Description: Seagrass is a foundation species within shallow water ecosystems because it provides habitat and food and thereby supports biodiversity. It has a function as atmospheric CO2 storage and improves the water quality by filtering nutrients (Greiner et al. 2013). Currently, seagrass meadows are facing multiple challenges such as ocean warming, reduced light caused by increasing nutrient input and more frequent disturbance events or direct anthropogenic impact (Unsworth et al. 2019). All these factors affect the performance of seagrass and thereby impair the ecosystem services seagrass meadows provide. This thesis represents a systematic review and meta-analysis of the physiological effects of temperature change on seagrass to provide a better understanding of the effect of rising temperatures on seagrass meadows worldwide. In this thesis, 766 papers were reviewed and a subsequent meta-analysis of 43 papers including 407 control-treatment temperature combinations matching the inclusion criteria were conducted. The log response ratio (lnR) was used for calculating the effect sizes, because it is more intuitive to interpret. Hedges’ g was further used to verify the results. It was tested for effects of the physiological parameters measured, the treatment type, the temperature direction, the experiment duration, the control temperature, latitude and longitude of the source population and the genus on relative seagrass performance (lnR). The key results of the meta-analysis showed that (I) plant physiological performance was reduced by an average of 39% by temperature change across all studies; (II) per 1°C experimental ocean warming a reduction in seagrass performance of 11% was observed; (III) the measured performance parameters (growth, biomass, photosynthesis and survival) showed differential susceptibility to warming, with survival being most affected and photosynthesis least affected; (IV) seagrass genera did not differ significantly in their response to experimental ocean warming but varied between locations. There was a strong geographic bias in this meta-analysis since most case studies were conducted in developed countries including Europe, the US and Australia. Thus, many species were underrepresented while also some climate conditions were not covered. Further, it was also not possible to make a statement about the recovery after experimental temperature stress had ceased, as there were too few studies focusing on recovery. Altogether, this thesis identified two profound knowledge gaps, which should be addressed by future studies. In conclusion, more frequent and intense heat waves are an increasing threat to seagrass meadows in the future. As seagrass provides important ecological services, it needs to be protected. It is particularly striking that every degree Celsius of temperature change matters for seagrass as it means a reduction in physiological and morphological performance, which is another indication that global warming should be kept below 2 degrees Celsius

Description: Modern digital scientific workflows - often implying Big Data challenges - require data infrastructures and innovative data science methods across disciplines and technologies. Diverse activities within and outside HGF deal with these challenges, on all levels. The series of Data Science Symposia fosters knowledge exchange and collaboration in the Earth and Environment research community.

Description: This article develops a sectoral approach to the analysis of global climate governance. This approach advances the assessment of global climate governance by focusing on complexes of intergovernmental and transnational institutions co-governing key socio-technical sectoral systems. The actual and potential contribution of these sectoral institutional complexes to advancing decarbonization can be assessed according to five key governance functions: (1) providing guidance and signal to actors, (2) setting rules to facilitate collective action, (3) enhancing transparency and accountability, (4) offering support (finance, technology, capacity-building), and (5) promoting knowledge and learning. On this basis, we can assess the potential of international cooperation to address the challenges specific sectoral systems face in the climate transition as well as the extent to which existing sectoral institutional complexes deliver on this potential. This provides a solid starting point for developing options for filling identified gaps and enhancing the effectiveness of global climate governance.

