Fossil Counterparts Research Articles

Spore morphology of Adiantum species from the Indian subcontinent using LM and FESEM: palaeoecological analysis and phylogenetic delineation

The palynology of fern spores has proven to be an immensely useful tool in the identification and phylogenetic characterization of various fern taxa. A diverse range of spore morphologies have been studied; nevertheless, the present investigation of 21 species of Adiantum under light microscopy (LM) and field emission scanning electron microscopy (FESEM) is a maiden attempt from India to develop a spore micro-morphometric dataset that reflects taxonomic traits, fossil counterparts, and evolutionary changes. The studied spores of Adiantum species possess significant differences in lete character (aperture, primary character), exospore ornamentation (secondary character), and spore shape (tertiary character). The sexine pattern varies from psilate to verrucate, scabrate to granulate, and rugulate to fossulate (eurypalynous type). The perine is a characteristic feature of fern spores, as evident in A. myriosorum, A. zollingeri and A. philippense, suggesting the diversity among different Adiantum spores. The multivariate statistical analysis indicates three major clusters based on spore morphological characteristics. The evolutionary outcome of this micro-morphometric analysis showed that the spore of A. formosum includes the most primitive characters (such as unconstricted lete arm, smooth exospore, and non-perinate sclerine), whereas the spores of A. zollingeri and A. myriosorum possess advanced characters (such as constricted lete arms, rugulate exospores, and perinate sclerine). This extensive spore morphological examination will provide a comprehensive dataset for the identification of fossil spores (to the species level) and for the taxonomic characterization of Adiantum species in India and comparison of them with other species around the world.

Comparative analysis of the combustion and emission characteristics of biojet and conventional Jet A‐1 fuel: a review

AbstractConventional jet fuels derived from fossil sources contribute to greenhouse gas emissions and air pollution, leading to climate change. Recent studies have shown that biobased jet fuels from different feedstocks offer a more sustainable alternative to conventional fuels as they are derived from renewable biomass, reducing greenhouse gas emissions. The major feedstocks reviewed are jatropha curcas, camelina, karanja oil, waste cooking oil, and municipal solid waste. They offer diverse benefits for sustainable aviation fuel development. As a comparative analysis, this review examined jet fuel characteristics based on their physicochemical properties, namely energy content, viscosity, calorific value, cetane number, and freezing and flash points. The objective was to understand the influence of the properties on performance evaluation, environmental impact, and combustion characteristics. The properties of biojet fuels are compared with their fossil counterparts to validate their suitability as renewable alternatives and their benefits in terms of emissions reduction and engine performance. Biojet fuels perform better in terms of lower sulfur content, lower soot content, and a lower freezing point, their aromatic content, and their high cetane number. This study enhances the understanding of biojet fuels and their quality, and supports the development of sustainable fuel options. Overall, adherence to the American Society for Testing and Materials (ASTM) D7566‐18 standard is crucial for the acceptance and integration of biojet fuels into the aviation sector. Future research should explore feedstocks such as wood biomass, wastepaper, and agricultural residues for biojet fuels. It should also investigate the combustion and emission characteristics of biosourced aviation fuel at higher blending ratios (>50% by volume) with fossil Jet A‐1.

Integrating aerosol emissions of forest biomass into a life cycle assessment of forest-based production

Climate change mitigation is globally increasing the demand for forest biomass to substitute for fossil-based materials. Consequently, fossil-based greenhouse gas emissions will decrease, but simultaneously, aerosol emissions may substantially change. The evaluation of the substitution effects of forest-based materials may be biased if aerosol emissions are not considered. We integrated aerosol emissions from the use of forest-based biomass and fossil-based materials into a life cycle assessment (LCA) tool and simulated the biomass production of Norway spruce under alternative harvest intensities of energy biomass in middle boreal conditions in Finland. For the forest management regimes, we calculated particulate matter (PM) emissions; i.e. total suspended particles (TSP), respirable particulate matter (PM10), fine particulate matter (PM2.5) and black carbon (BC), and gaseous emissions including nitrogen oxides (NOx), sulphur dioxide (SO2) and non-methane volatile organic compounds (NMVOC). We also considered how replacing fossil counterparts and peat with forest-based biomass energy affects aerosol emissions. The differences between the management regimes were minor for sawn logs and pulpwood. Energy biomass use, especially combustion in small-scale appliances, increased aerosol emissions. Energy biomass use produced higher PM (TSP, PM10, PM2.5, BC) emissions than the use of coal and peat as energy. Regarding construction materials, the highest aerosol emissions were found for sawn wood production, followed by steel production. Cardboard production emitted remarkably higher aerosol emissions than high-density polyethylene (HDPE) plastic production. The inclusion of aerosol emissions of forest biomass use seems to be important for assessing the climate and health effects of the transition to a forest bioeconomy.

