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The oleaginous alga Chlorella protothecoides accumulates lipid in its biomass when grown in nitrogen-restricted conditions. To assess the relationship between nitrogen provision and lipid accumulation and to determine the contribution of photosynthesis in mixotrophic growth, C. protothecoides was grown in mixo- and heterotrophic nitrogen-limited continuous flow cultures. Lipid content increased with decreasing C/N, while biomass yield on glucose was not affected. Continuous production of high lipid levels (57% of biomass) was possible at high C/N (87-94). However, the lipid production rate (2.48 g L(-1) d(-1)) was higher at D=0.84 d(-1) with C/N 37 than at D=0.44 d(-1) and C/N 87 even though the lipid content of the biomass was lower (38%). Photosynthesis contributed to biomass and lipid production in mixotrophic conditions, resulting in 13-38% reduction in CO2 production compared with heterotrophic cultures, demonstrating that photo- and heterotrophic growth occurred simultaneously in the same population.

It is recognised that several constraints such as the lack of knowledge and expertise of farmers, land users and policy makers concerning agroforestry systems establishment and management hamper the adoption of agroforestry systems (Camilli et al. 2017). AFINET project acts at EU level in order to direct research results into practice and promote innovative ideas to face challenges and solve practitioners' problems. AFINET proposes an innovative methodology based on the creation of a European Interregional Network, linking different Regional Agroforestry Innovation Networks (RAINs). RAINs represent different climatic, geographical, social and cultural conditions and enclose a balanced representation of the key actors with complementary types of expertise (farmers, policy makers, advisory services, extension services, etc.). The Italian RAIN is focused on the Extra-Virgin Olive Oil (EVOO) value chain, with the main aim to promote agroforestry management of local olive orchards. Olive trees are still managed traditionally, often in marginal sites, with minimal mechanization and relatively low external inputs such as chemical treatments in comparison to other crops. The presence of permanent crops (olive trees) guarantees a partially tree cover reducing hydrogeological risk. Soil management usually keeps natural grassing reducing soil carbon emission and increasing soil fertility (Bateni et al. 2017). Intercropping with cereals and/or fodder legumes and livestock can also be practiced in olive orchards, increasing the complexity of the olive tree multifunctional system. Moreover, olive orchards can be managed as agroforestry systems since they can be intercropped with arable crops (cereals, legumes) and/or combined with livestock (sheep, poultry). The RAIN process, involving local stakeholders, highlighted the main bottlenecks of the EVOO value chain related to communication and dissemination of knowledge, technical and management aspects, market and policy. In order to contrast bottlenecks and exploit opportunities of the olive oil supply chain, the identified innovations are: i) adoption of best practices: testing and experimenting innovative agroforestry systems introducing different crop/animals species and varieties; ii) improve the management of the olive orchards: encouraging and increasing the organic production; iii) valorisation of olive processing residues: identifying and testing innovative products (bio-materials, olive paste as example); iv) arise the awareness among consumers: educating people about the benefits of olive oil consumption, creating networks among stakeholders, improving marketing and commercialization. Creating a Bio-district, defined as a geographical area where farmers, citizens, tourist operators, associations and public authorities enter into an agreement for the sustainable management of local resources, emerged a powerful tool to implement the innovation in the local EVOO value chain.

Abstract The question whether coexistence of marine renewable energy (MRE) projects and marine protected areas (MPAs) is a common spatial policy in Europe and how a number of factors can affect it, has been addressed by empirical research undertaken in eleven European marine areas. Policy drivers and objectives that are assumed to affect coexistence, such as the fulfillment of conservation objectives and the prioritization of other competing marine uses, were scored by experts and predictions were crosschecked with state practice. While in most areas MRE-MPA coexistence is not prohibited by law, practice indicates resistance towards it. Furthermore expert judgment demonstrated that a number of additional factors, such as the lack of suitable space for MRE projects and the uncertainty about the extent of damage by MRE to the MPA, might influence the intentions of the two major parties involved (i.e. the MRE developer and the MPA authority) to pursue or avoid coexistence. Based on these findings, the interactions of these two players are further interpreted, their policy implications are discussed, while the need towards efficient, fair and acceptable MRE-MPA coexistence is highlighted.

Estuaries are among the most valuable aquatic systems by their services to human welfare. However, increasing human activities at the watershed along with the pressure of climate change are fostering the co-occurrence of multiple environmental drivers, and warn of potential negative impacts on estuaries resources. At present, no clear understanding of how coastal ecosystems will respond to the non-stationary effect of multiple drivers. Here we analysed the temporal interaction among multiple environmental drivers and their changing priority on shaping phytoplankton response in the Bahía Blanca Estuary, SW Atlantic Ocean. The interaction among environmental drivers and the number of significant direct and indirect effects on chlorophyll concentration increased over time in concurrence with enhanced anthropogenic stress, changing winter climate and wind patterns. Over the period 1978-1993, proximal variables such as nutrients, water temperature and salinity, showed a dominant effect on chlorophyll, whereas in more recent years (1993-2009) climate signals (SAM and ENSO) boosted indirect effects through its influence on precipitation, wind, water temperature and turbidity. Turbidity emerged as the dominant driver of chlorophyll while in recent years acted synergistically with the concentration of dissolved nitrogen. As a result, chlorophyll concentration showed a significant negative trend and a loss of seasonal peaks reflecting a pronounced reorganisation of the phytoplankton community. We stress the need to account for the changing priority of drivers to understand, and eventually forecast, biological responses under projected scenarios of global anthropogenic change.

