Ecological Indicators 46 (2014) 232–239 Contents lists available at ScienceDirect Ecological Indicators jo ur nal ho me page: www.elsevier.com/locate/ ecolind Physiological and biochemical thermal stress response of the intertidal rock goby Gobius paganellus Diana Madeira a,∗ , Vanessa Mendonc ¸ a b , Marta Dias b , Joana Roma b , Pedro M. Costa c , Mário S. Diniz a , Catarina Vinagre b a REQUIMTE, Departamento de Química, Centro de Química Fina e Biotecnologia, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal b Centro de Oceanografia, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, 1749-016 Lisboa, Portugal c IMAR – Instituto do Mar, Departamento de Ciências e Engenharia do Ambiente, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal a r t i c l e i n f o Article history: Received 26 January 2014 Received in revised form 5 May 2014 Accepted 23 June 2014 Keywords: Gobius paganellus Climate change Critical thermal maximum Hsp70 Ubiquitin a b s t r a c t The intertidal habitat is characterized by environmental conditions with steep gradients. Thus, inhabiting communities have long served as models in stress research. Moreover, several studies have reported their vulnerability to climate change and consequent distribution shifts (up to 50 km per decade) and abundance changes. The aims of this study were to test the effects of temperature on the rock goby Gobius paganellus in order to understand its resistance to environmental fluctuations (e.g. low tide events, heat waves) and gain insights into its vulnerability to climate change. The upper thermal limit for the species was estimated through the critical thermal maximum (CTMax). Individuals were exposed to a temperature increase ramp of 1 ◦ C h -1 . Two thermal stress biomarkers (hsp70 and total ubiquitin) were quantified in the gill, muscle and liver via enzyme linked immunosorbent assays. Results showed no increases in hsp70 in neither of the organs in response to temperature but ubiquitin levels were elevated in liver at 30 ◦ C. Both biomarker basal levels were higher in gills, followed by liver and finally muscle. The results indicate that the species, although adapted to the intertidal environment, can experience stress at high temperatures of 30 ◦ C and above. Therefore, it may be vulnerable to heat waves, especially occurring during low tides that coincide with the hottest hours of the day during summer, with adverse implications in a climate change scenario that predicts temperature rising and increasing (in length and frequency) periods of extreme heat. The present study also shows that different organs possess distinct heat stress thresholds and responses, hence the importance of multi-organ approaches in order to comprehend the full health status of the organisms following acute thermal challenge. © 2014 Elsevier Ltd. All rights reserved. 1. Introduction The intertidal habitat is characterized by environmental con- ditions with steep gradients (Menge and Branch, 2001; Tomanek and Helmuth, 2002; Hofmann, 2005) that can become harsh to its inhabiting communities. These habitats are in between the terres- trial and marine realms, imposing the conditions of aquatic and aerial regimes on its living organisms (Helmuth et al., 2006). Several environmental factors are of extreme importance in these habi- tats, such as solar radiation, wind, wave exposure and temperature ∗ Corresponding author. Tel.: +351 21 2948500; fax: +351 212948554. E-mail address: dianamadeira@netcabo.pt (D. Madeira). among others (Bell, 1995; Helmuth, 1999; Stenseth et al., 2003). Temperature is of general importance as it affects marine life at sev- eral levels (Hochachka and Somero, 2002). It determines metabolic rates and reactions, behavioral responses (Mora and Ospina, 2001) and severely affects the performance of ectotherms (Porter and Gates, 1969). Additionally, it influences the organisms’ growth (e.g. Phillips, 2005), feeding (e.g. Sanford, 2002), reproduction (e.g. Philippart et al., 2003) and ultimately survival (Dallas and Rivers- Moore, 2012). Finally, temperature sets ecological patterns at the population and ecosystem level (Walther et al., 2002; Gaston, 2003; Helmuth et al., 2006). Considering this, intertidal organisms are subjected to environmental challenges and must possess certain adaptations in order to successfully colonize those habitats. Thus, these organisms have been widely used in stress research and may http://dx.doi.org/10.1016/j.ecolind.2014.06.029 1470-160X/© 2014 Elsevier Ltd. All rights reserved.