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Vegetated coastal ecosystems, in particular mangroves, tidal marshes and seagrasses are highly efficient at sequestering and storing carbon, making them valuable assets for climate change mitigation and adaptation. The state of Queensland, in northeastern Australia, contains almost half of the total area of these blue carbon ecosystems in the country, yet there are few detailed regional or state-wide assessments of their total sedimentary organic carbon (SOC) stocks. We compiled existing SOC data and used boosted regression tree models to evaluate the influence of environmental variables in explaining the variability in SOC stocks, and to produce spatially explicit blue carbon estimates. The final models explained 75 % (for mangroves and tidal marshes) and 65 % (for seagrasses) of the variability in SOC stocks. Total SOC stocks in the state of Queensland were estimated at 569 ± 98 Tg C (173 ± 32 Tg C, 232 ± 50 Tg C, and 164 ± 16 Tg C from mangroves, tidal marshes and seagrasses, respectively). Regional predictions for each of Queensland's eleven Natural Resource Management regions revealed that 60 % of the state's SOC stocks occurred within three regions (Cape York, Torres Strait and Southern Gulf Natural Resource Management regions) due to a combination of high values of SOC stocks and large areas of coastal wetlands. Protected areas in Queensland play an important role in conserving SOC assets in Queensland's coastal wetlands. For example, ~19 Tg C within terrestrial protected areas, ~27 Tg C within marine protected areas and ~ 40 Tg C within areas of matters of State Environmental Significance. Using multi-decadal (1987-2020) mapped distributions of mangroves in Queensland; we found that mangrove area increased by approximately 30,000 ha from 1987 to 2020, which led to temporal fluctuations in mangrove plant and SOC stocks. We estimated that plant stocks decreased from ~45 Tg C in 1987 to ~34.2 Tg C in 2020, while SOC stocks remained relatively constant from ~107.9 Tg C in 1987 to 108.0 Tg C in 2020. Considering the level of current protection, emissions from mangrove deforestation are potentially very low; therefore, representing minor opportunities for mangrove blue carbon projects in the region. Our study provides much needed information on current trends in carbon stocks and their conservation in Queensland's coastal wetlands, while also contributing to guide future management actions, including blue carbon restoration projects.

Abstract Pyrolysis is currently being considered as an alternative method of treating sewage sludge. It yields residual oils and gases, which can be used as fuels, and a solid which can either be burned or physically activated with air or CO 2 . The aim of this work was to study the influence of different pyrolysis conditions (e.g. temperature and heating rate) on the reactivity in air and in CO 2 of carbonaceous materials obtained from these types of residues. An anaerobic sewage sludge produced in a Spanish urban waste water treatment plant, containing 5 wt.% moisture after air-drying, was pyrolyzed in an electrical laboratory furnace under different pyrolysis conditions. Non-isothermal reactivities (up to 1100°C) in air and in CO 2 of the carbonaceous materials obtained after pyrolysis were performed in a thermobalance. The TG and DTG curves obtained from these experiments are discussed.

Abstract The pyrolysis and combustion behaviour of a set of 11 Canadian coals with different ranks (lignite to low volatile bituminous) and maceral compositions has been investigated by TGA techniques. Temperature programmed heating of the coals was carried out both under nitrogen and under air, and the weight loss rates occurring in the two experimental conditions were compared in the whole temperature range studied (100–1000°C). Results showed that the pyrolysis curves of the coals do not match at all with any specific feature of the corresponding combustion profiles, and that the temperatures of initiation of both processes are very different in the low-rank end (higher initiation temperatures for pyrolysis), to become similar only for coal ranks of ∼0.8% vitrinite reflectance and above. This contradicts existing theories which state that coal combustion under TGA conditions is a three-stage process, namely volatiles release, vitrinite combustion and inertinite combustion. The processes leading to the weight loss rates occurring in the early stages of combustion were also investigated, with special emphasis in the temperature interval where no substantial weight losses had occurred yet in either a combustion or a pyrolysis experiment. This was done by heating the coals to 300°C in the TGA under air, and then switching the gas flow to nitrogen and allowing the sample to further devolatilise until 1000°C. Also, partly burnt and/or pyrolysed samples were obtained from the TGA and characterised by optical microscopy techniques. It was observed that the volatile yields of all the coals were substantially reduced as a consequence of their initial heating under air. Besides, evidences of melting and thermal annealing in the inner core of burning coal particles were noticed to occur at lower temperatures than in pyrolysing particles. This was attributed to a sealing effect of the oxidation rim formed in the early stages of combustion, which might give rise to a higher pressure build-up in the inner part of burning particles, thus enhancing the likelihood for condensation reactions to take place in the newly formed metaplast. As combustion profiles are commonly used to infer about combustion behaviour of coals, much care should be exercised in interpreting them, since even in a pure vitrain, two rather than one single material will be involved in the measured weight losses, and, more, these materials will often display fairly different reactivities.