Modelling assessment of resource competition for renewable basic chemicals and the effect of recycling

AbstractThis work assesses pathways towards a net‐zero greenhouse gas (GHG) emissions chemical industry sector in Germany until 2050, focusing on the ammonia, methanol, ethylene and adipic acid subsectors and the effect of the recycling of C embedded in chemical end products on the GHG abatement cost and primary resource demand. This was done using a bottom‐up mathematical optimization model, including the energy sectors and the chemicals sector, with electricity and biobased options considered. Results show that net‐zero GHG emissions for the considered chemicals in 2050 are attainable at a marginal cost of 640–900 €/tCO2‐eq, even with 26%–36% of demand being satisfied by fossil production routes. This is possible because renewable organic chemicals can act as carbon sinks if, at their end of life, C is permanently stored via landfilling or passed on to the next value chain via recycling. Nonetheless, considering the cost implications, the practical deployment of renewable chemicals is a challenge. The considered renewable chemicals cost 1.3–8 times more than their fossil counterparts, resulting in a marginal CO2 price of 480 €/tCO2‐eq when all primary resources (energy crops, forest residues and renewable electricity) are considered, or 810 €/tCO2‐eq when the availability of arable land is restricted. In the transition to net‐zero emissions for the chemicals under study, a circular economy is important not only for reducing demand for primary resources as is typically the case but also reduces GHG abatement costs by 13%–24% through carbon capture and utilization effects.

MISS from a temperate hypersaline saltpan under continental influence (Salitral de La Vidriera, Argentina)

The Salitral de La Vidriera (SDV; 38°44′S, 62°34′W) once occupied the innermost section of a funnel-shaped estuary before its isolation due to sea level drop ∼3000 years BP. It currently is a continental saltpan detached from the Bahía Blanca estuary, having no marine connection, and acting as a hypersaline evaporitic environment. This study provides a first-hand characterization of the epibenthic microbial mats that biostabilize surface sediments in the saltpan, and the environmental dynamics and physical deformation agents behind the formation of modern Microbially Induced Sedimentary Structures (MISS). The microbial community in the hypersaline mats is dominated by cyanobacteria of filamentous (taxonomic order Oscillatoriales) and coccoid morphologies (orders Chroococcidiopsidales and Pleurocapsales). The MISS comprise rolled-up mats, flipped-over mats, folds and wrinkles, reticulate surfaces, gas domes, pinnacles, and desiccation cracks; their genesis is linked to the presence of water that either promotes microbial growth or creates hydrodynamic deformation structures. Gypsum crystals were found in surface and subsurface sediments plausibly linked to a high rate of rainwater evaporation and aided in their preservation by the microbial mat lattice. Furthermore, carbonate precipitation in the form of peloids was identified through petrographic analysis, despite the siliciclastic nature of sediments. The occurrence of modern MISS in this transitional environment, currently under continental influence, is discussed and contrasted with modern peritidal environments. Descriptions from this study, contextualized in a modern depositional setting, may be useful in the study of fossil counterparts and paleoenvironmental reconstructions.

The potential of emerging bio-based products to reduce environmental impacts

The current debate on the sustainability of bio-based products questions the environmental benefits of replacing fossil- by bio-resources. Here, we analyze the environmental trade-offs of 98 emerging bio-based materials compared to their fossil counterparts, reported in 130 studies. Although greenhouse gas life cycle emissions for emerging bio-based products are on average 45% lower (−52 to −37%; 95% confidence interval), we found a large variation between individual bio-based products with none of them reaching net-zero emissions. Grouped in product categories, reductions in greenhouse gas emissions ranged from 19% (−52 to 35%) for bioadhesives to 73% (−84 to −54%) for biorefinery products. In terms of other environmental impacts, we found evidence for an increase in eutrophication (369%; 163 to 737%), indicating that environmental trade-offs should not be overlooked. Our findings imply that the environmental sustainability of bio-based products should be evaluated on an individual product basis and that more radical product developments are required to reach climate-neutral targets.

