Dr. Richelle Tanner
Climate change ecophysiology.
Climate change ecophysiology.
This page is framed for public communication purposes. Please see CURRENT PROJECTS for specific research topics.
What is it?
Breaking it down word-by-word, "ecophysiology" is really two topics in one. Physiology is the study of how the body operates, and responds to the environment. It is the physical expression of the relationship between selection and the environment! Ecophysiology refers to a specific subset of physiology where we look at how animal (or plant) physiology is changed by ecological and environmental relationships. Within these ecological and environmental relationships with animal physiology, I'm specifically interested in how climate change plays a role. If climate change is the "cause", the "effect" I'm interested in is physiology. I define climate change as any environmental phenomenon associated with the human-induced increase in carbon dioxide in the atmosphere. This includes environmental changes like rising average temperatures, ocean acidification, and increased frequency of extreme events (cold snaps, heat waves, flooding, hurricanes, etc.).
How do I study it?
Physiology has many methods in the toolbox, both in the lab and in the field. I track natural populations in the wild, I raise animals in the lab, and I use these animals to look at many levels of biological organization. This means I look at how often individuals reproduce, how they respond to climate change stressors in their swimming speed/muscle function/heart rate/etc., and what is happening at the biochemical level to proteins, genes, and potential modifiers of these. Through all of these methods, I can build a picture of how an animal may respond to certain environmental conditions during different parts of its life and through multiple generations of a species. I also use these findings to build predictive mathematical models of how ecological interactions and ecosystems in general will shift with changes in climate.
What ecological and evolutionary questions can I address?
As climate change is ongoing, there are so many opportunities to look forward to future shifts and also explore current physiological responses. My main focus currently is looking at how all of these physiological traits vary within a single species, so that we can better understand the available variation that selection can act upon when the environment changes. I can look at how these single species responses translate to ecological interactions - within a food web or ecosystem, species rely on each other to function properly. What happens when one or more has a change in their physiology and consequently their functioning within the ecosystem? I can also look at whether certain species are more likely to adapt to climate change because of evolutionary history. For example, species living in highly fluctuating environments might fare well in future fluctuating environments that we're expecting. Is physiological adaptation more likely for certain groups of species and why? Does this relate to patterns we've seen in the fossil record for the most successful taxa through major environmental changes?
An easy method to look at how sea hares respond to climate change stressors in foot muscle function. We raise animals in the lab at multiple temperatures representing different climate scenarios, and then test their response to heat waves by heating them until muscle function is lost. This is called the critical thermal maximum. When they lose muscle function, they can't eat or move around - they recover from this experiment fully, but this response tells us about how sea hares can stop functioning in their food web or ecosystem when heat waves strike.