Reviewing sedimentological and hydrodynamic data of large shallow coastal lagoons for defining mud depocenters as environmental monitoring sites

Bortolin, Eduardo Calixto; Weschenfelder, Jair; Fernandes, Elisa Helena Leão; Bitencourt, Liliane Paranhos; Möller, Osmar Olinto; García-Rodríguez, Felipe; Toldo, Elírio E.

doi:10.1016/j.sedgeo.2020.105782

Cited by 16 publications

(13 citation statements)

References 46 publications

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“…After the river load reaches the lagoon, solids in suspension can be deposited and the exceeding material is exported towards the ocean. Bortolin et al (2020) showed that this fine suspended load is deposited inside Patos Lagoon forming mud depocenters established according the hydrodynamic conditions. The Inlet panel (Figure 7D) shows that from June to November the export of SPM to the Atlantic Ocean is higher.…”

Section: Seasonal To Interdecadal Response Of Suspended Particulate M...mentioning

confidence: 94%

“…Therefore, it is common for El Niño years to have occasionally low SPM concentrations during the dryer season (austral summer and autumn), as it is common to have high SPM concentrations during the wet seasons (austral winter and spring) even in the course of La Niña events, although the HIP configuration is more frequent and more intense during El Niño years. According to previous studies, the material reaching the lagoon is distributed by internal currents developed by wind effects (Bortolin et al, 2020), which control the sedimentation processes (Távora et al, 2019) and enhances or reduces the discharge to the Ocean (Moller et al, 2001).…”

Section: Conceptual Model About the Dynamics Of Suspended Particulate...mentioning

confidence: 99%

“…The plume evolves its farfield towards the southern cells of Patos Lagoon (Figure 8), enhanced by the predominant NE winds (frequent during summer) (Hetland and Hsu, 2013;Távora et al, 2019). Although the Guaíba River contributes with almost 61% of the suspended load delivered to Patos Lagoon (Vaz et al, 2006), the suspended material has to be transported for more than 200 km to be exported to the ocean (Fernandes et al, 2002), and part of the fine material remains in the lagoon, mainly in the northern cell (Bortolin et al, 2020). Previous studies already reported decreasing sedimentation rates from the northern cell to the southern cell of the lagoon (Ivanoff et al, 2020).…”

Section: Conceptual Model About the Dynamics Of Suspended Particulate...mentioning

confidence: 99%

“…The Patos Lagoon reaches longer residence times (∼ 108 days) (Toldo et al, 2000;Fernandes et al, 2002), especially during low discharge circumstances, and this low discharge can cause a delay in the spread of the SPM plume towards the south. For this reason, material discharged during austral spring can be dissipated southward by NE winddriven currents (Bortolin et al, 2020); a low discharge pattern that lasts until summer (Távora et al, 2019). Therefore, the fine sediments discharged tend to remain and accumulate in the mud depocenters of Patos Lagoon, especially in the northern cell (Bortolin et al, 2020).…”

Section: Conceptual Model About the Dynamics Of Suspended Particulate...mentioning

confidence: 99%

“…This important depositional basin receives SPM from three main tributaries Guaíba and Camaquã rivers, and the São Gonçalo Channel (SGC), which connects Patos and Mirim Lagoons, which together cover 14,000 km 2 (Bortolin et al, 2020). Once inside the lagoon, the coarser fractions of suspended sediment tend to deposit in the upper course of the system and the SPM fine fraction is either transported in suspension or deposited in preferential zones, responding to autogenic forcings (Bortolin et al, 2020), such as the variability in freshwater discharges and wind action (Távora et al, 2019;Bitencourt et al, 2020). The fine SPM fraction which reaches Patos Lagoon estuary moves towards the coast through Rio Grande Channel, which has predominant ebb flow (Moller et al, 2001;Fernandes et al, 2002), but is also subject to flocculation processes during flood flows (Ávila et al, 2021).…”

Section: Introductionmentioning

confidence: 99%

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Long-Term Variability on Suspended Particulate Matter Loads From the Tributaries of the World’s Largest Choked Lagoon

2022

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Continental freshwater contributions are the main long-term control on the variability of suspended particulate matter (SPM) concentrations in choked lagoons. The current work aims to assess the seasonal to interdecadal variability in SPM concentrations from Patos Lagoon tributaries, as a case study towards the understanding of tributaries contributions to coastal lagoons. Thus, an interdecadal dataset (1984–2020) was collected in the region of the tributaries of Patos Lagoon (southern Brazil), integrating Landsat series (653 scenes) and in situ measurements. SPM concentrations were estimated from the scenes using a semi-analytical multiwavelength algorithm, applied in the regions of the lower course of the tributaries. Results identified SPM concentrations variability in seasonal scales, enhanced by El Niño Southern Oscillation (ENSO) in interannual time scales, also influencing in interdecadal trends. The seasonal SPM concentration variability reached 50 g.m–3 to each tributary. Higher SPM concentration values occurred from winter to spring, enhanced during El Niño periods and frequently reaching annual means higher than 100 g.m–3. Periods from summer to autumn, however, presented lower SPM concentrations, especially during La Niña periods, when the mean annual SPM concentration remained mostly below 50 g.m–3. Seasonal and interannual (ENSO) forcings combined developed configurations of high input periods (HIP) and low input periods (LIP). During the LIP, the river plumes are limited to their tributary zone of influence and the whole lagoon has reduced SPM concentrations. During the HIP, the river plumes spread over the lagoon sub-environments, and the SPM concentrations of all tributaries reach the estuarine zone and the ocean. Thus, the mentioned natural phenomena influence the river plumes spreading, the SPM concentrations in the lagoon, and the export to the Atlantic Ocean in time scales varying from seasonal to interdecadal.

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Section: Seasonal To Interdecadal Response Of Suspended Particulate M...mentioning

confidence: 94%

Section: Conceptual Model About the Dynamics Of Suspended Particulate...mentioning

confidence: 99%

Section: Conceptual Model About the Dynamics Of Suspended Particulate...mentioning

confidence: 99%

Section: Conceptual Model About the Dynamics Of Suspended Particulate...mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Long-Term Variability on Suspended Particulate Matter Loads From the Tributaries of the World’s Largest Choked Lagoon

2022

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Patos Lagoon, Brazil, Suspended Particulate Matter (SPM) data compendium

Távora

Fernandes

Möller

2021

Geoscience Data Journal

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Patos Lagoon is the largest choked coastal lagoon in the world (250 km long, 40 km wide and mean depth of 5 m), with banks formed by sand and predominantly muddy bottom. The circulation is mainly driven by wind and river flow, with a minor contribution of the local microtidal regime. This lagoon is one of the most studied coastal water bodies in Brazil. The Patos Lagoon suspended particulate matter (SPM) data compendium consists of over four decades of SPM data gathered from multiple research and monitoring projects. Data consist of SPM in situ samplings, remote sensing derived SPM estimates, rating curve approach for SPM estimates and SPM derived from turbidity measurements. Only measurements with a detailed description of the sampling and analysis protocols were used. The present data set offers valuable contributions as it allows the assessment of trends on the data and the short-and long-term spatial and temporal variability of SPM concentrations in an area where permanent monitoring stations are not available. From these records, the SPM concentrations ranged from 0.4 g/m 3 up to 1,000 g/m 3 . The Patos Lagoon SPM Compendium has been made publicly available at Tavora, Fernandes and Möller (2020).

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