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Sinking marine aggregates have been studied for a long time to understand their role in carbon sequestration. Traditionally, sinking speed and respiration rates have been treated as independent variables, but two recent papers suggest that there is a connection albeit in contrasting directions. Here we collected recently formed (<2 days old) aggregates from sediment traps mounted underneath mesocosms during two different experiments. The mesocosms were moored off Gran Canaria, Spain (~ 27.9 N; 15.4 E) in a coastal, sub-tropical and oligotrophic ecosystem. We determined the respiration rates of organisms (mainly heterotrophic prokaryotes) attached to aggregates sinking at different velocities. The average respiration rate of fast sinking aggregates (>100 m d-1) was 0.12 d-1 ± 0.08 d-1 (SD). Slower sinking aggregates (<50 m d-1) had on average higher (p <0.001) and more variable respiration rates (average 0.31 d-1 ± 0.16 d-1, SD). There was evidence that slower sinking aggregates had higher porosity than fast sinking aggregates, and we hypothesize that higher porosity increase the settlement area for bacteria and the respiration rate. These findings provide insights into the efficiency of the biological carbon pump and help resolve the apparent discrepancy in the recent studies of the correlation between respiration and sinking speed. [ABSTRACT FROM AUTHOR]

This paper explores economic opportunities of Opuntia cultivation in Spain regarding fresh food production (comparing production structures of Mexico, Italy and Spain), cactus pear non-food uses (exploiting its bio-functional, medicinal, nutraceutical and cosmetic properties) and environmental issues related to climate change mitigation through soil carbon sequestration. Cactus pear production structures and costs are different in the three countries: Mexico (939.77 €), Italy (4.055.1 €) and Spain (9453.77 €). Spain does not present a real productive sector but only isolated farms. Opuntia is an interesting opportunity for non-food production due to the amount of its bioactive compounds. Main components (μg g−1 dried weight) are: kaempferol (34), myrcetin (65), isorhamnetin and derivatives (590), luteolin (8.4), ferulic acid and derivatives (1,050), and catechin (50). Obtaining these compounds could be a way of increasing cactus pear production profitability and creating jobs and value in rural areas. Cactus pear cultivation is a successful tool to mitigate climate change in arid and semiarid regions considering adequate farm and cultivation practices and systems. This crop is often located in high rurality areas, cultivated by small and micro-farmers. Cactus pear cultivation can be an effective tool for rural development in European arid and semiarid areas regarding production, job creation and environmental issues. • Opuntia is cultivated by micro-farmers in areas of high rurality. • Cactus pear cultivation could be a success to mitigate climate change in arid regions. • Opuntia can be an effective tool for rural development in European arid regions. • Italy presents a developed Opuntia sector and is the model to be followed. [ABSTRACT FROM AUTHOR]

Biomass equations have become a vital estimation tool and a prerequisite for studies on forest productivity, nutrient cycling and carbon sequestration. In this paper a new set of biomass equations were fitted for Eucalyptus globulus in Northern Spain. These equations allow us to estimate the total biomass and above- and below-ground fractions from the basal area and the height of the tree. A dummy variable was included in the model to calculate the root fraction of planted versus coppice stands. A descriptive study of the root system was also carried out to complete the information about this component. Root fraction plays an important role in forest structure, but is often omitted in carbon sequestration estimates due to the difficulties and cost associated with measurement. Our results indicated that root biomass accounted for 15% and 35% of total biomass in planted and coppice stands, respectively, at a shoot age equal to 9 years. We also found that the stand type and plantation age influenced the number of roots per root system, the volume of the root system and root length. This paper brings to light how coppice stands accumulate significant amounts of carbon in their root systems from the time a plantation is established. Such information makes it possible to orient ecosystem management towards potential for C fixation. [ABSTRACT FROM AUTHOR]

