Paleo-ecological niche modeling (paleoENM) estimates the niches and distributions of extinct species using fossil paleo-coordinates and local environmental data. While general circulation models (GCMs) have been used to estimate climate conditions in deep time, primarily for terrestrial vertebrates, variations in paleo-elevation models used in GCM construction can influence paleoENM outcomes. This study (1) examines the impact of the Cretaceous–Paleogene (K-Pg) mass extinction on the niche dimensions of the marine invertebrate group Turritellinae (Cerithoidea: Turritellidae) and (2) compares two paleo-elevation models’ effects on GCM-based species’ distribution predictions. Fossil occurrence data from the Maastrichtian and Danian periods were collected from the Paleobiology Database (PBDB), museum collections, and published literature. Environmental data were extracted from HadCM3L GCM simulations using Scotese- and Getech-based paleogeographic and pCO2 boundary conditions. We estimated the niche dimensions of turritellines using maximum entropy (MaxEnt) and performed ordination analysis using kernel density estimation. MaxEnt model metrics showed that the Getech-based GCM outperformed the Scotese-based GCM. Geographic projections revealed minor differences in suitable habitat between the Maastrichtian and Danian in the Getech-based GCM, but overinflated predictions in the Scotese-based GCM. Niche overlap between the Maastrichtian and Danian was high, with both GCMs supporting niche similarity and equivalency. Our results suggest that differences in elevation model boundary conditions affected predicted distribution and niche patterns. This study offers a novel approach to understanding ecological persistence in invertebrates after mass extinction events, examines the robustness of GCM boundary conditions in paleoENM studies, and provides a framework for future paleoecological research on fossil invertebrates.

Species recognition is an essential part of biological and paleontological study. In gastropods, although species are genetic entities, shell morphology continues to be used as the primary source of information to recognize most species. While there are few directly tested cases, variations in conchological characters for modern species are expected to reflect underlying genetic differences that define a biological species, an assumption that is also applied to identify species in the fossil record. Additionally, how consistently shell shape differentiates gastropod species remains poorly understood. In this study, shell shape of Recent and Pliocene–Pleistocene fossil specimens of well-known intertidal gastropods (Littorinidae, periwinkles: †Littorina petricola, Littorina keenae, and the sister-species pair Littorina plena and Littorina scutulata) from the east Pacific was analyzed using landmark-based morphometrics and compared with published molecular data. For the extant species, there is a general positive relationship between shell shape and genetic differences. Discriminant function analyses indicate distantly related species can be more reliably recognized from their shells, while closely related species have a higher error. Fossils and recent specimens were classified with similar consistency. More work is needed to illuminate whether this case applies more widely.

This work describes and discusses Permian ammonoid faunas collected in two stratigraphic sections from the Las Delicias Formation of Coahuila state, northern Mexico. The taxa identified comprise 18 species, including Demarezites quirozii new species, as well as Mexicoceras smithi (Miller and Furnish, 1940), a variety of Mexicoceras guadalupense (Girty, 1908) here upgraded to specific status. The systematic analysis of the species found allowed us to recognize two middle Permian faunal zones, represented in ascending order by the Waagenoceras dieneri-Adrianites elegans Biozone from the Wordian and the Timorites schucherti-Cibolites uddeni Biozone from the Capitanian. Thus, the relative age of the Las Difuntas-18 section is established as Wordian (middle Guadalupian), whereas the Las Manuelas I section is Wordian–Capitanian (middle–upper Guadalupian). Both ammonoid zones are correlated with those recorded in Guadalupian outcrops from the southern USA, northeastern Japan, and southern China. This faunal resemblance between Mexican ammonoids and those taxa reported in these regions (USA, Japan, and China) supports the proposal that during the middle Guadalupian there was a marine corridor through the Panthalassa Ocean, which could have connected the Paleotethys and North American regions. It should be noted that ammonoids of both studied sections from the Las Delicias Formation were correlated better with West Texas (USA) and British Columbia (Canada) faunas, which are included in the North American Realm.

