1. Anthropogenic and natural impacts in the marine area of influence of the Grijalva – Usumacinta River (Southern Gulf of Mexico) during the last 45 years.
- Author
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Machain-Castillo, M.L., Ruiz-Fernández, A.C., Alonso-Rodríguez, R., Sanchez-Cabeza, J.A., Gío-Argáez, F.R., Rodríguez-Ramírez, A., Villegas-Hernández, R., Mora-García, A.I., Fuentes-Sánchez, A.P., Cardoso-Mohedano, J.G., Hernández-Becerril, D.U., Esqueda-Lara, K., Santiago-Pérez, S., Gómez-Ponce, M.A., and Pérez-Bernal, L.H.
- Subjects
TRACE elements ,HEAVY metals ,WATERSHEDS ,ENVIRONMENTAL sciences ,DAM design & construction ,DINOFLAGELLATE cysts ,MARINE sediments - Abstract
The development of the Grijalva-Usumacinta river basin exerts modifications on its discharge area. A sediment core was studied to reconstruct environmental changes and trace element contamination status during the past 45 years.
210 Pb-derived mass accumulation rates indicate higher sediment input to the area since 1995, related to increased precipitation and floodings in the catchment area. Sediments show finer particles from the late 1970s on, likely related to dams construction upriver and/or land use changes. Heavy metal enrichment factors (EF < 2) suggest minimum contamination. Benthic foraminifera and redox-sensitive - elements (As, Ba, Co, Cr, Cu, Ni, Pb, V and Zn) indicate the sediments before 2000 were deposited under oxygenated conditions. Afterwards, environmental conditions changed and benthic foraminifera and dinocysts assemblages changed suggesting eutrophication and lower oxygen conditions during the last 20 years. Monitoring should be continued to assess eutrophication/hypoxic/pollution trends that could become deleterious to the marine biota. • Sediments from past 45 years record environmental changes in the marine area off the largest river in southern Gulf of Mexico • Mass accumulation rates indicate higher sediment input to the area since 1995. • Higher sediment input related to increased precipitation and flooding in Tabasco City and the catchment area. • Grain size variation reflects land use change and damming since the 1980s. • Benthic Foraminifera and Dinocysts indicate a process of eutrophication in bottom waters during the last 20 years. [ABSTRACT FROM AUTHOR]- Published
- 2020
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