Warm-phase ENSO events modulate the continental freshwater input and the trophic state of sediments in a large South American estuary

García-Rodríguez, Felipe; Brugnoli, Ernesto; Muñiz, Pablo; Venturini, Natalia; Burone, Letícia; Hutton, M.; Rodríguez, M.; Pita, Ana Laura; Kandratavicius, Noelia; Pérez, Laura; Verocai, José E.

doi:10.1071/mf13077

Cited by 38 publications

(20 citation statements)

References 35 publications

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“…Moreover, the São Gonçalo channel has a gentle slope [8], which contributes to the low water flux towards the Patos lagoon and the increase in the Mirim lagoon water levels. Oliveira et al [12] suggested that freshwater inputs for the Mirim lagoon are influenced by ENSO events, increasing the precipitation in the region [31,32]. The ENSO influence on the Mirim lagoon was also observed by [25].…”

Section: Resultsmentioning

confidence: 85%

Relationships between Wind Effect, Hydrodynamics and Water Level in the World’s Largest Coastal Lagoonal System

Oliveira

Fernandes

Möller

et al. 2019

Water

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The Patos-Mirim is the largest coastal limnological system of the world, located in southern Brazil and eastern Uruguay, which encompass over 500 km of coastline. The economical demand for the development of an international waterway brings the need for understanding the Mirim lagoon dynamics and ulterior discharge into Patos lagoon in view of establishing navigation conditions and sustainable development. In this sense, circulation and freshwater discharge dynamics were assessed by running the numerical model TELEMAC-3D for a one-year-long simulation. The model identified the wind direction and intensity as the main combined forcing modulating water circulation and transport between the northern and southern portions and conditioning the recirculation cell orientation. Predominant winds from the S-SW directions could generate adverse conditions for navigation because they would yield low water levels under northwards water transport, thus creating shallow regions for navigation. Under such conditions, the high freshwater discharge coming from the Mirim lagoon would be restricted, and the communication to the Patos lagoon would be sufficiently weakened to prevent navigation activities. Therefore, we recommend that the viability of planning and implementing an international waterway, involving the two countries (Brazil and Uruguay), must take into account wind conditions prior to setting navigation traffic and avoid economic losses.

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Section: Resultsmentioning

confidence: 85%

Relationships between Wind Effect, Hydrodynamics and Water Level in the World’s Largest Coastal Lagoonal System

Oliveira

Fernandes

Möller

et al. 2019

Water

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“…In total, 36 water samples were analysed. The system presents strong temporal and spatial gradients in terms of temperature, conductivity (which was used as a proxy of salinity) and turbidity (Acha et al, 2008;Ferrari et al, 2011;García-Rodríguez et al, 2013;Kruk et al, 2015;Martínez de la Escalera et al, 2017). The highest surface water temperatures in Salto Grande reservoir are usually recorded during summer (January to March, 19-33 °C) while the lowest temperatures belong to the outer marine zone of the Río de la Plata during winter-early spring (June to October, 11-18 °C) Martínez de la Escalera et al, 2017).…”

Section: Study Sitementioning

confidence: 99%

Genotyping and functional regression trees reveals environmental preferences of toxic cyanobacteria (Microcystis aeruginosacomplex) along a wide spatial gradient

Escalera

Segura

Kruk

et al. 2019

Preprint

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Addressing ecological and evolutionary processes explaining biodiversity patterns is essential to identify the mechanisms driving community assembly. In the case of bacteria, the formation of new ecologically distinct populations or ecotypes is proposed as one of the main drivers of diversification. New ecotypes arise when mutation in key functional genes or acquisition of new metabolic pathways by horizontal gene transfer allow the population to exploit new resources, making possible their coexistence with parental population. Recently, we have reported the presence of toxic, microcystin-producing organisms from the Microcystis aeruginosa complex (MAC) through a wide environmental gradient (800 km) in South America, ranging from freshwater to estuarine-marine waters. In order to explain this finding, we hypothesize that the success of toxic organisms of MAC in such array of environmental conditions is due to the existence of ecotypes having different environmental preferences. So, we analysed the genetic diversity of microcystin-producing populations of Microcystis aeruginosa complex (MAC) by qPCR and high resolution melting analysis (HRMA) of a functional gene (mcyJ, involved in microcystin synthesis) and explored its relationship with the environmental conditions through the gradient by functional classification and regression trees (fCART). Six groups of mcyJ genotypes were distinguished and selected by different combinations of water temperature, conductivity and turbidity, determining the environmental preferences of each group. Since these groups were based on the basis of similar sequence and ecological characteristics they were defined as ecotypes of toxic MAC. Taking into account that the role of microcystins in MAC biology and ecology has not yet been elucidated, we propose that the toxin might have a role in MAC fitness that would be mainly controlled by the physical environment in a way such that the ecotypes that thrive in the riverine zone of the gradient would be more stable and less influenced by salinity fluctuations than those living at the marine limit of the estuary. These would periodically disappear or being eliminated by salinity increases, depending on the estuary dynamics. Thus, ecotypes generation would be an important mechanism allowing toxic MAC adapting to and succeed in a wide array of environmental conditions.

