Reconstructing the history of environmental impact in a tropical mangrove ecosystem: A case study from the Suape port-industrial complex, Brazil

Abstract

Mangrove ecosystems can record biogeochemical and sedimentary signatures in their stratigraphic column. This study examines a mangrove sediment core to evaluate the potential environmental impact of a large-scale port-industrial construction in a tropical lagoonal–estuary near Recife, NE Brazil. Here, we measure sediment accretionrate (SAR), carbon and nitrogen stable isotopes (δ13C and δ15N), total organic matter (TOM), total nitrogen (TN), total organic carbon (TOC), and carbonate content (CaCO 3) to determine the impact of Suape’s Port-Industrial Complex in the adjacent estuarine system. We identify a high SAR (1.37 cm yr −1) and propose three main depositional phases in the 82 cm sediment core. The first phase (circa 1956–1973) corresponds to the period prior to the installation of the Suape port complex, where the sediments are characterized by containing sand and organic material derived from terrestrial sources. The second phase (c. 1976–1986) shows signatures that reflect the installation of the Suape port complex and the intensification of the sugarcane monoculture in the catchment area. This phase shows an increase of mud and carbonate content, interpreted as a predominance of marine sediment source due to the morphological changes along the estuary. The third and final phase (c. 1986–2015) contains fluctuating results, reflecting an increase of land use, but not as intense as the period after the installation of the port complex (phase 2). Our results show a biogeochemical and sediment signature shifts directly related to anthropogenic impacts and natural factors. Overall, this study reveals a shift in the sediment sources and composition in the Suape estuarine system as a consequence of human development adjacent to estuarine areas and the resilience of mangrove ecosystems to adapt to anthropogenic impact.