Warning of warming limpets: sea temperature effects upon intertidal rocky assemblages

Limpets (Patella spp.) are marine gastropods that inhabit rocky shores along the coasts of Europe, the Mediterranean, Macaronesia and the north-west coast of Africa. Being considered key species, limpets have an important role regulating algal assemblages in coastal communities. The goal of this work was to evaluate the influence of sea temperature on the respiration rate of four limpet species occurring in mainland Portugal, in line with predictions from the metabolic theory of ecology. The individuals were collected from rocky shores in Portugal and exposed to sea temperatures ranging from 6-28 degrees C for respiration rate assessments. Following the estimation of the relationship between oxygen consumption and temperature the activation energy was calculated. In parallel, low and high thermal thresholds were determined for three of the species. The results indicated that P. ulyssiponensis oxygen consumption increased linearly with sea temperature and the remaining species presented the same tendency. The values of activation energy ranged between 0.33-0.76 eV. For P. ulyssiponensis, the highest activation energy indicated that this species is more sensitive to temperature variations while for the tested temperatures it presented a higher thermal tolerance limit than the other species. Such findings indicate that P. ulyssiponensis is the most susceptible of these species to climate change, in line with the tolerance-plasticity trade-off hypothesis. This work provides a good starting point for understanding the effect of sea temperature on oxygen consumption in Patella spp. and for comprehending sensitivity of limpets to temperature increases under future climate change scenarios.