Marine Environmental Research 153 (2020) 104840 Available online 9 November 2019 0141-1136/© 2019 Elsevier Ltd. All rights reserved. Combined effects of warming and freshening on the physiological energetics of the edible whelk Trophon geversianus Camille D� etr� ee a, b , Alejandro Ortiz a, b , Jorge M. Navarro a, b, * a Instituto de Ciencias Marinas y Limnol� ogicas, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile b Centro FONDAP de Investigaci� on de Ecosistemas Marinos de Altas Latitudes (IDEAL), Universidad Austral de Chile, Valdivia, Chile ABSTRACT The interacting effects of climate change pressures and human use of natural resources are increasingly affecting marine biodiversity. Variations in key abiotic factors such as temperature and salinity may therefore negatively infuence marine organisms that are already threatened by intensive fsheries. Herein, we tested the hypothesis that future ocean warming and freshening will affect the ftness and survival of the overexploited snail Trophon geversianus in Southern Patagonia. To test this hypothesis, we investigated the effect of a 50 day incubation period of fve temperatures (1, 5, 9, 12 and 15 � C) and two salinities (25 and 30 psu), (which correspond to current and projected conditions for Antarctic and Sub-Antarctic regions), on the physiological energetics (ingestion rate, absorption effciency, oxygen uptake and scope for growth (SFG)) of the edible whelk T. geversianus. Our results showed no signifcant effects for salinity or the combination of temperature and salinity on T. geversianus bioenergetics. On the contrary, incubation at low temperatures (1 and 5 � C) was shown to affect the ingestion rate, absorption effciency, oxygen uptake and SFG for T. geversianus, whereas for specimens incubated at 12 and 15 � C, physiological rates remained similar to control. Our data suggests that T. geversianus might be robust to warming and future variations of salinity, but longer term experiments are needed to ensure that no reduction of performance will occur after an extended incubation time from an increase in temperature. 1. Introduction Global climate change is threatening biodiversity and will increas- ingly do so into the future. In the ocean, the variation of key abiotic factors such as temperature, pH and salinity are altering the physiology and phenology of a large diversity of organisms (Deutsch et al., 2015; Peck et al., 2009; Thomas et al., 2004). The oceans are heating up 40% faster than expected with recent studies suggesting a global increase of sea surface temperature of 1.5 � C by the end of the century (IPCC, 2014; Cheng et al., 2019; Zanna et al., 2019). Temperature is one of the most studied physical factors and plays a key role in both the performance and ftness of ectotherms, as their body temperature changes with the tem- perature of the surrounding environment (Sokolova and Lannig, 2008). In a warming ocean, the internal temperature of ectothermic organisms increases, in turn altering biochemical and metabolic rates. Hence, the resilience of marine ectotherms to global warming is mainly determined by their thermal tolerance, phenotypic plasticity, and in the longer term, their adaptive capacity (Huey et al., 2012). High latitudes are particularly sensitive to global warming and the pattern of increasing temperature is expecting to have a large impact in ice-covered regions (Constable et al., 2014; Shadwick et al., 2013; Swart et al., 2018). Recently, substantial increases in melting ice has led to an increase of freshwater inputs into the North Atlantic Ocean (Dickson et al., 2002), diminishing total alkalinity in seawater and contributing to carbonate under saturation (Manno et al., 2012). Changes in seawater salinity and carbonate saturation also affects the biological composition of marine invertebrates, especially marine ectotherms, which are stenohaline, and therefore exhibit a restricted salinity tolerance (Smyth and Elliott, 2016). Hence, ice-melt in high latitudes could affect marine ectotherms’ biological features such as growth, reproduction, larval recruitment and dispersal. The freshening in polar regions perfectly exemplifes how climate change encompasses a wide range of physical and chemical changes, that are likely to interact in a complex non-linear way (Kinne, 1964; Kroeker et al., 2017; Sokolova, 2013). To successfully assess the vulnerability of marine organisms to climate change and predict changes in species distribution, it is imperative to take into account the multi- plicity of climate change-induced pressures (Williams et al., 2008). For example, the combination of both increasing temperature and low salinity has been shown to decrease the oxygen saturation of the envi- ronment, impacting the survival and settlement of barnacle larvae of Balanus improvisus in the Baltic sea (Nasrolahi et al., 2016). More, when studying the effects of low salinity and warming on the invasive mussel Brachidontes pharaonis, Sar� a et al. (2008) observed a reduced scope for * Corresponding author. Instituto de Ciencias Marinas y Limnol� ogicas, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile. E-mail address: jnavarro@uach.cl (J.M. Navarro). Contents lists available at ScienceDirect Marine Environmental Research journal homepage: http://www.elsevier.com/locate/marenvrev https://doi.org/10.1016/j.marenvres.2019.104840 Received 16 August 2019; Received in revised form 14 October 2019; Accepted 8 November 2019