scholarly journals Algal blooms and trophic state in a tropical estuary blocked by a dam (northeastern Brazil)

2021 ◽  
Vol 69 ◽  
Author(s):  
Ana Karoline Duarte dos Santos Sá ◽  
Marco Valerio Jansen Cutrim ◽  
Denise Santos Costa ◽  
Lisana Furtado Cavalcanti ◽  
Francinara Santos Ferreira ◽  
...  
Keyword(s):  
Algal Blooms ◽  
Trophic State ◽  
Northeastern Brazil ◽  
Tropical Estuary

scholarly journals Diel and seasonal changes in the macrozooplankton community of a tropical estuary in Northeastern Brazil

2003 ◽  
Vol 20 (3) ◽  
pp. 439-446 ◽  
Author(s):  
Tâmara de Almeida e Silva ◽  
Sigrid Neumann-Leitão ◽  
Ralf Schwamborn ◽  
Lúcia Maria de Oliveira Gusmão ◽  
Dilma Aguiar do Nascimento-Vieira
Keyword(s):  
Seasonal Changes ◽  
Northeastern Brazil ◽  
Tropical Estuary

scholarly journals Space time evolution of the trophic state of a subtropical lagoon: Lagoa da Conceição, Florianópolis Island of Santa Catarina, Brazil

RBRH ◽  
2017 ◽  
Vol 22 (0) ◽  
Author(s):  
Victor Eduardo Cury Silva ◽  
Davide Franco ◽  
Alessandra Larissa Fonseca ◽  
Maria Luiza Fontes ◽  
Alejandro Rodolfo Donnangelo
Keyword(s):  
Water Column ◽  
Trophic Level ◽  
Algal Blooms ◽  
Trophic State ◽  
Coastal Lagoons ◽  
Principal Component ◽  
Quality Data ◽  
Santa Catarina ◽  
Water Quality Data ◽  
Subtropical Lagoon

ABSTRACT High levels of eutrophication in coastal lagoons due to human activity have been documented worldwide. Among the main impacts observed are anoxia, hypoxia, toxic algal blooms, fish kills, loss of biodiversity and loss of bathing. This study aimed to evaluate the evolution of the trophic state of Lagoa da Conceição, a subtropical lagoon located in an urbanized watershed on the island of Santa Catarina - Brazil. Spatio temporal patterns of stratification and eutrophication were investigated to understand the main biochemical changes over time. The water quality data were obtained from field campaigns supplemented with literature of the last 15 years. The vertical structure of the water column and the trophic state were evaluated by the stratification index and the TRIX index, respectively. Analyses of variance were performed in order to identify possible temporal variations in vertical stratification and trophic level. Eutrophication effects on biogeochemical cycles were verified through a multi-dimensional cluster analysis (MDS) and correlations between variables related to physical, chemical and biological processes were verified by principal component analysis (PCA). The results showed that the water column is homogeneous in all regions except in the central region of the lagoon, and the highest ammonia concentrations and lowest dissolved oxygen concentrations with periods of anoxia are observed in bottom waters. The study looked at the high trophic level of the lagoon and its inability to process the biogeochemical changes imposed by urban development.

Insights into the dynamics of harmful algal blooms in a tropical estuary through an integrated hydrodynamic-Pyrodinium-shellfish model

Harmful Algae ◽  
2018 ◽  
Vol 80 ◽  
pp. 1-14 ◽  
Author(s):  
Aletta T. Yñiguez ◽  
Jennifer Maister ◽  
Cesar L. Villanoy ◽  
Josephine Dianne Deauna ◽  
Eileen Peñaflor ◽  
...  
Keyword(s):  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Tropical Estuary

scholarly journals Assessment of Physical-Chemical Characteristics of Water and Sediments from a Brazilian Tropical Estuary: Status and Environmental Implications

2012 ◽  
Vol 2012 ◽  
pp. 1-14 ◽  
Author(s):  
Madson de G. Pereira ◽  
Marta V. A. S. de Andrade ◽  
Vanessa C. Ornelas ◽  
Raimunda A. N. de Almeida ◽  
Maurício P. F. Fontes ◽  
...  
Keyword(s):  
Northeastern Brazil ◽  
Chemical Characteristics ◽  
Tropical Estuary ◽  
Total Organic Matter ◽  
Environmental Standards ◽  
Environmental Implications ◽  
Environmental Preservation ◽  
X Ray ◽  
Physical Chemical

The environmental quality of the Jacuípe River's estuary (very important in northeastern Brazil) was assessed during 2007 and 2008. In water, concentrations (mg L−1) ofNO2-(<0.004 to 0.016),NO3-(0.01 to 0.33), solublePO43-(<0.02 to 0.22), dissolved oxygen (3.9 to 9.6), total contents (mg L−1) of Cd (<0.001), Cu (<0.01), Pb (<0.01), and Zn (<0.1), pH (5.60 to 8.00), and electrical conductivity (0.12 to 48.60 mS cm−1) agreed with environmental standards. In sediments, clay and total organic matter (%, m/m) varied, respectively, from 8.8 to 12.0 and from 1.1 to 8.8, while infrared, thermogravimetric profile, electronic micrograph, as well as X-Ray analyses showed desirable adsorptive characteristics. However, maximum exchangeable levels (mg kg−1) of Cd (1.3), Cu (44.6), Pb (35.7), and Zn (43.7) and their respective maximum pseudototal concentrations (mg kg−1): 19.4, 95.1, 68.2, and 30.3 were below the recommended limits. In this sense, it was possible to demonstrate good environmental preservation even with the growing number of industries and touristic activities in the evaluated estuarine area.

