings there were less algal biomass during the night. Phytoplankton functional groups of mixed and shallow systems (S 1 , L 0 and K) were descriptors throughout the study period with higher biomass always registered in the group S 1 , represented by Planktolyngbya limnetica (Cyanobacteria) Conclusion: The lack of seasonality observed in this study, due to prolonged drought, may have influenced the pattern of homogeneous behavior in both samplings. This pattern strongly influenced the vertical distribution of phytoplankton in the two periods, with a constancy of dominance of functional descriptors groups.Keywords: shallow lake, vertical distribution, cyanobacteria, functional groups.Resumo: Objetivo: O nosso trabalho teve como objetivo avaliar a dinâmica nictemeral e vertical dos grupos funcionais fitoplanctônicos em uma lagoa natural tropical (Lagoa de Extremoz, nordeste do Brasil), para investigar e compreender os fatores direcionadores da comunidade em um período de seca severa. Métodos: As amostragens das variáveis abióticas e do fitoplâncton foram realizadas a intervalos de 6 horas ao longo de um ciclo de 24 horas em perfis verticais nas estações de seca e chuva. As espécies fitoplanctônicas foram agrupadas de acordo com a abordagem de grupos funcionais sensu Reynolds et al. (2002). Resultados: O mês de outubro/12 foi caracterizado como período seco (18,4 mm), enquanto que março/13, pela média histórica era caracterizado período chuvoso, devido a baixa precipitação no período de estudo (15,7 mm), foi denominado seca severa. A lagoa apresentou desestratificação térmica e química em ambos períodos. A biomassa do fitoplâncton foi maior na estação seca e a distribuição vertical da mesma foi estratificada em ambas os períodos. Em ambas as amostragens houve menor biomassa algal nos períodos noturnos. Grupos funcionais fitoplanctônicos típicos de ambientes rasos e misturados (S 1 , L 0 e K) foram descritores durante todo o período do estudo, com maior biomassa registrada sempre no grupo S 1 , representado pela Planktolyngbya limnetica (Cyanobac...

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Section: Discussioncontrasting

confidence: 54%

Diel dynamic of phytoplankton functional groups in a tropical water supply, Extremoz Lake, northeastern Brazil

Pinto

Becker

2014

Acta Limnol. Bras.

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“…Understanding of the regulation of NEP due to climate changes is critical to understand whether or not the sediments will store or process organic matter. This issue should be addressed in future studies, to improve understanding of this dynamic in tropical areas, taking into account that: (1) the combination of high temperatures over the year and low average watercolumn depths will increase the homogenization of the water column and its connection with the sediment; and (2) seasonal precipitation and floodplain dynamics regulate the inputs of water, organic matter and nutrients into aquatic ecosystems, thus regulating NEP-related processes (Apple et al, 2006;Biddanda and Cotner, 2002;Thomaz et al, 2007).The sediment is the main nutrient and organic-matter storage compartment in lakes and wetlands, and therefore is known as a long-term carbon trap in aquatic ecosystems (Tranvik et al, 2009). As most of the lakes on Earth are small and shallow, with low volume:area ratios, the metabolism of the sediment compartment is considered extremely important for the overall aquatic metabolism (Downing et al, 2006).…”

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confidence: 99%

Climate change in Brazil: perspective on the biogeochemistry of inland waters

Roland

Huszar

et al. 2012

Braz. J. Biol.

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Although only a small amount of the Earth's water exists as continental surface water bodies, this compartment plays an important role in the biogeochemical cycles connecting the land to the atmosphere. The territory of Brazil encompasses a dense river net and enormous number of shallow lakes. Human actions have been heavily influenced by the inland waters across the country. Both biodiversity and processes in the water are strongly driven by seasonal fluvial forces and/or precipitation. These macro drivers are sensitive to climate changes. In addition to their crucial importance to humans, inland waters are extremely rich ecosystems, harboring high biodiversity, promoting landscape equilibrium (connecting ecosystems, maintaining animal and plant flows in the landscape, and transferring mass, nutrients and inocula), and controlling regional climates through hydrological-cycle feedback. In this contribution, we describe the aquatic ecological responses to climate change in a conceptual perspective, and we then analyze the possible climate-change scenarios in different regions in Brazil. We also indentify some potential biogeochemical signals in running waters, natural lakes and man-made impoundments. The possible future changes in climate and aquatic ecosystems in Brazil are highly uncertain. Inland waters are pressured by local environmental changes because of land uses, landscape fragmentation, damming and diversion of water bodies, urbanization, wastewater load, and level of pollutants can alter biogeochemical patterns in inland waters over a shorter term than can climate changes. In fact, many intense environmental changes may enhance the effects of changes in climate. Therefore, the maintenance of key elements within the landscape and avoiding extreme perturbation in the systems are urgent to maintain the sustainability of Brazilian inland waters, in order to prevent more catastrophic future events.