The rapid transformation of natural forest areas into fast-growing exotic species plantations, where the main objective is timber and pulp production, has led to a neglect of other services forests provide in many parts of the world. One example of such a problem is the county of Biscay, where the management of these plantations has negative impacts on the environment, creating the necessity to evaluate alternative tree species for use in forestry. The actual crisis in the forest sector of the region could be an opportunity to change to native species plantations that could help restore ecosystem structure and function. However, forest managers of the region are using the current interest on carbon sequestration by forest to persist with the “pine and eucalyptus culture”, arguing that these species provide a big C sequestration service. Moreover, they are promoting the expansion of eucalyptus plantations to obtain biomass for the pulp and paper industry and for bioenergy. The aim of this paper is to answer the following questions: Is this argument used by the foresters well-founded? or, could the use of native species in plantations improve the C sequestration service in Biscay while avoiding the environmental problems the actual plantations cause? To answer these questions we created three alternative future scenarios: a) the Services scenario, where there is a substitution of fast-growing exotic plantations by native broadleaf species plantations; b) the Biomass scenario, where there is a bet on eucalyptus plantations; and c) the Business as usual scenario. The changes in the C stock in living biomass in these scenarios have been simulated by a hybrid approach utilising inventories and models, and the period considered was 150 years. Our results show that the substitution of existing exotic plantations by plantations of native species has the greatest potential for increasing C sequestration. Although short- and mid-term outcomes may differ, when the long-term (more than 50 years) is considered, the C stock in the living biomass in the Services scenario is the greatest, accumulating 38% more C than the Business as usual scenario and 70% more C than the Biomass scenario at the end of the study period. Thus, changing pine and eucalyptus by native species in plantations, while solving some of the environmental problems of the actual plantations, sequesters more C in the long-term. As C sequestration initiatives only make sense if there is a good chance of long-term persistence of the C stocks created, there is no C sequestration argument for the foresters to continue with the actual policy of the use of fast-growing exotic species. [Copyright &y& Elsevier]

Agriculture and forestry activities are one of the many sources of greenhouse gas (GHG) emissions, but they are also sources of low-cost opportunities to mitigate these emissions compared to other economic sectors. This paper provides a first estimate of the potential for mitigation in the whole Spanish agriculture. A set of mitigation measures are selected for their cost-effectiveness and abatement potential and an efficient mix of these measures is identified with reference to a social cost of carbon of 40 €/tCO 2 e. This mix of measures includes adjusting crop fertilization and managing forests for carbon sequestration. Results indicate that by using the efficient mix of mitigation measures the annual abatement potential could reach 10 million tCO 2 e, which represents 28% of current agricultural emissions in Spain. This potential could further increase if the social cost of carbon rises covering the costs of applying manure to crops. Results indicate also that economic instruments such as input and emission taxes could be only ancillary measures to address mitigation in agriculture. These findings can be used to support the mitigation efforts in Spain and guide policymakers in the design of country-level mitigation strategies. [ABSTRACT FROM AUTHOR]

Livestock farming has been traditionally assessed by its economic figures, whereas the impact caused by their production models on the environment and on society have been largely disregarded. This paper analyses various organic cattle farming systems from the point of view of their technical-economic management, but also on the environmental impact caused by their greenhouse gas (GHG) emissions. Within this context, 34 organic meat cattle dehesa farms located in the southwest of Spain were studied. On the one hand, a principal component analysis devised four factors that explained the technical-economic management model of these farms in terms of their level of dependence on subsidies, production intensification, feeding practices and productivity. The farms were then divided into three clusters whose main differences came from the size of the farms, the intensification level and the joint rearing of cattle with other livestock species. On the other hand, GHG emissions and carbon sequestration levels for each of these clusters were calculated using the life cycle assessment methodology. The average GHG net emissions from the farms were 461.98 kg of CO 2 eq per ha (or 8.86 kg of CO 2 eq per kg of live weight of sold animal), with the largest and more extensive farms reporting 262.05 kg of CO 2 eq per ha (or 6.02 kg of CO 2 eq per kg of live weight of sold animal) and the smallest and more intensive farms resulting in as much as 697.49 kg of CO 2 eq per ha (or 11.18 kg of CO 2 eq per kg of live weight of sold animal). One of the most significant aspects of the study was the carbon sequestration capacity of dehesa extensive farms, which allowed these livestock systems to be in line with the preservation of the natural resources, animal welfare and the provision of ecosystem services. [Display omitted] • Sustainability of organic livestock farms is at risk due to low profitability. • C storage is a key ecosystem service of livestock systems to fight climate change. • Carbon sequestration in LCA reduces net emissions on extensive organic beef farms. • Livestock management on extensive organic farms improves climate change adaptation. [ABSTRACT FROM AUTHOR]