Description: Publications Office of the European Union, Luxembourg

Description: Published

Description: 7SR AMBIENTE – Servizi e ricerca per la società

Description: The steep walls of Chilean fjords are biodiversity hotspots and characterized by high precipitation rates, high river run-off and natural landslides with an inherent high sediment input. These sedimentation rates are likely to increase in the future due to expanding salmonid farming and coastal road construction. Caryophyllia huinayensis, is a Scleractinia, solitary cold-water coral (CWC) growing on steep slopes and overhanging portions of the fjord walls, which may indicate a sensitivity to sedimentation. However, actual data on the susceptibility to sediment of this CWC species is lacking. Furthermore, there is a deficit of information on juvenile CWC dealing with sedimentation stress, which is why this is the first study on this topic. The aim of this work was to investigate whether increased sediment concentrations affect the overall performance of juvenile specimens of C. huinayesis, measuring over three-months the coral growth, behaviour and respiration rates. The study consists of an ex-situ experiment which included three different treatments: i) the control treatment: with the current natural sediment concentration of Comau Fjord, ii) a 100-fold sediment concentration and iii) a 1000-fold sediment concentration than the control. The most remarkable result demonstrates that corals under the highest sediment concentrations display a significant decreased polyp activity (60 % lower) hence affecting pray capture thus nutrition, leading to a significant reduced growth rate (natural 0.14 ± 0.09 mg d-1; 100-fold: 0.09 ± 0.07 mg d-1; 1000-fold concentration: 0.003 ± 0.009 mg d-1). Furthermore, polyps partly retracted their tissue with increasing sediment load. The results show that all these effects seem to be lower for corals facing vertical downwards than for individuum’s growing horizontally. Another important result reveals that long-time exposed (13 weeks) juveniles significantly decrease their oxygen consumption which is directly related to increasing sediment load. Whereas newly exposed individuals (24 h) showed no significant change in their respiration rate under the influence of increased sedimentation load. The results of this experiment contribute to a better understanding of the abilities of CWC recruits to cope with anthropogenic impacts. This information is fundamental as the viability of the juveniles is indispensable for future coral populations and the so called ‘Cold-Water Stony Coral Forests‘. Consequently, management plans for the fjord need to consider the harmful effects of increased sedimentation on threatened CWC’s.

Description: Against the background of a drastically increased demand of marine proteins, off-bottom, bivalve aquaculture, provides significant potential for production growth when moved into more energetic marine waters. Hence, research, industry and politics are currently proposing the development of new offshore sites. The highly energetic conditions at these sites present a challenging environment for bivalve aquaculture. In this work, physical experiments of suspended bivalves provide new knowledge on the commonly used design parameters: the drag and inertia coefficients. Live bivalves and manufactured surrogate models at a 1:1 scale were tested in a towing tank as well as under waves. The drag coefficient of live blue mussels was determined to be Cd = 1.6 for Reynolds numbers between 2.3 × 104 and 1.4 × 105. The inertia coefficient obtained from the wave tests was Cm = 2.1 for Keulegan Carpenter numbers KC 〈 10. In a pursuit to better understand the differences between live mussels and surrogates in laboratory conditions, the analysis revealed that appropriate surrogates can be identified. A method to determine the characteristic diameter of mussel dropper lines is suggested. The results facilitate the future design of aquaculture systems in high-energy environments and allow for an integration into numerical models.

Description: Nowadays, high expectations are set for a digitally enabled circular economy (CE), to enhance resource efficiency. Tracing, tracking, and storing information is most important for this. In this paper, the application of Internet of Things (IoT) and Distributed Ledger Technology (Blockchain) are hence discussed by presenting the case of professional Electrical and Electronic Equipment (EEE) in Italy. Within the context of CE, prevention of electronic waste (WEEE) is extremely relevant as it is a fast-growing waste stream, and the products contain environmentally damaging substances as well as valuable and rare materials. The use of a proper combination of IoT and blockchain can help the producers to keep control on products until EEE end-of-life, while promoting CE strategies and supporting decision-making. Based on the outcomes of five interviews conducted in 2019 to companies of the EEE sector, potential improvements in the EEE end-of-use management are discussed. After providing the definition of requirements for both the technical solution and its testing are provided, three solution variations and the related business models are created and presented, as well as considerations on their environmental and economic impacts. The study shows how digital technologies can support the appropriate and circular management of EEE products and WEEE.