Smithsonian Institution

Mesopelagic ecosystems are vital to the ocean’s health yet face unprecedented threats due to accelerating climate change. Lanternfish (family Myctophidae) are key sentinels of midwater ecosystem health because they dominate mesopelagic fish biomass and mediate energy, nutrient, and carbon transfer across ocean layers. Despite their ecological importance, very little is known about their potential response to climate change stressors due to logistical challenges when studying mesopelagic ecosystems. We use thousands of fossil fish otoliths (calcium carbonate ear stones) recovered from marine surface sediments to reconstruct lanternfish growth, body size and energetic investment across contrasting oceanographic regimes. We compare assemblages from the highly productive, but oxygen-poor Tropical Eastern Pacific (TEP) and the oligotrophic, well-ventilated Caribbean, to test how oxygen availability and food supply shape mesopelagic fish energetics across the Isthmus of Panama. Otoliths from marine sediments serve as a cost-efficient, powerful archive to overcome methodological barriers and allow us to reconstruct long-term changes in lanternfish dynamics. We quantify energetic changes in lanternfish assemblages by reconstructing lanternfish body size estimates and mean per-capita biomass from otolith measurements and growth trajectories derived from increment biochronologies. Our results reveal anomalously small lanternfish in the TEP today, despite the region’s tendency to host larger fishes relative to the Caribbean, providing the first indication that mesopelagic fish size is potentially related to oxygen limitation. We then extend this approach to fossil otoliths to explore changes before the closure of the Isthmus of Panama using the Late Miocene/Pliocene as an analog system for warmer than modern conditions to test how mesopelagic ecosystems might respond to future climate change. We find that lanternfish dominated Panama’s ancient fish assemblages in the Caribbean but declined in relative abundance toward the Isthmus closure, while their mean per-capita biomass remained stable over the past 8 Ma. These results imply higher lanternfish biomass during periods of prolonged warming and lower biomass under less productive, better-oxygenated Caribbean conditions created by the Isthmus uplift. Yet in contrast to Panama’s geological past, our results suggest that oxygen availability exerts a dominant control on lanternfish energetics and production in the modern TEP. By integrating otolith archives from deep time to the recent past, we mapped shifts in lanternfish energetics in response to major environmental changes, revealing their sensitivity to oxygen availability and indicating that projected ocean deoxygenation might constrain the energetic capacity of the mesopelagic zone in a future ocean.

Interactions between magmas and organic matter from host sedimentary rocks may lead to ore mineralization [1], hydrocarbon cracking [2] and thermogenic gas emissions [3], potentially disrupting the global carbon cycle. We reconstructed magma–hydrocarbon interaction processes by studying basaltic melts intruding bitumen- and oil-bearing sandstones in a continental rift setting, combining detailed field observations with geochemical analyses, melt and fluid inclusions study [4]. Our case study is Bile Island in the Oslo Fjord (Norway), where Upper Silurian sandstones are crosscut by a pyrobitumen-bearing sill and several dykes, which date back to the Oslo Rift activity, the northernmost branch of the 300 Myr-old Skagerrak Large Igneous Province [5]. These intrusions represent the magma plumbing system of an adjacent basaltic volcano from the earliest phase of the Oslo Rift, and the sedimentary succession in this area contains oil and bitumen mainly sourced from Cambrian–Ordovician organic-rich shales. Our multi-technique approach characterized the transformation of bitumen and oil into pyrobitumen along with abundant methane (CH4) and ethane (C2H6) emissions. Our geochemical dataset described element exchange and mass transfer between melts, fluids and host rocks, from magmatic to hydrothermal stages, depicting a scenario with magmatic intrusions of a large mafic complex intersecting a pre-existing petroleum system. Bile Island yields an extraordinary record, where magmatic and sedimentary carbon is synchronously released via the same volcanic vent(s), providing a viable explanation for methane emissions in volcanic areas and offering a new paradigm for degassing in the context of Large Igneous Provinces. [1] Hoggard et al. (2020), Nat. Geosci. 13, 504–510.[2] Senger et al. (2017), First Break 35, 47–56.[3] Svensen et al. (2004), Nature 429, 542–545.[4] Capriolo et al. (2026), J. Geol. Soc. https://doi.org/10.1144/jgs2025-094.[5] Torsvik et al. (2008), Earth Planet. Sci. Lett. 267, 444–452.

