Effects of ocean acidification and change of temperature and salinity on physiology of the fiddler crabs: a study in laboratory

Abstract

We aim to evaluate in laboratory the aspects of the physiology of marine crustaceans in the face of future climate change scenarios: ocean acidification and temperature and salinity alterations in consequence of rising sea level and/or increased rainfall. Although physiological systems keep internal environment reasonably constant under ideal conditions of pH, temperature, salinity, etc., suboptimal levels of these environmental variables may disrupt basic chemical reactions and cause alterations to physiological functions. We propose to evaluate in laboratory the synergetic effect of climate changes IPCC forecasts (2013) upon aspects of the physiology of crabs of the genus Uca collected in the Ecological Station Juréia-Itatins. The place has great biodiversity of decapods that occupy intertidal areas, rocky shores, mangroves and are subjected to floods resulting from rising sea level that may cause salinity alterations. The species chosen, Uca vocator and Uca mordax, are representative of the place and possible indicators for climate changes due to their sensibility to abiotic alterations such as population density which seasonally varies and distribution due to salinity. Physiological mechanisms will be investigated in animals exposed for five days to 40 treatments resultant of the combination of different pH levels (8.0 and 7.2), temperature (20, 25, 30 e 40oC) and salinity ( 25, 30, 35, 40 and 45). Metabolism, osmoregulation, ammonia excretion, oxidized energy substrate, haemolymph glucose concentration, hepatosomatic and gonadosomatic indices and energetic content of hepatopancreas and gonads will be investigated. The knowledge concerning the effects of climate changes upon the physiology of marine animals is an important strategy to know the vulnerability level of the species and the impact of these variations on the biodiversity of fiddler crabs. (AU)