Temporal variability in the suspended sediment load and streamflow of the Doce River

Oliveira, Kyssyanne Samihra Santos; Quaresma, Valéria da Silva

doi:10.1016/j.jsames.2017.06.009

Cited by 82 publications

(40 citation statements)

References 32 publications

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“…The Doce River Shelf (DRS; 17 • 53 S-22 • 18 S) is located in the central zone of the ESCS (Figure 1). The Doce River is the main source of fresh water and sediments for the area, with an average discharge volume of 700 m 3 /s/year and sediment load of 603,106 ton/year [27]. The sedimentation pattern in the adjacent area of the Doce River mouth is directly influenced by the river sediment supply and it is a result of fluvial and meteoceanographic conditions [28].…”

Section: Study Areamentioning

confidence: 99%

Structure of Rhodolith Beds and Surrounding Habitats at the Doce River Shelf (Brazil)

et al. 2020

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The world's largest rhodolith beds have been reported from the Brazilian continental shelf. Highly biodiverse beds are located in Southeast Brazil, but ecological aspects of these beds remain unknown. Despite their ecological importance, rhodolith beds (RBs) have recently been subjected to a severe threat, when more than 35 million cubic meters of mining residues slid down a mountainside on 5 November 2015, after a collapse of a gigantic dam upstream (the Mariana disaster), causing a huge impact on the Doce River. Our aim is to assess rhodolith beds and adjacent coralline formations on the Doce River Shelf (DRS) after the dam collapse. This paper describes the distribution, abundance, vitality, size and shape, as well as unmapped bryozoan rich sediment formations in this area, serving as baseline knowledge for environmental monitoring. Four distinct biogenic sea bottom habitats (bryozoan bottoms, rhodolith beds, carbonate concretions, and reefs) were recognized at different depth ranges with distribution indicated to be mostly related to the local sedimentary regime. Mud sediments dominated the seafloor up to 35 m depth. On the mid shelf, bryozoan bottoms were recorded from 35 to 45 m depth. Crustose coralline algae (CCA) occurring as rhodoliths and carbonate concretions extend over 1953 km 2 in the mid and outer shelf. Rhodolith beds predominate in these areas, totaling 1521 km 2 of sea bottom and were more abundant at depths between 45 and 65 m, occupying an extensive area south of the Doce River mouth. Northward, rhodolith beds are less abundant or absent likely due to the long-term deposition of fine sediments in this region. Carbonate concretions and reefs covered by CCA occupy sparse areas on the outer shelf (65-105 m depth). Differences in rhodolith features recorded, including coverage, density and size, may be related to the Doce River sedimentation and related factors (e.g., hydrodynamics, depth, and light). However, since there are no previous detailed studies on RBs along the DRS, we could not assess the impact of sedimentation of dam wastes on RBs' abundance and density. In any case, these are valuable results for the further monitoring of long-term effects. Considering that the growth of these rhodoliths is relatively slow, and that they are affected by the sedimentation from the Doce River, the implementation of a management and conservation plan for this area is necessary in order to preserve this ecosystem.

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Section: Study Areamentioning

confidence: 99%

Structure of Rhodolith Beds and Surrounding Habitats at the Doce River Shelf (Brazil)

et al. 2020

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“…To the south of the Abrolhos Bank, the shelf width averages 50 km and the shelf break occurs at 60 to 80 m water depth. The Doce river is the main sediment source to the shelf, with an average load of 133 × 10 6 t during the rainy season (November to April) [11]. Shelf morphology varies significantly with four distinct regions: Abrolhos shelf, Doce river shelf, Paleovalley shelf, and the wide-southern inner shelf [10].…”