Abstract: Understanding soil dynamics is essential for making appropriate land management decisions, as soils can affect the carbon content from the atmosphere, emitting large quantities of CO2 or storing carbon. This property is essential for climate change mitigation strategies as agriculture and forestry soil management can affect the carbon cycle. The Mediterranean dehesa (Mediterranean grassland ecosystem with scattered oak trees — grazing system with Quercus ilex spp. ballota) is a silvopastoral system that integrates forestry, agricultural and livestock practices. The dehesa is characterized by the preservation of forest oaks that provide environmental services including carbon capture and storage. This paper shows the relationships between soil properties and soil organic carbon (SOC) in two soil types: Cambisols (CM) and Leptosols (LP), with two management systems: organic farming (OF) for 20years and conventional tillage (CT) in a Mediterranean dehesa of southern Spain without cropping. An analysis of 85 soil profiles was performed in 2009 in Los Pedroches Valley (Cordoba, southern Spain). The SOC stock (SOC-S) was greater in CM (75.64Mgha−1) than in LP (44.01Mgha−1). Physical parameters were the main variables affecting soil development. SOC-S was very similar in OF and CT (CM [74.90Mgha−1-CT; 76.39Mgha−1-OF] and LP [44.77Mgha−1-CT; 43.25Mgha−1-OF]). Data analysis showed that management practices had little effect on SOC storage in the study zone. Significant differences between soil types and management practices were found in SOC content for different horizons. The stratification ratio was >2 in both soils types (CM and LP) and management systems (OF and CT). These results indicate that the soil is of high quality, and that management practices have little influence on SOC-S in Los Pedroches Valley. [Copyright &y& Elsevier]

This paper reviews the devices suitable for building scale application and then outlines three case studies, two from Coventry, UK and one from Valencia, Spain. The first assesses the potential to retrofit an extensive green roof to the Frederick Lanchester Library, Coventry University. Costings are given, the structural strength of the building is investigated and various benefits of its installation, including potential to sequester and store carbon, are assessed. The second reports part of the AQUAVAL Project, Spain, whereby an extensive green roof was retrofitted to half of a school roof and porous concrete retrofitted to a pavement. Preliminary monitoring results show expected benefits, including attenuation of the storm peak and increased time to peak. The third case study using WinDes® software compared a conventionally drained new-build housing estate with a Sustainable Drainage Systems train of porous paving, bioretention and swales. Stormwater volume was reduced by ~20% and peak flow by >250 L s-1. Addition of extensive green roofs to all buildings increased these differences and delayed return to baseflow conditions reflecting water stored in the management train components. [ABSTRACT FROM AUTHOR]

