Sediment dynamics of a tropical tide-dominated estuary: Turbidity maximum, mangroves and the role of the Amazon River sediment load

Nils, E.; Gomes, Vando José Costa; Schettini, Carlos Augusto França; Souza‐Filho, Pedro Walfir M.; Siegle, Eduardo; Ogston, A. S.; Nittrouer, Charles A.; Silva, J.N.S.; Nascimento, Wilson R.; Souza, S. R.; Pereira, Luci Cajueiro Carneiro; Queiroz, M.C.

doi:10.1016/j.ecss.2018.09.004

Cited by 59 publications

(52 citation statements)

References 32 publications

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“…As the evolution and spatial patterns of the ETM are mainly modified by river discharge and by tide-induced transport, these would be the principal drivers of mud intrusion into the estuary, as also suggested by Orseau et al [14]. Landward mud ingression has also been identified as the main source of sediments in other estuaries under the influence of the Amazon River plume [59], confirming the influence of muddy deposits from the Amazon in the sediment dynamics and potential long-term infill of estuaries in northern South America. It may be expected that, during inter-bank phases separating mud-bank phases, these Amazon-influenced estuaries would have a functional regime similar to that of other tropical estuaries elsewhere, with minimal influence of outside mud-sourcing.…”

Section: Medium-term (2013-2019) Variation: the Influence Of Periodicmentioning

confidence: 65%

“…As a consequence of this stratification, high resuspension of SPM is impeded [54] and low SPM values are observed at the surface of the water column (Figure 6c). Therefore, flood tides are characterized by low SPM values in comparison to ebb tides, as observed by Asp et al [59] in a river on the coast of Para State in North Brazil, also under the influence of the Amazon. No clear influence of wind velocity values is detected when the different scenes are compared ( Figure 6).…”

Section: Spm and Variability Of Etm Extension Due To External Conditionsmentioning

confidence: 70%

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Dynamics of the Estuarine Turbidity Maximum Zone from Landsat-8 Data: The Case of the Maroni River Estuary, French Guiana

et al. 2020

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The estuarine turbidity maximum (ETM) zone occurs in river estuaries due to the effects of tidal dynamics, density-driven residual circulation and deposition/erosion of fine sediments. Even though tropical river estuaries contribute proportionally more to the sediment supply of coastal areas, the ETM in them has been hardly studied. In this study, surface suspended particulate matter (SPM) determined from OLI (Operational Land Imager)-Landsat 8images was used to gain a better understanding of the spatio-temporal dynamics of the ETM of the tropical Maroni estuary (located on the Guianas coast, South America). A method to estimate the remotely-sensed ETM location and its spatiotemporal evolution between 2013 and 2019 was developed. Each ETM was defined from an envelope of normalized SPM values > 0.6 calculated from images of the estuary. The results show the influence of the well-marked seasonal river discharge and of tides, especially during the dry season. The ETM is located in the middle estuary during low river-flow conditions, whereas it shifts towards the mouth during high river flow. Neap–spring tidal cycles result in a push of the ETM closer to the mouth under spring-tide conditions or even outside the mouth during the rainy season. An increase in SPM, especially since 2017, coincident with an extension of the ETM, is shown to reflect the periodic influence of mud banks originating from the mouth of the Amazon and migrating along the coast towards the Orinoco (Venezuela). These results demonstrate the advantages of ocean color data in an exploratory study of the spatio-temporal dynamics of the ETM of a tropical estuary, such as that of the Maroni.

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Section: Medium-term (2013-2019) Variation: the Influence Of Periodicmentioning

confidence: 65%

Section: Spm and Variability Of Etm Extension Due To External Conditionsmentioning

confidence: 70%

Dynamics of the Estuarine Turbidity Maximum Zone from Landsat-8 Data: The Case of the Maroni River Estuary, French Guiana

et al. 2020

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“…The number in ( ) represents the %. amplitude grew (17%), while the others the amplitude grew was of ~10%, characterizing hypersyncronous behavior (Nichols and Biggs, 1987), what has been observed in other Brazilian estuaries (Truccolo and Schettini, 1999;Asp et al, 2018). The tidal behavior along an estuary can be dynamically balanced between channel convergence, which produces tidal grow, and friction, which reduces the range (Friedrichs, 2010), so in the PSW the former prevail.…”

mentioning

confidence: 75%

Tides and sea level variability decomposition in the Port of Santos Waterway

Schettini

Truccolo

Mattos³

et al. 2019

Braz. j. oceanogr.

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“…However, it is clear that only a small fraction of Amazon River sediment feeds the AMMC. Also, local river contributions are much smaller than the potential capture amount (Asp et al, ). Together with the Nascimento et al () results, it can be inferred that most of the sediment originates from internal reworking across the mangrove fringe, and there is likely a seasonal change that favors deposition in the mangrove flats during the dry season and erosion in the wet season.…”

Section: Discussionmentioning

confidence: 99%

Circulation and fine‐sediment dynamics in the Amazon Macrotidal Mangrove Coast

Schettini

Nils

Ogston

et al. 2019

Earth Surf Processes Landf

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The Amazon Macrotidal Mangrove Coast (AMMC) is a large (~7500 km2) contiguous mangrove fringe eastwards from the Amazon River mouth. It encompasses dozens of interconnected bays intercalated with mangrove peninsulas. Mud accumulates on the mangrove flats, whereas the bed of the bays and channels is generally sandy. In this study we investigated the circulation, sediment transport and deposition in a central site at one of these mangrove peninsulas. The study was undertaken during the dry period, when there is no influence of the Amazon River plume and minimum local freshwater inflow. Current and suspended‐sediment concentration were monitored in a feeder channel on the mangrove flat along a ~1000 m section oriented along the peninsula axis. Sediment deposition was also measured on the flat. Our results show there was a strong exchange between the neighboring bays. Channel currents were flood dominant, reaching up to >1 m s−1, with residual water and sediment transport westwards. Suspended sediment concentration (SSC) in the channel was directly related to velocity magnitude, ranging between 50 and 350 mg L−1. The flat was flooded in a way that indicated the tidal wave evolves westwards, nearly parallel to the AMMC shoreline. Currents on the flats were much slower than those in the channel and showed slight ebb dominance. However, SSC was higher during the flood than ebb, clearly indicating settling during the current deceleration and limited erosion during the following ebb–flow acceleration. The net sediment transport across the section was 60 tons westwards for the period of the experiment (~4 days). The mean deposition rate was 0.006 kg m−2 s−1 (or 1.4 kg m−2 per tide), which was higher than rates from other reported assessments in mangroves. The set of results indicate very large internal sediment reworking in the AMMC. © 2019 John Wiley & Sons, Ltd.

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Sediment dynamics of a tropical tide-dominated estuary: Turbidity maximum, mangroves and the role of the Amazon River sediment load

Cited by 59 publications

References 32 publications

Dynamics of the Estuarine Turbidity Maximum Zone from Landsat-8 Data: The Case of the Maroni River Estuary, French Guiana

Dynamics of the Estuarine Turbidity Maximum Zone from Landsat-8 Data: The Case of the Maroni River Estuary, French Guiana

Tides and sea level variability decomposition in the Port of Santos Waterway

Circulation and fine‐sediment dynamics in the Amazon Macrotidal Mangrove Coast

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