Parrotia (Hamamelidaceae) pollen morphology and a glimpse into the fossil record and historical biogeography

The affiliation of fossil pollen grains of Hamamelidaceae with extant genera is still a challenge for palynologists, probably due to the scarcity of pollen morphological documentation and comparison of Hamamelidaceae genera and species and their fossil counterparts. Parrotia once had a much wider geographical range during geological time according to fossil records, including macrofossils (e.g., plant leaves, and flowers) and microfossils (e.g., pollen). However, assigning fossil pollen of Parrotia is yet difficult regardless of some previous work available on pollen morphology.In this study, we present new results after intensive re-examination on the pollen morphology of Parrotia using light microscope (LM) and scanning electron microscope (SEM), aiming to assess pollen diagnostic features as a guide for fossil pollen recognition. We also compared the reticulum sculptures and nanoscale ornamentations on the muri around lumina for six genera in the tribes Fothergilleae with the representative genera from the neighboring tribes Hamamelideae and Eustigmatea. Hamamelidaceae fossil pollen types from Miocene sediments in southeastern China were examined and identified. We found that 1) pollen grains of Parrotia persica and P. subaequalis have significantly different dimensions of the length of lumen and density of lumina (numbers/10 μm2) under SEM, and the lengths of polar axis, equatorial axis, colpus, bottom side of polar view and height of polar view under LM, respectively; 2) the peculiarities of reticulum, microechinae on the muri and arrangement pattern under SEM are useful diagnostic features to differentiate pollen types of Fothergilleae groups down to genus level from two neighboring tribes; 3) two sister species of Parrotia show identifiable characteristics of reticulum and microechinae based on high resolution imaging with SEM, however, it should be noted that assigning fossil pollen to Fothergilleae still need caution, because of some similar looking close genera under LM; 4) inter- and intraspecific pollen variations need to be carefully considered, when identifying dispersed or fossil pollen grains of Parrotia under low resolution of LM imaging; 5) nanoscale structures based on high resolution imaging for pollen surface sculptures are important keys to distinguishing different fossil pollen types of Hamamelidaceae, including Parrotia.Most of fossil sites of Parrotia are concentrated in Europe-Eurasia and Japan in East Asia, but there are relatively fewer in China and America. To have an insight into the historical biogeography of Parrotia, the global fossil records of Parrotia were comprehensively reviewed and visualized in three large regions (northern American, Europe-Eurasia and East Asia). The palaeophytogeography of Parrotia in light of fossil pollen in East Asia is also generally discussed. Further investigations of the fossil record of Parrotia are expected prior to fully picturing its past phytogeography and species diversity through time, particularly some missing links during Pliocene and Quaternary in China.

Geometric morphometrics and paleoproteomics enlighten the paleodiversity of Pongo

PleistocenePongoteeth show substantial variation in size and morphology, fueling taxonomic debates about the paleodiversity of the genus. We investigated prominent features of the enamel-dentine-junction junction (EDJ)–phylogenetically informative internal structures–of 71 fossilPongolower molars from various sites by applying geometric morphometrics and conducted paleoproteomic analyses from enamel proteins to attempt to identify extinct orangutan species. Forty-three orangutan lower molars representingPongo pygmaeusandPongo abeliiwere included for comparison. The shape of the EDJ was analyzed by placing five landmarks on the tip of the main dentine horns, and 142 semilandmarks along the marginal ridges connecting the dentine horns. Paleoproteomic analyses were conducted on 15 teeth of Late PleistocenePongousing high-resolution tandem mass spectrometry. The geometric morphometric results show variations in EDJ shape regarding aspects of the height and position of the dentine horns and connecting ridges. Despite the issue of molar position and sample size, modern molars are distinguished from fossil counterparts by their elongated tooth outline and narrowly positioned dentine horns. Proteomic results show that neither a distinction ofP.pygmaeusandP.abelii, nor a consistent allocation of fossil specimens to extant species is feasible. Based on the EDJ shape, the (late) Middle to Late PleistocenePongosamples from Vietnam share the same morphospace, supporting the previous allocation toP.devosi, although substantial overlap with Chinese fossils could also indicate close affinities withP.weidenreichi. The hypothesis that both species represent one chronospecies cannot be ruled out. Two fossil specimens, one from Tam Hay Marklot (Laos, Late Pleistocene), and another from Sangiran (Java, Early to Middle Pleistocene), along with some specimens within the Punung sample (Java), exhibit affinities withPongo abelii. The Punung fossils might represent a mix of early Late Pleistocene and later specimens (terminal Pleistocene to Holocene) related to modernPongo. The taxonomy and phylogeny of the complete Punung sample needs to be further investigated.

