Coping with environmental change: a physiological perspective
Marine invertebrates are being influenced to an increasing degree by anthropogenic inputs into aquatic habitats where they may be already exposed to wide ranging and highly fluctuating changes in natural environmental factors (pH, temperature, salinity and oxygen levels). Physiological studies are a means of investigating the most immediate responses of aquatic invertebrates to physical changes in their environment. They can inform on the mechanisms used to maintain homeostasis in the face of change, and can be used to explain tolerance limits and capacities for compensation. Collectively these studies increase our understanding of the potential for individuals and species to survive change in order to reproduce resulting in the next generation. They can also help to identify general patterns in compensatory capacities and therefore tolerance to change between and within species, and across spatial and temporal scales. This talk will focus on the diversity of physiological responses shown by decapod crustaceans (crabs and lobsters) by first considering early experiments on acute exposures to hypoxia, and changes in salinity and pH levels. Attention will then turn to longer-term, chronic exposures, where it has been possible to investigate some of the consequences of the ability to adjust physiologically to environmental change in terms of performance. As we are now beginning to appreciate that aquatic environments are subject to simultaneous changes in physical variables, the combined effects of both salinity reduction and pH change will be considered linking contemporary studies to those conducted over 20 years ago, and providing some information that will help towards our understanding of whether decapod crustaceans are likely to survive climate change.