Energy projections made by the World Energy Council, the International Energy Agency (IEA) and the US Energy Information Administration give similar pictures of the dominant role of fossil fuel in the future primary energy global demand and the necessity of incorporating CCS Technologies as part of the portfolio of solutions to reach the target world emission reduction in the coming years. Without CCS, CO2 emission levels by 2050 are expected to increase by 70%. One of the most relevant initiatives for the deployment of CCS technologies is promoted by the Spanish Government through the institution Fundacion Ciudad de la Energia (CIUDEN). CIUDEN is developing a complete programme focusing on the development of CCT and CCS technologies in Europe. CIUDEN's CO2 capture programme includes the construction and operation of a Technology Development Plant (TDP) in NW Spain (El Bierzo). The construction of the installation started in November 2008 and incorporates the following technologies: fuel preparation system, pulverised coal boiler (20 MWth), circulating fluidized bed boiler (30 MWth), biomass gasifier (3 MWth), flue gas cleaning train for NOx, dust and SOx and CO2 processing unit. This paper describes CIUDEN's TDP for CO2 capture, focusing on the particularities of the installation and design, and especially on the PC unit and equipment required for its operation. The experimental programme currently under way is also described. Results are expected to be an extraordinary advance in the development and strengthening of CCT and CCS technologies, particularly oxycombustion. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, different electricity demand scenarios for Spain are presented. Population, income per capita, energy intensity and the contribution of electricity to the total energy demand have been taken into account in the calculations. Technological role of different generation technologies, i.e. coal, nuclear, renewable, combined cycle (CC), combined heat and power (CHP) and carbon capture and storage (CCS), are examined in the form of scenarios up to 2050. Nine future scenarios corresponding to three electrical demands and three options for new capacity: minimum cost of electricity, minimum CO2 emissions and a criterion with a compromise between CO2 and cost (CO2-cost criterion) have been proposed. Calculations show reduction in CO2 emissions from 2020 to 2030, reaching a maximum CO2 emission reduction of 90% in 2050 in an efficiency scenario with CCS and renewables. The contribution of CCS from 2030 is important with percentage values of electricity production around 22–28% in 2050. The cost of electricity (COE) increases up to 25% in 2030, and then this value remains approximately constant or decreases slightly. [Copyright &y& Elsevier]

Lower Jurassic sedimentary successions in the Atlantic margin basins include several organic-rich intervals, some with source rock potential; time-equivalent units are also identified in on- and offshore areas worldwide. Despite decades of research, it is still unclear which mechanisms lead to the deposition of organic-rich sediments during the Early Jurassic. The objectives of this study are to construct a detailed temporal and geographical framework of Sinemurian–Toarcian organic matter preservation intervals (OMPIs; subdivided into local, regional, and superregional) and roughly constrain the relationship of OMPIs with the Lower Jurassic δ13C record. This survey combines an in-depth analysis of literature on the distribution of organic-rich facies in the Sinemurian–Toarcian with new geochemical studies [total organic carbon (TOC) and organic matter pyrolysis] from selected outcrop sections from Portugal, Spain, and Morocco. Strong local control on OMPIs during most of the Sinemurian is suggested. Regionally widespread organic-rich facies are associated with the most negative δ13C values of the broad Sinemurian–Pliensbachian negative carbon isotopic trend recorded in organic matter (including the Sinemurian–Pliensbachian Boundary Event). Pliensbachian OMPIs are expressive in the areas bordering the proto-Atlantic Ocean and are often linked with positive δ13C excursions and short-lived warm intervals, but OMPIs are also defined for the Late Pliensbachian cool interval. Early Toarcian superregional OMPIs are associated with some of the most pronounced δ13C excursions of the Mesozoic. Toarcian maximum TOC content occurs with the positive δ13C (recovery) trend following the δ13C negative shift typically linked with the Early Toarcian Oceanic Anoxic Event (T-OAE), supporting the notion that peak carbon sequestration/ocean anoxia post-dated the main phase of carbon input into the atmosphere, as also suggested by recent modelling efforts. However, additional superregional OMPIs predate and postdate the T-OAE, indicating that conditions favouring preservation of organic matter (increased productivity and/or enhanced preservation) during the Early Toarcian were not restricted to the T-OAE interval. The compilation of Sinemurian–Toarcian OMPIs presented in this paper demonstrates that organic-rich intervals of regional and superregional expression in the Lower Jurassic sedimentary record are ubiquitous and may even be more numerous than in the Cretaceous. Considering the association of some of the Sinemurian, Pliensbachian, and Toarcian (not taking into account the T-OAE related OMPIs) regional and superregional OMPIs with well-defined carbon isotopic excursions, it is here suggested that these hold the same relevance as the secondary OAEs of the Cretaceous, such as the Valanginian OAE (Weissert Event), Hauterivian OAE (Faraoni Event), and Late Aptian–Early Albian OAE (OAE 1b cluster). [ABSTRACT FROM AUTHOR]

