The herpacticoid copepod, Tigriopus californicus, has the potential to be a model organism for the study of environmental and ecological physiology. It inhabits tide pools high on the shore where input of fresh seawater is at best episodic. The temperature in these pools can vary by more than 20 degrees Celsius in a day, and the salinity can vary from nearly 0 psu after a rainstorm to nearly four times that of seawater after a long stretch of desiccation. To make the pools even more inhospitable, photosynthesis by microalga in the pools sucks up dissolved carbon dioxide during the day (resulting in an increase in pH and hypersaturation of dissolved oxygen) alternating with respiration at night (during which the pH sinks and the pools go anoxic).
To explore how Toigriopus survives (and even thrives) in this highly variable environment, Mark Denny is collaborating with Wes Dowd (Washington State University) to measure how the pools' various stressor combine to effect the copepod's physiology. This ambitious project will expose copepods to various combinations of stressors in the lab, measure the resulting functional attributes, and tie these measurements to field conditions.