Tidal and Physicochemical Effects on Phytoplankton Community Variability at Tagus Estuary (Portugal)

Cereja, Rui; Brotas, Vanda; Cruz, Joana; Rodrigues, Marta; Brito, Ana C.

doi:10.3389/fmars.2021.675699

Cited by 16 publications

(25 citation statements)

References 106 publications

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“…This region is also the most susceptible to seasonal variations of the weather and along the estuary, these parameters showed higher values during spring and summer 11 . As for the nutrients, they are usually detected in higher concentrations in the inner channels of the estuary 12 , similarly to what was observed in the Tagus Estuary 13 . Overall, the water quality parameters in estuaries like Sado, present a strong seasonality (mainly due the variation of air temperature and rainfall) and vary in response to physical transport processes 14 , varying with the river flow and the tidal cycle.…”

supporting

confidence: 70%

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

Nascimento

Biguino

Borges

et al. 2021

Sci Rep

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To establish effective water quality monitoring strategies in estuaries, it is imperative to identify and understand the main drivers for the variation of water quality parameters. The tidal effect is an important factor of the daily and fortnightly variability in several estuaries. However, the extent of that influence on the different physicochemical and biological parameters is still overlooked in some estuarine systems, such as the Sado Estuary, a mesotidal estuary located on the west coast of Portugal. The main objective of this study was to determine how the water quality parameters of the Sado Estuary varied with the fortnightly and the semidiurnal tidal variation. To achieve this goal, sampling campaigns were conducted in May/18, Nov/18 and Jun/19, under neap and spring tidal conditions, with data collection over the tidal cycle. Results were observed to be significantly influenced by the tidal variation, in a large area of the estuary. Flood seemed to mitigate possible effects of nutrient enrichment in the water column. Additionally, significant differences were also observed when considering the different sampling stations. Temperature, Suspended Particulate Matter (SPM) and nutrients showed the highest values at low water. Lastly, the implications of the tidal variability in the evaluation of the water quality according to Water Framework Directive were also discussed, highlighting the importance of studying short-time scale variations and the worst-case scenario to ensure water quality is maintained. These findings are relevant for the implementation of regional management plans and to promote sustainable development.

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confidence: 70%

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

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Biguino

Borges

et al. 2021

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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: 89%

“…Diatoms were the dominant group, favored by the well-mixed nature of the estuary 15 . Diatoms dominance is a common pattern in this estuary and in other estuarine systems 18 , 22 , 44 , 51 , 52 . This study showed that several diatom species dominated the stations located in the inner region, with a high contribution of benthic/epibenthic species (e.g., Gyrosigma/Pleurosigma group, Nitzschia sigma and Melosira nummuloides ), while several chain-forming diatom species dominated near the estuary mouth (e.g., Chaetoceros spp., Leptocylindrus danicus and Guinardia delicatula ).…”

Section: Discussionmentioning

confidence: 70%

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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“…The reach of freshwater intrusion is clearly on the surface layer with a difference of up to 7 km. These high fluctuations can cause significant differences between samples obtained at different tidal conditions (Cereja et al, 2021).…”

Section: Vertical Characteristic Of Water Massmentioning

confidence: 99%

Distribution of Salinity and Temperature in Musi Estuary: Using Vertical Salinity Gradient for Estuary Classification Zone

Heltria

Yuliardi²,

Kismawardhani³

et al. 2022

J. Ilmu dan Teknologi Kelautan Tropis

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Musi estuary is the mouth of the Telang and Musi rivers directly adjacent to the Bangka Strait. During flood (ebb) we see the distribution of salinity increases (decreases) which is known through the vertical distribution using CTD. The TS diagram is used to see the water mass characteristics the study area. Data-Interpolating Variational Analysis (DIVA) method is used to interpolate and visualize data from vertical and spatial temperature, salinity and density data. The classification of the Musi estuary zone is identified based on the value of the distribution of salinity, which considers the exchange of circulating salinity at flood and ebb. The density of the water mass is significantly affected by the proven graded salinity. While the temperature distribution does not change significantly with depth, the spatial distribution indicates that the temperature in the estuary is lower than in the upstream and ocean areas. The spatial distribution of salinity indicates that high salinity enters the estuary towards the river further at flood than at ebb. Salinity distribution ranges from 0.5 to 30 psu and temperatures between 29 and 33 oC from horizontal and vertical sections. The pattern of salinity distribution in the Musi river estuary was identified, consisting of three zones representing salinity conditions in the study area, namely the Polyhaline, Mesohaline, and Olygohaline zones.

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Tidal and Physicochemical Effects on Phytoplankton Community Variability at Tagus Estuary (Portugal)

Cited by 16 publications

References 106 publications

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

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

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

Distribution of Salinity and Temperature in Musi Estuary: Using Vertical Salinity Gradient for Estuary Classification Zone

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