Estuary neoicnology: a sedimentary approach towards morphodynamics

• Grant number: 22/01317-7
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: January 01, 2023
• End date: December 31, 2023
• Field of knowledge: Interdisciplinary Subjects
• Principal Investigator: Milene Fornari
• Grantee: Ana Lorenzetti Fortes
• Host Institution: Instituto de Biociências (IB-CLP). Universidade Estadual Paulista (UNESP). Campus Experimental do Litoral Paulista. São Vicente , SP, Brazil
• Associated scholarship(s): 23/02524-9 - Expanding a neoichnological study on the Brazilian coast: application of novel field and analytic methods, BE.EP.IC

Abstract

Among the sedimentary records, the biogenic structures that occur in situ are fundamental to refining the paleoenvironmental meaning of the deposits, as well as they are precise and reliable sociological data to infer climate-eustatic changes. Studying biogenic structures in estuaries is of special interest, since they are environments under the direct influence of the interaction between waves, tides, and river discharge that alter the physicochemical characteristics of the substrate, and, therefore, can affect the occurrence, distribution, and types of structures. However, even though estuaries are common environments along the coast of São Paulo, and they represent one of the most complex systems in the coastal zone, detailed studies that integrate neoichnology and sedimentology have not yet been carried out. Within this theme, in this project, three estuaries of the coast of São Paulo were selected for study: Itaguaré, Canal de Bertioga, and Ribeira de Iguape. The major goal is to understand the spatial distribution of modern biogenic sedimentary structures in estuarine morphological features concerning the textural characteristics of sediments (granulometry and organic matter content), the chemical parameters of interstitial water (salinity, pH, and dissolved oxygen), and the processes coastal areas (waves and tides).To achieve this goal, the following objectives are established: to determine, by remote sensing and geoprocessing, the geometry and spatial distribution of estuarine morphological features; in these features study the biogenic sedimentary structures, through neoichnological characterization (bioturbation index and ichnotaxonomic and ethological characterization) and, when possible, indicate the producing organism; to characterize the pattern of variation of textural (granulometric and organic matter content) and chemical attributes of interstitial water (salinity, ph and dissolved oxygen) for each morphological element associated with the occurrence of biogenic structures; to compare the set of morphological, neoichnological and physicochemical characterization results of sediments and interstitial water for the areas under study in order to discuss the occurrence, distribution and degree of preservation of biogenic structures and verify possible correlations with factors of sedimentary dynamics. This type of study has great potential to contribute to discussions on the calibration of paleoecological interpretation and validation of the occurrences of biogenic sedimentary structures in different environments of estuarine sedimentation. (AU)