Coupled changes in pH, temperature and dissolved oxygen impact the physiology and ecology of herbivorous kelp forest grazers

Understanding species’ responses to upwelling may be especially important in light of ongoing environmental change. Upwelling frequency and intensity are expected to increase in the future, while ocean acidification and deoxygenation are expected to decrease the pH and dissolved oxygen of upwelled waters. However, the acute effects of a single upwelling event and the integrated effects of multiple upwelling events on marine organisms are poorly understood. Here, we use in situ measurements of pH, temperature, and dissolved oxygen to characterize the covariance of environmental conditions within upwelling-dominated kelp forest ecosystems. We then test the effects of acute (0-3 days) and chronic (1-3 month) upwelling on the performance of two species of kelp forest grazers, the echinoderm, Mesocentrotus franciscanus, and the gastropod, Promartynia pulligo. We exposed organisms to static conditions in a regression design to determine the shape of the relationship between upwelling and perf...