Grant: Discovery Grants Program - Individual

Climate change and anthropogenic eutrophication have caused a considerable change in the characteristics of shallow coastal zones, leading to increases in the incidence of hypoxia and a rise in temperature. Crustaceans are among the most sensitive marine organisms to hypoxia, thus, knowledge of their physiological and behavioural responses will be invaluable when predicting long-term effects on benthic communities. Historically, when researchers carry out experiments animals are acclimated to new laboratory conditions for a number of weeks prior to experimentation. In addition, only one environmental variable is usually changed. However, nature does not exist in this controlled "black box" environment. Recent work from my lab suggests the environmental characteristics of most aquatic biomes are constantly changing. The typical lab-based acclimation regimes may be too controlled and even stressful for many organisms. The main focus of this research is to investigate how acclimation to more natural environmental regimes influences the physiology and behaviour of decapod crustaceans. In the first experimental series a variety of decapod species will be acclimated to cycling hypoxia/temperature combinations using a multi-stressor unit. Standard physiological and biochemical parameters will then be measured during exposure to combinations of hypoxia and temperature. A Loligo systems Shuttleboxr apparatus will be used to determine behavioural preferences and locomotor activity in response to hypoxia and temperature. Experiments will also be performed in the field. Data logging has become more refined in recent years and fine-scale changes in environmental parameters can now be recorded in situ. Animals will be maintained in mesh cages at various locales in the field while recording the physicochemical parameters. These field animals will be transferred to the lab for immediate assessment of physiological and behavioural responses to environmental change and compared to crustaceans acclimated to long-term stable conditions in the lab. Finally, while most physiological apparatus cannot be used in the field, miniaturized temperature/accelerometer tags that record heart rate are available. In these experiments large crustaceans implanted with heart rate loggers will be maintained in the field while monitoring environmental changes. These animals will then be brought into the lab where physicochemical parameters will be replicated to determine if the same patterns in heart rate and activity can be reproduced. These projects will provide training for a number of undergraduate and graduate students. The results of these projects should show if lab-based experiments accurately represent the responses of animals in the wild and may change the way we view and interpret experiments performed in controlled settings.