Understanding spatial and temporal dynamics of key environmental characteristics in a mesotidal Atlantic estuary (Douro, NW Portugal)

Azevedo, Isabel C.; Duarte, Pedro; Bordalo, Adriano A.

doi:10.1016/j.ecss.2007.07.034

Cited by 60 publications

(37 citation statements)

References 38 publications

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“…Most of these variables are related to eutrophication, and normally are studied in the same context as phytoplankton or macroalgae (see below, and Loureiro et al, 2006;Azevedo et al, 2008;Giordani et al, 2009). However, some legislation, such as the WFD, seeks for independent assessments.…”

Section: Classifying Biological Quality Elementsmentioning

confidence: 99%

Classifying Ecological Quality and Integrity of Estuaries

Borja¹,

Basset²,

Bricker³

et al. 2011

Treatise on Estuarine and Coastal Science

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There is an increasing need in assessing ecological quality and integrity of estuaries and lagoons. This chapter shows the most recent efforts in assessing individual biological elements (from phytoplankton to fishes), together with the integrative tools developed in different geographical areas worldwide. However, reducing complex information from multiple ecosystem elements to a single color or value is a substantial challenge to marine scientists, and requires the integration of different disciplines (chemists, engineers, biologists, ecologists, physics, managers, etc.), to reach agreement on the final assignment of ecological status. Hence, in the near future, emphasis needs to be directed at understanding the complexities of estuarine system functioning rather than simplifying and scaling down the system into smaller components. Provided for non-commercial research and educational use.Not for reproduction, distribution or commercial use.This chapter was originally published in Treatise on Estuarine and Coastal Science, published by Elsevier, and the attached copy is provided by Elsevier for the author's benefit and for the benefit of the author's institution, for noncommercial research and educational use including without limitation use in instruction at your institution, sending it to specific colleagues who you know, and providing a copy to your institution's administrator.All other uses, reproduction and distribution, including without limitation commercial reprints, selling or licensing copies or access, or posting on open internet sites, your personal or institution's website or repository, are prohibited.For exceptions, permission may be sought for such use through Elsevier's permissions site at: Author's personal copy AbstractThere is an increasing need in assessing ecological quality and integrity of estuaries and lagoons. This chapter shows the most recent efforts in assessing individual biological elements (from phytoplankton to fishes), together with the integrative tools developed in different geographical areas worldwide. However, reducing complex information from multiple ecosystem elements to a single color or value is a substantial challenge to marine scientists, and requires the integration of different disciplines (chemists, engineers, biologists, ecologists, physics, managers, etc.), to reach agreement on the final assignment of ecological status. Hence, in the near future, emphasis needs to be directed at understanding the complexities of estuarine system functioning rather than simplifying and scaling down the system into smaller components.

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Section: Classifying Biological Quality Elementsmentioning

confidence: 99%

Classifying Ecological Quality and Integrity of Estuaries

Borja¹,

Basset²,

Bricker³

et al. 2011

Treatise on Estuarine and Coastal Science

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show abstract

“…In the present study, such a relationship was not found, due to water column stratification: levels at the surface remained high throughout the flood due to the presence of a lower-salinity surface layer, resulting from river flow. A similar pattern would be expected for chl a distribution, since previous work in the Douro presented evidence that phytoplankton originates mostly from the river (Bordalo & Vieira 2005, Azevedo et al 2008. The general absence of a vertical gradient in chl a concentration during periods of water column stratification could be explained by the sinking of phytoplankton cells, due to their specific weight generally exceeding that of the water.…”

Section: Environmental Variabilitymentioning

confidence: 69%

“…Also, in this system, the N:P ratio is generally above the Redfield ratio, suggesting an excess of nitrogen availability and a potential limiting role for phosphate (Azevedo et al 2008). Thus, in order to investigate the effect of including these factors in PP estimation, Steele's equation was combined with an exponential limiting function for temperature and a Michaelis-Menten limiting function for phosphate.…”

Section: Methodsmentioning

confidence: 99%

“…In a previous paper (Azevedo et al 2008), we presented a conceptual model of the Douro estuary, showing that the river emerges as the major source of nutrients, chl a, and total particulate matter (TPM), although additional phosphate and TPM anthropogenic sources are present in the middle and lower, highly urbanized, estuarine stretches. Water column salinity structure and freshwater residence time are dependent on river flow magnitude.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Temporal and spatial variability of phytoplankton photosynthetic characteristics in a southern European estuary (Douro, Portugal)

Azevedo¹,

Duarte²,

Bordalo³

2010

Mar. Ecol. Prog. Ser.

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“…In general, salinity was lower at most upstream stations (E1, E1a) and higher at most downstream stations (E2, E3 and E3a). Seasonal variations and along to the estuarine gradient as those indicated are very common in Portuguese estuaries (Moreira et al 1993;Azevedo et al 2008;Chainho et al 2008;Sousa et al 2008b;Costa-Dias et al 2010b;Medeiros et al 2012). Winter and spring were the wettest seasons compared to summer, which was generally drier.…”

Section: Discussionmentioning

confidence: 99%

Factors affecting the distribution of epibenthic biodiversity in the Cávado estuary (NW Portugal)

Carvalho

Santos

2013

RGCI

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The epibenthic fauna of the lower Cávado estuary at five sampling stations was studied over a period of two years. We examined the spatial and seasonal distribution of different species and analysed temperature, salinity, dissolved oxygen, precipitation and sediment type, which are all important features of estuarine dynamics. A total of 15 taxa were identified. Crustaceans had the highest levels of abundance (91%) and biomass (87%). Crangon crangon was the most abundant species (75%) and Carcinus maenas had the highest biomass (71%). No exotic species were recorded. Multivariate analysis showed two different spatial assemblages, one corresponding to stations nearest to the mouth (higher abundance values) and other to the upstream stations. The Shannon diversity index was highest at the margin station further upstream. Three different assemblages could be distinguished, separating summer/autumn (higher values of abundance) from spring and from winter.According to BIOENV analysis, dissolved oxygen, water temperature and salinity were the environmental variables responsible for the spatial and seasonal distribution of epibenthos, explaining 17.2% of variability. Abundance and biomass were better correlated with water temperature. Sediment type was also important in epibenthic spatial distribution, being abundance, biomass and diversity indexes better correlated with fine sediment (<0.125mm). Keywords: epibenthos; estuarine ecosystem; diversity; environmental variables Resumo A fauna epibentónica do estuário inferior do Rio Cávado foi estudada em cinco estações de amostragem durante um período de dois anos. Apresentamos a distribuição espacial e sazonal das diferentes espécies e uma análise da temperatura, salinidade, oxigénio dissolvido, precipitação e tipo de sedimento, sendo todas, importantes características da dinâmica estuarina. Foram identificados um total de 15 taxa. Os crustáceos apresentaram os valores mais elevados de abundância (91%) e biomassa (87%). Crangon crangon foi a espécie mais abundante (75%) e Carcinus maenas apresentou o valor de biomassa mais elevado (71%

show abstract

Understanding spatial and temporal dynamics of key environmental characteristics in a mesotidal Atlantic estuary (Douro, NW Portugal)

Cited by 60 publications

References 38 publications

Classifying Ecological Quality and Integrity of Estuaries

Classifying Ecological Quality and Integrity of Estuaries

Temporal and spatial variability of phytoplankton photosynthetic characteristics in a southern European estuary (Douro, Portugal)

Factors affecting the distribution of epibenthic biodiversity in the Cávado estuary (NW Portugal)

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