Absolute Sustainability Assessment of Flue Gas Valorization to Ammonia and Synthetic Natural Gas.

Carbon capture and utilization has gained attention to potentially curb CO2 emissions while generating valuable chemicals. These technologies will coexist with fossil analogs, creating synergies to leverage circular economy principles. In this context, flue gas valorization from power plants can assist in the transition. Here, we assessed the absolute sustainability of a simulated integrated facility producing ammonia and synthetic natural gas from flue gas from a combined-cycle natural gas power plant based in Germany, using hydrogen from three water electrolysis technologies (proton exchange membrane, alkaline, and solid oxide cells), nitrogen, and CO2. For the first time, we applied the planetary boundaries (PBs) framework to a circular integrated system, evaluating its performance relative to the safe operating space. The PB-LCA assessment showed that the alternative technologies could significantly reduce, among others, the impact on climate change and biosphere integrity when compared to their fossil counterparts, which could be deemed unsustainable in climate change. Nevertheless, these alternative technologies could also lead to burden shifting and are not yet economically viable. Overall, the investigated process could smoothen the transition toward low-carbon technologies, but its potential collateral damages should be carefully considered. Furthermore, the application of the PBs provides an appealing framework to quantify the absolute sustainability level of integrated circular systems.

Porcelaneous larger foraminiferal responses to Oligocene–Miocene global changes

Sea surface temperatures (SST) have been identified as a main controlling factor on larger benthic foraminifera (LBF) living in tropical to sub-tropical shallow-water carbonate and mixed siliciclastic‑carbonate platforms. Changes in SST, along with those in ocean acidification and nutrient content recorded in the global oceans throughout their history will not only continue but also be amplified in the future at an unprecedented rate of change possibly reaching levels found in the geological record. This study focuses on the Oligocene (mean SST 8 °C higher than present) and the Miocene (SST 5–8 °C higher than present) epochs which were characterized by a higher richness in porcelaneous LBF (pLBF) than today. A systematic re-assessment and comprehensive literature survey of stratigraphic ranges and palaeogeographic distribution in the Western Tethyan (Mediterranean) and Indo-Pacific regions are used to evaluate the impact of changes in SST, seawater pCO2 and pH on the biodiversity of the Oligocene–Miocene pLBF Alveolinella, Austrotrillina, Borelis, Bullalveolina, Flosculinella, and Praebullalveolina. Two peaks in species richness were identified during the Aquitanian and Langhian–Serravallian. These peaks occurred when SST was ∼29 °C, with pCO2 of ∼400 ppm and pH > 7.8. These values are comparable to those of today. The minima in species richness recorded in the Rupelian–early Chattian, in the Burdigalian and from the Tortonian onward can be correlated to the detrimental effects of both minimum (< 26 °C) and maximum (> 31 °C) SST thresholds. High pCO2 (> 600 ppm) values, which are limited to the Rupelian–early Chattian, are also detrimental to species richness. Seawater pH higher than 7.7 did not negatively affect species richness. These historical trends have serious implications for the future diversity of pLBFs with the increasing likely scenario of rising SST and pCO2 and lowering of pH values in the near future. These developments can potentially lead to diversity decrease and even extinction of pLBFs. However, the resilience of present-day pLBF species to rising SST and pCO2 levels is underpinned by the evolutionary histories of their fossil counterparts during climate variations, albeit at much different rates of change.

Integrating ex-ante and prospective life-cycle assessment for advancing the environmental impact analysis of emerging bio-based technologies

