Tidal variability of water quality parameters in a mesotidal estuary (Sado Estuary, Portugal)

Nascimento, Armiliana Soares; Biguino, Beatriz; Borges, Carlos; Cereja, Rui; Cruz, Joana; Sousa, Fátima; Dias, Joaquim; Brotas, Vanda; Palma, Carla; Brito, Ana C.

doi:10.1038/s41598-021-02603-6

Cited by 29 publications

(17 citation statements)

References 54 publications

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“…The phytoplankton dynamics in the Sado Estuary were characterized by several spatial differences. Chlorophyll a concentration was always higher upstream (maximum of 12 mg m −3 ) than in the middle and outer regions, a pattern that is in accordance with most of the studies conducted in the Sado Estuary 9 , 17 , 27 , 42 , as well as in other temperate estuarine systems 23 , 25 , 43 , 44 . However, higher Chl a concentration can occur at the Alcácer channel, as observed in a previous study (25 mg m −3 average in the 1990’s 22 ).…”

Section: Discussionsupporting

confidence: 88%

“…1 ): (i) one station located upstream near the Alcácer channel (AC), WB5; (ii) one located northward, in the Marateca channel (MC), WB6; (iii) one in the middle estuarine region (MR), WB5; and (iv) one in the downstream area, near the estuary mouth (EM), WB1. Stations EM and MR in this study correspond, respectively, to stations A and D in a previous study performed in this estuary during the same period, focused on the effect of the tidal variability in the water quality parameters 27 .…”

Section: Methodsmentioning

confidence: 88%

“…The circulation in this estuary occurs through two navigation channels (North and South Channels), with the South channel being the main route for water exchange 15 . The oceanic water influences the entire Sado Estuary, with high salinity values observed throughout the whole estuary, reaching values near 35 during summer in the innermost regions 26 , and with upwelling influencing phytoplankton biomass especially near the estuary mouth 27 , 28 .

Figure 1 Map of the study area, Sado Estuary, with the location (black dots) and identification of each study site: AC—Alcácer channel, MC—Marateca channel, MR—middle region, and EM—estuary mouth.…”

Section: Methodsmentioning

confidence: 99%

“…Water temperature (ºC) and DO were measured in situ using two multiparameter sondes (Hydrolab DS4a and DS5X, from OTT Hydromet), while salinity, pH and nutrient concentrations (µmol L −1 ) were measured in the laboratory using, respectively, a high precision Guildline Autosal8400B salinometer, a calibrated Metrohm benchtop 744 pH meter, and a Skalar SANplus autoanalyzer specially engineered for the analysis of saline waters by UV/Vis spectrometry. Further details on the methodologies used are described in Nascimento et al 27 . Turbidity was also measured in the laboratory by the nephelometric method using a portable infrared Lovibond TB 210IR turbidity meter, following the methodology described in Sent et al 26 .…”

Section: Methodsmentioning

confidence: 99%

“…To analyze the chlorophyll a (Chl- a ) concentration, ca. 1 L of water samples collected at surface were filtered, extracted by a mixture of Acetone:Water 9:1 (v:v) and analyzed in the laboratory using a ThermoFisher Scientific Evolution 201 spectrophotometer, according to Nascimento et al 27 . The absorbance was read using a spectrophotometer (UV–VIS Unicam UV2-100 and ThermoScientific Evolution201) at 664 nm to determine Chl- a content.…”

Section: Methodsmentioning

confidence: 99%

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Spatio-temporal dynamics of phytoplankton community in a well-mixed temperate estuary (Sado Estuary, Portugal)

Santos

Amorim

Brotas

et al. 2022

Sci Rep

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Estuaries are highly productive ecosystems, which are strongly affected by several anthropogenic pressures. Phytoplankton is a key element for assessing the ecological quality status in these transitional waters. Moreover, understanding physico-chemical and biological drivers is crucial to disentangle their effect on the structure of phytoplankton community. The present work aims to study the effect of the main physico-chemical drivers on the phytoplankton community structure and dynamics in a temperate well-mixed estuary (Sado Estuary). Four sampling stations were analyzed monthly in three regions of the estuary, from 2018 to 2019. Surface water samples were collected to analyze the phytoplankton community and several concomitant physico-chemical parameters. Temperature, turbidity, salinity, and nutrients availability were the drivers that best explained the spatio-temporal patterns observed in the phytoplankton community. The upper estuary was characterized by higher phytoplankton cell abundances and biomass. Three phytoplankton groups stood out in the characterization of the estuarine assemblages: diatoms, cryptophytes, and dinoflagellates. Diatoms were the dominant group most of the year, being dominated by small cell species (single and chain-forming) upstream, and by larger chain-forming species downstream. Cryptophytes had a high contribution to the community in the inner regions of the estuary, while dinoflagellates contributed more for the community composition downstream, where high abundances of harmful algal species were sporadically found. Previous studies on the phytoplankton community dynamics in this estuary are limited to the 1990s. Thus, the present study provides insight into changes in the dominant phytoplankton groups of the Sado Estuary in the last 25 years, namely an increase in cryptophytes over diatoms in the inner estuarine regions, and an increase in dinoflagellates near the estuary mouth.

