Synergistic effects of temperature and hypoxia on the chemical perception of a tidepool predator (Carcinus maenas)

Abstract

Climate change has had a major impact on the marine environment over recent decades. Seawater temperature has increased rapidly and under the most pessimistic IPCC projections is set to increase much further by the end of the century (2100). Different climatic stressors can act together on ecosystems, negatively affecting the maintenance of communities of marine organisms. Early critical changes are expected for coastal environments which are naturally subjected to daily and seasonal variation in temperature, salinity, oxygen and pH. Increases in temperature cause a decrease in the oxygen solubility of the water which can contribute to hypoxic conditions in restricted environments such as tidal pools. The relationship between prey and predator may be influenced by these changes, since both may have difficulties in detecting chemical signals in situations where there is an association between different stressors. When multiple stressors act together, synergistic, additive, antagonistic and cross-tolerance effects can occur. Thus, it is important to investigate the magnitude of the interference of the main abiotic variables in the intertidal zone, considering the context of climate change. The present study aims to test the effect of the interaction between temperature and hypoxia. The following hypothesis will be tested: The synergistic effect of temperature and hypoxia decreases the chemical perception of the predator crab Carcinus maenas within tidal pool. We will use the average rate of change of temperature and dissolved oxygen in UK tidepools to assess and categorize crab motivation to forage in tidal pools with and without chemical cues from a gastropod. We expect that the crab will not be able to identify chemical cues of a prey in a scenario of high temperature and hypoxia, which could negatively affect their ecological functions in the tide pools. (AU)