Unlike the fossil-based alternatives, many emerging bio-based technologies are still at the early lab or pilot scale and are not representative of optimized industrial conditions. This makes a robust comparison of their environmental performances via life-cycle assessment (LCA) challenging. We propose a framework to combine scaling-up projections of early-stage technologies (ex-ante LCA) with the influence of future socio-economic scenarios (prospective LCA), using a range of new bio-based polymers produced from forest residues as case study. The combined framework takes a step-by-step approach in modifying process inventories and projecting them to a future industrial scale for the environmental impact assessment. In our case study, the climate change impact from lab-scale processes decreases from 105–471 kg CO2-eq./kg of polymer to 9–14 kg CO2-eq./kg after the application of ex-ante LCA, with the highest reduction (83 %) coming from identified process synergies (e.g., solvent recovering). Combining the ex-ante and prospective LCA additionally reduces the impact up to 56 % by 2050, relative to ex-ante LCA results only. Other environmental impacts decrease as well, particularly freshwater eutrophication (up to 99 % reduction), photochemical oxidant formation (99 %), and marine eutrophication (98 %). The framework secures a more robust comparison of emerging bio-based products with conventional fossil-based alternatives, and as such it helps the identification of the improvements in both the bio-based technological processes and background supply chains that are needed to make bio-based systems outperform their fossil counterparts. A consistent integration of ex-ante and prospective LCA is instrumental to prioritize research and investments for upscaling the early-stage technologies that are most promising from a sustainability perspective, and ultimately guide a sustainable transition towards a circular bioeconomy.

Conceptual process design and technoeconomic analysis of an e-ammonia plant: Green H2 and cryogenic air separation coupled with Haber-Bosch process

Manufacturing low-carbon ammonia (NH3) is paramount for the green transition of the chemical industry and society at large. The conventional Haber-Bosch (HB) process based on steam methane reforming (SMR) entails whopping CO2 emissions (i.e., 400 Mt y−1), therefore we propose a sustainable plant design comprising water electrolysis and cryogenic distillation for H2 and N2 production, respectively. This electrified configuration powered by wind energy affords 80% lower carbon emissions than the conventional SMR-based process. However, the electrolyser unit can represent between 36 and 61% of the total capital cost, depending on its energy efficiency, and its high energy demand drives the electricity cost which accounts for more than 68% of the plant operational costs. Thus, even with anticipated improvements in efficiency of the electrolyser unit, the Levelized Cost of Production (LCOP) of e-NH3 in a 2050 scenario is 65% higher than the current benchmark; nonetheless, the two processes could be equally viable with a 135.8 $ tCO2−1 carbon penalty on the average conventional process. Notably, the cost of electricity is the most prominent cost driver in the e-process, which could be more economically viable than the fossil counterpart with electricity prices below 12.5 $ MWh−1. These findings provide evidence that the proposed e-process can replace the commercial benchmark in small-scale, standalone applications.

Holistic Approach to Process Design and Scale-Up for Itaconic Acid Production from Crude Substrates

Bio-based bulk chemicals such as carboxylic acids continue to struggle to compete with their fossil counterparts on an economic basis. One possibility to improve the economic feasibility is the use of crude substrates in biorefineries. However, impurities in these substrates pose challenges in fermentation and purification, requiring interdisciplinary research. This work demonstrates a holistic approach to biorefinery process development, using itaconic acid production on thick juice based on sugar beets with Ustilago sp. as an example. A conceptual process design with data from artificially prepared solutions and literature data from fermentation on glucose guides the simultaneous development of the upstream and downstream processes up to a 100 L scale. Techno-economic analysis reveals substrate consumption as the main constituent of production costs and therefore, the product yield is the driver of process economics. Aligning pH-adjusting agents in the fermentation and the downstream process is a central lever for product recovery. Experiments show that fermentation can be transferred from glucose to thick juice by changing the feeding profile. In downstream processing, an additional decolorization step is necessary to remove impurities accompanying the crude substrate. Moreover, we observe an increased use of pH-adjusting agents compared to process simulations.

Is sugarcane-based polyethylene a good alternative to fight climate change?

The need to decarbonize and reduce the impact of human activities is opening the window for new bioproducts. The industry of bioplastics has grown exponentially in the past years, and its production is expected to triple by 2026. Different bioplastics are currently produced, but bio-polyethylene constitute an interesting opportunity since its fossil counterpart is one of the most used materials worldwide, and its precursor, ethylene, is one of the highest contributors to GHG emissions in the chemical industry. The true environmental impact of this bio-based plastic remains under controversial discussions due to a wide distribution of environmental indicators values found in the literature for this material. We aim to thoroughly evaluate the environmental impact of bio-polyethylene made from sugarcane across the different production stages through a life cycle analysis. Our goal is also to assess unintended consequences (consequential effects) of producing it. It was determined that land-use change represents the main aspect affecting the environmental sustainability of bio-polyethylene. From an attributional point of view, this bioplastic could present lower carbon footprints than fossil polyethylene if no deforestation occurs. From a consequential standpoint, indirect deforestation as a response to producing more bioplastic could negatively impact the environmental profile of this material. Policies restricting deforestation are required to ensure that bio-polyethylene can constitute an alternative to reduce the carbon footprint of products in both scenarios. We expect this work to provide a robust evaluation to understand the environmental impact of bio-polyethylene, which will help the industry understand the place of this bio-based plastic and increase the offering of more sustainable products.

