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Global warming and Marine Heat Waves (MHWs) are having large-scale impacts on the seagrasses and their effects on the Mediterranean endemic Posidonia oceanica need to be properly defined. This research aimed to sharpen the knowledge on P. oceanica response to the warming by correlating the shoot morphology and the productivity of the seagrass to temperature conditions and MHW occurrence. Two correlative studies, along a Mediterranean temperature range (sites at the same latitude), were conducted: one explored the associations of summer 2021 Sea Surface Temperature (SST) and MHWs on P. oceanica morphology and the other used a reconstruction technique (lepidochronological analysis) to relate past temperature conditions and MHW occurrence to proxies of seagrass productivity for the corresponding periods. The results showed that the mean summer temperature affected the P. oceanica leaf necrosis and that MHWs occurrence changed the morphology of the plant by lowering the leaf area and increasing leaf necrosis. Interesting results were also found relating the past thermal environment, since rhizome biomass has been negatively affected by the number of MHWs and rhizome length by the temperature range. This research provides fundamental insights about P. oceanica changes linked to warming and MHWs, identifying the potential plant indicators assisting future experimental and modelling studies. To the best of our knowledge, this is the first time a reconstruction technique is used to evaluate the effects of past MHWs on the morphology and productivity of a plant species.

The common sole, Solea solea, is one the most important commercial species in Europe and, within the Mediterranean, the Adriatic basin is the most crucial area for its production. Although the species is overexploited in the basin, data on its trophic ecology are fragmentary, even though this is one of the most important features within the Ecosystem Approach to Fishery. Here, we analysed temporal variations in the feeding ecology of the species by using an integrated approach of stomach contents and stable isotope analyses coupled with the analysis of some condition indices such as the gonadosomatic and the hepatosomatic indices. Changes in diet and trophic level across the years in adult females were clearly linked to the different energetic requirements facing reproduction. Temporal changes throughout the year were mainly related to changes in food availability. This study confirms the opportunistic behaviour of this benthophagous species and its role as a mesopredator, opening new perspectives for further investigations on the effects of the overexploitation of this important fishery resource on the marine trophic web.