Available methods for measuring the impact of ocean acidification (OA) and leakage from carbon capture and storage (CCS) on marine sedimentary pH profiles are unsuitable for replicated experimental setups. To overcome this issue, a novel optical sensor application is presented, using off-the-shelf optode technology (MOPP). The application is validated using microprofiling, during a CCS leakage experiment, where the impact and recovery from a high CO2 plume was investigated in two types of natural marine sediment. MOPP offered user-friendliness, speed of data acquisition, robustness to sediment type, and large sediment depth range. This ensemble of characteristics overcomes many of the challenges found with other pH measuring methods, in OA and CCS research. The impact varied greatly between sediment types, depending on baseline pH variability and sediment permeability. Sedimentary pH profile recovery was quick, with profiles close to control conditions 24 h after the cessation of the leak. However, variability of pH within the finer sediment was still apparent 4 days into the recovery phase. Habitat characteristics need therefore to be considered, to truly disentangle high CO2 perturbation impacts on benthic systems. Impacts on natural communities depend not only on the pH gradient caused by perturbation, but also on other processes that outlive the perturbation, adding complexity to recovery.

AbstractPlant species exert a dominant control over the nitrogen (N) cycle of natural and managed grasslands. Although in intensively managed systems that receive large external N inputs the emission of the potent greenhouse gas nitrous oxide (N2O) is a crucial component of this cycle, a mechanistic relationship between plant species and N2O emissions has not yet been established. Here we use a plant functional trait approach to study the relation between plant species strategies and N2O emissions from soils. Compared to species with conservative strategies, species with acquisitive strategies have higher N uptake when there is ample N in the soil, but also trigger N mineralization when soil N is limiting. Therefore, we hypothesized that (1) compared to conservative species, species with acquisitive traits reduce N2O emissions after a high N addition; and (2) species with conservative traits have lower N2O emissions than acquisitive plants if there is no high N addition. This was tested in a greenhouse experiment using monocultures of six grass species with differing above‐ and below‐ground traits, growing across a gradient of soil N availability. We found that acquisitive species reduced N2O emissions at all levels of N availability, produced higher biomass and showed larger N uptake. As such, acquisitive species had 87% lower N2O emissions per unit of N uptake than conservative species (p < .05). Structural equation modelling revealed that specific leaf area and root length density were key traits regulating the effects of plants on N2O emission and biomass productivity. These results provide the first framework to understand the mechanisms through which plants modulate N2O emissions, pointing the way to develop productive grasslands that contribute optimally to climate change mitigation.

In this work, a novel enhanced deep borehole heat exchanger (EDBHE) was proposed to improve heat extraction efficiency based on the jet grouting method. By means of this technology, a soilcrete zone with high thermal conductivity was built near the wellbore. To analyze the feasibility and efficiency of this method, we firstly constructed a validated deep borehole heat exchanger (DBHE) model based on the field experimental data. Numerical simulations were carried out to investigate the 30-year production performance of EDBHE. Results demonstrated that the jet grouting method is an efficient way for improving thermal output of DBHE. It is evaluated that the average annual heat production rate over a 30-year heating period of EDBHE is 463.2 kW, which is 1.27 times as that of DBHE. Sensitivity analyses indicate that the heat production rate and outlet temperature mainly depend on the height and radius of the artificial soilcrete zone. However, thermal output is not sensitive to thermal conductivity of the soilcrete zone due to the higher thermal resistance of the geological formation. For the experimental site used in this work, the recommended height, radius, and thermal conductivity of the soilcrete are 1000 m, 1.0 m, and 50 W/m °C, respectively.

This paper provides a synthesis and comparison of methodologies and results obtained in several studies devoted to the impact of climate change on hydropower. By putting into perspective various case studies, we provide a broader context and improved understanding of climate changes on energy production. We also underline the strengths and weaknesses of the approaches used as far as technical, physical and economical aspects are concerned. Although the catchments under investigation are located close to each other in geographic terms (Swiss and Italian Alps), they represent a wide variety of situations which may be affected by differing evolutions for instance in terms of annual runoff. In this study, we also differentiate between run-of-river, storage and pumping-storage power plants. By integrating and comparing various analyses carried out in the framework of the EU-FP7 ACQWA project, this paper discusses the complexity as well as current and future issues of hydropower management in the entire Alpine region.