Abstract Hollow silica microspheres have been synthesized with high surface area and homogenous porous size distribution to be evaluated for their CO2 adsorption capacity. All adsorbents were well fitted to the Henry model, except HMS-F that displays the highest CO2 adsorption capacity, which was adjusted to the Langmuir model. In order to increase the CO2 capture, the hollow silica microspheres were functionalized via grafting 3-aminopropyltriethoxysilane (APTES) and via impregnation with polyethyleniminethylenediamine branched (PEI) or tetraethylenepentamine (TEPA). In all cases, the adsorption isotherms of the amine functionalized silica are fitted to the Dual-Langmuir model, where physical and chemical adsorption sites are described. The isotherms reveal that grafted-silicas with APTES display the coexistence of both adsorption sites, while the adsorption process of impregnated-silicas with PEI or TEPA are governed by chemical interactions. The adsorption isotherms show that the most promising adsorbent for CO2 capture is HMS-F-TiPB, which reached a CO2 adsorption capacity of 3.4 mmol g−1 at 760 mmHg and 25 °C, maintaining this adsorption capacity 5 cycles.

AbstractTiming of breeding, an important driver of fitness in many populations, is widely studied in the context of global change, yet despite considerable efforts to identify environmental drivers of seabird nesting phenology, for most populations we lack evidence of strong drivers. Here we adopt an alternative approach, examining the degree to which different populations positively covary in their annual phenology to infer whether phenological responses to environmental drivers are likely to be (a) shared across species at a range of spatial scales, (b) shared across populations of a species or (c) idiosyncratic to populations.We combined 51 long‐term datasets on breeding phenology spanning 50 years from nine seabird species across 29 North Atlantic sites and examined the extent to which different populations share early versus late breeding seasons depending on a hierarchy of spatial scales comprising breeding site, small‐scale region, large‐scale region and the whole North Atlantic.In about a third of cases, we found laying dates of populations of different species sharing the same breeding site or small‐scale breeding region were positively correlated, which is consistent with the hypothesis that they share phenological responses to the same environmental conditions. In comparison, we found no evidence for positive phenological covariation among populations across species aggregated at larger spatial scales.In general, we found little evidence for positive phenological covariation between populations of a single species, and in many instances the inter‐year variation specific to a population was substantial, consistent with each population responding idiosyncratically to local environmental conditions. Black‐legged kittiwakeRissa tridactylawas the exception, with populations exhibiting positive covariation in laying dates that decayed with the distance between breeding sites, suggesting that populations may be responding to a similar driver.Our approach sheds light on the potential factors that may drive phenology in our study species, thus furthering our understanding of the scales at which different seabirds interact with interannual variation in their environment. We also identify additional systems and phenological questions to which our inferential approach could be applied.

Analyses of trimethylsilyl-derivatized neutral lipids by gas chromatography coupled to mass spectrometry afford a wealth of information contained in the marine sediments. This information is useful for unraveling the processes associated with past climate changes such as those from glacial and interglacial periods. Studies of samples from the Iberian Margin deposited about 1,300,000-1,400,000 years ago afforded the qualitative identification and quantification of n-alkanes, n-alkan-1-ols, isoprenoids, triterpenoids, sterols, hopanols, alkenones, alkenols, and polycyclic aromatic hydrocarbons. Using this information, the lipidomic approach has allowed to identifying differences in sea surface temperatures, marine productivity, microbial degradation processes, and inputs from continental plants between these periods. Differences in predominant higher plant species related to climate changes have also been observed.

Industrial expansion in the North Bohemian Coal District over the past decades has had an adverse effect not only on stream sediments but also on the freshwater system. So far mercury occurrence has not been properly investigated in the area. In response to this situation, the present study applies mercury quantification and speciation in order to predict the possible mobility of mercury. The enrichment factor (EF) and sediment quality guidelines (SQGs) were used to calculate the degree of mercury contamination. An automatic mercury analyser was employed to detect the total mercury content (Hg-T) and Thermal Desorption technique was used to identify mercury species. All the sediment samples were assessed with the contamination degree which increased to very severe in stream sediments in the middle section of the river course. Mercury species identified were chiefly the insoluble forms Hg-FeS2 and HgS. Lignite components and combustion residues were identified as the primary source of Hg contamination in the area.

Abstract This review deals with the state-of-the-art of waste tyre pyrolysis for the first time in literature. Pyrolysis has been addressed as an attractive thermochemical process to tackle the waste tyre disposal problem while allowing energy recovery. Pyrolysis enables the separation of carbon black from tyres and the volatile matter released (condensable and non-condensable compounds) has the potential of renewable energy recovery given the significant proportion of natural rubber present in the tyre. Given this waste-to-energy pathway, a comprehensive review has been carried out in order to show the effects of the main process conditions (heating rate, temperature, pressure, carrier gas flow rate and type, volatiles residence time and pyrolysis time) on the physicochemical properties and distributions of the resulting products (gas, liquid and solid fractions). It has also been reviewed the influence of the size and composition of the feedstock. All reported results have been framed regarding the type of reactor as well as the experimental conditions used to avoid contradictions among the large number of publications on the subject. It is shown that the occurrence of secondary reactions is very sensitive to the interaction of the aforementioned variables. Also, the main properties of the pyrolytic products are pointed out. The liquid and gaseous fractions obtained are a valuable fuel source; while the solid fraction (char) has the recovery potential of low- grade carbon black or as carbon adsorbent after applying an activation step. Special attention has been given to the liquid fraction, highlighting its properties as alternative fuel in compression ignition engines.