Energy crisis in Europe enhances the sustainability of green chemicals.

Ammonia and methanol are essential to modern societies, but their production has been heavily reliant on natural gas, which contributes to supply disruptions and significant CO2 emissions. While low-carbon or green production routes have been extensively researched, their adoption has been hindered by higher costs, making them unsustainable. However, a recent energy crisis in Europe has created a unique opportunity to shift towards greener production technologies. Here we show that, green ammonia, produced through wind-powered water electrolysis, had the potential to outperform its fossil counterpart for six months as of December 2021, while methanol produced through CO2 capture and wind-based water electrolysis became an economically appealing alternative. With a coordinated effort from academia, industry, and policymakers, Europe can lead the grand transition towards more sustainable practices in the chemical industry.

Mind the Pulp: Environmental and economic assessment of a sugar beet pulp biorefinery for biobased chemical production

Sugar beet pulp, a byproduct from sugar beet refining, is used by farmers as fertilizer or sold as animal feed. Both options underestimate the potential of sugar beet pulp as a platform to produce specialty and bulky chemicals as a promising pathway for sustainable biochemicals – mind the pulp. This study proposes a biorefinery concept to produce food additives (pectin-derived oligosaccharides) and bulky chemicals (terephthalic acid). Since the biorefinery has a low technology readiness level (TRL = 1), it is relevant to evaluate the feasibility of this biorefinery concept to provide guidance (at an early stage) on the environmental and economic advantages and limitations. For this purpose, the life cycle assessment and techno-economic assessment frameworks are used to assess the environmental impact and economic performance of the biobased terephthalic acid, respectively. Moreover, environmental impacts are accounted for in economic terms using different monetary valuation methods (environmental prices, Ecovalue12, and Ecotax). The environmental impact of biobased terephthalic acid was higher in most impact categories than the fossil counterpart, depending on the selected allocation approach (mass vs economic). The economic feasibility of the proposed biorefinery is highly dependent on the pectin-derived oligosaccharides market price and the valorization of byproducts (humins and levulinic acid). The selection of the monetary valuation method is critical for monetizing environmental impacts when comparing biobased against fossil-based alternatives.

Deep anthropogenic impacts on benthic marine diversity of the Humboldt Current Marine Ecosystem: Insights from a Quaternary fossil baseline

The Humboldt Current Marine Ecosystem (HCE) is one of the most productive areas in the global ocean, but current anthropogenic stressors, particularly overfishing, pose a significant threat to marine biodiversity. Moreover, the limited time scale of modern assessments may underestimate the magnitude of human alterations to marine biodiversity. Here we use the rich Quaternary fossil record present along the HCE coast, encompassing the last ca. 500 kyr, to build a baseline to evaluate the impact of human activities on the diversity of mollusk assemblages. We compiled an extensive database of &amp;gt;13,000 occurrences and ca. 370,000 individuals of 164 species of gastropods and bivalves from modern and fossiliferous outcrops from southern Peru to northern Chile (15-30°S). We tested for changes in coverage-based species richness, species dominance, species composition (Chao dissimilarity, unweighted and weighted by abundance), and the relative abundance (i.e., the proportion of individuals) of species exploited by the artisanal fisheries. Comparisons between fossil and modern assemblages were carried out at different scales of spatial aggregation to buffer against inherent differences in spatial and temporal averaging. Species composition shows remarkable stability in fossil assemblages, from Middle Pleistocene to Holocene, at most scales of spatial aggregation. Modern assemblages showed drastic alterations compared to fossil counterparts when analyses considered spatial aggregation scales, i.e., significant changes in species composition, and a 3 to 6-fold reduction in the relative abundance of exploited species, but not changes in species richness and dominance. Results suggest that contemporaneous anthropogenic activities disrupted a long-term stability in the species composition. The diversity of modern mollusk assemblages is unseen in the past 500 kyr and seems deeply perturbated by overfishing. Our synthesis sets the foundations for a conservation paleobiology approach to robustly understand the impacts of anthropogenic stressors at the HCE.

