Contents lists available at ScienceDirect Estuarine, Coastal and Shelf Science journal homepage: www.elsevier.com/locate/ecss Impacts of coseismic uplift caused by the 2010 8.8 Mw earthquake on the macrobenthic community of the Tubul-Raqui Saltmarsh (Chile) Natalia Sandoval a , Claudio Valdovinos Zarges a,* , Oyanedel Juan Pablo b , Daniela Vásquez c a Departamento de Sistemas Acuáticos, Facultad de Ciencias Ambientales y Centro EULA, Universidad de Concepción, Barrio Universitario s/n, 4070409, Concepción, Chile b Biomaconsultores, Francisco Bilbao 3792, Las Condes, 7550606, Santiago, Chile c Escuela de Ciencias Ambientales, Facultad de Recursos Naturales, Universidad Católica de Temuco, Prieto Nte 371, 4781148, Temuco, Chile ARTICLE INFO Keywords: Coseismic uplift Macroinvertebrates Sediment Water quality Perturbation Wetland ABSTRACT Coseismic uplift, as caused by high-magnitude earthquakes, can modify shoreline morphologies and the func- tioning of coastal wetlands. This phenomenon occurred with the 8.8-Richter scale earthquake that affected central-south Chile in 2010. The recorded coseismic uplift was 1.6 m.a.s.l. significantly changed the Tubul-Raqui Saltmarsh. The most important impact of this event was decreased marine intrusion, which, in turn, led to desiccation within the saltmarsh and, consequently, the death of aquatic organisms. This study recorded the effects that physical/chemical changes in water quality and the sedimentary environment had on the macro- benthic community (> 500 μm) 2, 6, and 10 months after the uplift event, with data compared against historical records. Non-metric multidimensional scaling evaluated changes in the biological community, while principal components analysis was used to assess environmental changes. Both matrices were adjusted through correla- tion. Significant pre-versus post-earthquake modifications were found at sites closest to the estuary inlet. The most significantly affected macroinvertebrate was Paracorophium hartmannorum. The most tolerant taxa to en- vironmental perturbations (i.e., Diptera, Annelid, and Polychaeta) surpassed pre-earthquake abundance records after just ten months, whereas the most sensitive taxa were not found after the earthquake. Most (81.8%) variables of water quality (i.e., total suspended/inorganic/organic solids and chlorophyll-a), as well as the se- dimentary environment (i.e., sediment redox potential, fine fraction, and area of emerged bed), were sig- nificantly correlated with the macrobenthic community. The results of this study show the resilience capacity of important components of a saltmarsh after a major natural disturbance. 1. Introduction Coastal countries close to active subduction zones of tectonic plates are frequently affected by earthquakes and tsunamis (Scholz, 1998; McCaffrey et al., 2007; Castaños and Lomnitz, 2012; Katsumata, 2017). These events can result in deformations of the continental shelf, such as coseismic uplift (Quezada et al., 2012), which consists in a lifting of the continent, sometimes up to 2 m in height. In the last 60 years, this phenomenon has been scarcely described, but records do exist for the following earthquakes: Chile in 1960 (Barrientos et al., 1992), 1985 (Castilla and Oliva, 1990), 1995 (Ortlieb et al., 1996), and 2010 (Melnick et al., 2012); Alaska, USA in 1964 (Cohen, 1996); Mexico in 1985 (Bodin and Klinger, 1986); Papua New Guinea in 1992 (Pandolfi et al., 1994); California, USA in 1992 (Carver et al., 1994); Algeria in 2003 (Meghraoui et al., 2004); Sumatra, Indonesia in 2004 and 2005 (Tobita et al., 2006); and Kaikoura, New Zealand in 2016 (Shi et al., 2017). Along the western limit of South America, coseismic uplifting is caused by the Nazca Plate, which is subducting below the South America Plate (Cahill and Isacks, 1992; Quezada et al., 2012; Briggs, 2016). Following earthquakes with a greater than 7.5 moment magni- tude (Mw), large variations have been recorded for the coastal mor- phology of this region, changes that consequently have significant im- pacts on coastal ecosystems such as estuaries, marshes, and coastal lagoons, among others (Castilla et al., 2010; Jaramillo et al., 2012). On February 27th, 2010, south-central Chile was hit by an 8.8 Mw earthquake and subsequent tsunami (Vargas et al., 2011; Martínez et al., 2012; Quezada et al., 2012). In areas close to the epicenter (Fig. 1), the continental shelf uplifted more than 2 m, causing the death of nearly all intertidal organisms (Farías et al., 2010). Also affected was the Tubul-Raqui Saltmarsh, located 137.4 km from the rupture zone (Fig. 1). This saltmarsh was uplifted 1.6 m above sea level (m.a.s.l.), https://doi.org/10.1016/j.ecss.2019.106278 Received 22 January 2018; Received in revised form 27 June 2019; Accepted 1 July 2019 * Corresponding author. E-mail address: cvaldovi@udec.cl (C.V. Zarges). Estuarine, Coastal and Shelf Science 226 (2019) 106278 Available online 02 July 2019 0272-7714/ © 2019 Published by Elsevier Ltd. T