Effects of Extreme Climatic Events on the Hydrological Parameters of the Estuarine Waters of the Amazon Coast

Costa, Ádila Kelly Rodrigues da; Pereira, Luci Cajueiro Carneiro; Jiménez, José A.; Oliveira, Antonio Rafael Gomes de; Flores‐Montes, Manuel; Costa, Rauquı́rio Marinho da

doi:10.1007/s12237-022-01056-y

Cited by 10 publications

(3 citation statements)

References 73 publications

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“…The current results show a high number of stranding events for Guiana dolphins in the BRNO region, indicating a high mortality rate for the species in this region. This high mortality rate was suggested by Emin‐Lima et al (2010) in a preliminary study on the Amazon Estuary and seems to persist over more recent years, indicating a high abundance of the species in this ecosystem and a constant exposure to anthropogenic and local environmental pressures, such as changes in the ecosystem condition (e.g., da Costa et al, 2022), fishing activity (e.g., Freire et al, 2021), increasing shipping traffic and tourism (e.g., Pereira et al, 2018) and coastal environmental degradation (e.g., Barletta & Lima, 2019; Lima et al, 2021).…”

Section: Discussionsupporting

confidence: 58%

Ups and downs: An insight on the stranding pattern of Guiana dolphins, Sotalia guianensis, in the Amazon Estuary, Northern Brazil

Ruenes,

Costa,

Laeta

et al. 2024

Aquatic Conservation

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Long‐term systematic records of cetacean strandings are valuable indicators of temporal responses of specific cetacean populations and communities to natural or anthropogenic pressures. They also help guide management objectives and conservation actions. Generalized additive models (GAMs) were used to analyse 10 years of systematic and opportunistic surveys of Guiana dolphin strandings in the Amazon Estuary region, Northern Brazil. The spatial distribution of strandings was assessed through kernel density maps, and age‐at‐death structure of this population was described. The model results revealed marked seasonality in the strandings and, by extension, the mortality of Guiana dolphins in the Amazon Estuary. This seasonality varied between the inner estuarine regions and Atlantic coastal area, reflecting the environment's characteristics. Long‐term decline of strandings in the Amazon Estuary inner region and unusual high mortality of young sexually mature individuals were detected. These results, besides the high stranding rate detected for the species, are mostly attributed to the species' interaction with intense fishing activity in the region. Conservation efforts should consider the seasonality of Guiana dolphin strandings in the Amazon Estuary. The systematic monitoring of strandings, especially in high‐frequency areas, is recommended for assessing long‐term species mortality. Additionally, implementing management actions related to the species' interaction with fishing activities, such as regulatory enhancements, gillnet modifications and seasonal no‐fishing zones, is advised. Educational campaigns targeting fishermen and riverine communities are essential to reduce bycatch and the folkloric use of the species. This study underscores the effectiveness of stranding data as a source of biological and ecological information, and as a tool for understanding human actions affecting coastal populations of aquatic mammals. It emphasizes the need for urgent studies to characterize this population, clarify the influence of bycatch as an anthropogenic pressure and implement effective conservation actions to preserve the Guiana dolphin population.

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Section: Discussionsupporting

confidence: 58%

Ups and downs: An insight on the stranding pattern of Guiana dolphins, Sotalia guianensis, in the Amazon Estuary, Northern Brazil

Ruenes,

Costa,

Laeta

et al. 2024

Aquatic Conservation

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“…As concentrações de clorofila-a, utilizadas como medida indireta da biomassa fitoplanctônica, apresentaram os maiores valores durante o período chuvoso, fenômeno este recorrente para a região costeira amazônica, sendo associado ao aumento das concentrações de nutrientes oriundos da drenagem continental e lixiviação das áreas de manguezais do entorno (Sousa et al, 2009;Pereira et al, 2010;Matos, et al, 2016ª, 2016bCosta et al, 2022). Outro fator que contribui para o aumento das concentrações de clorofila-a neste período, estaria relacionado a clorofila-a detrital alóctone (Lorenzen, 1967), uma vez que resíduos vegetais adjacentes costumam ser carreados para o estuário durante este período (Paiva et al, 2006).…”

