Struttura dei popolamenti meiobentonici nella zona intertidale dell'Alto Adriatico a differenti gradi di antropizzazione

The present work is part of the European project THESEUS (Innovative technologies for safer Europeans coasts in a changing climate). The main goals are to provide adequate integrated methodologies for strategic planning of sustainable coastal defence. The present study investigates the structure and composition of meiobenthonic populations of the intertidal zone in four beaches along the Northern Adriatic coast of Emilia Romagna: Lido di Spina, Bellocchio, Lido di Dante e Cervia. The four sites are different for the level of human impacts and for the different management interventions against coastal erosion. The analysis of biotic and abiotic variables revealed different responses due mainly to site-specific characteristics of the investigated sites, in particular as regards the site of Bellocchio. The growing interest in ecosystems of sandy beaches has recently highlighted the importance of the ecological role of meiofauna, emphasizing the need to develop studies aimed to conservation as well as to the use of these organisms as descriptors of the environmental status. The present study showed that the response of the organisms of meiofauna was highly sensitive to the specific environmental conditions of the four sites considered. Therefore it appears to be possible to consider the response of meiofauna to environmental and anthropogenic stressors as supplementary information to the responses of macrobenthic communities, which have been, until now, widely recognized and used as syncretic indicators of the ecosystem status.

Analysis of the relationships between Spartina maritima and nutrient enrichment in North Adriatic salt marshes

Salt marshes are coastal ecosystem in the upper intertidal zone between internal water and sea and are widely spread throughout Italy, from Friuli Venezia Giulia, in the North, to Sicily, in the South. These delicate environments are threatened by eutrophication, habitat conversion (for land reclaiming or agriculture) and climate change impacts such as sea level rise. The objectives of my thesis were to: 1) analyse the distribution and biomass of the perennial native cordgrass Spartina maritima (one of the most relevant foundation species in the low intertidal saltmarsh vegetation in the study region) at 7 sites along the Northern Adriatic coast and relate it to critical environmental parameters and 2) to carry out a nutrient manipulation experiment to detect nutrient enrichment effects on S. maritima biomass and vegetation characteristics. The survey showed significant differences among sites in biological response variables - i.e., live belowground, live aboveground biomass, above:belowground (R:S) biomass ratio, % cover, average height and stem density – which were mainly related to differences in nitrate, nitrite and phosphate contents in surface water. Preliminary results from the experiment (which is still ongoing) showed so far no significant effects of nutrient enrichment on live aboveground and belowground biomass, R:S ratio, leaf %Carbon, average height, stem density and random shoot height; however, a significantly higher (P=0.018) increase in leaf %Nitrogen content in treated plots indicated that nutrient uptake had occurred.

The effect of temperature on pressure tolerance of the shallow-water shrimp Palaemon serratus

Tolerance to low temperature and high pressure may allow shallow-water species to extend bathymetric range in response to changing climate, but adaptation to contrasting shallow-water environments may affect tolerance to these factors. The brackish shallow-water shrimp Palaemon varians demonstrates remarkable tolerance to elevated hydrostatic pressure and low temperature, but inhabits a highly variable environment: environmental adaptation may therefore make P. varians tolerances unrepresentative of other shallow-water species. Critical thermal maximum (CTmax), critical hydrostatic pressure maximum (CPmax), and acute respiratory response to hydrostatic pressure were assessed in the shallow-water shrimp Palaemon serratus, which inhabits a more stable intertidal habitat. P. serratus’ CTmax was 22.3°C when acclimated at 10°C, and CPmax was 5.9, 10.1, and 14.1 MPa when acclimated at 5, 10, and 15°C respectively: these critical tolerances were consistently lower than P. varians. Respiratory responses to acute hyperbaric exposures similarly indicated lower tolerance to hydrostatic pressure in P. serratus than in P. varians. Contrasting tolerances likely reflect physiological adaptation to differing environments and reveal that the capacity for depth-range extension may vary among species from different habitats.