Browsing by Author "Nannini, Matteo"
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- Positive species interactions structure rhodolith bed communities at a global scalePublication . Bulleri, Fabio; Schubert, Nadine; Hall‐Spencer, Jason M.; Basso, Daniela; Burdett, Heidi L.; Francini‐Filho, Ronaldo B.; Grall, Jacques; Horta, Paulo A.; Kamenos, Nicholas A.; Martin, Sophie; Nannini, Matteo; Neves, Pedro António Nobre Soares Pinto das; Olivé, Irene; Peña, Viviana; Ragazzola, Federica; Ribeiro, Cláudia; Rinde, Eli; Sissini, Marina; Tuya, Fernando; Silva, JoãoRhodolith beds are diverse and globally distributed habitats. Nonetheless, the role of rhodoliths in structuring the associated species community through a hierarchy of positive interactions is yet to be recognised. In this review, we provide evidence that rhodoliths can function as foundation species of multi-level facilitation cascades and, hence, are fundamental for the persistence of hierarchically structured communities within coastal oceans. Rhodoliths generate facilitation cascades by buffering physical stress, reducing consumer pressure and enhancing resource availability. Due to large variations in their shape, size and density, a single rhodolith bed can support multiple taxonomically distant and architecturally distinct habitat-forming species, such as primary producers, sponges or bivalves, thus encompassing a broad range of functional traits and providing a wealth of secondary microhabitat and food resources. In addition, rhodoliths are often mobile, and thus can redistribute associated species, potentially expanding the distribution of species with short-distance dispersal abilities. Key knowledge gaps we have identified include: the experimental assessment of the role of rhodoliths as basal facilitators; the length and temporal stability of facilitation cascades; variations in species interactions within cascades across environmental gradients; and the role of rhodolith beds as climate refugia. Addressing these research priorities will allow the development of evidence-based policy decisions and elevate rhodolith beds within marine conservation strategies.
- Withstanding the heat: resilience of free-living coralline algae to marine heatwavesPublication . Nannini, Matteo; Cerpelloni, Martina; Gaspar, Tainá L.; Peña, Viviana; Tuya, Fernando; Peñas, Julio; Rio, Jesús del; Vieira Mourato, Carolina; Silva, João; Santos, Rui; Ragazzola, Federica; Olivé, Irene; Schubert, NadineMarine heatwaves (MHWs) can severely impact benthic ecosystems, driving major ecological shifts. As they become longer, more frequent, and intense, MHWs are emerging as a dominant threat to marine biodiversity. Yet, their potential effects on coralline algal beds (CABs, including rhodolith beds), habitats of critical ecological importance, remain largely unknown. This study investigated the physiological responses of three rhodolith species (Lithothamnion cf. valens, Lithothamnion sp., Lithophyllum incrustans), which dominate the community of a Mediterranean CAB, to an experimentally simulated ecologically relevant scenario of two consecutive summer MHWs. Species responses in key physiological processes, photosynthesis, respiration, and calcification, were assessed before, during, and after the heatwave events. Overall, temperature increases had minor effects on photosynthesis and respiration, while calcification responses to MHWs were more pronounced and speciesspecific. Significant declines were observed in light calcification of L. incrustans during the first MHW, and in dark calcification of all three species, with L. incrustans and L. cf. valens responding during the first and second MHWs, respectively. Lithothamnion sp. exhibited some minor effects on light calcification and a significant shift toward carbonate dissolution in darkness during the first MHW, which reversed over time. Despite these effects, all species fully recovered by the end of the experiment, and the stronger impact of the first MHW suggests a potential priming effect that may enhance tolerance to subsequent heat events. These findings demonstrate rhodoliths’ overall capacity to withstand MHWs, while highlighting the role of species-specific responses in shaping the net carbonate balance of CABs under future climate scenarios.