Section: Análise De Correspondência Canônica (Acc)unclassified

Fitoplâncton do estuário do Emboraí Velho (Nova Olinda - PA)

Neto¹,

Costa²,

Silva³

et al. 2023

OLEL

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Este estudo avaliou o efeito da sazonalidade sobre as características hidrológicas e a dinâmica do fitoplâncton no estuário do Emboraí Velho. Foram realizadas coletas nictimerais em duas estações fixas durante marés de sizígia em quatro meses de 2018. As variáveis hidrológicas foram determinadas através de CTDO’s e da análise de amostras de água coletadas com garrafas de Niskin. O fitoplâncton foi coletado com redes cônicas de plâncton (64 µm) e com garrafas de Niskin (estudo quantitativo). Os resultados mostraram variações sazonais nas variáveis hidrológicas. Foram identificados 189 táxons, sendo as diatomáceas as mais abundantes e frequentes. A densidade fitoplanctônica e a biomassa (clorofila-a) variaram sazonalmente, com valores mais elevados no período seco e chuvoso, respectivamente. A análise de correspondência canônica (ACC) mostrou a existência de dois grupos sazonais distintos, demostrando a influência da pluviosidade sobre a hidrodrologia e a dinâmica da comunidade fitoplanctônica local.

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“…These processes may result in variations in the trophic status and salinity of the estuary, as observed at a number of locations, worldwide (Garcia-Rodriguez et al, 2013; Thompson et al, 2015). In the Amazon region, drought events make estuarine waters more saline, and result in a reduction in dissolved nutrient and chlorophyll a concentrations (Pereira et al, 2017;Costa et al, 2022;Oliveira et al, 2023;Procopio et al, 2024), whereas during periods of abnormally high rainfall, salinity declines, and the water becomes richer in dissolved inorganic nutrients and phytoplankton biomass (Pereira et al, 2013;Andrade et al, 2016).…”

Section: Introductionmentioning

confidence: 99%

Effects of climate events on the trophic status of an Amazonian estuary

Monteiro,

Pereira,

Costa

2024

Preprint

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In recent years, climate events such as Drought, El Niño, and La Niña have become increasingly frequent and more intense. Oceanographic monitoring was used to collect hydrological data in the middle and lower sectors of the Caeté estuary in different years. Negative rainfall anomalies of up to 45% were recorded during periods marked by Drought and El Niño events, which make the water of the Caeté estuary more saline and alkaline. During these events, the retention of dissolved inorganic nutrients in the middle sector appear to support increased eutrophication and more productive waters, whereas moderate eutrophication and lower productivity were observed in the lower sector. During the La Niña events, by contrast, positive rainfall anomalies may reach 60%, resulting in more oxygenated water in the estuary. In addition, the lower sector tends to more eutrophic during periods of high rainfall and freshwater discharge, as observed in this study during a La Niña event. The paucity of data on the effects of extreme climate events in Amazonian environments means that the findings of the present study may provide a useful model for the assessment of the effects of these events on other natural environments in the Amazon region.

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Effects of Extreme Climatic Events on the Hydrological Parameters of the Estuarine Waters of the Amazon Coast

Cited by 10 publications

References 73 publications

Ups and downs: An insight on the stranding pattern of Guiana dolphins, Sotalia guianensis, in the Amazon Estuary, Northern Brazil

Ups and downs: An insight on the stranding pattern of Guiana dolphins, Sotalia guianensis, in the Amazon Estuary, Northern Brazil

Fitoplâncton do estuário do Emboraí Velho (Nova Olinda - PA)

Effects of climate events on the trophic status of an Amazonian estuary

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