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Abstract This editorial introduces the “Holocene palaeoclimate” special collection, which examines the intricate relationship between human activities and climate systems throughout the Holocene. The collection highlights the significance of palaeoclimatic reconstructions, providing insights into past climate variability and extremes. By integrating multidisciplinary research from diverse regions, including the Siberian Arctic, Singapore, the Iberian Peninsula, Bavaria, and Madagascar, the collection elucidates the global and regional climate dynamics that shaped historical and contemporary environments. These studies underscore the value of understanding past climates to better predict future climate behaviour and develop strategies to mitigate the impacts of ongoing global warming. The findings offer a long-term perspective on climate trends, contributing to more informed and resilient approaches to addressing contemporary climate challenges.

Abstract Using LIBS for the analysis of archaeological and geological marine mollusc shells is a growing research area that relies on customised instrumentation and specific workflows that can accommodate the variety and precision of the required sampling parameters. However, the increased efficiency offered by LIBS, which enables the study of a larger quantity of shell samples for temperature variation, ecological parameters, and human consumption practices, outweighs the initial efforts required to develop customised instrumentation and workflows. In this work, we present detailed specifications and parameters for the development of a LIBS system capable of generating Mg/Ca images on marine shells that directly correlate with seasonal sea temperatures. Our main objective was to develop specifications that enable easy adaptation of LIBS systems to existing laboratories for studying hard-tissue samples. These specifications were used to develop a customised micro-LIBS system and apply it to a real-world example of an archaeological study to better understand its efficiency on the marine mollusc shells and demonstrate its potential for broader applications in interdisciplinary research. In total 101 shell specimens have been analysed within a time frame of approximately 71 h of machine time, producing 234 images (100 µm resolution: 100 images, 30 µm resolution: 134 images). SEM analysis of the irradiated sections of the shell revealed a primary ablated area of 10–15 µm in diameter, while a secondary affected area of the shell’s crystal fabric extended to 30–50 µm after repeated shots. Overall, this new customised system reliably and efficiently analysed marine mollusc specimens without major destructive effects, enabling additional analyses for other proxies to be carried out. This study highlights the potential of the LIBS method for interdisciplinary research, encompassing applications in paleoclimatology, marine ecology, and archaeology.

[This corrects the article DOI: 10.1371/journal.pone.0217596.].

Annual growth patterns in marine mollusc shells are valuable indicators of the condition of marine ecology through time. In archaeological contexts, the mollusc’s time of death (i.e. the last season of growth) is an indicator of human exploitation patterns throughout the year, enabling the reconstruction of when and how often gathering occurred as well as when sites were occupied. Both pieces of information, growth rate and season of death, are vital for understanding exploitation pressure(s) in the past, and building baselines for modern environmental policies that secure sustainable marine resources. Previously, these parameters have been determined by incremental growth-line or isotopic analyses, which are time consuming and often expensive techniques, thus restricting sample size and the overall robustness of palaeoecological interpretations. Here, we apply Laser Induced Breakdown Spectroscopy (LIBS) to produce elemental maps (Mg/Ca) with the potential to trace and display growth patterns quickly, and at a reduced cost. We further compare the elemental maps with the results obtained from incremental growth-line analysis to provide a structural context for the geochemical data, and demonstrate the utility of an integrated methodological approach. Our pilot study was undertaken on 12 European oysters ('Ostrea edulis', Linnaeus, 1758) from the Late Mesolithic shell midden at Conors Island, Co. Sligo in the Republic of Ireland. Our LIBS analysis enabled us to accurately and quickly determine repeating growth patterns, which were often in agreement with the annual growth increments visible through the microscopic analysis. Based on this comparative dataset, including structural and geochemical patterns, the Late Mesolithic site of Conors Island had been occupied throughout the year. Moreover, our analyses highlight the applicability of LIBS to determine prehistoric seasonality practices as well as biological age and growth at an improved rate and reduced cost than was previously achievable.