UUID: https://zoobank.org/60c6c43c-6536-4fbf-a372-c610bec86626

San Sebastián Bay, in southern South America, is an emblematic area because it represents a conflict of interest between the conservation of migratory birds and marine species and the exploitation of hydrocarbons. Given the little information available about the intertidal benthic communities in this bay, this study aims to analyse shell assemblages recovered from the beach, examining drilling and crushing predation on mollusc shells. Two bivalves, Darina solenoides and Mactra fuegiensis, are being preyed upon by three potential drilling predators: the naticid Falsilunatia limbata and the muricids Xymenopsis muriciformis and Trophon geversianus. The intensity of drilling predation was high in both bivalve prey, being higher in M. fuegiensis (27.4%) than in D. solenoides (18.8%). Additionally, there was no preference observed for a particular prey size and there was also no significant correlation between the size of the prey and the predator. However, site selectivity indicated that the predator showed a preference for the central sector in D. solenoides and the umbonal sector in M. fuegiensis, that could be explained by the life modes of both prey and how they are manipulated by their predators. Finally, regarding crushing predation, the shell condition of a significant number of muricids indicates damage most probably caused by decapod crabs. This work provides valuable insights into the biotic interactions within the intertidal communities of San Sebastián Bay, located in the cold-temperate Magellanic Region. It highlights the necessity for continued research and monitoring, particularly in an already conflictive context aggravated by climate change.

We developed a cloud microphysics parameterization for the icosahedral nonhydrostatic modeling framework (ICON) model based on physics-informed machine learning (ML). By training our ML model on high-resolution simulation data, we enhance the representation of cloud microphysics in Earth system models (ESMs) compared to traditional parameterization schemes, in particular by considering the influence of high-resolution dynamics that are not resolved in coarse ESMs. We run a global, kilometer-scale ICON simulation with a one-moment cloud microphysics scheme, the complex graupel scheme, to generate 12 days of training data. Our ML approach combines a microphysics trigger classifier and a regression model. The microphysics trigger classifier identifies the grid cells where changes due to the cloud microphysical parameterization are expected. In those, the workflow continues by calling the regression model and additionally includes physical constraints for mass positivity and water mass conservation to ensure physical consistency. The microphysics trigger classifier achieves an F1 score of 0.93 on classifying unseen grid cells. The regression model reaches an $ {R}^2 $ score of 0.72 averaged over all seven microphysical tendencies on simulated days used for validation only. This results in a combined offline performance of 0.78. Using explainability techniques, we explored the correlations between input and output features, finding a strong alignment with the graupel scheme and, hence, physical understanding of cloud microphysical processes. This parameterization provides the foundation to advance the representation of cloud microphysical processes in climate models with ML, leading to more accurate climate projections and improved comprehension of the Earth’s climate system.

Although the limits of life under individual extremes have been extensively studied, systematic experiments to quantify how combined extremes set the limits to life are lacking. We investigated the combined effects of extremes in temperature, salinity (NaCl) and pH on the growth limits of the marine bacterium Halomonas hydrothermalis, to test the hypothesis that limits to growth under combinations of the extremes establish a more restricted niche than the individual extremes. We show that the combination of supra-optimal temperature, pH and NaCl act synergistically in defining the limits of growth under multiple extremes. Although at optimal growth temperatures (30°C) maximum growth was achieved at pH 7, the maximum temperature limit of 43°C was achieved at pH 8. Under these conditions, the maximum NaCl concentration limit was 6.58% (wt/vol). Decreasing the temperature to 42 and 41/40°C increased the salinity limit to 7.01 % and 8.24 %, respectively. These data show that multiple extremes restrict the limits to growth of this organism to a greater extent than individual extremes and show how natural environments with extremes of temperature, pH and salinity could have restricted microbial diversity, or be uninhabitable, even when each individual extreme lies within the bounds of known microbial growth. These data imply that ‘maps’ of the limits to the biosphere based on laboratory-derived individual extremes may over-exaggerate growth limits in natural environments, which are rarely subject to single extremes, highlighting the need for multi-parameter analyses.

Recent ice cores from the Allan Hills, a blue ice area in Antarctica, are nearly 3 million years old. These cores extend ice core chronologies, enabling new insight into key climate periods such as the Mid-Pleistocene Transition. The interpretation of these climate records is complex because of the disturbed stratigraphy in this ice. Here, we present a new three-dimensional multitrack electrical conductivity measurement method (3D ECM) to resolve layer structure. We demonstrate this technique on a cumulative 60 m of two large-diameter (241 mm) ice cores, ALHIC2201 and ALHIC2302. Measurements were taken on the upper section of both cores due to better ice core quality in this shallow ice. We find well-defined and dipping layering in both cores, averaging 29° in ALHIC2201 and 69° in ALHIC2302 from horizontal. We observe a slight decrease in dip with depth in both cores, although it only achieves statistical significance in ALHIC2302. We discuss how this new method can be applied to enable accurate, high-resolution multi-proxy record development even in ice cores with steeply dipping layers. 3D ECM improves interpretation of blue ice area cores by providing accurate, non-destructive constraints on stratigraphy.