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“…However, it is still extremely difficult to predict the intensity and scale of these changes and the response of biological communities and changes in ecosystem functioning. Temperature and rainfall anomalies, as well as sea level rise, have been commonly reported across the globe and these effects may have substantial impacts on estuarine ecosystems over both the short-and long-term (ALONGI, 2008;DAY et al, 2008;CONDIE et al, 2012;TURRA et al, 2013;GARCÍA-RODRIGUEZ ET AL., 2014). For example, if regional and local rainfall anomalies and sea level changes alter the salt balance of an estuary, it might cause changes in species distribution and productivity (THURMAN et al, 2010;CONDIE et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

Benthic estuarine communities in Brazil: moving forward to long term studies to assess climate change impacts

et al. 2016

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Estuaries are unique coastal ecosystems that sustain and provide essential ecological services for mankind. Estuarine ecosystems include a variety of habitats with their own sediment-fauna dynamics, all of them globally undergoing alteration or threatened by human activities. Mangrove forests, saltmarshes, tidal flats and other confined estuarine systems are under increasing stress due to human activities leading to habitat and species loss. Combined changes in estuarine hydromorphology and in climate pose severe threats to estuarine ecosystems on a global scale. The ReBentos network is the first integrated attempt in Brazil to monitor estuarine changes in the long term to detect and assess the effects of global warming. This paper is an initial effort of ReBentos to review current knowledge on benthic estuarine ecology in Brazil. We herein present and synthesize all published work on Brazilian estuaries that has focused on the description of benthic communities and related ecological processes. We then use current data on Brazilian estuaries and present recommendations for future studies to address climate change effects, suggesting trends for possible future research and stressing the need for long-term datasets and international partnerships. AbstrActDescriptors: Estuaries, Benthic ecology, Climate change, Brazil, Impacts Estuários são ecossistemas costeiros que sustentam uma ampla variedade de serviços ambientais para a humanidade. Estuários abrigam muitos ambientes bentônicos com características específicas e seriamente ameaçados globalmente. Manguezais, marismas e planícies de maré são amplamente impactados por poluentes domésticos e industriais, por atividades comerciais que levam à perda de habitat e pela sobrepesca. Os diversos impactos locais, associados a mudanças regionais e globais na hidromorfologia estuarina e potenciais efeitos de mudanças climáticas, colocam sérias ameaças a ecossistemas estuarinos. A rede Bentos foi criada para estudar o efeito de mudanças no clima em ecossistemas bentônicos costeiros brasileiros. Este trabalho faz parte dos esforços iniciais do Grupo de Trabalho Estuários em rever o conhecimento sobre comunidades bentônicas estuarinas no Brasil. Aqui apresentamos uma breve revisão crítica sobre os trabalhos realizados objetivando o estudo, em nível de comunidades, do bentos estuarino e processos ecológicos associados. A partir do cenário atual, realizamos recomendações de estudo para responder questões científicas sobre efeitos de mudanças climáticas em comunidades bentônicas estuarinas, e enfatizamos a necessidade de bases de dados contínuas e de longa duração e o estabelecimento de parcerias internacionais com foco específico nos estuários brasileiros.

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Warm-phase ENSO events modulate the continental freshwater input and the trophic state of sediments in a large South American estuary

Cited by 38 publications

References 35 publications

Relationships between Wind Effect, Hydrodynamics and Water Level in the World’s Largest Coastal Lagoonal System

Relationships between Wind Effect, Hydrodynamics and Water Level in the World’s Largest Coastal Lagoonal System

Genotyping and functional regression trees reveals environmental preferences of toxic cyanobacteria (Microcystis aeruginosacomplex) along a wide spatial gradient

Benthic estuarine communities in Brazil: moving forward to long term studies to assess climate change impacts

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