El Niño Southern Oscillations and Pacific Decadal Oscillation as drivers of the decadal dynamics of benthic macrofauna in two subtropical estuaries (South Brazil)
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Data
2019
Tipo de documento
Dissertação
Título da Revista
ISSN da Revista
Título de Volume
Área do conhecimento
Engenharias
Modalidade de acesso
Acesso aberto
Editora
Autores
Francisco, André Silva
Orientador
Netto, Sérgio Antonio
Coorientador
Resumo
O El Niño- Oscilação Sul (ENSO) e a Oscilação Decadal do Pacífico (PDO) são oscilações climáticas em grande escala que afetam as teleconexões atmosféricas e oceânicas e desencadeiam eventos meteorológicos em diferentes escalas temporais e espaciais, tanto em áreas tropicais como extratropicais. Ao longo de 11 anos (2007 a 2017), a influência dos ENSO eventos (El Niño, La Niña e neutro) e diversidade (canônico e Modoki) e do PDO (fases positiva e negativa) sobre variáveis meteorológicas e invertebrados macrobênticos foi analisada em dois tipos de estuários subtropicais do sul do Brasil. Apesar de sua proximidade geográfica (85 km de distância), os estuários exibiram nítidas diferenças meteorológicas determinadas por processos orográficos, embora ambos tenham sido afetados pelo PDO e ENSO. A macrofauna bêntica dos estuários, um dominado por maré e outro dominado por rio, foi claramente distinta com maior riqueza de espécies no primeiro. A variabilidade de longo prazo da macrofauna bêntica em ambos os estuários foi fortemente influenciada pela oscilação decadal da temperatura da superfície do mar do Pacífico (PDO) e ENSO. Entretanto os sinais do PDO e ENSO diferiram entre os estuários estudados. O estuário dominado por maré foi primeiramente influenciado pelo PDO, e apenas secundariamente pelo ENSO. Já o estuário do dominado por rio exibiu comportamento oposto, com eventos ENSO como principal força moduladora da variabilidade decadal dos invertebrados macrobênticos. Os resultados também mostraram ainda que PDO e ENSO possuem efeitos combinados para ambos estuários, com maiores dissimilaridades da macrofauna durante períodos construtivos (PDO Positivo/EL Niño vs PDO Negativo /La Niña).
The El Niño-Southern Oscillation (ENSO) and the Pacific Decadal Oscillation (PDO) are large-scale climatic phenomena affecting atmospheric and oceanic teleconnections, and thus triggering weather events at different temporal and spatial scales, both in tropical and extratropical areas. During 11 years (2007 to 2017), the influence of ENSO events (El Niño, La Niña and Neutral), ENSO diversity (canonical and Modoki) and PDO (positive and negative phases) on meteorological conditions and macrobenthic invertebrates were analyzed in two distinct (tide-dominated and river-dominated) subtropical estuaries of southern Brazil. Despite their geographical proximity (only 85 km apart), and although both were affected by the PDO and ENSO, the estuaries exhibited clear meteorological differences determined by orographic processes. The benthic estuarine macrofauna was clearly distinct and with higher species richness in the tide-dominated estuary. The long-term variability of benthic macrofauna in both estuaries was strongly influenced by the PDO and ENSO events. However, the signs of PDO and ENSO effects differed between the studied estuaries. The tide-dominated estuary was primarily influenced by the PDO, and only secondarily by the ENSO. On the other hand, the river-dominated estuary showed an opposite behavior, with ENSO events as the main modulating force of decadal variability of macrobenthic invertebrate community. Our results also showed that PDO and ENSO events have combined effects on both estuaries, with higher macrofauna dissimilarities during constructive periods (PDO Positive/EL Niño vs. PDO Negative/La Niña).
The El Niño-Southern Oscillation (ENSO) and the Pacific Decadal Oscillation (PDO) are large-scale climatic phenomena affecting atmospheric and oceanic teleconnections, and thus triggering weather events at different temporal and spatial scales, both in tropical and extratropical areas. During 11 years (2007 to 2017), the influence of ENSO events (El Niño, La Niña and Neutral), ENSO diversity (canonical and Modoki) and PDO (positive and negative phases) on meteorological conditions and macrobenthic invertebrates were analyzed in two distinct (tide-dominated and river-dominated) subtropical estuaries of southern Brazil. Despite their geographical proximity (only 85 km apart), and although both were affected by the PDO and ENSO, the estuaries exhibited clear meteorological differences determined by orographic processes. The benthic estuarine macrofauna was clearly distinct and with higher species richness in the tide-dominated estuary. The long-term variability of benthic macrofauna in both estuaries was strongly influenced by the PDO and ENSO events. However, the signs of PDO and ENSO effects differed between the studied estuaries. The tide-dominated estuary was primarily influenced by the PDO, and only secondarily by the ENSO. On the other hand, the river-dominated estuary showed an opposite behavior, with ENSO events as the main modulating force of decadal variability of macrobenthic invertebrate community. Our results also showed that PDO and ENSO events have combined effects on both estuaries, with higher macrofauna dissimilarities during constructive periods (PDO Positive/EL Niño vs. PDO Negative/La Niña).
Palavras-chave
Long-term variability, Estuarine communities, Climate variability, Benthic biodiversity, Coastal environment