This study investigates the accumulation of glycogen, amino acids, and fatty acids in male Mytilus coruscus during different stages of gonadal development and explores their relationships with reproductive processes. Glycogen levels were highest during the resting phase, decreasing progressively during the proliferation and maturation phases. A positive correlation was observed between glycogen and carbon content, indicating a close association between energy storage and metabolic processes. Amino acid content, particularly essential amino acids (EAAs), increased during gonadal development, reflecting the higher demand for protein synthesis and cellular metabolism. Branched-chain amino acids (BCAAs) such as isoleucine, leucine, and lysine were key in activating protein synthesis and supporting gametogenesis. Non-essential amino acids like aspartic acid, glutamic acid, and glycine also accumulate, supporting cellular function and reproductive regulation. Fatty acids, especially unsaturated fatty acids (UFAs) and polyunsaturated fatty acids (PUFAs), progressively accumulated in the testes, highlighting their role in energy supply and membrane integrity during gametogenesis. Phosphorus (P) accumulated in parallel with fatty acids, supporting DNA and RNA synthesis, energy metabolism, and cell membrane function. This study emphasizes the crucial role of these biochemical components in supporting gonadal development in male M. coruscus, providing insights into the metabolic pathways involved in marine bivalve reproduction.

The crystal structure of jungite from the Hagendorf Süd pegmatite, Bavaria, has been determined using synchrotron diffraction data collected at the Australian Synchrotron microfocus beamline MX2.

The mineral has orthorhombic symmetry, space group Aba2, with cell parameters a = 11.995(2), b = 24.692(5) and c = 9.920(2) Å. The structure was refined to wRobs = 0.063 for 3558 reflections with I > 3σ(I). It is built from double heteropolyhedral layers parallel to (010) with [Ca(H2O)6]2+ hydrated cations and H-bonded H2O in the interlayer region. The heteropolyhedral layers comprise seven-member rings of corner-connected ZnO4 and PO4 tetrahedra and Fe3+2O10 dimers of edge-shared octahedra. From the refined structural model the formula is established as [Ca(H2O)6]2Zn4Fe3+8(PO4)8(OH)12(H2O)4·4H2O. The jungite specimen also contains crystals that indexed with triclinic cell parameters, a ≈ 11.95, b = 10.05, c = 9.9 Å, α ≈ 86.7, β =89.9 and γ = 83.4°. They gave poor diffraction due to multiple components with different orientations, but it was possible to extract intensity data for a single component and solve the structure. The model contains identical double heteropolyhedral layers parallel to (010) as in the orthorhombic mineral, but differs in that the Ca atoms are coordinated predominantly to layer anions. The formula obtained from the structural model is [Ca2(H2O)5]Zn4Fe3+8(PO4)8(OH)12(H2O)4·2H2O, corresponding to a dehydrated form of jungite, with a contraction in the layer spacing from 12.35 to 10.0 Å.

In this work, we evaluated the biological and geological contributions to the formation and preservation of the oxidation zones in Ľubietová-Podlipa, Ľubietová-Svätodušná, Poniky-Farbište and Špania Dolina-Piesky. This case study highlights the importance of the biological contribution to weathering processes of ore deposits. It may be extended to other similar sites in order to assess the magnitude of biological input. Using U-Pb dating, secondary minerals from Podlipa were dated to 22 ± 6 and 19 ± 4 Ma (Lower Miocene). At this time, this region experienced deep weathering under a humid and warm climate and tectonic quiescence. The isotopic (O, H) composition of the secondary minerals shows that they formed from Lower Miocene meteoric water under surface temperatures. The δ13CPDB values in malachite (–19 to –17‰) document a biological source of C, from soil CO2. The δ18OVSMOW values of the PO4 groups in the accessory fluorapatite in the host rocks (1.8 ± 1.7‰, 1σ) and pseudomalachite in the oxidation zone (12.1 ± 2.9‰, 1σ) show substantial biological P input into the oxidation zone. A biogenic source of both C and P agrees well with the palaeoclimatic constraints based on the radiometric dating. The oxidation zones at Podlipa, Svätodušná and Farbište are contemporaneous with kaolin crusts in the same area; they were all preserved only where they were covered by young (14–12 Ma) volcanic rocks and exposed recently by erosion. The other oxidation zones in the Tatric and Veporic units, if they existed, were destroyed by the Pliocene uplift of these units. The oxidation zone at Piesky is younger, dated to 2.5 Ma (Early Pleistocene) when the global temperatures in interglacials were similar to the present, decreasing in glacials by ∼4°C. The different climate at this time is manifested by scattered δ13C values, reflecting surface temperature and vegetation fluctuations at this time.