Adolescent girls and young women (AGYW) often seek emergency contraceptive pills (ECP) within 72 hr of condomless sex, a critical period for HIV exposure prevention through testing and postexposure prophylaxis (PEP). Pharmacies, where most AGYW obtain ECP, provide an ideal setting for timely HIV prevention services. From May to October 2023, a longitudinal study was conducted among AGYW ages 15-24 years seeking ECP in five pharmacies in Nairobi and Kisumu. Eligible participants were not on preexposure prophylaxis and provided consent. Baseline and 10-day optional follow-up phone data assessed HIV testing history, risk perception, and willingness to test or start PEP. Of 297 screened, 200 enrolled (mean age = 22 years). Nearly all (97.5%) had previously tested for HIV; 79% were interested in pharmacy-based testing and 73% in PEP. By follow-up, 50.7% tested for HIV, and 10.5% initiated PEP. These findings suggest that pharmacies offer a promising avenue to link ECP users to timely HIV prevention service.

Body fluid identification at crime scenes is the first step in the forensic biology workflow, leading to the identification of the perpetrator and/or, in some cases, the victim. Current methods that are regularly used in forensic criminal evidence analysis utilize well-studied properties of each fluid as the foundation of the protocol. Among these approaches, alternative light sources, chemical reactions, lateral flow immunochromatographic tests, and microscopic detection stand out to identify the main body fluids encountered at crime scenes: blood, semen, and saliva. However, these often come with limits for specificity and sensitivity. There is also difficulty with fluid mixtures, environmental degradation, and destruction of the sample by the method used. Other fluids, like vaginal fluid and fecal matter, lack standardized protocols and require innovative ideas for accurate analysis without compromising the sample. Emerging technologies based on molecular methods have been the focus of body fluid research, with emphasis on topics such as mRNA, microRNA, epigenetics, and microbial analysis. Additional information alongside the determination of fluid origin could be an advantage from new molecular techniques, such as the identification of donors from SNP analysis, if regular STR analysis is not possible. Validation studies and the integration of such research have the potential to expand and enhance the laboratory practices of forensic science. This article will provide an overview of the current methods applied in the crime lab for body fluid identification before exploring active research in this field, pointing out the potential of these techniques for application in forensic cases to overcome present issues and expand the variety of body fluids identified.

High-frequency hearing evolved in most amniote lineages in the Permian and Triassic. However, for reptiles, the evolutionary history of hearing is more elusive. Some have suggested that tympanic hearing evolved independently in each major lineage of reptile, largely based on gross observations of the stapes and outer ear region of fossils. On that basis, it was postulated that many Permian stem reptiles could not hear high frequencies. However, this hypothesis lacks quantitative support. To our knowledge, biomechanical analyses have not previously been conducted to determine the capacity for hearing in stem reptiles. Here, we conduct functional and morphometric analyses of the reptilian stapes including fossil data. Using harmonic response analyses, we demonstrate that the stapes of the stem reptile Youngina capensis could be displaced proximodistally at values similar to tympanic squamates. Additionally, Y. capensis is predicted to possess a tympanum based on a flexible discriminant analysis, while early-diverging stem reptiles are classified as low-frequency bone conductors. We show that hearing was facilitated by the formation of the annular ligament, improving stapedial movement, in addition to the evolution of a slender stapes and tympanum. Our results suggest that relatively high-frequency hearing was present in the common ancestor of reptiles, originating by the late Permian.

The pace of change in ecological communities is central to classic and emerging problems in paleobiology and ecology. Yet measuring rates of change in community composition is problematic: traditional ecological rates (ecological distance divided by time) appear faster when measured over shorter time intervals, preventing straightforward interpretation of rates when time-scales vary. Similar problems arise when richness or sample size varies. We develop an approach that mitigates these issues using Hubbell's neutral theory, a model in which species abundances change through stochastic births and deaths in a community with a fixed number of individuals J. Change in community composition is faster for smaller J, so 1/J provides a process-based rate metric that can be estimated from empirical time-series. We derive the likelihood for changes in community composition under neutral theory. Our approach accurately estimates rates in simulated data even when time-scale, richness, and sample size vary. We use Quaternary pollen cores to demonstrate the power of this method for comparing rates between sites and across time and testing for rate shifts. Our approach can be flexibly adapted to test hypotheses on the causes of ecological change, including tests of coordinated stasis, neutral theory, and the timing of anthropogenic change.

The five species of the New World genus Amphicnephes Loew are revised, including A. floridensis, new species from USA (Florida, Georgia) and A. mexicanus, new species from Mexico (Oaxaca). Diagnoses, descriptions, and illustrations are provided for all five species, as well as an identification key. Distribution data based on examined specimens and iNaturalist observations are provided. COI barcodes were obtained for A. pullus (Wiedemann) and A. stellatus Wulp. A neotype is designated for Trypeta pulla Wiedeman, 1830 and a lectotype for Amphicnephes pertusus Loew, 1873.