• Almuñecar cherimoya are enriched in K, P, C and N. • Cherimoya seed suffered the least changes under unfavourable climatic conditions. • Cherimoya peel, enriched in Ca and Mg, could be used as amendment in acidic soils. • Addition of pruning wastes did not significantly change the nutrient concentration. Cherimoya, a tropical fruit from South America whose commercial demand is increasing for both its exceptional flavor and high nutritional content, is expanding in cultivation to subtropical areas such as the Mediterranean coast of Andalusia (Spain). In this paper, we analyze cherimoyas (peel, pulp, and seed) grown in Almuñécar (Granada, Spain) during the years 2013, 2015, and 2016 from trees applied with different pruning wastes (avocado, cherimoya, mango, and garden). The cherimoya fruits had high contents in most of the macronutrients, especially K, Ca, and micronutrients such as Fe and Zn. The Na, P, K and Ca concentrations were related to the plant mulch that released nutrients to the soil and led to a variation in soil-nutrient bioavailability by decreasing the soil pH. The seed was the part of the cherimoya that registered the least nutritional change due to annual weather differences and the highest positive effects of mulching in terms of increased nutrient availability after mulching. [ABSTRACT FROM AUTHOR]

Simple Summary: This paper attempts to analyze the impact of organic livestock farming in dehesas through the analysis and review of the carbon footprint of seven extensive organic farming systems in various dehesas in the southwest of Spain. The method used was life cycle assessment, taking into account both greenhouse emissions and carbon sequestration. Greenhouse emissions estimated are those derived from livestock digestion, manure management, soil management, and off-farm inputs (feeding, fuels, and electricity). Carbon sequestration calculations consider carbon fixation due to pasture and crop waste and carbon fixation in soil due to manure fertilization. The farms under study represent all the species bred in the farms and all the habitual farming systems existing in dehesas, with the following types being under analysis: beef cattle, sheep for meat, Iberian pigs, and dairy goats. The emissions identified in the farms under study have been found to be lower than those from conventional farms, with values of 16.27 and 10.43 kg CO2eq/kg of live weight for beef cattle, 13.24 and 11.42 kg CO2eq/kg of live weight for sheep, 1.19 kg CO2eq/kg of milk for goats, and 4.16 and 2.94 kg CO2eq/kg of live weight for pigs. The levels of carbon sequestration are also noticeably higher, with compensation being up to 89% in meat producing ruminants' farms, 100% in dairy goats' farms, and values compensating the total emissions in the case of Iberian montanera pig farms. This study employs life cycle assessment (LCA) for the calculation of the balance (emissions minus sequestration) of greenhouse gas emissions (GHG) in the organic livestock production systems of dehesas in the southwest region of Spain. European organic production standards regulate these systems. As well as calculating the system's emissions, this method also takes into account the soil carbon sequestration values. In this sense, the study of carbon sequestration in organic systems is of great interest from a legislation viewpoint. The results reveal that the farms producing meat cattle with calves sold at weaning age provide the highest levels of carbon footprint (16.27 kg of carbon dioxide equivalent (CO2eq)/kg of live weight), whereas the farms with the lowest levels of carbon emissions are montanera pig and semi-extensive dairy goat farms, i.e., 4.16 and 2.94 kg CO2eq/kg of live weight and 1.19 CO2eq/kg of fat and protein corrected milk (FPCM), respectively. Enteric fermentation represents 42.8% and 79.9% of the total emissions of ruminants' farms. However, in pig farms, the highest percentage of the emissions derives from manure management (36.5%–42.9%) and animal feed (31%–37.7%). The soil sequestration level has been seen to range between 419.7 and 576.4 kg CO2eq/ha/year, which represents a considerable compensation of carbon emissions. It should be noted that these systems cannot be compared with other more intensive systems in terms of product units and therefore, the carbon footprint values of dehesa organic systems must always be associated to the territory. [ABSTRACT FROM AUTHOR]