Reproductive biology of the protandric hermaphrodite fat snook Centropomus parallelus Poey 1860 in a tropical estuary, northeastern Brazil

2019 ◽  
Vol 54 (3) ◽  
pp. 225-235
Author(s):  
Daniel Alvares Silveira de Assis ◽  
Danieli Marinho Nobre ◽  
Marcelo Carneiro de Freitas ◽  
Leonardo Evangelista Moraes ◽  
Alexandre Clistenes de Alcântara Santos
Keyword(s):  
Reproductive Biology ◽  
Northeastern Brazil ◽  
Tropical Estuary ◽  
Fat Snook

scholarly journals Feeding ecology of three juvenile mojarras (Gerreidae) in a tropical estuary of northeastern Brazil

2016 ◽  
Vol 14 (1) ◽  
Author(s):  
Antônio Limeira Felinto de Araújo ◽  
Renato Pereira Dantas ◽  
André Luiz Machado Pessanha
Keyword(s):  
Feeding Ecology ◽  
Resource Partitioning ◽  
Salinity Gradient ◽  
Northeastern Brazil ◽  
Tropical Estuary ◽  
Beach Seine ◽  
Opposite Pattern ◽  
Main Prey ◽  
Nursery Habitats ◽  
Prey Items

ABSTRACT Distributions and feeding ecology of mojarra species from shallow water of a tropical estuary in Northeastern Brazil were observed aiming to investigate differences in distribution and resource partitioning among juveniles of three species of mojarras. Fishes were collected with a beach seine across four sites along a salinity gradient from January to December of 2011. Highest abundances were recorded during the rainy season in the upper and middle estuary. Microcrustaceans, mainly copepods, were the preferential prey items of all mojarras, irrespective of size or hydrological season, suggesting these areas may be important nursery habitats. Juveniles of mojarra used two important mechanisms for exploitation of resources: (1) spatial segregation along the salinity and temperature gradient, such as abundance of Eucinostomus melanopterus increased from downstream to upstream estuary, while Eugerres brasilianus displayed an opposite pattern; (2) differences related to the volumetric proportion of the main prey items, with indications that E. melanopterus and Diapterus rhombeus fed predominantly on Calanoida and Cyclopoida, while the diet of E. brasilianus was dominated by items of infauna. Such strategies were important for resource partitioning, favouring the coexistence of these three species in the estuary.

scholarly journals Assessing Water and Nutrient Long-Term Dynamics and Loads in the Enxoé Temporary River Basin (Southeast Portugal)

Water ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 354 ◽  
Author(s):  
David Brito ◽  
Ramiro Neves ◽  
Maria Branco ◽  
Ângela Prazeres ◽  
Sara Rodrigues ◽  
...  
Keyword(s):  
Algal Blooms ◽  
Field Data ◽  
Trophic State ◽  
Assessment Tool ◽  
Geometric Mean ◽  
Light Availability ◽  
Nutrient Loads ◽  
Management Scenarios ◽  
High Concentrations

The Enxoé reservoir has been exhibiting frequent high chlorophyll-a concentrations (reaching a geometric mean six times the national limit for eutrophication of 10 μg L−1) since 2000, and represents the reservoir with the highest eutrophic state in Portugal. Toxic algal blooms have also been observed, which pose serious challenges to water managers, as the reservoir is used for potable water production. In an effort to contribute to the reduction of the reservoir trophic state, the watershed inputs (monthly flows, sediment, nitrogen (N) and phosphorus (P) loads) were characterized with the Soil Water Assessment Tool (SWAT). Field data were collected in the ungauged watershed during 2010 and 2011. Model results were then used to characterize the long-term watershed dynamics in terms of water and nutrients. SWAT estimates of the simulated flow, and the sediment and nutrient loads were in good agreement with field data (R2 between 0.42–0.78; Nash-Sutcliffe efficiencies between 0.19–0.75). The Enxoé River was characterized by a temporary flushy regime where high concentrations were transported in short time periods. As a result, nutrient loads delivered to the Enxoé reservoir were estimated to be 18 tonN year−1 and 0.7 tonP year−1 (30 years’ simulation), reaching the reservoir mainly by runoff. These results were consistent with the gentle slopes, extensive agricultural activities, and low urban pressure observed in Enxoé. The magnitude of the nutrient exports suggests that the reservoir eutrophication may also be linked to the reservoir geometry (average depth of 5 m), which provides high light availability to the bottom sediments. Thus, SWAT results were integrated into a reservoir model to depict the origin of the Enxoé trophic state and test management scenarios that may reduce it.

scholarly journals Microphytoplankton biomass and trophic state of the Estuarine Region of São Francisco River (northeastern Brazil)

2017 ◽  
Vol 20 (2) ◽  
Author(s):  
Enaide Marinho Melo-Magalhães ◽  
Ariadne Do Nascimento Moura ◽  
Paulo Ricardo Petter Medeiros ◽  
Maria Luise Koening
Keyword(s):  
Trophic State ◽  
Northeastern Brazil ◽  
Sao Francisco River ◽  
São Francisco River ◽  
Estuarine Region
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