Fouling community shows high resistance and metabolic resilience towards experimental high intensity heatwave

Climate change is predicted to increase the prevalence of marine heatwaves with an increase in heatwave frequency and intensity. While some studies have shown the effect of marine heatwaves in warm temperate climates and the effect of overall higher temperature in warm and cold temperate climates, it is yet not entirely understood how heatwaves impact marine urban communities in cold temperate climates. As thermal resistance might be related to selective pressures and acclimation, it seems reasonable to assume that they may have a strong impact on local fauna and flora. In the present study, we simulated an in situ high amplitude heatwave and observed the community structure and the metabolism of Bugula neritina at two time-steps after the heatwave and compared them to control communities and individuals. Contrary to our expectations, the community structure remained vastly unaffected, as did the total metabolome of B. neritina . This shows that the community was able to resist the disturbance of the heatwave. Bugula neritina additionally showed a certain metabolic resilience as the already minor differences in the metabolome between control and the heatwave treatment diminished even further between the tested time steps. • We simulated a heatwave (8d; max. 5 C above threshold) in situ on port communities. • Community structure was unaffected showing strong resistance to the disturbance. • The metabolome of Bugula neritina was also unaffected and equal to control. • While some molecules varied after the heatwave their number diminished later. • We conclude on high community resistance and metabolic resilience of B. neritina .