Section: Study Areamentioning

confidence: 99%

Seabed Morphology and Sedimentary Regimes defining Fishing Grounds along the Eastern Brazilian Shelf

et al. 2018

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Shelf morphology and sedimentary regimes are influenced by processes operating at different temporal and spatial scales and are important records of sea level changes and sediment supply and/or carbonate production. The northern continental shelf of Espírito Santo (Brazil) contains evidence of different sedimentary regimes that distribute diverse and complex marine habitats. Herein, seabed morphology, acoustic images of the seafloor (side scan sonar and sub-bottom profiler), and sediment samples were used to investigate the influence of sedimentary regimes on physical marine habitat distribution. Seabed mapping is also integrated with available data on fisheries to understand the influence of shelf morphology and sedimentology in the usage of distinct fishing gears. The results indicate five morpho-sedimentary facies: terrigenous mud, terrigenous sand, rhodolith beds, carbonate gravel with rhodoliths, and hardground. Through an integrated analysis of the geomorphology and sedimentary distribution, two morpho-sedimentary domains were identified: a sediment-fed shelf adjacent to the Doce River associated with a major mud depocenter and a delta front morphology characterized by gentle slopes and low terrain ruggedness, and a sediment-starved shelf dominated by carbonate sedimentation showing an irregular morphology associated with higher slopes and terrain ruggedness. These contrasting morpho-sedimentary domains are a result of sedimentary responses to sea level fluctuation during Late Quaternary, specially, during the deglaciation processes after the Last Glacial Maximum. The morphological and sedimentary contrasts along the area define the physical habitat distribution. The sediment supply regime area is associated with a terrigenous fine/muddy sedimentation bed, which control the local morphology and favors coastal and delta front progradation. This physical habitat is a well-known shrimp-fishing ground where intense trawling takes place, as well as gillnet fisheries targeting weakfish and croakers. The accommodation regime or low sediment influx area is characterized by carbonate sedimentation associated with hardgrounds and rhodolith beds. In contrast, this physical habitat with scarce sediment supply, facilitates extensive benthic colonization by crustose coralline algae (CCA), which is primarily associated to line fisheries, longlines, and spearfishing. Rhodoliths show a high diversity of CCA and the occurrence of an endemic kelp species. Long-term processes such as relative sea level fluctuations and sediment supply are a legacy for the distribution of benthic

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“…At a deeper analysis level, the author mentions that there is still considerable uncertainty even regarding the nature of the mechanisms involved in soil particle detachment through surface runoff. Oliveira and Quaresma (2017), while analyzing the 56994500 (Colatina) fluviometric station (~88% of the Doce river basin drainage area), concluded that 63% of the variation in suspended sediment load within the Doce River basin can be explained by runoff, and the remaining 37%, by other factors, such as rain intensity, vegetation cover and soil use. Rainfall, considered one of the main forcing in sediment models, also has great uncertainty in its measurements (XUE; CHEN; WU, 2014).…”

Section: /18mentioning

confidence: 99%

Automatic calibration of a large-scale sediment model using suspended sediment concentration, water quality, and remote sensing data

Fagundes

Fan

Paiva

2019

RBRH

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Calibration and validation are two important steps in the application of sediment models requiring observed data. This study aims to investigate the potential use of suspended sediment concentration (SSC), water quality and remote sensing data to calibrate and validate a large-scale sediment model. Observed data from across 108 stations located in the Doce River basin was used for the period between 1997-2010. Ten calibration and validation experiments using the MOCOM-UA optimization algorithm coupled with the MGB-SED model were carried out, which, over the same period of time, resulted in 37 calibration and 111 validation tests. The experiments were performed by modifying metrics, spatial discretization, observed data and parameters of the MOCOM-UA algorithm. Results generally demonstrated that the values of correlation presented slight variations and were superior in the calibration step. Additionally, increasing spatial discretization or establishing a background concentration for the model allowed for improved results. In a station with high quantity of SSC data, calibration improved the ENS coefficient from -0.44 to 0.44. The experiments showed that the spectral surface reflectance, total suspended solids and turbidity data have the potential to enhance the performance of sediment models.

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Temporal variability in the suspended sediment load and streamflow of the Doce River

Cited by 82 publications

References 32 publications

Structure of Rhodolith Beds and Surrounding Habitats at the Doce River Shelf (Brazil)

Structure of Rhodolith Beds and Surrounding Habitats at the Doce River Shelf (Brazil)

Seabed Morphology and Sedimentary Regimes defining Fishing Grounds along the Eastern Brazilian Shelf

Automatic calibration of a large-scale sediment model using suspended sediment concentration, water quality, and remote sensing data

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