Brachiopod Fauna from the Deep Mediterranean Sea: Distribution Patterns and Ecological Preferences

Compared to their fossil counterparts, living brachiopods are investigated far less often, due to their occurrence in remote environments such as dark caves or deep environments. Due to the scarcity of studies targeting in situ brachiopods’ populations, large-scale information on their distribution and ecological preferences is still lacking, especially on hardgrounds. The extensive employment of remotely operated vehicles (ROVs), however, has opened up the chance to better explore this taxon’s diversity and ecology in the mesophotic and bathyal zones. The analysis of over 600 h of video footage collected from 624 sites, from 40 m to 1825 m, located along the Ligurian and Tyrrhenian coasts of Italy and the Sicily Channel, allowed for a large-scale investigation. The four identified species, Novocrania anomala, Gryphus vitreus, Megerlia truncata and Terebratulina retusa, emerged as common macrofaunal components of the explored habitats, especially between 150 m and 250 m, with high occurrences in the northern areas, especially on offshore seamounts. All species can form dense aggregations of individuals, with M. truncata showing the densest populations on steep rocky terraces (up to 773 individuals m−2). Except for G. vitreus, the only species also recorded on soft bottoms, the others were found exclusively on hardgrounds, with N. anomala showing a peculiar ability to exploit anthropogenic substrates such as terracotta amphorae. No stable species-specific associations were noted, even if numerous species were frequently observed together. Although brachiopods do not show the conspicuous tridimensionality of large filter-feeders, their substrate occupancy and their role in pelagic–benthic processes support their importance in deep-sea Mediterranean ecosystems.

Economic and Environmental Barriers of CO2-Based Fischer-Tropsch Electro-Diesel.

Electro-fuels are seen as a promising alternative to curb carbon emissions in the transport sector due to their appealing properties, similar to those of their fossil counterparts, allowing them to use current infrastructure and state-of-the-art automotive technologies. However, their broad implications beyond climate change remain unclear as previous studies mainly focused on analyzing their carbon footprint. To fill this gap, here, we evaluated the environmental and economic impact of Fischer–Tropsch electro-diesel (FT e-diesel) synthesized from electrolytic H2 and captured CO2. We consider various power (wind, solar, nuclear, or the current mix) and carbon sources (capture from the air (DAC) or a coal power plant) while covering a range of impacts on human health, ecosystems, and resources. Applying process simulation and life cycle assessment (LCA), we found that producing e-diesel from wind and nuclear H2 combined with DAC CO2 could reduce the carbon footprint relative to fossil diesel, leading to burden-shifting in human health and ecosystems. Also, it would incur prohibitive costs, even when considering externalities (i.e., indirect costs of environmental impacts). Overall, this work highlights the need to embrace environmental impacts beyond climate change in the analysis of alternative fuels and raises concerns about the environmental appeal of electro-fuels.

The impact of paleoclimatic changes on body size evolution in marine fishes

Body size is an important species trait, correlating with life span, fecundity, and other ecological factors. Over Earth's geological history, climate shifts have occurred, potentially shaping body size evolution in many clades. General rules attempting to summarize body size evolution include Bergmann's rule, which states that species reach larger sizes in cooler environments and smaller sizes in warmer environments, and Cope's rule, which poses that lineages tend to increase in size over evolutionary time. Tetraodontiform fishes (including pufferfishes, boxfishes, and ocean sunfishes) provide an extraordinary clade to test these rules in ectotherms owing to their exemplary fossil record and the great disparity in body size observed among extant and fossil species. We examined Bergmann's and Cope's rules in this group by combining phylogenomic data (1,103 exon loci from 185 extant species) with 210 anatomical characters coded from both fossil and extant species. We aggregated data layers on paleoclimate and body size from the species examined, and inferred a set of time-calibrated phylogenies using tip-dating approaches for downstream comparative analyses of body size evolution by implementing models that incorporate paleoclimatic information. We found strong support for a temperature-driven model in which increasing body size over time is correlated with decreasing oceanic temperatures. On average, extant tetraodontiforms are two to three times larger than their fossil counterparts, which otherwise evolved during periods of warmer ocean temperatures. These results provide strong support for both Bergmann's and Cope's rules, trends that are less studied in marine fishes compared to terrestrial vertebrates and marine invertebrates.