Meeting Abstract
Heterogeneity of abiotic environmental conditions manifests at a variety of spatial scales, and organisms may experience substantially different conditions compared to neighbors even over small distances of a few body lengths. The rocky intertidal zone represents an extreme case of such micro-scale variation. Here, we present field-based, continuous measurements of live mussel (Mytilus californianus, n = 30) body temperatures, valve gaping behavior, and body orientation from three micro-sites on a rocky shoreline: one at the upper limit of the mussel zone, one near the lower limit of this zone, and a third mirco-site continuously submerged in a tidepool. These data were obtained with a custom, modular data acquisition system on an Arduino-based platform. As expected, differences in shore height of only a meter lead to drastically different mean thermal histories and opportunities for feeding or recovery from thermal stress events. On the scale of centimeters within a single mussel bed, we also observe a wide range of maximum temperatures achieved by individual mussels of the same body size (up to 13.75 °C difference during one low tide). An individual’s body temperature depends on its position in the bed and its body orientation. Notably, body temperatures of live mussels can depart substantially from thermal mimics deployed in the same bed. These data provide a comprehensive record of micro-scale spatial and temporal variation in thermal history experienced by organisms within a single population. When coupled with measures of physiological status, these field measurements will allow us to examine the contributions of spatial variation to patterns of survival, growth, and, ultimately, community structure up and down the shore.