During the past decade, over 3000 shell middens or shell matrix deposits have been discovered on the Farasan Islands in the southern Red Sea, dating to the period c. 7,360 to 4,700 years ago. Many of the sites are distributed along a palaeoshoreline which is now 2-3 m above present sea level. Others form clusters with some sites on the shoreline and others located inland over distances of c. 30 m to 1 km. We refer to these inland sites as 'post-shore' sites. Following Meehan, who observed a similar spatial separation in shell deposition in her ethnographic study of Anbarra shellgathering in the Northern Territory of Australia, we hypothesise that the shoreline sites are specialised sites for the processing or immediate consumption of shell food, and the post-shore sites are habitation sites used for a variety of activities. We test this proposition through a systematic analysis of 55 radiocarbon dates and measurement of shell quantities from the excavation of 15 shell matrix sites in a variety of locations including shoreline and post-shore sites. Our results demonstrate large differences in rates of shell accumulation between these two types of sites and selective removal of shoreline sites by changes in sea level. We also discuss the wider implications for understanding the differential preservation and visibility of shell-matrix deposits in coastal settings in other parts of the world extending back into the later Pleistocene in association with periods of lowersea level. Our results highlight the importance of taphonomic factors of post-depositional degradation and destruction, rates of shell accumulation, the influence on site location of factors other than shell food supply, and the relative distance of deposits from their nearest palaeoshorelines as key variables in the interpretation of shell quantities. Failure to take these variables into account when investigating shells and shell-matrix deposits in late Pleistocene and early Holocene contexts is likely to compromise interpretations of the role and significance of shell food in human evolutionary and socio-cultural development.

Electrochemical production of large-scale chemicals and fuels is critical to reaching carbon neutrality. However, the required anodic oxidation reactions, namely the oxygen evolution reaction (OER) or the oxidation of organics into value-added products, suffer from large overpotentials. To address this challenge, researchers have been widely investigating non-water-soluble (pre)catalysts to operate in the aqueous electrolyte. On the contrary, in this work, we approach a rapid, easy, and green carbon cloth electrode preparation using merely water-soluble nitrate precursors and ethanol as chemicals and no heating steps. The drop-coated, water-soluble transition metal salts reconstruct rapidly into the respective oxyhydroxides under OER conditions, with the oxyanion acting as a beneficial sacrificial reagent. This approach is shown herein for nickel(–iron) catalysts and their successful application for the OER (220 mV overpotential at 10 mA cm−2, long-term stability of 40 h at 100 mA cm−2) and the oxidation of 5-hydroxymethylfurfural (HMF, quantitative faradaic efficiency). We compare both reactions with both electrodes closely and find that the iron-free sample is more active for the HMF oxidation in regimes where mass transport is not the main limiting factor. We anticipate that this simple electrode preparation approach can find wide application in electrocatalysis and beyond. [ABSTRACT FROM AUTHOR]

Abstract To enable a future society based on sun and wind energy, transforming electricity into chemical energy in the form of fuels is crucial. This transformation can be achieved in an electrolyzer performing water splitting, where at the anode, water is oxidized to oxygen—oxygen evolution reaction (OER)—to produce protons and electrons that can be combined at the cathode to form hydrogen—hydrogen evolution reaction (HER). While hydrogen is a desired fuel, the obtained oxygen has no economic value. A techno‐economically more suitable alternative is hybrid water electrolysis, where value‐added oxidation reactions of abundant organic feedstocks replace the OER. However, tremendous challenges remain for the industrial‐scale application of hybrid water electrolysis. Herein, these challenges, including the higher kinetic overpotentials of organic oxidation reactions compared to the OER, the small feedstock availably and product demand of these processes compared to the HER (and carbon dioxide reduction), additional purifications costs, and electrocatalytic challenges to meet the industrially required activities, selectivities, and especially long‐term stabilities are critically discussed. It is anticipated that this perspective helps the academic research community to identify industrially relevant research questions concerning hybrid water electrolysis.

Superconductivity has not been observed in any antiperovskite oxide up to now. Here Oudahet al. report superconducting transition around 5 K in antiperovskite oxide Sr3−xSnO, making it a new class of oxide superconductors.