![]() Disruptions to extra- and intracellular acid-base balance have far-reaching consequences by compromising survival and adversely affecting ecologically relevant factors such as metabolism and feeding. A rise in intracellular H + can disrupt key biological processes such as metabolism, protein synthesis, ion-regulation, and cell volume control ( Whiteley, 1999). OA causes an increase in CO 2 in the haemolymph (extracellular compartment), which also enters the intracellular space. The most immediate physiological responses to ocean acidification (OA) in marine crustaceans are best described by acid–base adjustments ( Pane and Barry, 2007 Pörtner et al., 2010 Whiteley, 2011). High CO 2 has been reported to negatively impact various physiological processes, including growth ( Walther et al., 2010), survival ( Melzner et al., 2009), development ( Walther et al., 2010 Schiffer et al., 2013), immune response ( Meseck et al., 2016), chemoreception ( de la Haye et al., 2012), and swimming performance ( Dissanayake and Ishimatsu, 2011). Studies of physiological responses of crabs exposed to elevated pCO 2 ( Pane and Barry, 2007 Spicer et al., 2007 Fehsenfeld et al., 2011) have identified a wide range of responses ( Kroeker et al., 2010). Therefore, it is of great ecological and economy significance to study the predatory behavior and physiological responses of crabs under global change scenario. In spite of its economic and ecological importance, the information on the effect of environmental stressors such as seawater pH on crab predation behavior and physiological responses is limited. Crabs have specific feeding habits, and their diets contain many molluscs in coastal and shallow waters. A good knowledge of predation behavior is essential to understand the predator–prey interactions as well as consequences on the food chains ( Elner and Hughes, 1978). Predation is considered as a significant evolutionary and ecological factor influencing the activity and life style of individuals and the structure and composition of communities ( Lima and Dill, 1990). These results are discussed in the context of how elevated pCO 2 may impair the competitiveness of brown crabs in benthic communities. Elevated pCO 2 affected feeding performance negatively and prolonged foraging periods. In conclusion, elevated pCO 2 caused crab metabolic rate to increase at the expense of SDA. PCA results revealed a positive relationship between feeding/SDA and pH, but negative relationships between the length of foraging periods and pH. Again, a two-week recovery period was not sufficient for feeding behavior to return to control values. Under high CO 2, crabs fed on smaller sized mussels than under control CO 2 food consumption rates were reduced foraging parameters such as searching time, time to break the prey, eating time, and handling time were all significantly longer than under control CO 2, and prey profitability was significantly lower than that under control conditions. Conversely, SDA was significantly reduced under high CO 2 and did not return to control levels during recovery. Compared to the initial control CO 2 conditions, the SMRs of CO 2 exposed crabs were not significantly increased, but increased significantly when the crabs were returned to normal CO 2 levels. Standard metabolic rate (SMR), specific dynamic action (SDA) and feeding behavior of the crabs were investigated during each experimental period. ![]() Following 54 days of pre-acclimation to control CO 2 levels (360 μatm) at 11☌, crabs were exposed to consecutively increased oceanic CO 2 levels (2 weeks for 12 μatm, respectively) and subsequently returned to control CO 2 level (390 μatm) for 2 weeks in order to study their potential to acclimate elevated pCO 2 and recovery performance. Therefore, we examined the effects of simulated future elevated pCO 2 on feeding behavior and energy metabolism of the brown crab Cancer pagurus. ![]() Elevated pCO 2 may affect metabolism, feeding, and energy partition of marine crabs, and thereby affect their predator-prey dynamics with mussels. Marine animals may make physiological and behavioral adaptations to cope with OA. 4International Research Center for Marine Biosciences at Shanghai Ocean University, Ministry of Science and Technology, Shanghai, ChinaĪnthropogenic climate change exposes marine organisms to CO 2 induced ocean acidification (OA).3Department of Integrative Ecophysiology, Alfred-Wegener-Institute, Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany.2National Demonstration Center for Experimental Fisheries Science Education, Shanghai Ocean University, Shanghai, China.1Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Shanghai Ocean University, Ministry of Education, Shanghai, China.Youji Wang 1,2,3,4, Menghong Hu 1,2,3*, Fangli Wu 1,2, Daniela Storch 3 and Hans-Otto Pörtner 3 ![]()
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