The rocky coastline of Calafuria, in the province of Livorno, served as a natural laboratory for a study conducted by the University of Pisa and the Scuola Superiore Sant’Anna to investigate how climate change is altering marine ecosystems. The research, published in Nature Communications, focused on how biofilm—a thin, living layer composed of microalgae and bacteria, essential to the health of rocky reefs—responds to air temperature variations.
Researchers carried out a field experiment by exposing the biofilm to two different warming regimes: one fixed warming condition and another characterized by fluctuating warming, simulating the increasingly unpredictable temperature patterns expected to become more frequent due to climate change. The results showed that fixed warming promoted the presence of species with overlapping functional traits—species capable of functionally compensating for each other under stress. This functional redundancy helped the biofilm better withstand extreme events. In contrast, fluctuating warming reduced diversity and favored fast-growing taxa capable of quickly recovering after a thermal shock but more functionally vulnerable over the long term.
The Calafuria area, near Livorno (photo), with its sandstone rock platforms exposed during low tide, provided an ideal setting to study marine biofilm under natural conditions. To simulate rising temperatures, the researchers used special metal chambers heated by small stoves and monitored heat variations using electronic sensors. An infrared camera was used to assess the biofilm’s chlorophyll levels, serving as an indicator of biomass. Furthermore, thanks to collaboration with the Institute of Life Sciences at Scuola Superiore Sant’Anna in Pisa, researchers conducted advanced DNA sequencing—similar to that used in human genomics—to determine the functions of different microbial species and how their genetic makeup influences their ability to respond to extreme events
“Climate change does not only manifest through rising average temperatures, but also through increasing thermal variability, with unpredictable swings between heat peaks and cooler periods,” explains Professor Luca Rindi of the University of Pisa, lead author of the study. “In a world that’s becoming hotter and more unstable, marine microorganisms might react faster to shocks but become more vulnerable when exposed to repeated extreme events. This study offers a window into the future, helping us understand how this crucial component of coastal ecosystems may respond to ongoing climate change.”
“The success of this collaboration once again underscores the strength of the Pisa university system,” adds Professor Matteo Dell’Acqua, Director of the Institute of Plant Sciences at Scuola Sant’Anna and co-author of the study. “Bringing together the unique expertise available in our region allows us to push the frontiers of research on climate change impacts.”
The University of Pisa played a central role in the research, particularly through its Department of Biology, where key authors including Professors Luca Rindi and Lisandro Benedetti-Cecchi conducted their work. The university also provided scientific and logistical support for designing and executing the field experiments and contributed to the ecological and microbiological data analysis through the Green Data Center.
The project received partial funding from the European ACTNOW program (Advancing understanding of Cumulative Impacts on European marine biodiversity, ecosystem functions and services for human wellbeing), which focuses on the cumulative impacts of climate change on marine ecosystems.
(Translated with the assistance of ChatGPT 4o)