Suspended-Sediment Distribution Patterns in Tide-Dominated Estuaries on the Eastern Amazon Coast: Geomorphic Controls of Turbidity-Maxima Formation
| Autor: | Andrea S. Ogston, Ariane M.M. Silva, Charles A. Nittrouer, Nils E. Asp, Eduardo Siegle, José Diego Gomes, Vando J.C. Gomes |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: |
0106 biological sciences
010504 meteorology & atmospheric sciences Amazonian Geography Planning and Development Aquatic Science 01 natural sciences Biochemistry tides River mouth suspended-sediment concentration Turbidity TD201-500 0105 earth and related environmental sciences Water Science and Technology geography geography.geographical_feature_category Water supply for domestic and industrial purposes Amazon rainforest 010604 marine biology & hydrobiology Sediment Estuary Hydraulic engineering tidal prism estuaries turbidity Oceanography Environmental science Tidal prism Mangrove TC1-978 OCEANOGRAFIA |
| Zdroj: | Water, Vol 13, Iss 1568, p 1568 (2021) Repositório Institucional da USP (Biblioteca Digital da Produção Intelectual) Universidade de São Paulo (USP) instacron:USP Water Volume 13 Issue 11 |
| ISSN: | 2073-4441 |
| Popis: | In tide-dominated estuaries, maximum-turbidity zones (MTZs) are common and prominent features, characterized by a peak in suspended-sediment concentration (SSC) associated with estuarine processes. The Brazilian Amazon coast includes many estuaries, experiencing macrotidal conditions. MTZs are expected to occur and are crucial for sediment delivery to the longest continuous mangrove belt of the world. The area is under influence of the Amazon River plume (ARP), the main SSC source, as local rivers do not deliver substantial sediment supply. To assess the processes that allow the ARP to supply sediment to the estuaries and mangrove belt along the Amazon coast, the results from previous individual studies within five Amazon estuaries (Mocajuba, Taperaçu, Caeté, Urumajó and Gurupi) were compared with regards to SSC, salinity, morphology and tidal propagation. This comparison reinforces that these estuaries are subject to similar regional climate and tidal variations, but that their dynamics differ in terms of distance from the Amazon River mouth, importance of the local river sediment source, and morphology of the estuarine setting. The Urumajó, Caeté and Gurupi are hypersynchronous estuaries where perennial, classic MTZs are observed with SSC > 1 g·L−1. This type of estuary results in transport convergence and MTZ formation, which are suggested to be the main processes promoting mud accumulation in the Amazonian estuaries and therefore the main means of mud entrapment in the mangrove belt. The Mocajuba and the Taperaçu estuaries showed synchronous and hyposynchronous processes, respectively, and do not present classic MTZs. In these cases, the proximity to the ARP for the Mocajuba and highly connected tidal channels for the Taperaçu estuary, assure substantial mud supply into these estuaries. This study shows the strong dependence of the estuaries and mangrove belt on sediment supply from the ARP, helping to understand the fate of Amazon River sediments and providing insights into the mechanisms providing sediment to estuaries and mangroves around the world, especially under the influence of big rivers. |
| Databáze: | OpenAIRE |
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