Dinâmica do mesozooplâncton e produção secundária de copépodes em resposta a parâmetros físico-químicos e climáticos em dois períodos de amostragem (2005-2013;2022-2023) em um estuário impactado - RJ

Abstract

This study evaluated the abundance and secondary production of mesozooplankton, with emphasis on the copepod species Acartia tonsa and Temora turbinata, over two sampling periods (2005–2013 and 2022–2023) in the central channel of Guanabara Bay. Physicochemical parameters, seasonality (dry and rainy periods), and the influence of largescale climatic phenomena (El Niño and La Niña) were analyzed. Statistical analyses (nMDS and PERMANOVA) revealed that seasonality had a significant influence on the abundance and secondary productivity of mesozooplankton and the studied species, while climatic phenomena significantly affected only the productivity of T. turbinata. In the recent period (2022–2023), there was a marked increase in secondary production, especially for T. turbinata during the rainy season, when values exceeded 12 mg C m⁻³ d⁻¹ and annual values surpassed 4,000 mg C m⁻³ year⁻¹, while A. tonsa maintained more stable patterns. The results highlight the ecological differences between the species, with T. turbinata exhibiting a more opportunistic behavior and A. tonsa showing greater resilience. The high production observed in Guanabara bay reflects the influence of local hydrodynamics and nutrient input, emphasizing the role of zooplankton as a biological indicator. This study reinforces the importance of long-term time series for understanding zooplankton responses to environmental pressures and climate change, as well as supporting monitoring strategies in highly impacted coastal systems.