1,721,115 research outputs found
Alpha and beta diversity in Mediterranean macroalgal assemblages: relevancy and type of effect of anthropogenic stressors vs natural variability
No full textDinamica di popolazione di una speciedel complesso Capitella capitata in un piccolo bacino salmastro dell’Isola d’Elba
No full textResistance of Posidonia oceanica seedlings to warming: Investigating the importance of the lag-phase duration between two heat events to thermo-priming
No full textThe increase of marine heat waves (MHWs) occurrence is exacerbated in Mediterranean Sea and temperature resilience-enhancing strategies on key species, such as the seagrass Posidonia oceanica, need to be investigated. “Priming” describes a stimulus that prepares an organism for an improved response to upcoming environmental changes by triggering a memory that remains during a lag-phase. The aim of this study, conducted in Sardinia (Italy), was to investigate whether the development of thermo-primed P. oceanica seedlings is affected by a field simulated MHW depending on the duration of the lag-phase. After the thermo-priming stimulus, seedlings had a 0, 7 or 14 days lag-phase and after that, for each lag-phase group, half of the seedlings experienced a simulated MHW (the other half served as controls). Some other seedlings did not experience either the priming stimulus or the lag-phase. Results did not show any evidence of a memory triggered by the priming stimulus, but they highlighted the importance of an acclimation phase before the highest temperature: seedlings that experienced a gradual increase of temperature had a higher number of leaves and shorter leaf necrosis length compared to seedlings that had a lag-phase between two heat events. Regardless the priming stimulus, MHWs slowed down the development of the leaf and root length. Considering the increase of temperature fluctuations, testing different intensities of priming and different length of lag-phase is necessary to provide information about the adaptive success of the species
Investigating on the occurrence of Paracentrotus lividus in rocky and Posidonia oceanica habitat
No full textDoes accessibility of locations interact with protection effect on shallow rocky habitats?
No full textStreblospio shrubsolii(Polychaeta:Spionidae)temporal fluctuations in size and reproductive activity
Full text linkTemporal fluctuations in size and reproductive activity of a Streblospio shrubsolii population were studied in a small brackish basin, to evaluate how these features influenced population dynamics and determine the persistence of this species in such an unstable environment. In the three study years, S. shrubsolii exhibited continuous reproduction from March to November but with two seasonal peaks in late spring and autumn. Larvae were lecithotrophic and developed between the female body and the tube wall. Individual fecundity showed significant differences between seasons, with trends coinciding with variations in mean female size. Changes in population size structure gave evidence that density fluctuations resulted mainly from recruitment during spring-early summer, or autumn. Potential larval production patterns peaked 1 or 2 months prior to periods of maximal abundance, and exhibited a progressive increase especially during the autumn of the study periods. Different life-history traits and different levels in reproductive activity were observed both on the temporal (study population) and spatial scale (other populations described) in S. shrubsolii. It is suggested that S. shrubsolii life- history flexibility may represent a successful way to maximize fitness in a fluctuating environmen
Response of the non-indigenous Calerpa racemosa (Forsskal) J. Agardh to the native seagrass Posidonia oceanica (L.) Delile: effect of density of shoots and orientation of edges of meadows
No full textDinamica di popolazione di Streblospio shrubsolii (Annelida: Polychaeta): fluttuazioni stagionali e attività riproduttiva
No full textWarming-induced flowering and fruiting in the seagrass Posidonia oceanica and uncertainties due to context-dependent features
No full textThis study explores the impacts of global warming on the reproductive efforts of Posidonia oceanica, a key seagrass species endemic to the Mediterranean Sea. By analyzing data from five areas in Sardinia in February 2023, we have investigated the relationship between thermal descriptors and P. oceanica flowering and fruiting variables. In fact, whether climate change has been affected the distribution of seagrasses by changing their reproductive efforts is still controversial and our findings contribute to this ongoing debate, highlighting a noticeable increase in reproductive events potentially affected by rising temperature. Overall, mean summer sea surface temperature (SST) was positively associated to inflorescence density, presence of living fruits and fruit size; living fruits and fruit size were also influenced positively by the maximum SST within 3 months before sampling (November–February). Both flowering and fruiting were negatively affected by the maximum SST within 1 month before inflorescence observation and mean winter SST, respectively, suggesting that P. oceanica reproductive effort depends on the duration and the temporal context in which the anomaly occurs. However, the high variability between meadows of the same area highlights the need of future studies to focus on the uncertainties related to local factors
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