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Section: Discussionsupporting

confidence: 88%

Section: Methodsmentioning

confidence: 88%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

See 3 more Smart Citations

Spatio-temporal dynamics of phytoplankton community in a well-mixed temperate estuary (Sado Estuary, Portugal)

Santos

Amorim

Brotas

et al. 2022

Sci Rep

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Assessment of changes in severity of compound drought and saltwater intrusion events based on a multi‐index approach in Pearl River estuary

Li,

Liu,

et al. 2023

Hydrological Processes

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Global warming alters the inherent variability of climate variables and induces more frequent extremes of hydroclimatic compound events with substantial impacts. The concurrence of hydrological drought and saltwater intrusion in the estuary can have devastating effects on agricultural production, water security, and ecological health. In this study, the compound drought and saltwater intrusion extreme indices, including the Blend Drought and Saltwater intrusion Index (BDSI), the Compound drought and Saltwater intrusion Index (CDSI) and the Standardized Drought and Saltwater intrusion Index (SDSI), were constructed to monitor compound extremes in the critical zone of Pearl River Estuary during the dry season from 1999 to 2016. The results reveal that the three compound indices can effectively depict different aspects of compound drought and saltwater intrusion extreme events in the critical zone of Pearl River Estuary. Among the three indices, the SDSI performed best in depicting compound drought‐saltwater intrusion events, while the BDSI outperformed the other indices in depicting high value of Standardized Runoff Index (SRI) and Standardized Saltwater intrusion Index (SSI), and the CDSI outperformed the other indices in depicting low values of SRI and SSI. Using those developed compound indices, we found that the frequency of abnormal and moderate compound drought‐saltwater intrusion events increased from 9.26% to 12.03% during the period of 1999–2016, while severe, extreme and exceptional compound drought‐saltwater intrusion events were rare.

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Response of phytoplankton to coastal upwelling: The importance of temporal and spatial scales

Favareto

Brotas

Rudorff

et al. 2023

Limnology & Oceanography

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The Western Iberian Coast (WIC) is characterized by a dynamic coastal upwelling system with interactions between oceanographic features and continental river run‐off. The present study investigates the spatio‐temporal variability in the concentrations of Chlorophyll a (Chl a) and turbidity, and their relationships with physical and other biogeochemical properties along the entire coast of Portugal, as well as the response of phytoplankton to coastal upwelling pulses. In situ data were obtained during four oceanographic campaigns conducted in spring (April–May 2019), autumn (October 2018 and 2019), and early spring (February–March 2020). Upwelling conditions were evaluated through an upwelling index and auxiliary data such as sea surface temperature and height. In the WIC, the in situ surface temperature and salinity have a clear spatial pattern, both increasing from North to South. In autumn 2018 the highest temperatures coincided with the weakening of spring–summer upwelling conditions. Overall, high Chl a was associated with lower temperatures and higher dissolved oxygen concentrations (e.g., spring 2019). During spring 2019, an increase in Chl a, especially in the northern area, was associated with previous upwelling conditions. In early spring 2020, ongoing upwelling conditions in the northern area were associated with high turbidity and nutrients close to the shoreline with no immediate biological responses. An increase in Chl a was visible in satellite imagery a few days later. These results highlight the importance of understanding the complexity of coastal processes in the WIC.

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Tidal variability of water quality parameters in a mesotidal estuary (Sado Estuary, Portugal)

Cited by 29 publications

References 54 publications

Spatio-temporal dynamics of phytoplankton community in a well-mixed temperate estuary (Sado Estuary, Portugal)

Spatio-temporal dynamics of phytoplankton community in a well-mixed temperate estuary (Sado Estuary, Portugal)

Assessment of changes in severity of compound drought and saltwater intrusion events based on a multi‐index approach in Pearl River estuary

Response of phytoplankton to coastal upwelling: The importance of temporal and spatial scales

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