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“…The characteristics of light intensity, water temperature, nutrient availability and turbidity may be altered owing to rainfall pattern in certain regions of the world, consequently modifying the phytoplankton production and biomass in a wide range of aquatic ecosystems (Reynolds, 2000;Scheffer, 2004). The El Niño effect and its impact on phytoplankton community composition have been well documented in freshwaters of tropical and subtropical regions of Brazil and Argentina of the Southern hemisphere through cycle of drought polygon and unusual rain fall (Bouvy et al, 2003;Devercelli, 2010).…”

Section: Introductionmentioning

confidence: 67%

Morphofunctional changes of phytoplankton community during pluvial anomaly in a tropical reservoir

et al. 2015

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The present study focuses on the structure and function of phytoplankton community during periods of marked changes in hydrological traits, influenced by an atypical climatic event (La Niña) and its impact on Armando Ribeiro Gonçalves Reservoir of Rio Grande do Norte, situated in the Caatinga biome of northeastern Brazil. The main questions addressed were: What are the effects of environmental factors on the temporal variation of Morphologically Based Functional Group (MBFG) of phytoplankton community? How does the composition of cyanobacterial species shift in relation to high and low trends of phytoplankton diversity? The samples were collected monthly during 2008-2009 and analyzed for pH, temperature, electrical conductivity, dissolved oxygen content and the nutrients, such as, nitrate-nitrogen, ammoniacal nitrogen, total nitrogen and orthophosphate. Phytoplankton samples were collected for both qualitative and quantitative analyses to evaluate species richness index and species diversity index. The data was divided into two distinct hydrodynamic periods of instability and stability. The results demonstrate considerable changes in dissolved oxygen content, water transparency and nitrogen nutrients, which directly influenced the MBFG of phytoplankton community in space and time. The instability of reservoir water was caused by heavy rainfall, which exerts atypical external disturbances. The seasonal variation of MBFG demonstrates a change in cyanobacterial composition and their diversity during instability and stability periods. MBFG VII, composed by colonial cyanobacteria with mucilage, was associated with reduced values of electrical conductance and alterations in pH. The predominance of filamentous species with heterocyst (MBFG III) occurs only during the hydrodynamic stability period and did not show significant association with analyzed parameters. The co-dominance of MBGFs III, V and VII along with high species diversity of phytoplankton community occurred during the second hydrodynamic instability period which was associated with the reduction in water temperature. It is concluded that the decrease in cyanobacterial species dominance and the general increase in the diversity of phytoplankton community are influenced by pluvial anomaly. The higher water level during the period of pluvial anomaly resulted in nutrient pulse and the mixing of water column in the reservoir, which determined the MBPG phytoplankton community distribution.Keywords: hydrodynamism, environmental factors, phytoplankton community, morphofunctional groups. Alterações morfofuncionais da comunidade fitoplanctônica durante anomalia pluvial em um reservatório tropicalResumo O presente estudo centra-se na estrutura e função da comunidade fitoplanctônica nos períodos de alterações marcantes nas características hidrológicas, influenciado por um evento climático atípico (La Niña) e seu impacto sobre o Reservatório: Armando Ribeiro Gonçalves, no Rio Grande do Norte, situado no bioma Caatinga, localizado na Região Nordeste do Brasil. ...

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Untitled

Cited by 122 publications

References 35 publications

Diel dynamic of phytoplankton functional groups in a tropical water supply, Extremoz Lake, northeastern Brazil

Diel dynamic of phytoplankton functional groups in a tropical water supply, Extremoz Lake, northeastern Brazil

Climate change in Brazil: perspective on the biogeochemistry of inland waters

Morphofunctional changes of phytoplankton community during pluvial anomaly in a tropical reservoir

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